Neeraj Upadhyay | d983a64 | 2018-08-20 14:22:48 +0530 | [diff] [blame] | 1 | /* Copyright (c) 2018, The Linux Foundation. All rights reserved. |
| 2 | * |
| 3 | * This program is free software; you can redistribute it and/or modify |
| 4 | * it under the terms of the GNU General Public License version 2 and |
| 5 | * only version 2 as published by the Free Software Foundation. |
| 6 | * |
| 7 | * This program is distributed in the hope that it will be useful, |
| 8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 10 | * GNU General Public License for more details. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/cpu.h> |
| 14 | #include <linux/delay.h> |
| 15 | #include <linux/io.h> |
| 16 | #include <linux/interrupt.h> |
| 17 | #include <linux/irq.h> |
| 18 | #include <linux/kernel.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/of.h> |
| 21 | #include <linux/kthread.h> |
| 22 | #include <linux/platform_device.h> |
| 23 | #include <linux/slab.h> |
| 24 | #include <linux/wait.h> |
| 25 | #include <linux/watchdog.h> |
| 26 | #include <linux/of_device.h> |
| 27 | |
| 28 | #define MASK_SIZE 32 |
| 29 | #define QCOM_VM_WDT_HZ 32765 |
| 30 | #define QCOM_VM_PET_TIMEOUT 9U |
| 31 | #define QCOM_VM_BARK_TIMEOUT 11U |
| 32 | |
| 33 | enum qcom_vm_wdt_reg { |
| 34 | WDT_RST, |
| 35 | WDT_CTRL, |
| 36 | WDT_STS, |
| 37 | WDT_BARK_TIME, |
| 38 | WDT_BITE_TIME, |
| 39 | }; |
| 40 | |
| 41 | static const u32 qcom_vm_wdt_reg_offset_data[] = { |
| 42 | [WDT_RST] = 0x4, |
| 43 | [WDT_CTRL] = 0x8, |
| 44 | [WDT_STS] = 0xC, |
| 45 | [WDT_BARK_TIME] = 0x10, |
| 46 | [WDT_BITE_TIME] = 0x14, |
| 47 | }; |
| 48 | |
| 49 | struct qcom_vm_wdt { |
| 50 | struct watchdog_device wdd; |
| 51 | void __iomem *base; |
| 52 | const u32 *layout; |
| 53 | unsigned int bark_irq; |
| 54 | unsigned int bite_irq; |
| 55 | unsigned int bark_time; |
| 56 | unsigned int pet_time; |
| 57 | unsigned long long last_pet; |
| 58 | struct device *dev; |
| 59 | struct notifier_block panic_blk; |
| 60 | struct timer_list pet_timer; |
| 61 | bool timer_expired; |
| 62 | wait_queue_head_t pet_complete; |
| 63 | struct task_struct *watchdog_task; |
| 64 | cpumask_t alive_mask; |
| 65 | struct mutex disable_lock; |
| 66 | }; |
| 67 | |
| 68 | static int enable = 1; |
| 69 | module_param(enable, int, 0000); |
| 70 | |
| 71 | /* Disable the watchdog in hypervisor */ |
| 72 | static int hyp_enable = 1; |
| 73 | module_param(hyp_enable, int, 0000); |
| 74 | |
| 75 | static void __iomem *qcom_vm_wdt_addr(struct qcom_vm_wdt *wdt, |
| 76 | enum qcom_vm_wdt_reg reg) |
| 77 | { |
| 78 | return wdt->base + wdt->layout[reg]; |
| 79 | } |
| 80 | |
| 81 | static void dump_cpu_alive_mask(struct qcom_vm_wdt *wdt) |
| 82 | { |
