drivers/watchdog/sch311x_wdt.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  *  sch311x_wdt.c - Driver for the SCH311x Super-I/O chips
0004  *          integrated watchdog.
0005  *
0006  *  (c) Copyright 2008 Wim Van Sebroeck <wim@iguana.be>.
0007  *
0008  *  Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
0009  *  provide warranty for any of this software. This material is
0010  *  provided "AS-IS" and at no charge.
0011  */
0012
0013 /*
0014  *  Includes, defines, variables, module parameters, ...
0015  */
0016
0017 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0018
0019 /* Includes */
0020 #include <linux/module.h>       /* For module specific items */
0021 #include <linux/moduleparam.h>      /* For new moduleparam's */
0022 #include <linux/types.h>        /* For standard types (like size_t) */
0023 #include <linux/errno.h>        /* For the -ENODEV/... values */
0024 #include <linux/kernel.h>       /* For printk/... */
0025 #include <linux/miscdevice.h>       /* For struct miscdevice */
0026 #include <linux/watchdog.h>     /* For the watchdog specific items */
0027 #include <linux/init.h>         /* For __init/__exit/... */
0028 #include <linux/fs.h>           /* For file operations */
0029 #include <linux/platform_device.h>  /* For platform_driver framework */
0030 #include <linux/ioport.h>       /* For io-port access */
0031 #include <linux/spinlock.h>     /* For spin_lock/spin_unlock/... */
0032 #include <linux/uaccess.h>      /* For copy_to_user/put_user/... */
0033 #include <linux/io.h>           /* For inb/outb/... */
0034
0035 /* Module and version information */
0036 #define DRV_NAME    "sch311x_wdt"
0037
0038 /* Runtime registers */
0039 #define GP60            0x47
0040 #define WDT_TIME_OUT        0x65
0041 #define WDT_VAL         0x66
0042 #define WDT_CFG         0x67
0043 #define WDT_CTRL        0x68
0044
0045 /* internal variables */
0046 static unsigned long sch311x_wdt_is_open;
0047 static char sch311x_wdt_expect_close;
0048 static struct platform_device *sch311x_wdt_pdev;
0049
0050 static int sch311x_ioports[] = { 0x2e, 0x4e, 0x162e, 0x164e, 0x00 };
0051
0052 static struct { /* The devices private data */
0053     /* the Runtime Register base address */
0054     unsigned short runtime_reg;
0055     /* The card's boot status */
0056     int boot_status;
0057     /* the lock for io operations */
0058     spinlock_t io_lock;
0059 } sch311x_wdt_data;
0060
0061 /* Module load parameters */
0062 static unsigned short force_id;
0063 module_param(force_id, ushort, 0);
0064 MODULE_PARM_DESC(force_id, "Override the detected device ID");
0065
0066 #define WATCHDOG_TIMEOUT 60     /* 60 sec default timeout */
0067 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
0068 module_param(timeout, int, 0);
0069 MODULE_PARM_DESC(timeout,
0070     "Watchdog timeout in seconds. 1<= timeout <=15300, default="
0071         __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
0072
0073 static bool nowayout = WATCHDOG_NOWAYOUT;
0074 module_param(nowayout, bool, 0);
0075 MODULE_PARM_DESC(nowayout,
0076     "Watchdog cannot be stopped once started (default="
0077         __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
0078
0079 /*
0080  *  Super-IO functions
0081  */
0082
0083 static inline void sch311x_sio_enter(int sio_config_port)
0084 {
0085     outb(0x55, sio_config_port);
0086 }
0087
0088 static inline void sch311x_sio_exit(int sio_config_port)
0089 {
0090     outb(0xaa, sio_config_port);
0091 }
0092
0093 static inline int sch311x_sio_inb(int sio_config_port, int reg)
0094 {
