octeon-wdt-main.c 19 KB

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  1. /*
  2. * Octeon Watchdog driver
  3. *
  4. * Copyright (C) 2007, 2008, 2009, 2010 Cavium Networks
  5. *
  6. * Some parts derived from wdt.c
  7. *
  8. * (c) Copyright 1996-1997 Alan Cox <alan@lxorguk.ukuu.org.uk>,
  9. * All Rights Reserved.
  10. *
  11. * This program is free software; you can redistribute it and/or
  12. * modify it under the terms of the GNU General Public License
  13. * as published by the Free Software Foundation; either version
  14. * 2 of the License, or (at your option) any later version.
  15. *
  16. * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  17. * warranty for any of this software. This material is provided
  18. * "AS-IS" and at no charge.
  19. *
  20. * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
  21. *
  22. * This file is subject to the terms and conditions of the GNU General Public
  23. * License. See the file "COPYING" in the main directory of this archive
  24. * for more details.
  25. *
  26. *
  27. * The OCTEON watchdog has a maximum timeout of 2^32 * io_clock.
  28. * For most systems this is less than 10 seconds, so to allow for
  29. * software to request longer watchdog heartbeats, we maintain software
  30. * counters to count multiples of the base rate. If the system locks
  31. * up in such a manner that we can not run the software counters, the
  32. * only result is a watchdog reset sooner than was requested. But
  33. * that is OK, because in this case userspace would likely not be able
  34. * to do anything anyhow.
  35. *
  36. * The hardware watchdog interval we call the period. The OCTEON
  37. * watchdog goes through several stages, after the first period an
  38. * irq is asserted, then if it is not reset, after the next period NMI
  39. * is asserted, then after an additional period a chip wide soft reset.
  40. * So for the software counters, we reset watchdog after each period
  41. * and decrement the counter. But for the last two periods we need to
  42. * let the watchdog progress to the NMI stage so we disable the irq
  43. * and let it proceed. Once in the NMI, we print the register state
  44. * to the serial port and then wait for the reset.
  45. *
  46. * A watchdog is maintained for each CPU in the system, that way if
  47. * one CPU suffers a lockup, we also get a register dump and reset.
  48. * The userspace ping resets the watchdog on all CPUs.
  49. *
  50. * Before userspace opens the watchdog device, we still run the
  51. * watchdogs to catch any lockups that may be kernel related.
  52. *
  53. */
  54. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  55. #include <linux/miscdevice.h>
  56. #include <linux/interrupt.h>
  57. #include <linux/watchdog.h>
  58. #include <linux/cpumask.h>
  59. #include <linux/bitops.h>
  60. #include <linux/kernel.h>
  61. #include <linux/module.h>
  62. #include <linux/string.h>
  63. #include <linux/delay.h>
  64. #include <linux/cpu.h>
  65. #include <linux/smp.h>
  66. #include <linux/fs.h>
  67. #include <linux/irq.h>
  68. #include <asm/mipsregs.h>
  69. #include <asm/uasm.h>
  70. #include <asm/octeon/octeon.h>
