[PATCH 0/2] drm/msm/a6xx: LLCC related fix and cleanup

[PATCH 0/2] drm/msm/a6xx: LLCC related fix and cleanup

[Sai Prakash Ranjan]

Patch 1 is a fix to not set the attributes when CONFIG_QCOM_LLCC
is disabled and Patch 2 is a cleanup to create an a6xx specific address
space.

Sai Prakash Ranjan (2):
  drm/msm: Add proper checks for GPU LLCC support
  drm/msm/a6xx: Create an A6XX GPU specific address space

 drivers/gpu/drm/msm/adreno/a6xx_gpu.c   | 48 +++++++++++++++++++++++--
 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 23 +++++-------
 drivers/gpu/drm/msm/adreno/adreno_gpu.h |  7 ++--
 3 files changed, 56 insertions(+), 22 deletions(-)

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH 1/2] drm/msm: Add proper checks for GPU LLCC support

[Sai Prakash Ranjan]

Domain attribute setting for LLCC is guarded by !IS_ERR
check which works fine only when CONFIG_QCOM_LLCC=y but
when it is disabled, the LLCC apis return NULL and that
is not handled by IS_ERR check. Due to this, domain attribute
for LLCC will be set even on GPUs which do not support it
and cause issues, so correct this by using IS_ERR_OR_NULL
checks appropriately. Meanwhile also cleanup comment block
and remove unwanted blank line.

Fixes: 00fd44a1a470 ("drm/msm: Only enable A6xx LLCC code on A6xx")
Fixes: 474dadb8b0d5 ("drm/msm/a6xx: Add support for using system cache(LLC)")
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c   |  2 +-
 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 130661898546..3b798e883f82 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1117,7 +1117,7 @@ static void a6xx_llc_slices_init(struct platform_device *pdev,
 	a6xx_gpu->llc_slice = llcc_slice_getd(LLCC_GPU);
 	a6xx_gpu->htw_llc_slice = llcc_slice_getd(LLCC_GPUHTW);
 
-	if (IS_ERR(a6xx_gpu->llc_slice) && IS_ERR(a6xx_gpu->htw_llc_slice))
+	if (IS_ERR_OR_NULL(a6xx_gpu->llc_slice) && IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice))
 		a6xx_gpu->llc_mmio = ERR_PTR(-EINVAL);
 }
 
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index f09175698827..b35914de1b27 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -200,15 +200,15 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
 	if (!iommu)
 		return NULL;
 
-
 	if (adreno_is_a6xx(adreno_gpu)) {
 		struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
 		struct io_pgtable_domain_attr pgtbl_cfg;
+
 		/*
-		* This allows GPU to set the bus attributes required to use system
-		* cache on behalf of the iommu page table walker.
-		*/
-		if (!IS_ERR(a6xx_gpu->htw_llc_slice)) {
+		 * This allows GPU to set the bus attributes required to use system
+		 * cache on behalf of the iommu page table walker.
+		 */
+		if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice)) {
 			pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
 			iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
 		}
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

[PATCH 2/2] drm/msm/a6xx: Create an A6XX GPU specific address space

[Sai Prakash Ranjan]

A6XX GPUs have support for last level cache(LLC) also known
as system cache and need to set the bus attributes to
use it. Currently we use a generic adreno iommu address space
implementation which are also used by older GPU generations
which do not have LLC and might introduce issues accidentally
and is not clean in a way that anymore additions of GPUs
supporting LLC would have to be guarded under ifdefs. So keep
the generic code separate and make the address space creation
A6XX specific. We also have a helper to set the llc attributes
so that if the newer GPU generations do support them, we can
use it instead of open coding domain attribute setting for each
GPU.

Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
---
 drivers/gpu/drm/msm/adreno/a6xx_gpu.c   | 46 ++++++++++++++++++++++++-
 drivers/gpu/drm/msm/adreno/adreno_gpu.c | 23 +++++--------
 drivers/gpu/drm/msm/adreno/adreno_gpu.h |  7 ++--
 3 files changed, 55 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 3b798e883f82..3c7ad51732bb 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1239,6 +1239,50 @@ static unsigned long a6xx_gpu_busy(struct msm_gpu *gpu)
 	return (unsigned long)busy_time;
 }
 
+static struct msm_gem_address_space *
+a6xx_create_address_space(struct msm_gpu *gpu, struct platform_device *pdev)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
+	struct iommu_domain *iommu;
+	struct msm_mmu *mmu;
+	struct msm_gem_address_space *aspace;
+	u64 start, size;
+
+	iommu = iommu_domain_alloc(&platform_bus_type);
+	if (!iommu)
+		return NULL;
+
+	/*
+	 * This allows GPU to set the bus attributes required to use system
+	 * cache on behalf of the iommu page table walker.
+	 */
+	if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice))
+		adreno_set_llc_attributes(iommu);
+
+	mmu = msm_iommu_new(&pdev->dev, iommu);
+	if (IS_ERR(mmu)) {
+		iommu_domain_free(iommu);
+		return ERR_CAST(mmu);
+	}
+
+	/*
+	 * Use the aperture start or SZ_16M, whichever is greater. This will
+	 * ensure that we align with the allocated pagetable range while still
+	 * allowing room in the lower 32 bits for GMEM and whatnot
+	 */
+	start = max_t(u64, SZ_16M, iommu->geometry.aperture_start);
+	size = iommu->geometry.aperture_end - start + 1;
+
+	aspace = msm_gem_address_space_create(mmu, "gpu",
+		start & GENMASK_ULL(48, 0), size);
+
+	if (IS_ERR(aspace) && !IS_ERR(mmu))
+		mmu->funcs->destroy(mmu);
+
+	return aspace;
+}
+
 static struct msm_gem_address_space *
 a6xx_create_private_address_space(struct msm_gpu *gpu)
 {
@@ -1285,7 +1329,7 @@ static const struct adreno_gpu_funcs funcs = {
 		.gpu_state_get = a6xx_gpu_state_get,
 		.gpu_state_put = a6xx_gpu_state_put,
 #endif
-		.create_address_space = adreno_iommu_create_address_space,
+		.create_address_space = a6xx_create_address_space,
 		.create_private_address_space = a6xx_create_private_address_space,
 		.get_rptr = a6xx_get_rptr,
 	},
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
index b35914de1b27..0f184c3dd9d9 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
@@ -186,11 +186,18 @@ int adreno_zap_shader_load(struct msm_gpu *gpu, u32 pasid)
 	return zap_shader_load_mdt(gpu, adreno_gpu->info->zapfw, pasid);
 }
 
