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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Watchdog for the 7101 PMU version found in the ALi M1535 chipsets4 */5 6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt7 8#include <linux/module.h>9#include <linux/moduleparam.h>10#include <linux/types.h>11#include <linux/miscdevice.h>12#include <linux/watchdog.h>13#include <linux/ioport.h>14#include <linux/notifier.h>15#include <linux/reboot.h>16#include <linux/init.h>17#include <linux/fs.h>18#include <linux/pci.h>19#include <linux/uaccess.h>20#include <linux/io.h>21 22#define WATCHDOG_NAME "ALi_M1535"23#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */24 25/* internal variables */26static unsigned long ali_is_open;27static char ali_expect_release;28static struct pci_dev *ali_pci;29static u32 ali_timeout_bits; /* stores the computed timeout */30static DEFINE_SPINLOCK(ali_lock); /* Guards the hardware */31 32/* module parameters */33static int timeout = WATCHDOG_TIMEOUT;34module_param(timeout, int, 0);35MODULE_PARM_DESC(timeout,36 "Watchdog timeout in seconds. (0 < timeout < 18000, default="37 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");38 39static bool nowayout = WATCHDOG_NOWAYOUT;40module_param(nowayout, bool, 0);41MODULE_PARM_DESC(nowayout,42 "Watchdog cannot be stopped once started (default="43 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");44 45/*46 * ali_start - start watchdog countdown47 *48 * Starts the timer running providing the timer has a counter49 * configuration set.50 */51 52static void ali_start(void)53{54 u32 val;55 56 spin_lock(&ali_lock);57 58 pci_read_config_dword(ali_pci, 0xCC, &val);59 val &= ~0x3F; /* Mask count */60 val |= (1 << 25) | ali_timeout_bits;61 pci_write_config_dword(ali_pci, 0xCC, val);62 63 spin_unlock(&ali_lock);64}65 66/*67 * ali_stop - stop the timer countdown68 *69 * Stop the ALi watchdog countdown70 */71 72static void ali_stop(void)73{74 u32 val;75 76 spin_lock(&ali_lock);77 78 pci_read_config_dword(ali_pci, 0xCC, &val);79 val &= ~0x3F; /* Mask count to zero (disabled) */80 val &= ~(1 << 25); /* and for safety mask the reset enable */81 pci_write_config_dword(ali_pci, 0xCC, val);82 83 spin_unlock(&ali_lock);84}85 86/*87 * ali_keepalive - send a keepalive to the watchdog88 *89 * Send a keepalive to the timer (actually we restart the timer).90 */91 92static void ali_keepalive(void)93{94 ali_start();95}96 97/*98 * ali_settimer - compute the timer reload value99 * @t: time in seconds100 *101 * Computes the timeout values needed102 */103 104static int ali_settimer(int t)105{106 if (t < 0)107 return -EINVAL;108 else if (t < 60)109 ali_timeout_bits = t|(1 << 6);110 else if (t < 3600)111 ali_timeout_bits = (t / 60)|(1 << 7);112 else if (t < 18000)113 ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7);114 else115 return -EINVAL;116 117 timeout = t;118 return 0;119}120 121/*122 * /dev/watchdog handling123 */124 125/*126 * ali_write - writes to ALi watchdog127 * @file: file from VFS128 * @data: user address of data129 * @len: length of data130 * @ppos: pointer to the file offset131 *132 * Handle a write to the ALi watchdog. Writing to the file pings133 * the watchdog and resets it. Writing the magic 'V' sequence allows134 * the next close to turn off the watchdog.135 */136 137static ssize_t ali_write(struct file *file, const char __user *data,138 size_t len, loff_t *ppos)139{140 /* See if we got the magic character 'V' and reload the timer */141 if (len) {142 if (!nowayout) {143 size_t i;144 145 /* note: just in case someone wrote the146 magic