[v2,2/6] pci: endpoint: add support to handle features of outbound memory

From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>

rcar pcie controller has support to map multiple memory regions
for mapping the outbound memory in local system, this feature
inspires to add support for handling such features in endpoint
framework. similar features exists on other controllers where
outbound regions can be specifically used for low/high priority
transactions, and regions can be flagged and used for allocation
of large/small memory allocations.
This patch adds support to handle such features, where the
properties described for outbound regions are used whenever a
request to memory is made.

Signed-off-by: Lad, Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
 drivers/pci/controller/dwc/pcie-designware-ep.c |  30 ++--
 drivers/pci/controller/pcie-cadence-ep.c        |  11 +-
 drivers/pci/controller/pcie-rockchip-ep.c       |  13 +-
 drivers/pci/endpoint/functions/pci-epf-test.c   |  47 ++++--
 drivers/pci/endpoint/pci-epc-core.c             |   7 +-
 drivers/pci/endpoint/pci-epc-mem.c              | 216 +++++++++++++++++++-----
 include/linux/pci-epc.h                         |  72 ++++++--
 7 files changed, 307 insertions(+), 89 deletions(-)

On Fri, Dec 13, 2019 at 08:47:44AM +0000, Lad Prabhakar wrote:
> From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> rcar pcie controller has support to map multiple memory regions
> for mapping the outbound memory in local system, this feature
> inspires to add support for handling such features in endpoint
> framework. similar features exists on other controllers where
> outbound regions can be specifically used for low/high priority
> transactions, and regions can be flagged and used for allocation
> of large/small memory allocations.
> This patch adds support to handle such features, where the
> properties described for outbound regions are used whenever a
> request to memory is made.

For this and the other patches, please:

  - start sentences with a capital letter
  - leave a blank line between paragraphs
  - wrap commit log text to use the whole 80 character line (I wrap to
    75 characters to account for "git log" indenting by 4 spaces)
  - check your signed-off-by: it shows your name as "Lad, Prabhakar",
    while your email From: line shows "Lad Prabhakar".  Choose one :)

> diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
> index 2bf8bd1..4b610cd 100644
> --- a/drivers/pci/endpoint/pci-epc-mem.c
> +++ b/drivers/pci/endpoint/pci-epc-mem.c

> -int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
> -		       size_t page_size)
> +int __pci_epc_mem_init(struct pci_epc *epc, struct pci_epc_mem_window *windows,
> +		       int num_windows, size_t page_size)
>  {
> -	int ret;
> -	struct pci_epc_mem *mem;
> -	unsigned long *bitmap;
> +	struct pci_epc_mem *mem = NULL;
> +	unsigned long *bitmap = NULL;
>  	unsigned int page_shift;
> -	int pages;
>  	int bitmap_size;
> +	int pages;
> +	int ret;
> +	int i;
> +
> +	epc->mem_windows = 0;
> +
> +	if (!windows)
> +		return -EINVAL;
> +
> +	if (num_windows <= 0)
> +		return -EINVAL;

Why is num_windows signed?

>  void pci_epc_mem_exit(struct pci_epc *epc)
>  {
> -	struct pci_epc_mem *mem = epc->mem;
> +	struct pci_epc_mem *mem;
> +	int i;
> +
> +	if (!epc->mem_windows)
> +		return;

If you fix the loop below, why do you even need to test this?

> +	for (i = 0; i <= epc->mem_windows; i--) {

Huh?  "<="?  "i--"?  Surely you mean

	for (i = 0; i < epc->mem_windows; i++) {

> +		mem = epc->mem[i];
> +		kfree(mem->bitmap);
> +		kfree(epc->mem[i]);
> +	}
> +	kfree(epc->mem);
>  
>  	epc->mem = NULL;
> -	kfree(mem->bitmap);
> -	kfree(mem);
> +	epc->mem_windows = 0;
>  }
>  EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
>  
> +static int pci_epc_find_best_fit_window(struct pci_epc *epc, size_t size,
> +					u32 flags)

Can this just return a struct pci_epc_mem *, so the caller doesn't
have to lookup epc->mem[i] again?

> +{
> +	size_t window_least_size = 0;
> +	int best_fit_window = -1;
> +	struct pci_epc_mem *mem;
> +	size_t actual_size;
> +	size_t avail_size;
> +	u32 win_flags;
> +	int i;
> +
> +	for (i = 0; i < epc->mem_windows; i++) {
> +		mem = epc->mem[i];
> +		win_flags = mem->window.flags;
> +
> +		actual_size = ALIGN(size, mem->page_size);
> +		avail_size = mem->window.size - mem->window.map_size;
> +
> +		if (win_flags == 0x0) {
> +			if (best_fit_window == -1) {
> +				if (actual_size <= avail_size) {
> +					best_fit_window = i;
> +					window_least_size = mem->window.size;
> +				}
> +			} else {
> +				if (actual_size <= avail_size &&
> +				    mem->window.size < window_least_size) {
> +					best_fit_window = i;
> +					window_least_size = mem->window.size;
> +				}
> +			}
> +		} else {
> +			if (mem->window.map_size &&
> +			    (win_flags | PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC))
> +				continue;
> +
> +			if (!(win_flags | flags))
> +				continue;
> +
> +			if (best_fit_window == -1) {
> +				if (actual_size <= avail_size) {
> +					best_fit_window = i;
> +					window_least_size = mem->window.size;
> +				}
> +			} else {
> +				if (actual_size <= avail_size &&
> +				    mem->window.size < window_least_size) {
> +					best_fit_window = i;
> +					window_least_size = mem->window.size;
> +				}
> +			}
> +		}
> +	}
> +
> +	return best_fit_window;
> +}
> +
>  /**
>   * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
>   * @epc: the EPC device on which memory has to be allocated
>   * @phys_addr: populate the allocated physical address here
> + * @window: populate the window here which will be used to map PCI address
>   * @size: the size of the address space that has to be allocated
> + * @flags: look for window as requested in flags
>   *
>   * Invoke to allocate memory address from the EPC address space. This
>   * is usually done to map the remote RC address into the local system.
>   */
>  void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> -				     phys_addr_t *phys_addr, size_t size)
> +				     phys_addr_t *phys_addr,
> +				     int *window, size_t size, uint32_t flags)
>  {
> +	int best_fit = PCI_EPC_DEFAULT_WINDOW;
> +	void __iomem *virt_addr = NULL;
> +	struct pci_epc_mem *mem;
> +	unsigned int page_shift;
>  	int pageno;
> -	void __iomem *virt_addr;
> -	struct pci_epc_mem *mem = epc->mem;
> -	unsigned int page_shift = ilog2(mem->page_size);
>  	int order;
>  
> +	if (epc->mem_windows <= 0)
> +		return NULL;
> +
> +	if (epc->mem_windows > 1) {

Why bother testing epc->mem_windows here?  Just make sure
pci_epc_find_best_fit_window() returns the correct thing for
"mem_windows == 0" and "mem_windows == 1", and remove both the tests
above.

> +		best_fit = pci_epc_find_best_fit_window(epc, size, flags);
> +		if (best_fit < 0)
> +			return NULL;
> +	}
> +
> +	mem = epc->mem[best_fit];
>  	size = ALIGN(size, mem->page_size);
> +	if (size > (mem->window.size - mem->window.map_size))
> +		return NULL;
> +	page_shift = ilog2(mem->page_size);
>  	order = pci_epc_mem_get_order(mem, size);
>  
>  	pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
>  	if (pageno < 0)
>  		return NULL;
>  
> -	*phys_addr = mem->phys_base + (pageno << page_shift);
> +	*phys_addr = mem->window.phys_base + (pageno << page_shift);
>  	virt_addr = ioremap(*phys_addr, size);
> -	if (!virt_addr)
> +	if (!virt_addr) {
>  		bitmap_release_region(mem->bitmap, pageno, order);
> +	} else {
> +		mem->window.map_size += size;
> +		*window = best_fit;
> +	}
>  
>  	return virt_addr;
>  }
>  EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
>  
> +static int pci_epc_get_matching_window(struct pci_epc *epc,
> +				       phys_addr_t phys_addr)

Return struct pci_epc_mem * again?

> +{
> +	struct pci_epc_mem *mem;
> +	int i;
> +
> +	for (i = 0; i < epc->mem_windows; i++) {
> +		mem = epc->mem[i];
> +
> +		if (mem->window.phys_base == phys_addr)
> +			return i;
> +	}
> +
> +	return -EINVAL;
> +}
> +
>  /**
>   * pci_epc_mem_free_addr() - free the allocated memory address
>   * @epc: the EPC device on which memory was allocated
> @@ -155,16 +281,26 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
>  void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
>  			   void __iomem *virt_addr, size_t size)
>  {
> +	struct pci_epc_mem *mem;
> +	unsigned int page_shift;
> +	int window = 0;
>  	int pageno;
> -	struct pci_epc_mem *mem = epc->mem;
> -	unsigned int page_shift = ilog2(mem->page_size);
>  	int order;
>  
> +	if (epc->mem_windows > 1) {

Same here (unnecessary test).

> +		window = pci_epc_get_matching_window(epc, phys_addr);
> +		if (window < 0)
> +			return;
> +	}
> +
> +	mem = epc->mem[window];
> +	page_shift = ilog2(mem->page_size);
>  	iounmap(virt_addr);
> -	pageno = (phys_addr - mem->phys_base) >> page_shift;
> +	pageno = (phys_addr - mem->window.phys_base) >> page_shift;
>  	size = ALIGN(size, mem->page_size);
>  	order = pci_epc_mem_get_order(mem, size);
>  	bitmap_release_region(mem->bitmap, pageno, order);
> +	mem->window.map_size -= size;
>  }
>  EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);

> @@ -85,7 +126,8 @@ struct pci_epc_mem {
>   * @dev: PCI EPC device
>   * @pci_epf: list of endpoint functions present in this EPC device
>   * @ops: function pointers for performing endpoint operations
> - * @mem: address space of the endpoint controller
> + * @mem: array of address space of the endpoint controller
> + * @mem_windows: number of windows supported by device
>   * @max_functions: max number of functions that can be configured in this EPC
>   * @group: configfs group representing the PCI EPC device
>   * @lock: spinlock to protect pci_epc ops
> @@ -94,7 +136,8 @@ struct pci_epc {
>  	struct device			dev;
>  	struct list_head		pci_epf;
>  	const struct pci_epc_ops	*ops;
> -	struct pci_epc_mem		*mem;
> +	struct pci_epc_mem		**mem;
> +	int				mem_windows;

Can't this be unsigned int and then there's no need to check
"mem_windows < 0"?

>  	u8				max_functions;
>  	struct config_group		*group;
>  	/* spinlock to protect against concurrent access of EP controller */

Hi Bjorn,

thank you for the review.

On Fri, Dec 13, 2019 at 9:06 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Fri, Dec 13, 2019 at 08:47:44AM +0000, Lad Prabhakar wrote:
> > From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > rcar pcie controller has support to map multiple memory regions
> > for mapping the outbound memory in local system, this feature
> > inspires to add support for handling such features in endpoint
> > framework. similar features exists on other controllers where
> > outbound regions can be specifically used for low/high priority
> > transactions, and regions can be flagged and used for allocation
> > of large/small memory allocations.
> > This patch adds support to handle such features, where the
> > properties described for outbound regions are used whenever a
> > request to memory is made.
>
> For this and the other patches, please:
>
>   - start sentences with a capital letter
>   - leave a blank line between paragraphs
>   - wrap commit log text to use the whole 80 character line (I wrap to
>     75 characters to account for "git log" indenting by 4 spaces)
>   - check your signed-off-by: it shows your name as "Lad, Prabhakar",
>     while your email From: line shows "Lad Prabhakar".  Choose one :)
>
sure will fix it next version.

> > diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
> > index 2bf8bd1..4b610cd 100644
> > --- a/drivers/pci/endpoint/pci-epc-mem.c
> > +++ b/drivers/pci/endpoint/pci-epc-mem.c
>
> > -int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
> > -                    size_t page_size)
> > +int __pci_epc_mem_init(struct pci_epc *epc, struct pci_epc_mem_window *windows,
> > +                    int num_windows, size_t page_size)
> >  {
> > -     int ret;
> > -     struct pci_epc_mem *mem;
> > -     unsigned long *bitmap;
> > +     struct pci_epc_mem *mem = NULL;
> > +     unsigned long *bitmap = NULL;
> >       unsigned int page_shift;
> > -     int pages;
> >       int bitmap_size;
> > +     int pages;
> > +     int ret;
> > +     int i;
> > +
> > +     epc->mem_windows = 0;
> > +
> > +     if (!windows)
> > +             return -EINVAL;
> > +
> > +     if (num_windows <= 0)
> > +             return -EINVAL;
>
> Why is num_windows signed?
>
> >  void pci_epc_mem_exit(struct pci_epc *epc)
> >  {
> > -     struct pci_epc_mem *mem = epc->mem;
> > +     struct pci_epc_mem *mem;
> > +     int i;
> > +
> > +     if (!epc->mem_windows)
> > +             return;
>
> If you fix the loop below, why do you even need to test this?
>
yes makes sense will drop this check.

> > +     for (i = 0; i <= epc->mem_windows; i--) {
>
> Huh?  "<="?  "i--"?  Surely you mean
>
>         for (i = 0; i < epc->mem_windows; i++) {
>
oops my bad, will fix it.

> > +             mem = epc->mem[i];
> > +             kfree(mem->bitmap);
> > +             kfree(epc->mem[i]);
> > +     }
> > +     kfree(epc->mem);
> >
> >       epc->mem = NULL;
> > -     kfree(mem->bitmap);
> > -     kfree(mem);
> > +     epc->mem_windows = 0;
> >  }
> >  EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
> >
> > +static int pci_epc_find_best_fit_window(struct pci_epc *epc, size_t size,
> > +                                     u32 flags)
>
> Can this just return a struct pci_epc_mem *, so the caller doesn't
> have to lookup epc->mem[i] again?
>
yes makes sense will change it to return struct pci_epc_mem *

> > +{
> > +     size_t window_least_size = 0;
> > +     int best_fit_window = -1;
> > +     struct pci_epc_mem *mem;
> > +     size_t actual_size;
> > +     size_t avail_size;
> > +     u32 win_flags;
> > +     int i;
> > +
> > +     for (i = 0; i < epc->mem_windows; i++) {
> > +             mem = epc->mem[i];
> > +             win_flags = mem->window.flags;
> > +
> > +             actual_size = ALIGN(size, mem->page_size);
> > +             avail_size = mem->window.size - mem->window.map_size;
> > +
> > +             if (win_flags == 0x0) {
> > +                     if (best_fit_window == -1) {
> > +                             if (actual_size <= avail_size) {
> > +                                     best_fit_window = i;
> > +                                     window_least_size = mem->window.size;
> > +                             }
> > +                     } else {
> > +                             if (actual_size <= avail_size &&
> > +                                 mem->window.size < window_least_size) {
> > +                                     best_fit_window = i;
> > +                                     window_least_size = mem->window.size;
> > +                             }
> > +                     }
> > +             } else {
> > +                     if (mem->window.map_size &&
> > +                         (win_flags | PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC))
> > +                             continue;
> > +
> > +                     if (!(win_flags | flags))
> > +                             continue;
> > +
> > +                     if (best_fit_window == -1) {
> > +                             if (actual_size <= avail_size) {
> > +                                     best_fit_window = i;
> > +                                     window_least_size = mem->window.size;
> > +                             }
> > +                     } else {
> > +                             if (actual_size <= avail_size &&
> > +                                 mem->window.size < window_least_size) {
> > +                                     best_fit_window = i;
> > +                                     window_least_size = mem->window.size;
> > +                             }
> > +                     }
> > +             }
> > +     }
> > +
> > +     return best_fit_window;
> > +}
> > +
> >  /**
> >   * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
> >   * @epc: the EPC device on which memory has to be allocated
> >   * @phys_addr: populate the allocated physical address here
> > + * @window: populate the window here which will be used to map PCI address
> >   * @size: the size of the address space that has to be allocated
> > + * @flags: look for window as requested in flags
> >   *
> >   * Invoke to allocate memory address from the EPC address space. This
> >   * is usually done to map the remote RC address into the local system.
> >   */
> >  void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> > -                                  phys_addr_t *phys_addr, size_t size)
> > +                                  phys_addr_t *phys_addr,
> > +                                  int *window, size_t size, uint32_t flags)
> >  {
> > +     int best_fit = PCI_EPC_DEFAULT_WINDOW;
> > +     void __iomem *virt_addr = NULL;
> > +     struct pci_epc_mem *mem;
> > +     unsigned int page_shift;
> >       int pageno;
> > -     void __iomem *virt_addr;
> > -     struct pci_epc_mem *mem = epc->mem;
> > -     unsigned int page_shift = ilog2(mem->page_size);
> >       int order;
> >
> > +     if (epc->mem_windows <= 0)
> > +             return NULL;
> > +
> > +     if (epc->mem_windows > 1) {
>
> Why bother testing epc->mem_windows here?  Just make sure
> pci_epc_find_best_fit_window() returns the correct thing for
> "mem_windows == 0" and "mem_windows == 1", and remove both the tests
> above.
>
will fix that.

