fastboot: add support for continue command

The fastboot continue command is defined to exit fastboot and continue
autoboot. This commit implements the continue command and the exiting of
fastboot only. Subsequent u-boot commands can be processed after exiting
fastboot. Autoboot should implement a boot script such as "fastboot; mmc
read <...>; bootm" to fully implement the fastboot continue function.

Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Lukasz Majewski <l.majewski@samsung.com>
[TestHW: Exynos4412-Trats2]

common/cmd_fastboot.c

@@ -15,17 +15,21 @@ static int do_fastboot(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
 {
 	int ret;
 
+	g_dnl_clear_detach();
 	ret = g_dnl_register("usb_dnl_fastboot");
 	if (ret)
 		return ret;
 
 	while (1) {
+		if (g_dnl_detach())
+			break;
 		if (ctrlc())
 			break;
 		usb_gadget_handle_interrupts();
 	}
 
 	g_dnl_unregister();
+	g_dnl_clear_detach();
 	return CMD_RET_SUCCESS;
 }
 

drivers/usb/gadget/f_fastboot.c

@@ -480,6 +480,17 @@ static void cb_boot(struct usb_ep *ep, struct usb_request *req)
 	fastboot_tx_write_str("OKAY");
 }
 
+static void do_exit_on_complete(struct usb_ep *ep, struct usb_request *req)
+{
+	g_dnl_trigger_detach();
+}
+
+static void cb_continue(struct usb_ep *ep, struct usb_request *req)
+{
+	fastboot_func->in_req->complete = do_exit_on_complete;
+	fastboot_tx_write_str("OKAY");
+}
+
 #ifdef CONFIG_FASTBOOT_FLASH
 static void cb_flash(struct usb_ep *ep, struct usb_request *req)
 {
@@ -520,6 +531,9 @@ static const struct cmd_dispatch_info cmd_dispatch_info[] = {
 	}, {
 		.cmd = "boot",
 		.cb = cb_boot,
+	}, {
+		.cmd = "continue",
+		.cb = cb_continue,
 	},
 #ifdef CONFIG_FASTBOOT_FLASH
 	{