drm/format-helper: Add conversion from XRGB8888 to ARGB8888

Add dedicated helper to convert from XRGB8888 to ARGB8888. Sets
all alpha bits to make pixels fully opaque.

v3:
	* use __le32 for destination buffer (Jose, kernel test robot)
v2:
	* use cpubuf_to_le32()
	* type fixes
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: José Expósito <jose.exposito89@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230102112927.26565-8-tzimmermann@suse.de

drivers/gpu/drm/drm_format_helper.c

@@ -446,6 +446,54 @@ void drm_fb_xrgb8888_to_rgb888(struct iosys_map *dst, const unsigned int *dst_pi
 }
 EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb888);
 
+static void drm_fb_xrgb8888_to_argb8888_line(void *dbuf, const void *sbuf, unsigned int pixels)
+{
+	__le32 *dbuf32 = dbuf;
+	const __le32 *sbuf32 = sbuf;
+	unsigned int x;
+	u32 pix;
+
+	for (x = 0; x < pixels; x++) {
+		pix = le32_to_cpu(sbuf32[x]);
+		pix |= GENMASK(31, 24); /* fill alpha bits */
+		dbuf32[x] = cpu_to_le32(pix);
+	}
+}
+
+/**
+ * drm_fb_xrgb8888_to_argb8888 - Convert XRGB8888 to ARGB8888 clip buffer
+ * @dst: Array of ARGB8888 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.
+ * @src: Array of XRGB8888 source buffer
+ * @fb: DRM framebuffer
+ * @clip: Clip rectangle area to copy
+ *
+ * This function copies parts of a framebuffer to display memory and converts the
+ * color format during the process. The parameters @dst, @dst_pitch and @src 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 ARGB8888 devices that don't support XRGB8888
+ * natively. It sets an opaque alpha channel as part of the conversion.
+ */
+void drm_fb_xrgb8888_to_argb8888(struct iosys_map *dst, const unsigned int *dst_pitch,
+				 const struct iosys_map *src, const struct drm_framebuffer *fb,
+				 const struct drm_rect *clip)
+{
+	static const u8 dst_pixsize[DRM_FORMAT_MAX_PLANES] = {
+		4,
+	};
+
+	drm_fb_xfrm(dst, dst_pitch, dst_pixsize, src, fb, clip, false,
+		    drm_fb_xrgb8888_to_argb8888_line);
+}
+EXPORT_SYMBOL(drm_fb_xrgb8888_to_argb8888);
+
 static void drm_fb_rgb565_to_xrgb8888_line(void *dbuf, const void *sbuf, unsigned int pixels)
 {
 	__le32 *dbuf32 = dbuf;
@@ -646,8 +694,6 @@ int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t d
 	/* treat alpha channel like filler bits */
 	if (fb_format == DRM_FORMAT_ARGB8888)
 		fb_format = DRM_FORMAT_XRGB8888;
-	if (dst_format == DRM_FORMAT_ARGB8888)
-		dst_format = DRM_FORMAT_XRGB8888;
 	if (fb_format == DRM_FORMAT_ARGB2101010)
 		fb_format = DRM_FORMAT_XRGB2101010;
 	if (dst_format == DRM_FORMAT_ARGB2101010)
@@ -669,6 +715,9 @@ int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t d
 		} else if (dst_format == DRM_FORMAT_RGB888) {
 			drm_fb_xrgb8888_to_rgb888(dst, dst_pitch, src, fb, clip);
 			return 0;
+		} else if (dst_format == DRM_FORMAT_ARGB8888) {
+			drm_fb_xrgb8888_to_argb8888(dst, dst_pitch, src, fb, clip);
+			return 0;
 		} else if (dst_format == DRM_FORMAT_XRGB2101010) {
 			drm_fb_xrgb8888_to_xrgb2101010(dst, dst_pitch, src, fb, clip);
 			return 0;

drivers/gpu/drm/tests/drm_format_helper_test.c

@@ -37,6 +37,11 @@ struct convert_to_rgb888_result {
 	const u8 expected[TEST_BUF_SIZE];
 };
 
+struct convert_to_argb8888_result {
+	unsigned int dst_pitch;
+	const u32 expected[TEST_BUF_SIZE];
+};
+
 struct convert_to_xrgb2101010_result {
 	unsigned int dst_pitch;
 	const u32 expected[TEST_BUF_SIZE];
@@ -51,6 +56,7 @@ struct convert_xrgb8888_case {
 	struct convert_to_rgb332_result rgb332_result;
 	struct convert_to_rgb565_result rgb565_result;
 	struct convert_to_rgb888_result rgb888_result;
+	struct convert_to_argb8888_result argb8888_result;
 	struct convert_to_xrgb2101010_result xrgb2101010_result;
 };
 
