[v2,2/2] drivers: remove force dma flag from buses

Message ID 1521615323-4752-2-git-send-email-nipun.gupta@nxp.com
State New
Headers show
Series
  • [v2,1/2] dma-mapping: move dma configuration to bus infrastructure
Related show

Commit Message

Nipun Gupta March 21, 2018, 6:55 a.m.
With each bus implementing its own DMA configuration callback,
there is no need for bus to explicitly have force_dma in its
global structure. This patch modifies of_dma_configure API to
accept an input parameter which specifies if implicit DMA
configuration is required even when it is not described by the
firmware.

Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
---

Changes in v2:
  - This is a new change suggested by Robin and Christoph
    and is added to the series.

 drivers/amba/bus.c            | 3 +--
 drivers/base/dma-mapping.c    | 4 ++--
 drivers/base/platform.c       | 3 +--
 drivers/bcma/main.c           | 2 +-
 drivers/dma/qcom/hidma_mgmt.c | 2 +-
 drivers/gpu/host1x/bus.c      | 5 ++---
 drivers/of/device.c           | 6 ++++--
 drivers/of/of_reserved_mem.c  | 2 +-
 drivers/pci/pci-driver.c      | 3 +--
 include/linux/device.h        | 4 ----
 include/linux/dma-mapping.h   | 2 +-
 include/linux/of_device.h     | 4 +++-
 12 files changed, 18 insertions(+), 22 deletions(-)

Comments

Greg Kroah-Hartman March 21, 2018, 9:35 a.m. | #1
On Wed, Mar 21, 2018 at 12:25:23PM +0530, Nipun Gupta wrote:
> With each bus implementing its own DMA configuration callback,
> there is no need for bus to explicitly have force_dma in its
> global structure. This patch modifies of_dma_configure API to
> accept an input parameter which specifies if implicit DMA
> configuration is required even when it is not described by the
> firmware.

Having to "remember" what that bool variable means on the end of the
function call is a royal pain over time, right?

Why not just create a new function:
	dma_common_configure_force(dma)
that always does this?  Leave "dma_common_configure()" alone, and then
wrap the old code with these two helper functions that call the 'core'
code with the bool set properly?

That way you do not have to "know" what that parameter is, the function
name just documents it automatically, so when you see it in the
bus-specific code, no need to go and have to hunt for anything.  And if
you are reading the dma core code, it's obvious what is happening as the
functions are all right there.

thanks,

greg k-h
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Nipun Gupta March 21, 2018, 4:28 p.m. | #2
> -----Original Message-----
> From: Greg KH [mailto:gregkh@linuxfoundation.org]
> Sent: Wednesday, March 21, 2018 15:05
> To: Nipun Gupta <nipun.gupta@nxp.com>
> Cc: robin.murphy@arm.com; hch@lst.de; linux@armlinux.org.uk;
> m.szyprowski@samsung.com; bhelgaas@google.com; zajec5@gmail.com;
> andy.gross@linaro.org; david.brown@linaro.org; dan.j.williams@intel.com;
> vinod.koul@intel.com; thierry.reding@gmail.com; robh+dt@kernel.org;
> frowand.list@gmail.com; jarkko.sakkinen@linux.intel.com;
> rafael.j.wysocki@intel.com; dmitry.torokhov@gmail.com; johan@kernel.org;
> msuchanek@suse.de; linux-kernel@vger.kernel.org; iommu@lists.linux-
> foundation.org; linux-wireless@vger.kernel.org; linux-arm-
> msm@vger.kernel.org; linux-soc@vger.kernel.org; dmaengine@vger.kernel.org;
> dri-devel@lists.freedesktop.org; linux-tegra@vger.kernel.org;
> devicetree@vger.kernel.org; linux-pci@vger.kernel.org; Bharat Bhushan
> <bharat.bhushan@nxp.com>; Leo Li <leoyang.li@nxp.com>
> Subject: Re: [PATCH v2 2/2] drivers: remove force dma flag from buses
> 
> On Wed, Mar 21, 2018 at 12:25:23PM +0530, Nipun Gupta wrote:
> > With each bus implementing its own DMA configuration callback,
> > there is no need for bus to explicitly have force_dma in its
> > global structure. This patch modifies of_dma_configure API to
> > accept an input parameter which specifies if implicit DMA
> > configuration is required even when it is not described by the
> > firmware.
> 
> Having to "remember" what that bool variable means on the end of the
> function call is a royal pain over time, right?
> 
> Why not just create a new function:
> 	dma_common_configure_force(dma)
> that always does this?  Leave "dma_common_configure()" alone, and then
> wrap the old code with these two helper functions that call the 'core'
> code with the bool set properly?
> 
> That way you do not have to "know" what that parameter is, the function
> name just documents it automatically, so when you see it in the
> bus-specific code, no need to go and have to hunt for anything.  And if
> you are reading the dma core code, it's obvious what is happening as the
> functions are all right there.

