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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ARM Secure Monitor Call watchdog driver
* Copyright (C) 2022, STMicroelectronics - All Rights Reserved
* This file is based on Linux driver drivers/watchdog/arm_smc_wdt.c
*/
#define LOG_CATEGORY UCLASS_WDT
#include <dm.h>
#include <dm/device_compat.h>
#include <linux/arm-smccc.h>
#include <linux/psci.h>
#include <wdt.h>
#define DRV_NAME "arm_smc_wdt"
#define WDT_TIMEOUT_SECS(TIMEOUT) ((TIMEOUT) / 1000)
enum smcwd_call {
SMCWD_INIT = 0,
SMCWD_SET_TIMEOUT = 1,
SMCWD_ENABLE = 2,
SMCWD_PET = 3,
SMCWD_GET_TIMELEFT = 4,
};
struct smcwd_priv_data {
u32 smc_id;
unsigned int min_timeout;
unsigned int max_timeout;
};
static int smcwd_call(struct udevice *dev, enum smcwd_call call,
unsigned long arg, struct arm_smccc_res *res)
{
struct smcwd_priv_data *priv = dev_get_priv(dev);
struct arm_smccc_res local_res;
if (!res)
res = &local_res;
arm_smccc_smc(priv->smc_id, call, arg, 0, 0, 0, 0, 0, res);
if (res->a0 == PSCI_RET_NOT_SUPPORTED)
return -ENODEV;
if (res->a0 == PSCI_RET_INVALID_PARAMS)
return -EINVAL;
if (res->a0 == PSCI_RET_DISABLED)
return -ENODATA;
if (res->a0 != PSCI_RET_SUCCESS)
return -EIO;
return 0;
}
static int smcwd_reset(struct udevice *dev)
{
return smcwd_call(dev, SMCWD_PET, 0, NULL);
}
static int smcwd_stop(struct udevice *dev)
{
return smcwd_call(dev, SMCWD_ENABLE, 0, NULL);
}
static int smcwd_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
struct smcwd_priv_data *priv = dev_get_priv(dev);
u64 timeout_sec = WDT_TIMEOUT_SECS(timeout_ms);
int err;
if (timeout_sec < priv->min_timeout || timeout_sec > priv->max_timeout) {
dev_err(dev, "Timeout value not supported\n");
return -EINVAL;
}
err = smcwd_call(dev, SMCWD_SET_TIMEOUT, timeout_sec, NULL);
if (err) {
dev_err(dev, "Timeout out configuration failed\n");
return err;
}
return smcwd_call(dev, SMCWD_ENABLE, 1, NULL);
}
static int smcwd_probe(struct udevice *dev)
{
struct smcwd_priv_data *priv = dev_get_priv(dev);
struct arm_smccc_res res;
int err;
priv->smc_id = dev_read_u32_default(dev, "arm,smc-id", 0x82003D06);
err = smcwd_call(dev, SMCWD_INIT, 0, &res);
if (err < 0) {
dev_err(dev, "Init failed %i\n", err);
return err;
}
priv->min_timeout = res.a1;
priv->max_timeout = res.a2;
/* If already started, then force u-boot to use it */
err = smcwd_call(dev, SMCWD_GET_TIMELEFT, 0, NULL);
switch (err) {
case 0:
dev_dbg(dev, "Already started\n");
wdt_set_force_autostart(dev);
break;
case -ENODATA:
dev_dbg(dev, "Not already started\n");
break;
default:
/* Optional SMCWD_GET_TIMELEFT not implemented */
break;
}
return 0;
}
static const struct wdt_ops smcwd_ops = {
.start = smcwd_start,
.stop = smcwd_stop,
.reset = smcwd_reset,
};
static const struct udevice_id smcwd_dt_ids[] = {
{ .compatible = "arm,smc-wdt" },
{}
};
U_BOOT_DRIVER(wdt_sandbox) = {
.name = "smcwd",
.id = UCLASS_WDT,
.of_match = smcwd_dt_ids,
.priv_auto = sizeof(struct smcwd_priv_data),
.probe = smcwd_probe,
.ops = &smcwd_ops,
};
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