[PATCH v3 2/3] drm: Connect live source to framebuffers

[Sergei Shtylyov]

From: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>

Introduce a new live source flag for framebuffers. When a framebuffer is
created with that flag set, a live source is associated with the
framebuffer instead of buffer objects. The framebuffer can then be used
with a plane to connect it with the live source.

[Sergei: ported to the modern kernel.]

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>

---
Changes in version 3:
- ported the patch to the modern kernel;
- added my signoff.

 drivers/gpu/drm/drm_framebuffer.c |  134 ++++++++++++++++++++++++++++++--------
 include/uapi/drm/drm_mode.h       |    7 +
 2 files changed, 113 insertions(+), 28 deletions(-)

Index: linux/drivers/gpu/drm/drm_framebuffer.c
===================================================================
--- linux.orig/drivers/gpu/drm/drm_framebuffer.c
+++ linux/drivers/gpu/drm/drm_framebuffer.c
@@ -126,34 +126,18 @@ int drm_mode_addfb(struct drm_device *de
 	return 0;
 }
 
-static int framebuffer_check(const struct drm_mode_fb_cmd2 *r)
+static int framebuffer_check_buffers(const struct drm_mode_fb_cmd2 *r,
+				     int hsub, int vsub)
 {
-	const struct drm_format_info *info;
-	int i;
+	int num_planes, i;
+	unsigned int cpp;
 
-	info = __drm_format_info(r->pixel_format & ~DRM_FORMAT_BIG_ENDIAN);
-	if (!info) {
-		struct drm_format_name_buf format_name;
-		DRM_DEBUG_KMS("bad framebuffer format %s\n",
-		              drm_get_format_name(r->pixel_format,
-		                                  &format_name));
-		return -EINVAL;
-	}
-
-	if (r->width == 0 || r->width % info->hsub) {
-		DRM_DEBUG_KMS("bad framebuffer width %u\n", r->width);
-		return -EINVAL;
-	}
-
-	if (r->height == 0 || r->height % info->vsub) {
-		DRM_DEBUG_KMS("bad framebuffer height %u\n", r->height);
-		return -EINVAL;
-	}
+ 	num_planes = drm_format_num_planes(r->pixel_format);
+	cpp = drm_format_plane_cpp(r->pixel_format, 0);
 
-	for (i = 0; i < info->num_planes; i++) {
-		unsigned int width = r->width / (i != 0 ? info->hsub : 1);
-		unsigned int height = r->height / (i != 0 ? info->vsub : 1);
-		unsigned int cpp = info->cpp[i];
+	for (i = 0; i < num_planes; i++) {
+		unsigned int width = r->width / (i != 0 ? hsub : 1);
+		unsigned int height = r->height / (i != 0 ? vsub : 1);
 
 		if (!r->handles[i]) {
 			DRM_DEBUG_KMS("no buffer object handle for plane %d\n", i);
@@ -203,7 +187,7 @@ static int framebuffer_check(const struc
 		}
 	}
 
-	for (i = info->num_planes; i < 4; i++) {
+	for (i = num_planes; i < 4; i++) {
 		if (r->modifier[i]) {
 			DRM_DEBUG_KMS("non-zero modifier for unused plane %d\n", i);
 			return -EINVAL;
@@ -232,6 +216,99 @@ static int framebuffer_check(const struc
 	return 0;
 }
 
