// SPDX-License-Identifier: GPL-2.0+ /* * Driver for watchdog aspect of for Zodiac Inflight Innovations RAVE * Supervisory Processor(SP) MCU * * Copyright (C) 2017 Zodiac Inflight Innovation * */ #include <linux/delay.h> #include <linux/kernel.h> #include <linux/mfd/rave-sp.h> #include <linux/module.h> #include <linux/nvmem-consumer.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/reboot.h> #include <linux/slab.h> #include <linux/watchdog.h> enum { RAVE_SP_RESET_BYTE = 1, RAVE_SP_RESET_REASON_NORMAL = 0, RAVE_SP_RESET_DELAY_MS = 500, }; /** * struct rave_sp_wdt_variant - RAVE SP watchdog variant * * @max_timeout: Largest possible watchdog timeout setting * @min_timeout: Smallest possible watchdog timeout setting * * @configure: Function to send configuration command * @restart: Function to send "restart" command */ struct rave_sp_wdt_variant { unsigned int max_timeout; unsigned int min_timeout; int (*configure)(struct watchdog_device *, bool); int (*restart)(struct watchdog_device *); }; /** * struct rave_sp_wdt - RAVE SP watchdog * * @wdd: Underlying watchdog device * @sp: Pointer to parent RAVE SP device * @variant: Device specific variant information * @reboot_notifier: Reboot notifier implementing machine reset */ struct rave_sp_wdt { struct watchdog_device wdd; struct rave_sp *sp; const struct rave_sp_wdt_variant *variant; struct notifier_block reboot_notifier; }; static struct rave_sp_wdt *to_rave_sp_wdt(struct watchdog_device *wdd) { return container_of(wdd, struct rave_sp_wdt, wdd); } static int rave_sp_wdt_exec(struct watchdog_device *wdd, void *data, size_t data_size) { return rave_sp_exec(to_rave_sp_wdt(wdd)->sp, data, data_size, NULL, 0); } static int rave_sp_wdt_legacy_configure(struct watchdog_device *wdd, bool on) { u8 cmd[] = { [0] = RAVE_SP_CMD_SW_WDT, [1] = 0, [2] = 0, [3] = on, [4] = on ? wdd->timeout : 0, }; return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); } static int rave_sp_wdt_rdu_configure(struct watchdog_device *wdd, bool on) { u8 cmd[] = { [0] = RAVE_SP_CMD_SW_WDT, [1] = 0, [2] = on, [3] = (u8)wdd->timeout, [4] = (u8)(wdd->timeout >> 8), }; return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); } /** * rave_sp_wdt_configure - Configure watchdog device * * @wdd: Device to configure * @on: Desired state of the watchdog timer (ON/OFF) * * This function configures two aspects of the watchdog timer: * * - Wheither it is ON or OFF * - Its timeout duration * * with first aspect specified via function argument and second via * the value of 'wdd->timeout'. */ static int rave_sp_wdt_configure(struct watchdog_device *wdd, bool on) { return to_rave_sp_wdt(wdd)->variant->configure(wdd, on); } static int rave_sp_wdt_legacy_restart(struct watchdog_device *wdd) { u8 cmd[] = { [0] = RAVE_SP_CMD_RESET, [1] = 0, [2] = RAVE_SP_RESET_BYTE }; return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); } static int rave_sp_wdt_rdu_restart(struct watchdog_device *wdd) { u8 cmd[] = { [0] = RAVE_SP_CMD_RESET, [1] = 0, [2] = RAVE_SP_RESET_BYTE, [3] = RAVE_SP_RESET_REASON_NORMAL }; return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); } static int rave_sp_wdt_reboot_notifier(struct notifier_block *nb, unsigned long action, void *data) { /* * Restart handler is called in atomic context which means we * can't communicate to SP via UART. Luckily for use SP will * wait 500ms before actually resetting us, so we ask it to do * so here and let the rest of the system go on wrapping * things up. */ if (action == SYS_DOWN || action == SYS_HALT) { struct rave_sp_wdt *sp_wd = container_of(nb, struct rave_sp_wdt, reboot_notifier); const int ret = sp_wd->variant->restart(&sp_wd->wdd); if (ret < 0) dev_err(sp_wd->wdd.parent, "Failed to issue restart command (%d)", ret); return NOTIFY_OK; } return NOTIFY_DONE; } static int rave_sp_wdt_restart(struct watchdog_device *wdd, unsigned long action, void *data) { /* * The