> > +             best_fit = pci_epc_find_best_fit_window(epc, size, flags);
> > +             if (best_fit < 0)
> > +                     return NULL;
> > +     }
> > +
> > +     mem = epc->mem[best_fit];
> >       size = ALIGN(size, mem->page_size);
> > +     if (size > (mem->window.size - mem->window.map_size))
> > +             return NULL;
> > +     page_shift = ilog2(mem->page_size);
> >       order = pci_epc_mem_get_order(mem, size);
> >
> >       pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
> >       if (pageno < 0)
> >               return NULL;
> >
> > -     *phys_addr = mem->phys_base + (pageno << page_shift);
> > +     *phys_addr = mem->window.phys_base + (pageno << page_shift);
> >       virt_addr = ioremap(*phys_addr, size);
> > -     if (!virt_addr)
> > +     if (!virt_addr) {
> >               bitmap_release_region(mem->bitmap, pageno, order);
> > +     } else {
> > +             mem->window.map_size += size;
> > +             *window = best_fit;
> > +     }
> >
> >       return virt_addr;
> >  }
> >  EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
> >
> > +static int pci_epc_get_matching_window(struct pci_epc *epc,
> > +                                    phys_addr_t phys_addr)
>
> Return struct pci_epc_mem * again?
>
yes makes sense.

> > +{
> > +     struct pci_epc_mem *mem;
> > +     int i;
> > +
> > +     for (i = 0; i < epc->mem_windows; i++) {
> > +             mem = epc->mem[i];
> > +
> > +             if (mem->window.phys_base == phys_addr)
> > +                     return i;
> > +     }
> > +
> > +     return -EINVAL;
> > +}
> > +
> >  /**
> >   * pci_epc_mem_free_addr() - free the allocated memory address
> >   * @epc: the EPC device on which memory was allocated
> > @@ -155,16 +281,26 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
> >  void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
> >                          void __iomem *virt_addr, size_t size)
> >  {
> > +     struct pci_epc_mem *mem;
> > +     unsigned int page_shift;
> > +     int window = 0;
> >       int pageno;
> > -     struct pci_epc_mem *mem = epc->mem;
> > -     unsigned int page_shift = ilog2(mem->page_size);
> >       int order;
> >
> > +     if (epc->mem_windows > 1) {
>
> Same here (unnecessary test).
>
will drop it.

> > +             window = pci_epc_get_matching_window(epc, phys_addr);
> > +             if (window < 0)
> > +                     return;
> > +     }
> > +
> > +     mem = epc->mem[window];
> > +     page_shift = ilog2(mem->page_size);
> >       iounmap(virt_addr);
> > -     pageno = (phys_addr - mem->phys_base) >> page_shift;
> > +     pageno = (phys_addr - mem->window.phys_base) >> page_shift;
> >       size = ALIGN(size, mem->page_size);
> >       order = pci_epc_mem_get_order(mem, size);
> >       bitmap_release_region(mem->bitmap, pageno, order);
> > +     mem->window.map_size -= size;
> >  }
> >  EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
>
> > @@ -85,7 +126,8 @@ struct pci_epc_mem {
> >   * @dev: PCI EPC device
> >   * @pci_epf: list of endpoint functions present in this EPC device
> >   * @ops: function pointers for performing endpoint operations
> > - * @mem: address space of the endpoint controller
> > + * @mem: array of address space of the endpoint controller
> > + * @mem_windows: number of windows supported by device
> >   * @max_functions: max number of functions that can be configured in this EPC
> >   * @group: configfs group representing the PCI EPC device
> >   * @lock: spinlock to protect pci_epc ops
> > @@ -94,7 +136,8 @@ struct pci_epc {
> >       struct device                   dev;
> >       struct list_head                pci_epf;
> >       const struct pci_epc_ops        *ops;
> > -     struct pci_epc_mem              *mem;
> > +     struct pci_epc_mem              **mem;
> > +     int                             mem_windows;
>
> Can't this be unsigned int and then there's no need to check
> "mem_windows < 0"?
>
yes will change it unsigned int.

Cheers,
--Prabhakar

> >       u8                              max_functions;
> >       struct config_group             *group;
> >       /* spinlock to protect against concurrent access of EP controller */

