{lib, drivers/intel}: Add splash screen footer

This commit introduces the `SPLASH_SCREEN_FOOTER` Kconfig option,
enabling a custom footer image or logo on the firmware splash screen.
This provides an additional branding opportunity for device
manufacturers.

`soc_load_logo_by_coreboot()` now conditionally loads and renders
`footer_logo.bmp` when this option is enabled. The footer logo is
positioned at the bottom of the screen.

A new `SPLASH_SCREEN_FOOTER_LOGO_PATH` Kconfig option is added to
define the footer logo's file path. It defaults to a mainboard-specific
location. `Makefile.mk` is updated to ensure this logo is included in
the CBFS.

This additional branding is made possible by rendering bitmaps using
coreboot's native implementation (`USE_COREBOOT_FOR_BMP_RENDERING`).
FSP currently lacks the necessary callbacks to support this feature.

Currently, the OEM footer branding will appear even when the
system is booting in low-battery mode. A planned update will fix this
by exiting early from the boot process, preventing the footer from
showing and conserving power.

BUG=b:423591644
TEST=Able to display custom footer logo on boot.

Change-Id: I57f8af910e8b8f56e8a4a88f8cca6d60fad380b6
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88029
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>

src/drivers/intel/fsp2_0/cb_logo.c

@@ -179,6 +179,27 @@ void soc_load_logo_by_coreboot(void)
 	copy_logo_to_framebuffer(framebuffer_bar, bytes_per_scanline, blt_buffer_addr, logo_width,
 			 logo_height, logo_coords.x, logo_coords.y);
 
+	if (CONFIG(SPLASH_SCREEN_FOOTER)) {
+		bmp_release_logo();
+		logo_ptr = (uintptr_t)bmp_load_logo_by_type(BOOTSPLASH_FOOTER, &logo_ptr_size);
+		if (!logo_ptr || logo_ptr_size < sizeof(efi_bmp_image_header)) {
+			printk(BIOS_ERR, "%s: BMP image (%zu) is less than expected minimum size (%zu).\n",
+				 __func__, logo_ptr_size, sizeof(efi_bmp_image_header));
+			return;
+		}
+
+		/* Convert BMP logo to GOP BLT format */
+		fsp_convert_bmp_to_gop_blt(logo_ptr, logo_ptr_size, &blt_buffer_addr, &blt_size,
+				   &logo_height, &logo_width, config->panel_orientation);
+
+		logo_coords = calculate_logo_coordinates(horizontal_resolution,
+				 vertical_resolution, logo_width, logo_height, FW_SPLASH_VALIGNMENT_BOTTOM);
+
+		/* Copy the logo to the framebuffer */
+		copy_logo_to_framebuffer(framebuffer_bar, bytes_per_scanline, blt_buffer_addr,
+				 logo_width, logo_height, logo_coords.x, logo_coords.y);
+	}
+
 	/* Clear temporary Write Combine (WC) MTRR */
 	clear_var_mtrr(temp_mtrr_index);
 }

src/include/bootsplash.h

@@ -10,6 +10,8 @@ enum bootsplash_type {
 	BOOTSPLASH_LOW_BATTERY,
 	/* Indicates a Main OEM defined bootsplash logo for center of the splash screen. */
 	BOOTSPLASH_CENTER,
+	/* Indicates an optional OEM defined bootsplash logo for footer of the splash screen. */
+	BOOTSPLASH_FOOTER,
 
 	/* It's used to determine the total number of bootsplash types. */
 	BOOTSPLASH_MAX_NUM,

src/lib/Kconfig

@@ -254,6 +254,21 @@ config PLATFORM_LOW_BATTERY_INDICATOR_LOGO_PATH
 	default "3rdparty/blobs/mainboard/\$(MAINBOARDDIR)/low_battery.bmp"
 endif
 
+config SPLASH_SCREEN_FOOTER
+	bool "Enable custom footer on firmware splash screen"
+	depends on BMP_LOGO
+	help
+	  Enable this option to display a custom footer image or logo on the
+	  firmware splash screen during the boot process. This provides an
+	  additional branding opportunity for device manufacturers, allowing
+	  them to display a logo or other graphic at the bottom of the
+	  splash screen, complementing the main OEM splash image.
+
+config SPLASH_SCREEN_FOOTER_LOGO_PATH
+	string "Path to splash screen footer logo file"
+	depends on SPLASH_SCREEN_FOOTER
+	default "3rdparty/blobs/mainboard/\$(MAINBOARDDIR)/logo.bmp"
+
 endmenu
 
 config HAVE_EARLY_POWEROFF_SUPPORT

src/lib/Makefile.mk

@@ -447,3 +447,5 @@ endif
 
 $(eval $(call add_bmp_logo_file_to_cbfs,CONFIG_PLATFORM_HAS_LOW_BATTERY_INDICATOR, \
 	      low_battery.bmp,CONFIG_PLATFORM_LOW_BATTERY_INDICATOR_LOGO_PATH))
+$(eval $(call add_bmp_logo_file_to_cbfs,CONFIG_SPLASH_SCREEN_FOOTER, \
+	      footer_logo.bmp,CONFIG_SPLASH_SCREEN_FOOTER_LOGO_PATH))

src/lib/bmp_logo.c

@@ -12,7 +12,8 @@ static const struct cbmem_entry *logo_entry;
 /* Mapping of different bootsplash logo name based on bootsplash type */
 static const char *bootsplash_list[BOOTSPLASH_MAX_NUM] = {
 	[BOOTSPLASH_LOW_BATTERY] = "low_battery.bmp",
-	[BOOTSPLASH_CENTER] = "logo.bmp"
+	[BOOTSPLASH_CENTER] = "logo.bmp",
+	[BOOTSPLASH_FOOTER] = "footer_logo.bmp"
 };
 
 /*