How about we do not pass any flag in 'dma_common_configure()', and inside this
API we pass "true" to 'of_dma_configure()'? I am saying this because currently
both the busses (platform and AMBA) which uses 'dma_common_configure()' passes
"true" value. If we create additional 'dma_common_configure_force()', then
'dma_common_configure()' will not be used anytime and will become redundant.

If someday new busses come and they needs to use similar functionality which
'dma_common_configure()' provides, but with passing "false" to 'of_dma_configure()',
then what you suggests of having two separate such API's will be more reasonable
and can be implemented?

Thanks,
Nipun

> 
> thanks,
> 
> greg k-h
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Greg Kroah-Hartman March 21, 2018, 5:49 p.m. | #3
On Wed, Mar 21, 2018 at 04:28:46PM +0000, Nipun Gupta wrote:
> 
> 
> > -----Original Message-----
> > From: Greg KH [mailto:gregkh@linuxfoundation.org]
> > Sent: Wednesday, March 21, 2018 15:05
> > To: Nipun Gupta <nipun.gupta@nxp.com>
> > Cc: robin.murphy@arm.com; hch@lst.de; linux@armlinux.org.uk;
> > m.szyprowski@samsung.com; bhelgaas@google.com; zajec5@gmail.com;
> > andy.gross@linaro.org; david.brown@linaro.org; dan.j.williams@intel.com;
> > vinod.koul@intel.com; thierry.reding@gmail.com; robh+dt@kernel.org;
> > frowand.list@gmail.com; jarkko.sakkinen@linux.intel.com;
> > rafael.j.wysocki@intel.com; dmitry.torokhov@gmail.com; johan@kernel.org;
> > msuchanek@suse.de; linux-kernel@vger.kernel.org; iommu@lists.linux-
> > foundation.org; linux-wireless@vger.kernel.org; linux-arm-
> > msm@vger.kernel.org; linux-soc@vger.kernel.org; dmaengine@vger.kernel.org;
> > dri-devel@lists.freedesktop.org; linux-tegra@vger.kernel.org;
> > devicetree@vger.kernel.org; linux-pci@vger.kernel.org; Bharat Bhushan
> > <bharat.bhushan@nxp.com>; Leo Li <leoyang.li@nxp.com>
> > Subject: Re: [PATCH v2 2/2] drivers: remove force dma flag from buses
> > 
> > On Wed, Mar 21, 2018 at 12:25:23PM +0530, Nipun Gupta wrote:
> > > With each bus implementing its own DMA configuration callback,
> > > there is no need for bus to explicitly have force_dma in its
> > > global structure. This patch modifies of_dma_configure API to
> > > accept an input parameter which specifies if implicit DMA
> > > configuration is required even when it is not described by the
> > > firmware.
> > 
> > Having to "remember" what that bool variable means on the end of the
> > function call is a royal pain over time, right?
> > 
> > Why not just create a new function:
> > 	dma_common_configure_force(dma)
> > that always does this?  Leave "dma_common_configure()" alone, and then
> > wrap the old code with these two helper functions that call the 'core'
> > code with the bool set properly?
> > 
> > That way you do not have to "know" what that parameter is, the function
> > name just documents it automatically, so when you see it in the
> > bus-specific code, no need to go and have to hunt for anything.  And if
> > you are reading the dma core code, it's obvious what is happening as the
> > functions are all right there.
> 
> How about we do not pass any flag in 'dma_common_configure()', and inside this
> API we pass "true" to 'of_dma_configure()'? I am saying this because currently
> both the busses (platform and AMBA) which uses 'dma_common_configure()' passes
> "true" value. If we create additional 'dma_common_configure_force()', then
> 'dma_common_configure()' will not be used anytime and will become redundant.
> 
> If someday new busses come and they needs to use similar functionality which
> 'dma_common_configure()' provides, but with passing "false" to 'of_dma_configure()',
> then what you suggests of having two separate such API's will be more reasonable
> and can be implemented?

