[Intel-gfx] [RFC 1/2] drm: Add aux plane verification in addFB2

[Vandana Kannan]

From: Daniel Vetter <daniel.vetter at ffwll.ch>

For render compression, userspace passes aux stride and offset values as an
additional entry in the fb structure. This should not be treated as garbage
and discarded as data belonging to no plane.
This patch introduces a check related to AUX plane to support the
scenario of render compression.

v2: Based on a discussion with Siva
Move num_planes check below the increment.

Signed-off-by: Daniel Vetter <daniel at ffwll.ch>
Signed-off-by: Vandana Kannan <vandana.kannan at intel.com>
Cc: Sivakumar Thulasimani <sivakumar.thulasimani at intel.com>
---
 drivers/gpu/drm/drm_crtc.c  | 19 ++++++++++++++++++-
 drivers/gpu/drm/drm_ioctl.c |  3 +++
 include/drm/drm_crtc.h      |  3 +++
 include/uapi/drm/drm.h      |  1 +
 include/uapi/drm/drm_mode.h |  1 +
 5 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 32dd134..8b79ff8 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3204,6 +3204,16 @@ static int framebuffer_check(const struct drm_mode_fb_cmd2 *r)
 		}
 	}
 
+	if (r->flags & DRM_MODE_FB_AUX_PLANE) {
+		num_planes++;
+
+		if (num_planes == 4) {
+			DRM_DEBUG_KMS("Number of planes cannot exceed 3"
+					"(including aux plane)\n");
+			return -EINVAL;
+		}
+	}
+
 	for (i = num_planes; i < 4; i++) {
 		if (r->modifier[i]) {
 			DRM_DEBUG_KMS("non-zero modifier for unused plane %d\n", i);
@@ -3242,7 +3252,8 @@ internal_framebuffer_create(struct drm_device *dev,
 	struct drm_framebuffer *fb;
 	int ret;
 
-	if (r->flags & ~(DRM_MODE_FB_INTERLACED | DRM_MODE_FB_MODIFIERS)) {
+	if (r->flags & ~(DRM_MODE_FB_INTERLACED | DRM_MODE_FB_MODIFIERS |
+		DRM_MODE_FB_AUX_PLANE)) {
 		DRM_DEBUG_KMS("bad framebuffer flags 0x%08x\n", r->flags);
 		return ERR_PTR(-EINVAL);
 	}
@@ -3264,6 +3275,12 @@ internal_framebuffer_create(struct drm_device *dev,
 		return ERR_PTR(-EINVAL);
 	}
 
+	if (r->flags & DRM_MODE_FB_AUX_PLANE &&
+	    !dev->mode_config.allow_aux_plane) {
+		DRM_DEBUG_KMS("driver does not support render compression\n");
+		return ERR_PTR(-EINVAL);
+	}
+
 	ret = framebuffer_check(r);
 	if (ret)
 		return ERR_PTR(ret);
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index 8ce2a0c..ee00782 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -312,6 +312,9 @@ static int drm_getcap(struct drm_device *dev, void *data, struct drm_file *file_
 	case DRM_CAP_ADDFB2_MODIFIERS:
 		req->value = dev->mode_config.allow_fb_modifiers;
 		break;
+	case DRM_CAP_RENDER_COMPRESSION:
+		req->value = dev->mode_config.allow_aux_plane;
+		break;
 	default:
 		return -EINVAL;
 	}
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 4765df3..533d0cd 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -1156,6 +1156,9 @@ struct drm_mode_config {
 	/* whether the driver supports fb modifiers */
 	bool allow_fb_modifiers;
 
+	/* whether the driver supports render compression */
+	bool allow_aux_plane;
+
 	/* cursor size */
 	uint32_t cursor_width, cursor_height;
 };
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 3801584..0834bf7 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -631,6 +631,7 @@ struct drm_gem_open {
 #define DRM_CAP_CURSOR_WIDTH		0x8
 #define DRM_CAP_CURSOR_HEIGHT		0x9
 #define DRM_CAP_ADDFB2_MODIFIERS	0x10
+#define DRM_CAP_RENDER_COMPRESSION	0x11
 
 /** DRM_IOCTL_GET_CAP ioctl argument type */
 struct drm_get_cap {
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 6c11ca4..de59ace 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -354,6 +354,7 @@ struct drm_mode_fb_cmd {
 
 #define DRM_MODE_FB_INTERLACED	(1<<0) /* for interlaced framebuffers */
 #define DRM_MODE_FB_MODIFIERS	(1<<1) /* enables ->modifer[] */
+#define DRM_MODE_FB_AUX_PLANE   (1<<2) /* for compressed buffer */
 
 struct drm_mode_fb_cmd2 {
 	__u32 fb_id;
-- 
1.9.1