  71. /* The count needed to achieve timeout_sec. */
  72. static unsigned int timeout_cnt;
  73. /* The maximum period supported. */
  74. static unsigned int max_timeout_sec;
  75. /* The current period. */
  76. static unsigned int timeout_sec;
  77. /* Set to non-zero when userspace countdown mode active */
  78. static int do_coundown;
  79. static unsigned int countdown_reset;
  80. static unsigned int per_cpu_countdown[NR_CPUS];
  81. static cpumask_t irq_enabled_cpus;
  82. #define WD_TIMO 60 /* Default heartbeat = 60 seconds */
  83. static int heartbeat = WD_TIMO;
  84. module_param(heartbeat, int, S_IRUGO);
  85. MODULE_PARM_DESC(heartbeat,
  86. "Watchdog heartbeat in seconds. (0 < heartbeat, default="
  87. __MODULE_STRING(WD_TIMO) ")");
  88. static bool nowayout = WATCHDOG_NOWAYOUT;
  89. module_param(nowayout, bool, S_IRUGO);
  90. MODULE_PARM_DESC(nowayout,
  91. "Watchdog cannot be stopped once started (default="
  92. __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  93. static unsigned long octeon_wdt_is_open;
  94. static char expect_close;
  95. static u32 __initdata nmi_stage1_insns[64];
  96. /* We need one branch and therefore one relocation per target label. */
  97. static struct uasm_label __initdata labels[5];
  98. static struct uasm_reloc __initdata relocs[5];
  99. enum lable_id {
  100. label_enter_bootloader = 1
  101. };
  102. /* Some CP0 registers */
  103. #define K0 26
  104. #define C0_CVMMEMCTL 11, 7
  105. #define C0_STATUS 12, 0
  106. #define C0_EBASE 15, 1
  107. #define C0_DESAVE 31, 0
  108. void octeon_wdt_nmi_stage2(void);
  109. static void __init octeon_wdt_build_stage1(void)
  110. {
  111. int i;
  112. int len;
  113. u32 *p = nmi_stage1_insns;
  114. #ifdef CONFIG_HOTPLUG_CPU
  115. struct uasm_label *l = labels;
  116. struct uasm_reloc *r = relocs;
  117. #endif
  118. /*
  119. * For the next few instructions running the debugger may
  120. * cause corruption of k0 in the saved registers. Since we're
  121. * about to crash, nobody probably cares.
  122. *
  123. * Save K0 into the debug scratch register
  124. */
  125. uasm_i_dmtc0(&p, K0, C0_DESAVE);
  126. uasm_i_mfc0(&p, K0, C0_STATUS);
  127. #ifdef CONFIG_HOTPLUG_CPU
  128. uasm_il_bbit0(&p, &r, K0, ilog2(ST0_NMI), label_enter_bootloader);
  129. #endif
  130. /* Force 64-bit addressing enabled */
  131. uasm_i_ori(&p, K0, K0, ST0_UX | ST0_SX | ST0_KX);
  132. uasm_i_mtc0(&p, K0, C0_STATUS);
  133. #ifdef CONFIG_HOTPLUG_CPU
  134. uasm_i_mfc0(&p, K0, C0_EBASE);
  135. /* Coreid number in K0 */
  136. uasm_i_andi(&p, K0, K0, 0xf);
  137. /* 8 * coreid in bits 16-31 */
  138. uasm_i_dsll_safe(&p, K0, K0, 3 + 16);
  139. uasm_i_ori(&p, K0, K0, 0x8001);
  140. uasm_i_dsll_safe(&p, K0, K0, 16);
  141. uasm_i_ori(&p, K0, K0, 0x0700);
  142. uasm_i_drotr_safe(&p, K0, K0, 32);
  143. /*
  144. * Should result in: 0x8001,0700,0000,8*coreid which is
  145. * CVMX_CIU_WDOGX(coreid) - 0x0500
  146. *
  147. * Now ld K0, CVMX_CIU_WDOGX(coreid)
  148. */
  149. uasm_i_ld(&p, K0, 0x500, K0);
  150. /*
  151. * If bit one set handle the NMI as a watchdog event.
  152. * otherwise transfer control to bootloader.
