On Thu, Oct 03, 2013 at 02:19:18PM +0200, Boris BREZILLON wrote: > The at91sam9 watchdog timer can only be configured once, and the current > implementation tries to configure it in a static way: > - 2 seconds timeout > - wdt restart every 500ms > > If the timer has already been configured with different values, it returns an > error and do not create any watchdog device. > > This is not critical if the watchdog is disabled, but if it has been enabled with > different timeout values it will lead to a SoC reset. > > This patch series tries to address this issue by adapting the heartbeat value > according the WDT timer config: > - it first tries to configure the timer as requested. > - if it fails it fallbacks to the current config, adapting its heartbeat timer > to the needs > > This patch series also move to a dynamically allocated at91wdt device instead > of the static instance. > > It adds a new at91 wdt type: software. This new type make use of the at91 wdt > interrupt to trigger a software reboot. > > Finally it adds several properties to the device tree bindings. > > Signed-off-by: Boris BREZILLON <b.brezillon@xxxxxxxxxxx> Hi Boris, deeper dive this time ... > --- > drivers/watchdog/at91sam9_wdt.c | 300 ++++++++++++++++++++++++++++----------- > 1 file changed, 217 insertions(+), 83 deletions(-) > > diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c > index be37dde..8f44528 100644 > --- a/drivers/watchdog/at91sam9_wdt.c > +++ b/drivers/watchdog/at91sam9_wdt.c > @@ -19,11 +19,13 @@ > > #include <linux/errno.h> > #include <linux/init.h> > +#include <linux/interrupt.h> > #include <linux/io.h> > #include <linux/kernel.h> > #include <linux/module.h> > #include <linux/moduleparam.h> > #include <linux/platform_device.h> > +#include <linux/reboot.h> > #include <linux/types.h> > #include <linux/watchdog.h> > #include <linux/jiffies.h> > @@ -31,22 +33,33 @@ > #include <linux/bitops.h> > #include <linux/uaccess.h> > #include <linux/of.h> > +#include <linux/of_irq.h> > > #include "at91sam9_wdt.h" > > #define DRV_NAME "AT91SAM9 Watchdog" > > -#define wdt_read(field) \ > - __raw_readl(at91wdt_private.base + field) > -#define wdt_write(field, val) \ > - __raw_writel((val), at91wdt_private.base + field) > +#define wdt_read(wdt, field) \ > + __raw_readl((wdt)->base + (field)) > +#define wdt_write(wtd, field, val) \ > + __raw_writel((val), (wdt)->base + (field)) > > /* AT91SAM9 watchdog runs a 12bit counter @ 256Hz, > * use this to convert a watchdog > * value from/to milliseconds. > */ > -#define ms_to_ticks(t) (((t << 8) / 1000) - 1) > -#define ticks_to_ms(t) (((t + 1) * 1000) >> 8) > +#define ticks_to_hz_rounddown(t) ((((t) + 1) * HZ) >> 8) > +#define ticks_to_hz_roundup(t) (((((t) + 1) * HZ) + 255) >> 8) > +#define ticks_to_secs(t) (((t) + 1) >> 8) > +#define secs_to_ticks(s) (((s) << 8) - 1) > + > +#define WDT_MR_RESET 0x3FFF2FFF > + > +/* Watchdog max counter value in ticks */ > +#define WDT_COUNTER_MAX_TICKS 0xFFF > + > +/* Watchdog max delta/value in secs */ > +#define WDT_COUNTER_MAX_SECS ticks_to_secs(WDT_COUNTER_MAX_TICKS) > > /* Hardware timeout in seconds */ > #define WDT_HW_TIMEOUT 2 > @@ -66,23 +79,40 @@ module_param(nowayout, bool, 0); > MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " > "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > > -static struct watchdog_device at91_wdt_dev; > -static void at91_ping(unsigned long data); > - > -static struct { > +#define to_wdt(wdd) container_of(wdd, struct at91wdt, wdd) > +struct at91wdt { > + struct watchdog_device wdd; > void __iomem *base; > unsigned