diff mbox series

[v7,4/4] PCI: endpoint: Add NTB MSI support

Message ID 20220822155130.2491006-5-Frank.Li@nxp.com
State New
Headers show
Series [v7,1/4] irqchip: allow pass down .pm field at IRQCHIP_PLATFORM_DRIVER_END | expand

Commit Message

Frank Li Aug. 22, 2022, 3:51 p.m. UTC
┌───────┐           ┌──────────┐
                        │       │           │          │
      ┌─────────────┐   │       │           │ PCI Host │
      │ MSI         │◄┐ │       │           │          │
      │ Controller  │ │ │       │ MSI Write │          │
      └─────────────┘ └─┼───────┼───────────┼─BAR0     │
                        │ PCI   │           │ BAR1     │
                        │ EP    │           │ BAR2     │
                        │       │           │ BAR3     │
                        │       │           │ BAR4     │
                        │       ├──────────►│          │
                        └───────┘           └──────────┘

Linux supports endpoint functions. PCI RC write BAR<n> space like write
to memory. The EP side can't know memory changed by the host driver.

PCI Spec has not defined a standard method to do that. Only define MSI(x)
to let EP notified RC status change.

The basic idea is to trigger an IRQ when PCI RC writes to a memory
address. That's what MSI controller provided. EP drivers just need to
request a platform MSI interrupt, struct msi_msg *msg will pass down a
memory address and data. EP driver will map such memory address to one of
PCI BAR<n>.  PCI RC writes to such memory to trigger EP side IRQ.

Add MSI support for pci-epf-vntb. Query if system has an MSI controller.
Set up doorbell address according to struct msi_msg.

So PCI RC can write this doorbell address to trigger EP side's IRQ.

If no MSI controller exists, fall back to software polling.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/pci/endpoint/functions/pci-epf-vntb.c | 148 +++++++++++++++---
 1 file changed, 122 insertions(+), 26 deletions(-)

Comments

kernel test robot Aug. 22, 2022, 9:32 p.m. UTC | #1
Hi Frank,

I love your patch! Yet something to improve:

[auto build test ERROR on jonmason-ntb/ntb-next]
[also build test ERROR on robh/for-next linus/master v6.0-rc2 next-20220822]
[cannot apply to tip/irq/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Frank-Li/PCI-EP-driver-support-MSI-doorbell-from-host/20220822-235323
base:   https://github.com/jonmason/ntb ntb-next
config: microblaze-randconfig-r005-20220821 (https://download.01.org/0day-ci/archive/20220823/202208230543.fAaLXJy7-lkp@intel.com/config)
compiler: microblaze-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/d98704aefa5b57814d7b9b1b40160df34977b2b6
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Frank-Li/PCI-EP-driver-support-MSI-doorbell-from-host/20220822-235323
        git checkout d98704aefa5b57814d7b9b1b40160df34977b2b6
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=microblaze SHELL=/bin/bash drivers/pci/endpoint/functions/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   drivers/pci/endpoint/functions/pci-epf-vntb.c: In function 'epf_ntb_epc_msi_init':
>> drivers/pci/endpoint/functions/pci-epf-vntb.c:786:13: error: implicit declaration of function 'platform_msi_domain_alloc_irqs' [-Werror=implicit-function-declaration]
     786 |         if (platform_msi_domain_alloc_irqs(&ntb->epf->dev,
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/platform_msi_domain_alloc_irqs +786 drivers/pci/endpoint/functions/pci-epf-vntb.c

   771	
   772	static void epf_ntb_epc_msi_init(struct epf_ntb *ntb)
   773	{
   774		struct device *dev = &ntb->epf->dev;
   775		struct irq_domain *domain;
   776		int virq;
   777		int ret;
   778		int i;
   779	
   780		domain = dev_get_msi_domain(ntb->epf->epc->dev.parent);
   781		if (!domain)
   782			return;
   783	
   784		dev_set_msi_domain(dev, domain);
   785	
 > 786		if (platform_msi_domain_alloc_irqs(&ntb->epf->dev,
   787			ntb->db_count,
   788			epf_ntb_write_msi_msg)) {
   789			dev_info(dev, "Can't allocate MSI, fall back to poll mode\n");
   790			return;
   791		}
   792	
   793		dev_info(dev, "vntb use MSI as doorbell\n");
   794	
   795		for (i = 0; i < ntb->db_count; i++) {
   796			virq = msi_get_virq(dev, i);
   797			ret = devm_request_irq(dev, virq,
   798				       epf_ntb_interrupt_handler, 0,
   799				       "ntb", ntb);
   800	
   801			if (ret) {
   802				dev_err(dev, "devm_request_irq() failure, fall back to poll mode\n");
   803				ntb->epf_db_phy = 0;
   804				break;
   805			}
   806	
   807			if (!i)
   808				ntb->msi_virqbase = virq;
   809		}
   810	}
   811
kernel test robot Aug. 23, 2022, 12:45 a.m. UTC | #2
Hi Frank,

