On Sun, Oct 04, 2020 at 12:21:37PM -0700, Rob Clark wrote:
> From: Rob Clark <robdclark@xxxxxxxxxxxx>
>
> Before adding another lock, give ring->lock a more descriptive name.
Reviewed-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 4 ++--
> drivers/gpu/drm/msm/adreno/a5xx_preempt.c | 12 ++++++------
> drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 4 ++--
> drivers/gpu/drm/msm/msm_ringbuffer.c | 2 +-
> drivers/gpu/drm/msm/msm_ringbuffer.h | 7 ++++++-
> 5 files changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> index c941c8138f25..543437a2186e 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
> @@ -36,7 +36,7 @@ void a5xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
> OUT_RING(ring, upper_32_bits(shadowptr(a5xx_gpu, ring)));
> }
>
> - spin_lock_irqsave(&ring->lock, flags);
> + spin_lock_irqsave(&ring->preempt_lock, flags);
>
> /* Copy the shadow to the actual register */
> ring->cur = ring->next;
> @@ -44,7 +44,7 @@ void a5xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
> /* Make sure to wrap wptr if we need to */
> wptr = get_wptr(ring);
>
> - spin_unlock_irqrestore(&ring->lock, flags);
> + spin_unlock_irqrestore(&ring->preempt_lock, flags);
>
> /* Make sure everything is posted before making a decision */
> mb();
> diff --git a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
> index 7e04509c4e1f..183de1139eeb 100644
> --- a/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
> +++ b/drivers/gpu/drm/msm/adreno/a5xx_preempt.c
> @@ -45,9 +45,9 @@ static inline void update_wptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> if (!ring)
> return;
>
> - spin_lock_irqsave(&ring->lock, flags);
> + spin_lock_irqsave(&ring->preempt_lock, flags);
> wptr = get_wptr(ring);
> - spin_unlock_irqrestore(&ring->lock, flags);
> + spin_unlock_irqrestore(&ring->preempt_lock, flags);
>
> gpu_write(gpu, REG_A5XX_CP_RB_WPTR, wptr);
> }
> @@ -62,9 +62,9 @@ static struct msm_ringbuffer *get_next_ring(struct msm_gpu *gpu)
> bool empty;
> struct msm_ringbuffer *ring = gpu->rb[i];
>
> - spin_lock_irqsave(&ring->lock, flags);
> + spin_lock_irqsave(&ring->preempt_lock, flags);
> empty = (get_wptr(ring) == ring->memptrs->rptr);
> - spin_unlock_irqrestore(&ring->lock, flags);
> + spin_unlock_irqrestore(&ring->preempt_lock, flags);
>
> if (!empty)
> return ring;
> @@ -132,9 +132,9 @@ void a5xx_preempt_trigger(struct msm_gpu *gpu)
> }
>
> /* Make sure the wptr doesn't update while we're in motion */
> - spin_lock_irqsave(&ring->lock, flags);
> + spin_lock_irqsave(&ring->preempt_lock, flags);
> a5xx_gpu->preempt[ring->id]->wptr = get_wptr(ring);
> - spin_unlock_irqrestore(&ring->lock, flags);
> + spin_unlock_irqrestore(&ring->preempt_lock, flags);
>
> /* Set the address of the incoming preemption record */
> gpu_write64(gpu, REG_A5XX_CP_CONTEXT_SWITCH_RESTORE_ADDR_LO,
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index 8915882e4444..fc85f008d69d 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -65,7 +65,7 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> OUT_RING(ring, upper_32_bits(shadowptr(a6xx_gpu, ring)));
> }
>
> - spin_lock_irqsave(&ring->lock, flags);
> + spin_lock_irqsave(&ring->preempt_lock, flags);
>
> /* Copy the shadow to the actual register */
> ring->cur = ring->next;
> @@ -73,7 +73,7 @@ static void a6xx_flush(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
> /* Make sure to wrap wptr if we need to */
> wptr = get_wptr(ring);
>
> - spin_unlock_irqrestore(&ring->lock, flags);
> + spin_unlock_irqrestore(&ring->preempt_lock, flags);
>
> /* Make sure everything is posted before making a decision */
> mb();
> diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.c b/drivers/gpu/drm/msm/msm_ringbuffer.c
> index 935bf9b1d941..1b6958e908dc 100644
> --- a/drivers/gpu/drm/msm/msm_ringbuffer.c
> +++ b/drivers/gpu/drm/msm/msm_ringbuffer.c
> @@ -46,7 +46,7 @@ struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
> ring->memptrs_iova = memptrs_iova;
>
> INIT_LIST_HEAD(&ring->submits);
> - spin_lock_init(&ring->lock);
> + spin_lock_init(&ring->preempt_lock);
>
> snprintf(name, sizeof(name), "gpu-ring-%d", ring->id);
>
> diff --git a/drivers/gpu/drm/msm/msm_ringbuffer.h b/drivers/gpu/drm/msm/msm_ringbuffer.h
> index 0987d6bf848c..4956d1bc5d0e 100644
> --- a/drivers/gpu/drm/msm/msm_ringbuffer.h
> +++ b/drivers/gpu/drm/msm/msm_ringbuffer.h
> @@ -46,7 +46,12 @@ struct msm_ringbuffer {
> struct msm_rbmemptrs *memptrs;
> uint64_t memptrs_iova;
> struct msm_fence_context *fctx;
> - spinlock_t lock;
> +
> + /*
> + * preempt_lock protects preemption and serializes wptr updates against
> + * preemption. Can be aquired from irq context.
> + */
> + spinlock_t preempt_lock;
> };
>
> struct msm_ringbuffer *msm_ringbuffer_new(struct msm_gpu *gpu, int id,
> --
> 2.26.2
>
--
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