[RFC PATCH v2 1/8] drm/amdgpu/uapi: Introduce AMDGPU_GEM_DOMAIN_MMIO_REMAP

[Srinivasan Shanmugam]

Add a new GEM domain bit AMDGPU_GEM_DOMAIN_MMIO_REMAP to allow
userspace to request the MMIO remap (HDP flush) page via GEM_CREATE.

- include/uapi/drm/amdgpu_drm.h:
  * define AMDGPU_GEM_DOMAIN_MMIO_REMAP
  * include the bit in AMDGPU_GEM_DOMAIN_MASK

v2: Add early reject in amdgpu_gem_create_ioctl() (Alex).

Cc: Christian König <christian.koenig at amd.com>
Suggested-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 3 +++
 include/uapi/drm/amdgpu_drm.h           | 8 ++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index e3f65977eeee..d8cffd26455b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -464,6 +464,9 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev, void *data,
 
 	/* always clear VRAM */
 	flags |= AMDGPU_GEM_CREATE_VRAM_CLEARED;
+	
+	if (args->in.domains & AMDGPU_GEM_DOMAIN_MMIO_REMAP)
+		return -EINVAL;
 
 	/* create a gem object to contain this object in */
 	if (args->in.domains & (AMDGPU_GEM_DOMAIN_GDS |
diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
index bdedbaccf776..fc44e301adbb 100644
--- a/include/uapi/drm/amdgpu_drm.h
+++ b/include/uapi/drm/amdgpu_drm.h
@@ -103,6 +103,8 @@ extern "C" {
  *
  * %AMDGPU_GEM_DOMAIN_DOORBELL	Doorbell. It is an MMIO region for
  * signalling user mode queues.
+ *
+ * %AMDGPU_GEM_DOMAIN_MMIO_REMAP	MMIO remap page (special mapping for HDP flushing).
  */
 #define AMDGPU_GEM_DOMAIN_CPU		0x1
 #define AMDGPU_GEM_DOMAIN_GTT		0x2
@@ -111,13 +113,15 @@ extern "C" {
 #define AMDGPU_GEM_DOMAIN_GWS		0x10
 #define AMDGPU_GEM_DOMAIN_OA		0x20
 #define AMDGPU_GEM_DOMAIN_DOORBELL	0x40
+#define AMDGPU_GEM_DOMAIN_MMIO_REMAP	0x80
 #define AMDGPU_GEM_DOMAIN_MASK		(AMDGPU_GEM_DOMAIN_CPU | \
 					 AMDGPU_GEM_DOMAIN_GTT | \
 					 AMDGPU_GEM_DOMAIN_VRAM | \
 					 AMDGPU_GEM_DOMAIN_GDS | \
 					 AMDGPU_GEM_DOMAIN_GWS | \
-					 AMDGPU_GEM_DOMAIN_OA | \
-					 AMDGPU_GEM_DOMAIN_DOORBELL)
+					 AMDGPU_GEM_DOMAIN_OA |	\
+					 AMDGPU_GEM_DOMAIN_DOORBELL | \
+					 AMDGPU_GEM_DOMAIN_MMIO_REMAP)
 
 /* Flag that CPU access will be required for the case of VRAM domain */
 #define AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED	(1 << 0)
-- 
2.34.1