I love your patch! Perhaps something to improve:

[auto build test WARNING on jonmason-ntb/ntb-next]
[also build test WARNING on robh/for-next linus/master v6.0-rc2 next-20220822]
[cannot apply to tip/irq/core]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Frank-Li/PCI-EP-driver-support-MSI-doorbell-from-host/20220822-235323
base:   https://github.com/jonmason/ntb ntb-next
config: s390-randconfig-s053-20220821 (https://download.01.org/0day-ci/archive/20220823/202208230844.D25Fw8sg-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 12.1.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-39-gce1a6720-dirty
        # https://github.com/intel-lab-lkp/linux/commit/d98704aefa5b57814d7b9b1b40160df34977b2b6
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Frank-Li/PCI-EP-driver-support-MSI-doorbell-from-host/20220822-235323
        git checkout d98704aefa5b57814d7b9b1b40160df34977b2b6
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=s390 SHELL=/bin/bash drivers/pci/endpoint/functions/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

sparse warnings: (new ones prefixed by >>)
>> drivers/pci/endpoint/functions/pci-epf-vntb.c:567:25: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected void [noderef] __iomem *[assigned] mw_addr @@     got void * @@
   drivers/pci/endpoint/functions/pci-epf-vntb.c:567:25: sparse:     expected void [noderef] __iomem *[assigned] mw_addr
   drivers/pci/endpoint/functions/pci-epf-vntb.c:567:25: sparse:     got void *
   drivers/pci/endpoint/functions/pci-epf-vntb.c:600:41: sparse: sparse: incorrect type in argument 2 (different address spaces) @@     expected void *addr @@     got void [noderef] __iomem *epf_db @@
   drivers/pci/endpoint/functions/pci-epf-vntb.c:600:41: sparse:     expected void *addr
   drivers/pci/endpoint/functions/pci-epf-vntb.c:600:41: sparse:     got void [noderef] __iomem *epf_db
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1201:33: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected void [noderef] __iomem *base @@     got struct epf_ntb_ctrl *reg @@
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1201:33: sparse:     expected void [noderef] __iomem *base
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1201:33: sparse:     got struct epf_ntb_ctrl *reg
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1212:33: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected void [noderef] __iomem *base @@     got struct epf_ntb_ctrl *reg @@
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1212:33: sparse:     expected void [noderef] __iomem *base
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1212:33: sparse:     got struct epf_ntb_ctrl *reg
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1223:33: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected void [noderef] __iomem *base @@     got struct epf_ntb_ctrl *reg @@
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1223:33: sparse:     expected void [noderef] __iomem *base
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1223:33: sparse:     got struct epf_ntb_ctrl *reg
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1235:33: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected void [noderef] __iomem *base @@     got struct epf_ntb_ctrl *reg @@
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1235:33: sparse:     expected void [noderef] __iomem *base
   drivers/pci/endpoint/functions/pci-epf-vntb.c:1235:33: sparse:     got struct epf_ntb_ctrl *reg