  153. */
  154. uasm_il_bbit0(&p, &r, K0, 1, label_enter_bootloader);
  155. uasm_i_nop(&p);
  156. #endif
  157. /* Clear Dcache so cvmseg works right. */
  158. uasm_i_cache(&p, 1, 0, 0);
  159. /* Use K0 to do a read/modify/write of CVMMEMCTL */
  160. uasm_i_dmfc0(&p, K0, C0_CVMMEMCTL);
  161. /* Clear out the size of CVMSEG */
  162. uasm_i_dins(&p, K0, 0, 0, 6);
  163. /* Set CVMSEG to its largest value */
  164. uasm_i_ori(&p, K0, K0, 0x1c0 | 54);
  165. /* Store the CVMMEMCTL value */
  166. uasm_i_dmtc0(&p, K0, C0_CVMMEMCTL);
  167. /* Load the address of the second stage handler */
  168. UASM_i_LA(&p, K0, (long)octeon_wdt_nmi_stage2);
  169. uasm_i_jr(&p, K0);
  170. uasm_i_dmfc0(&p, K0, C0_DESAVE);
  171. #ifdef CONFIG_HOTPLUG_CPU
  172. uasm_build_label(&l, p, label_enter_bootloader);
  173. /* Jump to the bootloader and restore K0 */
  174. UASM_i_LA(&p, K0, (long)octeon_bootloader_entry_addr);
  175. uasm_i_jr(&p, K0);
  176. uasm_i_dmfc0(&p, K0, C0_DESAVE);
  177. #endif
  178. uasm_resolve_relocs(relocs, labels);
  179. len = (int)(p - nmi_stage1_insns);
  180. pr_debug("Synthesized NMI stage 1 handler (%d instructions)\n", len);
  181. pr_debug("\t.set push\n");
  182. pr_debug("\t.set noreorder\n");
  183. for (i = 0; i < len; i++)
  184. pr_debug("\t.word 0x%08x\n", nmi_stage1_insns[i]);
  185. pr_debug("\t.set pop\n");
  186. if (len > 32)
  187. panic("NMI stage 1 handler exceeds 32 instructions, was %d\n", len);
  188. }
  189. static int cpu2core(int cpu)
  190. {
  191. #ifdef CONFIG_SMP
  192. return cpu_logical_map(cpu);
  193. #else
  194. return cvmx_get_core_num();
  195. #endif
  196. }
  197. static int core2cpu(int coreid)
  198. {
  199. #ifdef CONFIG_SMP
  200. return cpu_number_map(coreid);
  201. #else
  202. return 0;
  203. #endif
  204. }
  205. /**
  206. * Poke the watchdog when an interrupt is received
  207. *
  208. * @cpl:
  209. * @dev_id:
  210. *
  211. * Returns
  212. */
  213. static irqreturn_t octeon_wdt_poke_irq(int cpl, void *dev_id)
  214. {
  215. unsigned int core = cvmx_get_core_num();
  216. int cpu = core2cpu(core);
  217. if (do_coundown) {
  218. if (per_cpu_countdown[cpu] > 0) {
  219. /* We're alive, poke the watchdog */
  220. cvmx_write_csr(CVMX_CIU_PP_POKEX(core), 1);
  221. per_cpu_countdown[cpu]--;
  222. } else {
  223. /* Bad news, you are about to reboot. */
  224. disable_irq_nosync(cpl);
  225. cpumask_clear_cpu(cpu, &irq_enabled_cpus);
  226. }
  227. } else {
  228. /* Not open, just ping away... */
  229. cvmx_write_csr(CVMX_CIU_PP_POKEX(core), 1);
  230. }
  231. return IRQ_HANDLED;
  232. }
  233. /* From setup.c */
  234. extern int prom_putchar(char c);
  235. /**
  236. * Write a string to the uart
  237. *
  238. * @str: String to write
  239. */
  240. static void octeon_wdt_write_string(const char *str)
  241. {
  242. /* Just loop writing one byte at a time */
  243. while (*str)
  244. prom_putchar(*str++);
  245. }
  246. /**
  247. * Write a hex number out of the uart
  248. *
  249. * @value: Number to display
  250. * @digits: Number of digits to print (1 to 16)
  251. */
  252. static void octeon_wdt_write_hex(u64 value, int digits)
  253. {
  254. int d;
  255. int v;
  256. for (d = 0; d < digits; d++) {
  257. v = (value >> ((digits - d - 1) * 4)) & 0xf;
  258. if (v >= 10)
  259. prom_putchar('a' + v - 10);
  260. else
  261. prom_putchar('0' + v);
  262. }
  263. }
  264. const char *reg_name[] = {
  265. "$0", "at", "v0", "v1", "a0", "a1", "a2", "a3",
  266. "a4", "a5", "a6", "a7", "t0", "t1", "t2", "t3",
  267. "s0", "s1", "s2", "s3", "s4", "s5", "s6", "s7",
  268. "t8", "t9", "k0", "k1", "gp", "sp", "s8", "ra"
  269. };
  270. /**
  271. * NMI stage 3 handler. NMIs are handled in the following manner:
  272. * 1) The first NMI handler enables CVMSEG and transfers from
  273. * the bootbus region into normal memory. It is careful to not
  274. * destroy any registers.