If that makes things "simple", yes, sounds good.

greg k-h
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Christoph Hellwig March 22, 2018, 8:19 a.m. | #4
> --- a/drivers/dma/qcom/hidma_mgmt.c
> +++ b/drivers/dma/qcom/hidma_mgmt.c
> @@ -398,7 +398,7 @@ static int __init hidma_mgmt_of_populate_channels(struct device_node *np)
>  		}
>  		of_node_get(child);
>  		new_pdev->dev.of_node = child;
> -		of_dma_configure(&new_pdev->dev, child);
> +		of_dma_configure(&new_pdev->dev, child, true);
>  		/*
>  		 * It is assumed that calling of_msi_configure is safe on
>  		 * platforms with or without MSI support.

Where did we mark this bus as force_dma before?

> diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> index 9a4f4246..895c83e 100644
> --- a/drivers/of/of_reserved_mem.c
> +++ b/drivers/of/of_reserved_mem.c
> @@ -353,7 +353,7 @@ int of_reserved_mem_device_init_by_idx(struct device *dev,
>  		/* ensure that dma_ops is set for virtual devices
>  		 * using reserved memory
>  		 */
> -		of_dma_configure(dev, np);
> +		of_dma_configure(dev, np, true);

Did all the callers of this one really force dma?  I have a hard time
untangling the call stacks unfortunately.

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Nipun Gupta March 22, 2018, 3:13 p.m. | #5
> -----Original Message-----
> From: Christoph Hellwig [mailto:hch@lst.de]
> Sent: Thursday, March 22, 2018 13:49
> To: Nipun Gupta <nipun.gupta@nxp.com>
> 
> > --- a/drivers/dma/qcom/hidma_mgmt.c
> > +++ b/drivers/dma/qcom/hidma_mgmt.c
> > @@ -398,7 +398,7 @@ static int __init
> hidma_mgmt_of_populate_channels(struct device_node *np)
> >  		}
> >  		of_node_get(child);
> >  		new_pdev->dev.of_node = child;
> > -		of_dma_configure(&new_pdev->dev, child);
> > +		of_dma_configure(&new_pdev->dev, child, true);
> >  		/*
> >  		 * It is assumed that calling of_msi_configure is safe on
> >  		 * platforms with or without MSI support.
> 
> Where did we mark this bus as force_dma before?

I thought these devices to be on the platform bus as the device is of type
'struct platform_device', though I am not sure then why 'of_dma_configure()'
is called here. Is this not on platform bus?

> 
> > diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
> > index 9a4f4246..895c83e 100644
> > --- a/drivers/of/of_reserved_mem.c
> > +++ b/drivers/of/of_reserved_mem.c
> > @@ -353,7 +353,7 @@ int of_reserved_mem_device_init_by_idx(struct device
> *dev,
> >  		/* ensure that dma_ops is set for virtual devices
> >  		 * using reserved memory
> >  		 */
> > -		of_dma_configure(dev, np);
> > +		of_dma_configure(dev, np, true);
> 
> Did all the callers of this one really force dma?  I have a hard time
> untangling the call stacks unfortunately.

I see this API being called indirectly from NXP DPAA device driver which
is for platform bus devices. So I marked 'true' out here. There are more places
from where it is being called.

