[PATCH 1/2] drm/msm: gpu: don't abuse dma_alloc for non-DMA allocations

[PATCH 1/2] drm/msm: gpu: don't abuse dma_alloc for non-DMA allocations

[Arnd Bergmann]

In zap_shader_load_mdt(), we pass a pointer to a phys_addr_t
into dmam_alloc_coherent, which the compiler warns about:

drivers/gpu/drm/msm/adreno/a5xx_gpu.c: In function 'zap_shader_load_mdt':
drivers/gpu/drm/msm/adreno/a5xx_gpu.c:54:50: error: passing argument 3 of 'dmam_alloc_coherent' from incompatible pointer type [-Werror=incompatible-pointer-types]

The returned DMA address is later passed on to a function that
takes a phys_addr_t, so it's clearly wrong to use the DMA
mapping interface here: the memory may be uncached, or the
address may be completely wrong if there is an IOMMU connected
to the device.

My interpretation is that using dmam_alloc_coherent() had two
purposes:

 a) get a chunk of consecutive memory that may be larger than
    the limit for kmalloc()

 b) use the devres infrastructure to simplify the unwinding
    in the error case.

I think ideally we'd use a devres-based version of
alloc_pages_exact() here, but since that doesn't exist,
let's use devm_get_free_pages() instead. This wastes a little
memory as the size gets rounded up to a power of two, but
is otherwise harmless. If we want to save memory here, calling
devm_free_pages() to release the memory once it is no longer
needed is probably better anyway.

Fixes: 7c65817e6d38 ("drm/msm: gpu: Enable zap shader for A5XX")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
index b4b54f1c24bc..eee9ac81aaa1 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -51,11 +51,13 @@ static int zap_shader_load_mdt(struct device *dev, const char *fwname)
 	}
 
 	/* Allocate memory for the firmware image */
-	mem_region = dmam_alloc_coherent(dev, mem_size, &mem_phys, GFP_KERNEL);
+	mem_region = (void *)devm_get_free_pages(dev, GFP_KERNEL,
+			get_order(mem_size));
 	if (!mem_region) {
 		ret = -ENOMEM;
 		goto out;
 	}
+	mem_phys = virt_to_phys(mem_region);
 
 	/* Load the rest of the MDT */
 	ret = qcom_mdt_load(dev, fw, fwname, GPU_PAS_ID, mem_region, mem_phys,
-- 
2.9.0

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[PATCH 2/2] drm/msm: gpu: call qcom_mdt interfaces only for ARCH_QCOM

[Arnd Bergmann]

When compile-testing for something other than ARCH_QCOM,
we run into a link error:

drivers/gpu/drm/msm/adreno/a5xx_gpu.o: In function `a5xx_hw_init':
a5xx_gpu.c:(.text.a5xx_hw_init+0x600): undefined reference to `qcom_mdt_get_size'
a5xx_gpu.c:(.text.a5xx_hw_init+0x93c): undefined reference to `qcom_mdt_load'

There is already an #ifdef that tries to check for CONFIG_QCOM_MDT_LOADER,
but that symbol is only meaningful when building for ARCH_QCOM.

This adds a compile-time check for ARCH_QCOM, and clarifies the
Kconfig select statement so we don't even try it for other targets.

The check for CONFIG_QCOM_MDT_LOADER can then go away, which also
improves compile-time coverage and makes the code a little nicer
to read.

Fixes: 7c65817e6d38 ("drm/msm: gpu: Enable zap shader for A5XX")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/msm/Kconfig           |  2 +-
 drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 11 +++--------
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
index b638d192ce5e..99d39b2aefa6 100644
--- a/drivers/gpu/drm/msm/Kconfig
+++ b/drivers/gpu/drm/msm/Kconfig
@@ -5,7 +5,7 @@ config DRM_MSM
 	depends on ARCH_QCOM || (ARM && COMPILE_TEST)
 	depends on OF && COMMON_CLK
 	depends on MMU
-	select QCOM_MDT_LOADER
+	select QCOM_MDT_LOADER if ARCH_QCOM
 	select REGULATOR
 	select DRM_KMS_HELPER
 	select DRM_PANEL
diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
index eee9ac81aaa1..b719a5b5b88a 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -26,8 +26,6 @@ static void a5xx_dump(struct msm_gpu *gpu);
 
 #define GPU_PAS_ID 13
 
-#if IS_ENABLED(CONFIG_QCOM_MDT_LOADER)
-
 static int zap_shader_load_mdt(struct device *dev, const char *fwname)
 {
 	const struct firmware *fw;
@@ -36,6 +34,9 @@ static int zap_shader_load_mdt(struct device *dev, const char *fwname)
 	void *mem_region = NULL;
 	int ret;
 
+	if (!IS_ENABLED(CONFIG_ARCH_QCOM))
+		return -EINVAL;
+
 	/* Request the MDT file for the firmware */
 	ret = request_firmware(&fw, fwname, dev);
 	if (ret) {
@@ -75,12 +76,6 @@ static int zap_shader_load_mdt(struct device *dev, const char *fwname)
 
 	return ret;
 }
-#else
-static int zap_shader_load_mdt(struct device *dev, const char *fwname)
-{
-	return -ENODEV;
-}
-#endif
 
 static void a5xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit,
 	struct msm_file_private *ctx)
-- 
2.9.0

