spl: Support loading a FIT from SPI

Detect a FIT when loading from SPI and handle it using the
new FIT SPL support.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>

drivers/mtd/spi/spi_spl_load.c

@@ -48,6 +48,18 @@ static int spi_load_image_os(struct spi_flash *flash,
 }
 #endif
 
+static ulong spl_spi_fit_read(struct spl_load_info *load, ulong sector,
+			      ulong count, void *buf)
+{
+	struct spi_flash *flash = load->dev;
+	ulong ret;
+
+	ret = spi_flash_read(flash, sector, count, buf);
+	if (!ret)
+		return count;
+	else
+		return 0;
+}
 /*
  * The main entry for SPI booting. It's necessary that SDRAM is already
  * configured and available since this code loads the main U-Boot image
@@ -85,11 +97,26 @@ int spl_spi_load_image(void)
 		if (err)
 			return err;
 
-		err = spl_parse_image_header(header);
-		if (err)
-			return err;
-		err = spi_flash_read(flash, CONFIG_SYS_SPI_U_BOOT_OFFS,
-			       spl_image.size, (void *)spl_image.load_addr);
+		if (IS_ENABLED(CONFIG_SPL_LOAD_FIT)) {
+			struct spl_load_info load;
+
+			debug("Found FIT\n");
+			load.dev = flash;
+			load.priv = NULL;
+			load.filename = NULL;
+			load.bl_len = 1;
+			load.read = spl_spi_fit_read;
+			err = spl_load_simple_fit(&load,
+						  CONFIG_SYS_SPI_U_BOOT_OFFS,
+						  header);
+		} else {
+			err = spl_parse_image_header(header);
+			if (err)
+				return err;
+			err = spi_flash_read(flash, CONFIG_SYS_SPI_U_BOOT_OFFS,
+					     spl_image.size,
+					     (void *)spl_image.load_addr);
+		}
 	}
 
 	return err;