Hi Prabhakar,

On 13/12/19 2:17 pm,  wrote:
> From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>
> 
> rcar pcie controller has support to map multiple memory regions
> for mapping the outbound memory in local system, this feature
> inspires to add support for handling such features in endpoint
> framework. similar features exists on other controllers where
> outbound regions can be specifically used for low/high priority
> transactions, and regions can be flagged and used for allocation
> of large/small memory allocations.
> This patch adds support to handle such features, where the
> properties described for outbound regions are used whenever a
> request to memory is made.
> 
> Signed-off-by: Lad, Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
>   drivers/pci/controller/dwc/pcie-designware-ep.c |  30 ++--
>   drivers/pci/controller/pcie-cadence-ep.c        |  11 +-
>   drivers/pci/controller/pcie-rockchip-ep.c       |  13 +-
>   drivers/pci/endpoint/functions/pci-epf-test.c   |  47 ++++--
>   drivers/pci/endpoint/pci-epc-core.c             |   7 +-
>   drivers/pci/endpoint/pci-epc-mem.c              | 216 +++++++++++++++++++-----
>   include/linux/pci-epc.h                         |  72 ++++++--
>   7 files changed, 307 insertions(+), 89 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 3dd2e26..be6aa94 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -195,7 +195,7 @@ static void dw_pcie_ep_unmap_addr(struct pci_epc *epc, u8 func_no,
>   }
>   
>   static int dw_pcie_ep_map_addr(struct pci_epc *epc, u8 func_no,
> -			       phys_addr_t addr,
> +			       phys_addr_t addr, int window,
>   			       u64 pci_addr, size_t size)
>   {
>   	int ret;
> @@ -367,6 +367,7 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
>   	unsigned int aligned_offset;
>   	u16 msg_ctrl, msg_data;
>   	u32 msg_addr_lower, msg_addr_upper, reg;
> +	int window = PCI_EPC_DEFAULT_WINDOW;
>   	u64 msg_addr;
>   	bool has_upper;
>   	int ret;
> @@ -390,11 +391,11 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
>   		reg = ep->msi_cap + PCI_MSI_DATA_32;
>   		msg_data = dw_pcie_readw_dbi(pci, reg);
>   	}
> -	aligned_offset = msg_addr_lower & (epc->mem->page_size - 1);
> +	aligned_offset = msg_addr_lower & (epc->mem[window]->page_size - 1);
>   	msg_addr = ((u64)msg_addr_upper) << 32 |
>   			(msg_addr_lower & ~aligned_offset);
> -	ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
> -				  epc->mem->page_size);
> +	ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
> +				  msg_addr, epc->mem[window]->page_size);
>   	if (ret)
>   		return ret;
>   
> @@ -416,6 +417,7 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>   	u32 reg, msg_data, vec_ctrl;
>   	u64 tbl_addr, msg_addr, reg_u64;
>   	void __iomem *msix_tbl;
> +	int window = PCI_EPC_DEFAULT_WINDOW;
>   	int ret;
>   
>   	reg = ep->msix_cap + PCI_MSIX_TABLE;
> @@ -452,8 +454,8 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>   		return -EPERM;
>   	}
>   
> -	ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
> -				  epc->mem->page_size);
> +	ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
> +				  msg_addr, epc->mem[window]->page_size);
>   	if (ret)
>   		return ret;
>   
> @@ -466,10 +468,11 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>   
>   void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
>   {
> +	int window = PCI_EPC_DEFAULT_WINDOW;
>   	struct pci_epc *epc = ep->epc;
>   
>   	pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
> -			      epc->mem->page_size);
> +			      epc->mem[window]->page_size);
>   
>   	pci_epc_mem_exit(epc);
>   }
> @@ -499,9 +502,12 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>   	u32 reg;
>   	void *addr;
>   	u8 hdr_type;
> +	int window;
>   	unsigned int nbars;
>   	unsigned int offset;
>   	struct pci_epc *epc;
> +	size_t msi_page_size;
> +	struct pci_epc_mem_window mem_window;
>   	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>   	struct device *dev = pci->dev;
>   	struct device_node *np = dev->of_node;
> @@ -574,15 +580,17 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>   	if (ret < 0)
>   		epc->max_functions = 1;
>   
> -	ret = __pci_epc_mem_init(epc, ep->phys_base, ep->addr_size,
> -				 ep->page_size);
> +	mem_window.phys_base = ep->phys_base;
> +	mem_window.size = ep->addr_size;
> +	ret = __pci_epc_mem_init(epc, &mem_window, 1, ep->page_size);
>   	if (ret < 0) {
>   		dev_err(dev, "Failed to initialize address space\n");
>   		return ret;
>   	}
>   
> -	ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys,
> -					     epc->mem->page_size);
> +	msi_page_size = epc->mem[PCI_EPC_DEFAULT_WINDOW]->page_size;
> +	ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys, &window,
> +					     msi_page_size, 0x0);
>   	if (!ep->msi_mem) {
>   		dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n");
>   		return -ENOMEM;
> diff --git a/drivers/pci/controller/pcie-cadence-ep.c b/drivers/pci/controller/pcie-cadence-ep.c
> index def7820..2410706 100644
> --- a/drivers/pci/controller/pcie-cadence-ep.c
> +++ b/drivers/pci/controller/pcie-cadence-ep.c
> @@ -172,7 +172,7 @@ static void cdns_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
>   }
>   
>   static int cdns_pcie_ep_map_addr(struct pci_epc *epc, u8 fn, phys_addr_t addr,
> -				 u64 pci_addr, size_t size)
> +				 int window, u64 pci_addr, size_t size)
>   {
>   	struct cdns_pcie_ep *ep = epc_get_drvdata(epc);
>   	struct cdns_pcie *pcie = &ep->pcie;
> @@ -434,12 +434,14 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
>   {
>   	struct device *dev = &pdev->dev;
>   	struct device_node *np = dev->of_node;
> +	struct pci_epc_mem_window mem_window;
>   	struct cdns_pcie_ep *ep;
>   	struct cdns_pcie *pcie;
>   	struct pci_epc *epc;
>   	struct resource *res;
>   	int ret;
>   	int phy_count;
> +	int window;
>   
>   	ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
>   	if (!ep)
> @@ -502,15 +504,16 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
>   	if (of_property_read_u8(np, "max-functions", &epc->max_functions) < 0)
>   		epc->max_functions = 1;
>   
> -	ret = pci_epc_mem_init(epc, pcie->mem_res->start,
> -			       resource_size(pcie->mem_res));
> +	mem_window.phys_base = pcie->mem_res->start;
> +	mem_window.size = resource_size(pcie->mem_res);
> +	ret = pci_epc_mem_init(epc, &mem_window, 1);
>   	if (ret < 0) {
>   		dev_err(dev, "failed to initialize the memory space\n");
>   		goto err_init;
>   	}
>   
>   	ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
> -						  SZ_128K);
> +						  &window, SZ_128K, 0x0);
>   	if (!ep->irq_cpu_addr) {
>   		dev_err(dev, "failed to reserve memory space for MSI\n");
>   		ret = -ENOMEM;
> diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
> index d743b0a..828052c 100644
> --- a/drivers/pci/controller/pcie-rockchip-ep.c
> +++ b/drivers/pci/controller/pcie-rockchip-ep.c
> @@ -256,8 +256,8 @@ static void rockchip_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
>   }
>   
>   static int rockchip_pcie_ep_map_addr(struct pci_epc *epc, u8 fn,
> -				     phys_addr_t addr, u64 pci_addr,
> -				     size_t size)
> +				     phys_addr_t addr, int window,
> +				     u64 pci_addr, size_t size)
>   {
>   	struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
>   	struct rockchip_pcie *pcie = &ep->rockchip;
> @@ -562,11 +562,13 @@ static const struct of_device_id rockchip_pcie_ep_of_match[] = {
>   
>   static int rockchip_pcie_ep_probe(struct platform_device *pdev)
>   {
> +	struct pci_epc_mem_window mem_window;
>   	struct device *dev = &pdev->dev;
>   	struct rockchip_pcie_ep *ep;
>   	struct rockchip_pcie *rockchip;
>   	struct pci_epc *epc;
>   	size_t max_regions;
> +	int window;
>   	int err;
>   
>   	ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
> @@ -614,15 +616,16 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
>   	/* Only enable function 0 by default */
>   	rockchip_pcie_write(rockchip, BIT(0), PCIE_CORE_PHY_FUNC_CFG);
>   
> -	err = pci_epc_mem_init(epc, rockchip->mem_res->start,
> -			       resource_size(rockchip->mem_res));
> +	mem_window.phys_base = rockchip->mem_res->start;
> +	mem_window.size = resource_size(rockchip->mem_res);
> +	err = pci_epc_mem_init(epc, &mem_window, 1);
>   	if (err < 0) {
>   		dev_err(dev, "failed to initialize the memory space\n");
>   		goto err_uninit_port;
>   	}
>   
>   	ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
> -						  SZ_128K);
> +						  &window, SZ_128K, 0x0);
>   	if (!ep->irq_cpu_addr) {
>   		dev_err(dev, "failed to reserve memory space for MSI\n");
>   		err = -ENOMEM;
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 1cfe368..4768d54 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -84,8 +84,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
>   	struct pci_epc *epc = epf->epc;
>   	enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>   	struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> -
> -	src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
> +	int window;
> +
> +	src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr,
> +					  &window, reg->size,
> +					  PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>   	if (!src_addr) {
>   		dev_err(dev, "Failed to allocate source address\n");
>   		reg->status = STATUS_SRC_ADDR_INVALID;
> @@ -93,15 +99,20 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
>   		goto err;
>   	}
>   
> -	ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, reg->src_addr,
> -			       reg->size);
> +	ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, window,
> +			       reg->src_addr, reg->size);
>   	if (ret) {
>   		dev_err(dev, "Failed to map source address\n");
>   		reg->status = STATUS_SRC_ADDR_INVALID;
>   		goto err_src_addr;
>   	}
>   
> -	dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr, reg->size);
> +	dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr,
> +					  &window, reg->size,
> +					  PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>   	if (!dst_addr) {
>   		dev_err(dev, "Failed to allocate destination address\n");
>   		reg->status = STATUS_DST_ADDR_INVALID;
> @@ -109,8 +120,8 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
>   		goto err_src_map_addr;
>   	}
>   
> -	ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, reg->dst_addr,
> -			       reg->size);
> +	ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, window,
> +			       reg->dst_addr, reg->size);
>   	if (ret) {
>   		dev_err(dev, "Failed to map destination address\n");
>   		reg->status = STATUS_DST_ADDR_INVALID;
> @@ -146,8 +157,13 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>   	struct pci_epc *epc = epf->epc;
>   	enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>   	struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> +	int window;
>   
> -	src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
> +	src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
> +					  PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>   	if (!src_addr) {
>   		dev_err(dev, "Failed to allocate address\n");
>   		reg->status = STATUS_SRC_ADDR_INVALID;
> @@ -155,8 +171,8 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>   		goto err;
>   	}
>   
> -	ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->src_addr,
> -			       reg->size);
> +	ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
> +			       reg->src_addr, reg->size);
>   	if (ret) {
>   		dev_err(dev, "Failed to map address\n");
>   		reg->status = STATUS_SRC_ADDR_INVALID;
> @@ -193,13 +209,18 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>   	void __iomem *dst_addr;
>   	void *buf;
>   	phys_addr_t phys_addr;
> +	int window;
>   	struct pci_epf *epf = epf_test->epf;
>   	struct device *dev = &epf->dev;
>   	struct pci_epc *epc = epf->epc;
>   	enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>   	struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
>   
> -	dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
> +	dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
> +					  PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> +					  PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>   	if (!dst_addr) {
>   		dev_err(dev, "Failed to allocate address\n");
>   		reg->status = STATUS_DST_ADDR_INVALID;
> @@ -207,8 +228,8 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>   		goto err;
>   	}
>   
> -	ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->dst_addr,
> -			       reg->size);
> +	ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
> +			       reg->dst_addr, reg->size);
>   	if (ret) {
>   		dev_err(dev, "Failed to map address\n");
>   		reg->status = STATUS_DST_ADDR_INVALID;
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 2091508..289c266 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -358,13 +358,15 @@ EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>    * @epc: the EPC device on which address is allocated
>    * @func_no: the endpoint function number in the EPC device
>    * @phys_addr: physical address of the local system
> + * @window: index to the window region where PCI address will be mapped
>    * @pci_addr: PCI address to which the physical address should be mapped
>    * @size: the size of the allocation
>    *
>    * Invoke to map CPU address with PCI address.
>    */
>   int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
> -		     phys_addr_t phys_addr, u64 pci_addr, size_t size)
> +		     phys_addr_t phys_addr, int window,
> +		     u64 pci_addr, size_t size)
>   {
>   	int ret;
>   	unsigned long flags;
> @@ -376,7 +378,8 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
>   		return 0;
>   
>   	spin_lock_irqsave(&epc->lock, flags);
> -	ret = epc->ops->map_addr(epc, func_no, phys_addr, pci_addr, size);
> +	ret = epc->ops->map_addr(epc, func_no, phys_addr,
> +				 window, pci_addr, size);
>   	spin_unlock_irqrestore(&epc->lock, flags);
>   
>   	return ret;
> diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
> index 2bf8bd1..4b610cd 100644
> --- a/drivers/pci/endpoint/pci-epc-mem.c
> +++ b/drivers/pci/endpoint/pci-epc-mem.c
> @@ -39,56 +39,78 @@ static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size)
>    * __pci_epc_mem_init() - initialize the pci_epc_mem structure
>    * @epc: the EPC device that invoked pci_epc_mem_init
>    * @phys_base: the physical address of the base
> - * @size: the size of the address space
> + * @num_windows: number of windows device supports
>    * @page_size: size of each page
>    *
>    * Invoke to initialize the pci_epc_mem structure used by the
>    * endpoint functions to allocate mapped PCI address.
>    */
> -int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
> -		       size_t page_size)
> +int __pci_epc_mem_init(struct pci_epc *epc, struct pci_epc_mem_window *windows,
> +		       int num_windows, size_t page_size)
>   {
> -	int ret;
> -	struct pci_epc_mem *mem;
> -	unsigned long *bitmap;
> +	struct pci_epc_mem *mem = NULL;
> +	unsigned long *bitmap = NULL;
>   	unsigned int page_shift;
> -	int pages;
>   	int bitmap_size;
> +	int pages;
> +	int ret;
> +	int i;
> +
> +	epc->mem_windows = 0;
> +
> +	if (!windows)
> +		return -EINVAL;
> +
> +	if (num_windows <= 0)
> +		return -EINVAL;
>   
>   	if (page_size < PAGE_SIZE)
>   		page_size = PAGE_SIZE;
>   
>   	page_shift = ilog2(page_size);
> -	pages = size >> page_shift;
> -	bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
>   
> -	mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> -	if (!mem) {
> -		ret = -ENOMEM;
> -		goto err;
> -	}
> +	epc->mem = kcalloc(num_windows, sizeof(*mem), GFP_KERNEL);
> +	if (!epc->mem)
> +		return -EINVAL;
>   
> -	bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> -	if (!bitmap) {
> -		ret = -ENOMEM;
> -		goto err_mem;
> -	}
> +	for (i = 0; i < num_windows; i++) {
> +		pages = windows[i].phys_base >> page_shift;
> +		bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
>   
> -	mem->bitmap = bitmap;
> -	mem->phys_base = phys_base;
> -	mem->page_size = page_size;
> -	mem->pages = pages;
> -	mem->size = size;
> +		mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> +		if (!mem) {
> +			ret = -ENOMEM;
> +			goto err_mem;
> +		}
>   
> -	epc->mem = mem;
> +		bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> +		if (!bitmap) {
> +			ret = -ENOMEM;
> +			goto err_mem;
> +		}
> +
> +		mem->bitmap = bitmap;
> +		mem->window.phys_base = windows[i].phys_base;
> +		mem->page_size = page_size;
> +		mem->pages = pages;
> +		mem->window.size = windows[i].size;
> +		mem->window.map_size = 0;
> +		mem->window.flags = windows[i].flags;
> +
> +		epc->mem[i] = mem;
> +	}
> +	epc->mem_windows = num_windows;
>   
>   	return 0;
>   
>   err_mem:
> -	kfree(mem);
> +	for (; i >= 0; i--) {
> +		kfree(mem->bitmap);
> +		kfree(epc->mem[i]);
> +	}
> +	kfree(epc->mem);
>   
> -err:
> -return ret;
> +	return ret;
>   }
>   EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
>   
> @@ -101,48 +123,152 @@ EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
>    */
>   void pci_epc_mem_exit(struct pci_epc *epc)
>   {
> -	struct pci_epc_mem *mem = epc->mem;
> +	struct pci_epc_mem *mem;
> +	int i;
> +
> +	if (!epc->mem_windows)
> +		return;
> +
> +	for (i = 0; i <= epc->mem_windows; i--) {
> +		mem = epc->mem[i];
> +		kfree(mem->bitmap);
> +		kfree(epc->mem[i]);
> +	}
> +	kfree(epc->mem);
>   
>   	epc->mem = NULL;
> -	kfree(mem->bitmap);
> -	kfree(mem);
> +	epc->mem_windows = 0;
>   }
>   EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
>   
> +static int pci_epc_find_best_fit_window(struct pci_epc *epc, size_t size,
> +					u32 flags)
> +{
> +	size_t window_least_size = 0;
> +	int best_fit_window = -1;
> +	struct pci_epc_mem *mem;
> +	size_t actual_size;
> +	size_t avail_size;
> +	u32 win_flags;
> +	int i;
> +
> +	for (i = 0; i < epc->mem_windows; i++) {
> +		mem = epc->mem[i];
> +		win_flags = mem->window.flags;
> +
> +		actual_size = ALIGN(size, mem->page_size);
> +		avail_size = mem->window.size - mem->window.map_size;
> +
> +		if (win_flags == 0x0) {
> +			if (best_fit_window == -1) {
> +				if (actual_size <= avail_size) {
> +					best_fit_window = i;
> +					window_least_size = mem->window.size;
> +				}
> +			} else {
> +				if (actual_size <= avail_size &&
> +				    mem->window.size < window_least_size) {
> +					best_fit_window = i;
> +					window_least_size = mem->window.size;
> +				}
> +			}
> +		} else {
> +			if (mem->window.map_size &&
> +			    (win_flags | PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC))
> +				continue;
> +
> +			if (!(win_flags | flags))
> +				continue;
> +
> +			if (best_fit_window == -1) {
> +				if (actual_size <= avail_size) {
> +					best_fit_window = i;
> +					window_least_size = mem->window.size;
> +				}
> +			} else {
> +				if (actual_size <= avail_size &&
> +				    mem->window.size < window_least_size) {
> +					best_fit_window = i;
> +					window_least_size = mem->window.size;
> +				}
> +			}
> +		}
> +	}
> +
> +	return best_fit_window;
> +}
> +
>   /**
>    * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
>    * @epc: the EPC device on which memory has to be allocated
>    * @phys_addr: populate the allocated physical address here
> + * @window: populate the window here which will be used to map PCI address
>    * @size: the size of the address space that has to be allocated
> + * @flags: look for window as requested in flags
>    *
>    * Invoke to allocate memory address from the EPC address space. This
>    * is usually done to map the remote RC address into the local system.
>    */
>   void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> -				     phys_addr_t *phys_addr, size_t size)
> +				     phys_addr_t *phys_addr,
> +				     int *window, size_t size, uint32_t flags)
>   {
> +	int best_fit = PCI_EPC_DEFAULT_WINDOW;
> +	void __iomem *virt_addr = NULL;
> +	struct pci_epc_mem *mem;
> +	unsigned int page_shift;
>   	int pageno;
> -	void __iomem *virt_addr;
> -	struct pci_epc_mem *mem = epc->mem;
> -	unsigned int page_shift = ilog2(mem->page_size);
>   	int order;
>   
> +	if (epc->mem_windows <= 0)
> +		return NULL;
> +
> +	if (epc->mem_windows > 1) {
> +		best_fit = pci_epc_find_best_fit_window(epc, size, flags);
> +		if (best_fit < 0)
> +			return NULL;
> +	}
> +
> +	mem = epc->mem[best_fit];
>   	size = ALIGN(size, mem->page_size);
> +	if (size > (mem->window.size - mem->window.map_size))
> +		return NULL;
> +	page_shift = ilog2(mem->page_size);
>   	order = pci_epc_mem_get_order(mem, size);
>   
>   	pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
>   	if (pageno < 0)
>   		return NULL;
>   
> -	*phys_addr = mem->phys_base + (pageno << page_shift);
> +	*phys_addr = mem->window.phys_base + (pageno << page_shift);
>   	virt_addr = ioremap(*phys_addr, size);
> -	if (!virt_addr)
> +	if (!virt_addr) {
>   		bitmap_release_region(mem->bitmap, pageno, order);
> +	} else {
> +		mem->window.map_size += size;
> +		*window = best_fit;
> +	}
>   
>   	return virt_addr;
>   }
>   EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
>   
> +static int pci_epc_get_matching_window(struct pci_epc *epc,
> +				       phys_addr_t phys_addr)
> +{
> +	struct pci_epc_mem *mem;
> +	int i;
> +
> +	for (i = 0; i < epc->mem_windows; i++) {
> +		mem = epc->mem[i];
> +
> +		if (mem->window.phys_base == phys_addr)
> +			return i;
> +	}
> +
> +	return -EINVAL;
> +}
> +
>   /**
>    * pci_epc_mem_free_addr() - free the allocated memory address
>    * @epc: the EPC device on which memory was allocated
> @@ -155,16 +281,26 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
>   void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
>   			   void __iomem *virt_addr, size_t size)
>   {
> +	struct pci_epc_mem *mem;
> +	unsigned int page_shift;
> +	int window = 0;
>   	int pageno;
> -	struct pci_epc_mem *mem = epc->mem;
> -	unsigned int page_shift = ilog2(mem->page_size);
>   	int order;
>   
> +	if (epc->mem_windows > 1) {
> +		window = pci_epc_get_matching_window(epc, phys_addr);
> +		if (window < 0)
> +			return;
> +	}
> +
> +	mem = epc->mem[window];
> +	page_shift = ilog2(mem->page_size);
>   	iounmap(virt_addr);
> -	pageno = (phys_addr - mem->phys_base) >> page_shift;
> +	pageno = (phys_addr - mem->window.phys_base) >> page_shift;
>   	size = ALIGN(size, mem->page_size);
>   	order = pci_epc_mem_get_order(mem, size);
>   	bitmap_release_region(mem->bitmap, pageno, order);
> +	mem->window.map_size -= size;
>   }
>   EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
>   
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index f641bad..bee6f65 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -48,7 +48,8 @@ struct pci_epc_ops {
>   	void	(*clear_bar)(struct pci_epc *epc, u8 func_no,
>   			     struct pci_epf_bar *epf_bar);
>   	int	(*map_addr)(struct pci_epc *epc, u8 func_no,
> -			    phys_addr_t addr, u64 pci_addr, size_t size);
> +			    phys_addr_t addr, int window,
> +			    u64 pci_addr, size_t size);
>   	void	(*unmap_addr)(struct pci_epc *epc, u8 func_no,
>   			      phys_addr_t addr);
>   	int	(*set_msi)(struct pci_epc *epc, u8 func_no, u8 interrupts);
> @@ -64,17 +65,57 @@ struct pci_epc_ops {
>   	struct module *owner;
>   };
>   
> +#define PCI_EPC_DEFAULT_WINDOW		0
> +
> +/**
> + * enum pci_epc_window_flags - flags info for pci_epc_mem_window
> + *
> + * This enum defines how the endpoint controller window should be used
> + * for allocations.
> + *
> + * @PCI_EPC_WINDOW_FLAG_MULTI_ALLOC: Indicates multiple chunks of memory can be
> + *				     allocated from same window
> + * @PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC: Indicates only single memory allocation
> + *					 is possible on the window

Instead of NON_MULTI_ALLOC, we could simply have different page_size for 
different windows. For a platform that doesn't allow multiple alloc, 
page size will be equal to the window size.
> + * @PCI_EPC_WINDOW_FLAG_LARGE_ALLOC: Window is used for large memory allocation
> + * @PCI_EPC_WINDOW_FLAG_SMALL_ALLOC: Window is used for small memory allocation
> + * @PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC: Window is used for high priority data
> + *					transfers
> + * @PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC: Window is used for low priority data
> + *				       transfers

Let's defer adding these flags until a platform actually starts to use this.