vim +567 drivers/pci/endpoint/functions/pci-epf-vntb.c

d98704aefa5b578 Frank Li 2022-08-22  536  
e35f56bb03304ab Frank Li 2022-02-22  537  /**
e35f56bb03304ab Frank Li 2022-02-22  538   * epf_ntb_db_bar_init() - Configure Doorbell window BARs
e35f56bb03304ab Frank Li 2022-02-22  539   * @ntb: NTB device that facilitates communication between HOST and vHOST
e35f56bb03304ab Frank Li 2022-02-22  540   */
e35f56bb03304ab Frank Li 2022-02-22  541  static int epf_ntb_db_bar_init(struct epf_ntb *ntb)
e35f56bb03304ab Frank Li 2022-02-22  542  {
e35f56bb03304ab Frank Li 2022-02-22  543  	const struct pci_epc_features *epc_features;
e35f56bb03304ab Frank Li 2022-02-22  544  	u32 align;
e35f56bb03304ab Frank Li 2022-02-22  545  	struct device *dev = &ntb->epf->dev;
e35f56bb03304ab Frank Li 2022-02-22  546  	int ret;
e35f56bb03304ab Frank Li 2022-02-22  547  	struct pci_epf_bar *epf_bar;
e35f56bb03304ab Frank Li 2022-02-22  548  	void __iomem *mw_addr;
e35f56bb03304ab Frank Li 2022-02-22  549  	enum pci_barno barno;
d98704aefa5b578 Frank Li 2022-08-22  550  	size_t size;
e35f56bb03304ab Frank Li 2022-02-22  551  
e35f56bb03304ab Frank Li 2022-02-22  552  	epc_features = pci_epc_get_features(ntb->epf->epc,
e35f56bb03304ab Frank Li 2022-02-22  553  					    ntb->epf->func_no,
e35f56bb03304ab Frank Li 2022-02-22  554  					    ntb->epf->vfunc_no);
e35f56bb03304ab Frank Li 2022-02-22  555  	align = epc_features->align;
d98704aefa5b578 Frank Li 2022-08-22  556  	size = epf_ntb_db_size(ntb);
e35f56bb03304ab Frank Li 2022-02-22  557  
e35f56bb03304ab Frank Li 2022-02-22  558  	barno = ntb->epf_ntb_bar[BAR_DB];
d98704aefa5b578 Frank Li 2022-08-22  559  	epf_bar = &ntb->epf->bar[barno];
e35f56bb03304ab Frank Li 2022-02-22  560  
d98704aefa5b578 Frank Li 2022-08-22  561  	if (ntb->epf_db_phy) {
d98704aefa5b578 Frank Li 2022-08-22  562  		mw_addr = NULL;
d98704aefa5b578 Frank Li 2022-08-22  563  		epf_bar->phys_addr = ntb->epf_db_phy;
d98704aefa5b578 Frank Li 2022-08-22  564  		epf_bar->barno = barno;
d98704aefa5b578 Frank Li 2022-08-22  565  		epf_bar->size = size;
d98704aefa5b578 Frank Li 2022-08-22  566  	} else {
e35f56bb03304ab Frank Li 2022-02-22 @567  		mw_addr = pci_epf_alloc_space(ntb->epf, size, barno, align, 0);
e35f56bb03304ab Frank Li 2022-02-22  568  		if (!mw_addr) {
e35f56bb03304ab Frank Li 2022-02-22  569  			dev_err(dev, "Failed to allocate OB address\n");
e35f56bb03304ab Frank Li 2022-02-22  570  			return -ENOMEM;
e35f56bb03304ab Frank Li 2022-02-22  571  		}
d98704aefa5b578 Frank Li 2022-08-22  572  	}
e35f56bb03304ab Frank Li 2022-02-22  573  
e35f56bb03304ab Frank Li 2022-02-22  574  	ntb->epf_db = mw_addr;
e35f56bb03304ab Frank Li 2022-02-22  575  
e35f56bb03304ab Frank Li 2022-02-22  576  	ret = pci_epc_set_bar(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no, epf_bar);
e35f56bb03304ab Frank Li 2022-02-22  577  	if (ret) {
e35f56bb03304ab Frank Li 2022-02-22  578  		dev_err(dev, "Doorbell BAR set failed\n");
e35f56bb03304ab Frank Li 2022-02-22  579  			goto err_alloc_peer_mem;
e35f56bb03304ab Frank Li 2022-02-22  580  	}
e35f56bb03304ab Frank Li 2022-02-22  581  	return ret;
e35f56bb03304ab Frank Li 2022-02-22  582  
e35f56bb03304ab Frank Li 2022-02-22  583  err_alloc_peer_mem:
e35f56bb03304ab Frank Li 2022-02-22  584  	pci_epc_mem_free_addr(ntb->epf->epc, epf_bar->phys_addr, mw_addr, epf_bar->size);
e35f56bb03304ab Frank Li 2022-02-22  585  	return -1;
e35f56bb03304ab Frank Li 2022-02-22  586  }
e35f56bb03304ab Frank Li 2022-02-22  587
diff mbox series

