This device doesn't provide any information about boot status. As workaround we use a persitent bit to track watchdog activity.
Signed-off-by: Harald Geyer <[email protected]> --- Changes since v2: * make code ordering more consistent * move part of the commit message to a code comment * rewrite the commit message Changes since v1: * make code formatting more consistent with the rest of the driver * Cc some people who might have better documentation then I do Changes since initially posting this patch on 08/04/2015: * fix a spelling error in the commit message * rebase to a recent version drivers/rtc/rtc-stmp3xxx.c | 37 +++++++++++++++++++++++++++++++++++ drivers/watchdog/stmp3xxx_rtc_wdt.c | 6 +++++- include/linux/stmp3xxx_rtc_wdt.h | 2 ++ 3 files changed, 44 insertions(+), 1 deletion(-) diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c index ca54d03..47947ea 100644 --- a/drivers/rtc/rtc-stmp3xxx.c +++ b/drivers/rtc/rtc-stmp3xxx.c @@ -30,6 +30,7 @@ #include <linux/of.h> #include <linux/stmp_device.h> #include <linux/stmp3xxx_rtc_wdt.h> +#include <linux/watchdog.h> #define STMP3XXX_RTC_CTRL 0x0 #define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN 0x00000001 @@ -62,6 +63,9 @@ /* missing bitmask in headers */ #define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER 0x80000000 +#define STMP3XXX_RTC_PERSISTENT2 0x80 +#define STMP3XXX_RTC_PERSISTENT2_WDT_ACTIVE 0x00000001 + struct stmp3xxx_rtc_data { struct rtc_device *rtc; void __iomem *io; @@ -81,6 +85,20 @@ struct stmp3xxx_rtc_data { * The watchdog driver is passed the below accessor function via platform_data * to configure the watchdog. Locking is not needed because accessing SET/CLR * registers is atomic. + * + * Since this device doesn't report the cause of the last reset, we use + * a persistent bit to track watchdog activity. The code from the Freescale + * BSP uses the STMP3XXX_RTC_PERSISTENT1 register, which is dedicated to + * controlling the boot ROM, for this purpose. However it seems the bit + * there can't be cleared once it has been set. So we are using + * STMP3XXX_RTC_PERSISTENT2 instead, which is the first register available + * for "software use" without restriction. + * + * I (Harald Geyer <[email protected]>) don't know if the code touching the + * STMP3XXX_RTC_PERSISTENT1 register is doing anything useful. Maybe this + * is just a leftover from the BSP code, but then maybe there is something + * in the boot ROM or in some bootloader that is using this. Hard to tell + * without proper documentation about this register. */ static void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout) @@ -93,16 +111,30 @@ static void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout) rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_SET); writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER, rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_SET); + writel(STMP3XXX_RTC_PERSISTENT2_WDT_ACTIVE, + rtc_data->io + STMP3XXX_RTC_PERSISTENT2 + STMP_OFFSET_REG_SET); } else { writel(STMP3XXX_RTC_CTRL_WATCHDOGEN, rtc_data->io + STMP3XXX_RTC_CTRL + STMP_OFFSET_REG_CLR); writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER, rtc_data->io + STMP3XXX_RTC_PERSISTENT1 + STMP_OFFSET_REG_CLR); + writel(STMP3XXX_RTC_PERSISTENT2_WDT_ACTIVE, + rtc_data->io + STMP3XXX_RTC_PERSISTENT2 + STMP_OFFSET_REG_CLR); } } +static void stmp3xxx_wdt_clear_bootstatus(struct device *dev) +{ + struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev); + + writel(STMP3XXX_RTC_PERSISTENT2_WDT_ACTIVE, + rtc_data->io + STMP3XXX_RTC_PERSISTENT2 + STMP_OFFSET_REG_CLR); +} + static struct stmp3xxx_wdt_pdata wdt_pdata = { .wdt_set_timeout = stmp3xxx_wdt_set_timeout, + .wdt_clear_bootstatus = stmp3xxx_wdt_clear_bootstatus, + .bootstatus = 0, }; static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev) @@ -110,6 +142,8 @@ static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev) struct platform_device *wdt_pdev = platform_device_alloc("stmp3xxx_rtc_wdt", rtc_pdev->id); + stmp3xxx_wdt_clear_bootstatus(&rtc_pdev->dev); + if (wdt_pdev) { wdt_pdev->dev.parent = &rtc_pdev->dev; wdt_pdev->dev.platform_data = &wdt_pdata; @@ -357,6 +391,9 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev) return err; } + if (readl(STMP3XXX_RTC_PERSISTENT2 + rtc_data->io) & + STMP3XXX_RTC_PERSISTENT2_WDT_ACTIVE) + wdt_pdata.bootstatus |= WDIOF_CARDRESET; stmp3xxx_wdt_register(pdev); return 0; } diff --git a/drivers/watchdog/stmp3xxx_rtc_wdt.c b/drivers/watchdog/stmp3xxx_rtc_wdt.c index e09a01f..7609f78 100644 --- a/drivers/watchdog/stmp3xxx_rtc_wdt.c +++ b/drivers/watchdog/stmp3xxx_rtc_wdt.c @@ -52,7 +52,8 @@ static int wdt_set_timeout(struct watchdog_device *wdd, unsigned new_timeout) } static const struct watchdog_info stmp3xxx_wdt_ident = { - .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | + WDIOF_CARDRESET, .identity = "STMP3XXX RTC Watchdog", }; @@ -79,6 +80,7 @@ static int wdt_notify_sys(struct notifier_block *nb, unsigned long code, switch (code) { case SYS_DOWN: /* keep enabled, system might crash while going down */ + pdata->wdt_clear_bootstatus(dev->parent); break; case SYS_HALT: /* allow the system to actually halt */ case SYS_POWER_OFF: @@ -95,12 +97,14 @@ static struct notifier_block wdt_notifier = { static int stmp3xxx_wdt_probe(struct platform_device *pdev) { + struct stmp3xxx_wdt_pdata *pdata = dev_get_platdata(&pdev->dev); int ret; watchdog_set_drvdata(&stmp3xxx_wdd, &pdev->dev); stmp3xxx_wdd.timeout = clamp_t(unsigned, heartbeat, 1, STMP3XXX_MAX_TIMEOUT); stmp3xxx_wdd.parent = &pdev->dev; + stmp3xxx_wdd.bootstatus = pdata->bootstatus; ret = watchdog_register_device(&stmp3xxx_wdd); if (ret < 0) { diff --git a/include/linux/stmp3xxx_rtc_wdt.h b/include/linux/stmp3xxx_rtc_wdt.h index 1dd12c9..62dd9e6 100644 --- a/include/linux/stmp3xxx_rtc_wdt.h +++ b/include/linux/stmp3xxx_rtc_wdt.h @@ -10,6 +10,8 @@ struct stmp3xxx_wdt_pdata { void (*wdt_set_timeout)(struct device *dev, u32 timeout); + void (*wdt_clear_bootstatus)(struct device *dev); + unsigned int bootstatus; }; #endif /* __LINUX_STMP3XXX_RTC_WDT_H */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
