cmd: fastboot: Add keyed abort option

Works the same as CONFIG_CMD_UMS_ABORT_KEYED does: any keypress will
abort fastboot mode (rather than only ctrl-c).

Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
Tested-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
Reviewed-by: Casey Connolly <casey.connolly@linaro.org>
Signed-off-by: Sam Day <me@samcday.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Link: https://patch.msgid.link/20260619-fastboot-abort-keyed-v2-1-684e53949a42@samcday.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@kernel.org>

cmd/Kconfig

@@ -1208,6 +1208,13 @@ config CMD_FASTBOOT
 
 	  See doc/android/fastboot.rst for more information.
 
+config CMD_FASTBOOT_ABORT_KEYED
+	bool "fastboot abort with any key"
+	depends on CMD_FASTBOOT && USB_FUNCTION_FASTBOOT
+	help
+	  Allow interruption of USB fastboot mode by any key presses,
+	  rather than just Ctrl-c.
+
 config CMD_FLASH
 	bool "flinfo, erase, protect"
 	default y

cmd/fastboot.c

@@ -103,8 +103,15 @@ static int do_fastboot_usb(int argc, char *const argv[],
 	while (1) {
 		if (g_dnl_detach())
 			break;
-		if (ctrlc())
+		if (IS_ENABLED(CONFIG_CMD_FASTBOOT_ABORT_KEYED)) {
+			if (tstc()) {
+				getchar();
+				puts("\rOperation aborted.\n");
+				break;
+			}
+		} else if (ctrlc()) {
 			break;
+		}
 		schedule();
 		dm_usb_gadget_handle_interrupts(udc);
 	}

doc/android/fastboot.rst

@@ -217,6 +217,10 @@ It's possible to interrupt the fastboot command using Ctrl-c::
    => fastboot usb 0
    Operation aborted.
 
+``CONFIG_CMD_FASTBOOT_ABORT_KEYED`` can be enabled so that *any* keypress
+will interrupt the fastboot command, rather than just Ctrl-c. This can be
+quite useful on mobile devices which lack a means to input Ctrl-c.
+
 You can also specify a kernel image to boot. You have to either specify
 the an image in Android format *or* pass a binary kernel and let the
 fastboot client wrap the Android suite around it. On OMAP for instance you