| 83 | static char alive_mask_buf[MASK_SIZE]; |
| 84 | |
| 85 | scnprintf(alive_mask_buf, MASK_SIZE, "%*pb1", cpumask_pr_args( |
| 86 | &wdt->alive_mask)); |
| 87 | dev_info(wdt->dev, "cpu alive mask from last pet %s\n", |
| 88 | alive_mask_buf); |
| 89 | } |
| 90 | |
| 91 | static irqreturn_t qcom_vm_wdt_bark_handler(int irq, void *dev_id) |
| 92 | { |
| 93 | struct qcom_vm_wdt *wdt = (struct qcom_vm_wdt *)dev_id; |
| 94 | unsigned long long t = sched_clock(); |
| 95 | |
| 96 | dev_info(wdt->dev, "Watchdog bark! Now = %lu\n", |
| 97 | (unsigned long) t); |
| 98 | dev_info(wdt->dev, "Watchdog last pet at %lu\n", |
| 99 | (unsigned long) wdt->last_pet); |
| 100 | dump_cpu_alive_mask(wdt); |
| 101 | pr_info("Causing a watchdog bite!"); |
| 102 | __raw_writel(1 * QCOM_VM_WDT_HZ, qcom_vm_wdt_addr(wdt, WDT_BITE_TIME)); |
| 103 | /* Make sure bite time is written before we reset */ |
| 104 | mb(); |
| 105 | __raw_writel(1, qcom_vm_wdt_addr(wdt, WDT_RST)); |
| 106 | /* Make sure we wait only after reset */ |
| 107 | mb(); |
| 108 | /* Delay to make sure bite occurs */ |
| 109 | msleep(10000); |
| 110 | |
| 111 | panic("Failed to cause a watchdog bite! - Falling back to kernel panic!"); |
| 112 | return IRQ_HANDLED; |
| 113 | } |
| 114 | |
| 115 | static int qcom_vm_wdt_suspend(struct device *dev) |
| 116 | { |
| 117 | struct qcom_vm_wdt *wdt = |
| 118 | (struct qcom_vm_wdt *)dev_get_drvdata(dev); |
| 119 | |
| 120 | if (!enable) |
| 121 | return 0; |
| 122 | |
| 123 | __raw_writel(1, qcom_vm_wdt_addr(wdt, WDT_RST)); |
| 124 | /* Make sure watchdog is suspended before setting enable */ |
| 125 | mb(); |
| 126 | |
| 127 | wdt->last_pet = sched_clock(); |
| 128 | return 0; |
| 129 | } |
| 130 | |
| 131 | static int qcom_vm_wdt_resume(struct device *dev) |
| 132 | { |
| 133 | struct qcom_vm_wdt *wdt = |
| 134 | (struct qcom_vm_wdt *)dev_get_drvdata(dev); |
| 135 | |
| 136 | if (!enable) |
| 137 | return 0; |
| 138 | |
| 139 | __raw_writel(1, qcom_vm_wdt_addr(wdt, WDT_RST)); |
| 140 | /* Make sure watchdog is suspended before setting enable */ |
| 141 | mb(); |
| 142 | |
| 143 | wdt->last_pet = sched_clock(); |
| 144 | return 0; |
| 145 | } |
| 146 | |
| 147 | static int qcom_vm_wdt_panic_handler(struct notifier_block *this, |
| 148 | unsigned long event, void *ptr) |
| 149 | { |
| 150 | struct qcom_vm_wdt *wdt = container_of(this, struct qcom_vm_wdt, |
| 151 | panic_blk); |
| 152 | |
| 153 | __raw_writel(QCOM_VM_WDT_HZ * (panic_timeout + 10), |
| 154 | qcom_vm_wdt_addr(wdt, WDT_BARK_TIME)); |
| 155 | __raw_writel(QCOM_VM_WDT_HZ * (panic_timeout + 10), |
| 156 | qcom_vm_wdt_addr(wdt, WDT_BITE_TIME)); |
| 157 | __raw_writel(1, qcom_vm_wdt_addr(wdt, WDT_RST)); |
| 158 | /* |
