drm/panfrost: Add the panfrost_gem_mapping concept

With the introduction of per-FD address space, the same BO can be mapped
in different address space if the BO is globally visible (GEM_FLINK)
and opened in different context or if the dmabuf is self-imported. The
current implementation does not take case into account, and attaches the
mapping directly to the panfrost_gem_object.

Let's create a panfrost_gem_mapping struct and allow multiple mappings
per BO.

The mappings are refcounted which helps solve another problem where
mappings were torn down (GEM handle closed by userspace) while GPU
jobs accessing those BOs were still in-flight. Jobs now keep a
reference on the mappings they use.

v2 (robh):
- Minor review comment clean-ups from Steven
- Use list_is_singular helper
- Just WARN if we add a mapping when madvise state is not WILLNEED.
  With that, drop the use of object_name_lock.

v3 (robh):
- Revert returning list iterator in panfrost_gem_mapping_get()

Fixes: a5efb4c9a562 ("drm/panfrost: Restructure the GEM object creation")
Fixes: 7282f7645d06 ("drm/panfrost: Implement per FD address spaces")
Cc: <stable@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200116021554.15090-1-robh@kernel.org

1 files changed, 22 insertions, 12 deletions

diff --git a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
index 2c04e858c50a..684820448be3 100644
--- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
+++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
@@ -25,7 +25,7 @@
 #define V4_SHADERS_PER_COREGROUP	4
 
 struct panfrost_perfcnt {
-	struct panfrost_gem_object *bo;
+	struct panfrost_gem_mapping *mapping;
 	size_t bosize;
 	void *buf;
 	struct panfrost_file_priv *user;
@@ -49,7 +49,7 @@ static int panfrost_perfcnt_dump_locked(struct panfrost_device *pfdev)
 	int ret;
 
 	reinit_completion(&pfdev->perfcnt->dump_comp);
-	gpuva = pfdev->perfcnt->bo->node.start << PAGE_SHIFT;
+	gpuva = pfdev->perfcnt->mapping->mmnode.start << PAGE_SHIFT;
 	gpu_write(pfdev, GPU_PERFCNT_BASE_LO, gpuva);
 	gpu_write(pfdev, GPU_PERFCNT_BASE_HI, gpuva >> 32);
 	gpu_write(pfdev, GPU_INT_CLEAR,
@@ -89,17 +89,22 @@ static int panfrost_perfcnt_enable_locked(struct panfrost_device *pfdev,
 	if (IS_ERR(bo))
 		return PTR_ERR(bo);
 
-	perfcnt->bo = to_panfrost_bo(&bo->base);
-
 	/* Map the perfcnt buf in the address space attached to file_priv. */
-	ret = panfrost_gem_open(&perfcnt->bo->base.base, file_priv);
+	ret = panfrost_gem_open(&bo->base, file_priv);
 	if (ret)
 		goto err_put_bo;
 
+	perfcnt->mapping = panfrost_gem_mapping_get(to_panfrost_bo(&bo->base),
+						    user);
+	if (!perfcnt->mapping) {
+		ret = -EINVAL;
+		goto err_close_bo;
+	}
+
 	perfcnt->buf = drm_gem_shmem_vmap(&bo->base);
 	if (IS_ERR(perfcnt->buf)) {
 		ret = PTR_ERR(perfcnt->buf);
-		goto err_close_bo;
+		goto err_put_mapping;
 	}
 
 	/*
@@ -154,12 +159,17 @@ static int panfrost_perfcnt_enable_locked(struct panfrost_device *pfdev,
 	if (panfrost_has_hw_issue(pfdev, HW_ISSUE_8186))
 		gpu_write(pfdev, GPU_PRFCNT_TILER_EN, 0xffffffff);
 
+	/* The BO ref is retained by the mapping. */
+	drm_gem_object_put_unlocked(&bo->base);
+
 	return 0;
 
 err_vunmap:
-	drm_gem_shmem_vunmap(&perfcnt->bo->base.base, perfcnt->buf);
+	drm_gem_shmem_vunmap(&bo->base, perfcnt->buf);
+err_put_mapping:
+	panfrost_gem_mapping_put(perfcnt->mapping);
 err_close_bo:
-	panfrost_gem_close(&perfcnt->bo->base.base, file_priv);
+	panfrost_gem_close(&bo->base, file_priv);
 err_put_bo:
 	drm_gem_object_put_unlocked(&bo->base);
 	return ret;
@@ -182,11 +192,11 @@ static int panfrost_perfcnt_disable_locked(struct panfrost_device *pfdev,
 		  GPU_PERFCNT_CFG_MODE(GPU_PERFCNT_CFG_MODE_OFF));
 
 	perfcnt->user = NULL;
-	drm_gem_shmem_vunmap(&perfcnt->bo->base.base, perfcnt->buf);
+	drm_gem_shmem_vunmap(&perfcnt->mapping->obj->base.base, perfcnt->buf);
 	perfcnt->buf = NULL;
-	panfrost_gem_close(&perfcnt->bo->base.base, file_priv);
-	drm_gem_object_put_unlocked(&perfcnt->bo->base.base);
-	perfcnt->bo = NULL;
+	panfrost_gem_close(&perfcnt->mapping->obj->base.base, file_priv);
+	panfrost_gem_mapping_put(perfcnt->mapping);
+	perfcnt->mapping = NULL;
 	pm_runtime_mark_last_busy(pfdev->dev);
 	pm_runtime_put_autosuspend(pfdev->dev);