drm/i915: Perform relocations in CPU domain [if in CPU domain]

Avoid an early eviction of the batch buffer into the uncached GTT
domain, and so do the relocation fixup in cacheable memory.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 67998e8a2d7010928ce688fd9049f7133d5fcfc7..32ff571672b4ba21b92c1a1ddb63a9fc9290856f 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3124,9 +3124,6 @@ i915_gem_object_set_to_gpu_domain(struct drm_gem_object *obj)
        uint32_t                        flush_domains = 0;
        uint32_t                        old_read_domains;
 
-       BUG_ON(obj->pending_read_domains & I915_GEM_DOMAIN_CPU);
-       BUG_ON(obj->pending_write_domain == I915_GEM_DOMAIN_CPU);
-
        intel_mark_busy(dev, obj);
 
        /*
@@ -3298,7 +3295,6 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
        struct drm_i915_gem_object *obj_priv = to_intel_bo(obj);
        struct drm_i915_gem_relocation_entry __user *user_relocs;
        int i, ret;
-       void __iomem *reloc_page;
        bool need_fence;
 
        need_fence = entry->flags & EXEC_OBJECT_NEEDS_FENCE &&
@@ -3342,8 +3338,6 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                struct drm_i915_gem_relocation_entry reloc;
                struct drm_gem_object *target_obj;
                struct drm_i915_gem_object *target_obj_priv;
-               uint32_t reloc_val, reloc_offset;
-               uint32_t __iomem *reloc_entry;
 
                ret = __copy_from_user_inatomic(&reloc,
                                                user_relocs+i,
@@ -3469,27 +3463,36 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                        return -EINVAL;
                }
 
-               ret = i915_gem_object_set_to_gtt_domain(obj, 1);
-               if (ret != 0) {
-                       drm_gem_object_unreference(target_obj);
-                       i915_gem_object_unpin(obj);
-                       return ret;
-               }
+               reloc.delta += target_obj_priv->gtt_offset;
+               if (obj->write_domain == I915_GEM_DOMAIN_CPU) {
+                       uint32_t page_offset = reloc.offset & ~PAGE_MASK;
+                       char *vaddr;
 
-               /* Map the page containing the relocation we're going to
-                * perform.
-                */
-               reloc_offset = obj_priv->gtt_offset + reloc.offset;
-               reloc_page = io_mapping_map_atomic_wc(dev_priv->mm.gtt_mapping,
-                                                     (reloc_offset &
-                                                      ~(PAGE_SIZE - 1)),
-                                                     KM_USER0);
-               reloc_entry = (uint32_t __iomem *)(reloc_page +
-                                                  (reloc_offset & (PAGE_SIZE - 1)));
-               reloc_val = target_obj_priv->gtt_offset + reloc.delta;
-
-               writel(reloc_val, reloc_entry);
-               io_mapping_unmap_atomic(reloc_page, KM_USER0);
+                       vaddr = kmap_atomic(obj_priv->pages[reloc.offset >> PAGE_SHIFT], KM_USER0);
+                       *(uint32_t *)(vaddr + page_offset) = reloc.delta;
+                       kunmap_atomic(vaddr, KM_USER0);
+               } else {
+                       uint32_t __iomem *reloc_entry;
+                       void __iomem *reloc_page;
+                       int ret;
+
+                       ret = i915_gem_object_set_to_gtt_domain(obj, 1);
+                       if (ret) {
+                               drm_gem_object_unreference(target_obj);
+                               i915_gem_object_unpin(obj);
+                               return ret;
+                       }
+
+                       /* Map the page containing the relocation we're going to perform.  */
+                       reloc.offset += obj_priv->gtt_offset;
+                       reloc_page = io_mapping_map_atomic_wc(dev_priv->mm.gtt_mapping,
+                                                             reloc.offset & PAGE_MASK,
+                                                             KM_USER0);
+                       reloc_entry = (uint32_t __iomem *)
+                               (reloc_page + (reloc.offset & ~PAGE_MASK));
+                       iowrite32(reloc.delta, reloc_entry);
+                       io_mapping_unmap_atomic(reloc_page, KM_USER0);
+               }
 
                drm_gem_object_unreference(target_obj);
        }