0095     outb(reg, sio_config_port);
0096     return inb(sio_config_port + 1);
0097 }
0098
0099 static inline void sch311x_sio_outb(int sio_config_port, int reg, int val)
0100 {
0101     outb(reg, sio_config_port);
0102     outb(val, sio_config_port + 1);
0103 }
0104
0105 /*
0106  *  Watchdog Operations
0107  */
0108
0109 static void sch311x_wdt_set_timeout(int t)
0110 {
0111     unsigned char timeout_unit = 0x80;
0112
0113     /* When new timeout is bigger then 255 seconds, we will use minutes */
0114     if (t > 255) {
0115         timeout_unit = 0;
0116         t /= 60;
0117     }
0118
0119     /* -- Watchdog Timeout --
0120      * Bit 0-6 (Reserved)
0121      * Bit 7   WDT Time-out Value Units Select
0122      *         (0 = Minutes, 1 = Seconds)
0123      */
0124     outb(timeout_unit, sch311x_wdt_data.runtime_reg + WDT_TIME_OUT);
0125
0126     /* -- Watchdog Timer Time-out Value --
0127      * Bit 0-7 Binary coded units (0=Disabled, 1..255)
0128      */
0129     outb(t, sch311x_wdt_data.runtime_reg + WDT_VAL);
0130 }
0131
0132 static void sch311x_wdt_start(void)
0133 {
0134     unsigned char t;
0135
0136     spin_lock(&sch311x_wdt_data.io_lock);
0137
0138     /* set watchdog's timeout */
0139     sch311x_wdt_set_timeout(timeout);
0140     /* enable the watchdog */
0141     /* -- General Purpose I/O Bit 6.0 --
0142      * Bit 0,   In/Out: 0 = Output, 1 = Input
0143      * Bit 1,   Polarity: 0 = No Invert, 1 = Invert
0144      * Bit 2-3, Function select: 00 = GPI/O, 01 = LED1, 11 = WDT,
0145      *                           10 = Either Edge Triggered Intr.4
0146      * Bit 4-6  (Reserved)
0147      * Bit 7,   Output Type: 0 = Push Pull Bit, 1 = Open Drain
0148      */
0149     t = inb(sch311x_wdt_data.runtime_reg + GP60);
0150     outb((t & ~0x0d) | 0x0c, sch311x_wdt_data.runtime_reg + GP60);
0151
0152     spin_unlock(&sch311x_wdt_data.io_lock);
0153
0154 }
0155
0156 static void sch311x_wdt_stop(void)
0157 {
0158     unsigned char t;
0159
0160     spin_lock(&sch311x_wdt_data.io_lock);
0161
0162     /* stop the watchdog */
0163     t = inb(sch311x_wdt_data.runtime_reg + GP60);
0164     outb((t & ~0x0d) | 0x01, sch311x_wdt_data.runtime_reg + GP60);
0165     /* disable timeout by setting it to 0 */
0166     sch311x_wdt_set_timeout(0);
0167
0168     spin_unlock(&sch311x_wdt_data.io_lock);
0169 }
0170
0171 static void sch311x_wdt_keepalive(void)
0172 {
0173     spin_lock(&sch311x_wdt_data.io_lock);
0174     sch311x_wdt_set_timeout(timeout);
0175     spin_unlock(&sch311x_wdt_data.io_lock);
0176 }
0177
0178 static int sch311x_wdt_set_heartbeat(int t)
0179 {
0180     if (t < 1 || t > (255*60))
0181         return -EINVAL;
0182
0183     /* When new timeout is bigger then 255 seconds,
0184      * we will round up to minutes (with a max of 255) */
0185     if (t > 255)
0186         t = (((t - 1) / 60) + 1) * 60;
0187
0188     timeout = t;
0189     return 0;
0190 }
0191
0192 static void sch311x_wdt_get_status(int *status)
0193 {
0194     unsigned char new_status;
0195
0196     *status = 0;
0197
0198     spin_lock(&sch311x_wdt_data.io_lock);
0199
0200     /* -- Watchdog timer control --
0201      * Bit 0   Status Bit: 0 = Timer counting, 1 = Timeout occurred
0202      * Bit 1   Reserved
0203      * Bit 2   Force Timeout: 1 = Forces WD timeout event (self-cleaning)
0204      * Bit 3   P20 Force Timeout enabled:
0205      *          0 = P20 activity does not generate the WD timeout event
0206      *          1 = P20 Allows rising edge of P20, from the keyboard
0207      *              controller, to force the WD timeout event.
