drm/format-helper: Provide drm_fb_blit()

Provide drm_fb_blit() that works with struct iosys_map. Update all
users of drm_fb_blit_toio(), which required a destination buffer in
I/O memory.

This patch only updates the function's interface. The implementation
still relies on the destination buffer to be located in  I/O memory.
See the follow-up patches for implementational changes. The new
function's interface works with multi-plane color formats, but again
implementation only supports a single plane for now.

v2:
	* rebase onto refactored simpledrm
	* use IOSYS_MAP_INIT_VADDR() (Sam)
	* update the commit message on the use of I/O memory (Sam)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220808125406.20752-3-tzimmermann@suse.de

drivers/gpu/drm/drm_format_helper.c

@@ -8,9 +8,10 @@
  * (at your option) any later version.
  */
 
+#include <linux/io.h>
+#include <linux/iosys-map.h>
 #include <linux/module.h>
 #include <linux/slab.h>
-#include <linux/io.h>
 
 #include <drm/drm_device.h>
 #include <drm/drm_format_helper.h>
@@ -545,9 +546,10 @@ void drm_fb_xrgb8888_to_gray8(void *dst, unsigned int dst_pitch, const void *vad
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_gray8);
 
 /**
- * drm_fb_blit_toio - Copy parts of a framebuffer to display memory
- * @dst:	The display memory to copy to
- * @dst_pitch:	Number of bytes between two consecutive scanlines within dst
+ * drm_fb_blit - Copy parts of a framebuffer to display memory
+ * @dst:	Array of display-memory addresses to copy to
+ * @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.
  * @dst_format:	FOURCC code of the display's color format
  * @vmap:	The framebuffer memory to copy from
  * @fb:		The framebuffer to copy from
@@ -555,15 +557,21 @@ EXPORT_SYMBOL(drm_fb_xrgb8888_to_gray8);
  *
  * This function copies parts of a framebuffer to display memory. If the
  * formats of the display and the framebuffer mismatch, the blit function
- * will attempt to convert between them.
+ * will attempt to convert between them during the process. The parameters @dst,
+ * @dst_pitch and @vmap refer to arrays. Each array must have at least as many
+ * entries as there are planes in @dst_format's format. Each entry stores the
+ * value for the format's respective color plane at the same index.
+ *
+ * This function does not apply clipping on @dst (i.e. the destination is at the
+ * top-left corner).
  *
  * Returns:
  * 0 on success, or
  * -EINVAL if the color-format conversion failed, or
  * a negative error code otherwise.
  */
-int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_format,
-		     const void *vmap, const struct drm_framebuffer *fb,
+int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t dst_format,
+		const struct iosys_map *vmap, const struct drm_framebuffer *fb,
 		const struct drm_rect *clip)
 {
 	uint32_t fb_format = fb->format->format;
@@ -579,30 +587,35 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for
 		dst_format = DRM_FORMAT_XRGB2101010;
 
 	if (dst_format == fb_format) {
-		drm_fb_memcpy_toio(dst, dst_pitch, vmap, fb, clip);
+		drm_fb_memcpy_toio(dst[0].vaddr_iomem, dst_pitch[0], vmap[0].vaddr, fb, clip);
 		return 0;
 