+void adreno_set_llc_attributes(struct iommu_domain *iommu)
+{
+	struct io_pgtable_domain_attr pgtbl_cfg;
+
+	pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
+	iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
+}
+
 struct msm_gem_address_space *
 adreno_iommu_create_address_space(struct msm_gpu *gpu,
 		struct platform_device *pdev)
 {
-	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
 	struct iommu_domain *iommu;
 	struct msm_mmu *mmu;
 	struct msm_gem_address_space *aspace;
@@ -200,20 +207,6 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
 	if (!iommu)
 		return NULL;
 
-	if (adreno_is_a6xx(adreno_gpu)) {
-		struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
-		struct io_pgtable_domain_attr pgtbl_cfg;
-
-		/*
-		 * This allows GPU to set the bus attributes required to use system
-		 * cache on behalf of the iommu page table walker.
-		 */
-		if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice)) {
-			pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
-			iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
-		}
-	}
-
 	mmu = msm_iommu_new(&pdev->dev, iommu);
 	if (IS_ERR(mmu)) {
 		iommu_domain_free(iommu);
diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
index b3d9a333591b..2a3d049b46b5 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
+++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
@@ -212,11 +212,6 @@ static inline int adreno_is_a540(struct adreno_gpu *gpu)
 	return gpu->revn == 540;
 }
 
-static inline bool adreno_is_a6xx(struct adreno_gpu *gpu)
-{
-	return ((gpu->revn < 700 && gpu->revn > 599));
-}
-
 static inline int adreno_is_a618(struct adreno_gpu *gpu)
 {
        return gpu->revn == 618;
@@ -278,6 +273,8 @@ struct msm_gem_address_space *
 adreno_iommu_create_address_space(struct msm_gpu *gpu,
 		struct platform_device *pdev);
 
+void adreno_set_llc_attributes(struct iommu_domain *iommu);
+
 /*
  * For a5xx and a6xx targets load the zap shader that is used to pull the GPU
  * out of secure mode
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH 2/2] drm/msm/a6xx: Create an A6XX GPU specific address space

[AngeloGioacchino Del Regno]

Il 11/01/21 13:04, Sai Prakash Ranjan ha scritto:
> A6XX GPUs have support for last level cache(LLC) also known
> as system cache and need to set the bus attributes to
> use it. Currently we use a generic adreno iommu address space
> implementation which are also used by older GPU generations
> which do not have LLC and might introduce issues accidentally
> and is not clean in a way that anymore additions of GPUs
> supporting LLC would have to be guarded under ifdefs. So keep
> the generic code separate and make the address space creation
> A6XX specific. We also have a helper to set the llc attributes
> so that if the newer GPU generations do support them, we can
> use it instead of open coding domain attribute setting for each
> GPU.
> 

Hello!

> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> ---
>   drivers/gpu/drm/msm/adreno/a6xx_gpu.c   | 46 ++++++++++++++++++++++++-
>   drivers/gpu/drm/msm/adreno/adreno_gpu.c | 23 +++++--------
>   drivers/gpu/drm/msm/adreno/adreno_gpu.h |  7 ++--
>   3 files changed, 55 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index 3b798e883f82..3c7ad51732bb 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -1239,6 +1239,50 @@ static unsigned long a6xx_gpu_busy(struct msm_gpu *gpu)
>   	return (unsigned long)busy_time;
>   }
>   
> +static struct msm_gem_address_space *
> +a6xx_create_address_space(struct msm_gpu *gpu, struct platform_device *pdev)
> +{
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +	struct iommu_domain *iommu;
> +	struct msm_mmu *mmu;
> +	struct msm_gem_address_space *aspace;
> +	u64 start, size;
> +
> +	iommu = iommu_domain_alloc(&platform_bus_type);
> +	if (!iommu)
> +		return NULL;
> +
> +	/*
> +	 * This allows GPU to set the bus attributes required to use system
> +	 * cache on behalf of the iommu page table walker.
> +	 */
> +	if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice))
> +		adreno_set_llc_attributes(iommu);
> +
> +	mmu = msm_iommu_new(&pdev->dev, iommu);
> +	if (IS_ERR(mmu)) {
> +		iommu_domain_free(iommu);
> +		return ERR_CAST(mmu);
> +	}
> +
> +	/*
> +	 * Use the aperture start or SZ_16M, whichever is greater. This will
> +	 * ensure that we align with the allocated pagetable range while still
> +	 * allowing room in the lower 32 bits for GMEM and whatnot
> +	 */
> +	start = max_t(u64, SZ_16M, iommu->geometry.aperture_start);
> +	size = iommu->geometry.aperture_end - start + 1;
> +
> +	aspace = msm_gem_address_space_create(mmu, "gpu",
> +		start & GENMASK_ULL(48, 0), size);
> +
> +	if (IS_ERR(aspace) && !IS_ERR(mmu))
> +		mmu->funcs->destroy(mmu);
> +
> +	return aspace;
> +}
> +

I get what you're trying to do - yes the intentions are good, however...
you are effectively duplicating code 1:1, as this *is* the same as
function adreno_iommu_create_address_space.