Thanks,
Nipun
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kbuild test robot March 23, 2018, 4:09 p.m. | #6
Hi Nipun,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.16-rc6 next-20180323]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Nipun-Gupta/dma-mapping-move-dma-configuration-to-bus-infrastructure/20180323-232307
config: i386-randconfig-x013-201811 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   drivers/base/dma-mapping.c: In function 'dma_common_configure':
>> drivers/base/dma-mapping.c:344:9: error: too many arguments to function 'of_dma_configure'
      ret = of_dma_configure(dev, dev->of_node, force_dma);
            ^~~~~~~~~~~~~~~~
   In file included from drivers/base/dma-mapping.c:13:0:
   include/linux/of_device.h:110:19: note: declared here
    static inline int of_dma_configure(struct device *dev, struct device_node *np)
                      ^~~~~~~~~~~~~~~~
--
   drivers/pci/pci-driver.c: In function 'pci_dma_configure':
>> drivers/pci/pci-driver.c:1544:9: error: too many arguments to function 'of_dma_configure'
      ret = of_dma_configure(dev, bridge->parent->of_node, true);
            ^~~~~~~~~~~~~~~~
   In file included from drivers/pci/pci-driver.c:21:0:
   include/linux/of_device.h:110:19: note: declared here
    static inline int of_dma_configure(struct device *dev, struct device_node *np)
                      ^~~~~~~~~~~~~~~~

vim +/of_dma_configure +344 drivers/base/dma-mapping.c

   332	
   333	/*
   334	 * Common configuration to enable DMA API use for a device.
   335	 * A bus can use this function in its 'dma_configure' callback, if
   336	 * suitable for the bus.
   337	 */
   338	int dma_common_configure(struct device *dev, bool force_dma)
   339	{
   340		enum dev_dma_attr attr;
   341		int ret = 0;
   342	
   343		if (dev->of_node) {
 > 344			ret = of_dma_configure(dev, dev->of_node, force_dma);
   345		} else if (has_acpi_companion(dev)) {
   346			attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
   347			if (attr != DEV_DMA_NOT_SUPPORTED)
   348				ret = acpi_dma_configure(dev, attr);
   349		}
   350	
   351		return ret;
   352	}
   353	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
kbuild test robot March 23, 2018, 5:41 p.m. | #7
Hi Nipun,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.16-rc6 next-20180323]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Nipun-Gupta/dma-mapping-move-dma-configuration-to-bus-infrastructure/20180323-232307
config: i386-randconfig-x014-201811 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   drivers//bcma/main.c: In function 'bcma_of_fill_device':
>> drivers//bcma/main.c:210:2: error: too many arguments to function 'of_dma_configure'
     of_dma_configure(&core->dev, node, false);
     ^~~~~~~~~~~~~~~~
   In file included from include/linux/of_platform.h:12:0,
                    from drivers//bcma/main.c:17:
   include/linux/of_device.h:110:19: note: declared here
    static inline int of_dma_configure(struct device *dev, struct device_node *np)
                      ^~~~~~~~~~~~~~~~

vim +/of_dma_configure +210 drivers//bcma/main.c

   198	
   199	static void bcma_of_fill_device(struct device *parent,
   200					struct bcma_device *core)
   201	{
   202		struct device_node *node;
   203	
   204		node = bcma_of_find_child_device(parent, core);
   205		if (node)
   206			core->dev.of_node = node;
   207	
   208		core->irq = bcma_of_get_irq(parent, core, 0);
   209	
 > 210		of_dma_configure(&core->dev, node, false);
   211	}
   212	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Patch

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 2fa1e8b..1d58348 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -174,7 +174,7 @@  static int amba_pm_runtime_resume(struct device *dev)
 
 static int amba_dma_configure(struct device *dev)
 {
-	return dma_common_configure(dev);
+	return dma_common_configure(dev, true);
 }
 
 static const struct dev_pm_ops amba_pm = {
@@ -202,7 +202,6 @@  struct bus_type amba_bustype = {
 	.uevent		= amba_uevent,
 	.dma_configure	= amba_dma_configure,
 	.pm		= &amba_pm,
-	.force_dma	= true,
 };
 