actual work was done by reboot notifier above. SP * firmware waits 500 ms before issuing reset, so let's hang * here for twice that delay and hopefuly we'd never reach * the return statement. */ mdelay(2 * RAVE_SP_RESET_DELAY_MS); return -EIO; } static int rave_sp_wdt_start(struct watchdog_device *wdd) { int ret; ret = rave_sp_wdt_configure(wdd, true); if (!ret) set_bit(WDOG_HW_RUNNING, &wdd->status); return ret; } static int rave_sp_wdt_stop(struct watchdog_device *wdd) { return rave_sp_wdt_configure(wdd, false); } static int rave_sp_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout) { wdd->timeout = timeout; return rave_sp_wdt_configure(wdd, watchdog_active(wdd)); } static int rave_sp_wdt_ping(struct watchdog_device *wdd) { u8 cmd[] = { [0] = RAVE_SP_CMD_PET_WDT, [1] = 0, }; return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); } static const struct watchdog_info rave_sp_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .identity = "RAVE SP Watchdog", }; static const struct watchdog_ops rave_sp_wdt_ops = { .owner = THIS_MODULE, .start = rave_sp_wdt_start, .stop = rave_sp_wdt_stop, .ping = rave_sp_wdt_ping, .set_timeout = rave_sp_wdt_set_timeout, .restart = rave_sp_wdt_restart, }; static const struct rave_sp_wdt_variant rave_sp_wdt_legacy = { .max_timeout = 255, .min_timeout = 1, .configure = rave_sp_wdt_legacy_configure, .restart = rave_sp_wdt_legacy_restart, }; static const struct rave_sp_wdt_variant rave_sp_wdt_rdu = { .max_timeout = 180, .min_timeout = 60, .configure = rave_sp_wdt_rdu_configure, .restart = rave_sp_wdt_rdu_restart, }; static const struct of_device_id rave_sp_wdt_of_match[] = { { .compatible = "zii,rave-sp-watchdog-legacy", .data = &rave_sp_wdt_legacy, }, { .compatible = "zii,rave-sp-watchdog", .data = &rave_sp_wdt_rdu, }, { /* sentinel */ } }; static int rave_sp_wdt_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct watchdog_device *wdd; struct rave_sp_wdt *sp_wd; struct nvmem_cell *cell; __le16 timeout = 0; int ret; sp_wd = devm_kzalloc(dev, sizeof(*sp_wd), GFP_KERNEL); if (!sp_wd) return -ENOMEM; sp_wd->variant = of_device_get_match_data(dev); sp_wd->sp = dev_get_drvdata(dev->parent); wdd = &sp_wd->wdd; wdd->parent = dev; wdd->info = &rave_sp_wdt_info; wdd->ops = &rave_sp_wdt_ops; wdd->min_timeout = sp_wd->variant->min_timeout; wdd->max_timeout = sp_wd->variant->max_timeout; wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS; wdd->timeout = 60; cell = nvmem_cell_get(dev, "wdt-timeout"); if (!IS_ERR(cell)) { size_t len; void *value = nvmem_cell_read(cell, &len); if (!IS_ERR(value)) { memcpy(&timeout, value, min(len, sizeof(timeout))); kfree(value); } nvmem_cell_put(cell); } watchdog_init_timeout(wdd, le16_to_cpu(timeout), dev); watchdog_set_restart_priority(wdd, 255); watchdog_stop_on_unregister(wdd); sp_wd->reboot_notifier.notifier_call = rave_sp_wdt_reboot_notifier; ret = devm_register_reboot_notifier(dev, &sp_wd->reboot_notifier); if (ret) { dev_err(dev, "Failed to register reboot notifier\n"); return ret; } /* * We don't know if watchdog is running now. To be sure, let's * start it and depend on watchdog core to ping it */ wdd->max_hw_heartbeat_ms = wdd->max_timeout * 1000; ret = rave_sp_wdt_start(wdd); if (ret) { dev_err(dev, "Watchdog didn't start\n"); return ret; } ret = devm_watchdog_register_device(dev, wdd); if (ret) { rave_sp_wdt_stop(wdd); return ret; } return 0; } static struct platform_driver rave_sp_wdt_driver = { .probe = rave_sp_wdt_probe, .driver = { .name = KBUILD_MODNAME, .of_match_table = rave_sp_wdt_of_match, }, }; module_platform_driver(rave_sp_wdt_driver); MODULE_DEVICE_TABLE(of, rave_sp_wdt_of_match); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>"); MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>"); MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>"); MODULE_DESCRIPTION("RAVE SP Watchdog driver"); MODULE_ALIAS("platform:rave-sp-watchdog");