serial: tty: uartlite: fix console setup

[ Upstream commit d157fca ]

Remove the hack to assign the global console_port variable at probe time.
This assumption that cons->index is -1 is wrong for systems that specify
'console=' in the cmdline (or 'stdout-path' in dts). Hence, on such system
the actual console assignment is ignored, and the first UART that happens
to be probed is used as console instead.

Move the logic to console_setup() and map the console to the correct port
through the array of available ports instead.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Link: https://lore.kernel.org/r/20210528133321.1859346-1-daniel@zonque.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/tty/serial/uartlite.c

@@ -505,21 +505,23 @@ static void ulite_console_write(struct console *co, const char *s,
 
 static int ulite_console_setup(struct console *co, char *options)
 {
-	struct uart_port *port;
+	struct uart_port *port = NULL;
 	int baud = 9600;
 	int bits = 8;
 	int parity = 'n';
 	int flow = 'n';
 
-
-	port = console_port;
+	if (co->index >= 0 && co->index < ULITE_NR_UARTS)
+		port = ulite_ports + co->index;
 
 	/* Has the device been initialized yet? */
-	if (!port->mapbase) {
+	if (!port || !port->mapbase) {
 		pr_debug("console on ttyUL%i not present\n", co->index);
 		return -ENODEV;
 	}
 
+	console_port = port;
+
 	/* not initialized yet? */
 	if (!port->membase) {
 		if (ulite_request_port(port))
@@ -655,17 +657,6 @@ static int ulite_assign(struct device *dev, int id, u32 base, int irq,
 
 	dev_set_drvdata(dev, port);
 
-#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
-	/*
-	 * If console hasn't been found yet try to assign this port
-	 * because it is required to be assigned for console setup function.
-	 * If register_console() don't assign value, then console_port pointer
-	 * is cleanup.
-	 */
-	if (ulite_uart_driver.cons->index == -1)
-		console_port = port;
-#endif
-
 	/* Register the port */
 	rc = uart_add_one_port(&ulite_uart_driver, port);
 	if (rc) {
@@ -675,12 +666,6 @@ static int ulite_assign(struct device *dev, int id, u32 base, int irq,
 		return rc;
 	}
 
-#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
-	/* This is not port which is used for console that's why clean it up */
-	if (ulite_uart_driver.cons->index == -1)
-		console_port = NULL;
-#endif
-
 	return 0;
 }