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188 lines
4.2 KiB
188 lines
4.2 KiB
// 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 <[email protected]> |
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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 <[email protected]>"); |
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MODULE_DESCRIPTION("ARM Secure Monitor Call Watchdog Driver"); |
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MODULE_VERSION(DRV_VERSION);
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