+static int framebuffer_check_sources(struct drm_device *dev,
+				     const struct drm_mode_fb_cmd2 *r)
+{
+	struct drm_mode_object *obj;
+	struct drm_live_source *src;
+	unsigned int cpp;
+	unsigned int i;
+
+	/*
+	 * Ensure that userspace has zeroed unused handles, pitches, offsets and
+	 * modifiers to allow future API extensions.
+	 */
+	if (r->offsets[0] || r->modifier[0])
+		return -EINVAL;
+
+	for (i = 1; i < ARRAY_SIZE(r->handles); ++i) {
+		if (r->handles[i] || r->pitches[i] ||
+		    r->offsets[i] || r->modifier[i])
+			return -EINVAL;
+	}
+
+	/* Validate width, height and pitch. */
+	cpp = drm_format_plane_cpp(r->pixel_format, 0);
+
+	if ((uint64_t) r->width * cpp > UINT_MAX)
+		return -ERANGE;
+
+	if ((uint64_t) r->height * r->pitches[0] > UINT_MAX)
+		return -ERANGE;
+
+	if (r->pitches[0] != r->width * cpp) {
+		DRM_DEBUG_KMS("bad pitch %u for plane %d\n", r->pitches[0], i);
+		return -EINVAL;
+	}
+
+	/*
+	 * Find the live source and check whether it supports the requested
+	 * pixel format.
+	 */
+
+	obj = drm_mode_object_find(dev, r->handles[0],
+				   DRM_MODE_OBJECT_LIVE_SOURCE);
+	if (!obj) {
+		DRM_DEBUG_KMS("bad framebuffer source ID %u\n", r->handles[0]);
+		return -EINVAL;
+	}
+
+	src = obj_to_live_source(obj);
+
+	for (i = 0; i < src->format_count; i++) {
+		if (r->pixel_format == src->format_types[i])
+			break;
+	}
+
+	if (i == src->format_count) {
+		DRM_DEBUG_KMS("bad framebuffer pixel format 0x%08x for source %u\n",
+			      r->pixel_format, r->handles[0]);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int framebuffer_check(struct drm_device *dev,
+			     const struct drm_mode_fb_cmd2 *r)
+{
+	const struct drm_format_info *info;
+
+	info = __drm_format_info(r->pixel_format & ~DRM_FORMAT_BIG_ENDIAN);
+	if (!info) {
+		struct drm_format_name_buf format_name;
+		DRM_DEBUG_KMS("bad framebuffer format %s\n",
+		              drm_get_format_name(r->pixel_format,
+		                                  &format_name));
+		return -EINVAL;
+	}
+
+	if (r->width == 0 || r->width % info->hsub) {
+		DRM_DEBUG_KMS("bad framebuffer width %u\n", r->width);
+		return -EINVAL;
+	}
+
+	if (r->height == 0 || r->height % info->vsub) {
+		DRM_DEBUG_KMS("bad framebuffer height %u\n", r->height);
+		return -EINVAL;
+	}
+
+	if (r->flags & DRM_MODE_FB_LIVE_SOURCE)
+		return framebuffer_check_sources(dev, r);
+	else
+		return framebuffer_check_buffers(r, info->hsub, info->vsub);
+}
+
 struct drm_framebuffer *
 drm_internal_framebuffer_create(struct drm_device *dev,
 				const struct drm_mode_fb_cmd2 *r,
@@ -241,7 +318,8 @@ drm_internal_framebuffer_create(struct d
 	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_LIVE_SOURCE)) {
 		DRM_DEBUG_KMS("bad framebuffer flags 0x%08x\n", r->flags);
 		return ERR_PTR(-EINVAL);
 	}
@@ -263,7 +341,7 @@ drm_internal_framebuffer_create(struct d
 		return ERR_PTR(-EINVAL);
 	}
 
-	ret = framebuffer_check(r);
+	ret = framebuffer_check(dev, r);
 	if (ret)
 		return ERR_PTR(ret);
 
Index: linux/include/uapi/drm/drm_mode.h
===================================================================
--- linux.orig/include/uapi/drm/drm_mode.h
+++ linux/include/uapi/drm/drm_mode.h
@@ -405,6 +405,7 @@ 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_LIVE_SOURCE	(1<<2) /* connected to a live source */
 
 struct drm_mode_fb_cmd2 {
 	__u32 fb_id;
@@ -436,6 +437,12 @@ struct drm_mode_fb_cmd2 {
 	 * Thus all combinations of different data layouts for
 	 * multi plane formats must be enumerated as separate
 	 * modifiers.
+	 *
+	 * If the DRM_MODE_FB_LIVE_SOURCE flag is set the frame buffer input
+	 * comes from a live source instead of from memory. The handles[0]
+	 * field contains the ID of the connected live source object. All other
+	 * handles and all pitches, offsets and modifiers are then ignored by
+	 * the kernel and must be set to zero by applications.
 	 */
 	__u32 handles[4];
 	__u32 pitches[4]; /* pitch for each plane */