| 159 | * Ensure that bark, bite times, and reset is done, before |
| 160 | * moving forward. |
| 161 | */ |
| 162 | mb(); |
| 163 | |
| 164 | return NOTIFY_DONE; |
| 165 | } |
| 166 | |
| 167 | static void qcom_vm_wdt_disable(struct qcom_vm_wdt *wdt) |
| 168 | { |
| 169 | if (hyp_enable == 1) |
| 170 | __raw_writel(0, qcom_vm_wdt_addr(wdt, WDT_CTRL)); |
| 171 | /* Make sure watchdog is disabled before proceeding */ |
| 172 | mb(); |
| 173 | devm_free_irq(wdt->dev, wdt->bark_irq, wdt); |
| 174 | enable = 0; |
| 175 | /*Ensure all cpus see update to enable*/ |
| 176 | smp_mb(); |
| 177 | atomic_notifier_chain_unregister(&panic_notifier_list, |
| 178 | &wdt->panic_blk); |
| 179 | del_timer_sync(&wdt->pet_timer); |
| 180 | /* may be suspended after the first write above */ |
| 181 | if (hyp_enable == 1) |
| 182 | __raw_writel(0, qcom_vm_wdt_addr(wdt, WDT_CTRL)); |
| 183 | /* Make sure watchdog is disabled before setting enable */ |
| 184 | mb(); |
| 185 | pr_info("QCOM VM Watchdog deactivated.\n"); |
| 186 | } |
| 187 | |
| 188 | static ssize_t qcom_vm_wdt_disable_get(struct device *dev, |
| 189 | struct device_attribute *attr, char *buf) |
| 190 | { |
| 191 | int ret; |
| 192 | struct qcom_vm_wdt *wdt = dev_get_drvdata(dev); |
| 193 | |
| 194 | mutex_lock(&wdt->disable_lock); |
| 195 | ret = snprintf(buf, PAGE_SIZE, "%d\n", enable == 0 ? 1 : 0); |
| 196 | mutex_unlock(&wdt->disable_lock); |
| 197 | return ret; |
| 198 | } |
| 199 | |
| 200 | static ssize_t qcom_vm_wdt_disable_set(struct device *dev, |
| 201 | struct device_attribute *attr, |
| 202 | const char *buf, size_t count) |
| 203 | { |
| 204 | int ret; |
| 205 | u8 disable; |
| 206 | struct qcom_vm_wdt *wdt = dev_get_drvdata(dev); |
| 207 | |
| 208 | ret = kstrtou8(buf, 10, &disable); |
| 209 | if (ret) { |
| 210 | dev_err(wdt->dev, "invalid user input\n"); |
| 211 | return ret; |
| 212 | } |
| 213 | if (disable == 1) { |
| 214 | mutex_lock(&wdt->disable_lock); |
| 215 | if (enable == 0) { |
| 216 | pr_info("QCOM VM Watchdog already disabled\n"); |
| 217 | mutex_unlock(&wdt->disable_lock); |
| 218 | return count; |
| 219 | } |
| 220 | qcom_vm_wdt_disable(wdt); |
| 221 | mutex_unlock(&wdt->disable_lock); |
| 222 | } else { |
| 223 | pr_err("invalid operation, only disable = 1 supported\n"); |
| 224 | return -EINVAL; |
| 225 | } |
| 226 | return count; |
| 227 | } |
| 228 | |
| 229 | static DEVICE_ATTR(disable, 0600, qcom_vm_wdt_disable_get, |
| 230 | qcom_vm_wdt_disable_set); |
| 231 | |
| 232 | static void qcom_vm_wdt_hyp_disable(struct qcom_vm_wdt *wdt) |
| 233 | { |
| 234 | __raw_writel(1 << 2, qcom_vm_wdt_addr(wdt, WDT_CTRL)); |
| 235 | hyp_enable = 0; |
| 236 | } |
| 237 | |
| 238 | static ssize_t qcom_vm_wdt_hyp_disable_get(struct device *dev, |