Re: [PATCH 2/2] drm/msm: gpu: call qcom_mdt interfaces only for ARCH_QCOM

[Jordan Crouse]

On Tue, Jun 20, 2017 at 10:16:51PM +0200, Arnd Bergmann wrote:
> When compile-testing for something other than ARCH_QCOM,
> we run into a link error:
> 
> drivers/gpu/drm/msm/adreno/a5xx_gpu.o: In function `a5xx_hw_init':
> a5xx_gpu.c:(.text.a5xx_hw_init+0x600): undefined reference to `qcom_mdt_get_size'
> a5xx_gpu.c:(.text.a5xx_hw_init+0x93c): undefined reference to `qcom_mdt_load'
> 
> There is already an #ifdef that tries to check for CONFIG_QCOM_MDT_LOADER,
> but that symbol is only meaningful when building for ARCH_QCOM.
> 
> This adds a compile-time check for ARCH_QCOM, and clarifies the
> Kconfig select statement so we don't even try it for other targets.
> 
> The check for CONFIG_QCOM_MDT_LOADER can then go away, which also
> improves compile-time coverage and makes the code a little nicer
> to read.
> 
> Fixes: 7c65817e6d38 ("drm/msm: gpu: Enable zap shader for A5XX")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

(ARM && COMPILE_TEST) really gives the dependency checks a run for their money.

I assume Bjorn is cool with this.

Acked-by: Jordan Crouse <jcrouse@codeaurora.org>

> ---
>  drivers/gpu/drm/msm/Kconfig           |  2 +-
>  drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 11 +++--------
>  2 files changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/Kconfig b/drivers/gpu/drm/msm/Kconfig
> index b638d192ce5e..99d39b2aefa6 100644
> --- a/drivers/gpu/drm/msm/Kconfig
> +++ b/drivers/gpu/drm/msm/Kconfig
> @@ -5,7 +5,7 @@ config DRM_MSM
>  	depends on ARCH_QCOM || (ARM && COMPILE_TEST)
>  	depends on OF && COMMON_CLK
>  	depends on MMU
> -	select QCOM_MDT_LOADER
> +	select QCOM_MDT_LOADER if ARCH_QCOM
>  	select REGULATOR
>  	select DRM_KMS_HELPER
>  	select DRM_PANEL
> diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> index eee9ac81aaa1..b719a5b5b88a 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> @@ -26,8 +26,6 @@ static void a5xx_dump(struct msm_gpu *gpu);
>  
>  #define GPU_PAS_ID 13
>  
> -#if IS_ENABLED(CONFIG_QCOM_MDT_LOADER)
> -
>  static int zap_shader_load_mdt(struct device *dev, const char *fwname)
>  {
>  	const struct firmware *fw;
> @@ -36,6 +34,9 @@ static int zap_shader_load_mdt(struct device *dev, const char *fwname)
>  	void *mem_region = NULL;
>  	int ret;
>  
> +	if (!IS_ENABLED(CONFIG_ARCH_QCOM))
> +		return -EINVAL;
> +
>  	/* Request the MDT file for the firmware */
>  	ret = request_firmware(&fw, fwname, dev);
>  	if (ret) {
> @@ -75,12 +76,6 @@ static int zap_shader_load_mdt(struct device *dev, const char *fwname)
>  
>  	return ret;
>  }
> -#else
> -static int zap_shader_load_mdt(struct device *dev, const char *fwname)
> -{
> -	return -ENODEV;
> -}
> -#endif
>  
>  static void a5xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit,
>  	struct msm_file_private *ctx)
> -- 
> 2.9.0
> 
> --
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Re: [PATCH 2/2] drm/msm: gpu: call qcom_mdt interfaces only for ARCH_QCOM

[Bjorn Andersson]

On Tue 20 Jun 13:16 PDT 2017, Arnd Bergmann wrote:

> When compile-testing for something other than ARCH_QCOM,
> we run into a link error:
> 
> drivers/gpu/drm/msm/adreno/a5xx_gpu.o: In function `a5xx_hw_init':
> a5xx_gpu.c:(.text.a5xx_hw_init+0x600): undefined reference to `qcom_mdt_get_size'
> a5xx_gpu.c:(.text.a5xx_hw_init+0x93c): undefined reference to `qcom_mdt_load'
> 
> There is already an #ifdef that tries to check for CONFIG_QCOM_MDT_LOADER,
> but that symbol is only meaningful when building for ARCH_QCOM.
> 
> This adds a compile-time check for ARCH_QCOM, and clarifies the
> Kconfig select statement so we don't even try it for other targets.
> 
> The check for CONFIG_QCOM_MDT_LOADER can then go away, which also
> improves compile-time coverage and makes the code a little nicer
> to read.

Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn
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Re: [PATCH 1/2] drm/msm: gpu: don't abuse dma_alloc for non-DMA allocations

[Jordan Crouse]

On Tue, Jun 20, 2017 at 10:16:50PM +0200, Arnd Bergmann wrote:
> In zap_shader_load_mdt(), we pass a pointer to a phys_addr_t
> into dmam_alloc_coherent, which the compiler warns about:
> 
> drivers/gpu/drm/msm/adreno/a5xx_gpu.c: In function 'zap_shader_load_mdt':
> drivers/gpu/drm/msm/adreno/a5xx_gpu.c:54:50: error: passing argument 3 of 'dmam_alloc_coherent' from incompatible pointer type [-Werror=incompatible-pointer-types]
> 
> The returned DMA address is later passed on to a function that
> takes a phys_addr_t, so it's clearly wrong to use the DMA
> mapping interface here: the memory may be uncached, or the
> address may be completely wrong if there is an IOMMU connected
> to the device.
> 
> My interpretation is that using dmam_alloc_coherent() had two
> purposes:
> 
>  a) get a chunk of consecutive memory that may be larger than
>     the limit for kmalloc()
> 
>  b) use the devres infrastructure to simplify the unwinding
>     in the error case.
> 
> I think ideally we'd use a devres-based version of
> alloc_pages_exact() here, but since that doesn't exist,
> let's use devm_get_free_pages() instead. This wastes a little
> memory as the size gets rounded up to a power of two, but
> is otherwise harmless. If we want to save memory here, calling
> devm_free_pages() to release the memory once it is no longer
> needed is probably better anyway.
> 
> Fixes: 7c65817e6d38 ("drm/msm: gpu: Enable zap shader for A5XX")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Seems reasonable to me if Bjorn agrees.

Acked-by: Jordan Crouse <jcrouse@codeaurora.org>

> ---
>  drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> index b4b54f1c24bc..eee9ac81aaa1 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> @@ -51,11 +51,13 @@ static int zap_shader_load_mdt(struct device *dev, const char *fwname)
>  	}
>  
>  	/* Allocate memory for the firmware image */
> -	mem_region = dmam_alloc_coherent(dev, mem_size, &mem_phys, GFP_KERNEL);
> +	mem_region = (void *)devm_get_free_pages(dev, GFP_KERNEL,
> +			get_order(mem_size));
>  	if (!mem_region) {
>  		ret = -ENOMEM;
>  		goto out;
>  	}
> +	mem_phys = virt_to_phys(mem_region);
>  
>  	/* Load the rest of the MDT */
>  	ret = qcom_mdt_load(dev, fw, fwname, GPU_PAS_ID, mem_region, mem_phys,
> -- 
> 2.9.0
> 
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Re: [PATCH 1/2] drm/msm: gpu: don't abuse dma_alloc for non-DMA allocations

[Bjorn Andersson]

On Tue 20 Jun 13:16 PDT 2017, Arnd Bergmann wrote:

> In zap_shader_load_mdt(), we pass a pointer to a phys_addr_t
> into dmam_alloc_coherent, which the compiler warns about:
> 
> drivers/gpu/drm/msm/adreno/a5xx_gpu.c: In function 'zap_shader_load_mdt':
> drivers/gpu/drm/msm/adreno/a5xx_gpu.c:54:50: error: passing argument 3 of 'dmam_alloc_coherent' from incompatible pointer type [-Werror=incompatible-pointer-types]
> 
> The returned DMA address is later passed on to a function that
> takes a phys_addr_t, so it's clearly wrong to use the DMA
> mapping interface here: the memory may be uncached, or the
> address may be completely wrong if there is an IOMMU connected
> to the device.
> 
> My interpretation is that using dmam_alloc_coherent() had two
> purposes:
> 
>  a) get a chunk of consecutive memory that may be larger than
>     the limit for kmalloc()
> 
>  b) use the devres infrastructure to simplify the unwinding
>     in the error case.
> 
> I think ideally we'd use a devres-based version of
> alloc_pages_exact() here, but since that doesn't exist,
> let's use devm_get_free_pages() instead. This wastes a little
> memory as the size gets rounded up to a power of two, but
> is otherwise harmless. If we want to save memory here, calling
> devm_free_pages() to release the memory once it is no longer
> needed is probably better anyway.
> 
> Fixes: 7c65817e6d38 ("drm/msm: gpu: Enable zap shader for A5XX")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
>  drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> index b4b54f1c24bc..eee9ac81aaa1 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> @@ -51,11 +51,13 @@ static int zap_shader_load_mdt(struct device *dev, const char *fwname)
>  	}
>  
>  	/* Allocate memory for the firmware image */
> -	mem_region = dmam_alloc_coherent(dev, mem_size, &mem_phys, GFP_KERNEL);
> +	mem_region = (void *)devm_get_free_pages(dev, GFP_KERNEL,
> +			get_order(mem_size));
>  	if (!mem_region) {
>  		ret = -ENOMEM;
>  		goto out;
>  	}
> +	mem_phys = virt_to_phys(mem_region);
>  
>  	/* Load the rest of the MDT */
>  	ret = qcom_mdt_load(dev, fw, fwname, GPU_PAS_ID, mem_region, mem_phys,
> -- 
> 2.9.0
> 
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