I don't see adding two lines to a function as a valid justification to
duplicate all the rest: perhaps, you may want to find another way to do
this;

Here's one of the many ideas, perhaps you could:
1. Introduce a "generic feature" to signal LLCC support (perhaps in
    struct adreno_info ?)
2. If LLCC is supported, and LLCC slices are initialized, set the LLCC
    attributes on the IOMMU. Of course this would mean passing the init
    state of the slices (maybe just a bool would be fine) back to the
    generic adreno_gpu.c

This, unless you tell me that the entire function is going to be a6xx
specific, but that doesn't seem to be the case at all.

Concerns are that when an hypotetical Adreno A7XX comes and perhaps also
uses the LLCC slices, this function will be duplicated yet another time.

>   static struct msm_gem_address_space *
>   a6xx_create_private_address_space(struct msm_gpu *gpu)
>   {
> @@ -1285,7 +1329,7 @@ static const struct adreno_gpu_funcs funcs = {
>   		.gpu_state_get = a6xx_gpu_state_get,
>   		.gpu_state_put = a6xx_gpu_state_put,
>   #endif
> -		.create_address_space = adreno_iommu_create_address_space,
> +		.create_address_space = a6xx_create_address_space,
>   		.create_private_address_space = a6xx_create_private_address_space,
>   		.get_rptr = a6xx_get_rptr,
>   	},
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index b35914de1b27..0f184c3dd9d9 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -186,11 +186,18 @@ int adreno_zap_shader_load(struct msm_gpu *gpu, u32 pasid)
>   	return zap_shader_load_mdt(gpu, adreno_gpu->info->zapfw, pasid);
>   }
>   
> +void adreno_set_llc_attributes(struct iommu_domain *iommu)

Since this function is relative to the iommu part of this driver, I
think that it would be appropriate to give it the same prefix as all
the other functions that are "working in this context".
Hint: adreno_iommu_set_llc_attributes
Alternatively, this two lines function may just be a static inline in
the header....


But then, what are we talking about, here?
Since you should stop code duplication and bring everything back in
here (in a generic way!!!), then this helper would be of no use, at all,
because then you would be just "throwing" these two lines back in the
function adreno_iommu_create_address_space....


> +{
> +	struct io_pgtable_domain_attr pgtbl_cfg;
> +
> +	pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
> +	iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
> +}
> +
>   struct msm_gem_address_space *
>   adreno_iommu_create_address_space(struct msm_gpu *gpu,
>   		struct platform_device *pdev)
>   {
> -	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
>   	struct iommu_domain *iommu;
>   	struct msm_mmu *mmu;
>   	struct msm_gem_address_space *aspace;
> @@ -200,20 +207,6 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
>   	if (!iommu)
>   		return NULL;
>   
> -	if (adreno_is_a6xx(adreno_gpu)) {
> -		struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> -		struct io_pgtable_domain_attr pgtbl_cfg;
> -
> -		/*
> -		 * This allows GPU to set the bus attributes required to use system
> -		 * cache on behalf of the iommu page table walker.
> -		 */
> -		if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice)) {
> -			pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
> -			iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
> -		}
> -	}
> -
>   	mmu = msm_iommu_new(&pdev->dev, iommu);
>   	if (IS_ERR(mmu)) {
>   		iommu_domain_free(iommu);
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> index b3d9a333591b..2a3d049b46b5 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> @@ -212,11 +212,6 @@ static inline int adreno_is_a540(struct adreno_gpu *gpu)
>   	return gpu->revn == 540;
>   }
>   
> -static inline bool adreno_is_a6xx(struct adreno_gpu *gpu)
> -{
> -	return ((gpu->revn < 700 && gpu->revn > 599));
> -}
> -
>   static inline int adreno_is_a618(struct adreno_gpu *gpu)
>   {
>          return gpu->revn == 618;
> @@ -278,6 +273,8 @@ struct msm_gem_address_space *
>   adreno_iommu_create_address_space(struct msm_gpu *gpu,
>   		struct platform_device *pdev);
>   
> +void adreno_set_llc_attributes(struct iommu_domain *iommu);
> +
>   /*
>    * For a5xx and a6xx targets load the zap shader that is used to pull the GPU
>    * out of secure mode
> 

Regards,
- Angelo

Re: [Freedreno] [PATCH 2/2] drm/msm/a6xx: Create an A6XX GPU specific address space

[Rob Clark]