  275. * 2) The second stage handler uses CVMSEG to save the registers
  276. * and create a stack for C code. It then calls the third level
  277. * handler with one argument, a pointer to the register values.
  278. * 3) The third, and final, level handler is the following C
  279. * function that prints out some useful infomration.
  280. *
  281. * @reg: Pointer to register state before the NMI
  282. */
  283. void octeon_wdt_nmi_stage3(u64 reg[32])
  284. {
  285. u64 i;
  286. unsigned int coreid = cvmx_get_core_num();
  287. /*
  288. * Save status and cause early to get them before any changes
  289. * might happen.
  290. */
  291. u64 cp0_cause = read_c0_cause();
  292. u64 cp0_status = read_c0_status();
  293. u64 cp0_error_epc = read_c0_errorepc();
  294. u64 cp0_epc = read_c0_epc();
  295. /* Delay so output from all cores output is not jumbled together. */
  296. __delay(100000000ull * coreid);
  297. octeon_wdt_write_string("\r\n*** NMI Watchdog interrupt on Core 0x");
  298. octeon_wdt_write_hex(coreid, 1);
  299. octeon_wdt_write_string(" ***\r\n");
  300. for (i = 0; i < 32; i++) {
  301. octeon_wdt_write_string("\t");
  302. octeon_wdt_write_string(reg_name[i]);
  303. octeon_wdt_write_string("\t0x");
  304. octeon_wdt_write_hex(reg[i], 16);
  305. if (i & 1)
  306. octeon_wdt_write_string("\r\n");
  307. }
  308. octeon_wdt_write_string("\terr_epc\t0x");
  309. octeon_wdt_write_hex(cp0_error_epc, 16);
  310. octeon_wdt_write_string("\tepc\t0x");
  311. octeon_wdt_write_hex(cp0_epc, 16);
  312. octeon_wdt_write_string("\r\n");
  313. octeon_wdt_write_string("\tstatus\t0x");
  314. octeon_wdt_write_hex(cp0_status, 16);
  315. octeon_wdt_write_string("\tcause\t0x");
  316. octeon_wdt_write_hex(cp0_cause, 16);
  317. octeon_wdt_write_string("\r\n");
  318. octeon_wdt_write_string("\tsum0\t0x");
  319. octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU_INTX_SUM0(coreid * 2)), 16);
  320. octeon_wdt_write_string("\ten0\t0x");
  321. octeon_wdt_write_hex(cvmx_read_csr(CVMX_CIU_INTX_EN0(coreid * 2)), 16);
  322. octeon_wdt_write_string("\r\n");
  323. octeon_wdt_write_string("*** Chip soft reset soon ***\r\n");
  324. }
  325. static void octeon_wdt_disable_interrupt(int cpu)
  326. {
  327. unsigned int core;
  328. unsigned int irq;
  329. union cvmx_ciu_wdogx ciu_wdog;
  330. core = cpu2core(cpu);
  331. irq = OCTEON_IRQ_WDOG0 + core;
  332. /* Poke the watchdog to clear out its state */
  333. cvmx_write_csr(CVMX_CIU_PP_POKEX(core), 1);
  334. /* Disable the hardware. */
  335. ciu_wdog.u64 = 0;
  336. cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
  337. free_irq(irq, octeon_wdt_poke_irq);
  338. }
  339. static void octeon_wdt_setup_interrupt(int cpu)
  340. {
  341. unsigned int core;
  342. unsigned int irq;
  343. union cvmx_ciu_wdogx ciu_wdog;
  344. core = cpu2core(cpu);
  345. /* Disable it before doing anything with the interrupts. */
  346. ciu_wdog.u64 = 0;
  347. cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
  348. per_cpu_countdown[cpu] = countdown_reset;
  349. irq = OCTEON_IRQ_WDOG0 + core;
  350. if (request_irq(irq, octeon_wdt_poke_irq,
  351. IRQF_NO_THREAD, "octeon_wdt", octeon_wdt_poke_irq))