Thanks
Kishon

Hi Kishon,

On Mon, Dec 16, 2019 at 11:34 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>
> Hi Prabhakar,
>
> On 13/12/19 2:17 pm,  wrote:
> > From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > rcar pcie controller has support to map multiple memory regions
> > for mapping the outbound memory in local system, this feature
> > inspires to add support for handling such features in endpoint
> > framework. similar features exists on other controllers where
> > outbound regions can be specifically used for low/high priority
> > transactions, and regions can be flagged and used for allocation
> > of large/small memory allocations.
> > This patch adds support to handle such features, where the
> > properties described for outbound regions are used whenever a
> > request to memory is made.
> >
> > Signed-off-by: Lad, Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > ---
> >   drivers/pci/controller/dwc/pcie-designware-ep.c |  30 ++--
> >   drivers/pci/controller/pcie-cadence-ep.c        |  11 +-
> >   drivers/pci/controller/pcie-rockchip-ep.c       |  13 +-
> >   drivers/pci/endpoint/functions/pci-epf-test.c   |  47 ++++--
> >   drivers/pci/endpoint/pci-epc-core.c             |   7 +-
> >   drivers/pci/endpoint/pci-epc-mem.c              | 216 +++++++++++++++++++-----
> >   include/linux/pci-epc.h                         |  72 ++++++--
> >   7 files changed, 307 insertions(+), 89 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > index 3dd2e26..be6aa94 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > @@ -195,7 +195,7 @@ static void dw_pcie_ep_unmap_addr(struct pci_epc *epc, u8 func_no,
> >   }
> >
> >   static int dw_pcie_ep_map_addr(struct pci_epc *epc, u8 func_no,
> > -                            phys_addr_t addr,
> > +                            phys_addr_t addr, int window,
> >                              u64 pci_addr, size_t size)
> >   {
> >       int ret;
> > @@ -367,6 +367,7 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
> >       unsigned int aligned_offset;
> >       u16 msg_ctrl, msg_data;
> >       u32 msg_addr_lower, msg_addr_upper, reg;
> > +     int window = PCI_EPC_DEFAULT_WINDOW;
> >       u64 msg_addr;
> >       bool has_upper;
> >       int ret;
> > @@ -390,11 +391,11 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
> >               reg = ep->msi_cap + PCI_MSI_DATA_32;
> >               msg_data = dw_pcie_readw_dbi(pci, reg);
> >       }
> > -     aligned_offset = msg_addr_lower & (epc->mem->page_size - 1);
> > +     aligned_offset = msg_addr_lower & (epc->mem[window]->page_size - 1);
> >       msg_addr = ((u64)msg_addr_upper) << 32 |
> >                       (msg_addr_lower & ~aligned_offset);
> > -     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
> > -                               epc->mem->page_size);
> > +     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
> > +                               msg_addr, epc->mem[window]->page_size);
> >       if (ret)
> >               return ret;
> >
> > @@ -416,6 +417,7 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
> >       u32 reg, msg_data, vec_ctrl;
> >       u64 tbl_addr, msg_addr, reg_u64;
> >       void __iomem *msix_tbl;
> > +     int window = PCI_EPC_DEFAULT_WINDOW;
> >       int ret;
> >
> >       reg = ep->msix_cap + PCI_MSIX_TABLE;
> > @@ -452,8 +454,8 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
> >               return -EPERM;
> >       }
> >
> > -     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
> > -                               epc->mem->page_size);
> > +     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
> > +                               msg_addr, epc->mem[window]->page_size);
> >       if (ret)
> >               return ret;
> >
> > @@ -466,10 +468,11 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
> >
> >   void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
> >   {
> > +     int window = PCI_EPC_DEFAULT_WINDOW;
> >       struct pci_epc *epc = ep->epc;
> >
> >       pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
> > -                           epc->mem->page_size);
> > +                           epc->mem[window]->page_size);
> >
> >       pci_epc_mem_exit(epc);
> >   }
> > @@ -499,9 +502,12 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> >       u32 reg;
> >       void *addr;
> >       u8 hdr_type;
> > +     int window;
> >       unsigned int nbars;
> >       unsigned int offset;
> >       struct pci_epc *epc;
> > +     size_t msi_page_size;
> > +     struct pci_epc_mem_window mem_window;
> >       struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> >       struct device *dev = pci->dev;
> >       struct device_node *np = dev->of_node;
> > @@ -574,15 +580,17 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> >       if (ret < 0)
> >               epc->max_functions = 1;
> >
> > -     ret = __pci_epc_mem_init(epc, ep->phys_base, ep->addr_size,
> > -                              ep->page_size);
> > +     mem_window.phys_base = ep->phys_base;
> > +     mem_window.size = ep->addr_size;
> > +     ret = __pci_epc_mem_init(epc, &mem_window, 1, ep->page_size);
> >       if (ret < 0) {
> >               dev_err(dev, "Failed to initialize address space\n");
> >               return ret;
> >       }
> >
> > -     ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys,
> > -                                          epc->mem->page_size);
> > +     msi_page_size = epc->mem[PCI_EPC_DEFAULT_WINDOW]->page_size;
> > +     ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys, &window,
> > +                                          msi_page_size, 0x0);
> >       if (!ep->msi_mem) {
> >               dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n");
> >               return -ENOMEM;
> > diff --git a/drivers/pci/controller/pcie-cadence-ep.c b/drivers/pci/controller/pcie-cadence-ep.c
> > index def7820..2410706 100644
> > --- a/drivers/pci/controller/pcie-cadence-ep.c
> > +++ b/drivers/pci/controller/pcie-cadence-ep.c
> > @@ -172,7 +172,7 @@ static void cdns_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
> >   }
> >
> >   static int cdns_pcie_ep_map_addr(struct pci_epc *epc, u8 fn, phys_addr_t addr,
> > -                              u64 pci_addr, size_t size)
> > +                              int window, u64 pci_addr, size_t size)
> >   {
> >       struct cdns_pcie_ep *ep = epc_get_drvdata(epc);
> >       struct cdns_pcie *pcie = &ep->pcie;
> > @@ -434,12 +434,14 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
> >   {
> >       struct device *dev = &pdev->dev;
> >       struct device_node *np = dev->of_node;
> > +     struct pci_epc_mem_window mem_window;
> >       struct cdns_pcie_ep *ep;
> >       struct cdns_pcie *pcie;
> >       struct pci_epc *epc;
> >       struct resource *res;
> >       int ret;
> >       int phy_count;
> > +     int window;
> >
> >       ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
> >       if (!ep)
> > @@ -502,15 +504,16 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
> >       if (of_property_read_u8(np, "max-functions", &epc->max_functions) < 0)
> >               epc->max_functions = 1;
> >
> > -     ret = pci_epc_mem_init(epc, pcie->mem_res->start,
> > -                            resource_size(pcie->mem_res));
> > +     mem_window.phys_base = pcie->mem_res->start;
> > +     mem_window.size = resource_size(pcie->mem_res);
> > +     ret = pci_epc_mem_init(epc, &mem_window, 1);
> >       if (ret < 0) {
> >               dev_err(dev, "failed to initialize the memory space\n");
> >               goto err_init;
> >       }
> >
> >       ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
> > -                                               SZ_128K);
> > +                                               &window, SZ_128K, 0x0);
> >       if (!ep->irq_cpu_addr) {
> >               dev_err(dev, "failed to reserve memory space for MSI\n");
> >               ret = -ENOMEM;
> > diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
> > index d743b0a..828052c 100644
> > --- a/drivers/pci/controller/pcie-rockchip-ep.c
> > +++ b/drivers/pci/controller/pcie-rockchip-ep.c
> > @@ -256,8 +256,8 @@ static void rockchip_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
> >   }
> >
> >   static int rockchip_pcie_ep_map_addr(struct pci_epc *epc, u8 fn,
> > -                                  phys_addr_t addr, u64 pci_addr,
> > -                                  size_t size)
> > +                                  phys_addr_t addr, int window,
> > +                                  u64 pci_addr, size_t size)
> >   {
> >       struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
> >       struct rockchip_pcie *pcie = &ep->rockchip;
> > @@ -562,11 +562,13 @@ static const struct of_device_id rockchip_pcie_ep_of_match[] = {
> >
> >   static int rockchip_pcie_ep_probe(struct platform_device *pdev)
> >   {
> > +     struct pci_epc_mem_window mem_window;
> >       struct device *dev = &pdev->dev;
> >       struct rockchip_pcie_ep *ep;
> >       struct rockchip_pcie *rockchip;
> >       struct pci_epc *epc;
> >       size_t max_regions;
> > +     int window;
> >       int err;
> >
> >       ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
> > @@ -614,15 +616,16 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
> >       /* Only enable function 0 by default */
> >       rockchip_pcie_write(rockchip, BIT(0), PCIE_CORE_PHY_FUNC_CFG);
> >
> > -     err = pci_epc_mem_init(epc, rockchip->mem_res->start,
> > -                            resource_size(rockchip->mem_res));
> > +     mem_window.phys_base = rockchip->mem_res->start;
> > +     mem_window.size = resource_size(rockchip->mem_res);
> > +     err = pci_epc_mem_init(epc, &mem_window, 1);
> >       if (err < 0) {
> >               dev_err(dev, "failed to initialize the memory space\n");
> >               goto err_uninit_port;
> >       }
> >
> >       ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
> > -                                               SZ_128K);
> > +                                               &window, SZ_128K, 0x0);
> >       if (!ep->irq_cpu_addr) {
> >               dev_err(dev, "failed to reserve memory space for MSI\n");
> >               err = -ENOMEM;
> > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> > index 1cfe368..4768d54 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -84,8 +84,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
> >       struct pci_epc *epc = epf->epc;
> >       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> >       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> > -
> > -     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
> > +     int window;
> > +
> > +     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr,
> > +                                       &window, reg->size,
> > +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
> >       if (!src_addr) {
> >               dev_err(dev, "Failed to allocate source address\n");
> >               reg->status = STATUS_SRC_ADDR_INVALID;
> > @@ -93,15 +99,20 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
> >               goto err;
> >       }
> >
> > -     ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, reg->src_addr,
> > -                            reg->size);
> > +     ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, window,
> > +                            reg->src_addr, reg->size);
> >       if (ret) {
> >               dev_err(dev, "Failed to map source address\n");
> >               reg->status = STATUS_SRC_ADDR_INVALID;
> >               goto err_src_addr;
> >       }
> >
> > -     dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr, reg->size);
> > +     dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr,
> > +                                       &window, reg->size,
> > +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
> >       if (!dst_addr) {
> >               dev_err(dev, "Failed to allocate destination address\n");
> >               reg->status = STATUS_DST_ADDR_INVALID;
> > @@ -109,8 +120,8 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
> >               goto err_src_map_addr;
> >       }
> >
> > -     ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, reg->dst_addr,
> > -                            reg->size);
> > +     ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, window,
> > +                            reg->dst_addr, reg->size);
> >       if (ret) {
> >               dev_err(dev, "Failed to map destination address\n");
> >               reg->status = STATUS_DST_ADDR_INVALID;
> > @@ -146,8 +157,13 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
> >       struct pci_epc *epc = epf->epc;
> >       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> >       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> > +     int window;
> >
> > -     src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
> > +     src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
> > +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
> >       if (!src_addr) {
> >               dev_err(dev, "Failed to allocate address\n");
> >               reg->status = STATUS_SRC_ADDR_INVALID;
> > @@ -155,8 +171,8 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
> >               goto err;
> >       }
> >
> > -     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->src_addr,
> > -                            reg->size);
> > +     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
> > +                            reg->src_addr, reg->size);
> >       if (ret) {
> >               dev_err(dev, "Failed to map address\n");
> >               reg->status = STATUS_SRC_ADDR_INVALID;
> > @@ -193,13 +209,18 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> >       void __iomem *dst_addr;
> >       void *buf;
> >       phys_addr_t phys_addr;
> > +     int window;
> >       struct pci_epf *epf = epf_test->epf;
> >       struct device *dev = &epf->dev;
> >       struct pci_epc *epc = epf->epc;
> >       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> >       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> >
> > -     dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
> > +     dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
> > +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> > +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
> >       if (!dst_addr) {
> >               dev_err(dev, "Failed to allocate address\n");
> >               reg->status = STATUS_DST_ADDR_INVALID;
> > @@ -207,8 +228,8 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> >               goto err;
> >       }
> >
> > -     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->dst_addr,
> > -                            reg->size);
> > +     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
> > +                            reg->dst_addr, reg->size);
> >       if (ret) {
> >               dev_err(dev, "Failed to map address\n");
> >               reg->status = STATUS_DST_ADDR_INVALID;
> > diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> > index 2091508..289c266 100644
> > --- a/drivers/pci/endpoint/pci-epc-core.c
> > +++ b/drivers/pci/endpoint/pci-epc-core.c
> > @@ -358,13 +358,15 @@ EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
> >    * @epc: the EPC device on which address is allocated
> >    * @func_no: the endpoint function number in the EPC device
> >    * @phys_addr: physical address of the local system
> > + * @window: index to the window region where PCI address will be mapped
> >    * @pci_addr: PCI address to which the physical address should be mapped
> >    * @size: the size of the allocation
> >    *
> >    * Invoke to map CPU address with PCI address.
> >    */
> >   int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
> > -                  phys_addr_t phys_addr, u64 pci_addr, size_t size)
> > +                  phys_addr_t phys_addr, int window,
> > +                  u64 pci_addr, size_t size)
> >   {
> >       int ret;
> >       unsigned long flags;
> > @@ -376,7 +378,8 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
> >               return 0;
> >
> >       spin_lock_irqsave(&epc->lock, flags);
> > -     ret = epc->ops->map_addr(epc, func_no, phys_addr, pci_addr, size);
> > +     ret = epc->ops->map_addr(epc, func_no, phys_addr,
> > +                              window, pci_addr, size);
> >       spin_unlock_irqrestore(&epc->lock, flags);
> >
> >       return ret;
> > diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
> > index 2bf8bd1..4b610cd 100644
> > --- a/drivers/pci/endpoint/pci-epc-mem.c
> > +++ b/drivers/pci/endpoint/pci-epc-mem.c
> > @@ -39,56 +39,78 @@ static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size)
> >    * __pci_epc_mem_init() - initialize the pci_epc_mem structure
> >    * @epc: the EPC device that invoked pci_epc_mem_init
> >    * @phys_base: the physical address of the base
> > - * @size: the size of the address space
> > + * @num_windows: number of windows device supports
> >    * @page_size: size of each page
> >    *
> >    * Invoke to initialize the pci_epc_mem structure used by the
> >    * endpoint functions to allocate mapped PCI address.
> >    */
> > -int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
> > -                    size_t page_size)
> > +int __pci_epc_mem_init(struct pci_epc *epc, struct pci_epc_mem_window *windows,
> > +                    int num_windows, size_t page_size)
> >   {
> > -     int ret;
> > -     struct pci_epc_mem *mem;
> > -     unsigned long *bitmap;
> > +     struct pci_epc_mem *mem = NULL;
> > +     unsigned long *bitmap = NULL;
> >       unsigned int page_shift;
> > -     int pages;
> >       int bitmap_size;
> > +     int pages;
> > +     int ret;
> > +     int i;
> > +
> > +     epc->mem_windows = 0;
> > +
> > +     if (!windows)
> > +             return -EINVAL;
> > +
> > +     if (num_windows <= 0)
> > +             return -EINVAL;
> >
> >       if (page_size < PAGE_SIZE)
> >               page_size = PAGE_SIZE;
> >
> >       page_shift = ilog2(page_size);
> > -     pages = size >> page_shift;
> > -     bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
> >
> > -     mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> > -     if (!mem) {
> > -             ret = -ENOMEM;
> > -             goto err;
> > -     }
> > +     epc->mem = kcalloc(num_windows, sizeof(*mem), GFP_KERNEL);
> > +     if (!epc->mem)
> > +             return -EINVAL;
> >
> > -     bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> > -     if (!bitmap) {
> > -             ret = -ENOMEM;
> > -             goto err_mem;
> > -     }
> > +     for (i = 0; i < num_windows; i++) {
> > +             pages = windows[i].phys_base >> page_shift;
> > +             bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
> >
> > -     mem->bitmap = bitmap;
> > -     mem->phys_base = phys_base;
> > -     mem->page_size = page_size;
> > -     mem->pages = pages;
> > -     mem->size = size;
> > +             mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> > +             if (!mem) {
> > +                     ret = -ENOMEM;
> > +                     goto err_mem;
> > +             }
> >
> > -     epc->mem = mem;
> > +             bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> > +             if (!bitmap) {
> > +                     ret = -ENOMEM;
> > +                     goto err_mem;
> > +             }
> > +
> > +             mem->bitmap = bitmap;
> > +             mem->window.phys_base = windows[i].phys_base;
> > +             mem->page_size = page_size;
> > +             mem->pages = pages;
> > +             mem->window.size = windows[i].size;
> > +             mem->window.map_size = 0;
> > +             mem->window.flags = windows[i].flags;
> > +
> > +             epc->mem[i] = mem;
> > +     }
> > +     epc->mem_windows = num_windows;
> >
> >       return 0;
> >
> >   err_mem:
> > -     kfree(mem);
> > +     for (; i >= 0; i--) {
> > +             kfree(mem->bitmap);
> > +             kfree(epc->mem[i]);
> > +     }
> > +     kfree(epc->mem);
> >
> > -err:
> > -return ret;
> > +     return ret;
> >   }
> >   EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
> >
> > @@ -101,48 +123,152 @@ EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
> >    */
> >   void pci_epc_mem_exit(struct pci_epc *epc)
> >   {
> > -     struct pci_epc_mem *mem = epc->mem;
> > +     struct pci_epc_mem *mem;
> > +     int i;
> > +
> > +     if (!epc->mem_windows)
> > +             return;
> > +
> > +     for (i = 0; i <= epc->mem_windows; i--) {
> > +             mem = epc->mem[i];
> > +             kfree(mem->bitmap);
> > +             kfree(epc->mem[i]);
> > +     }
> > +     kfree(epc->mem);
> >
> >       epc->mem = NULL;
> > -     kfree(mem->bitmap);
> > -     kfree(mem);
> > +     epc->mem_windows = 0;
> >   }
> >   EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
> >
> > +static int pci_epc_find_best_fit_window(struct pci_epc *epc, size_t size,
> > +                                     u32 flags)
> > +{
> > +     size_t window_least_size = 0;
> > +     int best_fit_window = -1;
> > +     struct pci_epc_mem *mem;
> > +     size_t actual_size;
> > +     size_t avail_size;
> > +     u32 win_flags;
> > +     int i;
> > +
> > +     for (i = 0; i < epc->mem_windows; i++) {
> > +             mem = epc->mem[i];
> > +             win_flags = mem->window.flags;
> > +
> > +             actual_size = ALIGN(size, mem->page_size);
> > +             avail_size = mem->window.size - mem->window.map_size;
> > +
> > +             if (win_flags == 0x0) {
> > +                     if (best_fit_window == -1) {
> > +                             if (actual_size <= avail_size) {
> > +                                     best_fit_window = i;
> > +                                     window_least_size = mem->window.size;
> > +                             }
> > +                     } else {
> > +                             if (actual_size <= avail_size &&
> > +                                 mem->window.size < window_least_size) {
> > +                                     best_fit_window = i;
> > +                                     window_least_size = mem->window.size;
> > +                             }
> > +                     }
> > +             } else {
> > +                     if (mem->window.map_size &&
> > +                         (win_flags | PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC))
> > +                             continue;
> > +
> > +                     if (!(win_flags | flags))
> > +                             continue;
> > +
> > +                     if (best_fit_window == -1) {
> > +                             if (actual_size <= avail_size) {
> > +                                     best_fit_window = i;
> > +                                     window_least_size = mem->window.size;
> > +                             }
> > +                     } else {
> > +                             if (actual_size <= avail_size &&
> > +                                 mem->window.size < window_least_size) {
> > +                                     best_fit_window = i;
> > +                                     window_least_size = mem->window.size;
> > +                             }
> > +                     }
> > +             }
> > +     }
> > +
> > +     return best_fit_window;
> > +}
> > +
> >   /**
> >    * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
> >    * @epc: the EPC device on which memory has to be allocated
> >    * @phys_addr: populate the allocated physical address here
> > + * @window: populate the window here which will be used to map PCI address
> >    * @size: the size of the address space that has to be allocated
> > + * @flags: look for window as requested in flags
> >    *
> >    * Invoke to allocate memory address from the EPC address space. This
> >    * is usually done to map the remote RC address into the local system.
> >    */
> >   void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> > -                                  phys_addr_t *phys_addr, size_t size)
> > +                                  phys_addr_t *phys_addr,
> > +                                  int *window, size_t size, uint32_t flags)
> >   {
> > +     int best_fit = PCI_EPC_DEFAULT_WINDOW;
> > +     void __iomem *virt_addr = NULL;
> > +     struct pci_epc_mem *mem;
> > +     unsigned int page_shift;
> >       int pageno;
> > -     void __iomem *virt_addr;
> > -     struct pci_epc_mem *mem = epc->mem;
> > -     unsigned int page_shift = ilog2(mem->page_size);
> >       int order;
> >
> > +     if (epc->mem_windows <= 0)
> > +             return NULL;
> > +
> > +     if (epc->mem_windows > 1) {
> > +             best_fit = pci_epc_find_best_fit_window(epc, size, flags);
> > +             if (best_fit < 0)
> > +                     return NULL;
> > +     }
> > +
> > +     mem = epc->mem[best_fit];
> >       size = ALIGN(size, mem->page_size);
> > +     if (size > (mem->window.size - mem->window.map_size))
> > +             return NULL;
> > +     page_shift = ilog2(mem->page_size);
> >       order = pci_epc_mem_get_order(mem, size);
> >
> >       pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
> >       if (pageno < 0)
> >               return NULL;
> >
> > -     *phys_addr = mem->phys_base + (pageno << page_shift);
> > +     *phys_addr = mem->window.phys_base + (pageno << page_shift);
> >       virt_addr = ioremap(*phys_addr, size);
> > -     if (!virt_addr)
> > +     if (!virt_addr) {
> >               bitmap_release_region(mem->bitmap, pageno, order);
> > +     } else {
> > +             mem->window.map_size += size;
> > +             *window = best_fit;
> > +     }
> >
> >       return virt_addr;
> >   }
> >   EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
> >
> > +static int pci_epc_get_matching_window(struct pci_epc *epc,
> > +                                    phys_addr_t phys_addr)
> > +{
> > +     struct pci_epc_mem *mem;
> > +     int i;
> > +
> > +     for (i = 0; i < epc->mem_windows; i++) {
> > +             mem = epc->mem[i];
> > +
> > +             if (mem->window.phys_base == phys_addr)
> > +                     return i;
> > +     }
> > +
> > +     return -EINVAL;
> > +}
> > +
> >   /**
> >    * pci_epc_mem_free_addr() - free the allocated memory address
> >    * @epc: the EPC device on which memory was allocated
> > @@ -155,16 +281,26 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
> >   void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
> >                          void __iomem *virt_addr, size_t size)
> >   {
> > +     struct pci_epc_mem *mem;
> > +     unsigned int page_shift;
> > +     int window = 0;
> >       int pageno;
> > -     struct pci_epc_mem *mem = epc->mem;
> > -     unsigned int page_shift = ilog2(mem->page_size);
> >       int order;
> >
> > +     if (epc->mem_windows > 1) {
> > +             window = pci_epc_get_matching_window(epc, phys_addr);
> > +             if (window < 0)
> > +                     return;
> > +     }
> > +
> > +     mem = epc->mem[window];
> > +     page_shift = ilog2(mem->page_size);
> >       iounmap(virt_addr);
> > -     pageno = (phys_addr - mem->phys_base) >> page_shift;
> > +     pageno = (phys_addr - mem->window.phys_base) >> page_shift;
> >       size = ALIGN(size, mem->page_size);
> >       order = pci_epc_mem_get_order(mem, size);
> >       bitmap_release_region(mem->bitmap, pageno, order);
> > +     mem->window.map_size -= size;
> >   }
> >   EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
> >
> > diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> > index f641bad..bee6f65 100644
> > --- a/include/linux/pci-epc.h
> > +++ b/include/linux/pci-epc.h
> > @@ -48,7 +48,8 @@ struct pci_epc_ops {
> >       void    (*clear_bar)(struct pci_epc *epc, u8 func_no,
> >                            struct pci_epf_bar *epf_bar);
> >       int     (*map_addr)(struct pci_epc *epc, u8 func_no,
> > -                         phys_addr_t addr, u64 pci_addr, size_t size);
> > +                         phys_addr_t addr, int window,
> > +                         u64 pci_addr, size_t size);
> >       void    (*unmap_addr)(struct pci_epc *epc, u8 func_no,
> >                             phys_addr_t addr);
> >       int     (*set_msi)(struct pci_epc *epc, u8 func_no, u8 interrupts);
> > @@ -64,17 +65,57 @@ struct pci_epc_ops {
> >       struct module *owner;
> >   };
> >
> > +#define PCI_EPC_DEFAULT_WINDOW               0
> > +
> > +/**
> > + * enum pci_epc_window_flags - flags info for pci_epc_mem_window
> > + *
> > + * This enum defines how the endpoint controller window should be used
> > + * for allocations.
> > + *
> > + * @PCI_EPC_WINDOW_FLAG_MULTI_ALLOC: Indicates multiple chunks of memory can be
> > + *                                allocated from same window
> > + * @PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC: Indicates only single memory allocation
> > + *                                    is possible on the window
>
> Instead of NON_MULTI_ALLOC, we could simply have different page_size for
> different windows. For a platform that doesn't allow multiple alloc,
> page size will be equal to the window size.
>
I would still prefer this flag and not go with page size = window size
as we could allocate unnecessary memory
that might not be used and also the window sizes might be too large.