On Mon, Jan 11, 2021 at 4:04 AM Sai Prakash Ranjan
<saiprakash.ranjan@codeaurora.org> wrote:
>
> A6XX GPUs have support for last level cache(LLC) also known
> as system cache and need to set the bus attributes to
> use it. Currently we use a generic adreno iommu address space
> implementation which are also used by older GPU generations
> which do not have LLC and might introduce issues accidentally
> and is not clean in a way that anymore additions of GPUs
> supporting LLC would have to be guarded under ifdefs. So keep
> the generic code separate and make the address space creation
> A6XX specific. We also have a helper to set the llc attributes
> so that if the newer GPU generations do support them, we can
> use it instead of open coding domain attribute setting for each
> GPU.
>
> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> ---
>  drivers/gpu/drm/msm/adreno/a6xx_gpu.c   | 46 ++++++++++++++++++++++++-
>  drivers/gpu/drm/msm/adreno/adreno_gpu.c | 23 +++++--------
>  drivers/gpu/drm/msm/adreno/adreno_gpu.h |  7 ++--
>  3 files changed, 55 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index 3b798e883f82..3c7ad51732bb 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -1239,6 +1239,50 @@ static unsigned long a6xx_gpu_busy(struct msm_gpu *gpu)
>         return (unsigned long)busy_time;
>  }
>
> +static struct msm_gem_address_space *
> +a6xx_create_address_space(struct msm_gpu *gpu, struct platform_device *pdev)
> +{
> +       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +       struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> +       struct iommu_domain *iommu;
> +       struct msm_mmu *mmu;
> +       struct msm_gem_address_space *aspace;
> +       u64 start, size;
> +
> +       iommu = iommu_domain_alloc(&platform_bus_type);
> +       if (!iommu)
> +               return NULL;
> +
> +       /*
> +        * This allows GPU to set the bus attributes required to use system
> +        * cache on behalf of the iommu page table walker.
> +        */
> +       if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice))
> +               adreno_set_llc_attributes(iommu);
> +
> +       mmu = msm_iommu_new(&pdev->dev, iommu);
> +       if (IS_ERR(mmu)) {
> +               iommu_domain_free(iommu);
> +               return ERR_CAST(mmu);
> +       }
> +
> +       /*
> +        * Use the aperture start or SZ_16M, whichever is greater. This will
> +        * ensure that we align with the allocated pagetable range while still
> +        * allowing room in the lower 32 bits for GMEM and whatnot
> +        */
> +       start = max_t(u64, SZ_16M, iommu->geometry.aperture_start);
> +       size = iommu->geometry.aperture_end - start + 1;
> +
> +       aspace = msm_gem_address_space_create(mmu, "gpu",
> +               start & GENMASK_ULL(48, 0), size);
> +
> +       if (IS_ERR(aspace) && !IS_ERR(mmu))
> +               mmu->funcs->destroy(mmu);
> +
> +       return aspace;
> +}
> +
>  static struct msm_gem_address_space *
>  a6xx_create_private_address_space(struct msm_gpu *gpu)
>  {
> @@ -1285,7 +1329,7 @@ static const struct adreno_gpu_funcs funcs = {
>                 .gpu_state_get = a6xx_gpu_state_get,
>                 .gpu_state_put = a6xx_gpu_state_put,
>  #endif
> -               .create_address_space = adreno_iommu_create_address_space,
> +               .create_address_space = a6xx_create_address_space,
>                 .create_private_address_space = a6xx_create_private_address_space,
>                 .get_rptr = a6xx_get_rptr,
>         },
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index b35914de1b27..0f184c3dd9d9 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -186,11 +186,18 @@ int adreno_zap_shader_load(struct msm_gpu *gpu, u32 pasid)
>         return zap_shader_load_mdt(gpu, adreno_gpu->info->zapfw, pasid);
>  }
>
> +void adreno_set_llc_attributes(struct iommu_domain *iommu)
> +{
> +       struct io_pgtable_domain_attr pgtbl_cfg;
> +
> +       pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;

btw, since quirks is the only field in the struct currently, this is
ok.  But better practice to do something like:

        struct io_pgtable_domain_attr pgtbl_cfg = {
                .quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA,
        };

which will zero-initialize any additional fields which might be added
later, rather than inherit random garbage from the stack.

BR,
-R

> +       iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
> +}
> +
>  struct msm_gem_address_space *
>  adreno_iommu_create_address_space(struct msm_gpu *gpu,
>                 struct platform_device *pdev)
>  {
> -       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
>         struct iommu_domain *iommu;
>         struct msm_mmu *mmu;
>         struct msm_gem_address_space *aspace;
> @@ -200,20 +207,6 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
>         if (!iommu)
>                 return NULL;
>
> -       if (adreno_is_a6xx(adreno_gpu)) {
> -               struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> -               struct io_pgtable_domain_attr pgtbl_cfg;
> -
> -               /*
> -                * This allows GPU to set the bus attributes required to use system
> -                * cache on behalf of the iommu page table walker.
> -                */
> -               if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice)) {
> -                       pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
> -                       iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
> -               }
> -       }
> -
>         mmu = msm_iommu_new(&pdev->dev, iommu);
>         if (IS_ERR(mmu)) {
>                 iommu_domain_free(iommu);
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> index b3d9a333591b..2a3d049b46b5 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> @@ -212,11 +212,6 @@ static inline int adreno_is_a540(struct adreno_gpu *gpu)
>         return gpu->revn == 540;
>  }
>
> -static inline bool adreno_is_a6xx(struct adreno_gpu *gpu)
> -{
> -       return ((gpu->revn < 700 && gpu->revn > 599));
> -}
> -
>  static inline int adreno_is_a618(struct adreno_gpu *gpu)
>  {
>         return gpu->revn == 618;
> @@ -278,6 +273,8 @@ struct msm_gem_address_space *
>  adreno_iommu_create_address_space(struct msm_gpu *gpu,
>                 struct platform_device *pdev);
>
> +void adreno_set_llc_attributes(struct iommu_domain *iommu);
> +
>  /*
>   * For a5xx and a6xx targets load the zap shader that is used to pull the GPU
>   * out of secure mode
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>
> _______________________________________________
> Freedreno mailing list
> Freedreno@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/freedreno

