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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017 Pengutronix, Lucas Stach <l.stach@pengutronix.de>
*
* Based on code from Carlo Caione <carlo@carlocaione.org>
*/
#include <common.h>
#include <init.h>
#include <io.h>
#include <restart.h>
#include <watchdog.h>
#include <soc/bcm283x/wdt.h>
#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
/* Largest value where SECS_TO_WDOG_TICKS doesn't overflow 20 bits
* (PM_WDOG_TIME_SET) */
#define WDOG_SECS_MAX 15
struct bcm2835_wd {
struct watchdog wd;
void __iomem *base;
struct device_d *dev;
struct restart_handler restart;
};
#define RESET_TIMEOUT 10
static void __noreturn bcm2835_restart_soc(struct restart_handler *rst)
{
struct bcm2835_wd *priv = container_of(rst, struct bcm2835_wd, restart);
uint32_t rstc;
rstc = readl(priv->base + PM_RSTC);
rstc &= ~PM_RSTC_WRCFG_SET;
rstc |= PM_RSTC_WRCFG_FULL_RESET;
writel(PM_PASSWORD | RESET_TIMEOUT, priv->base + PM_WDOG);
writel(PM_PASSWORD | rstc, priv->base + PM_RSTC);
hang();
}
static int bcm2835_wd_set_timeout(struct watchdog *wd, unsigned timeout)
{
struct bcm2835_wd *priv = container_of(wd, struct bcm2835_wd, wd);
u32 val;
if (!timeout) {
writel(PM_PASSWORD | PM_RSTC_RESET, priv->base + PM_RSTC);
return 0;
}
writel(PM_PASSWORD | (SECS_TO_WDOG_TICKS(timeout) & PM_WDOG_TIME_SET),
priv->base + PM_WDOG);
val = readl(priv->base + PM_RSTC);
writel(PM_PASSWORD | (val & PM_RSTC_WRCFG_CLR) |
PM_RSTC_WRCFG_FULL_RESET, priv->base + PM_RSTC);
return 0;
}
static int bcm2835_wd_probe(struct device_d *dev)
{
struct resource *iores;
struct bcm2835_wd *priv;
int ret;
priv = xzalloc(sizeof(*priv));
iores = dev_request_mem_resource(dev, 0);
if (IS_ERR(iores)) {
dev_err(dev, "could not get memory region\n");
return PTR_ERR(iores);
}
priv->base = IOMEM(iores->start);
priv->wd.set_timeout = bcm2835_wd_set_timeout;
priv->wd.timeout_max = WDOG_SECS_MAX;
priv->wd.hwdev = dev;
priv->dev = dev;
if (IS_ENABLED(CONFIG_WATCHDOG_BCM2835)) {
ret = watchdog_register(&priv->wd);
if (ret) {
free(priv);
return ret;
}
}
priv->restart.name = "bcm2835_wd";
priv->restart.restart = bcm2835_restart_soc;
restart_handler_register(&priv->restart);
return 0;
}
static __maybe_unused struct of_device_id bcm2835_wd_dt_ids[] = {
{
.compatible = "brcm,bcm2835-pm-wdt",
}, {
/* sentinel */
},
};
static struct driver_d bcm2835_wd_driver = {
.name = "bcm2835_wd",
.of_compatible = DRV_OF_COMPAT(bcm2835_wd_dt_ids),
.probe = bcm2835_wd_probe,
};
device_platform_driver(bcm2835_wd_driver);
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