From: Ankitprasad Sharma <ankitprasad.r.sharma@xxxxxxxxx>
This patch adds support for clearing buffer objects via CPU/GTT. This
is particularly useful for clearing out the non shmem backed objects.
Currently intend to use this only for buffers allocated from stolen
region.
v2: Added kernel doc for i915_gem_clear_object(), corrected/removed
variable assignments (Tvrtko)
Testcase: igt/gem_stolen
Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@xxxxxxxxx>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_gem.c | 39 +++++++++++++++++++++++++++++++++++++++
2 files changed, 40 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 548a0eb..39b29d3 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2856,6 +2856,7 @@ int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj,
int *needs_clflush);
int __must_check i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
+int i915_gem_clear_object(struct drm_i915_gem_object *obj);
static inline int __sg_page_count(struct scatterlist *sg)
{
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 9d2e6e3..645b8a0 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -5244,3 +5244,42 @@ fail:
drm_gem_object_unreference(&obj->base);
return ERR_PTR(ret);
}
+
+/**
+ * i915_gem_clear_object() - Clear buffer object via CPU/GTT
+ * @obj: Buffer object to be cleared
+ *
+ * Return: 0 - success, non-zero - failure
+ */
+int i915_gem_clear_object(struct drm_i915_gem_object *obj)
+{
+ int ret;
+ char __iomem *base;
+ size_t size = obj->base.size;
+ struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
+
+ WARN_ON(!mutex_is_locked(&obj->base.dev->struct_mutex));
+ ret = i915_gem_obj_ggtt_pin(obj, 0, PIN_MAPPABLE);
+ if (ret)
+ return ret;
+
+ ret = i915_gem_object_put_fence(obj);
+ if (ret)
+ goto unpin;
+
+ /* Get the CPU virtual address of the buffer */
+ base = ioremap_wc(dev_priv->gtt.mappable_base +
+ i915_gem_obj_ggtt_offset(obj), size);
+ if (base == NULL) {
+ DRM_ERROR("Mapping of gem object to CPU failed!\n");
+ ret = -ENOSPC;
+ goto unpin;
+ }
+
+ memset_io(base, 0, size);
+
+ iounmap(base);
+unpin:
+ i915_gem_object_ggtt_unpin(obj);
+ return ret;
+}
--
1.9.1
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