watchdog: pnx4008: add restart handler

From: Sylvain Lemieux <[email protected]>

Add restart handler capability to the driver;
the restart handler implementation was taken from
"mach-lpc32xx" ("lpc23xx_restart" function).

Signed-off-by Sylvain Lemieux <[email protected]>

---
Changes from v5 to v6:
- none.

Changes from v4 to v5:
- Rebased on the following patch:

   http://permalink.gmane.org/gmane.linux.watchdog/3364/

Changes from v3 to v4:
- none.

Changes from v2 to v3:
- remove explicit clock enable from restart handler.
- verify "register_restart_handler" return value.
- add call to unregister_restart_handler".
- do the restart handling directly in "pnx4008_restart_handler".

Changes from v1 to v2:
- new patch in v2.

  drivers/watchdog/pnx4008_wdt.c | 17 +++++++++++++++++
  1 file changed, 17 insertions(+)

drivers/watchdog/pnx4008_wdt.c +17 -0

index 88264a2..f3be522 100644
@@ -31,6 +31,8 @@
  #include <linux/slab.h>
  #include <linux/err.h>
  #include <linux/of.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
  #include <mach/hardware.h>
 
  /* WatchDog Timer - Chapter 23 Page 207 */

@@ -124,6 +126,19 @@ static int pnx4008_wdt_set_timeout(struct watchdog_device *wdd,
  	return 0;
  }
 
+static int pnx4008_restart_handler(struct watchdog_device *wdd,
+				   unsigned long mode, void *cmd)
+{
+	/* Instant assert of RESETOUT_N with pulse length 1mS */
+	writel(13000, WDTIM_PULSE(wdt_base));
+	writel(M_RES2 | RESFRC1 | RESFRC2, WDTIM_MCTRL(wdt_base));
+
+	/* Wait for watchdog to reset system */
+	mdelay(1000);
+
+	return NOTIFY_DONE;
+}
+
  static const struct watchdog_info pnx4008_wdt_ident = {
  	.options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
  	    WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,

@@ -135,6 +150,7 @@ static const struct watchdog_ops pnx4008_wdt_ops = {
  	.start = pnx4008_wdt_start,
  	.stop = pnx4008_wdt_stop,
  	.set_timeout = pnx4008_wdt_set_timeout,
+	.restart = pnx4008_restart_handler,
  };
 
  static struct watchdog_device pnx4008_wdd = {

@@ -169,6 +185,7 @@ static int pnx4008_wdt_probe(struct platform_device *pdev)
  			WDIOF_CARDRESET : 0;
  	pnx4008_wdd.parent = &pdev->dev;
  	watchdog_set_nowayout(&pnx4008_wdd, nowayout);
+	watchdog_set_restart_priority(&pnx4008_wdd, 128);
 
  	pnx4008_wdt_stop(&pnx4008_wdd);	/* disable for now */
 

From: Sylvain Lemieux <[email protected]>

Add support for explicit soft reset using the reboot mode.

The default reboot mode behavior is unchanged;
you can overwrite the default reboot type in the board specific file "DT_MACHINE_START" definition using the "reboot_mode" parameter.

Signed-off-by Sylvain Lemieux <[email protected]>

---
Changes from v5 to v6:
- remove typecast.

Changes from v4 to v5:
- no logical change; updated to work with new revision of patch #2.

Changes from v3 to v4:
- none.

Changes from v2 to v3:
- no logical change; updated to work with new revision of patch #2.

Changes from v1 to v2:
- Rename patch title;
was "arm: lpc32xx: restart: add support for soft reset"
- Add change to "pnx-4008" driver instead of "mach-lpc32xx".
- Use define available in "pnx-4008" when writting to watchdog register.

  drivers/watchdog/pnx4008_wdt.c | 13 ++++++++++---
  1 file changed, 10 insertions(+), 3 deletions(-)

drivers/watchdog/pnx4008_wdt.c +10 -3

index f3be522..51be66e 100644
@@ -129,9 +129,16 @@ static int pnx4008_wdt_set_timeout(struct watchdog_device *wdd,
  static int pnx4008_restart_handler(struct watchdog_device *wdd,
  				   unsigned long mode, void *cmd)
  {
-	/* Instant assert of RESETOUT_N with pulse length 1mS */
-	writel(13000, WDTIM_PULSE(wdt_base));
-	writel(M_RES2 | RESFRC1 | RESFRC2, WDTIM_MCTRL(wdt_base));
+	if (mode == REBOOT_SOFT) {
+		/* Force match output active */
+		writel(EXT_MATCH0, WDTIM_EMR(wdt_base));
+		/* Internal reset on match output (RESOUT_N not asserted) */
+		writel(M_RES1, WDTIM_MCTRL(wdt_base));
+	} else {
+		/* Instant assert of RESETOUT_N with pulse length 1mS */
+		writel(13000, WDTIM_PULSE(wdt_base));
+		writel(M_RES2 | RESFRC1 | RESFRC2, WDTIM_MCTRL(wdt_base));
+	}
 