 	} else if (dst_format == DRM_FORMAT_RGB565) {
 		if (fb_format == DRM_FORMAT_XRGB8888) {
-			drm_fb_xrgb8888_to_rgb565_toio(dst, dst_pitch, vmap, fb, clip, false);
+			drm_fb_xrgb8888_to_rgb565_toio(dst[0].vaddr_iomem, dst_pitch[0],
+						       vmap[0].vaddr, fb, clip, false);
 			return 0;
 		}
 	} else if (dst_format == DRM_FORMAT_RGB888) {
 		if (fb_format == DRM_FORMAT_XRGB8888) {
-			drm_fb_xrgb8888_to_rgb888_toio(dst, dst_pitch, vmap, fb, clip);
+			drm_fb_xrgb8888_to_rgb888_toio(dst[0].vaddr_iomem, dst_pitch[0],
+						       vmap[0].vaddr, fb, clip);
 			return 0;
 		}
 	} else if (dst_format == DRM_FORMAT_XRGB8888) {
 		if (fb_format == DRM_FORMAT_RGB888) {
-			drm_fb_rgb888_to_xrgb8888_toio(dst, dst_pitch, vmap, fb, clip);
+			drm_fb_rgb888_to_xrgb8888_toio(dst[0].vaddr_iomem, dst_pitch[0],
+						       vmap[0].vaddr, fb, clip);
 			return 0;
 		} else if (fb_format == DRM_FORMAT_RGB565) {
-			drm_fb_rgb565_to_xrgb8888_toio(dst, dst_pitch, vmap, fb, clip);
+			drm_fb_rgb565_to_xrgb8888_toio(dst[0].vaddr_iomem, dst_pitch[0],
+						       vmap[0].vaddr, fb, clip);
 			return 0;
 		}
 	} else if (dst_format == DRM_FORMAT_XRGB2101010) {
 		if (fb_format == DRM_FORMAT_XRGB8888) {
-			drm_fb_xrgb8888_to_xrgb2101010_toio(dst, dst_pitch, vmap, fb, clip);
+			drm_fb_xrgb8888_to_xrgb2101010_toio(dst[0].vaddr_iomem, dst_pitch[0],
+							    vmap[0].vaddr, fb, clip);
 			return 0;
 		}
 	}
@@ -612,8 +625,7 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for
 
 	return -EINVAL;
 }
-EXPORT_SYMBOL(drm_fb_blit_toio);
-
+EXPORT_SYMBOL(drm_fb_blit);
 
 static void drm_fb_gray8_to_mono_line(void *dbuf, const void *sbuf, unsigned int pixels)
 {

drivers/gpu/drm/tiny/simpledrm.c

@@ -508,11 +508,10 @@ static void simpledrm_primary_plane_helper_atomic_update(struct drm_plane *plane
 	struct drm_plane_state *plane_state = plane->state;
 	struct drm_plane_state *old_plane_state = drm_atomic_get_old_plane_state(old_state, plane);
 	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
-	void *vmap = shadow_plane_state->data[0].vaddr; /* TODO: Use mapping abstraction */
 	struct drm_framebuffer *fb = plane_state->fb;
 	struct drm_device *dev = plane->dev;
 	struct simpledrm_device *sdev = simpledrm_device_of_dev(dev);
-	void __iomem *dst = sdev->screen_base;
+	struct iosys_map dst = IOSYS_MAP_INIT_VADDR(sdev->screen_base);
 	struct drm_rect src_clip, dst_clip;
 	int idx;
 
@@ -529,8 +528,9 @@ static void simpledrm_primary_plane_helper_atomic_update(struct drm_plane *plane
 	if (!drm_dev_enter(dev, &idx))
 		return;
 
-	dst += drm_fb_clip_offset(sdev->pitch, sdev->format, &dst_clip);
-	drm_fb_blit_toio(dst, sdev->pitch, sdev->format->format, vmap, fb, &src_clip);
+	iosys_map_incr(&dst, drm_fb_clip_offset(sdev->pitch, sdev->format, &dst_clip));
+	drm_fb_blit(&dst, &sdev->pitch, sdev->format->format, shadow_plane_state->data, fb,
+		    &src_clip);
 
 	drm_dev_exit(idx);
 }

include/drm/drm_format_helper.h

@@ -6,6 +6,7 @@
 #ifndef __LINUX_DRM_FORMAT_HELPER_H
 #define __LINUX_DRM_FORMAT_HELPER_H
 
+struct iosys_map;
 struct drm_format_info;
 struct drm_framebuffer;
 struct drm_rect;
@@ -39,8 +40,8 @@ void drm_fb_xrgb8888_to_xrgb2101010_toio(void __iomem *dst, unsigned int dst_pit
 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);
 
-int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_format,
-		     const void *vmap, const struct drm_framebuffer *fb,
+int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t dst_format,
+		const struct iosys_map *vmap, const struct drm_framebuffer *fb,
 		const struct drm_rect *rect);
 
 void drm_fb_xrgb8888_to_mono(void *dst, unsigned int dst_pitch, const void *src,