337 lines · c
1// SPDX-License-Identifier: GPL-2.0+2 3/*4 * Driver for watchdog aspect of for Zodiac Inflight Innovations RAVE5 * Supervisory Processor(SP) MCU6 *7 * Copyright (C) 2017 Zodiac Inflight Innovation8 *9 */10 11#include <linux/delay.h>12#include <linux/kernel.h>13#include <linux/mfd/rave-sp.h>14#include <linux/module.h>15#include <linux/nvmem-consumer.h>16#include <linux/of.h>17#include <linux/platform_device.h>18#include <linux/reboot.h>19#include <linux/slab.h>20#include <linux/watchdog.h>21 22enum {23 RAVE_SP_RESET_BYTE = 1,24 RAVE_SP_RESET_REASON_NORMAL = 0,25 RAVE_SP_RESET_DELAY_MS = 500,26};27 28/**29 * struct rave_sp_wdt_variant - RAVE SP watchdog variant30 *31 * @max_timeout: Largest possible watchdog timeout setting32 * @min_timeout: Smallest possible watchdog timeout setting33 *34 * @configure: Function to send configuration command35 * @restart: Function to send "restart" command36 */37struct rave_sp_wdt_variant {38 unsigned int max_timeout;39 unsigned int min_timeout;40 41 int (*configure)(struct watchdog_device *, bool);42 int (*restart)(struct watchdog_device *);43};44 45/**46 * struct rave_sp_wdt - RAVE SP watchdog47 *48 * @wdd: Underlying watchdog device49 * @sp: Pointer to parent RAVE SP device50 * @variant: Device specific variant information51 * @reboot_notifier: Reboot notifier implementing machine reset52 */53struct rave_sp_wdt {54 struct watchdog_device wdd;55 struct rave_sp *sp;56 const struct rave_sp_wdt_variant *variant;57 struct notifier_block reboot_notifier;58};59 60static struct rave_sp_wdt *to_rave_sp_wdt(struct watchdog_device *wdd)61{62 return container_of(wdd, struct rave_sp_wdt, wdd);63}64 65static int rave_sp_wdt_exec(struct watchdog_device *wdd, void *data,66 size_t data_size)67{68 return rave_sp_exec(to_rave_sp_wdt(wdd)->sp,69 data, data_size, NULL, 0);70}71 72static int rave_sp_wdt_legacy_configure(struct watchdog_device *wdd, bool on)73{74 u8 cmd[] = {75 [0] = RAVE_SP_CMD_SW_WDT,76 [1] = 0,77 [2] = 0,78 [3] = on,79 [4] = on ? wdd->timeout : 0,80 };81 82 return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));83}84 85static int rave_sp_wdt_rdu_configure(struct watchdog_device *wdd, bool on)86{87 u8 cmd[] = {88 [0] = RAVE_SP_CMD_SW_WDT,89 [1] = 0,90 [2] = on,91 [3] = (u8)wdd->timeout,92 [4] = (u8)(wdd->timeout >> 8),93 };94 95 return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));96}97 98/**99 * rave_sp_wdt_configure - Configure watchdog device100 *101 * @wdd: Device to configure102 * @on: Desired state of the watchdog timer (ON/OFF)103 *104 * This function configures two aspects of the watchdog timer:105 *106 * - Wheither it is ON or OFF107 * - Its timeout duration108 *109 * with first aspect specified via function argument and second via110 * the value of 'wdd->timeout'.111 */112static int rave_sp_wdt_configure(struct watchdog_device *wdd, bool on)113{114 return to_rave_sp_wdt(wdd)->variant->configure(wdd, on);115}116 117static int rave_sp_wdt_legacy_restart(struct watchdog_device *wdd)118{119 u8 cmd[] = {120 [0] = RAVE_SP_CMD_RESET,121 [1] = 0,122 [2] = RAVE_SP_RESET_BYTE123 };124 125 return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));126}127 128static int rave_sp_wdt_rdu_restart(struct watchdog_device *wdd)129{130 u8 cmd[] = {131 [0] = RAVE_SP_CMD_RESET,132 [1] = 0,133 [2] = RAVE_SP_RESET_BYTE,134 [3] = RAVE_SP_RESET_REASON_NORMAL135 };136 137 return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));138}139 140static int rave_sp_wdt_reboot_notifier(struct notifier_block *nb,141 unsigned long action, void *data)142{143 /*144 * Restart handler is called in atomic context which means we145 * can't communicate to SP via UART. Luckily for use SP will146 * wait 500ms before actually resetting us, so we ask it to do147 * so here and let the rest of the system go on wrapping148 * things up.149 */150 if (action == SYS_DOWN || action == SYS_HALT) {151 struct rave_sp_wdt *sp_wd =152 container_of(nb, struct rave_sp_wdt, reboot_notifier);153 154 const int ret = sp_wd->variant->restart(&sp_wd->wdd);155 156 if (ret < 0)157 dev_err(sp_wd->wdd.parent,158 "Failed to issue restart command (%d)", ret);159 return NOTIFY_OK;160 }161 162 return NOTIFY_DONE;163}164 165static int rave_sp_wdt_restart(struct watchdog_device *wdd,166 unsigned long action, void *data)167{168 /*169 * The actual work was done by reboot notifier above. SP170 * firmware waits 500 ms