  	/* Wait for watchdog to reset system */
  	mdelay(1000);

From: Sylvain Lemieux <[email protected]>

Added support to verify if a "cmd" is passed from the userspace program rebooting the system;
- if a valid "cmd" is available, handle it;
- If the received "cmd" is not supported, use the default reboot mode.

Signed-off-by Sylvain Lemieux <[email protected]>

---
Changes from v5 to v6:
- remove typecast.

Changes from v4 to v5:
- no logical change; updated to work with new revision of patch #2.

Changes from v3 to v4:
- none.

Changes from v2 to v3:
- no logical change; updated to work with new revision of patch #2.

Changes from v1 to v2:
- Rename patch title;
was "arm: lpc32xx: restart: support "cmd" from userspace"
- Add change to "pnx-4008" driver instead of "mach-lpc32xx".

  drivers/watchdog/pnx4008_wdt.c | 15 +++++++++++++++
  1 file changed, 15 insertions(+)

drivers/watchdog/pnx4008_wdt.c +0 -0

index 51be66e..4162135 100644

drivers/watchdog/pnx4008_wdt.c +14 -0

+
+	/*
+	 * Verify if a "cmd" passed from the userspace program rebooting
+	 * the system; if available, handle it.
+	 * - For details, see the 'reboot' syscall in kernel/reboot.c
+	 * - If the received "cmd" is not supported, use the default mode.
+	 */
+	if (boot_cmd) {
+		if (boot_cmd[0] == 'h')
+			mode = REBOOT_HARD;
+		else if (boot_cmd[0] == 's')
+			mode = REBOOT_SOFT;
+	}
+
  	if (mode == REBOOT_SOFT) {
  		/* Force match output active */
  		writel(EXT_MATCH0, WDTIM_EMR(wdt_base));

Quoted 33 lines · Sylvain Lemieux

From: Sylvain Lemieux <[email protected]>

Added support to verify if a "cmd" is passed from the userspace program rebooting the system;
- if a valid "cmd" is available, handle it;
- If the received "cmd" is not supported, use the default reboot mode.

Signed-off-by Sylvain Lemieux <[email protected]>

---
Changes from v5 to v6:
- remove typecast.

Changes from v4 to v5:
- no logical change; updated to work with new revision of patch #2.

Changes from v3 to v4:
- none.

Changes from v2 to v3:
- no logical change; updated to work with new revision of patch #2.

Changes from v1 to v2:
- Rename patch title;
was "arm: lpc32xx: restart: support "cmd" from userspace"
- Add change to "pnx-4008" driver instead of "mach-lpc32xx".

  drivers/watchdog/pnx4008_wdt.c | 15 +++++++++++++++
  1 file changed, 15 insertions(+)

drivers/watchdog/pnx4008_wdt.c +0 -0

index 51be66e..4162135 100644

drivers/watchdog/pnx4008_wdt.c static int pnx4008_wdt_set_timeout(struct watchdog_device *wdd, · line 132

Quoted 4 lines

drivers/watchdog/pnx4008_wdt.c +1 -0

@@ -129,6 +129,21 @@ static int pnx4008_wdt_set_timeout(struct watchdog_device *wdd,
  static int pnx4008_restart_handler(struct watchdog_device *wdd,
  				   unsigned long mode, void *cmd)
  {
+	const char *boot_cmd = (const char *)cmd;

This typecast is unnecessary.

Guenter

Quoted 19 lines

drivers/watchdog/pnx4008_wdt.c +14 -0

+
+	/*
+	 * Verify if a "cmd" passed from the userspace program rebooting
+	 * the system; if available, handle it.
+	 * - For details, see the 'reboot' syscall in kernel/reboot.c
+	 * - If the received "cmd" is not supported, use the default mode.
+	 */
+	if (boot_cmd) {
+		if (boot_cmd[0] == 'h')
+			mode = REBOOT_HARD;
+		else if (boot_cmd[0] == 's')
+			mode = REBOOT_SOFT;
+	}
+
  	if (mode == REBOOT_SOFT) {
  		/* Force match output active */
  		writel(EXT_MATCH0, WDTIM_EMR(wdt_base));