drm/format-helper: Rework XRGB8888-to-RGBG332 conversion

Update XRGB8888-to-RGB332 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:
	* rebase onto refactored Kunit tests
	* 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/20220808125406.20752-6-tzimmermann@suse.de

drivers/gpu/drm/drm_format_helper.c

@@ -281,18 +281,42 @@ static void drm_fb_xrgb8888_to_rgb332_line(void *dbuf, const void *sbuf, unsigne
 
 /**
  * drm_fb_xrgb8888_to_rgb332 - Convert XRGB8888 to RGB332 clip buffer
- * @dst: RGB332 destination buffer
- * @dst_pitch: Number of bytes between two consecutive scanlines within dst
- * @src: XRGB8888 source buffer
+ * @dst: Array of RGB332 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
  *
- * Drivers can use this function for RGB332 devices that don't natively support XRGB8888.
+ * 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.
+ *
+ * This function does not apply clipping on @dst (i.e. the destination is at the
+ * top-left corner).
+ *
+ * Drivers can use this function for RGB332 devices that don't support XRGB8888 natively.
  */
-void drm_fb_xrgb8888_to_rgb332(void *dst, unsigned int dst_pitch, const void *src,
-			       const struct drm_framebuffer *fb, const struct drm_rect *clip)
+void drm_fb_xrgb8888_to_rgb332(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, src, fb, clip, false, drm_fb_xrgb8888_to_rgb332_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_rgb332_line);
+	else
+		drm_fb_xfrm(dst[0].vaddr, dst_pitch[0], 1, vmap[0].vaddr, fb, clip,
+			    false, drm_fb_xrgb8888_to_rgb332_line);
 }
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb332);
 

drivers/gpu/drm/gud/gud_pipe.c

@@ -196,7 +196,7 @@ static int gud_prep_flush(struct gud_device *gdrm, struct drm_framebuffer *fb,
 		} else if (format->format == DRM_FORMAT_R8) {
 			drm_fb_xrgb8888_to_gray8(buf, 0, vaddr, fb, rect);
 		} else if (format->format == DRM_FORMAT_RGB332) {
-			drm_fb_xrgb8888_to_rgb332(buf, 0, vaddr, fb, rect);
+			drm_fb_xrgb8888_to_rgb332(&dst, NULL, map_data, fb, rect);
 		} else if (format->format == DRM_FORMAT_RGB565) {
 			drm_fb_xrgb8888_to_rgb565(buf, 0, vaddr, fb, rect, gud_is_big_endian());
 		} else if (format->format == DRM_FORMAT_RGB888) {

drivers/gpu/drm/tests/drm_format_helper_test.c

@@ -197,8 +197,9 @@ static void xrgb8888_to_rgb332_test(struct kunit *test)
 	const struct convert_xrgb8888_case *params = test->param_value;
 	const struct convert_to_rgb332_result *result = &params->rgb332_result;
 	size_t dst_size;
-	__u8 *dst = NULL;
-	__u32 *src = NULL;
+	__u8 *buf = NULL;
+	__u32 *xrgb8888 = NULL;
+	struct iosys_map dst, src;
 
 	struct drm_framebuffer fb = {
 		.format = drm_format_info(DRM_FORMAT_XRGB8888),
@@ -209,15 +210,16 @@ static void xrgb8888_to_rgb332_test(struct kunit *test)
 				       &params->clip);
 	KUNIT_ASSERT_GT(test, dst_size, 0);
 
-	dst = kunit_kzalloc(test, dst_size, GFP_KERNEL);
-	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dst);
+	buf = kunit_kzalloc(test, dst_size, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);
+	iosys_map_set_vaddr(&dst, buf);
 
-	src = le32buf_to_cpu(test, params->xrgb8888, TEST_BUF_SIZE);
-	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, src);
+	xrgb8888 = le32buf_to_cpu(test, params->xrgb8888, TEST_BUF_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, xrgb8888);
+	iosys_map_set_vaddr(&src, xrgb8888);
 
-	drm_fb_xrgb8888_to_rgb332(dst, result->dst_pitch, src, &fb,
-				  &params->clip);
-	KUNIT_EXPECT_EQ(test, memcmp(dst, result->expected, dst_size), 0);
+	drm_fb_xrgb8888_to_rgb332(&dst, &result->dst_pitch, &src, &fb, &params->clip);
+	KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected, dst_size), 0);
 }
 
 static void xrgb8888_to_rgb565_test(struct kunit *test)

include/drm/drm_format_helper.h

@@ -20,8 +20,9 @@ void drm_fb_memcpy(struct iosys_map *dst, const unsigned int *dst_pitch,
 void drm_fb_swab(struct iosys_map *dst, const unsigned int *dst_pitch,
 		 const struct iosys_map *vmap, const struct drm_framebuffer *fb,
 		 const struct drm_rect *clip, bool cached);
-void drm_fb_xrgb8888_to_rgb332(void *dst, unsigned int dst_pitch, const void *vaddr,
-			       const struct drm_framebuffer *fb, const struct drm_rect *clip);
+void drm_fb_xrgb8888_to_rgb332(struct iosys_map *dst, const unsigned int *dst_pitch,
+			       const struct iosys_map *vmap, const struct drm_framebuffer *fb,
+			       const struct drm_rect *clip);
 void drm_fb_xrgb8888_to_rgb565(void *dst, unsigned int dst_pitch, const void *vaddr,
 			       const struct drm_framebuffer *fb, const struct drm_rect *clip,
 			       bool swab);