drm/format-helper: Rework XRGB8888-to-GRAY8 conversion

Update XRGB8888-to-GRAY8 conversion to support struct iosys_map
and convert all users. Although these are single-plane color formats,
the new interface supports multi-plane formats for consistency with
drm_fb_blit().

v2:
	* update documentation (Sam)
	* add TODO on vaddr location (Sam)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220808125406.20752-12-tzimmermann@suse.de

1 files changed, 34 insertions, 12 deletions

diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index 795d845c7e53..890370c0424f 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -613,25 +613,47 @@ static void drm_fb_xrgb8888_to_gray8_line(void *dbuf, const void *sbuf, unsigned
 
 /**
  * drm_fb_xrgb8888_to_gray8 - Convert XRGB8888 to grayscale
- * @dst: 8-bit grayscale destination buffer
- * @dst_pitch: Number of bytes between two consecutive scanlines within dst
- * @vaddr: XRGB8888 source buffer
+ * @dst: Array of 8-bit grayscale destination buffers
+ * @dst_pitch: Array of numbers of bytes between the start of two consecutive scanlines
+ *             within @dst; can be NULL if scanlines are stored next to each other.
+ * @vmap: Array of XRGB8888 source buffers
  * @fb: DRM framebuffer
  * @clip: Clip rectangle area to copy
  *
- * Drm doesn't have native monochrome or grayscale support.
- * Such drivers can announce the commonly supported XR24 format to userspace
- * and use this function to convert to the native format.
+ * This function copies parts of a framebuffer to display memory and converts the
+ * color format during the process. Destination and framebuffer formats must match. The
+ * parameters @dst, @dst_pitch and @vmap refer to arrays. Each array must have at
+ * least as many entries as there are planes in @fb's format. Each entry stores the
+ * value for the format's respective color plane at the same index.
  *
- * Monochrome drivers will use the most significant bit,
- * where 1 means foreground color and 0 background color.
+ * This function does not apply clipping on @dst (i.e. the destination is at the
+ * top-left corner).
  *
- * ITU BT.601 is used for the RGB -> luma (brightness) conversion.
+ * DRM doesn't have native monochrome or grayscale support. Drivers can use this
+ * function for grayscale devices that don't support XRGB8888 natively.Such
+ * drivers can announce the commonly supported XR24 format to userspace and use
+ * this function to convert to the native format. Monochrome drivers will use the
+ * most significant bit, where 1 means foreground color and 0 background color.
+ * ITU BT.601 is being used for the RGB -> luma (brightness) conversion.
  */
-void drm_fb_xrgb8888_to_gray8(void *dst, unsigned int dst_pitch, const void *vaddr,
-			      const struct drm_framebuffer *fb, const struct drm_rect *clip)
+void drm_fb_xrgb8888_to_gray8(struct iosys_map *dst, const unsigned int *dst_pitch,
+			      const struct iosys_map *vmap, const struct drm_framebuffer *fb,
+			      const struct drm_rect *clip)
 {
-	drm_fb_xfrm(dst, dst_pitch, 1, vaddr, fb, clip, false, drm_fb_xrgb8888_to_gray8_line);
+	static const unsigned int default_dst_pitch[DRM_FORMAT_MAX_PLANES] = {
+		0, 0, 0, 0
+	};
+
+	if (!dst_pitch)
+		dst_pitch = default_dst_pitch;
+
+	/* TODO: handle vmap in I/O memory here */
+	if (dst[0].is_iomem)
+		drm_fb_xfrm_toio(dst[0].vaddr_iomem, dst_pitch[0], 1, vmap[0].vaddr, fb,
+				 clip, false, drm_fb_xrgb8888_to_gray8_line);
+	else
+		drm_fb_xfrm(dst[0].vaddr, dst_pitch[0], 1, vmap[0].vaddr, fb,
+			    clip, false, drm_fb_xrgb8888_to_gray8_line);
 }
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_gray8);