character five months ago... */147 ali_expect_release = 0;148 149 /* scan to see whether or not we got150 the magic character */151 for (i = 0; i != len; i++) {152 char c;153 if (get_user(c, data + i))154 return -EFAULT;155 if (c == 'V')156 ali_expect_release = 42;157 }158 }159 160 /* someone wrote to us, we should reload the timer */161 ali_start();162 }163 return len;164}165 166/*167 * ali_ioctl - handle watchdog ioctls168 * @file: VFS file pointer169 * @cmd: ioctl number170 * @arg: arguments to the ioctl171 *172 * Handle the watchdog ioctls supported by the ALi driver. Really173 * we want an extension to enable irq ack monitoring and the like174 */175 176static long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg)177{178 void __user *argp = (void __user *)arg;179 int __user *p = argp;180 static const struct watchdog_info ident = {181 .options = WDIOF_KEEPALIVEPING |182 WDIOF_SETTIMEOUT |183 WDIOF_MAGICCLOSE,184 .firmware_version = 0,185 .identity = "ALi M1535 WatchDog Timer",186 };187 188 switch (cmd) {189 case WDIOC_GETSUPPORT:190 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;191 192 case WDIOC_GETSTATUS:193 case WDIOC_GETBOOTSTATUS:194 return put_user(0, p);195 case WDIOC_SETOPTIONS:196 {197 int new_options, retval = -EINVAL;198 199 if (get_user(new_options, p))200 return -EFAULT;201 if (new_options & WDIOS_DISABLECARD) {202 ali_stop();203 retval = 0;204 }205 if (new_options & WDIOS_ENABLECARD) {206 ali_start();207 retval = 0;208 }209 return retval;210 }211 case WDIOC_KEEPALIVE:212 ali_keepalive();213 return 0;214 case WDIOC_SETTIMEOUT:215 {216 int new_timeout;217 if (get_user(new_timeout, p))218 return -EFAULT;219 if (ali_settimer(new_timeout))220 return -EINVAL;221 ali_keepalive();222 }223 fallthrough;224 case WDIOC_GETTIMEOUT:225 return put_user(timeout, p);226 default:227 return -ENOTTY;228 }229}230 231/*232 * ali_open - handle open of ali watchdog233 * @inode: inode from VFS234 * @file: file from VFS235 *236 * Open the ALi watchdog device. Ensure only one person opens it237 * at a time. Also start the watchdog running.238 */239 240static int ali_open(struct inode *inode, struct file *file)241{242 /* /dev/watchdog can only be opened once */243 if (test_and_set_bit(0, &ali_is_open))244 return -EBUSY;245 246 /* Activate */247 ali_start();248 return stream_open(inode, file);249}250 251/*252 * ali_release - close an ALi watchdog253 * @inode: inode from VFS254 * @file: file from VFS255 *256 * Close the ALi watchdog device. Actual shutdown of the timer257 * only occurs if the magic sequence has been set.258 */259 260static int ali_release(struct inode *inode, struct file *file)261{262 /*263 * Shut off the timer.264 */265 if (ali_expect_release == 42)266 ali_stop();267 else {268 pr_crit("Unexpected close, not stopping watchdog!\n");269 ali_keepalive();270 }271 clear_bit(0, &ali_is_open);272 ali_expect_release = 0;273 return 0;274}275 276/*277 * ali_notify_sys - System down notifier278 *279 * Notifier for system down280 */281 282 283static int ali_notify_sys(struct notifier_block *this,284 unsigned long code, void *unused)285{286 if (code == SYS_DOWN || code == SYS_HALT)287 ali_stop(); /* Turn the WDT off */288 return NOTIFY_DONE;289}290 291/*292 * Data for PCI driver interface293 *294 * This data only exists for exporting the supported295 * PCI ids via MODULE_DEVICE_TABLE. We do not actually296 * register a pci_driver, because someone else might one day297 * want to register another driver on the same PCI id.298 */299 300static const struct pci_device_id ali_pci_tbl[] __used = {301 { PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,},302 { PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,},303 { 0, },304};305MODULE_DEVICE_TABLE(pci, ali_pci_tbl);306 307/*308 * ali_find_watchdog - find a 1535 and 7101309 *310 * Scans the PCI hardware for a 1535 series bridge and matching 7101311 * watchdog device. This may be overtight but it is better to be safe312 */313 314static int __init ali_find_watchdog(void)315{316 struct pci_dev *pdev;317 u32 wdog;318 319 /* Check for a 1533/1535 series bridge */320 pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL);321 if (pdev == NULL)322 pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL);323 if (pdev == NULL)324 return -ENODEV;325 pci_dev_put(pdev);326 327 /* Check for the a 7101 PMU */328 pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL);329 if (pdev == NULL)330 return -ENODEV;331 332 if (pci_enable_device(pdev)) {333 pci_dev_put(pdev);334 return -EIO;335 }336 337 ali_pci = pdev;338 339 /*340 * Initialize the timer bits341 */342 pci_read_config_dword(pdev, 0xCC, &wdog);343 344 /* Timer bits */345 wdog &= ~0x3F;346 /* Issued events */347 wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24));348 /* No monitor bits */349 wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9));350 351 pci_write_config_dword(pdev, 0xCC, wdog);352 353 return 0;354}355 356/*357 * Kernel Interfaces358 */359 360static const struct file_operations ali_fops = {361 .owner = THIS_MODULE,362 .write = ali_write,363 .unlocked_ioctl = ali_ioctl,364 .compat_ioctl = compat_ptr_ioctl,365 .open = ali_open,366 .release = ali_release,367};368 369static struct miscdevice ali_miscdev = {370 .minor = WATCHDOG_MINOR,371 .name = "watchdog",372 .fops = &ali_fops,373};374 375static struct notifier_block ali_notifier = {376 .notifier_call = ali_notify_sys,377};378 379/*380 * watchdog_init - module initialiser381 *382 * Scan for a suitable watchdog and if so initialize it. Return an error383 * if we cannot, the error causes the module to unload384 */385 386static int __init watchdog_init(void)387{388 int ret;389 390 /* Check whether or not the hardware watchdog is there */391 if (ali_find_watchdog() != 0)392 return -ENODEV;393 394 /* Check that the timeout value is within it's range;395 if not reset to the default */396 if (timeout < 1 || timeout >= 18000) {397 timeout = WATCHDOG_TIMEOUT;398 pr_info("timeout value must be 0 < timeout < 18000, using %d\n",399 timeout);400 }401 402 /* Calculate the watchdog's timeout */403 ali_settimer(timeout);404 405 ret = register_reboot_notifier(&ali_notifier);406 if (ret != 0) {407 pr_err("cannot register reboot notifier (err=%d)\n", ret);408 goto out;409 }410 411 ret = misc_register(&ali_miscdev);412 if (ret != 0) {413 pr_err("cannot register miscdev on minor=%d (err=%d)\n",414 WATCHDOG_MINOR, ret);415 goto unreg_reboot;416 }417 418 pr_info("initialized. timeout=%d sec (nowayout=%d)\n",419 timeout, nowayout);420 421out:422 return ret;423unreg_reboot:424 unregister_reboot_notifier(&ali_notifier);425 goto out;426}427 428/*429 * watchdog_exit - module de-initialiser430 *431 * Called while unloading a successfully installed watchdog module.432 */433 434static void __exit watchdog_exit(void)435{436 /* Stop the timer before we leave */437 ali_stop();438 439 /* Deregister */440 misc_deregister(&ali_miscdev);441 unregister_reboot_notifier(&ali_notifier);442 pci_dev_put(ali_pci);443}444 445module_init(watchdog_init);446module_exit(watchdog_exit);447 448MODULE_AUTHOR("Alan Cox");449MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");450MODULE_LICENSE("GPL");451