lib: Rename fill_lb_framebuffer to get_lb_framebuffer

Rename `fill_lb_framebuffer` to `get_lb_framebuffer` to better
reflect that it returns framebuffer information.

The new `get_lb_framebuffer` returns a constant pointer to the
framebuffer structure instead of filling a provided structure.
This simplifies the API and avoids an unnecessary memory copy.

The file `edid_fill_fb.c` is renamed to `framebuffer_info.c`
to better match the function it now contains.

Call sites in `coreboot_table.c` and `render_bmp.c` are
updated to use the new API.

TEST=emerge-tanjiro coreboot; check the FW logo is correctly drawn.
BUG=b:319511268

Change-Id: I8d7b20a0524b6bc9fff9e6461fa0c253345df790
Signed-off-by: Yidi Lin <yidilin@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/90725
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Chen-Tsung Hsieh <chentsung@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/include/boot/coreboot_tables.h

@@ -33,9 +33,9 @@ void lb_efi_fw_info(struct lb_header *header);
 /* Adds LB_TAG_CAPSULE table entries. */
 void lb_efi_capsules(struct lb_header *header);
 
-/* Define this function to fill in the frame buffer returning 0 on success and
-   < 0 on error. */
-int fill_lb_framebuffer(struct lb_framebuffer *framebuffer);
+/* Define this function to get the frame buffer returning lb_framebuffer object
+   on success and NULL on error. */
+const struct lb_framebuffer *get_lb_framebuffer(void);
 
 /* Allow arch to add records. */
 void lb_arch_add_records(struct lb_header *header);

src/lib/Makefile.mk

@@ -154,8 +154,8 @@ ramstage-$(CONFIG_BOOTSPLASH) += jpeg.c
 ramstage-$(CONFIG_COLLECT_TIMESTAMPS) += timestamp.c
 ramstage-$(CONFIG_COVERAGE) += libgcov.c
 ramstage-y += dp_aux.c
+ramstage-y += framebuffer_info.c
 ramstage-y += edid.c
-ramstage-y += edid_fill_fb.c
 ramstage-y += memrange.c
 ramstage-$(CONFIG_GENERIC_GPIO_LIB) += gpio.c
 ramstage-$(CONFIG_GENERIC_UDELAY) += timer.c

src/lib/coreboot_table.c

@@ -142,13 +142,13 @@ static void lb_pcie(struct lb_header *header)
 static void lb_framebuffer(struct lb_header *header)
 {
 	struct lb_framebuffer *framebuffer;
-	struct lb_framebuffer fb = {0};
+	const struct lb_framebuffer *fb;
 
-	if (!CONFIG(LINEAR_FRAMEBUFFER) || fill_lb_framebuffer(&fb))
+	if (!CONFIG(LINEAR_FRAMEBUFFER) || !(fb = get_lb_framebuffer()))
 		return;
 
 	framebuffer = (struct lb_framebuffer *)lb_new_record(header);
-	memcpy(framebuffer, &fb, sizeof(*framebuffer));
+	memcpy(framebuffer, fb, sizeof(*framebuffer));
 	framebuffer->tag = LB_TAG_FRAMEBUFFER;
 	framebuffer->size = sizeof(*framebuffer);
 

src/lib/framebuffer_info.c

@@ -181,14 +181,13 @@ struct fb_info *fb_new_framebuffer_info_from_edid(const struct edid *edid,
 		edid->bytes_per_line, edid->framebuffer_bits_per_pixel);
 }
 
-int fill_lb_framebuffer(struct lb_framebuffer *framebuffer)
+const struct lb_framebuffer *get_lb_framebuffer(void)
 {
 	struct fb_info *i;
 
 	list_for_each(i, list, node) {
 		//TODO: Add support for advertising all framebuffers in this list
-		*framebuffer = i->fb;
-		return 0;
+		return &i->fb;
 	}
-	return -1;
+	return NULL;
 }

src/lib/render_bmp.c

@@ -689,16 +689,14 @@ void render_logo_to_framebuffer(struct logo_config *config)
 
 	if (config->framebuffer_base == 0) {
 		/* Try to load from already populated framebuffer information */
-		struct lb_framebuffer framebuffer;
-		memset(&framebuffer, 0, sizeof(struct lb_framebuffer));
-		fill_lb_framebuffer(&framebuffer);
+		const struct lb_framebuffer *fb = get_lb_framebuffer();
 		/* Exit if framebuffer is still not available */
-		if (framebuffer.physical_address == 0)
+		if (!fb)
 			return;
-		config->framebuffer_base = framebuffer.physical_address;
-		config->horizontal_resolution = framebuffer.x_resolution;
-		config->vertical_resolution = framebuffer.y_resolution;
-		config->bytes_per_scanline = framebuffer.bytes_per_line;
+		config->framebuffer_base = fb->physical_address;
+		config->horizontal_resolution = fb->x_resolution;
+		config->vertical_resolution = fb->y_resolution;
+		config->bytes_per_scanline = fb->bytes_per_line;
 	}
 
 	/*