[PATCH] drm/amdgpu/jpeg: fix race condition issue for jpeg start

[Leo Liu]

Reviewed-by: Leo Liu <leo.liu at amd.com>

On 2020-06-10 12:36 p.m., James Zhu wrote:
> Fix race condition issue when multiple jpeg starts are called.
>
> Signed-off-by: James Zhu <James.Zhu at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c | 16 ++++++++++++----
>   drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.h |  2 ++
>   2 files changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
> index d31d65e..8996cb4e 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.c
> @@ -37,6 +37,8 @@ static void amdgpu_jpeg_idle_work_handler(struct work_struct *work);
>   int amdgpu_jpeg_sw_init(struct amdgpu_device *adev)
>   {
>   	INIT_DELAYED_WORK(&adev->jpeg.idle_work, amdgpu_jpeg_idle_work_handler);
> +	mutex_init(&adev->jpeg.jpeg_pg_lock);
> +	atomic_set(&adev->jpeg.total_submission_cnt, 0);
>   
>   	return 0;
>   }
> @@ -54,6 +56,8 @@ int amdgpu_jpeg_sw_fini(struct amdgpu_device *adev)
>   		amdgpu_ring_fini(&adev->jpeg.inst[i].ring_dec);
>   	}
>   
> +	mutex_destroy(&adev->jpeg.jpeg_pg_lock);
> +
>   	return 0;
>   }
>   
> @@ -83,7 +87,7 @@ static void amdgpu_jpeg_idle_work_handler(struct work_struct *work)
>   		fences += amdgpu_fence_count_emitted(&adev->jpeg.inst[i].ring_dec);
>   	}
>   
> -	if (fences == 0)
> +	if (!fences && !atomic_read(&adev->jpeg.total_submission_cnt))
>   		amdgpu_device_ip_set_powergating_state(adev, AMD_IP_BLOCK_TYPE_JPEG,
>   						       AMD_PG_STATE_GATE);
>   	else
> @@ -93,15 +97,19 @@ static void amdgpu_jpeg_idle_work_handler(struct work_struct *work)
>   void amdgpu_jpeg_ring_begin_use(struct amdgpu_ring *ring)
>   {
>   	struct amdgpu_device *adev = ring->adev;
> -	bool set_clocks = !cancel_delayed_work_sync(&adev->jpeg.idle_work);
>   
> -	if (set_clocks)
> -		amdgpu_device_ip_set_powergating_state(adev, AMD_IP_BLOCK_TYPE_JPEG,
> +	atomic_inc(&adev->jpeg.total_submission_cnt);
> +	cancel_delayed_work_sync(&adev->jpeg.idle_work);
> +
> +	mutex_lock(&adev->jpeg.jpeg_pg_lock);
> +	amdgpu_device_ip_set_powergating_state(adev, AMD_IP_BLOCK_TYPE_JPEG,
>   						       AMD_PG_STATE_UNGATE);
> +	mutex_unlock(&adev->jpeg.jpeg_pg_lock);
>   }
>   
>   void amdgpu_jpeg_ring_end_use(struct amdgpu_ring *ring)
>   {
> +	atomic_dec(&ring->adev->jpeg.total_submission_cnt);
>   	schedule_delayed_work(&ring->adev->jpeg.idle_work, JPEG_IDLE_TIMEOUT);
>   }
>   
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.h
> index 5131a0a..55fbff2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_jpeg.h
> @@ -46,6 +46,8 @@ struct amdgpu_jpeg {
>   	unsigned harvest_config;
>   	struct delayed_work idle_work;
>   	enum amd_powergating_state cur_state;
> +	struct mutex jpeg_pg_lock;
> +	atomic_t total_submission_cnt;
>   };
>   
>   int amdgpu_jpeg_sw_init(struct amdgpu_device *adev);