> > + * @PCI_EPC_WINDOW_FLAG_LARGE_ALLOC: Window is used for large memory allocation
> > + * @PCI_EPC_WINDOW_FLAG_SMALL_ALLOC: Window is used for small memory allocation
> > + * @PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC: Window is used for high priority data
> > + *                                   transfers
> > + * @PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC: Window is used for low priority data
> > + *                                  transfers
>
> Let's defer adding these flags until a platform actually starts to use this.
>
sure will drop the above.

Cheers,
--Prabhakar

> Thanks
> Kishon

Hi Prabhakar,

On 18/12/19 10:53 PM, Lad, Prabhakar wrote:
> Hi Kishon,
> 
> On Mon, Dec 16, 2019 at 11:34 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>>
>> Hi Prabhakar,
>>
>> On 13/12/19 2:17 pm,  wrote:
>>> From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>
>>>
>>> rcar pcie controller has support to map multiple memory regions
>>> for mapping the outbound memory in local system, this feature
>>> inspires to add support for handling such features in endpoint
>>> framework. similar features exists on other controllers where
>>> outbound regions can be specifically used for low/high priority
>>> transactions, and regions can be flagged and used for allocation
>>> of large/small memory allocations.
>>> This patch adds support to handle such features, where the
>>> properties described for outbound regions are used whenever a
>>> request to memory is made.
>>>
>>> Signed-off-by: Lad, Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>>> ---
>>>   drivers/pci/controller/dwc/pcie-designware-ep.c |  30 ++--
>>>   drivers/pci/controller/pcie-cadence-ep.c        |  11 +-
>>>   drivers/pci/controller/pcie-rockchip-ep.c       |  13 +-
>>>   drivers/pci/endpoint/functions/pci-epf-test.c   |  47 ++++--
>>>   drivers/pci/endpoint/pci-epc-core.c             |   7 +-
>>>   drivers/pci/endpoint/pci-epc-mem.c              | 216 +++++++++++++++++++-----
>>>   include/linux/pci-epc.h                         |  72 ++++++--
>>>   7 files changed, 307 insertions(+), 89 deletions(-)
>>>
>>> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> index 3dd2e26..be6aa94 100644
>>> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> @@ -195,7 +195,7 @@ static void dw_pcie_ep_unmap_addr(struct pci_epc *epc, u8 func_no,
>>>   }
>>>
>>>   static int dw_pcie_ep_map_addr(struct pci_epc *epc, u8 func_no,
>>> -                            phys_addr_t addr,
>>> +                            phys_addr_t addr, int window,
>>>                              u64 pci_addr, size_t size)
>>>   {
>>>       int ret;
>>> @@ -367,6 +367,7 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>       unsigned int aligned_offset;
>>>       u16 msg_ctrl, msg_data;
>>>       u32 msg_addr_lower, msg_addr_upper, reg;
>>> +     int window = PCI_EPC_DEFAULT_WINDOW;
>>>       u64 msg_addr;
>>>       bool has_upper;
>>>       int ret;
>>> @@ -390,11 +391,11 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>               reg = ep->msi_cap + PCI_MSI_DATA_32;
>>>               msg_data = dw_pcie_readw_dbi(pci, reg);
>>>       }
>>> -     aligned_offset = msg_addr_lower & (epc->mem->page_size - 1);
>>> +     aligned_offset = msg_addr_lower & (epc->mem[window]->page_size - 1);
>>>       msg_addr = ((u64)msg_addr_upper) << 32 |
>>>                       (msg_addr_lower & ~aligned_offset);
>>> -     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
>>> -                               epc->mem->page_size);
>>> +     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
>>> +                               msg_addr, epc->mem[window]->page_size);
>>>       if (ret)
>>>               return ret;
>>>
>>> @@ -416,6 +417,7 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>       u32 reg, msg_data, vec_ctrl;
>>>       u64 tbl_addr, msg_addr, reg_u64;
>>>       void __iomem *msix_tbl;
>>> +     int window = PCI_EPC_DEFAULT_WINDOW;
>>>       int ret;
>>>
>>>       reg = ep->msix_cap + PCI_MSIX_TABLE;
>>> @@ -452,8 +454,8 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>               return -EPERM;
>>>       }
>>>
>>> -     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
>>> -                               epc->mem->page_size);
>>> +     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
>>> +                               msg_addr, epc->mem[window]->page_size);
>>>       if (ret)
>>>               return ret;
>>>
>>> @@ -466,10 +468,11 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>
>>>   void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
>>>   {
>>> +     int window = PCI_EPC_DEFAULT_WINDOW;
>>>       struct pci_epc *epc = ep->epc;
>>>
>>>       pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
>>> -                           epc->mem->page_size);
>>> +                           epc->mem[window]->page_size);
>>>
>>>       pci_epc_mem_exit(epc);
>>>   }
>>> @@ -499,9 +502,12 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>>>       u32 reg;
>>>       void *addr;
>>>       u8 hdr_type;
>>> +     int window;
>>>       unsigned int nbars;
>>>       unsigned int offset;
>>>       struct pci_epc *epc;
>>> +     size_t msi_page_size;
>>> +     struct pci_epc_mem_window mem_window;
>>>       struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>>       struct device *dev = pci->dev;
>>>       struct device_node *np = dev->of_node;
>>> @@ -574,15 +580,17 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>>>       if (ret < 0)
>>>               epc->max_functions = 1;
>>>
>>> -     ret = __pci_epc_mem_init(epc, ep->phys_base, ep->addr_size,
>>> -                              ep->page_size);
>>> +     mem_window.phys_base = ep->phys_base;
>>> +     mem_window.size = ep->addr_size;
>>> +     ret = __pci_epc_mem_init(epc, &mem_window, 1, ep->page_size);
>>>       if (ret < 0) {
>>>               dev_err(dev, "Failed to initialize address space\n");
>>>               return ret;
>>>       }
>>>
>>> -     ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys,
>>> -                                          epc->mem->page_size);
>>> +     msi_page_size = epc->mem[PCI_EPC_DEFAULT_WINDOW]->page_size;
>>> +     ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys, &window,
>>> +                                          msi_page_size, 0x0);
>>>       if (!ep->msi_mem) {
>>>               dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n");
>>>               return -ENOMEM;
>>> diff --git a/drivers/pci/controller/pcie-cadence-ep.c b/drivers/pci/controller/pcie-cadence-ep.c
>>> index def7820..2410706 100644
>>> --- a/drivers/pci/controller/pcie-cadence-ep.c
>>> +++ b/drivers/pci/controller/pcie-cadence-ep.c
>>> @@ -172,7 +172,7 @@ static void cdns_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
>>>   }
>>>
>>>   static int cdns_pcie_ep_map_addr(struct pci_epc *epc, u8 fn, phys_addr_t addr,
>>> -                              u64 pci_addr, size_t size)
>>> +                              int window, u64 pci_addr, size_t size)
>>>   {
>>>       struct cdns_pcie_ep *ep = epc_get_drvdata(epc);
>>>       struct cdns_pcie *pcie = &ep->pcie;
>>> @@ -434,12 +434,14 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
>>>   {
>>>       struct device *dev = &pdev->dev;
>>>       struct device_node *np = dev->of_node;
>>> +     struct pci_epc_mem_window mem_window;
>>>       struct cdns_pcie_ep *ep;
>>>       struct cdns_pcie *pcie;
>>>       struct pci_epc *epc;
>>>       struct resource *res;
>>>       int ret;
>>>       int phy_count;
>>> +     int window;
>>>
>>>       ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
>>>       if (!ep)
>>> @@ -502,15 +504,16 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
>>>       if (of_property_read_u8(np, "max-functions", &epc->max_functions) < 0)
>>>               epc->max_functions = 1;
>>>
>>> -     ret = pci_epc_mem_init(epc, pcie->mem_res->start,
>>> -                            resource_size(pcie->mem_res));
>>> +     mem_window.phys_base = pcie->mem_res->start;
>>> +     mem_window.size = resource_size(pcie->mem_res);
>>> +     ret = pci_epc_mem_init(epc, &mem_window, 1);
>>>       if (ret < 0) {
>>>               dev_err(dev, "failed to initialize the memory space\n");
>>>               goto err_init;
>>>       }
>>>
>>>       ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
>>> -                                               SZ_128K);
>>> +                                               &window, SZ_128K, 0x0);
>>>       if (!ep->irq_cpu_addr) {
>>>               dev_err(dev, "failed to reserve memory space for MSI\n");
>>>               ret = -ENOMEM;
>>> diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
>>> index d743b0a..828052c 100644
>>> --- a/drivers/pci/controller/pcie-rockchip-ep.c
>>> +++ b/drivers/pci/controller/pcie-rockchip-ep.c
>>> @@ -256,8 +256,8 @@ static void rockchip_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
>>>   }
>>>
>>>   static int rockchip_pcie_ep_map_addr(struct pci_epc *epc, u8 fn,
>>> -                                  phys_addr_t addr, u64 pci_addr,
>>> -                                  size_t size)
>>> +                                  phys_addr_t addr, int window,
>>> +                                  u64 pci_addr, size_t size)
>>>   {
>>>       struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
>>>       struct rockchip_pcie *pcie = &ep->rockchip;
>>> @@ -562,11 +562,13 @@ static const struct of_device_id rockchip_pcie_ep_of_match[] = {
>>>
>>>   static int rockchip_pcie_ep_probe(struct platform_device *pdev)
>>>   {
>>> +     struct pci_epc_mem_window mem_window;
>>>       struct device *dev = &pdev->dev;
>>>       struct rockchip_pcie_ep *ep;
>>>       struct rockchip_pcie *rockchip;
>>>       struct pci_epc *epc;
>>>       size_t max_regions;
>>> +     int window;
>>>       int err;
>>>
>>>       ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
>>> @@ -614,15 +616,16 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
>>>       /* Only enable function 0 by default */
>>>       rockchip_pcie_write(rockchip, BIT(0), PCIE_CORE_PHY_FUNC_CFG);
>>>
>>> -     err = pci_epc_mem_init(epc, rockchip->mem_res->start,
>>> -                            resource_size(rockchip->mem_res));
>>> +     mem_window.phys_base = rockchip->mem_res->start;
>>> +     mem_window.size = resource_size(rockchip->mem_res);
>>> +     err = pci_epc_mem_init(epc, &mem_window, 1);
>>>       if (err < 0) {
>>>               dev_err(dev, "failed to initialize the memory space\n");
>>>               goto err_uninit_port;
>>>       }
>>>
>>>       ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
>>> -                                               SZ_128K);
>>> +                                               &window, SZ_128K, 0x0);
>>>       if (!ep->irq_cpu_addr) {
>>>               dev_err(dev, "failed to reserve memory space for MSI\n");
>>>               err = -ENOMEM;
>>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> index 1cfe368..4768d54 100644
>>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> @@ -84,8 +84,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
>>>       struct pci_epc *epc = epf->epc;
>>>       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>>>       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
>>> -
>>> -     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
>>> +     int window;
>>> +
>>> +     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr,
>>> +                                       &window, reg->size,
>>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>>>       if (!src_addr) {
>>>               dev_err(dev, "Failed to allocate source address\n");
>>>               reg->status = STATUS_SRC_ADDR_INVALID;
>>> @@ -93,15 +99,20 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
>>>               goto err;
>>>       }
>>>
>>> -     ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, reg->src_addr,
>>> -                            reg->size);
>>> +     ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, window,
>>> +                            reg->src_addr, reg->size);
>>>       if (ret) {
>>>               dev_err(dev, "Failed to map source address\n");
>>>               reg->status = STATUS_SRC_ADDR_INVALID;
>>>               goto err_src_addr;
>>>       }
>>>
>>> -     dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr, reg->size);
>>> +     dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr,
>>> +                                       &window, reg->size,
>>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>>>       if (!dst_addr) {
>>>               dev_err(dev, "Failed to allocate destination address\n");
>>>               reg->status = STATUS_DST_ADDR_INVALID;
>>> @@ -109,8 +120,8 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
>>>               goto err_src_map_addr;
>>>       }
>>>
>>> -     ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, reg->dst_addr,
>>> -                            reg->size);
>>> +     ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, window,
>>> +                            reg->dst_addr, reg->size);
>>>       if (ret) {
>>>               dev_err(dev, "Failed to map destination address\n");
>>>               reg->status = STATUS_DST_ADDR_INVALID;
>>> @@ -146,8 +157,13 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>>>       struct pci_epc *epc = epf->epc;
>>>       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>>>       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
>>> +     int window;
>>>
>>> -     src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
>>> +     src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
>>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>>>       if (!src_addr) {
>>>               dev_err(dev, "Failed to allocate address\n");
>>>               reg->status = STATUS_SRC_ADDR_INVALID;
>>> @@ -155,8 +171,8 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>>>               goto err;
>>>       }
>>>
>>> -     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->src_addr,
>>> -                            reg->size);
>>> +     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
>>> +                            reg->src_addr, reg->size);
>>>       if (ret) {
>>>               dev_err(dev, "Failed to map address\n");
>>>               reg->status = STATUS_SRC_ADDR_INVALID;
>>> @@ -193,13 +209,18 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>>>       void __iomem *dst_addr;
>>>       void *buf;
>>>       phys_addr_t phys_addr;
>>> +     int window;
>>>       struct pci_epf *epf = epf_test->epf;
>>>       struct device *dev = &epf->dev;
>>>       struct pci_epc *epc = epf->epc;
>>>       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>>>       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
>>>
>>> -     dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
>>> +     dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
>>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>>>       if (!dst_addr) {
>>>               dev_err(dev, "Failed to allocate address\n");
