SPL: SPI: sunxi: add SPL FIT image support

The sunxi-specific SPI load routine only knows how to load a legacy
U-Boot image.
Teach it how to handle FIT images as well, simply by providing the
existing SPL FIT loader with the right loader routine to access the SPI
NOR flash.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reported-by: Peter Kosa <kope@madnet.sk>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>

drivers/mtd/spi/sunxi_spi_spl.c

@@ -8,6 +8,7 @@
 #include <spl.h>
 #include <asm/gpio.h>
 #include <asm/io.h>
+#include <libfdt.h>
 
 #ifdef CONFIG_SPL_OS_BOOT
 #error CONFIG_SPL_OS_BOOT is not supported yet
@@ -261,27 +262,51 @@ static void spi0_read_data(void *buf, u32 addr, u32 len)
 	}
 }
 
+static ulong spi_load_read(struct spl_load_info *load, ulong sector,
+			   ulong count, void *buf)
+{
+	spi0_read_data(buf, sector, count);
+
+	return count;
+}
+
 /*****************************************************************************/
 
 static int spl_spi_load_image(struct spl_image_info *spl_image,
 			      struct spl_boot_device *bootdev)
 {
-	int err;
+	int ret = 0;
 	struct image_header *header;
 	header = (struct image_header *)(CONFIG_SYS_TEXT_BASE);
 
 	spi0_init();
 
 	spi0_read_data((void *)header, CONFIG_SYS_SPI_U_BOOT_OFFS, 0x40);
-	err = spl_parse_image_header(spl_image, header);
-	if (err)
-		return err;
 
-	spi0_read_data((void *)spl_image->load_addr, CONFIG_SYS_SPI_U_BOOT_OFFS,
-		       spl_image->size);
+        if (IS_ENABLED(CONFIG_SPL_LOAD_FIT) &&
+		image_get_magic(header) == FDT_MAGIC) {
+		struct spl_load_info load;
+
+		debug("Found FIT image\n");
+		load.dev = NULL;
+		load.priv = NULL;
+		load.filename = NULL;
+		load.bl_len = 1;
+		load.read = spi_load_read;
+		ret = spl_load_simple_fit(spl_image, &load,
+					  CONFIG_SYS_SPI_U_BOOT_OFFS, header);
+	} else {
+		ret = spl_parse_image_header(spl_image, header);
+		if (ret)
+			return ret;
+
+		spi0_read_data((void *)spl_image->load_addr,
+			       CONFIG_SYS_SPI_U_BOOT_OFFS, spl_image->size);
+	}
 
 	spi0_deinit();
-	return 0;
+
+	return ret;
 }
 /* Use priorty 0 to override the default if it happens to be linked in */
 SPL_LOAD_IMAGE_METHOD("sunxi SPI", 0, BOOT_DEVICE_SPI, spl_spi_load_image);