[Intel-gfx] [PATCH 3/4] drm/i915: cpu-map based dumb buffers

[Abdiel Janulgue]

Prefer CPU WC mmaps via our new mmap offset plumbing otherwise fall-
back to GTT mmaps when hw doesn't support PAT

Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
Cc: Matthew Auld <matthew.auld at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_mman.c | 18 ++++++++++++++++++
 drivers/gpu/drm/i915/gem/i915_gem_mman.h |  2 ++
 drivers/gpu/drm/i915/i915_drv.c          |  1 +
 3 files changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index d2ed8a463672..c1756e4f46b9 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -540,6 +540,24 @@ __assign_gem_object_mmap_data(struct drm_file *file,
 	return ret;
 }
 
+int
+i915_gem_mmap_dumb(struct drm_file *file,
+		  struct drm_device *dev,
+		  u32 handle,
+		  u64 *offset)
+{
+	enum i915_mmap_type mmap_type;
+
+	if (boot_cpu_has(X86_FEATURE_PAT))
+		mmap_type = I915_MMAP_TYPE_WC;
+	else if (!i915_ggtt_has_aperture(&to_i915(dev)->ggtt))
+		return -ENODEV;
+	else
+		mmap_type = I915_MMAP_TYPE_GTT;
+
+	return __assign_gem_object_mmap_data(file, handle, mmap_type, offset);
+}
+
 /**
  * i915_gem_mmap_offset_ioctl - prepare an object for GTT mmap'ing
  * @dev: DRM device
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.h b/drivers/gpu/drm/i915/gem/i915_gem_mman.h
index 4d3b493e853a..6e70b91dabc4 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.h
@@ -24,6 +24,8 @@ void i915_mmap_offset_destroy(struct i915_mmap_offset *mmo, struct mutex *mutex)
 void __i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj);
 void i915_gem_object_release_mmap(struct drm_i915_gem_object *obj);
 void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj);
+int i915_gem_mmap_dumb(struct drm_file *file_priv, struct drm_device *dev,
+		      u32 handle, u64 *offset);
 int i915_gem_mmap_gtt_version(void);
 
 #endif
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index ac6d4470ce75..f7db0bbbe302 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -2767,6 +2767,7 @@ static struct drm_driver driver = {
 	.get_scanout_position = i915_get_crtc_scanoutpos,
 
 	.dumb_create = i915_gem_dumb_create,
+	.dumb_map_offset = i915_gem_mmap_dumb,
 	.ioctls = i915_ioctls,
 	.num_ioctls = ARRAY_SIZE(i915_ioctls),
 	.fops = &i915_driver_fops,
-- 
2.23.0