>>>               reg->status = STATUS_DST_ADDR_INVALID;
>>> @@ -207,8 +228,8 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>>>               goto err;
>>>       }
>>>
>>> -     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->dst_addr,
>>> -                            reg->size);
>>> +     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
>>> +                            reg->dst_addr, reg->size);
>>>       if (ret) {
>>>               dev_err(dev, "Failed to map address\n");
>>>               reg->status = STATUS_DST_ADDR_INVALID;
>>> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
>>> index 2091508..289c266 100644
>>> --- a/drivers/pci/endpoint/pci-epc-core.c
>>> +++ b/drivers/pci/endpoint/pci-epc-core.c
>>> @@ -358,13 +358,15 @@ EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>>>    * @epc: the EPC device on which address is allocated
>>>    * @func_no: the endpoint function number in the EPC device
>>>    * @phys_addr: physical address of the local system
>>> + * @window: index to the window region where PCI address will be mapped
>>>    * @pci_addr: PCI address to which the physical address should be mapped
>>>    * @size: the size of the allocation
>>>    *
>>>    * Invoke to map CPU address with PCI address.
>>>    */
>>>   int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
>>> -                  phys_addr_t phys_addr, u64 pci_addr, size_t size)
>>> +                  phys_addr_t phys_addr, int window,
>>> +                  u64 pci_addr, size_t size)
>>>   {
>>>       int ret;
>>>       unsigned long flags;
>>> @@ -376,7 +378,8 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
>>>               return 0;
>>>
>>>       spin_lock_irqsave(&epc->lock, flags);
>>> -     ret = epc->ops->map_addr(epc, func_no, phys_addr, pci_addr, size);
>>> +     ret = epc->ops->map_addr(epc, func_no, phys_addr,
>>> +                              window, pci_addr, size);
>>>       spin_unlock_irqrestore(&epc->lock, flags);
>>>
>>>       return ret;
>>> diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
>>> index 2bf8bd1..4b610cd 100644
>>> --- a/drivers/pci/endpoint/pci-epc-mem.c
>>> +++ b/drivers/pci/endpoint/pci-epc-mem.c
>>> @@ -39,56 +39,78 @@ static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size)
>>>    * __pci_epc_mem_init() - initialize the pci_epc_mem structure
>>>    * @epc: the EPC device that invoked pci_epc_mem_init
>>>    * @phys_base: the physical address of the base
>>> - * @size: the size of the address space
>>> + * @num_windows: number of windows device supports
>>>    * @page_size: size of each page
>>>    *
>>>    * Invoke to initialize the pci_epc_mem structure used by the
>>>    * endpoint functions to allocate mapped PCI address.
>>>    */
>>> -int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
>>> -                    size_t page_size)
>>> +int __pci_epc_mem_init(struct pci_epc *epc, struct pci_epc_mem_window *windows,
>>> +                    int num_windows, size_t page_size)
>>>   {
>>> -     int ret;
>>> -     struct pci_epc_mem *mem;
>>> -     unsigned long *bitmap;
>>> +     struct pci_epc_mem *mem = NULL;
>>> +     unsigned long *bitmap = NULL;
>>>       unsigned int page_shift;
>>> -     int pages;
>>>       int bitmap_size;
>>> +     int pages;
>>> +     int ret;
>>> +     int i;
>>> +
>>> +     epc->mem_windows = 0;
>>> +
>>> +     if (!windows)
>>> +             return -EINVAL;
>>> +
>>> +     if (num_windows <= 0)
>>> +             return -EINVAL;
>>>
>>>       if (page_size < PAGE_SIZE)
>>>               page_size = PAGE_SIZE;
>>>
>>>       page_shift = ilog2(page_size);
>>> -     pages = size >> page_shift;
>>> -     bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
>>>
>>> -     mem = kzalloc(sizeof(*mem), GFP_KERNEL);
>>> -     if (!mem) {
>>> -             ret = -ENOMEM;
>>> -             goto err;
>>> -     }
>>> +     epc->mem = kcalloc(num_windows, sizeof(*mem), GFP_KERNEL);
>>> +     if (!epc->mem)
>>> +             return -EINVAL;
>>>
>>> -     bitmap = kzalloc(bitmap_size, GFP_KERNEL);
>>> -     if (!bitmap) {
>>> -             ret = -ENOMEM;
>>> -             goto err_mem;
>>> -     }
>>> +     for (i = 0; i < num_windows; i++) {
>>> +             pages = windows[i].phys_base >> page_shift;
>>> +             bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
>>>
>>> -     mem->bitmap = bitmap;
>>> -     mem->phys_base = phys_base;
>>> -     mem->page_size = page_size;
>>> -     mem->pages = pages;
>>> -     mem->size = size;
>>> +             mem = kzalloc(sizeof(*mem), GFP_KERNEL);
>>> +             if (!mem) {
>>> +                     ret = -ENOMEM;
>>> +                     goto err_mem;
>>> +             }
>>>
>>> -     epc->mem = mem;
>>> +             bitmap = kzalloc(bitmap_size, GFP_KERNEL);
>>> +             if (!bitmap) {
>>> +                     ret = -ENOMEM;
>>> +                     goto err_mem;
>>> +             }
>>> +
>>> +             mem->bitmap = bitmap;
>>> +             mem->window.phys_base = windows[i].phys_base;
>>> +             mem->page_size = page_size;
>>> +             mem->pages = pages;
>>> +             mem->window.size = windows[i].size;
>>> +             mem->window.map_size = 0;
>>> +             mem->window.flags = windows[i].flags;
>>> +
>>> +             epc->mem[i] = mem;
>>> +     }
>>> +     epc->mem_windows = num_windows;
>>>
>>>       return 0;
>>>
>>>   err_mem:
>>> -     kfree(mem);
>>> +     for (; i >= 0; i--) {
>>> +             kfree(mem->bitmap);
>>> +             kfree(epc->mem[i]);
>>> +     }
>>> +     kfree(epc->mem);
>>>
>>> -err:
>>> -return ret;
>>> +     return ret;
>>>   }
>>>   EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
>>>
>>> @@ -101,48 +123,152 @@ EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
>>>    */
>>>   void pci_epc_mem_exit(struct pci_epc *epc)
>>>   {
>>> -     struct pci_epc_mem *mem = epc->mem;
>>> +     struct pci_epc_mem *mem;
>>> +     int i;
>>> +
>>> +     if (!epc->mem_windows)
>>> +             return;
>>> +
>>> +     for (i = 0; i <= epc->mem_windows; i--) {
>>> +             mem = epc->mem[i];
>>> +             kfree(mem->bitmap);
>>> +             kfree(epc->mem[i]);
>>> +     }
>>> +     kfree(epc->mem);
>>>
>>>       epc->mem = NULL;
>>> -     kfree(mem->bitmap);
>>> -     kfree(mem);
>>> +     epc->mem_windows = 0;
>>>   }
>>>   EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
>>>
>>> +static int pci_epc_find_best_fit_window(struct pci_epc *epc, size_t size,
>>> +                                     u32 flags)
>>> +{
>>> +     size_t window_least_size = 0;
>>> +     int best_fit_window = -1;
>>> +     struct pci_epc_mem *mem;
>>> +     size_t actual_size;
>>> +     size_t avail_size;
>>> +     u32 win_flags;
>>> +     int i;
>>> +
>>> +     for (i = 0; i < epc->mem_windows; i++) {
>>> +             mem = epc->mem[i];
>>> +             win_flags = mem->window.flags;
>>> +
>>> +             actual_size = ALIGN(size, mem->page_size);
>>> +             avail_size = mem->window.size - mem->window.map_size;
>>> +
>>> +             if (win_flags == 0x0) {
>>> +                     if (best_fit_window == -1) {
>>> +                             if (actual_size <= avail_size) {
>>> +                                     best_fit_window = i;
>>> +                                     window_least_size = mem->window.size;
>>> +                             }
>>> +                     } else {
>>> +                             if (actual_size <= avail_size &&
>>> +                                 mem->window.size < window_least_size) {
>>> +                                     best_fit_window = i;
>>> +                                     window_least_size = mem->window.size;
>>> +                             }
>>> +                     }
>>> +             } else {
>>> +                     if (mem->window.map_size &&
>>> +                         (win_flags | PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC))
>>> +                             continue;
>>> +
>>> +                     if (!(win_flags | flags))
>>> +                             continue;
>>> +
>>> +                     if (best_fit_window == -1) {
>>> +                             if (actual_size <= avail_size) {
>>> +                                     best_fit_window = i;
>>> +                                     window_least_size = mem->window.size;
>>> +                             }
>>> +                     } else {
>>> +                             if (actual_size <= avail_size &&
>>> +                                 mem->window.size < window_least_size) {
>>> +                                     best_fit_window = i;
>>> +                                     window_least_size = mem->window.size;
>>> +                             }
>>> +                     }
>>> +             }
>>> +     }
>>> +
>>> +     return best_fit_window;
>>> +}
>>> +
>>>   /**
>>>    * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
>>>    * @epc: the EPC device on which memory has to be allocated
>>>    * @phys_addr: populate the allocated physical address here
>>> + * @window: populate the window here which will be used to map PCI address
>>>    * @size: the size of the address space that has to be allocated
>>> + * @flags: look for window as requested in flags
>>>    *
>>>    * Invoke to allocate memory address from the EPC address space. This
>>>    * is usually done to map the remote RC address into the local system.
>>>    */
>>>   void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
>>> -                                  phys_addr_t *phys_addr, size_t size)
>>> +                                  phys_addr_t *phys_addr,
>>> +                                  int *window, size_t size, uint32_t flags)
>>>   {
>>> +     int best_fit = PCI_EPC_DEFAULT_WINDOW;
>>> +     void __iomem *virt_addr = NULL;
>>> +     struct pci_epc_mem *mem;
>>> +     unsigned int page_shift;
>>>       int pageno;
>>> -     void __iomem *virt_addr;
>>> -     struct pci_epc_mem *mem = epc->mem;
>>> -     unsigned int page_shift = ilog2(mem->page_size);
>>>       int order;
>>>
>>> +     if (epc->mem_windows <= 0)
>>> +             return NULL;
>>> +
>>> +     if (epc->mem_windows > 1) {
>>> +             best_fit = pci_epc_find_best_fit_window(epc, size, flags);
>>> +             if (best_fit < 0)
>>> +                     return NULL;
>>> +     }
>>> +
>>> +     mem = epc->mem[best_fit];
>>>       size = ALIGN(size, mem->page_size);
>>> +     if (size > (mem->window.size - mem->window.map_size))
>>> +             return NULL;
>>> +     page_shift = ilog2(mem->page_size);
>>>       order = pci_epc_mem_get_order(mem, size);
>>>
>>>       pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
>>>       if (pageno < 0)
>>>               return NULL;
>>>
>>> -     *phys_addr = mem->phys_base + (pageno << page_shift);
>>> +     *phys_addr = mem->window.phys_base + (pageno << page_shift);
>>>       virt_addr = ioremap(*phys_addr, size);
>>> -     if (!virt_addr)
>>> +     if (!virt_addr) {
>>>               bitmap_release_region(mem->bitmap, pageno, order);
>>> +     } else {
>>> +             mem->window.map_size += size;
>>> +             *window = best_fit;
>>> +     }
>>>
>>>       return virt_addr;
>>>   }
>>>   EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
>>>
>>> +static int pci_epc_get_matching_window(struct pci_epc *epc,
>>> +                                    phys_addr_t phys_addr)
>>> +{
>>> +     struct pci_epc_mem *mem;
>>> +     int i;
>>> +
>>> +     for (i = 0; i < epc->mem_windows; i++) {
>>> +             mem = epc->mem[i];
>>> +
>>> +             if (mem->window.phys_base == phys_addr)
>>> +                     return i;
>>> +     }
>>> +
>>> +     return -EINVAL;
>>> +}
>>> +
>>>   /**
>>>    * pci_epc_mem_free_addr() - free the allocated memory address
>>>    * @epc: the EPC device on which memory was allocated
>>> @@ -155,16 +281,26 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
>>>   void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
>>>                          void __iomem *virt_addr, size_t size)
>>>   {
>>> +     struct pci_epc_mem *mem;
>>> +     unsigned int page_shift;
>>> +     int window = 0;
>>>       int pageno;
>>> -     struct pci_epc_mem *mem = epc->mem;
>>> -     unsigned int page_shift = ilog2(mem->page_size);
>>>       int order;
>>>
>>> +     if (epc->mem_windows > 1) {
>>> +             window = pci_epc_get_matching_window(epc, phys_addr);
>>> +             if (window < 0)
>>> +                     return;
>>> +     }
>>> +
>>> +     mem = epc->mem[window];
>>> +     page_shift = ilog2(mem->page_size);
>>>       iounmap(virt_addr);
>>> -     pageno = (phys_addr - mem->phys_base) >> page_shift;
>>> +     pageno = (phys_addr - mem->window.phys_base) >> page_shift;
>>>       size = ALIGN(size, mem->page_size);
>>>       order = pci_epc_mem_get_order(mem, size);
>>>       bitmap_release_region(mem->bitmap, pageno, order);
>>> +     mem->window.map_size -= size;
>>>   }
>>>   EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
>>>
>>> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
>>> index f641bad..bee6f65 100644
>>> --- a/include/linux/pci-epc.h
>>> +++ b/include/linux/pci-epc.h
>>> @@ -48,7 +48,8 @@ struct pci_epc_ops {
>>>       void    (*clear_bar)(struct pci_epc *epc, u8 func_no,
>>>                            struct pci_epf_bar *epf_bar);
>>>       int     (*map_addr)(struct pci_epc *epc, u8 func_no,
>>> -                         phys_addr_t addr, u64 pci_addr, size_t size);
>>> +                         phys_addr_t addr, int window,
>>> +                         u64 pci_addr, size_t size);
>>>       void    (*unmap_addr)(struct pci_epc *epc, u8 func_no,
>>>                             phys_addr_t addr);
>>>       int     (*set_msi)(struct pci_epc *epc, u8 func_no, u8 interrupts);
>>> @@ -64,17 +65,57 @@ struct pci_epc_ops {
>>>       struct module *owner;
>>>   };
>>>
>>> +#define PCI_EPC_DEFAULT_WINDOW               0
>>> +
>>> +/**
>>> + * enum pci_epc_window_flags - flags info for pci_epc_mem_window
>>> + *
>>> + * This enum defines how the endpoint controller window should be used
>>> + * for allocations.
>>> + *
>>> + * @PCI_EPC_WINDOW_FLAG_MULTI_ALLOC: Indicates multiple chunks of memory can be
>>> + *                                allocated from same window
>>> + * @PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC: Indicates only single memory allocation
>>> + *                                    is possible on the window
>>
>> Instead of NON_MULTI_ALLOC, we could simply have different page_size for
>> different windows. For a platform that doesn't allow multiple alloc,
>> page size will be equal to the window size.
>>
> I would still prefer this flag and not go with page size = window size
> as we could allocate unnecessary memory

Nor sure I understand you here. If you have
PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC, wouldn't it mean, you cannot have
more than 1 allocation in the entire window. Setting page size same as
window size will also mean the same thing.
> that might not be used and also the window sizes might be too large.

