Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754229Ab3JBQMO (ORCPT ); Wed, 2 Oct 2013 12:12:14 -0400 Received: from mail-pb0-f50.google.com ([209.85.160.50]:49139 "EHLO mail-pb0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753644Ab3JBQMK (ORCPT ); Wed, 2 Oct 2013 12:12:10 -0400 Date: Wed, 2 Oct 2013 09:12:04 -0700 From: Guenter Roeck To: Boris BREZILLON Cc: Wim Van Sebroeck , Nicolas Ferre , Jean-Christophe PLAGNIOL-VILLARD , Ludovic Desroches , Yang Wenyou , linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [v2,1/4] watchdog: at91sam9_wdt: better watchdog support Message-ID: <20131002161204.GA15974@roeck-us.net> References: <1371799288-3548-1-git-send-email-b.brezillon@overkiz.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1371799288-3548-1-git-send-email-b.brezillon@overkiz.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 15253 Lines: 520 On Fri, Jun 21, 2013 at 03:21:28PM -0000, 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 > > --- > drivers/watchdog/at91sam9_wdt.c | 319 +++++++++++++++++++++++++++++---------- > 1 file changed, 236 insertions(+), 83 deletions(-) > > diff --git a/drivers/watchdog/at91sam9_wdt.c b/drivers/watchdog/at91sam9_wdt.c > index be37dde..fb47ec5 100644 > --- a/drivers/watchdog/at91sam9_wdt.c > +++ b/drivers/watchdog/at91sam9_wdt.c > @@ -19,11 +19,13 @@ > > #include > #include > +#include > #include > #include > #include > #include > #include > +#include > #include > #include > #include > @@ -31,23 +33,32 @@ > #include > #include > #include > +#include > +#include > > #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 hz_to_ticks(h) (((h << 8) / HZ) - 1) Unused. > +#define ticks_to_hz(t) (((t + 1) * HZ) >> 8) > #define ms_to_ticks(t) (((t << 8) / 1000) - 1) > #define ticks_to_ms(t) (((t + 1) * 1000) >> 8) You should put macro parameters in () to avoid undesired side effects. (h), (t), (field) Sure, some of them are old. No reason not to fix it, though. > > +#define WDT_MR_RESET 0x3FFF2FFF > + > +#define WDT_WDD_MAX 0xFFF > +#define WDT_WDV_MAX 0xFFF What are the units ? > + > /* Hardware timeout in seconds */ > #define WDT_HW_TIMEOUT 2 > > @@ -66,23 +77,41 @@ 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)) { > + /* Reboot */ That is quite obvious, isn't it ? > + 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 +119,20 @@ 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))) { Unnecessary () around !watchdog_active() [ Sure, old code. Not a reason not to clean it up ] > + 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 +148,82 @@ static int at91_wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_ti > 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; > + > + 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(wdt->wdd.parent, > + ": sorry, watchdog is disabled\n"); No need to be sorry all the time. The ':' is unnecessary. > + return -EINVAL; > + } > + > + value = tmp & AT91_WDT_WDV; > + delta = (tmp & AT91_WDT_WDD) >> 16; > + > + if (delta < value) { > + if ((value / (value - delta)) < 4) { Unnecessary ( ) around left side of equation. > + dev_err(wdt->wdd.parent, > + ": sorry, max-heartbeat should be at least 4 times min-heartbeat (max-heartbeat = %d x min-heartbeat)\n", > + (value / (value - delta))); Unnecessary ( ) around the equation. > + return -EINVAL; > + } > + } > + > + wdt->heartbeat = ticks_to_hz(value / 4); > + > + if (!wdt->heartbeat) { > + dev_err(wdt->wdd.parent, > + ": sorry, linux timer (%i Hz) cannot handle watchdog timeout (%i ms)\n", > + HZ, ticks_to_ms(value)); > + return -EINVAL; Isn't that a bit rude ? Why not set it to the minimum ? > + } > + > + 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; > } > > - /* > - * 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 & 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 +236,147 @@ 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, > .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 = 0xFFF; Are those default values ? If so might use defines (there are actually defines for 0xfff already). > + const char *tmp; > + > + wdt->base = of_iomap(np, 0); I am a bit at loss why you need to use use this function here. I think it would be more beneficial to use devm_ioremap() or even better devm_ioremap_resource() in both of and non-dt cases; then you don't have to call iounmap(). > + if (!wdt->base) { > + dev_err(wdt->wdd.parent, "failed to map registers, aborting.\n"); > + return -EINVAL; > + } > + > + /* 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)) { > + max *= 256; > + if (max > WDT_WDV_MAX) > + max = WDT_WDV_MAX; > + > + if (!of_property_read_u32_index(np, "atmel,min-heartbeat-sec", > + 0, &min)) { > + min *= 256; > + if (4 * min > max) > + min = max / 4; > + } > + } I am a bit confused about those parameters. How do they match min_timeout and max_timeout ? > + > + 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; > - > - 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"); > - return -ENOMEM; > - } > + int err; > + struct at91wdt *wdt; > > - at91_wdt_dev.parent = &pdev->dev; > - watchdog_init_timeout(&at91_wdt_dev, heartbeat, &pdev->dev); > - watchdog_set_nowayout(&at91_wdt_dev, nowayout); > + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); > + if (!wdt) > + return -ENOMEM; > > - /* Set watchdog */ > - res = at91_wdt_settimeout(ms_to_ticks(WDT_HW_TIMEOUT * 1000)); > - if (res) > - return res; > + 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; > + > + if (pdev->dev.of_node) { > + err = of_at91wdt_init(pdev->dev.of_node, wdt); > + if (err) > + goto out_free_watchdog; > + } else { > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!r) { > + err = -ENODEV; > + goto out_free_watchdog; > + } > + > + wdt->base = ioremap(r->start, resource_size(r)); > + if (!wdt->base) { > + dev_err(&pdev->dev, "failed to map registers, aborting.\n"); > + err = -ENOMEM; > + goto out_free_watchdog; > + } > + } > > - res = watchdog_register_device(&at91_wdt_dev); > - if (res) > - return res; > + err = at91_wdt_init(pdev, wdt); > + if (err) > + goto out_iounmap; > > - 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; > + > +out_iounmap: > + iounmap(wdt->base); > +out_free_watchdog: > + devm_kfree(&pdev->dev, wdt); The whole point of using devm_kzalloc() is that you don't have to call kfree() or devm_kfree(). So this call (and with it the label) is unnecessary. > + return err; > } > > 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); > + > + iounmap(wdt->base); > + devm_kfree(&pdev->dev, wdt); > The call to devm_kfree() is unnecessary. > return 0; > } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/