Re: [PATCH 2/2] drm/msm/a6xx: Create an A6XX GPU specific address space

[Rob Clark]

On Wed, Jan 20, 2021 at 3:04 AM AngeloGioacchino Del Regno
<angelogioacchino.delregno@somainline.org> wrote:
>
> Il 11/01/21 13:04, Sai Prakash Ranjan ha scritto:
> > A6XX GPUs have support for last level cache(LLC) also known
> > as system cache and need to set the bus attributes to
> > use it. Currently we use a generic adreno iommu address space
> > implementation which are also used by older GPU generations
> > which do not have LLC and might introduce issues accidentally
> > and is not clean in a way that anymore additions of GPUs
> > supporting LLC would have to be guarded under ifdefs. So keep
> > the generic code separate and make the address space creation
> > A6XX specific. We also have a helper to set the llc attributes
> > so that if the newer GPU generations do support them, we can
> > use it instead of open coding domain attribute setting for each
> > GPU.
> >
>
> Hello!
>
> > Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
> > ---
> >   drivers/gpu/drm/msm/adreno/a6xx_gpu.c   | 46 ++++++++++++++++++++++++-
> >   drivers/gpu/drm/msm/adreno/adreno_gpu.c | 23 +++++--------
> >   drivers/gpu/drm/msm/adreno/adreno_gpu.h |  7 ++--
> >   3 files changed, 55 insertions(+), 21 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > index 3b798e883f82..3c7ad51732bb 100644
> > --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> > @@ -1239,6 +1239,50 @@ static unsigned long a6xx_gpu_busy(struct msm_gpu *gpu)
> >       return (unsigned long)busy_time;
> >   }
> >
> > +static struct msm_gem_address_space *
> > +a6xx_create_address_space(struct msm_gpu *gpu, struct platform_device *pdev)
> > +{
> > +     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> > +     struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > +     struct iommu_domain *iommu;
> > +     struct msm_mmu *mmu;
> > +     struct msm_gem_address_space *aspace;
> > +     u64 start, size;
> > +
> > +     iommu = iommu_domain_alloc(&platform_bus_type);
> > +     if (!iommu)
> > +             return NULL;
> > +
> > +     /*
> > +      * This allows GPU to set the bus attributes required to use system
> > +      * cache on behalf of the iommu page table walker.
> > +      */
> > +     if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice))
> > +             adreno_set_llc_attributes(iommu);
> > +
> > +     mmu = msm_iommu_new(&pdev->dev, iommu);
> > +     if (IS_ERR(mmu)) {
> > +             iommu_domain_free(iommu);
> > +             return ERR_CAST(mmu);
> > +     }
> > +
> > +     /*
> > +      * Use the aperture start or SZ_16M, whichever is greater. This will
> > +      * ensure that we align with the allocated pagetable range while still
> > +      * allowing room in the lower 32 bits for GMEM and whatnot
> > +      */
> > +     start = max_t(u64, SZ_16M, iommu->geometry.aperture_start);
> > +     size = iommu->geometry.aperture_end - start + 1;
> > +
> > +     aspace = msm_gem_address_space_create(mmu, "gpu",
> > +             start & GENMASK_ULL(48, 0), size);
> > +
> > +     if (IS_ERR(aspace) && !IS_ERR(mmu))
> > +             mmu->funcs->destroy(mmu);
> > +
> > +     return aspace;
> > +}
> > +
>
> I get what you're trying to do - yes the intentions are good, however...
> you are effectively duplicating code 1:1, as this *is* the same as
> function adreno_iommu_create_address_space.

I had suggested moving this to a6xx, to avoid breaking earlier gens so
much..  (Note a2xx by necessity already has it's own version of
create_address_space().) I would in general tend to favor a small bit
of code duplication to lower the risk of breaking older gens which not
everybody has hw to test.

But I suppose we could add a has_llcc() and move the htw_llc_slice up
to the 'struct adreno_gpu' level.  Casting to a6xx_gpu in common code
isn't a great idea.  Older gens which don't have LLCC (or don't have
LLCC support yet) could leave the slice ptr NULL.