IMHO We could still have flags to provide a type for a window and
directing the allocation to a particular window with a type. But
at-least for the use case that you are trying to solve, it's simpler to
have page_size = window_size and the allocation algorithm need not change.

Thanks
Kishon

Hi Kishon,

On Thu, Jan 2, 2020 at 9:43 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>
> Hi Prabhakar,
>
> On 18/12/19 10:53 PM, Lad, Prabhakar wrote:
> > Hi Kishon,
> >
> > On Mon, Dec 16, 2019 at 11:34 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
> >>
> >> Hi Prabhakar,
> >>
> >> On 13/12/19 2:17 pm,  wrote:
> >>> From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >>>
> >>> rcar pcie controller has support to map multiple memory regions
> >>> for mapping the outbound memory in local system, this feature
> >>> inspires to add support for handling such features in endpoint
> >>> framework. similar features exists on other controllers where
> >>> outbound regions can be specifically used for low/high priority
> >>> transactions, and regions can be flagged and used for allocation
> >>> of large/small memory allocations.
> >>> This patch adds support to handle such features, where the
> >>> properties described for outbound regions are used whenever a
> >>> request to memory is made.
> >>>
> >>> Signed-off-by: Lad, Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >>> ---
> >>>   drivers/pci/controller/dwc/pcie-designware-ep.c |  30 ++--
> >>>   drivers/pci/controller/pcie-cadence-ep.c        |  11 +-
> >>>   drivers/pci/controller/pcie-rockchip-ep.c       |  13 +-
> >>>   drivers/pci/endpoint/functions/pci-epf-test.c   |  47 ++++--
> >>>   drivers/pci/endpoint/pci-epc-core.c             |   7 +-
> >>>   drivers/pci/endpoint/pci-epc-mem.c              | 216 +++++++++++++++++++-----
> >>>   include/linux/pci-epc.h                         |  72 ++++++--
> >>>   7 files changed, 307 insertions(+), 89 deletions(-)
> >>>
> >>> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> >>> index 3dd2e26..be6aa94 100644
> >>> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> >>> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> >>> @@ -195,7 +195,7 @@ static void dw_pcie_ep_unmap_addr(struct pci_epc *epc, u8 func_no,
> >>>   }
> >>>
> >>>   static int dw_pcie_ep_map_addr(struct pci_epc *epc, u8 func_no,
> >>> -                            phys_addr_t addr,
> >>> +                            phys_addr_t addr, int window,
> >>>                              u64 pci_addr, size_t size)
> >>>   {
> >>>       int ret;
> >>> @@ -367,6 +367,7 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
> >>>       unsigned int aligned_offset;
> >>>       u16 msg_ctrl, msg_data;
> >>>       u32 msg_addr_lower, msg_addr_upper, reg;
> >>> +     int window = PCI_EPC_DEFAULT_WINDOW;
> >>>       u64 msg_addr;
> >>>       bool has_upper;
> >>>       int ret;
> >>> @@ -390,11 +391,11 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
> >>>               reg = ep->msi_cap + PCI_MSI_DATA_32;
> >>>               msg_data = dw_pcie_readw_dbi(pci, reg);
> >>>       }
> >>> -     aligned_offset = msg_addr_lower & (epc->mem->page_size - 1);
> >>> +     aligned_offset = msg_addr_lower & (epc->mem[window]->page_size - 1);
> >>>       msg_addr = ((u64)msg_addr_upper) << 32 |
> >>>                       (msg_addr_lower & ~aligned_offset);
> >>> -     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
> >>> -                               epc->mem->page_size);
> >>> +     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
> >>> +                               msg_addr, epc->mem[window]->page_size);
> >>>       if (ret)
> >>>               return ret;
> >>>
> >>> @@ -416,6 +417,7 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
> >>>       u32 reg, msg_data, vec_ctrl;
> >>>       u64 tbl_addr, msg_addr, reg_u64;
> >>>       void __iomem *msix_tbl;
> >>> +     int window = PCI_EPC_DEFAULT_WINDOW;
> >>>       int ret;
> >>>
> >>>       reg = ep->msix_cap + PCI_MSIX_TABLE;
> >>> @@ -452,8 +454,8 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
> >>>               return -EPERM;
> >>>       }
> >>>
> >>> -     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
> >>> -                               epc->mem->page_size);
> >>> +     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
> >>> +                               msg_addr, epc->mem[window]->page_size);
> >>>       if (ret)
> >>>               return ret;
> >>>
> >>> @@ -466,10 +468,11 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
> >>>
> >>>   void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
> >>>   {
> >>> +     int window = PCI_EPC_DEFAULT_WINDOW;
> >>>       struct pci_epc *epc = ep->epc;
> >>>
> >>>       pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
> >>> -                           epc->mem->page_size);
> >>> +                           epc->mem[window]->page_size);
> >>>
> >>>       pci_epc_mem_exit(epc);
> >>>   }
> >>> @@ -499,9 +502,12 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> >>>       u32 reg;
> >>>       void *addr;
> >>>       u8 hdr_type;
> >>> +     int window;
> >>>       unsigned int nbars;
> >>>       unsigned int offset;
> >>>       struct pci_epc *epc;
> >>> +     size_t msi_page_size;
> >>> +     struct pci_epc_mem_window mem_window;
> >>>       struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> >>>       struct device *dev = pci->dev;
> >>>       struct device_node *np = dev->of_node;
> >>> @@ -574,15 +580,17 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> >>>       if (ret < 0)
> >>>               epc->max_functions = 1;
> >>>
> >>> -     ret = __pci_epc_mem_init(epc, ep->phys_base, ep->addr_size,
> >>> -                              ep->page_size);
> >>> +     mem_window.phys_base = ep->phys_base;
> >>> +     mem_window.size = ep->addr_size;
> >>> +     ret = __pci_epc_mem_init(epc, &mem_window, 1, ep->page_size);
> >>>       if (ret < 0) {
> >>>               dev_err(dev, "Failed to initialize address space\n");
> >>>               return ret;
> >>>       }
> >>>
> >>> -     ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys,
> >>> -                                          epc->mem->page_size);
> >>> +     msi_page_size = epc->mem[PCI_EPC_DEFAULT_WINDOW]->page_size;
> >>> +     ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys, &window,
> >>> +                                          msi_page_size, 0x0);
> >>>       if (!ep->msi_mem) {
> >>>               dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n");
> >>>               return -ENOMEM;
> >>> diff --git a/drivers/pci/controller/pcie-cadence-ep.c b/drivers/pci/controller/pcie-cadence-ep.c
> >>> index def7820..2410706 100644
> >>> --- a/drivers/pci/controller/pcie-cadence-ep.c
> >>> +++ b/drivers/pci/controller/pcie-cadence-ep.c
> >>> @@ -172,7 +172,7 @@ static void cdns_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
> >>>   }
> >>>
> >>>   static int cdns_pcie_ep_map_addr(struct pci_epc *epc, u8 fn, phys_addr_t addr,
> >>> -                              u64 pci_addr, size_t size)
> >>> +                              int window, u64 pci_addr, size_t size)
> >>>   {
> >>>       struct cdns_pcie_ep *ep = epc_get_drvdata(epc);
> >>>       struct cdns_pcie *pcie = &ep->pcie;
> >>> @@ -434,12 +434,14 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
> >>>   {
> >>>       struct device *dev = &pdev->dev;
> >>>       struct device_node *np = dev->of_node;
> >>> +     struct pci_epc_mem_window mem_window;
> >>>       struct cdns_pcie_ep *ep;
> >>>       struct cdns_pcie *pcie;
> >>>       struct pci_epc *epc;
> >>>       struct resource *res;
> >>>       int ret;
> >>>       int phy_count;
> >>> +     int window;
> >>>
> >>>       ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
> >>>       if (!ep)
> >>> @@ -502,15 +504,16 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
> >>>       if (of_property_read_u8(np, "max-functions", &epc->max_functions) < 0)
> >>>               epc->max_functions = 1;
> >>>
> >>> -     ret = pci_epc_mem_init(epc, pcie->mem_res->start,
> >>> -                            resource_size(pcie->mem_res));
> >>> +     mem_window.phys_base = pcie->mem_res->start;
> >>> +     mem_window.size = resource_size(pcie->mem_res);
> >>> +     ret = pci_epc_mem_init(epc, &mem_window, 1);
> >>>       if (ret < 0) {
> >>>               dev_err(dev, "failed to initialize the memory space\n");
> >>>               goto err_init;
> >>>       }
> >>>
> >>>       ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
> >>> -                                               SZ_128K);
> >>> +                                               &window, SZ_128K, 0x0);
> >>>       if (!ep->irq_cpu_addr) {
> >>>               dev_err(dev, "failed to reserve memory space for MSI\n");
> >>>               ret = -ENOMEM;
> >>> diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
> >>> index d743b0a..828052c 100644
> >>> --- a/drivers/pci/controller/pcie-rockchip-ep.c
> >>> +++ b/drivers/pci/controller/pcie-rockchip-ep.c
> >>> @@ -256,8 +256,8 @@ static void rockchip_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
> >>>   }
> >>>
> >>>   static int rockchip_pcie_ep_map_addr(struct pci_epc *epc, u8 fn,
> >>> -                                  phys_addr_t addr, u64 pci_addr,
> >>> -                                  size_t size)
> >>> +                                  phys_addr_t addr, int window,
> >>> +                                  u64 pci_addr, size_t size)
> >>>   {
> >>>       struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
> >>>       struct rockchip_pcie *pcie = &ep->rockchip;
> >>> @@ -562,11 +562,13 @@ static const struct of_device_id rockchip_pcie_ep_of_match[] = {
> >>>
> >>>   static int rockchip_pcie_ep_probe(struct platform_device *pdev)
> >>>   {
> >>> +     struct pci_epc_mem_window mem_window;
> >>>       struct device *dev = &pdev->dev;
> >>>       struct rockchip_pcie_ep *ep;
> >>>       struct rockchip_pcie *rockchip;
> >>>       struct pci_epc *epc;
> >>>       size_t max_regions;
> >>> +     int window;
> >>>       int err;
> >>>
> >>>       ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
> >>> @@ -614,15 +616,16 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
> >>>       /* Only enable function 0 by default */
> >>>       rockchip_pcie_write(rockchip, BIT(0), PCIE_CORE_PHY_FUNC_CFG);
> >>>
> >>> -     err = pci_epc_mem_init(epc, rockchip->mem_res->start,
> >>> -                            resource_size(rockchip->mem_res));
> >>> +     mem_window.phys_base = rockchip->mem_res->start;
> >>> +     mem_window.size = resource_size(rockchip->mem_res);
> >>> +     err = pci_epc_mem_init(epc, &mem_window, 1);
> >>>       if (err < 0) {
> >>>               dev_err(dev, "failed to initialize the memory space\n");
> >>>               goto err_uninit_port;
> >>>       }
> >>>
> >>>       ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
> >>> -                                               SZ_128K);
> >>> +                                               &window, SZ_128K, 0x0);
> >>>       if (!ep->irq_cpu_addr) {
> >>>               dev_err(dev, "failed to reserve memory space for MSI\n");
> >>>               err = -ENOMEM;
> >>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> >>> index 1cfe368..4768d54 100644
> >>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> >>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> >>> @@ -84,8 +84,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
> >>>       struct pci_epc *epc = epf->epc;
> >>>       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> >>>       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> >>> -
> >>> -     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
> >>> +     int window;
> >>> +
> >>> +     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr,
> >>> +                                       &window, reg->size,
> >>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
> >>>       if (!src_addr) {
> >>>               dev_err(dev, "Failed to allocate source address\n");
> >>>               reg->status = STATUS_SRC_ADDR_INVALID;
> >>> @@ -93,15 +99,20 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
> >>>               goto err;
> >>>       }
> >>>
> >>> -     ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, reg->src_addr,
> >>> -                            reg->size);
> >>> +     ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, window,
> >>> +                            reg->src_addr, reg->size);
> >>>       if (ret) {
> >>>               dev_err(dev, "Failed to map source address\n");
> >>>               reg->status = STATUS_SRC_ADDR_INVALID;
> >>>               goto err_src_addr;
> >>>       }
> >>>
> >>> -     dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr, reg->size);
> >>> +     dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr,
> >>> +                                       &window, reg->size,
> >>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
> >>>       if (!dst_addr) {
> >>>               dev_err(dev, "Failed to allocate destination address\n");
> >>>               reg->status = STATUS_DST_ADDR_INVALID;
> >>> @@ -109,8 +120,8 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
> >>>               goto err_src_map_addr;
> >>>       }
> >>>
> >>> -     ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, reg->dst_addr,
> >>> -                            reg->size);
> >>> +     ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, window,
> >>> +                            reg->dst_addr, reg->size);
> >>>       if (ret) {
> >>>               dev_err(dev, "Failed to map destination address\n");
> >>>               reg->status = STATUS_DST_ADDR_INVALID;
> >>> @@ -146,8 +157,13 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
> >>>       struct pci_epc *epc = epf->epc;
> >>>       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> >>>       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> >>> +     int window;
> >>>
> >>> -     src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
> >>> +     src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
> >>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
> >>>       if (!src_addr) {
> >>>               dev_err(dev, "Failed to allocate address\n");
> >>>               reg->status = STATUS_SRC_ADDR_INVALID;
> >>> @@ -155,8 +171,8 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
> >>>               goto err;
> >>>       }
> >>>
> >>> -     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->src_addr,
> >>> -                            reg->size);
> >>> +     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
> >>> +                            reg->src_addr, reg->size);
> >>>       if (ret) {
> >>>               dev_err(dev, "Failed to map address\n");
> >>>               reg->status = STATUS_SRC_ADDR_INVALID;
> >>> @@ -193,13 +209,18 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> >>>       void __iomem *dst_addr;
> >>>       void *buf;
> >>>       phys_addr_t phys_addr;
> >>> +     int window;
> >>>       struct pci_epf *epf = epf_test->epf;
> >>>       struct device *dev = &epf->dev;
> >>>       struct pci_epc *epc = epf->epc;
> >>>       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> >>>       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> >>>
> >>> -     dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
> >>> +     dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
> >>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
> >>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
> >>>       if (!dst_addr) {
> >>>               dev_err(dev, "Failed to allocate address\n");
> >>>               reg->status = STATUS_DST_ADDR_INVALID;
> >>> @@ -207,8 +228,8 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> >>>               goto err;
> >>>       }
> >>>
> >>> -     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->dst_addr,
> >>> -                            reg->size);
> >>> +     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
