[v3,05/16] gpu: host1x: Use direct DMA with IOMMU API usage

Message ID 20190201132837.12327-6-thierry.reding@gmail.com
State New
Headers show
Series
  • drm/tegra: Fix IOVA space on Tegra186 and later
Related show

Commit Message

Thierry Reding Feb. 1, 2019, 1:28 p.m.
From: Thierry Reding <treding@nvidia.com>

If we use the IOMMU API directly to map buffers into host1x' IOVA space,
we must make sure that the DMA API doesn't already set up a mapping, or
else translation will fail.

The direct DMA API allows us to allocate memory that will not be mapped
through an IOMMU automatically.

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/host1x/cdma.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

Comments

Dmitry Osipenko Feb. 1, 2019, 2:46 p.m. | #1
01.02.2019 16:28, Thierry Reding пишет:
> From: Thierry Reding <treding@nvidia.com>
> 
> If we use the IOMMU API directly to map buffers into host1x' IOVA space,
> we must make sure that the DMA API doesn't already set up a mapping, or
> else translation will fail.
> 
> The direct DMA API allows us to allocate memory that will not be mapped
> through an IOMMU automatically.
> 
> Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
> Signed-off-by: Thierry Reding <treding@nvidia.com>
> ---
>  drivers/gpu/host1x/cdma.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/host1x/cdma.c b/drivers/gpu/host1x/cdma.c
> index e2d106fa3c0b..a96c4dd1e449 100644
> --- a/drivers/gpu/host1x/cdma.c
> +++ b/drivers/gpu/host1x/cdma.c
> @@ -19,6 +19,7 @@
>  
>  #include <asm/cacheflush.h>
>  #include <linux/device.h>
> +#include <linux/dma-direct.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/host1x.h>
>  #include <linux/interrupt.h>
> @@ -70,6 +71,7 @@ static void host1x_pushbuffer_destroy(struct push_buffer *pb)
>   */
>  static int host1x_pushbuffer_init(struct push_buffer *pb)
>  {
> +	unsigned long attrs = DMA_ATTR_WRITE_COMBINE;
>  	struct host1x_cdma *cdma = pb_to_cdma(pb);
>  	struct host1x *host1x = cdma_to_host1x(cdma);
>  	struct iova *alloc;
> @@ -91,8 +93,8 @@ static int host1x_pushbuffer_init(struct push_buffer *pb)
>  
>  		size = iova_align(&host1x->iova, size);
>  
> -		pb->mapped = dma_alloc_wc(host1x->dev, size, &pb->phys,
> -					  GFP_KERNEL);
> +		pb->mapped = dma_direct_alloc(host1x->dev, size, &pb->phys,
> +					      GFP_KERNEL, attrs);
>  		if (!pb->mapped)
>  			return -ENOMEM;
>  
> @@ -127,7 +129,10 @@ static int host1x_pushbuffer_init(struct push_buffer *pb)
>  iommu_free_iova:
>  	__free_iova(&host1x->iova, alloc);
>  iommu_free_mem:
> -	dma_free_wc(host1x->dev, size, pb->mapped, pb->phys);
> +	if (host1x->domain)
> +		dma_direct_free(host1x->dev, size, pb->mapped, pb->phys, attrs);
> +	else
> +		dma_free_wc(host1x->dev, size, pb->mapped, pb->phys);
>  
>  	return err;
>  }
> 

Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>

Patch

diff --git a/drivers/gpu/host1x/cdma.c b/drivers/gpu/host1x/cdma.c
index e2d106fa3c0b..a96c4dd1e449 100644
--- a/drivers/gpu/host1x/cdma.c
+++ b/drivers/gpu/host1x/cdma.c
@@ -19,6 +19,7 @@ 
 
 #include <asm/cacheflush.h>
 #include <linux/device.h>
+#include <linux/dma-direct.h>
 #include <linux/dma-mapping.h>
 #include <linux/host1x.h>
 #include <linux/interrupt.h>
@@ -70,6 +71,7 @@  static void host1x_pushbuffer_destroy(struct push_buffer *pb)
  */
 static int host1x_pushbuffer_init(struct push_buffer *pb)
 {
+	unsigned long attrs = DMA_ATTR_WRITE_COMBINE;
 	struct host1x_cdma *cdma = pb_to_cdma(pb);
 	struct host1x *host1x = cdma_to_host1x(cdma);
 	struct iova *alloc;
@@ -91,8 +93,8 @@  static int host1x_pushbuffer_init(struct push_buffer *pb)
 
 		size = iova_align(&host1x->iova, size);
 
-		pb->mapped = dma_alloc_wc(host1x->dev, size, &pb->phys,
-					  GFP_KERNEL);
+		pb->mapped = dma_direct_alloc(host1x->dev, size, &pb->phys,
+					      GFP_KERNEL, attrs);
 		if (!pb->mapped)
 			return -ENOMEM;
 
@@ -127,7 +129,10 @@  static int host1x_pushbuffer_init(struct push_buffer *pb)
 iommu_free_iova:
 	__free_iova(&host1x->iova, alloc);
 iommu_free_mem:
-	dma_free_wc(host1x->dev, size, pb->mapped, pb->phys);
+	if (host1x->domain)
+		dma_direct_free(host1x->dev, size, pb->mapped, pb->phys, attrs);
+	else
+		dma_free_wc(host1x->dev, size, pb->mapped, pb->phys);
 
 	return err;
 }