BR,
-R

> I don't see adding two lines to a function as a valid justification to
> duplicate all the rest: perhaps, you may want to find another way to do
> this;
>
> Here's one of the many ideas, perhaps you could:
> 1. Introduce a "generic feature" to signal LLCC support (perhaps in
>     struct adreno_info ?)
> 2. If LLCC is supported, and LLCC slices are initialized, set the LLCC
>     attributes on the IOMMU. Of course this would mean passing the init
>     state of the slices (maybe just a bool would be fine) back to the
>     generic adreno_gpu.c
>
> This, unless you tell me that the entire function is going to be a6xx
> specific, but that doesn't seem to be the case at all.
>
> Concerns are that when an hypotetical Adreno A7XX comes and perhaps also
> uses the LLCC slices, this function will be duplicated yet another time.
>
> >   static struct msm_gem_address_space *
> >   a6xx_create_private_address_space(struct msm_gpu *gpu)
> >   {
> > @@ -1285,7 +1329,7 @@ static const struct adreno_gpu_funcs funcs = {
> >               .gpu_state_get = a6xx_gpu_state_get,
> >               .gpu_state_put = a6xx_gpu_state_put,
> >   #endif
> > -             .create_address_space = adreno_iommu_create_address_space,
> > +             .create_address_space = a6xx_create_address_space,
> >               .create_private_address_space = a6xx_create_private_address_space,
> >               .get_rptr = a6xx_get_rptr,
> >       },
> > diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > index b35914de1b27..0f184c3dd9d9 100644
> > --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > @@ -186,11 +186,18 @@ int adreno_zap_shader_load(struct msm_gpu *gpu, u32 pasid)
> >       return zap_shader_load_mdt(gpu, adreno_gpu->info->zapfw, pasid);
> >   }
> >
> > +void adreno_set_llc_attributes(struct iommu_domain *iommu)
>
> Since this function is relative to the iommu part of this driver, I
> think that it would be appropriate to give it the same prefix as all
> the other functions that are "working in this context".
> Hint: adreno_iommu_set_llc_attributes
> Alternatively, this two lines function may just be a static inline in
> the header....
>
>
> But then, what are we talking about, here?
> Since you should stop code duplication and bring everything back in
> here (in a generic way!!!), then this helper would be of no use, at all,
> because then you would be just "throwing" these two lines back in the
> function adreno_iommu_create_address_space....
>
>
> > +{
> > +     struct io_pgtable_domain_attr pgtbl_cfg;
> > +
> > +     pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
> > +     iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
> > +}
> > +
> >   struct msm_gem_address_space *
> >   adreno_iommu_create_address_space(struct msm_gpu *gpu,
> >               struct platform_device *pdev)
> >   {
> > -     struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> >       struct iommu_domain *iommu;
> >       struct msm_mmu *mmu;
> >       struct msm_gem_address_space *aspace;
> > @@ -200,20 +207,6 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
> >       if (!iommu)
> >               return NULL;
> >
> > -     if (adreno_is_a6xx(adreno_gpu)) {
> > -             struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
> > -             struct io_pgtable_domain_attr pgtbl_cfg;
> > -
> > -             /*
> > -              * This allows GPU to set the bus attributes required to use system
> > -              * cache on behalf of the iommu page table walker.
> > -              */
> > -             if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice)) {
> > -                     pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
> > -                     iommu_domain_set_attr(iommu, DOMAIN_ATTR_IO_PGTABLE_CFG, &pgtbl_cfg);
> > -             }
> > -     }
> > -
> >       mmu = msm_iommu_new(&pdev->dev, iommu);
> >       if (IS_ERR(mmu)) {
> >               iommu_domain_free(iommu);
> > diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> > index b3d9a333591b..2a3d049b46b5 100644
> > --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> > +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> > @@ -212,11 +212,6 @@ static inline int adreno_is_a540(struct adreno_gpu *gpu)
> >       return gpu->revn == 540;
> >   }
> >
> > -static inline bool adreno_is_a6xx(struct adreno_gpu *gpu)
> > -{
> > -     return ((gpu->revn < 700 && gpu->revn > 599));
> > -}
> > -
> >   static inline int adreno_is_a618(struct adreno_gpu *gpu)
> >   {
> >          return gpu->revn == 618;
> > @@ -278,6 +273,8 @@ struct msm_gem_address_space *
> >   adreno_iommu_create_address_space(struct msm_gpu *gpu,
> >               struct platform_device *pdev);
> >
> > +void adreno_set_llc_attributes(struct iommu_domain *iommu);
> > +
> >   /*
> >    * For a5xx and a6xx targets load the zap shader that is used to pull the GPU
> >    * out of secure mode
> >
>
> Regards,
> - Angelo

Re: [Freedreno] [PATCH 2/2] drm/msm/a6xx: Create an A6XX GPU specific address space

[Sai Prakash Ranjan]

