drm/amdgpu: sync ce and me with SWITCH_BUFFER(2)

we used to adopt wait_reg_mem to let CE wait before DE finish page
updating, but from Tonga+, CE doesn't support wait_reg_mem package so
this logic no longer works.

so here is another approach to do same thing:
Insert two of SWITCH_BUFFER at both front and end of vm_flush can
guarantee that CE not go further to process IB_const before vm_flush
done.

Insert two of SWITCH_BUFFER also works on CI, so remove legency method
to sync CE and ME

v2:
Insert double SWITCH_BUFFER at front of vm flush as well.

Signed-off-by: monk.liu <monk.liu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>

3 files changed, 23 insertions, 92 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 57b427f958da..6647fb26ef25 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -1202,8 +1202,6 @@ struct amdgpu_gfx {
         struct amdgpu_irq_src           priv_inst_irq;
         /* gfx status */
         uint32_t gfx_current_status;
-        /* sync signal for const engine */
-        unsigned ce_sync_offs;
         /* ce ram size*/
         unsigned ce_ram_size;
 };
diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c
index 392ec10cc475..e992bf2ff66c 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c
@@ -3610,41 +3610,6 @@ static int gfx_v7_0_cp_resume(struct amdgpu_device *adev)
         return 0;
 }
 
-static void gfx_v7_0_ce_sync_me(struct amdgpu_ring *ring)
-{
-        struct amdgpu_device *adev = ring->adev;
-        u64 gpu_addr = adev->wb.gpu_addr + adev->gfx.ce_sync_offs * 4;
-
-        /* instruct DE to set a magic number */
-        amdgpu_ring_write(ring, PACKET3(PACKET3_WRITE_DATA, 3));
-        amdgpu_ring_write(ring, (WRITE_DATA_ENGINE_SEL(0) |
-                                                         WRITE_DATA_DST_SEL(5)));
-        amdgpu_ring_write(ring, gpu_addr & 0xfffffffc);
-        amdgpu_ring_write(ring, upper_32_bits(gpu_addr) & 0xffffffff);
-        amdgpu_ring_write(ring, 1);
-
-        /* let CE wait till condition satisfied */
-        amdgpu_ring_write(ring, PACKET3(PACKET3_WAIT_REG_MEM, 5));
-        amdgpu_ring_write(ring, (WAIT_REG_MEM_OPERATION(0) | /* wait */
-                                                         WAIT_REG_MEM_MEM_SPACE(1) | /* memory */
-                                                         WAIT_REG_MEM_FUNCTION(3) |  /* == */
-                                                         WAIT_REG_MEM_ENGINE(2)));   /* ce */
-        amdgpu_ring_write(ring, gpu_addr & 0xfffffffc);
-        amdgpu_ring_write(ring, upper_32_bits(gpu_addr) & 0xffffffff);
-        amdgpu_ring_write(ring, 1);
-        amdgpu_ring_write(ring, 0xffffffff);
-        amdgpu_ring_write(ring, 4); /* poll interval */
-
-        /* instruct CE to reset wb of ce_sync to zero */
-        amdgpu_ring_write(ring, PACKET3(PACKET3_WRITE_DATA, 3));
-        amdgpu_ring_write(ring, (WRITE_DATA_ENGINE_SEL(2) |
-                                                         WRITE_DATA_DST_SEL(5) |
-                                                         WR_CONFIRM));
-        amdgpu_ring_write(ring, gpu_addr & 0xfffffffc);
-        amdgpu_ring_write(ring, upper_32_bits(gpu_addr) & 0xffffffff);
-        amdgpu_ring_write(ring, 0);
-}
-
 /*
  * vm
  * VMID 0 is the physical GPU addresses as used by the kernel.
@@ -3663,6 +3628,13 @@ static void gfx_v7_0_ring_emit_vm_flush(struct amdgpu_ring *ring,
                                         unsigned vm_id, uint64_t pd_addr)
 {
         int usepfp = (ring->type == AMDGPU_RING_TYPE_GFX);
+        if (usepfp) {
+                /* synce CE with ME to prevent CE fetch CEIB before context switch done */
+                amdgpu_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER, 0));
+                amdgpu_ring_write(ring, 0);
+                amdgpu_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER, 0));
+                amdgpu_ring_write(ring, 0);
+        }
 
         amdgpu_ring_write(ring, PACKET3(PACKET3_WRITE_DATA, 3));
         amdgpu_ring_write(ring, (WRITE_DATA_ENGINE_SEL(usepfp) |
@@ -3703,7 +3675,10 @@ static void gfx_v7_0_ring_emit_vm_flush(struct amdgpu_ring *ring,
                 amdgpu_ring_write(ring, 0x0);
 
                 /* synce CE with ME to prevent CE fetch CEIB before context switch done */
-                gfx_v7_0_ce_sync_me(ring);
+                amdgpu_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER, 0));
+                amdgpu_ring_write(ring, 0);
+                amdgpu_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER, 0));
+                amdgpu_ring_write(ring, 0);
         }
 }
 
@@ -4805,12 +4780,6 @@ static int gfx_v7_0_sw_init(void *handle)
                 return r;
         }
 
-        r = amdgpu_wb_get(adev, &adev->gfx.ce_sync_offs);
-        if (r) {
-                DRM_ERROR("(%d) gfx.ce_sync_offs wb alloc failed\n", r);
-                return r;
-        }
-
         for (i = 0; i < adev->gfx.num_gfx_rings; i++) {
                 ring = &adev->gfx.gfx_ring[i];
                 ring->ring_obj = NULL;
@@ -4889,8 +4858,6 @@ static int gfx_v7_0_sw_fini(void *handle)
         for (i = 0; i < adev->gfx.num_compute_rings; i++)
                 amdgpu_ring_fini(&adev->gfx.compute_ring[i]);
 