| 239 | struct device_attribute *attr, char *buf) |
| 240 | { |
| 241 | int ret; |
| 242 | struct qcom_vm_wdt *wdt = dev_get_drvdata(dev); |
| 243 | |
| 244 | mutex_lock(&wdt->disable_lock); |
| 245 | ret = snprintf(buf, PAGE_SIZE, "%d\n", hyp_enable == 0 ? 1 : 0); |
| 246 | mutex_unlock(&wdt->disable_lock); |
| 247 | return ret; |
| 248 | } |
| 249 | |
| 250 | static ssize_t qcom_vm_wdt_hyp_disable_set(struct device *dev, |
| 251 | struct device_attribute *attr, |
| 252 | const char *buf, size_t count) |
| 253 | { |
| 254 | int ret; |
| 255 | u8 disable; |
| 256 | struct qcom_vm_wdt *wdt = dev_get_drvdata(dev); |
| 257 | |
| 258 | ret = kstrtou8(buf, 10, &disable); |
| 259 | if (ret) { |
| 260 | dev_err(wdt->dev, "invalid user input\n"); |
| 261 | return ret; |
| 262 | } |
| 263 | if (disable == 1) { |
| 264 | mutex_lock(&wdt->disable_lock); |
| 265 | if (hyp_enable == 0) { |
| 266 | pr_info("QCOM VM Watchdog already disabled in Hyp\n"); |
| 267 | mutex_unlock(&wdt->disable_lock); |
| 268 | return count; |
| 269 | } |
| 270 | qcom_vm_wdt_hyp_disable(wdt); |
| 271 | mutex_unlock(&wdt->disable_lock); |
| 272 | } else { |
| 273 | pr_err("invalid operation, only hyp_disable = 1 supported\n"); |
| 274 | return -EINVAL; |
| 275 | } |
| 276 | return count; |
| 277 | } |
| 278 | |
| 279 | static DEVICE_ATTR(hyp_disable, 0600, qcom_vm_wdt_hyp_disable_get, |
| 280 | qcom_vm_wdt_hyp_disable_set); |
| 281 | |
| 282 | static int qcom_vm_wdt_start(struct qcom_vm_wdt *wdt) |
| 283 | { |
| 284 | __raw_writel(0, qcom_vm_wdt_addr(wdt, WDT_CTRL)); |
| 285 | __raw_writel(1, qcom_vm_wdt_addr(wdt, WDT_RST)); |
| 286 | __raw_writel((wdt->bark_time / 1000) * QCOM_VM_WDT_HZ, |
| 287 | qcom_vm_wdt_addr(wdt, WDT_BARK_TIME)); |
| 288 | __raw_writel((wdt->bark_time / 1000 + 3) * QCOM_VM_WDT_HZ, |
| 289 | qcom_vm_wdt_addr(wdt, WDT_BITE_TIME)); |
| 290 | __raw_writel(1, qcom_vm_wdt_addr(wdt, WDT_CTRL)); |
| 291 | return 0; |
| 292 | } |
| 293 | |
| 294 | static void keep_alive_response(void *info) |
| 295 | { |
| 296 | int cpu = smp_processor_id(); |
| 297 | struct qcom_vm_wdt *wdt = (struct qcom_vm_wdt *)info; |
| 298 | |
| 299 | cpumask_set_cpu(cpu, &wdt->alive_mask); |
| 300 | /* Make sure alive mask is cleared and set in order */ |
| 301 | smp_mb(); |
| 302 | } |
| 303 | |
| 304 | static int qcom_vm_wdt_ping(struct qcom_vm_wdt *wdt) |
| 305 | { |
| 306 | int cpu; |
| 307 | |
| 308 | cpumask_clear(&wdt->alive_mask); |
| 309 | for_each_cpu(cpu, cpu_online_mask) { |
| 310 | smp_call_function_single(cpu, keep_alive_response, wdt, 1); |
| 311 | } |
| 312 | __raw_writel(1, qcom_vm_wdt_addr(wdt, WDT_RST)); |
| 313 | wdt->last_pet = sched_clock(); |
| 314 | return 0; |
| 315 | } |
| 316 | |
