[PATCH 4/5] 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 | 15 +++++++++++++++
 drivers/gpu/drm/i915/i915_drv.c          |  1 +
 drivers/gpu/drm/i915/i915_drv.h          |  2 ++
 3 files changed, 18 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index a3eb194fd3b4..ef151a639b74 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -566,6 +566,21 @@ static int gem_mmap_offset(struct drm_device *dev, void *data,
 					     &args->offset);
 }
 
+int
+i915_gem_mmap_dumb(struct drm_file *file,
+		  struct drm_device *dev,
+		  u32 handle,
+		  u64 *offset)
+{
+	struct drm_i915_private *i915 = to_i915(dev);
+	enum i915_mmap_type mmap_type = (!boot_cpu_has(X86_FEATURE_PAT) &&
+					 HAS_MAPPABLE_APERTURE(i915)) ?
+		I915_MMAP_TYPE_GTT : I915_MMAP_TYPE_WC;
+
+	return __assign_gem_object_mmap_data(file, handle, mmap_type,
+					     offset);
+}
+
 /**
  * i915_gem_mmap_gtt_ioctl - prepare an object for GTT mmap'ing
  * @dev: DRM device
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index ead2e6ca7907..2157bc961e1f 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -2752,6 +2752,7 @@ 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,
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a407ca62888b..800674d167a5 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1934,6 +1934,8 @@ i915_mutex_lock_interruptible(struct drm_device *dev)
 int i915_gem_dumb_create(struct drm_file *file_priv,
 			 struct drm_device *dev,
 			 struct drm_mode_create_dumb *args);
+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);
 
 int __must_check i915_gem_set_global_seqno(struct drm_device *dev, u32 seqno);
-- 
2.23.0