| Message ID | 1411108199-1280-3-git-send-email-jszhang@marvell.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/18/2014 11:29 PM, Jisheng Zhang wrote: > The kernel core now provides an API to trigger a system restart. > Register with it to support restarting the system via. watchdog. > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > --- > drivers/watchdog/dw_wdt.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c > index ad0619d..4ca41e9 100644 > --- a/drivers/watchdog/dw_wdt.c > +++ b/drivers/watchdog/dw_wdt.c > @@ -29,9 +29,11 @@ > #include <linux/miscdevice.h> > #include <linux/module.h> > #include <linux/moduleparam.h> > +#include <linux/notifier.h> > #include <linux/of.h> > #include <linux/pm.h> > #include <linux/platform_device.h> > +#include <linux/reboot.h> > #include <linux/spinlock.h> > #include <linux/timer.h> > #include <linux/uaccess.h> > @@ -62,6 +64,7 @@ static struct { > unsigned long next_heartbeat; > struct timer_list timer; > int expect_close; > + struct notifier_block restart_handler; > } dw_wdt; > > static inline int dw_wdt_is_enabled(void) > @@ -119,6 +122,22 @@ static void dw_wdt_keepalive(void) > WDOG_COUNTER_RESTART_REG_OFFSET); > } > > +static int dw_wdt_restart_handle(struct notifier_block *this, > + unsigned long mode, void *cmd) > +{ > + u32 val; > + > + writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); > + val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); > + if (val & WDOG_CONTROL_REG_WDT_EN_MASK) > + writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs + > + WDOG_COUNTER_RESTART_REG_OFFSET); > + else > + writel(WDOG_CONTROL_REG_WDT_EN_MASK, > + dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); Don't you have to write WDOG_COUNTER_RESTART_KICK_VALUE into WDOG_COUNTER_RESTART_REG_OFFSET in the else case as well ? Guenter
On 09/19/2014 08:07 PM, Guenter Roeck wrote: > On 09/18/2014 11:29 PM, Jisheng Zhang wrote: >> The kernel core now provides an API to trigger a system restart. >> Register with it to support restarting the system via. watchdog. >> >> Signed-off-by: Jisheng Zhang <jszhang@marvell.com> >> --- >> drivers/watchdog/dw_wdt.c | 27 +++++++++++++++++++++++++++ >> 1 file changed, 27 insertions(+) >> >> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c >> index ad0619d..4ca41e9 100644 >> --- a/drivers/watchdog/dw_wdt.c >> +++ b/drivers/watchdog/dw_wdt.c >> @@ -29,9 +29,11 @@ >> #include <linux/miscdevice.h> >> #include <linux/module.h> >> #include <linux/moduleparam.h> >> +#include <linux/notifier.h> >> #include <linux/of.h> >> #include <linux/pm.h> >> #include <linux/platform_device.h> >> +#include <linux/reboot.h> >> #include <linux/spinlock.h> >> #include <linux/timer.h> >> #include <linux/uaccess.h> >> @@ -62,6 +64,7 @@ static struct { >> unsigned long next_heartbeat; >> struct timer_list timer; >> int expect_close; >> + struct notifier_block restart_handler; >> } dw_wdt; >> >> static inline int dw_wdt_is_enabled(void) >> @@ -119,6 +122,22 @@ static void dw_wdt_keepalive(void) >> WDOG_COUNTER_RESTART_REG_OFFSET); >> } >> >> +static int dw_wdt_restart_handle(struct notifier_block *this, >> + unsigned long mode, void *cmd) >> +{ >> + u32 val; >> + >> + writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); >> + val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); >> + if (val & WDOG_CONTROL_REG_WDT_EN_MASK) >> + writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs + >> + WDOG_COUNTER_RESTART_REG_OFFSET); >> + else >> + writel(WDOG_CONTROL_REG_WDT_EN_MASK, >> + dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); > > Don't you have to write WDOG_COUNTER_RESTART_KICK_VALUE into > WDOG_COUNTER_RESTART_REG_OFFSET in the else case as well ? > According to the datasheet, it should be sufficient to - Write 0 into WDOG_TIMEOUT_RANGE_REG_OFFSET to select the minimum timeout period - Write 0x1 into WDOG_CONTROL_REG_OFFSET to enable the watchdog and select reset as desired action. This can be unconditional. Writing into the restart register should not be necessary. Thanks, Guenter