| 317 | static void vm_pet_task_wakeup(unsigned long data) |
| 318 | { |
| 319 | struct qcom_vm_wdt *wdt = (struct qcom_vm_wdt *)data; |
| 320 | |
| 321 | wdt->timer_expired = true; |
| 322 | wake_up(&wdt->pet_complete); |
| 323 | } |
| 324 | |
| 325 | static __ref int vm_watchdog_kthread(void *arg) |
| 326 | { |
| 327 | struct qcom_vm_wdt *wdt = (struct qcom_vm_wdt *)arg; |
| 328 | |
| 329 | while (!kthread_should_stop()) { |
| 330 | while (wait_event_interruptible( |
| 331 | wdt->pet_complete, |
| 332 | wdt->timer_expired) != 0) |
| 333 | ; |
| 334 | if (enable) |
| 335 | qcom_vm_wdt_ping(wdt); |
| 336 | wdt->timer_expired = false; |
| 337 | mod_timer(&wdt->pet_timer, jiffies + |
| 338 | msecs_to_jiffies(wdt->pet_time)); |
| 339 | } |
| 340 | return 0; |
| 341 | } |
| 342 | |
| 343 | static int qcom_vm_wdt_probe(struct platform_device *pdev) |
| 344 | { |
| 345 | struct qcom_vm_wdt *wdt; |
| 346 | struct resource *res; |
| 347 | const u32 *regs; |
| 348 | int ret, error; |
| 349 | |
| 350 | if (!pdev->dev.of_node || !enable) |
| 351 | return -ENODEV; |
| 352 | |
| 353 | regs = of_device_get_match_data(&pdev->dev); |
| 354 | if (!regs) { |
| 355 | dev_err(&pdev->dev, "Unsupported QCOM WDT module\n"); |
| 356 | return -ENODEV; |
| 357 | } |
| 358 | |
| 359 | wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); |
| 360 | if (!wdt) |
| 361 | return -ENOMEM; |
| 362 | |
| 363 | res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "wdt-base"); |
| 364 | if (!res) { |
| 365 | ret = -ENODEV; |
| 366 | goto err; |
| 367 | } |
| 368 | |
| 369 | wdt->base = devm_ioremap_resource(&pdev->dev, res); |
| 370 | if (IS_ERR(wdt->base)) { |
| 371 | ret = PTR_ERR(wdt->base); |
| 372 | goto err; |
| 373 | } |
| 374 | |
| 375 | wdt->layout = regs; |
| 376 | wdt->dev = &pdev->dev; |
| 377 | |
| 378 | wdt->bark_irq = platform_get_irq(pdev, 0); |
| 379 | wdt->bite_irq = platform_get_irq(pdev, 1); |
| 380 | wdt->last_pet = sched_clock(); |
| 381 | |
| 382 | ret = of_property_read_u32(pdev->dev.of_node, "qcom,bark-time", |
| 383 | &wdt->bark_time); |
| 384 | if (ret) |
| 385 | wdt->bark_time = QCOM_VM_BARK_TIMEOUT * 1000; |
| 386 | ret = of_property_read_u32(pdev->dev.of_node, "qcom,pet-time", |
| 387 | &wdt->pet_time); |
| 388 | if (ret) |
| 389 | wdt->pet_time = QCOM_VM_PET_TIMEOUT * 1000; |
| 390 | |
| 391 | wdt->watchdog_task = kthread_create(vm_watchdog_kthread, wdt, |
| 392 | "qcom_vm_watchdog"); |
| 393 | if (IS_ERR(wdt->watchdog_task)) { |
| 394 | ret = PTR_ERR(wdt->watchdog_task); |
| 395 | goto err; |
| 396 | } |
| 397 | |
| 398 | init_waitqueue_head(&wdt->pet_complete); |
| 399 | wdt->timer_expired = false; |
| 400 | wake_up_process(wdt->watchdog_task); |
| 401 | init_timer(&wdt->pet_timer); |
