Re: [PATCH v2 01/18] arm: dma-mapping: arm_iommu_attach_device: automatically set max_seg_size

2014-09-25 Thread Marek Szyprowski 

Hello,

On 2014-09-24 19:06, Will Deacon wrote:

Hi Marek,

On Tue, Sep 16, 2014 at 12:54:28PM +0100, Marek Szyprowski wrote:

If device has no max_seg_size set, we assume that there is no limit and
force it to DMA_BIT_MASK(32) to always use contiguous mappings in DMA
address space.

Signed-off-by: Marek Szyprowski m.szyprow...@samsung.com
---
  arch/arm/mm/dma-mapping.c | 16 
  1 file changed, 16 insertions(+)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index bcd5f836f27e..84705e24571b 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -2050,6 +2050,22 @@ int arm_iommu_attach_device(struct device *dev,
  {
int err;
  
+	/*

+* if device has no max_seg_size set, we assume that there is no limit
+* and force it to DMA_BIT_MASK(32) to always use contiguous mappings
+* in DMA address space
+*/
+   if (!dev-dma_parms) {
+   dev-dma_parms = kzalloc(sizeof(*dev-dma_parms), GFP_KERNEL);
+   if (!dev-dma_parms)
+   return -ENOMEM;
+   }
+   if (!dev-dma_parms-max_segment_size) {
+   err = dma_set_max_seg_size(dev, DMA_BIT_MASK(32));

Would it make more sense to base this default value off the dma_mask?
In my IOMMU series, of_dma_configure passes back a size parameter to
arch_setup_dma_ops which is calculated from the dma-ranges property or the
coherent dma mask if the ranges property is absent, so maybe we should set
this there too?


Right, good idea. This patch predates your arch_setup_dma_ops changes, so I
had to use something. The value taken from dma_mask is much better than 
hardcoded
DMA_BIT_MASK(32). Do you want to include an updated patch in next 
version of your

arch_setup_dma_ops patchset?

Best regards
--
Marek Szyprowski, PhD
Samsung RD Institute Poland

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Re: [PATCH v2 01/18] arm: dma-mapping: arm_iommu_attach_device: automatically set max_seg_size

2014-09-25 Thread Will Deacon 
On Thu, Sep 25, 2014 at 11:43:35AM +0100, Marek Szyprowski wrote:
 On 2014-09-24 19:06, Will Deacon wrote:
  On Tue, Sep 16, 2014 at 12:54:28PM +0100, Marek Szyprowski wrote:
  If device has no max_seg_size set, we assume that there is no limit and
  force it to DMA_BIT_MASK(32) to always use contiguous mappings in DMA
  address space.
 
  Signed-off-by: Marek Szyprowski m.szyprow...@samsung.com
  ---
arch/arm/mm/dma-mapping.c | 16 
1 file changed, 16 insertions(+)
 
  diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
  index bcd5f836f27e..84705e24571b 100644
  --- a/arch/arm/mm/dma-mapping.c
  +++ b/arch/arm/mm/dma-mapping.c
  @@ -2050,6 +2050,22 @@ int arm_iommu_attach_device(struct device *dev,
{
 int err;

  +  /*
  +   * if device has no max_seg_size set, we assume that there is no limit
  +   * and force it to DMA_BIT_MASK(32) to always use contiguous mappings
  +   * in DMA address space
  +   */
  +  if (!dev-dma_parms) {
  +  dev-dma_parms = kzalloc(sizeof(*dev-dma_parms), GFP_KERNEL);
  +  if (!dev-dma_parms)
  +  return -ENOMEM;
  +  }
  +  if (!dev-dma_parms-max_segment_size) {
  +  err = dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
  Would it make more sense to base this default value off the dma_mask?
  In my IOMMU series, of_dma_configure passes back a size parameter to
  arch_setup_dma_ops which is calculated from the dma-ranges property or the
  coherent dma mask if the ranges property is absent, so maybe we should set
  this there too?
 
 Right, good idea. This patch predates your arch_setup_dma_ops changes, so I
 had to use something. The value taken from dma_mask is much better than 
 hardcoded
 DMA_BIT_MASK(32). Do you want to include an updated patch in next 
 version of your
 arch_setup_dma_ops patchset?

Sure, I'll have a go at rolling that in.

Cheers,

Will
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Re: [PATCH v2 01/18] arm: dma-mapping: arm_iommu_attach_device: automatically set max_seg_size

2014-09-24 Thread Will Deacon 
Hi Marek,

On Tue, Sep 16, 2014 at 12:54:28PM +0100, Marek Szyprowski wrote:
 If device has no max_seg_size set, we assume that there is no limit and
 force it to DMA_BIT_MASK(32) to always use contiguous mappings in DMA
 address space.
 
 Signed-off-by: Marek Szyprowski m.szyprow...@samsung.com
 ---
  arch/arm/mm/dma-mapping.c | 16 
  1 file changed, 16 insertions(+)
 
 diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
 index bcd5f836f27e..84705e24571b 100644
 --- a/arch/arm/mm/dma-mapping.c
 +++ b/arch/arm/mm/dma-mapping.c
 @@ -2050,6 +2050,22 @@ int arm_iommu_attach_device(struct device *dev,
  {
   int err;
  
 + /*
 +  * if device has no max_seg_size set, we assume that there is no limit
 +  * and force it to DMA_BIT_MASK(32) to always use contiguous mappings
 +  * in DMA address space
 +  */
 + if (!dev-dma_parms) {
 + dev-dma_parms = kzalloc(sizeof(*dev-dma_parms), GFP_KERNEL);
 + if (!dev-dma_parms)
 + return -ENOMEM;
 + }
 + if (!dev-dma_parms-max_segment_size) {
 + err = dma_set_max_seg_size(dev, DMA_BIT_MASK(32));

Would it make more sense to base this default value off the dma_mask?
In my IOMMU series, of_dma_configure passes back a size parameter to
arch_setup_dma_ops which is calculated from the dma-ranges property or the
coherent dma mask if the ranges property is absent, so maybe we should set
this there too?

Will
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[PATCH v2 01/18] arm: dma-mapping: arm_iommu_attach_device: automatically set max_seg_size

2014-09-16 Thread Marek Szyprowski 
If device has no max_seg_size set, we assume that there is no limit and
force it to DMA_BIT_MASK(32) to always use contiguous mappings in DMA
address space.

Signed-off-by: Marek Szyprowski m.szyprow...@samsung.com
---
 arch/arm/mm/dma-mapping.c | 16 
 1 file changed, 16 insertions(+)

diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index bcd5f836f27e..84705e24571b 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -2050,6 +2050,22 @@ int arm_iommu_attach_device(struct device *dev,
 {
int err;
 
+   /*
+* if device has no max_seg_size set, we assume that there is no limit
+* and force it to DMA_BIT_MASK(32) to always use contiguous mappings
+* in DMA address space
+*/
+   if (!dev-dma_parms) {
+   dev-dma_parms = kzalloc(sizeof(*dev-dma_parms), GFP_KERNEL);
+   if (!dev-dma_parms)
+   return -ENOMEM;
+   }
+   if (!dev-dma_parms-max_segment_size) {
+   err = dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
+   if (err)
+   return err;
+   }
+
err = iommu_attach_device(mapping-domain, dev);
if (err)
return err;
-- 
1.9.2

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