Re: [PATCH v4 06/12] drm/amdgpu: create kernel doorbell pages

[Christian König <christian.koenig@xxxxxxx>]

Am 21.06.23 um 14:44 schrieb Shashank Sharma:
> This patch:
> - creates a doorbell page for graphics driver usages.
> - adds a few new varlables in adev->doorbell structure to
>    keep track of kernel's doorbell-bo.
> - removes the adev->doorbell.ptr variable, replaces it with
>    kernel-doorbell-bo's cpu address.
>
> V2: - Create doorbell BO directly, no wrappe functions (Alex)
>      - no additional doorbell structure (Alex, Christian)
>      - Use doorbell_cpu_ptr, remove ioremap (Christian, Alex)
>      - Allocate one extra page of doorbells for MES (Alex)
>
> V4: Move MES doorbell base init into MES related patch (Christian)
>
> Cc: Alex Deucher <alexander.deucher@xxxxxxx>
> Cc: Christian Koenig <christian.koenig@xxxxxxx>
> Signed-off-by: Shashank Sharma <shashank.sharma@xxxxxxx>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h  |  8 ++-
>   .../gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c  | 52 ++++++++++++++-----
>   drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h       |  3 ++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c       |  7 +++
>   4 files changed, 56 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
> index 783e2b8b086c..002899edb9d7 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell.h
> @@ -31,10 +31,15 @@ struct amdgpu_doorbell {
>   	/* doorbell mmio */
>   	resource_size_t		base;
>   	resource_size_t		size;
> -	u32 __iomem		*ptr;
>   
>   	/* Number of doorbells reserved for amdgpu kernel driver */
>   	u32 num_kernel_doorbells;
> +
> +	/* Kernel doorbells */
> +	struct amdgpu_bo *kernel_doorbells;
> +
> +	/* For CPU access of doorbells */
> +	uint32_t *cpu_addr;
>   };
>   
>   /* Reserved doorbells for amdgpu (including multimedia).
> @@ -311,6 +316,7 @@ void amdgpu_mm_wdoorbell64(struct amdgpu_device *adev, u32 index, u64 v);
>    */
>   int amdgpu_doorbell_init(struct amdgpu_device *adev);
>   void amdgpu_doorbell_fini(struct amdgpu_device *adev);
> +int amdgpu_doorbell_create_kernel_doorbells(struct amdgpu_device *adev);
>   
>   #define RDOORBELL32(index) amdgpu_mm_rdoorbell(adev, (index))
>   #define WDOORBELL32(index, v) amdgpu_mm_wdoorbell(adev, (index), (v))
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
> index eb113e38f5e9..dd6744eb5875 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
> @@ -39,7 +39,7 @@ u32 amdgpu_mm_rdoorbell(struct amdgpu_device *adev, u32 index)
>   		return 0;
>   
>   	if (index < adev->doorbell.num_kernel_doorbells)
> -		return readl(adev->doorbell.ptr + index);
> +		return readl(adev->doorbell.cpu_addr + index);
>   
>   	DRM_ERROR("reading beyond doorbell aperture: 0x%08x!\n", index);
>   	return 0;
> @@ -61,7 +61,7 @@ void amdgpu_mm_wdoorbell(struct amdgpu_device *adev, u32 index, u32 v)
>   		return;
>   
>   	if (index < adev->doorbell.num_kernel_doorbells)
> -		writel(v, adev->doorbell.ptr + index);
> +		writel(v, adev->doorbell.cpu_addr + index);
>   	else
>   		DRM_ERROR("writing beyond doorbell aperture: 0x%08x!\n", index);
>   }
> @@ -81,7 +81,7 @@ u64 amdgpu_mm_rdoorbell64(struct amdgpu_device *adev, u32 index)
>   		return 0;
>   
>   	if (index < adev->doorbell.num_kernel_doorbells)
> -		return atomic64_read((atomic64_t *)(adev->doorbell.ptr + index));
> +		return atomic64_read((atomic64_t *)(adev->doorbell.cpu_addr + index));
>   
>   	DRM_ERROR("reading beyond doorbell aperture: 0x%08x!\n", index);
>   	return 0;