Patch

diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
index 1466dd1904175..f6e0b682da000 100644
--- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -44,6 +44,7 @@ 
 #include <linux/pci-epc.h>
 #include <linux/pci-epf.h>
 #include <linux/ntb.h>
+#include <linux/msi.h>
 
 static struct workqueue_struct *kpcintb_workqueue;
 
@@ -143,6 +144,8 @@  struct epf_ntb {
 	void __iomem *vpci_mw_addr[MAX_MW];
 
 	struct delayed_work cmd_handler;
+
+	int msi_virqbase;
 };
 
 #define to_epf_ntb(epf_group) container_of((epf_group), struct epf_ntb, group)
@@ -253,13 +256,15 @@  static void epf_ntb_cmd_handler(struct work_struct *work)
 
 	ntb = container_of(work, struct epf_ntb, cmd_handler.work);
 
-	for (i = 1; i < ntb->db_count; i++) {
-		if (readl(ntb->epf_db + i * 4)) {
-			if (readl(ntb->epf_db + i * 4))
-				ntb->db |= 1 << (i - 1);
+	if (!ntb->epf_db_phy) {
+		for (i = 1; i < ntb->db_count; i++) {
+			if (readl(ntb->epf_db + i * 4)) {
+				if (readl(ntb->epf_db + i * 4))
+					ntb->db |= 1 << (i - 1);
 
-			ntb_db_event(&ntb->ntb, i);
-			writel(0, ntb->epf_db + i * 4);
+				ntb_db_event(&ntb->ntb, i);
+				writel(0, ntb->epf_db + i * 4);
+			}
 		}
 	}
 
@@ -454,11 +459,9 @@  static int epf_ntb_config_spad_bar_alloc(struct epf_ntb *ntb)
 	ctrl->num_mws = ntb->num_mws;
 	ntb->spad_size = spad_size;
 
-	ctrl->db_entry_size = 4;
-
 	for (i = 0; i < ntb->db_count; i++) {
 		ntb->reg->db_data[i] = 1 + i;
-		ntb->reg->db_offset[i] = 0;
+		ntb->reg->db_offset[i] = 4 * i;
 	}
 
 	return 0;
@@ -509,6 +512,28 @@  static int epf_ntb_configure_interrupt(struct epf_ntb *ntb)
 	return 0;
 }
 
+static int epf_ntb_db_size(struct epf_ntb *ntb)
+{
+	const struct pci_epc_features *epc_features;
+	size_t size = 4 * ntb->db_count;
+	u32 align;
+
+	epc_features = pci_epc_get_features(ntb->epf->epc,
+					    ntb->epf->func_no,
+					    ntb->epf->vfunc_no);
+	align = epc_features->align;
+
+	if (size < 128)
+		size = 128;
+
+	if (align)
+		size = ALIGN(size, align);
+	else
+		size = roundup_pow_of_two(size);
+
+	return size;
+}
+
 /**
  * epf_ntb_db_bar_init() - Configure Doorbell window BARs
  * @ntb: NTB device that facilitates communication between HOST and vHOST
@@ -522,33 +547,32 @@  static int epf_ntb_db_bar_init(struct epf_ntb *ntb)
 	struct pci_epf_bar *epf_bar;
 	void __iomem *mw_addr;
 	enum pci_barno barno;
-	size_t size = 4 * ntb->db_count;
+	size_t size;
 
 	epc_features = pci_epc_get_features(ntb->epf->epc,
 					    ntb->epf->func_no,
 					    ntb->epf->vfunc_no);
 	align = epc_features->align;
-
-	if (size < 128)
-		size = 128;
-
-	if (align)
-		size = ALIGN(size, align);
-	else
-		size = roundup_pow_of_two(size);
+	size = epf_ntb_db_size(ntb);
 
 	barno = ntb->epf_ntb_bar[BAR_DB];
+	epf_bar = &ntb->epf->bar[barno];
 