> >>> +                            reg->dst_addr, reg->size);
> >>>       if (ret) {
> >>>               dev_err(dev, "Failed to map address\n");
> >>>               reg->status = STATUS_DST_ADDR_INVALID;
> >>> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> >>> index 2091508..289c266 100644
> >>> --- a/drivers/pci/endpoint/pci-epc-core.c
> >>> +++ b/drivers/pci/endpoint/pci-epc-core.c
> >>> @@ -358,13 +358,15 @@ EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
> >>>    * @epc: the EPC device on which address is allocated
> >>>    * @func_no: the endpoint function number in the EPC device
> >>>    * @phys_addr: physical address of the local system
> >>> + * @window: index to the window region where PCI address will be mapped
> >>>    * @pci_addr: PCI address to which the physical address should be mapped
> >>>    * @size: the size of the allocation
> >>>    *
> >>>    * Invoke to map CPU address with PCI address.
> >>>    */
> >>>   int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
> >>> -                  phys_addr_t phys_addr, u64 pci_addr, size_t size)
> >>> +                  phys_addr_t phys_addr, int window,
> >>> +                  u64 pci_addr, size_t size)
> >>>   {
> >>>       int ret;
> >>>       unsigned long flags;
> >>> @@ -376,7 +378,8 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
> >>>               return 0;
> >>>
> >>>       spin_lock_irqsave(&epc->lock, flags);
> >>> -     ret = epc->ops->map_addr(epc, func_no, phys_addr, pci_addr, size);
> >>> +     ret = epc->ops->map_addr(epc, func_no, phys_addr,
> >>> +                              window, pci_addr, size);
> >>>       spin_unlock_irqrestore(&epc->lock, flags);
> >>>
> >>>       return ret;
> >>> diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
> >>> index 2bf8bd1..4b610cd 100644
> >>> --- a/drivers/pci/endpoint/pci-epc-mem.c
> >>> +++ b/drivers/pci/endpoint/pci-epc-mem.c
> >>> @@ -39,56 +39,78 @@ static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size)
> >>>    * __pci_epc_mem_init() - initialize the pci_epc_mem structure
> >>>    * @epc: the EPC device that invoked pci_epc_mem_init
> >>>    * @phys_base: the physical address of the base
> >>> - * @size: the size of the address space
> >>> + * @num_windows: number of windows device supports
> >>>    * @page_size: size of each page
> >>>    *
> >>>    * Invoke to initialize the pci_epc_mem structure used by the
> >>>    * endpoint functions to allocate mapped PCI address.
> >>>    */
> >>> -int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
> >>> -                    size_t page_size)
> >>> +int __pci_epc_mem_init(struct pci_epc *epc, struct pci_epc_mem_window *windows,
> >>> +                    int num_windows, size_t page_size)
> >>>   {
> >>> -     int ret;
> >>> -     struct pci_epc_mem *mem;
> >>> -     unsigned long *bitmap;
> >>> +     struct pci_epc_mem *mem = NULL;
> >>> +     unsigned long *bitmap = NULL;
> >>>       unsigned int page_shift;
> >>> -     int pages;
> >>>       int bitmap_size;
> >>> +     int pages;
> >>> +     int ret;
> >>> +     int i;
> >>> +
> >>> +     epc->mem_windows = 0;
> >>> +
> >>> +     if (!windows)
> >>> +             return -EINVAL;
> >>> +
> >>> +     if (num_windows <= 0)
> >>> +             return -EINVAL;
> >>>
> >>>       if (page_size < PAGE_SIZE)
> >>>               page_size = PAGE_SIZE;
> >>>
> >>>       page_shift = ilog2(page_size);
> >>> -     pages = size >> page_shift;
> >>> -     bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
> >>>
> >>> -     mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> >>> -     if (!mem) {
> >>> -             ret = -ENOMEM;
> >>> -             goto err;
> >>> -     }
> >>> +     epc->mem = kcalloc(num_windows, sizeof(*mem), GFP_KERNEL);
> >>> +     if (!epc->mem)
> >>> +             return -EINVAL;
> >>>
> >>> -     bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> >>> -     if (!bitmap) {
> >>> -             ret = -ENOMEM;
> >>> -             goto err_mem;
> >>> -     }
> >>> +     for (i = 0; i < num_windows; i++) {
> >>> +             pages = windows[i].phys_base >> page_shift;
> >>> +             bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
> >>>
> >>> -     mem->bitmap = bitmap;
> >>> -     mem->phys_base = phys_base;
> >>> -     mem->page_size = page_size;
> >>> -     mem->pages = pages;
> >>> -     mem->size = size;
> >>> +             mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> >>> +             if (!mem) {
> >>> +                     ret = -ENOMEM;
> >>> +                     goto err_mem;
> >>> +             }
> >>>
> >>> -     epc->mem = mem;
> >>> +             bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> >>> +             if (!bitmap) {
> >>> +                     ret = -ENOMEM;
> >>> +                     goto err_mem;
> >>> +             }
> >>> +
> >>> +             mem->bitmap = bitmap;
> >>> +             mem->window.phys_base = windows[i].phys_base;
> >>> +             mem->page_size = page_size;
> >>> +             mem->pages = pages;
> >>> +             mem->window.size = windows[i].size;
> >>> +             mem->window.map_size = 0;
> >>> +             mem->window.flags = windows[i].flags;
> >>> +
> >>> +             epc->mem[i] = mem;
> >>> +     }
> >>> +     epc->mem_windows = num_windows;
> >>>
> >>>       return 0;
> >>>
> >>>   err_mem:
> >>> -     kfree(mem);
> >>> +     for (; i >= 0; i--) {
> >>> +             kfree(mem->bitmap);
> >>> +             kfree(epc->mem[i]);
> >>> +     }
> >>> +     kfree(epc->mem);
> >>>
> >>> -err:
> >>> -return ret;
> >>> +     return ret;
> >>>   }
> >>>   EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
> >>>
> >>> @@ -101,48 +123,152 @@ EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
> >>>    */
> >>>   void pci_epc_mem_exit(struct pci_epc *epc)
> >>>   {
> >>> -     struct pci_epc_mem *mem = epc->mem;
> >>> +     struct pci_epc_mem *mem;
> >>> +     int i;
> >>> +
> >>> +     if (!epc->mem_windows)
> >>> +             return;
> >>> +
> >>> +     for (i = 0; i <= epc->mem_windows; i--) {
> >>> +             mem = epc->mem[i];
> >>> +             kfree(mem->bitmap);
> >>> +             kfree(epc->mem[i]);
> >>> +     }
> >>> +     kfree(epc->mem);
> >>>
> >>>       epc->mem = NULL;
> >>> -     kfree(mem->bitmap);
> >>> -     kfree(mem);
> >>> +     epc->mem_windows = 0;
> >>>   }
> >>>   EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
> >>>
> >>> +static int pci_epc_find_best_fit_window(struct pci_epc *epc, size_t size,
> >>> +                                     u32 flags)
> >>> +{
> >>> +     size_t window_least_size = 0;
> >>> +     int best_fit_window = -1;
> >>> +     struct pci_epc_mem *mem;
> >>> +     size_t actual_size;
> >>> +     size_t avail_size;
> >>> +     u32 win_flags;
> >>> +     int i;
> >>> +
> >>> +     for (i = 0; i < epc->mem_windows; i++) {
> >>> +             mem = epc->mem[i];
> >>> +             win_flags = mem->window.flags;
> >>> +
> >>> +             actual_size = ALIGN(size, mem->page_size);
> >>> +             avail_size = mem->window.size - mem->window.map_size;
> >>> +
> >>> +             if (win_flags == 0x0) {
> >>> +                     if (best_fit_window == -1) {
> >>> +                             if (actual_size <= avail_size) {
> >>> +                                     best_fit_window = i;
> >>> +                                     window_least_size = mem->window.size;
> >>> +                             }
> >>> +                     } else {
> >>> +                             if (actual_size <= avail_size &&
> >>> +                                 mem->window.size < window_least_size) {
> >>> +                                     best_fit_window = i;
> >>> +                                     window_least_size = mem->window.size;
> >>> +                             }
> >>> +                     }
> >>> +             } else {
> >>> +                     if (mem->window.map_size &&
> >>> +                         (win_flags | PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC))
> >>> +                             continue;
> >>> +
> >>> +                     if (!(win_flags | flags))
> >>> +                             continue;
> >>> +
> >>> +                     if (best_fit_window == -1) {
> >>> +                             if (actual_size <= avail_size) {
> >>> +                                     best_fit_window = i;
> >>> +                                     window_least_size = mem->window.size;
> >>> +                             }
> >>> +                     } else {
> >>> +                             if (actual_size <= avail_size &&
> >>> +                                 mem->window.size < window_least_size) {
> >>> +                                     best_fit_window = i;
> >>> +                                     window_least_size = mem->window.size;
> >>> +                             }
> >>> +                     }
> >>> +             }
> >>> +     }
> >>> +
> >>> +     return best_fit_window;
> >>> +}
> >>> +
> >>>   /**
> >>>    * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
> >>>    * @epc: the EPC device on which memory has to be allocated
> >>>    * @phys_addr: populate the allocated physical address here
> >>> + * @window: populate the window here which will be used to map PCI address
> >>>    * @size: the size of the address space that has to be allocated
> >>> + * @flags: look for window as requested in flags
> >>>    *
> >>>    * Invoke to allocate memory address from the EPC address space. This
> >>>    * is usually done to map the remote RC address into the local system.
> >>>    */
> >>>   void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> >>> -                                  phys_addr_t *phys_addr, size_t size)
> >>> +                                  phys_addr_t *phys_addr,
> >>> +                                  int *window, size_t size, uint32_t flags)
> >>>   {
> >>> +     int best_fit = PCI_EPC_DEFAULT_WINDOW;
> >>> +     void __iomem *virt_addr = NULL;
> >>> +     struct pci_epc_mem *mem;
> >>> +     unsigned int page_shift;
> >>>       int pageno;
> >>> -     void __iomem *virt_addr;
> >>> -     struct pci_epc_mem *mem = epc->mem;
> >>> -     unsigned int page_shift = ilog2(mem->page_size);
> >>>       int order;
> >>>
> >>> +     if (epc->mem_windows <= 0)
> >>> +             return NULL;
> >>> +
> >>> +     if (epc->mem_windows > 1) {
> >>> +             best_fit = pci_epc_find_best_fit_window(epc, size, flags);
> >>> +             if (best_fit < 0)
> >>> +                     return NULL;
> >>> +     }
> >>> +
> >>> +     mem = epc->mem[best_fit];
> >>>       size = ALIGN(size, mem->page_size);
> >>> +     if (size > (mem->window.size - mem->window.map_size))
> >>> +             return NULL;
> >>> +     page_shift = ilog2(mem->page_size);
> >>>       order = pci_epc_mem_get_order(mem, size);
> >>>
> >>>       pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
> >>>       if (pageno < 0)
> >>>               return NULL;
> >>>
> >>> -     *phys_addr = mem->phys_base + (pageno << page_shift);
> >>> +     *phys_addr = mem->window.phys_base + (pageno << page_shift);
> >>>       virt_addr = ioremap(*phys_addr, size);
> >>> -     if (!virt_addr)
> >>> +     if (!virt_addr) {
> >>>               bitmap_release_region(mem->bitmap, pageno, order);
> >>> +     } else {
> >>> +             mem->window.map_size += size;
> >>> +             *window = best_fit;
> >>> +     }
> >>>
> >>>       return virt_addr;
> >>>   }
> >>>   EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
> >>>
> >>> +static int pci_epc_get_matching_window(struct pci_epc *epc,
> >>> +                                    phys_addr_t phys_addr)
> >>> +{
> >>> +     struct pci_epc_mem *mem;
> >>> +     int i;
> >>> +
> >>> +     for (i = 0; i < epc->mem_windows; i++) {
> >>> +             mem = epc->mem[i];
> >>> +
> >>> +             if (mem->window.phys_base == phys_addr)
> >>> +                     return i;
> >>> +     }
> >>> +
> >>> +     return -EINVAL;
> >>> +}
> >>> +
> >>>   /**
> >>>    * pci_epc_mem_free_addr() - free the allocated memory address
> >>>    * @epc: the EPC device on which memory was allocated
> >>> @@ -155,16 +281,26 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
> >>>   void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
> >>>                          void __iomem *virt_addr, size_t size)
> >>>   {
> >>> +     struct pci_epc_mem *mem;
> >>> +     unsigned int page_shift;
> >>> +     int window = 0;
> >>>       int pageno;
> >>> -     struct pci_epc_mem *mem = epc->mem;
> >>> -     unsigned int page_shift = ilog2(mem->page_size);
> >>>       int order;
> >>>
> >>> +     if (epc->mem_windows > 1) {
> >>> +             window = pci_epc_get_matching_window(epc, phys_addr);
> >>> +             if (window < 0)
> >>> +                     return;
> >>> +     }
> >>> +
> >>> +     mem = epc->mem[window];
> >>> +     page_shift = ilog2(mem->page_size);
> >>>       iounmap(virt_addr);
> >>> -     pageno = (phys_addr - mem->phys_base) >> page_shift;
> >>> +     pageno = (phys_addr - mem->window.phys_base) >> page_shift;
> >>>       size = ALIGN(size, mem->page_size);
> >>>       order = pci_epc_mem_get_order(mem, size);
> >>>       bitmap_release_region(mem->bitmap, pageno, order);
> >>> +     mem->window.map_size -= size;
> >>>   }
> >>>   EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
> >>>
> >>> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> >>> index f641bad..bee6f65 100644
> >>> --- a/include/linux/pci-epc.h
> >>> +++ b/include/linux/pci-epc.h
> >>> @@ -48,7 +48,8 @@ struct pci_epc_ops {
> >>>       void    (*clear_bar)(struct pci_epc *epc, u8 func_no,
> >>>                            struct pci_epf_bar *epf_bar);
> >>>       int     (*map_addr)(struct pci_epc *epc, u8 func_no,
> >>> -                         phys_addr_t addr, u64 pci_addr, size_t size);
> >>> +                         phys_addr_t addr, int window,
> >>> +                         u64 pci_addr, size_t size);
> >>>       void    (*unmap_addr)(struct pci_epc *epc, u8 func_no,
> >>>                             phys_addr_t addr);
> >>>       int     (*set_msi)(struct pci_epc *epc, u8 func_no, u8 interrupts);
> >>> @@ -64,17 +65,57 @@ struct pci_epc_ops {
> >>>       struct module *owner;
> >>>   };
> >>>
> >>> +#define PCI_EPC_DEFAULT_WINDOW               0
> >>> +
> >>> +/**
> >>> + * enum pci_epc_window_flags - flags info for pci_epc_mem_window
> >>> + *
> >>> + * This enum defines how the endpoint controller window should be used
> >>> + * for allocations.
> >>> + *
> >>> + * @PCI_EPC_WINDOW_FLAG_MULTI_ALLOC: Indicates multiple chunks of memory can be
> >>> + *                                allocated from same window
> >>> + * @PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC: Indicates only single memory allocation
> >>> + *                                    is possible on the window
> >>
> >> Instead of NON_MULTI_ALLOC, we could simply have different page_size for
> >> different windows. For a platform that doesn't allow multiple alloc,
> >> page size will be equal to the window size.
> >>
> > I would still prefer this flag and not go with page size = window size
> > as we could allocate unnecessary memory
>
> Nor sure I understand you here. If you have
> PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC, wouldn't it mean, you cannot have
> more than 1 allocation in the entire window. Setting page size same as
> window size will also mean the same thing.
> > that might not be used and also the window sizes might be too large.
>
> IMHO We could still have flags to provide a type for a window and
> directing the allocation to a particular window with a type. But
> at-least for the use case that you are trying to solve, it's simpler to
> have page_size = window_size and the allocation algorithm need not change.
>
this will make things simpler, I'll drop all the above flags and OF
code to parse the regions,
and go with just setting page-size = window-size for my use case.

Cheers,
--Prabhakar