On 2021-01-20 21:48, Rob Clark wrote:
> On Mon, Jan 11, 2021 at 4:04 AM Sai Prakash Ranjan
> <saiprakash.ranjan@codeaurora.org> wrote:
>> 
>> A6XX GPUs have support for last level cache(LLC) also known
>> as system cache and need to set the bus attributes to
>> use it. Currently we use a generic adreno iommu address space
>> implementation which are also used by older GPU generations
>> which do not have LLC and might introduce issues accidentally
>> and is not clean in a way that anymore additions of GPUs
>> supporting LLC would have to be guarded under ifdefs. So keep
>> the generic code separate and make the address space creation
>> A6XX specific. We also have a helper to set the llc attributes
>> so that if the newer GPU generations do support them, we can
>> use it instead of open coding domain attribute setting for each
>> GPU.
>> 
>> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>> ---
>>  drivers/gpu/drm/msm/adreno/a6xx_gpu.c   | 46 
>> ++++++++++++++++++++++++-
>>  drivers/gpu/drm/msm/adreno/adreno_gpu.c | 23 +++++--------
>>  drivers/gpu/drm/msm/adreno/adreno_gpu.h |  7 ++--
>>  3 files changed, 55 insertions(+), 21 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c 
>> b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> index 3b798e883f82..3c7ad51732bb 100644
>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> @@ -1239,6 +1239,50 @@ static unsigned long a6xx_gpu_busy(struct 
>> msm_gpu *gpu)
>>         return (unsigned long)busy_time;
>>  }
>> 
>> +static struct msm_gem_address_space *
>> +a6xx_create_address_space(struct msm_gpu *gpu, struct platform_device 
>> *pdev)
>> +{
>> +       struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
>> +       struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
>> +       struct iommu_domain *iommu;
>> +       struct msm_mmu *mmu;
>> +       struct msm_gem_address_space *aspace;
>> +       u64 start, size;
>> +
>> +       iommu = iommu_domain_alloc(&platform_bus_type);
>> +       if (!iommu)
>> +               return NULL;
>> +
>> +       /*
>> +        * This allows GPU to set the bus attributes required to use 
>> system
>> +        * cache on behalf of the iommu page table walker.
>> +        */
>> +       if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice))
>> +               adreno_set_llc_attributes(iommu);
>> +
>> +       mmu = msm_iommu_new(&pdev->dev, iommu);
>> +       if (IS_ERR(mmu)) {
>> +               iommu_domain_free(iommu);
>> +               return ERR_CAST(mmu);
>> +       }
>> +
>> +       /*
>> +        * Use the aperture start or SZ_16M, whichever is greater. 
>> This will
>> +        * ensure that we align with the allocated pagetable range 
>> while still
>> +        * allowing room in the lower 32 bits for GMEM and whatnot
>> +        */
>> +       start = max_t(u64, SZ_16M, iommu->geometry.aperture_start);
>> +       size = iommu->geometry.aperture_end - start + 1;
>> +
>> +       aspace = msm_gem_address_space_create(mmu, "gpu",
>> +               start & GENMASK_ULL(48, 0), size);
>> +
>> +       if (IS_ERR(aspace) && !IS_ERR(mmu))
>> +               mmu->funcs->destroy(mmu);
>> +
>> +       return aspace;
>> +}
>> +
>>  static struct msm_gem_address_space *
>>  a6xx_create_private_address_space(struct msm_gpu *gpu)
>>  {
>> @@ -1285,7 +1329,7 @@ static const struct adreno_gpu_funcs funcs = {
>>                 .gpu_state_get = a6xx_gpu_state_get,
>>                 .gpu_state_put = a6xx_gpu_state_put,
>>  #endif
>> -               .create_address_space = 
>> adreno_iommu_create_address_space,
>> +               .create_address_space = a6xx_create_address_space,
>>                 .create_private_address_space = 
>> a6xx_create_private_address_space,
>>                 .get_rptr = a6xx_get_rptr,
>>         },
>> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c 
>> b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
>> index b35914de1b27..0f184c3dd9d9 100644
>> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
>> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
>> @@ -186,11 +186,18 @@ int adreno_zap_shader_load(struct msm_gpu *gpu, 
>> u32 pasid)
>>         return zap_shader_load_mdt(gpu, adreno_gpu->info->zapfw, 
>> pasid);
>>  }
>> 
>> +void adreno_set_llc_attributes(struct iommu_domain *iommu)
>> +{
>> +       struct io_pgtable_domain_attr pgtbl_cfg;
>> +
>> +       pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA;
> 
> btw, since quirks is the only field in the struct currently, this is
> ok.  But better practice to do something like:
> 
>         struct io_pgtable_domain_attr pgtbl_cfg = {
>                 .quirks = IO_PGTABLE_QUIRK_ARM_OUTER_WBWA,
>         };
> 
> which will zero-initialize any additional fields which might be added
> later, rather than inherit random garbage from the stack.
> 

Right, I will correct this.

Thanks,
Sai

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a 
member
of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH 2/2] drm/msm/a6xx: Create an A6XX GPU specific address space

[Sai Prakash Ranjan]

