drm/radeon/kms: Add support for multi-ring sync in CS ioctl (v2)

Use semaphores to sync buffers across rings in the CS
ioctl.  Add a reloc flag to allow userspace to skip
sync for buffers.

agd5f: port to latest CS ioctl changes.

v2: add ring lock/unlock to make sure changes hit the ring.

Signed-off-by: Christian König <deathsimple@vodafone.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

3 files changed, 50 insertions, 0 deletions

diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 5e3542384b2..3483ed9b38e 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -230,6 +230,7 @@ struct radeon_fence {
         bool                            signaled;
         /* RB, DMA, etc. */
         int                             ring;
+        struct radeon_semaphore         *semaphore;
 };
 
 int radeon_fence_driver_start_ring(struct radeon_device *rdev, int ring);
@@ -789,6 +790,7 @@ struct radeon_cs_parser {
         struct radeon_cs_reloc  *relocs;
         struct radeon_cs_reloc  **relocs_ptr;
         struct list_head        validated;
+        bool                    sync_to_ring[RADEON_NUM_RINGS];
         /* indices of various chunks */
         int                     chunk_ib_idx;
         int                     chunk_relocs_idx;
diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
index 4d595403b50..17af0e83c32 100644
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -84,6 +84,13 @@ int radeon_cs_parser_relocs(struct radeon_cs_parser *p)
                         p->relocs[i].flags = r->flags;
                         radeon_bo_list_add_object(&p->relocs[i].lobj,
                                                   &p->validated);
+
+                        if (p->relocs[i].robj->tbo.sync_obj && !(r->flags & RADEON_RELOC_DONT_SYNC)) {
+                                struct radeon_fence *fence = p->relocs[i].robj->tbo.sync_obj;
+                                if (!radeon_fence_signaled(fence)) {
+                                        p->sync_to_ring[fence->ring] = true;
+                                }
+                        }
                 } else
                         p->relocs[i].handle = 0;
         }
@@ -109,6 +116,36 @@ static int radeon_cs_get_ring(struct radeon_cs_parser *p, u32 ring, s32 priority
         return 0;
 }
 
+static int radeon_cs_sync_rings(struct radeon_cs_parser *p)
+{
+        int i, r;
+
+        for (i = 0; i < RADEON_NUM_RINGS; ++i) {
+                /* no need to sync to our own or unused rings */
+                if (i == p->ring || !p->sync_to_ring[i] || !p->rdev->ring[i].ready)
+                        continue;
+
+                if (!p->ib->fence->semaphore) {
+                        r = radeon_semaphore_create(p->rdev, &p->ib->fence->semaphore);
+                        if (r)
+                                return r;
+                }
+
+                r = radeon_ring_lock(p->rdev, &p->rdev->ring[i], 3);
+                if (r)
+                        return r;
+                radeon_semaphore_emit_signal(p->rdev, i, p->ib->fence->semaphore);
+                radeon_ring_unlock_commit(p->rdev, &p->rdev->ring[i]);
+
+                r = radeon_ring_lock(p->rdev, &p->rdev->ring[p->ring], 3);
+                if (r)
+                        return r;
+                radeon_semaphore_emit_wait(p->rdev, p->ring, p->ib->fence->semaphore);
+                radeon_ring_unlock_commit(p->rdev, &p->rdev->ring[p->ring]);
+        }
+        return 0;
+}
+
 int radeon_cs_parser_init(struct radeon_cs_parser *p, void *data)
 {
         struct drm_radeon_cs *cs = data;
@@ -314,6 +351,10 @@ static int radeon_cs_ib_chunk(struct radeon_device *rdev,
                 DRM_ERROR("Invalid command stream !\n");
                 return r;
         }
+        r = radeon_cs_sync_rings(parser);
+        if (r) {
+                DRM_ERROR("Failed to synchronize rings !\n");
+        }
         parser->ib->vm_id = 0;
         r = radeon_ib_schedule(rdev, parser->ib);
         if (r) {
@@ -384,6 +425,10 @@ static int radeon_cs_ib_vm_chunk(struct radeon_device *rdev,
         if (r) {
                 goto out;
         }
+        r = radeon_cs_sync_rings(parser);
+        if (r) {
+                DRM_ERROR("Failed to synchronize rings !\n");
+        }
         parser->ib->vm_id = vm->id;
         /* ib pool is bind at 0 in virtual address space to gpu_addr is the
          * offset inside the pool bo
diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
index ae9e3da594a..64ea3dd9e6f 100644
--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -153,6 +153,8 @@ static void radeon_fence_destroy(struct kref *kref)
         list_del(&fence->list);
         fence->emitted = false;
         write_unlock_irqrestore(&fence->rdev->fence_lock, irq_flags);
+        if (fence->semaphore)
+                radeon_semaphore_free(fence->rdev, fence->semaphore);
         kfree(fence);
 }
 
@@ -172,6 +174,7 @@ int radeon_fence_create(struct radeon_device *rdev,
         (*fence)->signaled = false;
         (*fence)->seq = 0;
         (*fence)->ring = ring;
+        (*fence)->semaphore = NULL;
         INIT_LIST_HEAD(&(*fence)->list);
 
         write_lock_irqsave(&rdev->fence_lock, irq_flags);