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189 lines
4.2 KiB
C
189 lines
4.2 KiB
C
![]() |
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ARM Secure Monitor Call watchdog driver
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*
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* Copyright 2020 Google LLC.
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* Julius Werner <jwerner@chromium.org>
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* Based on mtk_wdt.c
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*/
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#include <linux/arm-smccc.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/types.h>
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#include <linux/watchdog.h>
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#include <uapi/linux/psci.h>
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#define DRV_NAME "arm_smc_wdt"
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#define DRV_VERSION "1.0"
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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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static bool nowayout = WATCHDOG_NOWAYOUT;
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static unsigned int timeout;
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static int smcwd_call(struct watchdog_device *wdd, 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 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((u32)(uintptr_t)watchdog_get_drvdata(wdd), call, arg, 0,
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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_SUCCESS)
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return -EIO;
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return 0;
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}
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static int smcwd_ping(struct watchdog_device *wdd)
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{
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return smcwd_call(wdd, SMCWD_PET, 0, NULL);
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}
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static unsigned int smcwd_get_timeleft(struct watchdog_device *wdd)
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{
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struct arm_smccc_res res;
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smcwd_call(wdd, SMCWD_GET_TIMELEFT, 0, &res);
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if (res.a0)
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return 0;
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return res.a1;
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}
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static int smcwd_set_timeout(struct watchdog_device *wdd, unsigned int timeout)
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{
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int res;
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res = smcwd_call(wdd, SMCWD_SET_TIMEOUT, timeout, NULL);
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if (!res)
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wdd->timeout = timeout;
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return res;
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}
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static int smcwd_stop(struct watchdog_device *wdd)
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{
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return smcwd_call(wdd, SMCWD_ENABLE, 0, NULL);
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}
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static int smcwd_start(struct watchdog_device *wdd)
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{
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return smcwd_call(wdd, SMCWD_ENABLE, 1, NULL);
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}
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static const struct watchdog_info smcwd_info = {
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.identity = DRV_NAME,
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.options = WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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};
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static const struct watchdog_ops smcwd_ops = {
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.start = smcwd_start,
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.stop = smcwd_stop,
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.ping = smcwd_ping,
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.set_timeout = smcwd_set_timeout,
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};
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static const struct watchdog_ops smcwd_timeleft_ops = {
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.start = smcwd_start,
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.stop = smcwd_stop,
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.ping = smcwd_ping,
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.set_timeout = smcwd_set_timeout,
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.get_timeleft = smcwd_get_timeleft,
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};
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static int smcwd_probe(struct platform_device *pdev)
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{
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struct watchdog_device *wdd;
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int err;
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struct arm_smccc_res res;
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u32 smc_func_id;
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wdd = devm_kzalloc(&pdev->dev, sizeof(*wdd), GFP_KERNEL);
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if (!wdd)
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return -ENOMEM;
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platform_set_drvdata(pdev, wdd);
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if (of_property_read_u32(pdev->dev.of_node, "arm,smc-id",
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&smc_func_id))
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smc_func_id = 0x82003D06;
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watchdog_set_drvdata(wdd, (void *)(uintptr_t)smc_func_id);
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err = smcwd_call(wdd, SMCWD_INIT, 0, &res);
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if (err < 0)
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return err;
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wdd->info = &smcwd_info;
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/* get_timeleft is optional */
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if (smcwd_call(wdd, SMCWD_GET_TIMELEFT, 0, NULL))
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wdd->ops = &smcwd_ops;
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else
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wdd->ops = &smcwd_timeleft_ops;
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wdd->timeout = res.a2;
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wdd->max_timeout = res.a2;
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wdd->min_timeout = res.a1;
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wdd->parent = &pdev->dev;
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watchdog_stop_on_reboot(wdd);
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watchdog_stop_on_unregister(wdd);
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watchdog_set_nowayout(wdd, nowayout);
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watchdog_init_timeout(wdd, timeout, &pdev->dev);
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err = smcwd_set_timeout(wdd, wdd->timeout);
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if (err)
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return err;
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err = devm_watchdog_register_device(&pdev->dev, wdd);
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if (err)
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return err;
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dev_info(&pdev->dev,
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"Watchdog registered (timeout=%d sec, nowayout=%d)\n",
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wdd->timeout, nowayout);
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return 0;
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}
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static const struct of_device_id smcwd_dt_ids[] = {
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{ .compatible = "arm,smc-wdt" },
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{}
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};
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MODULE_DEVICE_TABLE(of, smcwd_dt_ids);
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static struct platform_driver smcwd_driver = {
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.probe = smcwd_probe,
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.driver = {
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.name = DRV_NAME,
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.of_match_table = smcwd_dt_ids,
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},
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};
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module_platform_driver(smcwd_driver);
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module_param(timeout, uint, 0);
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MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Julius Werner <jwerner@chromium.org>");
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MODULE_DESCRIPTION("ARM Secure Monitor Call Watchdog Driver");
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MODULE_VERSION(DRV_VERSION);
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