drm/exynos: check NV12M format specific to Exynos properly

this patch adds buf_cnt variable in exynos_drm_fb structure and
that means a buffer count to drm framebuffer and also adds two
functions to get/set the buffer count from/to exynos_drm_fb structure.
if pixel format is not DRM_FORMAT_NV12MT then it gets a buffer count
to drm framebuffer refering to mode_cmd->handles and offsets.
but when booted, the buffer count will always be 1 because pixel
format of console framebuffer is RGB format.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_fb.c

@@ -41,10 +41,12 @@
  * exynos specific framebuffer structure.
  *
  * @fb: drm framebuffer obejct.
+ * @buf_cnt: a buffer count to drm framebuffer.
  * @exynos_gem_obj: array of exynos specific gem object containing a gem object.
  */
 struct exynos_drm_fb {
 	struct drm_framebuffer		fb;
+	unsigned int			buf_cnt;
 	struct exynos_drm_gem_obj	*exynos_gem_obj[MAX_FB_BUFFER];
 };
 
@@ -101,6 +103,25 @@ static struct drm_framebuffer_funcs exynos_drm_fb_funcs = {
 	.dirty		= exynos_drm_fb_dirty,
 };
 
+void exynos_drm_fb_set_buf_cnt(struct drm_framebuffer *fb,
+						unsigned int cnt)
+{
+	struct exynos_drm_fb *exynos_fb;
+
+	exynos_fb = to_exynos_fb(fb);
+
+	exynos_fb->buf_cnt = cnt;
+}
+
+unsigned int exynos_drm_fb_get_buf_cnt(struct drm_framebuffer *fb)
+{
+	struct exynos_drm_fb *exynos_fb;
+
+	exynos_fb = to_exynos_fb(fb);
+
+	return exynos_fb->buf_cnt;
+}
+
 struct drm_framebuffer *
 exynos_drm_framebuffer_init(struct drm_device *dev,
 			    struct drm_mode_fb_cmd2 *mode_cmd,
@@ -127,14 +148,50 @@ exynos_drm_framebuffer_init(struct drm_device *dev,
 	return &exynos_fb->fb;
 }
 
+static u32 exynos_drm_format_num_buffers(struct drm_mode_fb_cmd2 *mode_cmd)
+{
+	unsigned int cnt = 0;
+
+	if (mode_cmd->pixel_format != DRM_FORMAT_NV12)
+		return drm_format_num_planes(mode_cmd->pixel_format);
+
+	while (cnt != MAX_FB_BUFFER) {
+		if (!mode_cmd->handles[cnt])
+			break;
+		cnt++;
+	}
+
+	/*
+	 * check if NV12 or NV12M.
+	 *
+	 * NV12
+	 * handles[0] = base1, offsets[0] = 0
+	 * handles[1] = base1, offsets[1] = Y_size
+	 *
+	 * NV12M
+	 * handles[0] = base1, offsets[0] = 0
+	 * handles[1] = base2, offsets[1] = 0
+	 */
+	if (cnt == 2) {
+		/*
+		 * in case of NV12 format, offsets[1] is not 0 and
+		 * handles[0] is same as handles[1].
+		 */
+		if (mode_cmd->offsets[1] &&
+			mode_cmd->handles[0] == mode_cmd->handles[1])
+			cnt = 1;
+	}
+
+	return cnt;
+}
+
 static struct drm_framebuffer *
 exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 		      struct drm_mode_fb_cmd2 *mode_cmd)
 {
 	struct drm_gem_object *obj;
 	struct drm_framebuffer *fb;
 	struct exynos_drm_fb *exynos_fb;
-	int nr;
 	int i;
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
@@ -152,9 +209,11 @@ exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 	}
 
 	exynos_fb = to_exynos_fb(fb);
-	nr = exynos_drm_format_num_buffers(fb->pixel_format);
+	exynos_fb->buf_cnt = exynos_drm_format_num_buffers(mode_cmd);
+
+	DRM_DEBUG_KMS("buf_cnt = %d\n", exynos_fb->buf_cnt);
 
-	for (i = 1; i < nr; i++) {
+	for (i = 1; i < exynos_fb->buf_cnt; i++) {
 		obj = drm_gem_object_lookup(dev, file_priv,
 				mode_cmd->handles[i]);
 		if (!obj) {

drivers/gpu/drm/exynos/exynos_drm_fb.h

@@ -28,19 +28,6 @@
 #ifndef _EXYNOS_DRM_FB_H_
 #define _EXYNOS_DRM_FB_H
 
-static inline int exynos_drm_format_num_buffers(uint32_t format)
-{
-	switch (format) {
-	case DRM_FORMAT_NV12:
-	case DRM_FORMAT_NV12MT:
-		return 2;
-	case DRM_FORMAT_YUV420:
-		return 3;
-	default:
-		return 1;
-	}
-}
-
 struct drm_framebuffer *
 exynos_drm_framebuffer_init(struct drm_device *dev,
 			    struct drm_mode_fb_cmd2 *mode_cmd,
@@ -52,4 +39,11 @@ struct exynos_drm_gem_buf *exynos_drm_fb_buffer(struct drm_framebuffer *fb,
 
 void exynos_drm_mode_config_init(struct drm_device *dev);
 
+/* set a buffer count to drm framebuffer. */
+void exynos_drm_fb_set_buf_cnt(struct drm_framebuffer *fb,
+						unsigned int cnt);
+
+/* get a buffer count to drm framebuffer. */
+unsigned int exynos_drm_fb_get_buf_cnt(struct drm_framebuffer *fb);
+
 #endif

drivers/gpu/drm/exynos/exynos_drm_fbdev.c

@@ -79,6 +79,9 @@ static int exynos_drm_fbdev_update(struct drm_fb_helper *helper,
 		return -EFAULT;
 	}
 
+	/* buffer count to framebuffer always is 1 at booting time. */
+	exynos_drm_fb_set_buf_cnt(fb, 1);
+
 	offset = fbi->var.xoffset * (fb->bits_per_pixel >> 3);
 	offset += fbi->var.yoffset * fb->pitches[0];
 

drivers/gpu/drm/exynos/exynos_drm_plane.c

@@ -47,7 +47,7 @@ int exynos_plane_mode_set(struct drm_plane *plane, struct drm_crtc *crtc,
 
 	DRM_DEBUG_KMS("[%d] %s\n", __LINE__, __func__);
 
-	nr = exynos_drm_format_num_buffers(fb->pixel_format);
+	nr = exynos_drm_fb_get_buf_cnt(fb);
 	for (i = 0; i < nr; i++) {
 		struct exynos_drm_gem_buf *buffer = exynos_drm_fb_buffer(fb, i);