| 402 | wdt->pet_timer.data = (unsigned long)wdt; |
| 403 | wdt->pet_timer.function = vm_pet_task_wakeup; |
| 404 | wdt->pet_timer.expires = jiffies + |
| 405 | msecs_to_jiffies(wdt->pet_time); |
| 406 | add_timer(&wdt->pet_timer); |
| 407 | cpumask_clear(&wdt->alive_mask); |
| 408 | |
| 409 | wdt->panic_blk.notifier_call = qcom_vm_wdt_panic_handler; |
| 410 | atomic_notifier_chain_register(&panic_notifier_list, &wdt->panic_blk); |
| 411 | |
| 412 | platform_set_drvdata(pdev, wdt); |
| 413 | mutex_init(&wdt->disable_lock); |
| 414 | |
| 415 | error = device_create_file(wdt->dev, &dev_attr_disable); |
| 416 | error |= device_create_file(wdt->dev, &dev_attr_hyp_disable); |
| 417 | |
| 418 | if (error) |
| 419 | dev_err(wdt->dev, "cannot create sysfs attribute\n"); |
| 420 | |
| 421 | qcom_vm_wdt_start(wdt); |
| 422 | ret = devm_request_irq(&pdev->dev, wdt->bark_irq, |
| 423 | qcom_vm_wdt_bark_handler, IRQF_TRIGGER_RISING, |
| 424 | "apps_wdog_bark", wdt); |
| 425 | |
| 426 | if (hyp_enable == 0) |
| 427 | qcom_vm_wdt_hyp_disable(wdt); |
| 428 | return 0; |
| 429 | |
| 430 | err: |
| 431 | kfree(wdt); |
| 432 | return ret; |
| 433 | } |
| 434 | |
| 435 | static int qcom_vm_wdt_remove(struct platform_device *pdev) |
| 436 | { |
| 437 | struct qcom_vm_wdt *wdt = platform_get_drvdata(pdev); |
| 438 | |
| 439 | mutex_lock(&wdt->disable_lock); |
| 440 | if (enable) |
| 441 | qcom_vm_wdt_disable(wdt); |
| 442 | mutex_unlock(&wdt->disable_lock); |
| 443 | device_remove_file(wdt->dev, &dev_attr_disable); |
| 444 | device_remove_file(wdt->dev, &dev_attr_hyp_disable); |
| 445 | dev_info(wdt->dev, "QCOM VM Watchdog Exit - Deactivated\n"); |
| 446 | del_timer_sync(&wdt->pet_timer); |
| 447 | kthread_stop(wdt->watchdog_task); |
| 448 | kfree(wdt); |
| 449 | return 0; |
| 450 | } |
| 451 | |
| 452 | static const struct of_device_id qcom_vm_wdt_of_table[] = { |
| 453 | { .compatible = "qcom,vm-wdt", .data = qcom_vm_wdt_reg_offset_data }, |
| 454 | { }, |
| 455 | }; |
| 456 | MODULE_DEVICE_TABLE(of, qcom_wdt_of_table); |
| 457 | |
| 458 | static const struct dev_pm_ops qcom_vm_wdt_dev_pm_ops = { |
| 459 | .suspend_noirq = qcom_vm_wdt_suspend, |
| 460 | .resume_noirq = qcom_vm_wdt_resume, |
| 461 | }; |
| 462 | |
| 463 | static struct platform_driver qcom_vm_watchdog_driver = { |
| 464 | .probe = qcom_vm_wdt_probe, |
| 465 | .remove = qcom_vm_wdt_remove, |
| 466 | .driver = { |
| 467 | .name = KBUILD_MODNAME, |
| 468 | .pm = &qcom_vm_wdt_dev_pm_ops, |
| 469 | .of_match_table = qcom_vm_wdt_of_table, |
| 470 | }, |
| 471 | }; |
| 472 | module_platform_driver(qcom_vm_watchdog_driver); |
| 473 | |
| 474 | MODULE_DESCRIPTION("QCOM VM Watchdog Driver"); |
| 475 | MODULE_LICENSE("GPL v2"); |