-        amdgpu_wb_free(adev, adev->gfx.ce_sync_offs);
-
         gfx_v7_0_cp_compute_fini(adev);
         gfx_v7_0_rlc_fini(adev);
         gfx_v7_0_mec_fini(adev);
diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
index 78e5900d71cd..cb4f68f53f24 100644
--- a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
+++ b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
@@ -940,12 +940,6 @@ static int gfx_v8_0_sw_init(void *handle)
                 return r;
         }
 
-        r = amdgpu_wb_get(adev, &adev->gfx.ce_sync_offs);
-        if (r) {
-                DRM_ERROR("(%d) gfx.ce_sync_offs wb alloc failed\n", r);
-                return r;
-        }
-
         /* set up the gfx ring */
         for (i = 0; i < adev->gfx.num_gfx_rings; i++) {
                 ring = &adev->gfx.gfx_ring[i];
@@ -1033,8 +1027,6 @@ static int gfx_v8_0_sw_fini(void *handle)
         for (i = 0; i < adev->gfx.num_compute_rings; i++)
                 amdgpu_ring_fini(&adev->gfx.compute_ring[i]);
 
-        amdgpu_wb_free(adev, adev->gfx.ce_sync_offs);
-
         gfx_v8_0_mec_fini(adev);
 
         return 0;
@@ -4006,41 +3998,6 @@ static bool gfx_v8_0_ring_emit_semaphore(struct amdgpu_ring *ring,
         return true;
 }
 
-static void gfx_v8_0_ce_sync_me(struct amdgpu_ring *ring)
-{
-        struct amdgpu_device *adev = ring->adev;
-        u64 gpu_addr = adev->wb.gpu_addr + adev->gfx.ce_sync_offs * 4;
-
-        /* instruct DE to set a magic number */
-        amdgpu_ring_write(ring, PACKET3(PACKET3_WRITE_DATA, 3));
-        amdgpu_ring_write(ring, (WRITE_DATA_ENGINE_SEL(0) |
-                                                         WRITE_DATA_DST_SEL(5)));
-        amdgpu_ring_write(ring, gpu_addr & 0xfffffffc);
-        amdgpu_ring_write(ring, upper_32_bits(gpu_addr) & 0xffffffff);
-        amdgpu_ring_write(ring, 1);
-
-        /* let CE wait till condition satisfied */
-        amdgpu_ring_write(ring, PACKET3(PACKET3_WAIT_REG_MEM, 5));
-        amdgpu_ring_write(ring, (WAIT_REG_MEM_OPERATION(0) | /* wait */
-                                                         WAIT_REG_MEM_MEM_SPACE(1) | /* memory */
-                                                         WAIT_REG_MEM_FUNCTION(3) |  /* == */
-                                                         WAIT_REG_MEM_ENGINE(2)));   /* ce */
-        amdgpu_ring_write(ring, gpu_addr & 0xfffffffc);
-        amdgpu_ring_write(ring, upper_32_bits(gpu_addr) & 0xffffffff);
-        amdgpu_ring_write(ring, 1);
-        amdgpu_ring_write(ring, 0xffffffff);
-        amdgpu_ring_write(ring, 4); /* poll interval */
-
-        /* instruct CE to reset wb of ce_sync to zero */
-        amdgpu_ring_write(ring, PACKET3(PACKET3_WRITE_DATA, 3));
-        amdgpu_ring_write(ring, (WRITE_DATA_ENGINE_SEL(2) |
-                                                         WRITE_DATA_DST_SEL(5) |
-                                                         WR_CONFIRM));
-        amdgpu_ring_write(ring, gpu_addr & 0xfffffffc);
-        amdgpu_ring_write(ring, upper_32_bits(gpu_addr) & 0xffffffff);
-        amdgpu_ring_write(ring, 0);
-}
-
 static void gfx_v8_0_ring_emit_vm_flush(struct amdgpu_ring *ring,
                                         unsigned vm_id, uint64_t pd_addr)
 {
@@ -4057,6 +4014,14 @@ static void gfx_v8_0_ring_emit_vm_flush(struct amdgpu_ring *ring,
         amdgpu_ring_write(ring, 0xffffffff);
         amdgpu_ring_write(ring, 4); /* poll interval */
 
+        if (usepfp) {
+                /* synce CE with ME to prevent CE fetch CEIB before context switch done */
+                amdgpu_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER, 0));
+                amdgpu_ring_write(ring, 0);
+                amdgpu_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER, 0));
+                amdgpu_ring_write(ring, 0);
+        }
+
         amdgpu_ring_write(ring, PACKET3(PACKET3_WRITE_DATA, 3));
         amdgpu_ring_write(ring, (WRITE_DATA_ENGINE_SEL(usepfp) |
                                  WRITE_DATA_DST_SEL(0)) |
@@ -4096,9 +4061,10 @@ static void gfx_v8_0_ring_emit_vm_flush(struct amdgpu_ring *ring,
                 /* sync PFP to ME, otherwise we might get invalid PFP reads */
                 amdgpu_ring_write(ring, PACKET3(PACKET3_PFP_SYNC_ME, 0));
                 amdgpu_ring_write(ring, 0x0);
-
-                /* synce CE with ME to prevent CE fetch CEIB before context switch done */
-                gfx_v8_0_ce_sync_me(ring);
+                amdgpu_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER, 0));
+                amdgpu_ring_write(ring, 0);
+                amdgpu_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER, 0));
+                amdgpu_ring_write(ring, 0);
         }
 }