u-boot/drivers/watchdog/wdt-uclass.c
Rasmus Villemoes 7dd2097e21 watchdog: use time_after_eq() in watchdog_reset()
Some boards don't work with the rate-limiting done in the generic
watchdog_reset() provided by wdt-uclass.

For example, on powerpc, get_timer() ceases working during bootm since
interrupts are disabled before the kernel image gets decompressed, and
when the decompression takes longer than the watchdog device
allows (or enough of the budget that the kernel doesn't get far enough
to assume responsibility for petting the watchdog), the result is a
non-booting board.

As a somewhat hacky workaround (because DT is supposed to describe
hardware), allow specifying hw_margin_ms=0 in device tree to
effectively disable the ratelimiting and actually ping the watchdog
every time watchdog_reset() is called. For that to work, the "has
enough time passed" check just needs to be tweaked a little to allow
the now==next_reset case as well.

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Reviewed-by: Stefan Roese <sr@denx.de>
2021-04-27 08:28:07 +02:00

185 lines
3.7 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 <log.h>
#include <time.h>
#include <wdt.h>
#include <asm/global_data.h>
#include <dm/device-internal.h>
#include <dm/lists.h>
DECLARE_GLOBAL_DATA_PTR;
#define WATCHDOG_TIMEOUT_SECS (CONFIG_WATCHDOG_TIMEOUT_MSECS / 1000)
/*
* Reset every 1000ms, or however often is required as indicated by a
* hw_margin_ms property.
*/
static ulong reset_period = 1000;
int initr_watchdog(void)
{
u32 timeout = WATCHDOG_TIMEOUT_SECS;
int ret;
/*
* Init watchdog: This will call the probe function of the
* watchdog driver, enabling the use of the device
*/
if (uclass_get_device_by_seq(UCLASS_WDT, 0,
(struct udevice **)&gd->watchdog_dev)) {
debug("WDT: Not found by seq!\n");
if (uclass_get_device(UCLASS_WDT, 0,
(struct udevice **)&gd->watchdog_dev)) {
printf("WDT: Not found!\n");
return 0;
}
}
if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) {
timeout = dev_read_u32_default(gd->watchdog_dev, "timeout-sec",
WATCHDOG_TIMEOUT_SECS);
reset_period = dev_read_u32_default(gd->watchdog_dev,
"hw_margin_ms",
4 * reset_period) / 4;
}
if (!CONFIG_IS_ENABLED(WATCHDOG_AUTOSTART)) {
printf("WDT: Not starting\n");
return 0;
}
ret = wdt_start(gd->watchdog_dev, timeout * 1000, 0);
if (ret != 0) {
printf("WDT: Failed to start\n");
return 0;
}
printf("WDT: Started with%s servicing (%ds timeout)\n",
IS_ENABLED(CONFIG_WATCHDOG) ? "" : "out", timeout);
return 0;
}
int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
const struct wdt_ops *ops = device_get_ops(dev);
int ret;
if (!ops->start)
return -ENOSYS;
ret = ops->start(dev, timeout_ms, flags);
if (ret == 0)
gd->flags |= GD_FLG_WDT_READY;
return ret;
}
int wdt_stop(struct udevice *dev)
{
const struct wdt_ops *ops = device_get_ops(dev);
int ret;
if (!ops->stop)
return -ENOSYS;
ret = ops->stop(dev);
if (ret == 0)
gd->flags &= ~GD_FLG_WDT_READY;
return ret;
}
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_eq(now, next_reset)) {
next_reset = now + reset_period;
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,
};