[PATCH 4/4] drm/msm/a6xx: Zap counters across context switch

From: Rob Clark
Date: Thu Mar 03 2022 - 19:59:21 EST


From: Rob Clark <robdclark@xxxxxxxxxxxx>

Any app controlled perfcntr collection (GL_AMD_performance_monitor, etc)
does not require counters to maintain state across context switches. So
clear them if systemwide profiling is not active.

Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
---
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 29 +++++++++++++++++++++++++++
1 file changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 237c2e7a7baa..02b47977b5c3 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -101,6 +101,7 @@ static void get_stats_counter(struct msm_ringbuffer *ring, u32 counter,
static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
struct msm_ringbuffer *ring, struct msm_file_private *ctx)
{
+ bool sysprof = refcount_read(&a6xx_gpu->base.base.sysprof_active) > 1;
phys_addr_t ttbr;
u32 asid;
u64 memptr = rbmemptr(ring, ttbr0);
@@ -111,6 +112,15 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,
if (msm_iommu_pagetable_params(ctx->aspace->mmu, &ttbr, &asid))
return;

+ if (!sysprof) {
+ /* Turn off protected mode to write to special registers */
+ OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
+ OUT_RING(ring, 0);
+
+ OUT_PKT4(ring, REG_A6XX_RBBM_PERFCTR_SRAM_INIT_CMD, 1);
+ OUT_RING(ring, 1);
+ }
+
/* Execute the table update */
OUT_PKT7(ring, CP_SMMU_TABLE_UPDATE, 4);
OUT_RING(ring, CP_SMMU_TABLE_UPDATE_0_TTBR0_LO(lower_32_bits(ttbr)));
@@ -137,6 +147,25 @@ static void a6xx_set_pagetable(struct a6xx_gpu *a6xx_gpu,

OUT_PKT7(ring, CP_EVENT_WRITE, 1);
OUT_RING(ring, 0x31);
+
+ if (!sysprof) {
+ /*
+ * Wait for SRAM clear after the pgtable update, so the
+ * two can happen in parallel:
+ */
+ OUT_PKT7(ring, CP_WAIT_REG_MEM, 6);
+ OUT_RING(ring, CP_WAIT_REG_MEM_0_FUNCTION(WRITE_EQ));
+ OUT_RING(ring, CP_WAIT_REG_MEM_1_POLL_ADDR_LO(
+ REG_A6XX_RBBM_PERFCTR_SRAM_INIT_STATUS));
+ OUT_RING(ring, CP_WAIT_REG_MEM_2_POLL_ADDR_HI(0));
+ OUT_RING(ring, CP_WAIT_REG_MEM_3_REF(0x1));
+ OUT_RING(ring, CP_WAIT_REG_MEM_4_MASK(0x1));
+ OUT_RING(ring, CP_WAIT_REG_MEM_5_DELAY_LOOP_CYCLES(0));
+
+ /* Re-enable protected mode: */
+ OUT_PKT7(ring, CP_SET_PROTECTED_MODE, 1);
+ OUT_RING(ring, 1);
+ }
}

static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
--
2.35.1