serial: 8250_omap: Fix errors with no_console_suspend

We now get errors on system suspend if no_console_suspend is set as
reported by Thomas. The errors started with commit 20a41a6 ("serial:
8250_omap: Use force_suspend and resume for system suspend").

Let's fix the issue by checking for console_suspend_enabled in the system
suspend and resume path.

Note that with this fix the checks for console_suspend_enabled in
omap8250_runtime_suspend() become useless. We now keep runtime PM usage
count for an attached kernel console starting with commit bedb404
("serial: 8250_port: Don't use power management for kernel console").

Fixes: 20a41a6 ("serial: 8250_omap: Use force_suspend and resume for system suspend")
Cc: stable <stable@kernel.org>
Cc: Udit Kumar <u-kumar1@ti.com>
Reported-by: Thomas Richard <thomas.richard@bootlin.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Tested-by: Thomas Richard <thomas.richard@bootlin.com>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Link: https://lore.kernel.org/r/20230926061319.15140-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: tmlind

drivers/tty/serial/8250/8250_omap.c

@@ -1617,7 +1617,7 @@ static int omap8250_suspend(struct device *dev)
 {
 	struct omap8250_priv *priv = dev_get_drvdata(dev);
 	struct uart_8250_port *up = serial8250_get_port(priv->line);
-	int err;
+	int err = 0;
 
 	serial8250_suspend_port(priv->line);
 
@@ -1627,7 +1627,8 @@ static int omap8250_suspend(struct device *dev)
 	if (!device_may_wakeup(dev))
 		priv->wer = 0;
 	serial_out(up, UART_OMAP_WER, priv->wer);
-	err = pm_runtime_force_suspend(dev);
+	if (uart_console(&up->port) && console_suspend_enabled)
+		err = pm_runtime_force_suspend(dev);
 	flush_work(&priv->qos_work);
 
 	return err;
@@ -1636,11 +1637,15 @@ static int omap8250_suspend(struct device *dev)
 static int omap8250_resume(struct device *dev)
 {
 	struct omap8250_priv *priv = dev_get_drvdata(dev);
+	struct uart_8250_port *up = serial8250_get_port(priv->line);
 	int err;
 
-	err = pm_runtime_force_resume(dev);
-	if (err)
-		return err;
+	if (uart_console(&up->port) && console_suspend_enabled) {
+		err = pm_runtime_force_resume(dev);
+		if (err)
+			return err;
+	}
+
 	serial8250_resume_port(priv->line);
 	/* Paired with pm_runtime_resume_and_get() in omap8250_suspend() */
 	pm_runtime_mark_last_busy(dev);
@@ -1717,16 +1722,6 @@ static int omap8250_runtime_suspend(struct device *dev)
 
 	if (priv->line >= 0)
 		up = serial8250_get_port(priv->line);
-	/*
-	 * When using 'no_console_suspend', the console UART must not be
-	 * suspended. Since driver suspend is managed by runtime suspend,
-	 * preventing runtime suspend (by returning error) will keep device
-	 * active during suspend.
-	 */
-	if (priv->is_suspending && !console_suspend_enabled) {
-		if (up && uart_console(&up->port))
-			return -EBUSY;
-	}
 
 	if (priv->habit & UART_ERRATA_CLOCK_DISABLE) {
 		int ret;