watchdog: imx2_wdt: add restart handler support

Register the watchdog as the system restart function to the new introducing kernel restart call chain in the driver instead of providing the restart in machine desc. This restart handler function is from the mxc_restart() in arch/arm/mach-imx/system.c Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: imx2_wdt: add restart handler support
Register the watchdog as the system restart function to the new introducing kernel restart call chain in the driver instead of providing the restart in machine desc. This restart handler function is from the mxc_restart() in arch/arm/mach-imx/system.c Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Jingchang Lu · Wim Van Sebroeck
1 parent 05e487d905
Showing 1 changed file with 37 additions and 0 deletions Side-by-side Diff
drivers/watchdog/imx2_wdt.c
@@ -22,14 +22,17 @@
  */
  
 #include <linux/clk.h>
+#include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/jiffies.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/notifier.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
+#include <linux/reboot.h>
 #include <linux/regmap.h>
 #include <linux/timer.h>
 #include <linux/watchdog.h>
@@ -59,6 +62,7 @@
 	struct regmap *regmap;
 	struct timer_list timer;	/* Pings the watchdog when closed */
 	struct watchdog_device wdog;
+	struct notifier_block restart_handler;
 };
  
 static bool nowayout = WATCHDOG_NOWAYOUT;
@@ -77,6 +81,31 @@
 	.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 };
  
+static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
+				void *cmd)
+{
+	unsigned int wcr_enable = IMX2_WDT_WCR_WDE;
+	struct imx2_wdt_device *wdev = container_of(this,
+						    struct imx2_wdt_device,
+						    restart_handler);
+	/* Assert SRS signal */
+	regmap_write(wdev->regmap, 0, wcr_enable);
+	/*
+	 * Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be
+	 * written twice), we add another two writes to ensure there must be at
+	 * least two writes happen in the same one 32kHz clock period.  We save
+	 * the target check here, since the writes shouldn't be a huge burden
+	 * for other platforms.
+	 */
+	regmap_write(wdev->regmap, 0, wcr_enable);
+	regmap_write(wdev->regmap, 0, wcr_enable);
+
+	/* wait for reset to assert... */
+	mdelay(500);
+
+	return NOTIFY_DONE;
+}
+
 static inline void imx2_wdt_setup(struct watchdog_device *wdog)
 {
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
@@ -251,6 +280,12 @@
 		return ret;
 	}
  
+	wdev->restart_handler.notifier_call = imx2_restart_handler;
+	wdev->restart_handler.priority = 128;
+	ret = register_restart_handler(&wdev->restart_handler);
+	if (ret)
+		dev_err(&pdev->dev, "cannot register restart handler\n");
+
 	dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n",
 		 wdog->timeout, nowayout);
  
@@ -261,6 +296,8 @@
 {
 	struct watchdog_device *wdog = platform_get_drvdata(pdev);
 	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
+
+	unregister_restart_handler(&wdev->restart_handler);
  
 	watchdog_unregister_device(wdog);
...	...	@@ -22,14 +22,17 @@
22	22	*/
23	23
24	24	#include <linux/clk.h>
	25	+#include <linux/delay.h>
25	26	#include <linux/init.h>
26	27	#include <linux/io.h>
27	28	#include <linux/jiffies.h>
28	29	#include <linux/kernel.h>
29	30	#include <linux/module.h>
30	31	#include <linux/moduleparam.h>
	32	+#include <linux/notifier.h>
31	33	#include <linux/of_address.h>
32	34	#include <linux/platform_device.h>
	35	+#include <linux/reboot.h>
33	36	#include <linux/regmap.h>
34	37	#include <linux/timer.h>
35	38	#include <linux/watchdog.h>
...	...	@@ -59,6 +62,7 @@
59	62	struct regmap *regmap;
60	63	struct timer_list timer; /* Pings the watchdog when closed */
61	64	struct watchdog_device wdog;
	65	+ struct notifier_block restart_handler;
62	66	};
63	67
64	68	static bool nowayout = WATCHDOG_NOWAYOUT;
...	...	@@ -77,6 +81,31 @@
77	81	.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE,
78	82	};
79	83
	84	+static int imx2_restart_handler(struct notifier_block *this, unsigned long mode,
	85	+ void *cmd)
	86	+{
	87	+ unsigned int wcr_enable = IMX2_WDT_WCR_WDE;
	88	+ struct imx2_wdt_device *wdev = container_of(this,
	89	+ struct imx2_wdt_device,
	90	+ restart_handler);
	91	+ /* Assert SRS signal */
	92	+ regmap_write(wdev->regmap, 0, wcr_enable);
	93	+ /*
	94	+ * Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be
	95	+ * written twice), we add another two writes to ensure there must be at
	96	+ * least two writes happen in the same one 32kHz clock period. We save
	97	+ * the target check here, since the writes shouldn't be a huge burden
	98	+ * for other platforms.
	99	+ */
	100	+ regmap_write(wdev->regmap, 0, wcr_enable);
	101	+ regmap_write(wdev->regmap, 0, wcr_enable);
	102	+
	103	+ /* wait for reset to assert... */
	104	+ mdelay(500);
	105	+
	106	+ return NOTIFY_DONE;
	107	+}
	108	+
80	109	static inline void imx2_wdt_setup(struct watchdog_device *wdog)
81	110	{
82	111	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
...	...	@@ -251,6 +280,12 @@
251	280	return ret;
252	281	}
253	282
	283	+ wdev->restart_handler.notifier_call = imx2_restart_handler;
	284	+ wdev->restart_handler.priority = 128;
	285	+ ret = register_restart_handler(&wdev->restart_handler);
	286	+ if (ret)
	287	+ dev_err(&pdev->dev, "cannot register restart handler\n");
	288	+
254	289	dev_info(&pdev->dev, "timeout %d sec (nowayout=%d)\n",
255	290	wdog->timeout, nowayout);
256	291
...	...	@@ -261,6 +296,8 @@
261	296	{
262	297	struct watchdog_device *wdog = platform_get_drvdata(pdev);
263	298	struct imx2_wdt_device *wdev = watchdog_get_drvdata(wdog);
	299	+
	300	+ unregister_restart_handler(&wdev->restart_handler);
264	301
265	302	watchdog_unregister_device(wdog);
266	303