Hi Angelo,

On 2021-01-20 16:34, AngeloGioacchino Del Regno wrote:
> Il 11/01/21 13:04, Sai Prakash Ranjan ha scritto:
>> A6XX GPUs have support for last level cache(LLC) also known
>> as system cache and need to set the bus attributes to
>> use it. Currently we use a generic adreno iommu address space
>> implementation which are also used by older GPU generations
>> which do not have LLC and might introduce issues accidentally
>> and is not clean in a way that anymore additions of GPUs
>> supporting LLC would have to be guarded under ifdefs. So keep
>> the generic code separate and make the address space creation
>> A6XX specific. We also have a helper to set the llc attributes
>> so that if the newer GPU generations do support them, we can
>> use it instead of open coding domain attribute setting for each
>> GPU.
>> 
> 
> Hello!
> 
>> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>> ---
>>   drivers/gpu/drm/msm/adreno/a6xx_gpu.c   | 46 
>> ++++++++++++++++++++++++-
>>   drivers/gpu/drm/msm/adreno/adreno_gpu.c | 23 +++++--------
>>   drivers/gpu/drm/msm/adreno/adreno_gpu.h |  7 ++--
>>   3 files changed, 55 insertions(+), 21 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c 
>> b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> index 3b798e883f82..3c7ad51732bb 100644
>> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
>> @@ -1239,6 +1239,50 @@ static unsigned long a6xx_gpu_busy(struct 
>> msm_gpu *gpu)
>>   	return (unsigned long)busy_time;
>>   }
>>   +static struct msm_gem_address_space *
>> +a6xx_create_address_space(struct msm_gpu *gpu, struct platform_device 
>> *pdev)
>> +{
>> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
>> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
>> +	struct iommu_domain *iommu;
>> +	struct msm_mmu *mmu;
>> +	struct msm_gem_address_space *aspace;
>> +	u64 start, size;
>> +
>> +	iommu = iommu_domain_alloc(&platform_bus_type);
>> +	if (!iommu)
>> +		return NULL;
>> +
>> +	/*
>> +	 * This allows GPU to set the bus attributes required to use system
>> +	 * cache on behalf of the iommu page table walker.
>> +	 */
>> +	if (!IS_ERR_OR_NULL(a6xx_gpu->htw_llc_slice))
>> +		adreno_set_llc_attributes(iommu);
>> +
>> +	mmu = msm_iommu_new(&pdev->dev, iommu);
>> +	if (IS_ERR(mmu)) {
>> +		iommu_domain_free(iommu);
>> +		return ERR_CAST(mmu);
>> +	}
>> +
>> +	/*
>> +	 * Use the aperture start or SZ_16M, whichever is greater. This will
>> +	 * ensure that we align with the allocated pagetable range while 
>> still
>> +	 * allowing room in the lower 32 bits for GMEM and whatnot
>> +	 */
>> +	start = max_t(u64, SZ_16M, iommu->geometry.aperture_start);
>> +	size = iommu->geometry.aperture_end - start + 1;
>> +
>> +	aspace = msm_gem_address_space_create(mmu, "gpu",
>> +		start & GENMASK_ULL(48, 0), size);
>> +
>> +	if (IS_ERR(aspace) && !IS_ERR(mmu))
>> +		mmu->funcs->destroy(mmu);
>> +
>> +	return aspace;
>> +}
>> +
> 
> I get what you're trying to do - yes the intentions are good, 
> however...
> you are effectively duplicating code 1:1, as this *is* the same as
> function adreno_iommu_create_address_space.
> 
> I don't see adding two lines to a function as a valid justification to
> duplicate all the rest: perhaps, you may want to find another way to do
> this;
> 
> Here's one of the many ideas, perhaps you could:
> 1. Introduce a "generic feature" to signal LLCC support (perhaps in
>    struct adreno_info ?)
> 2. If LLCC is supported, and LLCC slices are initialized, set the LLCC
>    attributes on the IOMMU. Of course this would mean passing the init
>    state of the slices (maybe just a bool would be fine) back to the
>    generic adreno_gpu.c
> 
> This, unless you tell me that the entire function is going to be a6xx
> specific, but that doesn't seem to be the case at all.
> 
> Concerns are that when an hypotetical Adreno A7XX comes and perhaps 
> also
> uses the LLCC slices, this function will be duplicated yet another 
> time.
> 

As Rob mentioned in other reply, this was more of a point to not break
older gen gpus when we add some feature which is specific to a6xx.
So there are a{3,4,5}xx using adreno_iommu_create_address_space and
any addition to a6xx or let's say in future a7xx(assuming we do not
have its own address space impl and use this generic one), then all
these older gens need to be taken care of either via some conditions
and test on those so that they won't break. IMO, rather than keep
adding ifs in the generic code, it is better to have a separate
address space impl.

>>   static struct msm_gem_address_space *
>>   a6xx_create_private_address_space(struct msm_gpu *gpu)
>>   {
>> @@ -1285,7 +1329,7 @@ static const struct adreno_gpu_funcs funcs = {
>>   		.gpu_state_get = a6xx_gpu_state_get,
>>   		.gpu_state_put = a6xx_gpu_state_put,
>>   #endif
>> -		.create_address_space = adreno_iommu_create_address_space,
>> +		.create_address_space = a6xx_create_address_space,
>>   		.create_private_address_space = a6xx_create_private_address_space,
>>   		.get_rptr = a6xx_get_rptr,
>>   	},
>> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c 
>> b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
>> index b35914de1b27..0f184c3dd9d9 100644
>> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
>> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
>> @@ -186,11 +186,18 @@ int adreno_zap_shader_load(struct msm_gpu *gpu, 
>> u32 pasid)
>>   	return zap_shader_load_mdt(gpu, adreno_gpu->info->zapfw, pasid);
>>   }
>>   +void adreno_set_llc_attributes(struct iommu_domain *iommu)
> 
> Since this function is relative to the iommu part of this driver, I
> think that it would be appropriate to give it the same prefix as all
> the other functions that are "working in this context".
> Hint: adreno_iommu_set_llc_attributes

Yes, I will change the name to adreno_iommu_set_llc_attributes.

> Alternatively, this two lines function may just be a static inline in
> the header....
> 
> 
> But then, what are we talking about, here?
> Since you should stop code duplication and bring everything back in
> here (in a generic way!!!), then this helper would be of no use, at 
> all,
> because then you would be just "throwing" these two lines back in the
> function adreno_iommu_create_address_space....
> 
> 

See above reply. Thanks for taking a look.

Thanks,
Sai

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Re: [PATCH 0/2] drm/msm/a6xx: LLCC related fix and cleanup

[patchwork-bot+linux-arm-msm]

Hello:

This series was applied to qcom/linux.git (refs/heads/for-next):

On Mon, 11 Jan 2021 17:34:07 +0530 you wrote:
> Patch 1 is a fix to not set the attributes when CONFIG_QCOM_LLCC
> is disabled and Patch 2 is a cleanup to create an a6xx specific address
> space.
> 
> Sai Prakash Ranjan (2):
>   drm/msm: Add proper checks for GPU LLCC support
>   drm/msm/a6xx: Create an A6XX GPU specific address space
> 
> [...]

Here is the summary with links:
  - [1/2] drm/msm: Add proper checks for GPU LLCC support
    https://git.kernel.org/qcom/c/276619c0923f
  - [2/2] drm/msm/a6xx: Create an A6XX GPU specific address space
    https://git.kernel.org/qcom/c/45596f254061

You are awesome, thank you!
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