On 09/18/2014 11:29 PM, Jisheng Zhang wrote: > The kernel core now provides an API to trigger a system restart. > Register with it to support restarting the system via. watchdog. > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > --- > drivers/watchdog/dw_wdt.c | 27 +++++++++++++++++++++++++++ > 1 file changed, 27 insertions(+) > > diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c > index ad0619d..4ca41e9 100644 > --- a/drivers/watchdog/dw_wdt.c > +++ b/drivers/watchdog/dw_wdt.c > @@ -29,9 +29,11 @@ > #include <linux/miscdevice.h> > #include <linux/module.h> > #include <linux/moduleparam.h> > +#include <linux/notifier.h> > #include <linux/of.h> > #include <linux/pm.h> > #include <linux/platform_device.h> > +#include <linux/reboot.h> > #include <linux/spinlock.h> > #include <linux/timer.h> > #include <linux/uaccess.h> > @@ -62,6 +64,7 @@ static struct { > unsigned long next_heartbeat; > struct timer_list timer; > int expect_close; > + struct notifier_block restart_handler; > } dw_wdt; > > static inline int dw_wdt_is_enabled(void) > @@ -119,6 +122,22 @@ static void dw_wdt_keepalive(void) > WDOG_COUNTER_RESTART_REG_OFFSET); > } > > +static int dw_wdt_restart_handle(struct notifier_block *this, > + unsigned long mode, void *cmd) > +{ > + u32 val; > + > + writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); > + val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); > + if (val & WDOG_CONTROL_REG_WDT_EN_MASK) > + writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs + > + WDOG_COUNTER_RESTART_REG_OFFSET); > + else > + writel(WDOG_CONTROL_REG_WDT_EN_MASK, > + dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); Another comment: You should probably wait here for a bit to let the reset catch. Thanks, Guenter
Dear Guenter, On Sat, 20 Sep 2014 07:08:22 -0700 Guenter Roeck <linux@roeck-us.net> wrote: > On 09/19/2014 08:07 PM, Guenter Roeck wrote: > > On 09/18/2014 11:29 PM, Jisheng Zhang wrote: > >> The kernel core now provides an API to trigger a system restart. > >> Register with it to support restarting the system via. watchdog. > >> > >> Signed-off-by: Jisheng Zhang <jszhang@marvell.com> > >> --- > >> drivers/watchdog/dw_wdt.c | 27 +++++++++++++++++++++++++++ > >> 1 file changed, 27 insertions(+) > >> > >> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c > >> index ad0619d..4ca41e9 100644 > >> --- a/drivers/watchdog/dw_wdt.c > >> +++ b/drivers/watchdog/dw_wdt.c > >> @@ -29,9 +29,11 @@ > >> #include <linux/miscdevice.h> > >> #include <linux/module.h> > >> #include <linux/moduleparam.h> > >> +#include <linux/notifier.h> > >> #include <linux/of.h> > >> #include <linux/pm.h> > >> #include <linux/platform_device.h> > >> +#include <linux/reboot.h> > >> #include <linux/spinlock.h> > >> #include <linux/timer.h> > >> #include <linux/uaccess.h> > >> @@ -62,6 +64,7 @@ static struct { > >> unsigned long next_heartbeat; > >> struct timer_list timer; > >> int expect_close; > >> + struct notifier_block restart_handler; > >> } dw_wdt; > >> > >> static inline int dw_wdt_is_enabled(void) > >> @@ -119,6 +122,22 @@ static void dw_wdt_keepalive(void) > >> WDOG_COUNTER_RESTART_REG_OFFSET); > >> } > >> > >> +static int dw_wdt_restart_handle(struct notifier_block *this, > >> + unsigned long mode, void *cmd) > >> +{ > >> + u32 val; > >> + > >> + writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); > >> + val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); > >> + if (val & WDOG_CONTROL_REG_WDT_EN_MASK) > >> + writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs + > >> + WDOG_COUNTER_RESTART_REG_OFFSET); > >> + else > >> + writel(WDOG_CONTROL_REG_WDT_EN_MASK, > >> + dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); > Another comment: You should probably wait here for a bit to let the reset > catch. will do in next version. Thanks for pointing out > > > > Don't you have to write WDOG_COUNTER_RESTART_KICK_VALUE into > > WDOG_COUNTER_RESTART_REG_OFFSET in the else case as well ? > > > > According to the datasheet, it should be sufficient to > - Write 0 into WDOG_TIMEOUT_RANGE_REG_OFFSET to select the minimum timeout > period > - Write 0x1 into WDOG_CONTROL_REG_OFFSET to enable the watchdog and select > reset as desired action. This can be unconditional. > > Writing into the restart register should not be necessary. > we want to handle the reboot case if wdt is in already use. In this case, we dunno what's the timeout period, but obviously it's not as short as 2^16/clk So we change the timeout period by writing 0 into WDOG_TIMEOUT_RANGE_REG_OFFSET to select the minimum timeout period. But per the datasheet, a change of the timeout period takes effect only after the next counter restart. So we programming the restart register to kick off next counter restart. Thanks for reviewing, Jisheng
diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c index ad0619d..4ca41e9 100644 --- a/drivers/watchdog/dw_wdt.c +++ b/drivers/watchdog/dw_wdt.c @@ -29,9 +29,11 @@ #include <linux/miscdevice.h> #include <linux/module.h> #include <linux/moduleparam.h> +#include <linux/notifier.h> #include <linux/of.h> #include <linux/pm.h> #include <linux/platform_device.h> +#include <linux/reboot.h> #include <linux/spinlock.h> #include <linux/timer.h> #include <linux/uaccess.h> @@ -62,6 +64,7 @@ static struct { unsigned long next_heartbeat; struct timer_list timer; int expect_close; + struct notifier_block restart_handler; } dw_wdt; static inline int dw_wdt_is_enabled(void) @@ -119,6 +122,22 @@ static void dw_wdt_keepalive(void) WDOG_COUNTER_RESTART_REG_OFFSET); } +static int dw_wdt_restart_handle(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + u32 val; + + writel(0, dw_wdt.regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); + val = readl(dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); + if (val & WDOG_CONTROL_REG_WDT_EN_MASK) + writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt.regs + + WDOG_COUNTER_RESTART_REG_OFFSET); + else + writel(WDOG_CONTROL_REG_WDT_EN_MASK, + dw_wdt.regs + WDOG_CONTROL_REG_OFFSET); + return NOTIFY_DONE; +} + static void dw_wdt_ping(unsigned long data) { if (time_before(jiffies, dw_wdt.next_heartbeat) || @@ -315,6 +334,12 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) if (ret) goto out_disable_clk; + dw_wdt.restart_handler.notifier_call = dw_wdt_restart_handle; + dw_wdt.restart_handler.priority = 128; + ret = register_restart_handler(&dw_wdt.restart_handler); + if (ret) + pr_warn("cannot register restart handler\n"); + dw_wdt_set_next_heartbeat(); setup_timer(&dw_wdt.timer, dw_wdt_ping, 0); mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT); @@ -329,6 +354,8 @@ out_disable_clk: static int dw_wdt_drv_remove(struct platform_device *pdev) { + unregister_restart_handler(&dw_wdt.restart_handler); + misc_deregister(&dw_wdt_miscdev); clk_disable_unprepare(dw_wdt.clk);
The kernel core now provides an API to trigger a system restart. Register with it to support restarting the system via. watchdog. Signed-off-by: Jisheng Zhang <jszhang@marvell.com> --- drivers/watchdog/dw_wdt.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)