before issuing reset, so let's hang171 * here for twice that delay and hopefuly we'd never reach172 * the return statement.173 */174 mdelay(2 * RAVE_SP_RESET_DELAY_MS);175 176 return -EIO;177}178 179static int rave_sp_wdt_start(struct watchdog_device *wdd)180{181 int ret;182 183 ret = rave_sp_wdt_configure(wdd, true);184 if (!ret)185 set_bit(WDOG_HW_RUNNING, &wdd->status);186 187 return ret;188}189 190static int rave_sp_wdt_stop(struct watchdog_device *wdd)191{192 return rave_sp_wdt_configure(wdd, false);193}194 195static int rave_sp_wdt_set_timeout(struct watchdog_device *wdd,196 unsigned int timeout)197{198 wdd->timeout = timeout;199 200 return rave_sp_wdt_configure(wdd, watchdog_active(wdd));201}202 203static int rave_sp_wdt_ping(struct watchdog_device *wdd)204{205 u8 cmd[] = {206 [0] = RAVE_SP_CMD_PET_WDT,207 [1] = 0,208 };209 210 return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd));211}212 213static const struct watchdog_info rave_sp_wdt_info = {214 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,215 .identity = "RAVE SP Watchdog",216};217 218static const struct watchdog_ops rave_sp_wdt_ops = {219 .owner = THIS_MODULE,220 .start = rave_sp_wdt_start,221 .stop = rave_sp_wdt_stop,222 .ping = rave_sp_wdt_ping,223 .set_timeout = rave_sp_wdt_set_timeout,224 .restart = rave_sp_wdt_restart,225};226 227static const struct rave_sp_wdt_variant rave_sp_wdt_legacy = {228 .max_timeout = 255,229 .min_timeout = 1,230 .configure = rave_sp_wdt_legacy_configure,231 .restart = rave_sp_wdt_legacy_restart,232};233 234static const struct rave_sp_wdt_variant rave_sp_wdt_rdu = {235 .max_timeout = 180,236 .min_timeout = 60,237 .configure = rave_sp_wdt_rdu_configure,238 .restart = rave_sp_wdt_rdu_restart,239};240 241static const struct of_device_id rave_sp_wdt_of_match[] = {242 {243 .compatible = "zii,rave-sp-watchdog-legacy",244 .data = &rave_sp_wdt_legacy,245 },246 {247 .compatible = "zii,rave-sp-watchdog",248 .data = &rave_sp_wdt_rdu,249 },250 { /* sentinel */ }251};252 253static int rave_sp_wdt_probe(struct platform_device *pdev)254{255 struct device *dev = &pdev->dev;256 struct watchdog_device *wdd;257 struct rave_sp_wdt *sp_wd;258 struct nvmem_cell *cell;259 __le16 timeout = 0;260 int ret;261 262 sp_wd = devm_kzalloc(dev, sizeof(*sp_wd), GFP_KERNEL);263 if (!sp_wd)264 return -ENOMEM;265 266 sp_wd->variant = of_device_get_match_data(dev);267 sp_wd->sp = dev_get_drvdata(dev->parent);268 269 wdd = &sp_wd->wdd;270 wdd->parent = dev;271 wdd->info = &rave_sp_wdt_info;272 wdd->ops = &rave_sp_wdt_ops;273 wdd->min_timeout = sp_wd->variant->min_timeout;274 wdd->max_timeout = sp_wd->variant->max_timeout;275 wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;276 wdd->timeout = 60;277 278 cell = nvmem_cell_get(dev, "wdt-timeout");279 if (!IS_ERR(cell)) {280 size_t len;281 void *value = nvmem_cell_read(cell, &len);282 283 if (!IS_ERR(value)) {284 memcpy(&timeout, value, min(len, sizeof(timeout)));285 kfree(value);286 }287 nvmem_cell_put(cell);288 }289 watchdog_init_timeout(wdd, le16_to_cpu(timeout), dev);290 watchdog_set_restart_priority(wdd, 255);291 watchdog_stop_on_unregister(wdd);292 293 sp_wd->reboot_notifier.notifier_call = rave_sp_wdt_reboot_notifier;294 ret = devm_register_reboot_notifier(dev, &sp_wd->reboot_notifier);295 if (ret) {296 dev_err(dev, "Failed to register reboot notifier\n");297 return ret;298 }299 300 /*301 * We don't know if watchdog is running now. To be sure, let's302 * start it and depend on watchdog core to ping it303 */304 wdd->max_hw_heartbeat_ms = wdd->max_timeout * 1000;305 ret = rave_sp_wdt_start(wdd);306 if (ret) {307 dev_err(dev, "Watchdog didn't start\n");308 return ret;309 }310 311 ret = devm_watchdog_register_device(dev, wdd);312 if (ret) {313 rave_sp_wdt_stop(wdd);314 return ret;315 }316 317 return 0;318}319 320static struct platform_driver rave_sp_wdt_driver = {321 .probe = rave_sp_wdt_probe,322 .driver = {323 .name = KBUILD_MODNAME,324 .of_match_table = rave_sp_wdt_of_match,325 },326};327 328module_platform_driver(rave_sp_wdt_driver);329 330MODULE_DEVICE_TABLE(of, rave_sp_wdt_of_match);331MODULE_LICENSE("GPL");332MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>");333MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>");334MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");335MODULE_DESCRIPTION("RAVE SP Watchdog driver");336MODULE_ALIAS("platform:rave-sp-watchdog");337