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authorChristian König <christian.koenig@amd.com>2024-10-08 17:23:22 +0200
committerAlex Deucher <alexander.deucher@amd.com>2024-10-28 16:32:03 -0400
commit57e92d991e31ee237774aa9390586fad83630634 (patch)
treee34e26711f597ddb5f2b2e4160e60fc2aabb729c
parentdac64cb3e029e9ae9ca251798bcb9cdb118d68d5 (diff)
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drm/amdgpu: drop volatile from ring buffer
Volatile only prevents the compiler from re-ordering reads and writes. Since we always only modify the ring buffer from one CPU thread and have an explicit barrier before signaling the HW this should have no effect at all and just prevents compiler optimisations. While at it drop the local variables as well. Signed-off-by: Christian König <christian.koenig@amd.com> Reviewed-by: Sunil Khatri <sunil.khatri@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
-rw-r--r--drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c10
-rw-r--r--drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h11
2 files changed, 7 insertions, 14 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
index 42f616c05f50..a6e28fe3f8d6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
@@ -109,21 +109,17 @@ int amdgpu_ring_alloc(struct amdgpu_ring *ring, unsigned int ndw)
void amdgpu_ring_insert_nop(struct amdgpu_ring *ring, uint32_t count)
{
uint32_t occupied, chunk1, chunk2;
- uint32_t *dst;
occupied = ring->wptr & ring->buf_mask;
- dst = (void *)&ring->ring[occupied];
chunk1 = ring->buf_mask + 1 - occupied;
chunk1 = (chunk1 >= count) ? count : chunk1;
chunk2 = count - chunk1;
if (chunk1)
- memset32(dst, ring->funcs->nop, chunk1);
+ memset32(&ring->ring[occupied], ring->funcs->nop, chunk1);
- if (chunk2) {
- dst = (void *)ring->ring;
- memset32(dst, ring->funcs->nop, chunk2);
- }
+ if (chunk2)
+ memset32(ring->ring, ring->funcs->nop, chunk2);
ring->wptr += count;
ring->wptr &= ring->ptr_mask;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
index 574336d6714a..36fc9578c53c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
@@ -246,7 +246,7 @@ struct amdgpu_ring {
struct drm_gpu_scheduler sched;
struct amdgpu_bo *ring_obj;
- volatile uint32_t *ring;
+ uint32_t *ring;
unsigned rptr_offs;
u64 rptr_gpu_addr;
volatile u32 *rptr_cpu_addr;
@@ -288,7 +288,7 @@ struct amdgpu_ring {
u64 cond_exe_gpu_addr;
volatile u32 *cond_exe_cpu_addr;
unsigned int set_q_mode_offs;
- volatile u32 *set_q_mode_ptr;
+ u32 *set_q_mode_ptr;
u64 set_q_mode_token;
unsigned vm_hub;
unsigned vm_inv_eng;
@@ -386,10 +386,8 @@ static inline void amdgpu_ring_write_multiple(struct amdgpu_ring *ring,
void *src, int count_dw)
{
unsigned occupied, chunk1, chunk2;
- void *dst;
occupied = ring->wptr & ring->buf_mask;
- dst = (void *)&ring->ring[occupied];
chunk1 = ring->buf_mask + 1 - occupied;
chunk1 = (chunk1 >= count_dw) ? count_dw : chunk1;
chunk2 = count_dw - chunk1;
@@ -397,12 +395,11 @@ static inline void amdgpu_ring_write_multiple(struct amdgpu_ring *ring,
chunk2 <<= 2;
if (chunk1)
- memcpy(dst, src, chunk1);
+ memcpy(&ring->ring[occupied], src, chunk1);
if (chunk2) {
src += chunk1;
- dst = (void *)ring->ring;
- memcpy(dst, src, chunk2);
+ memcpy(ring->ring, src, chunk2);
}
ring->wptr += count_dw;