 static int __init amba_init(void)
diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index 48f9af0..03f8584 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -335,13 +335,13 @@  void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
  * A bus can use this function in its 'dma_configure' callback, if
  * suitable for the bus.
  */
-int dma_common_configure(struct device *dev)
+int dma_common_configure(struct device *dev, bool force_dma)
 {
 	enum dev_dma_attr attr;
 	int ret = 0;
 
 	if (dev->of_node) {
-		ret = of_dma_configure(dev, dev->of_node);
+		ret = of_dma_configure(dev, dev->of_node, force_dma);
 	} else if (has_acpi_companion(dev)) {
 		attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
 		if (attr != DEV_DMA_NOT_SUPPORTED)
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index d2d5891..154707c 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -1132,7 +1132,7 @@  int platform_pm_restore(struct device *dev)
 
 static int platform_dma_configure(struct device *dev)
 {
-	return dma_common_configure(dev);
+	return dma_common_configure(dev, true);
 }
 
 static const struct dev_pm_ops platform_dev_pm_ops = {
@@ -1148,7 +1148,6 @@  struct bus_type platform_bus_type = {
 	.uevent		= platform_uevent,
 	.dma_configure	= platform_dma_configure,
 	.pm		= &platform_dev_pm_ops,
-	.force_dma	= true,
 };
 EXPORT_SYMBOL_GPL(platform_bus_type);
 
diff --git a/drivers/bcma/main.c b/drivers/bcma/main.c
index e6986c7..fc1f4ac 100644
--- a/drivers/bcma/main.c
+++ b/drivers/bcma/main.c
@@ -207,7 +207,7 @@  static void bcma_of_fill_device(struct device *parent,
 
 	core->irq = bcma_of_get_irq(parent, core, 0);
 
-	of_dma_configure(&core->dev, node);
+	of_dma_configure(&core->dev, node, false);
 }
 
 unsigned int bcma_core_irq(struct bcma_device *core, int num)
diff --git a/drivers/dma/qcom/hidma_mgmt.c b/drivers/dma/qcom/hidma_mgmt.c
index 000c7019..d64edeb 100644
--- a/drivers/dma/qcom/hidma_mgmt.c
+++ b/drivers/dma/qcom/hidma_mgmt.c
@@ -398,7 +398,7 @@  static int __init hidma_mgmt_of_populate_channels(struct device_node *np)
 		}
 		of_node_get(child);
 		new_pdev->dev.of_node = child;
-		of_dma_configure(&new_pdev->dev, child);
+		of_dma_configure(&new_pdev->dev, child, true);
 		/*
 		 * It is assumed that calling of_msi_configure is safe on
 		 * platforms with or without MSI support.
diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
index fa9896d..211eb6b 100644
--- a/drivers/gpu/host1x/bus.c
+++ b/drivers/gpu/host1x/bus.c
@@ -317,7 +317,7 @@  static int host1x_device_match(struct device *dev, struct device_driver *drv)
 static int host1x_dma_configure(struct device *dev)
 {
 	if (dev->of_node)
-		return of_dma_configure(dev, dev->of_node);
+		return of_dma_configure(dev, dev->of_node, true);
 
 	return 0;
 }
@@ -336,7 +336,6 @@  struct bus_type host1x_bus_type = {
 	.match = host1x_device_match,
 	.dma_configure	= host1x_dma_configure,
 	.pm = &host1x_device_pm_ops,
-	.force_dma = true,
 };
 
 static void __host1x_device_del(struct host1x_device *device)
@@ -425,7 +424,7 @@  static int host1x_device_add(struct host1x *host1x,
 	device->dev.bus = &host1x_bus_type;
 	device->dev.parent = host1x->dev;
 