  352. panic("octeon_wdt: Couldn't obtain irq %d", irq);
  353. cpumask_set_cpu(cpu, &irq_enabled_cpus);
  354. /* Poke the watchdog to clear out its state */
  355. cvmx_write_csr(CVMX_CIU_PP_POKEX(core), 1);
  356. /* Finally enable the watchdog now that all handlers are installed */
  357. ciu_wdog.u64 = 0;
  358. ciu_wdog.s.len = timeout_cnt;
  359. ciu_wdog.s.mode = 3; /* 3 = Interrupt + NMI + Soft-Reset */
  360. cvmx_write_csr(CVMX_CIU_WDOGX(core), ciu_wdog.u64);
  361. }
  362. static int octeon_wdt_cpu_callback(struct notifier_block *nfb,
  363. unsigned long action, void *hcpu)
  364. {
  365. unsigned int cpu = (unsigned long)hcpu;
  366. switch (action) {
  367. case CPU_DOWN_PREPARE:
  368. octeon_wdt_disable_interrupt(cpu);
  369. break;
  370. case CPU_ONLINE:
  371. case CPU_DOWN_FAILED:
  372. octeon_wdt_setup_interrupt(cpu);
  373. break;
  374. default:
  375. break;
  376. }
  377. return NOTIFY_OK;
  378. }
  379. static void octeon_wdt_ping(void)
  380. {
  381. int cpu;
  382. int coreid;
  383. for_each_online_cpu(cpu) {
  384. coreid = cpu2core(cpu);
  385. cvmx_write_csr(CVMX_CIU_PP_POKEX(coreid), 1);
  386. per_cpu_countdown[cpu] = countdown_reset;
  387. if ((countdown_reset || !do_coundown) &&
  388. !cpumask_test_cpu(cpu, &irq_enabled_cpus)) {
  389. /* We have to enable the irq */
  390. int irq = OCTEON_IRQ_WDOG0 + coreid;
  391. enable_irq(irq);
  392. cpumask_set_cpu(cpu, &irq_enabled_cpus);
  393. }
  394. }
  395. }
  396. static void octeon_wdt_calc_parameters(int t)
  397. {
  398. unsigned int periods;
  399. timeout_sec = max_timeout_sec;
  400. /*
  401. * Find the largest interrupt period, that can evenly divide
  402. * the requested heartbeat time.
  403. */
  404. while ((t % timeout_sec) != 0)
  405. timeout_sec--;
  406. periods = t / timeout_sec;
  407. /*
  408. * The last two periods are after the irq is disabled, and
  409. * then to the nmi, so we subtract them off.
  410. */
  411. countdown_reset = periods > 2 ? periods - 2 : 0;
  412. heartbeat = t;
  413. timeout_cnt = ((octeon_get_io_clock_rate() >> 8) * timeout_sec) >> 8;
  414. }
  415. static int octeon_wdt_set_heartbeat(int t)
  416. {
  417. int cpu;
  418. int coreid;
  419. union cvmx_ciu_wdogx ciu_wdog;
  420. if (t <= 0)
  421. return -1;
  422. octeon_wdt_calc_parameters(t);
  423. for_each_online_cpu(cpu) {
  424. coreid = cpu2core(cpu);
  425. cvmx_write_csr(CVMX_CIU_PP_POKEX(coreid), 1);
  426. ciu_wdog.u64 = 0;
  427. ciu_wdog.s.len = timeout_cnt;
  428. ciu_wdog.s.mode = 3; /* 3 = Interrupt + NMI + Soft-Reset */
  429. cvmx_write_csr(CVMX_CIU_WDOGX(coreid), ciu_wdog.u64);
  430. cvmx_write_csr(CVMX_CIU_PP_POKEX(coreid), 1);
  431. }
  432. octeon_wdt_ping(); /* Get the irqs back on. */
  433. return 0;
  434. }
  435. /**
  436. * octeon_wdt_write:
  437. * @file: file handle to the watchdog
  438. * @buf: buffer to write (unused as data does not matter here
  439. * @count: count of bytes
  440. * @ppos: pointer to the position to write. No seeks allowed
  441. *
  442. * A write to a watchdog device is defined as a keepalive signal. Any
  443. * write of data will do, as we we don't define content meaning.