> @@ -103,11 +103,43 @@ void amdgpu_mm_wdoorbell64(struct amdgpu_device *adev, u32 index, u64 v)
>   		return;
>   
>   	if (index < adev->doorbell.num_kernel_doorbells)
> -		atomic64_set((atomic64_t *)(adev->doorbell.ptr + index), v);
> +		atomic64_set((atomic64_t *)(adev->doorbell.cpu_addr + index), v);
>   	else
>   		DRM_ERROR("writing beyond doorbell aperture: 0x%08x!\n", index);
>   }
>   
> +/**
> + * amdgpu_doorbell_create_kernel_doorbells - Create kernel doorbells for graphics
> + *
> + * @adev: amdgpu_device pointer
> + *
> + * Creates doorbells for graphics driver usages.
> + * returns 0 on success, error otherwise.
> + */
> +int amdgpu_doorbell_create_kernel_doorbells(struct amdgpu_device *adev)
> +{
> +	int r;
> +	int size;
> +
> +	/* Reserve first num_kernel_doorbells (page-aligned) for kernel ops */
> +	size = ALIGN(adev->doorbell.num_kernel_doorbells * sizeof(u32), PAGE_SIZE);
> +
> +	r = amdgpu_bo_create_kernel(adev,
> +				    size,
> +				    PAGE_SIZE,
> +				    AMDGPU_GEM_DOMAIN_DOORBELL,
> +				    &adev->doorbell.kernel_doorbells,
> +				    NULL,
> +				    (void **)&adev->doorbell.cpu_addr);
> +	if (r) {
> +		DRM_ERROR("Failed to allocate kernel doorbells, err=%d\n", r);
> +		return r;
> +	}
> +
> +	adev->doorbell.num_kernel_doorbells = size / sizeof(u32);
> +	return 0;
> +}
> +
>   /*
>    * GPU doorbell aperture helpers function.
>    */
> @@ -127,7 +159,6 @@ int amdgpu_doorbell_init(struct amdgpu_device *adev)
>   		adev->doorbell.base = 0;
>   		adev->doorbell.size = 0;
>   		adev->doorbell.num_kernel_doorbells = 0;
> -		adev->doorbell.ptr = NULL;
>   		return 0;
>   	}
>   
> @@ -156,12 +187,6 @@ int amdgpu_doorbell_init(struct amdgpu_device *adev)
>   	if (adev->asic_type >= CHIP_VEGA10)
>   		adev->doorbell.num_kernel_doorbells += 0x400;
>   
> -	adev->doorbell.ptr = ioremap(adev->doorbell.base,
> -				     adev->doorbell.num_kernel_doorbells *
> -				     sizeof(u32));
> -	if (adev->doorbell.ptr == NULL)
> -		return -ENOMEM;
> -
>   	return 0;
>   }
>   
> @@ -174,6 +199,7 @@ int amdgpu_doorbell_init(struct amdgpu_device *adev)
>    */
>   void amdgpu_doorbell_fini(struct amdgpu_device *adev)
>   {
> -	iounmap(adev->doorbell.ptr);
> -	adev->doorbell.ptr = NULL;
> +	amdgpu_bo_free_kernel(&adev->doorbell.kernel_doorbells,
> +			      NULL,
> +			      (void **)&adev->doorbell.cpu_addr);
>   }
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h
> index 547ec35691fa..a403418d5eac 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mes.h
> @@ -128,6 +128,9 @@ struct amdgpu_mes {
>   	int                             (*kiq_hw_init)(struct amdgpu_device *adev);
>   	int                             (*kiq_hw_fini)(struct amdgpu_device *adev);
>   
> +	/* MES doorbells */
> +	uint32_t			db_start_dw_offset;
> +

This should probably go into patch #11 as well, apart from that the 
patch is Reviewed-by: Christian König <christian.koenig@xxxxxxx>

Regards,
Christian.

>   	/* ip specific functions */
>   	const struct amdgpu_mes_funcs   *funcs;
>   };
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 6d1587bbda52..c48e97646541 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -1854,6 +1854,13 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
>   		return r;
>   	}
>   
> +	/* Create a boorbell page for kernel usages */
> +	r = amdgpu_doorbell_create_kernel_doorbells(adev);
> +	if (r) {
> +		DRM_ERROR("Failed to initialize kernel doorbells.\n");
> +		return r;
> +	}
> +
>   	/* Initialize preemptible memory pool */
>   	r = amdgpu_preempt_mgr_init(adev);
>   	if (r) {