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6319fabe32
The optional SMCWD_GET_TIMELEFT command can be used to detect if the watchdog has already been started. See the implementation in OP-TEE secure OS [1]. At probe time, check if the watchdog is already started and then call wdt_set_force_autostart(). This will keep U-Boot pinging the watchdog even when the property 'u-boot,noautostart' is present. Link: https://github.com/OP-TEE/optee_os/commit/a7f2d4bd8632 [1] Signed-off-by: Antonio Borneo <antonio.borneo@foss.st.com> Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
141 lines
3.0 KiB
C
141 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* ARM Secure Monitor Call watchdog driver
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* Copyright (C) 2022, STMicroelectronics - All Rights Reserved
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* This file is based on Linux driver drivers/watchdog/arm_smc_wdt.c
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*/
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#define LOG_CATEGORY UCLASS_WDT
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#include <dm.h>
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#include <dm/device_compat.h>
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#include <linux/arm-smccc.h>
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#include <linux/psci.h>
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#include <wdt.h>
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#define DRV_NAME "arm_smc_wdt"
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#define WDT_TIMEOUT_SECS(TIMEOUT) ((TIMEOUT) / 1000)
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enum smcwd_call {
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SMCWD_INIT = 0,
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SMCWD_SET_TIMEOUT = 1,
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SMCWD_ENABLE = 2,
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SMCWD_PET = 3,
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SMCWD_GET_TIMELEFT = 4,
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};
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struct smcwd_priv_data {
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u32 smc_id;
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unsigned int min_timeout;
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unsigned int max_timeout;
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};
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static int smcwd_call(struct udevice *dev, enum smcwd_call call,
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unsigned long arg, struct arm_smccc_res *res)
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{
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struct smcwd_priv_data *priv = dev_get_priv(dev);
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struct arm_smccc_res local_res;
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if (!res)
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res = &local_res;
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arm_smccc_smc(priv->smc_id, call, arg, 0, 0, 0, 0, 0, res);
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if (res->a0 == PSCI_RET_NOT_SUPPORTED)
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return -ENODEV;
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if (res->a0 == PSCI_RET_INVALID_PARAMS)
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return -EINVAL;
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if (res->a0 == PSCI_RET_DISABLED)
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return -ENODATA;
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if (res->a0 != PSCI_RET_SUCCESS)
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return -EIO;
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return 0;
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}
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static int smcwd_reset(struct udevice *dev)
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{
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return smcwd_call(dev, SMCWD_PET, 0, NULL);
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}
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static int smcwd_stop(struct udevice *dev)
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{
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return smcwd_call(dev, SMCWD_ENABLE, 0, NULL);
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}
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static int smcwd_start(struct udevice *dev, u64 timeout_ms, ulong flags)
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{
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struct smcwd_priv_data *priv = dev_get_priv(dev);
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u64 timeout_sec = WDT_TIMEOUT_SECS(timeout_ms);
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int err;
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if (timeout_sec < priv->min_timeout || timeout_sec > priv->max_timeout) {
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dev_err(dev, "Timeout value not supported\n");
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return -EINVAL;
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}
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err = smcwd_call(dev, SMCWD_SET_TIMEOUT, timeout_sec, NULL);
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if (err) {
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dev_err(dev, "Timeout out configuration failed\n");
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return err;
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}
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return smcwd_call(dev, SMCWD_ENABLE, 1, NULL);
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}
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static int smcwd_probe(struct udevice *dev)
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{
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struct smcwd_priv_data *priv = dev_get_priv(dev);
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struct arm_smccc_res res;
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int err;
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priv->smc_id = dev_read_u32_default(dev, "arm,smc-id", 0x82003D06);
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err = smcwd_call(dev, SMCWD_INIT, 0, &res);
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if (err < 0) {
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dev_err(dev, "Init failed %i\n", err);
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return err;
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}
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priv->min_timeout = res.a1;
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priv->max_timeout = res.a2;
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/* If already started, then force u-boot to use it */
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err = smcwd_call(dev, SMCWD_GET_TIMELEFT, 0, NULL);
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switch (err) {
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case 0:
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dev_dbg(dev, "Already started\n");
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wdt_set_force_autostart(dev);
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break;
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case -ENODATA:
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dev_dbg(dev, "Not already started\n");
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break;
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default:
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/* Optional SMCWD_GET_TIMELEFT not implemented */
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break;
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}
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return 0;
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}
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static const struct wdt_ops smcwd_ops = {
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.start = smcwd_start,
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.stop = smcwd_stop,
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.reset = smcwd_reset,
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};
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static const struct udevice_id smcwd_dt_ids[] = {
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{ .compatible = "arm,smc-wdt" },
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{}
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};
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U_BOOT_DRIVER(wdt_sandbox) = {
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.name = "smcwd",
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.id = UCLASS_WDT,
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.of_match = smcwd_dt_ids,
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.priv_auto = sizeof(struct smcwd_priv_data),
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.probe = smcwd_probe,
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.ops = &smcwd_ops,
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};
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