  444. */
  445. static ssize_t octeon_wdt_write(struct file *file, const char __user *buf,
  446. size_t count, loff_t *ppos)
  447. {
  448. if (count) {
  449. if (!nowayout) {
  450. size_t i;
  451. /* In case it was set long ago */
  452. expect_close = 0;
  453. for (i = 0; i != count; i++) {
  454. char c;
  455. if (get_user(c, buf + i))
  456. return -EFAULT;
  457. if (c == 'V')
  458. expect_close = 1;
  459. }
  460. }
  461. octeon_wdt_ping();
  462. }
  463. return count;
  464. }
  465. /**
  466. * octeon_wdt_ioctl:
  467. * @file: file handle to the device
  468. * @cmd: watchdog command
  469. * @arg: argument pointer
  470. *
  471. * The watchdog API defines a common set of functions for all
  472. * watchdogs according to their available features. We only
  473. * actually usefully support querying capabilities and setting
  474. * the timeout.
  475. */
  476. static long octeon_wdt_ioctl(struct file *file, unsigned int cmd,
  477. unsigned long arg)
  478. {
  479. void __user *argp = (void __user *)arg;
  480. int __user *p = argp;
  481. int new_heartbeat;
  482. static struct watchdog_info ident = {
  483. .options = WDIOF_SETTIMEOUT|
  484. WDIOF_MAGICCLOSE|
  485. WDIOF_KEEPALIVEPING,
  486. .firmware_version = 1,
  487. .identity = "OCTEON",
  488. };
  489. switch (cmd) {
  490. case WDIOC_GETSUPPORT:
  491. return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
  492. case WDIOC_GETSTATUS:
  493. case WDIOC_GETBOOTSTATUS:
  494. return put_user(0, p);
  495. case WDIOC_KEEPALIVE:
  496. octeon_wdt_ping();
  497. return 0;
  498. case WDIOC_SETTIMEOUT:
  499. if (get_user(new_heartbeat, p))
  500. return -EFAULT;
  501. if (octeon_wdt_set_heartbeat(new_heartbeat))
  502. return -EINVAL;
  503. /* Fall through. */
  504. case WDIOC_GETTIMEOUT:
  505. return put_user(heartbeat, p);
  506. default:
  507. return -ENOTTY;
  508. }
  509. }
  510. /**
  511. * octeon_wdt_open:
  512. * @inode: inode of device
  513. * @file: file handle to device
  514. *
  515. * The watchdog device has been opened. The watchdog device is single
  516. * open and on opening we do a ping to reset the counters.
  517. */
  518. static int octeon_wdt_open(struct inode *inode, struct file *file)
  519. {
  520. if (test_and_set_bit(0, &octeon_wdt_is_open))
  521. return -EBUSY;
  522. /*
  523. * Activate
  524. */
  525. octeon_wdt_ping();
  526. do_coundown = 1;
  527. return nonseekable_open(inode, file);
  528. }
  529. /**
  530. * octeon_wdt_release:
  531. * @inode: inode to board
  532. * @file: file handle to board
  533. *
  534. * The watchdog has a configurable API. There is a religious dispute
  535. * between people who want their watchdog to be able to shut down and
  536. * those who want to be sure if the watchdog manager dies the machine
  537. * reboots. In the former case we disable the counters, in the latter
  538. * case you have to open it again very soon.
