From: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
To: a.zummo@towertech.it, alexandre.belloni@bootlin.com
Cc: linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org,
Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Subject: [PATCH] RTC: Implement pretimeout watchdog for DS1307
Date: Tue, 4 Aug 2020 17:17:43 +1200 [thread overview]
Message-ID: <20200804051743.19115-1-mark.tomlinson@alliedtelesis.co.nz> (raw)
If the hardware watchdog in the clock chip simply pulls the reset line
of the CPU, then there is no chance to write a stack trace to help
determine what may have been blocking the CPU.
This patch adds a pretimeout to the watchdog, which, if enabled, sets
a timer to go off before the hardware watchdog kicks in, and calls
the standard pretimeout function, which can (for example) call panic.
Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
---
drivers/rtc/rtc-ds1307.c | 35 ++++++++++++++++++++++++++++++++++-
1 file changed, 34 insertions(+), 1 deletion(-)
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 49702942bb08..647f8659d0bd 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -23,6 +23,7 @@
#include <linux/clk-provider.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>
+#include <linux/timer.h>
/*
* We can't determine type by probing, but if we expect pre-Linux code
@@ -174,6 +175,10 @@ struct ds1307 {
#ifdef CONFIG_COMMON_CLK
struct clk_hw clks[2];
#endif
+#ifdef CONFIG_WATCHDOG_CORE
+ struct timer_list soft_timer;
+ struct watchdog_device *wdt;
+#endif
};
struct chip_desc {
@@ -863,12 +868,34 @@ static int m41txx_rtc_set_offset(struct device *dev, long offset)
}
#ifdef CONFIG_WATCHDOG_CORE
+static void ds1388_soft_wdt_expire(struct timer_list *soft_timer)
+{
+ struct ds1307 *ds1307 = container_of(soft_timer, struct ds1307, soft_timer);
+
+ watchdog_notify_pretimeout(ds1307->wdt);
+}
+
+static void ds1388_soft_timer_set(struct watchdog_device *wdt_dev)
+{
+ struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
+ int soft_timeout;
+
+ if (wdt_dev->pretimeout > 0) {
+ soft_timeout = wdt_dev->timeout - wdt_dev->pretimeout;
+ mod_timer(&ds1307->soft_timer, jiffies + soft_timeout * HZ);
+ } else {
+ del_timer(&ds1307->soft_timer);
+ }
+}
+
static int ds1388_wdt_start(struct watchdog_device *wdt_dev)
{
struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
u8 regs[2];
int ret;
+ ds1388_soft_timer_set(wdt_dev);
+
ret = regmap_update_bits(ds1307->regmap, DS1388_REG_FLAG,
DS1388_BIT_WF, 0);
if (ret)
@@ -900,6 +927,7 @@ static int ds1388_wdt_stop(struct watchdog_device *wdt_dev)
{
struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
+ del_timer(&ds1307->soft_timer);
return regmap_update_bits(ds1307->regmap, DS1388_REG_CONTROL,
DS1388_BIT_WDE | DS1388_BIT_RST, 0);
}
@@ -909,6 +937,7 @@ static int ds1388_wdt_ping(struct watchdog_device *wdt_dev)
struct ds1307 *ds1307 = watchdog_get_drvdata(wdt_dev);
u8 regs[2];
+ ds1388_soft_timer_set(wdt_dev);
return regmap_bulk_read(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
sizeof(regs));
}
@@ -923,6 +952,7 @@ static int ds1388_wdt_set_timeout(struct watchdog_device *wdt_dev,
regs[0] = 0;
regs[1] = bin2bcd(wdt_dev->timeout);
+ ds1388_soft_timer_set(wdt_dev);
return regmap_bulk_write(ds1307->regmap, DS1388_REG_WDOG_HUN_SECS, regs,
sizeof(regs));
}
@@ -1652,7 +1682,8 @@ static void ds1307_clks_register(struct ds1307 *ds1307)
#ifdef CONFIG_WATCHDOG_CORE
static const struct watchdog_info ds1388_wdt_info = {
- .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE | WDIOF_PRETIMEOUT,
.identity = "DS1388 watchdog",
};
@@ -1681,6 +1712,8 @@ static void ds1307_wdt_register(struct ds1307 *ds1307)
wdt->timeout = 99;
wdt->max_timeout = 99;
wdt->min_timeout = 1;
+ ds1307->wdt = wdt;
+ timer_setup(&ds1307->soft_timer, ds1388_soft_wdt_expire, 0);
watchdog_init_timeout(wdt, 0, ds1307->dev);
watchdog_set_drvdata(wdt, ds1307);
--
2.28.0
next reply other threads:[~2020-08-04 5:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-04 5:17 Mark Tomlinson [this message]
2020-08-04 15:20 ` [PATCH] RTC: Implement pretimeout watchdog for DS1307 Alexandre Belloni
2020-08-04 16:14 ` Guenter Roeck
2020-08-04 21:38 ` Chris Packham
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