linux-kernel - [RESENDv5] serial: of-serial: fix up PM ops on no_console

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Message-ID: <1414401857-21121-1-git-send-email-jingchang.lu@freescale.com>
Date:	Mon, 27 Oct 2014 17:24:17 +0800
From:	Jingchang Lu <jingchang.lu@...escale.com>
To:	<gregkh@...uxfoundation.org>
CC:	<linux-serial@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	Jingchang Lu <jingchang.lu@...escale.com>
Subject: [RESENDv5] serial: of-serial: fix up PM ops on no_console_suspend and port type

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.

Reported-By: Joseph Lo <josephl@...dia.com>
Signed-off-by: Jingchang Lu <jingchang.lu@...escale.com>
Tested-By: Joseph Lo <josephl@...dia.com>
Reviewed-by: Peter Hurley <peter@...leysoftware.com>
---
changes in v5: 
 add missing <linux/console.h> include.

changes in v4:
 separate 8250 port suspend/resume from of_serial_suspend/resume.

changes in v3:
 fix up point reference and deference.

changes in v2:
 add switch selection on uart type.

 drivers/tty/serial/of_serial.c | 53 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index 8bc2563..9c64ad2 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>
@@ -241,13 +242,48 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
 }
 
 #ifdef CONFIG_PM_SLEEP
-static int of_serial_suspend(struct device *dev)
+#ifdef CONFIG_SERIAL_8250
+static void of_serial_suspend_8250(struct of_serial_info *info)
 {
-	struct of_serial_info *info = dev_get_drvdata(dev);
+	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
+	struct uart_port *port = &port8250->port;
 
 	serial8250_suspend_port(info->line);
-	if (info->clk)
+	if (info->clk && (!uart_console(port) || console_suspend_enabled))
 		clk_disable_unprepare(info->clk);
+}
+
+static void of_serial_resume_8250(struct of_serial_info *info)
+{
+	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
+	struct uart_port *port = &port8250->port;
+
+	if (info->clk && (!uart_console(port) || console_suspend_enabled))
+		clk_prepare_enable(info->clk);
+
+	serial8250_resume_port(info->line);
+}
+#else
+static inline void of_serial_suspend_8250(struct of_serial_info *info)
+{
+}
+
+static inline void of_serial_resume_8250(struct of_serial_info *info)
+{
+}
+#endif
+
+static int of_serial_suspend(struct device *dev)
+{
+	struct of_serial_info *info = dev_get_drvdata(dev);
+
+	switch(info->type) {
+	case PORT_8250 ... PORT_MAX_8250:
+		of_serial_suspend_8250(info);
+		break;
+	default:
+		break;
+	}
 
 	return 0;
 }
@@ -256,10 +292,13 @@ 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);
-
-	serial8250_resume_port(info->line);
+	switch(info->type) {
+	case PORT_8250 ... PORT_MAX_8250:
+		of_serial_resume_8250(info);
+		break;
+	default:
+		break;
+	}
 
 	return 0;
 }
-- 
1.8.0

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