  539. */
  540. static int octeon_wdt_release(struct inode *inode, struct file *file)
  541. {
  542. if (expect_close) {
  543. do_coundown = 0;
  544. octeon_wdt_ping();
  545. } else {
  546. pr_crit("WDT device closed unexpectedly. WDT will not stop!\n");
  547. }
  548. clear_bit(0, &octeon_wdt_is_open);
  549. expect_close = 0;
  550. return 0;
  551. }
  552. static const struct file_operations octeon_wdt_fops = {
  553. .owner = THIS_MODULE,
  554. .llseek = no_llseek,
  555. .write = octeon_wdt_write,
  556. .unlocked_ioctl = octeon_wdt_ioctl,
  557. .open = octeon_wdt_open,
  558. .release = octeon_wdt_release,
  559. };
  560. static struct miscdevice octeon_wdt_miscdev = {
  561. .minor = WATCHDOG_MINOR,
  562. .name = "watchdog",
  563. .fops = &octeon_wdt_fops,
  564. };
  565. static struct notifier_block octeon_wdt_cpu_notifier = {
  566. .notifier_call = octeon_wdt_cpu_callback,
  567. };
  568. /**
  569. * Module/ driver initialization.
  570. *
  571. * Returns Zero on success
  572. */
  573. static int __init octeon_wdt_init(void)
  574. {
  575. int i;
  576. int ret;
  577. int cpu;
  578. u64 *ptr;
  579. /*
  580. * Watchdog time expiration length = The 16 bits of LEN
  581. * represent the most significant bits of a 24 bit decrementer
  582. * that decrements every 256 cycles.
  583. *
  584. * Try for a timeout of 5 sec, if that fails a smaller number
  585. * of even seconds,
  586. */
  587. max_timeout_sec = 6;
  588. do {
  589. max_timeout_sec--;
  590. timeout_cnt = ((octeon_get_io_clock_rate() >> 8) * max_timeout_sec) >> 8;
  591. } while (timeout_cnt > 65535);
  592. BUG_ON(timeout_cnt == 0);
  593. octeon_wdt_calc_parameters(heartbeat);
  594. pr_info("Initial granularity %d Sec\n", timeout_sec);
  595. ret = misc_register(&octeon_wdt_miscdev);
  596. if (ret) {
  597. pr_err("cannot register miscdev on minor=%d (err=%d)\n",
  598. WATCHDOG_MINOR, ret);
  599. goto out;
  600. }
  601. /* Build the NMI handler ... */
  602. octeon_wdt_build_stage1();
  603. /* ... and install it. */
  604. ptr = (u64 *) nmi_stage1_insns;
  605. for (i = 0; i < 16; i++) {
  606. cvmx_write_csr(CVMX_MIO_BOOT_LOC_ADR, i * 8);
  607. cvmx_write_csr(CVMX_MIO_BOOT_LOC_DAT, ptr[i]);
  608. }
  609. cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0x81fc0000);
  610. cpumask_clear(&irq_enabled_cpus);
  611. for_each_online_cpu(cpu)
  612. octeon_wdt_setup_interrupt(cpu);
  613. register_hotcpu_notifier(&octeon_wdt_cpu_notifier);
  614. out:
  615. return ret;
  616. }
  617. /**
  618. * Module / driver shutdown
  619. */
  620. static void __exit octeon_wdt_cleanup(void)
  621. {
  622. int cpu;
  623. misc_deregister(&octeon_wdt_miscdev);
  624. unregister_hotcpu_notifier(&octeon_wdt_cpu_notifier);
  625. for_each_online_cpu(cpu) {
  626. int core = cpu2core(cpu);
  627. /* Disable the watchdog */
  628. cvmx_write_csr(CVMX_CIU_WDOGX(core), 0);
  629. /* Free the interrupt handler */
  630. free_irq(OCTEON_IRQ_WDOG0 + core, octeon_wdt_poke_irq);
  631. }
  632. /*
  633. * Disable the boot-bus memory, the code it points to is soon
  634. * to go missing.
  635. */
  636. cvmx_write_csr(CVMX_MIO_BOOT_LOC_CFGX(0), 0);
  637. }
  638. MODULE_LICENSE("GPL");
  639. MODULE_AUTHOR("Cavium Networks <support@caviumnetworks.com>");
  640. MODULE_DESCRIPTION("Cavium Networks Octeon Watchdog driver.");
  641. module_init(octeon_wdt_init);
  642. module_exit(octeon_wdt_cleanup);