u-boot/drivers/watchdog/wdt-uclass.c
Chris Packham 6d8eae9ab7 watchdog: Handle timer wrap around
On some platforms/architectures the value from get_timer() can wrap.
This is particularly problematic when long-running code needs to measure
a time difference as is the case with watchdog_reset() which tries to
avoid tickling the watchdog too frequently.

Use time_after() from time.h instead of a plain > comparison to avoid
any issues with the time wrapping on a system that has been sitting in
u-boot for a long time.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
2020-03-16 11:25:12 +01:00

121 lines
2.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2017 Google, Inc
*/
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <hang.h>
#include <time.h>
#include <wdt.h>
#include <dm/device-internal.h>
#include <dm/lists.h>
DECLARE_GLOBAL_DATA_PTR;
int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
const struct wdt_ops *ops = device_get_ops(dev);
if (!ops->start)
return -ENOSYS;
return ops->start(dev, timeout_ms, flags);
}
int wdt_stop(struct udevice *dev)
{
const struct wdt_ops *ops = device_get_ops(dev);
if (!ops->stop)
return -ENOSYS;
return ops->stop(dev);
}
int wdt_reset(struct udevice *dev)
{
const struct wdt_ops *ops = device_get_ops(dev);
if (!ops->reset)
return -ENOSYS;
return ops->reset(dev);
}
int wdt_expire_now(struct udevice *dev, ulong flags)
{
int ret = 0;
const struct wdt_ops *ops;
debug("WDT Resetting: %lu\n", flags);
ops = device_get_ops(dev);
if (ops->expire_now) {
return ops->expire_now(dev, flags);
} else {
if (!ops->start)
return -ENOSYS;
ret = ops->start(dev, 1, flags);
if (ret < 0)
return ret;
hang();
}
return ret;
}
#if defined(CONFIG_WATCHDOG)
/*
* Called by macro WATCHDOG_RESET. This function be called *very* early,
* so we need to make sure, that the watchdog driver is ready before using
* it in this function.
*/
void watchdog_reset(void)
{
static ulong next_reset;
ulong now;
/* Exit if GD is not ready or watchdog is not initialized yet */
if (!gd || !(gd->flags & GD_FLG_WDT_READY))
return;
/* Do not reset the watchdog too often */
now = get_timer(0);
if (time_after(now, next_reset)) {
next_reset = now + 1000; /* reset every 1000ms */
wdt_reset(gd->watchdog_dev);
}
}
#endif
static int wdt_post_bind(struct udevice *dev)
{
#if defined(CONFIG_NEEDS_MANUAL_RELOC)
struct wdt_ops *ops = (struct wdt_ops *)device_get_ops(dev);
static int reloc_done;
if (!reloc_done) {
if (ops->start)
ops->start += gd->reloc_off;
if (ops->stop)
ops->stop += gd->reloc_off;
if (ops->reset)
ops->reset += gd->reloc_off;
if (ops->expire_now)
ops->expire_now += gd->reloc_off;
reloc_done++;
}
#endif
return 0;
}
UCLASS_DRIVER(wdt) = {
.id = UCLASS_WDT,
.name = "watchdog",
.flags = DM_UC_FLAG_SEQ_ALIAS,
.post_bind = wdt_post_bind,
};