long next_heartbeat; /* the next_heartbeat for the timer */ > struct timer_list timer; /* The timer that pings the watchdog */ > -} at91wdt_private; > + u32 mr; > + u32 mr_mask; > + unsigned long heartbeat; /* WDT heartbeat in jiffies */ > + bool nowayout; > + unsigned int irq; > +}; > > /* ......................................................................... */ > > +static irqreturn_t wdt_interrupt(int irq, void *dev_id) > +{ > + struct at91wdt *wdt = (struct at91wdt *)dev_id; > + > + if (wdt_read(wdt, AT91_WDT_SR)) { > + pr_crit("at91sam9 WDT software reset\n"); > + emergency_restart(); > + pr_crit("Reboot didn't ?????\n"); > + } > + > + return IRQ_HANDLED; > +} > + > /* > * Reload the watchdog timer. (ie, pat the watchdog) > */ > -static inline void at91_wdt_reset(void) > +static inline void at91_wdt_reset(struct at91wdt *wdt) > { > - wdt_write(AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT); > + wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT); > } > > /* > @@ -90,26 +120,20 @@ static inline void at91_wdt_reset(void) > */ > static void at91_ping(unsigned long data) > { > - if (time_before(jiffies, at91wdt_private.next_heartbeat) || > - (!watchdog_active(&at91_wdt_dev))) { > - at91_wdt_reset(); > - mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT); > + struct at91wdt *wdt = (struct at91wdt *)data; > + if (time_before(jiffies, wdt->next_heartbeat) || > + !watchdog_active(&wdt->wdd)) { > + at91_wdt_reset(wdt); > + mod_timer(&wdt->timer, jiffies + wdt->heartbeat); > } else > pr_crit("I will reset your machine !\n"); > } > > static int at91_wdt_ping(struct watchdog_device *wdd) > { > + struct at91wdt *wdt = to_wdt(wdd); > /* calculate when the next userspace timeout will be */ > - at91wdt_private.next_heartbeat = jiffies + wdd->timeout * HZ; > - return 0; > -} > - > -static int at91_wdt_start(struct watchdog_device *wdd) > -{ > - /* calculate the next userspace timeout and modify the timer */ > - at91_wdt_ping(wdd); > - mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT); > + wdt->next_heartbeat = jiffies + wdd->timeout * HZ; > return 0; > } > > @@ -125,36 +149,84 @@ static int at91_wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_ti at91_wdt_set_timeout only sets the new timeout but does not update next_heartbeat. That is ok if the timeout decreases, but if it is increased (say, from 1 second to 1 minute) it might result in a missed ping as userspace will subsequently believe that the new (larger) timeout was accepted by the driver. So I think you should also call at91_wdt_ping here or set wdt->next_heartbeat directly. > return 0; > } > > -/* > - * Set the watchdog time interval in 1/256Hz (write-once) > - * Counter is 12 bit. > - */ > -static int at91_wdt_settimeout(unsigned int timeout) > +static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt) > { > - unsigned int reg; > - unsigned int mr; > - > - /* Check if disabled */ > - mr = wdt_read(AT91_WDT_MR); > - if (mr & AT91_WDT_WDDIS) { > - pr_err("sorry, watchdog is disabled\n"); > - return -EIO; > + u32 tmp; > + u32 delta; > + u32 value; > + int err; > + u32 mask = wdt->mr_mask; > + unsigned long min_heartbeat = 1; > + > + tmp = wdt_read(wdt, AT91_WDT_MR); > + if ((tmp & mask) != (wdt->mr & mask)) { > + if (tmp == WDT_MR_RESET) { > + wdt_write(wdt, AT91_WDT_MR, wdt->mr); > + tmp = wdt_read(wdt, AT91_WDT_MR); > + } > } > > - /* > - * All counting occurs at SLOW_CLOCK / 128 = 256 Hz > - * > - * Since WDV is a 12-bit counter, the maximum period is > - * 4096 / 256 = 16 seconds. > - */ > - reg = AT91_WDT_WDRSTEN /* causes watchdog reset */ > - /* | AT91_WDT_WDRPROC causes processor reset only */ > - | AT91_WDT_WDDBGHLT /* disabled in debug mode */ > - | AT91_WDT_WDD /* restart at any time */ > - | (timeout & AT91_WDT_WDV); /* timer value */ > - wdt_write(AT91_WDT_MR, reg); > + if (tmp & AT91_WDT_WDDIS) { > + if (wdt->mr & AT91_WDT_WDDIS) > + return 0; > + dev_err(wdt->wdd.parent, "watchdog is disabled\n"); Took me a while to get why you use "wdt->wdd.parent" :). I would just have passed the 'dev' argument. Your call, though. > + return -EINVAL; > + } > + > + value = tmp & AT91_WDT_WDV; > + delta = (tmp & AT91_WDT_WDD) >> 16; > + > + if (delta < value) > + min_heartbeat = ticks_to_hz_roundup(value - delta); > + > + wdt->heartbeat = ticks_to_hz_rounddown(value); > + if (!wdt->heartbeat) { > + dev_err(wdt->wdd.parent, > + "heartbeat is too small for the system to handle it correctly\n"); > + return -EINVAL; > + } > + > + if (wdt->heartbeat < min_heartbeat + 3) { > + wdt->heartbeat = min_heartbeat; > + dev_warn(wdt->wdd.parent, > + "min heartbeat and max heartbeat might be too close for the system to handle it correctly\n"); > + if (wdt->heartbeat < 4) > + dev_warn(wdt->wdd.parent, > + "heartbeat might be too small for the system to handle it correctly\n"); > + } else > + wdt->heartbeat -= 4; That means heartbeat can be 0, correct (if min_heartbeat == 1) ? Will that work ? > + > + if ((tmp & AT91_WDT_WDFIEN) && wdt->irq) { > + err = request_irq(wdt->irq, wdt_interrupt, > + IRQF_SHARED | IRQF_IRQPOLL, > + pdev->name, wdt); > + if (err) > + return err; > + } > + > + if ((tmp & wdt->mr_mask) != (wdt->mr & wdt->mr_mask)) > + dev_warn(wdt->wdd.parent, > + "watchdog already configured differently (mr = %x expecting %x)\n", > + tmp & wdt->mr_mask, wdt->mr & wdt->mr_mask); > + > + setup_timer(&wdt->timer, at91_ping, (unsigned long)wdt); > + mod_timer(&wdt->timer, jiffies + wdt->heartbeat); > + > + /* Try to set timeout from device tree first */ > + if (watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev)) > + watchdog_init_timeout(&wdt->wdd, heartbeat, &pdev->dev); > + watchdog_set_nowayout(&wdt->wdd, wdt->nowayout); > + err = watchdog_register_device(&wdt->wdd); > + if (err) > + goto out_stop_timer; > + > + wdt->next_heartbeat = jiffies + wdt->wdd.timeout * HZ; > > return 0; > + > +out_stop_timer: > + del_timer(&wdt->timer); > + return err; > } > > /* ......................................................................... */ > @@ -167,63 +239,125 @@ static const struct watchdog_info at91_wdt_info = { > > static const struct watchdog_ops at91_wdt_ops = { > .owner = THIS_MODULE, > - .start = at91_wdt_start, > + .start = at91_wdt_ping, > .stop = at91_wdt_stop, > .ping = at91_wdt_ping, Notpick, but you don't need both start and ping. If both are the same, providing start is sufficient. Given this, it might be cleaner to name the function at91_wdt_start and not provide ping. > .set_timeout = at91_wdt_set_timeout, > }; > > -static struct watchdog_device at91_wdt_dev = { > - .info = &at91_wdt_info, > - .ops = &at91_wdt_ops, > - .timeout = WDT_HEARTBEAT, > - .min_timeout = 1, > - .max_timeout = 0xFFFF, > -}; > +#if defined(CONFIG_OF) > +static int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt) > +{ > + u32 min = 0; > + u32 max = WDT_COUNTER_MAX_SECS; > + const char *tmp; > + > + /* Get the interrupts property */ > + wdt->irq = irq_of_parse_and_map(np, 0); > + if (!wdt->irq) > + dev_warn(wdt->wdd.parent, "failed to get IRQ from DT\n"); > + > + if (!of_property_read_u32_index(np, "atmel,max-heartbeat-sec", 0, > + &max)) { > + if (!max || max > WDT_COUNTER_MAX_SECS) > + max = WDT_COUNTER_MAX_SECS; > + > + if (!of_property_read_u32_index(np, "atmel,min-heartbeat-sec", > + 0, &min)) { > + if (min >= max) > + min = max - 1; > + } > + } > + > + min = secs_to_ticks(min); > + max = secs_to_ticks(max); > + > + wdt->mr_mask = 0x3FFFFFFF; > + wdt->mr = 0; > + if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) && > + !strcmp(tmp, "software")) { > + wdt->mr |= AT91_WDT_WDFIEN; > + wdt->mr_mask &= ~AT91_WDT_WDRPROC; > + } else > + wdt->mr |= AT91_WDT_WDRSTEN; > + > + if (!of_property_read_string(np, "atmel,reset-type", &tmp) && > + !strcmp(tmp, "proc")) > + wdt->mr |= AT91_WDT_WDRPROC; > + > + if (of_property_read_bool(np, "atmel,disable")) { > + wdt->mr |= AT91_WDT_WDDIS; > + wdt->mr_mask &= AT91_WDT_WDDIS; > + } > + > + if (of_property_read_bool(np, "atmel,idle-halt")) > + wdt->mr |= AT91_WDT_WDIDLEHLT; > + > + if (of_property_read_bool(np, "atmel,dbg-halt")) > + wdt->mr |= AT91_WDT_WDDBGHLT; > + > + wdt->mr |= max | ((max - min) << 16); > + > + return 0; > +} > +#else > +static inline int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt) > +{ > + return 0; > +} > +#endif > > static int __init at91wdt_probe(struct platform_device *pdev) > { > struct resource *r; > - int res; > + int err; > + struct at91wdt *wdt; > > - r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > - if (!r) > - return -ENODEV; > - at91wdt_private.base = ioremap(r->start, resource_size(r)); > - if (!at91wdt_private.base) { > - dev_err(&pdev->dev, "failed to map registers, aborting.\n"); > + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); > + if (!wdt) > return -ENOMEM; > - } > > - at91_wdt_dev.parent = &pdev->dev; > - watchdog_init_timeout(&at91_wdt_dev, heartbeat, &pdev->dev); > - watchdog_set_nowayout(&at91_wdt_dev, nowayout); > + wdt->mr = (WDT_HW_TIMEOUT * 256) | AT91_WDT_WDRSTEN | AT91_WDT_WDD | > + AT91_WDT_WDDBGHLT | AT91_WDT_WDIDLEHLT; > + wdt->mr_mask = 0x3FFFFFFF; > + wdt->nowayout = nowayout; > + wdt->wdd.parent = &pdev->dev; > + wdt->wdd.info = &at91_wdt_info; > + wdt->wdd.ops = &at91_wdt_ops; > + wdt->wdd.timeout = WDT_HEARTBEAT; > + wdt->wdd.min_timeout = 1; > + wdt->wdd.max_timeout = 0xFFFF; > > - /* Set watchdog */ > - res = at91_wdt_settimeout(ms_to_ticks(WDT_HW_TIMEOUT * 1000)); > - if (res) > - return res; > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + wdt->base = devm_ioremap_resource(&pdev->dev, r); > + if (IS_ERR(wdt->base)) > + return PTR_ERR(wdt->base); > + > + if (pdev->dev.of_node) { > + err = of_at91wdt_init(pdev->dev.of_node, wdt); > + if (err) > + return err; > + } > > - res = watchdog_register_device(&at91_wdt_dev); > - if (res) > - return res; > + err = at91_wdt_init(pdev, wdt); > + if (err) > + return err; > > - at91wdt_private.next_heartbeat = jiffies + at91_wdt_dev.timeout * HZ; > - setup_timer(&at91wdt_private.timer, at91_ping, 0); > - mod_timer(&at91wdt_private.timer, jiffies + WDT_TIMEOUT); > + platform_set_drvdata(pdev, wdt); > > pr_info("enabled (heartbeat=%d sec, nowayout=%d)\n", > - at91_wdt_dev.timeout, nowayout); > + wdt->wdd.timeout, wdt->nowayout); > > return 0; > } > > static int __exit at91wdt_remove(struct platform_device *pdev) > { > - watchdog_unregister_device(&at91_wdt_dev); > + struct at91wdt *wdt = platform_get_drvdata(pdev); > + watchdog_unregister_device(&wdt->wdd); > > pr_warn("I quit now, hardware will probably reboot!\n"); > - del_timer(&at91wdt_private.timer); > + del_timer(&wdt->timer); > > return 0; > } > -- > 1.7.9.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html