diff options
Diffstat (limited to 'drivers/watchdog/at91sam9_wdt.c')
| -rw-r--r-- | drivers/watchdog/at91sam9_wdt.c | 320 |
1 files changed, 236 insertions, 84 deletions
diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c index be37dde4f86..489729b2629 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) ? (((s) << 8) - 1) : 0) + +#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 +120,21 @@ 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); - } else + 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) -{ - /* 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); + struct at91wdt *wdt = to_wdt(wdd); + /* calculate when the next userspace timeout will be */ + wdt->next_heartbeat = jiffies + wdd->timeout * HZ; return 0; } @@ -122,39 +147,104 @@ static int at91_wdt_stop(struct watchdog_device *wdd) static int at91_wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_timeout) { wdd->timeout = new_timeout; - return 0; + return at91_wdt_start(wdd); } -/* - * 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; + unsigned long max_heartbeat; + struct device *dev = &pdev->dev; + + 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); + } + } + + if (tmp & AT91_WDT_WDDIS) { + if (wdt->mr & AT91_WDT_WDDIS) + return 0; + dev_err(dev, "watchdog is disabled\n"); + return -EINVAL; + } + + value = tmp & AT91_WDT_WDV; + delta = (tmp & AT91_WDT_WDD) >> 16; + + if (delta < value) + min_heartbeat = ticks_to_hz_roundup(value - delta); + + max_heartbeat = ticks_to_hz_rounddown(value); + if (!max_heartbeat) { + dev_err(dev, + "heartbeat is too small for the system to handle it correctly\n"); + return -EINVAL; } /* - * All counting occurs at SLOW_CLOCK / 128 = 256 Hz - * - * Since WDV is a 12-bit counter, the maximum period is - * 4096 / 256 = 16 seconds. + * Try to reset the watchdog counter 4 or 2 times more often than + * actually requested, to avoid spurious watchdog reset. + * If this is not possible because of the min_heartbeat value, reset + * it at the min_heartbeat period. */ - 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 ((max_heartbeat / 4) >= min_heartbeat) + wdt->heartbeat = max_heartbeat / 4; + else if ((max_heartbeat / 2) >= min_heartbeat) + wdt->heartbeat = max_heartbeat / 2; + else + wdt->heartbeat = min_heartbeat; + + if (max_heartbeat < min_heartbeat + 4) + dev_warn(dev, + "min heartbeat and max heartbeat might be too close for the system to handle it correctly\n"); + + 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(dev, + "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); + + /* + * Use min_heartbeat the first time to avoid spurious watchdog reset: + * we don't know for how long the watchdog counter is running, and + * - resetting it right now might trigger a watchdog fault reset + * - waiting for heartbeat time might lead to a watchdog timeout + * reset + */ + mod_timer(&wdt->timer, jiffies + min_heartbeat); + + /* Try to set timeout from device tree first */ + if (watchdog_init_timeout(&wdt->wdd, 0, dev)) + watchdog_init_timeout(&wdt->wdd, heartbeat, 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; } /* ......................................................................... */ @@ -169,61 +259,123 @@ static const struct watchdog_ops at91_wdt_ops = { .owner = THIS_MODULE, .start = at91_wdt_start, .stop = at91_wdt_stop, - .ping = at91_wdt_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; } |