-	mw_addr = pci_epf_alloc_space(ntb->epf, size, barno, align, 0);
-	if (!mw_addr) {
-		dev_err(dev, "Failed to allocate OB address\n");
-		return -ENOMEM;
+	if (ntb->epf_db_phy) {
+		mw_addr = NULL;
+		epf_bar->phys_addr = ntb->epf_db_phy;
+		epf_bar->barno = barno;
+		epf_bar->size = size;
+	} else {
+		mw_addr = pci_epf_alloc_space(ntb->epf, size, barno, align, 0);
+		if (!mw_addr) {
+			dev_err(dev, "Failed to allocate OB address\n");
+			return -ENOMEM;
+		}
 	}
 
 	ntb->epf_db = mw_addr;
 
-	epf_bar = &ntb->epf->bar[barno];
-
 	ret = pci_epc_set_bar(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no, epf_bar);
 	if (ret) {
 		dev_err(dev, "Doorbell BAR set failed\n");
@@ -704,6 +728,77 @@  static int epf_ntb_init_epc_bar(struct epf_ntb *ntb)
 	return 0;
 }
 
+static void epf_ntb_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg)
+{
+	struct epf_ntb *ntb = dev_get_drvdata(desc->dev);
+	struct epf_ntb_ctrl *reg = ntb->reg;
+	int size = epf_ntb_db_size(ntb);
+	u64 addr;
+
+	addr = msg->address_hi;
+	addr <<= 32;
+	addr |= msg->address_lo;
+
+	reg->db_data[desc->msi_index] = msg->data;
+
+	if (desc->msi_index == 0)
+		ntb->epf_db_phy = round_down(addr, size);
+
+	reg->db_offset[desc->msi_index] = addr - ntb->epf_db_phy;
+}
+
+static irqreturn_t epf_ntb_interrupt_handler(int irq, void *data)
+{
+	struct epf_ntb *ntb = data;
+	int index;
+
+	index = irq - ntb->msi_virqbase;
+	ntb->db |= 1 << (index - 1);
+	ntb_db_event(&ntb->ntb, index);
+
+	return IRQ_HANDLED;
+}
+
+static void epf_ntb_epc_msi_init(struct epf_ntb *ntb)
+{
+	struct device *dev = &ntb->epf->dev;
+	struct irq_domain *domain;
+	int virq;
+	int ret;
+	int i;
+
+	domain = dev_get_msi_domain(ntb->epf->epc->dev.parent);
+	if (!domain)
+		return;
+
+	dev_set_msi_domain(dev, domain);
+
+	if (platform_msi_domain_alloc_irqs(&ntb->epf->dev,
+		ntb->db_count,
+		epf_ntb_write_msi_msg)) {
+		dev_info(dev, "Can't allocate MSI, fall back to poll mode\n");
+		return;
+	}
+
+	dev_info(dev, "vntb use MSI as doorbell\n");
+
+	for (i = 0; i < ntb->db_count; i++) {
+		virq = msi_get_virq(dev, i);
+		ret = devm_request_irq(dev, virq,
+			       epf_ntb_interrupt_handler, 0,
+			       "ntb", ntb);
+
+		if (ret) {
+			dev_err(dev, "devm_request_irq() failure, fall back to poll mode\n");
+			ntb->epf_db_phy = 0;
+			break;
+		}
+
+		if (!i)
+			ntb->msi_virqbase = virq;
+	}
+}
+
 /**
  * epf_ntb_epc_init() - Initialize NTB interface
  * @ntb: NTB device that facilitates communication between HOST and vHOST2
@@ -1299,14 +1394,15 @@  static int epf_ntb_bind(struct pci_epf *epf)
 		goto err_bar_alloc;
 	}
 
+	epf_set_drvdata(epf, ntb);
+	epf_ntb_epc_msi_init(ntb);
+
 	ret = epf_ntb_epc_init(ntb);
 	if (ret) {
 		dev_err(dev, "Failed to initialize EPC\n");
 		goto err_bar_alloc;
 	}
 
-	epf_set_drvdata(epf, ntb);
-
 	pci_space[0] = (ntb->vntb_pid << 16) | ntb->vntb_vid;
 	pci_vntb_table[0].vendor = ntb->vntb_vid;
 	pci_vntb_table[0].device = ntb->vntb_pid;