-----Original Message-----
From: Joseph Lo [mailto:josephl at nvidia.com]
Sent: Monday, October 13, 2014 5:41 PM
To: Lu Jingchang-B35083; gregkh at linuxfoundation.org
Cc: devicetree at vger.kernel.org; peter at hurleysoftware.com; arnd at arndb.de;
linux-kernel at vger.kernel.org; linux-serial at vger.kernel.org; linux-arm-
kernel at lists.infradead.org
Subject: Re: [PATCHv2] serial: of-serial: fix up PM ops on
no_console_suspend and port type

Hi,

On 10/13/2014 03:37 PM, Jingchang Lu wrote:

quoted

This patch fixes commit 2dea53bf57783f243c892e99c10c6921e956aa7e,
"serial: of-serial: add PM suspend/resume support", which disables
the uart clock on suspend, but also causes a hardware hang on register
access if no_console_suspend command line option is used.

Also, not every of_serial device is an 8250 port, so the serial8250
suspend/resume functions should only be applied to a real 8250 port.

Signed-off-by: Jingchang Lu <redacted>
---
changes in v2:
  add switch selection on uart type.

After apply this, it can't build for me. I still need to apply the fix
like something below.

diff --git a/drivers/tty/serial/of_serial.c

b/drivers/tty/serial/of_serial.c
index e535f9c1563d..14c1ff4e7816 100644

--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c

@@ -9,6 +9,7 @@
  *  2 of the License, or (at your option) any later version.
  *
  */
+#include <linux/console.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/delay.h>

@@ -248,13 +249,13 @@ static int of_serial_suspend(struct device *dev)
 #ifdef CONFIG_SERIAL_8250
        case PORT_8250 ... PORT_MAX_8250:
        {
-               struct uart_8250_port port8250;
+               struct uart_8250_port *port8250;
                port8250 = serial8250_get_port(info->line);

                serial8250_suspend_port(info->line);
                if (info->clk &&
-                   (!uart_console(port8250) ||
-                    (uart_console(port8250) && console_suspend_enabled)))
+                   (!uart_console(&port8250->port) ||
+                    (uart_console(&port8250->port) &&

console_suspend_enabled)))
                        clk_disable_unprepare(info->clk);
                break;
        }

@@ -274,12 +275,12 @@ static int of_serial_resume(struct device *dev)
 #ifdef CONFIG_SERIAL_8250
        case PORT_8250 ... PORT_MAX_8250:
        {
-               struct uart_8250_port port8250;
+               struct uart_8250_port *port8250;
                port8250 = serial8250_get_port(info->line);

                if (info->clk &&
-                   (!uart_console(port8250) ||
-                    (uart_console(port8250) && console_suspend_enabled)))
+                   (!uart_console(&port8250->port) ||
+                    (uart_console(&port8250->port) &&

console_suspend_enabled)))
                        clk_prepare_enable(info->clk);

                serial8250_resume_port(info->line);

-Joseph

quoted

  drivers/tty/serial/of_serial.c | 42

++++++++++++++++++++++++++++++++++++------

quoted

  1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/of_serial.c

b/drivers/tty/serial/of_serial.c

quoted

index 8bc2563..b525383 100644

--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c

@@ -245,9 +245,24 @@ static int of_serial_suspend(struct device *dev)
  {
  	struct of_serial_info *info = dev_get_drvdata(dev);

-	serial8250_suspend_port(info->line);
-	if (info->clk)
-		clk_disable_unprepare(info->clk);
+	switch(info->type) {
+#ifdef CONFIG_SERIAL_8250
+	case PORT_8250 ... PORT_MAX_8250:
+	{
+		struct uart_8250_port port8250;
+		port8250 = serial8250_get_port(info->line);
+
+		serial8250_suspend_port(info->line);
+		if (info->clk &&
+		    (!uart_console(port8250) ||
+		     (uart_console(port8250) && console_suspend_enabled)))
+			clk_disable_unprepare(info->clk);
+		break;
+	}
+#endif
+	default:
+		break;
+	}

  	return 0;
  }

@@ -256,10 +271,25 @@ static int of_serial_resume(struct device *dev)
  {
  	struct of_serial_info *info = dev_get_drvdata(dev);

-	if (info->clk)
-		clk_prepare_enable(info->clk);
+	switch(info->type) {
+#ifdef CONFIG_SERIAL_8250
+	case PORT_8250 ... PORT_MAX_8250:
+	{
+		struct uart_8250_port port8250;
+		port8250 = serial8250_get_port(info->line);
+
+		if (info->clk &&
+		    (!uart_console(port8250) ||
+		     (uart_console(port8250) && console_suspend_enabled)))
+			clk_prepare_enable(info->clk);

-	serial8250_resume_port(info->line);
+		serial8250_resume_port(info->line);
+		break;
+	}
+#endif
+	default:
+		break;
+	}

  	return 0;
  }