@@ -77,6 +83,10 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 			.dst_pitch = 0,
 			.expected = { 0x00, 0x00, 0xFF },
 		},
+		.argb8888_result = {
+			.dst_pitch = 0,
+			.expected = { 0xFFFF0000 },
+		},
 		.xrgb2101010_result = {
 			.dst_pitch = 0,
 			.expected = { 0x3FF00000 },
@@ -107,6 +117,10 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 			.dst_pitch = 0,
 			.expected = { 0x00, 0x00, 0xFF },
 		},
+		.argb8888_result = {
+			.dst_pitch = 0,
+			.expected = { 0xFFFF0000 },
+		},
 		.xrgb2101010_result = {
 			.dst_pitch = 0,
 			.expected = { 0x3FF00000 },
@@ -169,6 +183,15 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 				0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0x00,
 			},
 		},
+		.argb8888_result = {
+			.dst_pitch = 0,
+			.expected = {
+				0xFFFFFFFF, 0xFF000000,
+				0xFFFF0000, 0xFF00FF00,
+				0xFF0000FF, 0xFFFF00FF,
+				0xFFFFFF00, 0xFF00FFFF,
+			},
+		},
 		.xrgb2101010_result = {
 			.dst_pitch = 0,
 			.expected = {
@@ -229,6 +252,14 @@ static struct convert_xrgb8888_case convert_xrgb8888_cases[] = {
 				0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 			},
 		},
+		.argb8888_result = {
+			.dst_pitch = 20,
+			.expected = {
+				0xFF0E449C, 0xFF114D05, 0xFFA80303, 0x00000000, 0x00000000,
+				0xFF6C7073, 0xFF0E449C, 0xFF114D05, 0x00000000, 0x00000000,
+				0xFFA80303, 0xFF6C7073, 0xFF0E449C, 0x00000000, 0x00000000,
+			},
+		},
 		.xrgb2101010_result = {
 			.dst_pitch = 20,
 			.expected = {
@@ -448,6 +479,37 @@ static void drm_test_fb_xrgb8888_to_rgb888(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected, dst_size), 0);
 }
 
+static void drm_test_fb_xrgb8888_to_argb8888(struct kunit *test)
+{
+	const struct convert_xrgb8888_case *params = test->param_value;
+	const struct convert_to_argb8888_result *result = &params->argb8888_result;
+	size_t dst_size;
+	u32 *buf = NULL;
+	__le32 *xrgb8888 = NULL;
+	struct iosys_map dst, src;
+
+	struct drm_framebuffer fb = {
+		.format = drm_format_info(DRM_FORMAT_XRGB8888),
+		.pitches = { params->pitch, 0, 0 },
+	};
+
+	dst_size = conversion_buf_size(DRM_FORMAT_ARGB8888,
+				       result->dst_pitch, &params->clip);
+	KUNIT_ASSERT_GT(test, dst_size, 0);
+
+	buf = kunit_kzalloc(test, dst_size, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);
+	iosys_map_set_vaddr(&dst, buf);
+
+	xrgb8888 = cpubuf_to_le32(test, params->xrgb8888, TEST_BUF_SIZE);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, xrgb8888);
+	iosys_map_set_vaddr(&src, xrgb8888);
+
+	drm_fb_xrgb8888_to_argb8888(&dst, &result->dst_pitch, &src, &fb, &params->clip);
+	buf = le32buf_to_cpu(test, (__force const __le32 *)buf, dst_size / sizeof(u32));
+	KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected, dst_size), 0);
+}
+
 static void drm_test_fb_xrgb8888_to_xrgb2101010(struct kunit *test)
 {
 	const struct convert_xrgb8888_case *params = test->param_value;
@@ -484,6 +546,7 @@ static struct kunit_case drm_format_helper_test_cases[] = {
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_rgb332, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_rgb565, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_rgb888, convert_xrgb8888_gen_params),
+	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_argb8888, convert_xrgb8888_gen_params),
 	KUNIT_CASE_PARAM(drm_test_fb_xrgb8888_to_xrgb2101010, convert_xrgb8888_gen_params),
 	{}
 };

include/drm/drm_format_helper.h

@@ -33,6 +33,9 @@ void drm_fb_xrgb8888_to_rgb565(struct iosys_map *dst, const unsigned int *dst_pi
 void drm_fb_xrgb8888_to_rgb888(struct iosys_map *dst, const unsigned int *dst_pitch,
 			       const struct iosys_map *src, const struct drm_framebuffer *fb,
 			       const struct drm_rect *clip);
+void drm_fb_xrgb8888_to_argb8888(struct iosys_map *dst, const unsigned int *dst_pitch,
+				 const struct iosys_map *src, const struct drm_framebuffer *fb,
+				 const struct drm_rect *clip);
 void drm_fb_xrgb8888_to_xrgb2101010(struct iosys_map *dst, const unsigned int *dst_pitch,
 				    const struct iosys_map *src, const struct drm_framebuffer *fb,
 				    const struct drm_rect *clip);