Andrey Smirnov | c3bb333 | 2017-12-20 22:51:17 -0800 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | |
| 3 | /* |
| 4 | * Driver for watchdog aspect of for Zodiac Inflight Innovations RAVE |
| 5 | * Supervisory Processor(SP) MCU |
| 6 | * |
| 7 | * Copyright (C) 2017 Zodiac Inflight Innovation |
| 8 | * |
| 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_device.h> |
| 17 | #include <linux/platform_device.h> |
| 18 | #include <linux/reboot.h> |
| 19 | #include <linux/slab.h> |
| 20 | #include <linux/watchdog.h> |
| 21 | |
| 22 | enum { |
| 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 variant |
| 30 | * |
| 31 | * @max_timeout: Largest possible watchdog timeout setting |
| 32 | * @min_timeout: Smallest possible watchdog timeout setting |
| 33 | * |
| 34 | * @configure: Function to send configuration command |
| 35 | * @restart: Function to send "restart" command |
| 36 | */ |
| 37 | struct 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 watchdog |
| 47 | * |
| 48 | * @wdd: Underlying watchdog device |
| 49 | * @sp: Pointer to parent RAVE SP device |
| 50 | * @variant: Device specific variant information |
| 51 | * @reboot_notifier: Reboot notifier implementing machine reset |
| 52 | */ |
| 53 | struct 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 | |
| 60 | static 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 | |
| 65 | static 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 | |
| 72 | static 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 | |
| 85 | static 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 device |
| 100 | * |
| 101 | * @wdd: Device to configure |
| 102 | * @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 OFF |
| 107 | * - Its timeout duration |
| 108 | * |
| 109 | * with first aspect specified via function argument and second via |
| 110 | * the value of 'wdd->timeout'. |
| 111 | */ |
| 112 | static 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 | |
| 117 | static 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_BYTE |
| 123 | }; |
| 124 | |
| 125 | return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); |
| 126 | } |
| 127 | |
| 128 | static 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_NORMAL |
| 135 | }; |
| 136 | |
| 137 | return rave_sp_wdt_exec(wdd, cmd, sizeof(cmd)); |
| 138 | } |
| 139 | |
| 140 | static 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 we |
| 145 | * can't communicate to SP via UART. Luckily for use SP will |
| 146 | * wait 500ms before actually resetting us, so we ask it to do |
| 147 | * so here and let the rest of the system go on wrapping |
| 148 | * 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 | |
| 165 | static 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. SP |
| 170 | * firmware waits 500 ms before issuing reset, so let's hang |
| 171 | * here for twice that delay and hopefuly we'd never reach |
| 172 | * the return statement. |
| 173 | */ |
| 174 | mdelay(2 * RAVE_SP_RESET_DELAY_MS); |
| 175 | |
| 176 | return -EIO; |
| 177 | } |
| 178 | |
| 179 | static 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 | |
| 190 | static int rave_sp_wdt_stop(struct watchdog_device *wdd) |
| 191 | { |
| 192 | return rave_sp_wdt_configure(wdd, false); |
| 193 | } |
| 194 | |
| 195 | static 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 | |
| 203 | static 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 | |
| 213 | static const struct watchdog_info rave_sp_wdt_info = { |
| 214 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
| 215 | .identity = "RAVE SP Watchdog", |
| 216 | }; |
| 217 | |
| 218 | static 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 | |
| 227 | static 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 | |
| 234 | static 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 | |
| 241 | static 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 | |
| 253 | static 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's |
| 302 | * start it and depend on watchdog core to ping it |
| 303 | */ |
| 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) { |
Andrey Smirnov | c3bb333 | 2017-12-20 22:51:17 -0800 | [diff] [blame] | 313 | rave_sp_wdt_stop(wdd); |
| 314 | return ret; |
| 315 | } |
| 316 | |
| 317 | return 0; |
| 318 | } |
| 319 | |
| 320 | static 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 | |
| 328 | module_platform_driver(rave_sp_wdt_driver); |
| 329 | |
| 330 | MODULE_DEVICE_TABLE(of, rave_sp_wdt_of_match); |
| 331 | MODULE_LICENSE("GPL"); |
| 332 | MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>"); |
| 333 | MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>"); |
| 334 | MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>"); |
| 335 | MODULE_DESCRIPTION("RAVE SP Watchdog driver"); |
| 336 | MODULE_ALIAS("platform:rave-sp-watchdog"); |