-	of_dma_configure(&device->dev, host1x->dev->of_node);
+	of_dma_configure(&device->dev, host1x->dev->of_node, true);
 
 	err = host1x_device_parse_dt(device, driver);
 	if (err < 0) {
diff --git a/drivers/of/device.c b/drivers/of/device.c
index 064c818..33d8551 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -76,6 +76,8 @@  int of_device_add(struct platform_device *ofdev)
  * of_dma_configure - Setup DMA configuration
  * @dev:	Device to apply DMA configuration
  * @np:		Pointer to OF node having DMA configuration
+ * @force_dma:  Whether device is to be set up by of_dma_configure() even if
+ *		DMA capability is not explicitly described by firmware.
  *
  * Try to get devices's DMA configuration from DT and update it
  * accordingly.
@@ -84,7 +86,7 @@  int of_device_add(struct platform_device *ofdev)
  * can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
  * to fix up DMA configuration.
  */
-int of_dma_configure(struct device *dev, struct device_node *np)
+int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma)
 {
 	u64 dma_addr, paddr, size = 0;
 	int ret;
@@ -100,7 +102,7 @@  int of_dma_configure(struct device *dev, struct device_node *np)
 		 * DMA configuration regardless of whether "dma-ranges" is
 		 * correctly specified or not.
 		 */
-		if (!dev->bus->force_dma)
+		if (!force_dma)
 			return ret == -ENODEV ? 0 : ret;
 
 		dma_addr = offset = 0;
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 9a4f4246..895c83e 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -353,7 +353,7 @@  int of_reserved_mem_device_init_by_idx(struct device *dev,
 		/* ensure that dma_ops is set for virtual devices
 		 * using reserved memory
 		 */
-		of_dma_configure(dev, np);
+		of_dma_configure(dev, np, true);
 
 		dev_info(dev, "assigned reserved memory node %s\n", rmem->name);
 	} else {
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index b473a4c..b15637a 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -1541,7 +1541,7 @@  static int pci_dma_configure(struct device *dev)
 
 	if (IS_ENABLED(CONFIG_OF) && bridge->parent &&
 	    bridge->parent->of_node) {
-		ret = of_dma_configure(dev, bridge->parent->of_node);
+		ret = of_dma_configure(dev, bridge->parent->of_node, true);
 	} else if (has_acpi_companion(bridge)) {
 		attr = acpi_get_dma_attr(to_acpi_device_node(bridge->fwnode));
 		if (attr != DEV_DMA_NOT_SUPPORTED)
@@ -1566,7 +1566,6 @@  struct bus_type pci_bus_type = {
 	.pm		= PCI_PM_OPS_PTR,
 	.num_vf		= pci_bus_num_vf,
 	.dma_configure	= pci_dma_configure,
-	.force_dma	= true,
 };
 EXPORT_SYMBOL(pci_bus_type);
 
diff --git a/include/linux/device.h b/include/linux/device.h
index 1832d90..92c530e 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -98,8 +98,6 @@  extern int __must_check bus_create_file(struct bus_type *,
  * @p:		The private data of the driver core, only the driver core can
  *		touch this.
  * @lock_key:	Lock class key for use by the lock validator
- * @force_dma:	Assume devices on this bus should be set up by dma_configure()
- * 		even if DMA capability is not explicitly described by firmware.
  *
  * A bus is a channel between the processor and one or more devices. For the
  * purposes of the device model, all devices are connected via a bus, even if
@@ -140,8 +138,6 @@  struct bus_type {
 
 	struct subsys_private *p;
 	struct lock_class_key lock_key;
-
-	bool force_dma;
 };
 
 extern int __must_check bus_register(struct bus_type *bus);
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index c15986b..3dba3e6 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -761,7 +761,7 @@  void *dma_mark_declared_memory_occupied(struct device *dev,
 }
 #endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */
 
-int dma_common_configure(struct device *dev);
+int dma_common_configure(struct device *dev, bool force_dma);
 #ifdef CONFIG_HAS_DMA
 int dma_configure(struct device *dev);
 void dma_deconfigure(struct device *dev);
diff --git a/include/linux/of_device.h b/include/linux/of_device.h
index 8da5a1b..b0be3a5 100644
--- a/include/linux/of_device.h
+++ b/include/linux/of_device.h
@@ -55,7 +55,9 @@  static inline struct device_node *of_cpu_device_node_get(int cpu)
 	return of_node_get(cpu_dev->of_node);
 }
 
-int of_dma_configure(struct device *dev, struct device_node *np);
+int of_dma_configure(struct device *dev,
+		     struct device_node *np,
+		     bool force_dma);
 void of_dma_deconfigure(struct device *dev);
 #else /* CONFIG_OF */