fastboot: add support for "oem format" command

Add "oem format" command to write partition table. This relies on the
env variable partitions to contain the list of partitions as required by
the gpt command.

Note that this does not erase any data other than the partition table.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Steve Rae <srae@broadcom.com>

drivers/usb/gadget/f_fastboot.c

@@ -516,6 +516,17 @@ static void cb_flash(struct usb_ep *ep, struct usb_request *req)
 static void cb_oem(struct usb_ep *ep, struct usb_request *req)
 {
 	char *cmd = req->buf;
+#ifdef CONFIG_FASTBOOT_FLASH
+	if (strncmp("format", cmd + 4, 6) == 0) {
+		char cmdbuf[32];
+                sprintf(cmdbuf, "gpt write mmc %x $partitions",
+			CONFIG_FASTBOOT_FLASH_MMC_DEV);
+                if (run_command(cmdbuf, 0))
+			fastboot_tx_write_str("FAIL");
+                else
+			fastboot_tx_write_str("OKAY");
+	} else
+#endif
 	if (strncmp("unlock", cmd + 4, 8) == 0) {
 		fastboot_tx_write_str("FAILnot implemented");
 	}