0208      * Bit 4-7 Reserved
0209      */
0210     new_status = inb(sch311x_wdt_data.runtime_reg + WDT_CTRL);
0211     if (new_status & 0x01)
0212         *status |= WDIOF_CARDRESET;
0213
0214     spin_unlock(&sch311x_wdt_data.io_lock);
0215 }
0216
0217 /*
0218  *  /dev/watchdog handling
0219  */
0220
0221 static ssize_t sch311x_wdt_write(struct file *file, const char __user *buf,
0222                         size_t count, loff_t *ppos)
0223 {
0224     if (count) {
0225         if (!nowayout) {
0226             size_t i;
0227
0228             sch311x_wdt_expect_close = 0;
0229
0230             for (i = 0; i != count; i++) {
0231                 char c;
0232                 if (get_user(c, buf + i))
0233                     return -EFAULT;
0234                 if (c == 'V')
0235                     sch311x_wdt_expect_close = 42;
0236             }
0237         }
0238         sch311x_wdt_keepalive();
0239     }
0240     return count;
0241 }
0242
0243 static long sch311x_wdt_ioctl(struct file *file, unsigned int cmd,
0244                             unsigned long arg)
0245 {
0246     int status;
0247     int new_timeout;
0248     void __user *argp = (void __user *)arg;
0249     int __user *p = argp;
0250     static const struct watchdog_info ident = {
0251         .options        = WDIOF_KEEPALIVEPING |
0252                       WDIOF_SETTIMEOUT |
0253                       WDIOF_MAGICCLOSE,
0254         .firmware_version   = 1,
0255         .identity       = DRV_NAME,
0256     };
0257
0258     switch (cmd) {
0259     case WDIOC_GETSUPPORT:
0260         if (copy_to_user(argp, &ident, sizeof(ident)))
0261             return -EFAULT;
0262         break;
0263
0264     case WDIOC_GETSTATUS:
0265     {
0266         sch311x_wdt_get_status(&status);
0267         return put_user(status, p);
0268     }
0269     case WDIOC_GETBOOTSTATUS:
0270         return put_user(sch311x_wdt_data.boot_status, p);
0271
0272     case WDIOC_SETOPTIONS:
0273     {
0274         int options, retval = -EINVAL;
0275
0276         if (get_user(options, p))
0277             return -EFAULT;
0278         if (options & WDIOS_DISABLECARD) {
0279             sch311x_wdt_stop();
0280             retval = 0;
0281         }
0282         if (options & WDIOS_ENABLECARD) {
0283             sch311x_wdt_start();
0284             retval = 0;
0285         }
0286         return retval;
0287     }
0288     case WDIOC_KEEPALIVE:
0289         sch311x_wdt_keepalive();
0290         break;
0291
0292     case WDIOC_SETTIMEOUT:
0293         if (get_user(new_timeout, p))
0294             return -EFAULT;
0295         if (sch311x_wdt_set_heartbeat(new_timeout))
0296             return -EINVAL;
0297         sch311x_wdt_keepalive();
0298         fallthrough;
0299     case WDIOC_GETTIMEOUT:
0300         return put_user(timeout, p);
0301     default:
0302         return -ENOTTY;
0303     }
0304     return 0;
0305 }
0306
0307 static int sch311x_wdt_open(struct inode *inode, struct file *file)
0308 {
0309     if (test_and_set_bit(0, &sch311x_wdt_is_open))
0310         return -EBUSY;
0311     /*
0312      *  Activate
0313      */
0314     sch311x_wdt_start();
0315     return stream_open(inode, file);
0316 }
0317
0318 static int sch311x_wdt_close(struct inode *inode, struct file *file)
0319 {
0320     if (sch311x_wdt_expect_close == 42) {
0321         sch311x_wdt_stop();
0322     } else {
0323         pr_crit("Unexpected close, not stopping watchdog!\n");
0324         sch311x_wdt_keepalive();
0325     }
0326     clear_bit(0, &sch311x_wdt_is_open);
0327     sch311x_wdt_expect_close = 0;
0328     return 0;
0329 }
0330
0331 /*
0332  *  Kernel Interfaces
0333  */
0334
0335 static const struct file_operations sch311x_wdt_fops = {
0336     .owner      = THIS_MODULE,
0337     .llseek     = no_llseek,
0338     .write      = sch311x_wdt_write,
0339     .unlocked_ioctl = sch311x_wdt_ioctl,
0340     .compat_ioctl   = compat_ptr_ioctl,
0341     .open       = sch311x_wdt_open,
0342     .release    = sch311x_wdt_close,
0343 };
0344
0345 static struct miscdevice sch311x_wdt_miscdev = {
0346     .minor  = WATCHDOG_MINOR,
0347     .name   = "watchdog",
0348     .fops   = &sch311x_wdt_fops,
0349 };
0350
0351 /*
0352  *  Init & exit routines
0353  */
0354
0355 static int sch311x_wdt_probe(struct platform_device *pdev)
0356 {
0357     struct device *dev = &pdev->dev;
0358     int err;
0359
0360     spin_lock_init(&sch311x_wdt_data.io_lock);
0361
0362     if (!request_region(sch311x_wdt_data.runtime_reg + GP60, 1, DRV_NAME)) {
0363         dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
0364             sch311x_wdt_data.runtime_reg + GP60,
0365             sch311x_wdt_data.runtime_reg + GP60);
0366         err = -EBUSY;
0367         goto exit;
0368     }
0369
0370     if (!request_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4,
0371                                 DRV_NAME)) {
0372         dev_err(dev, "Failed to request region 0x%04x-0x%04x.\n",
0373             sch311x_wdt_data.runtime_reg + WDT_TIME_OUT,
0374             sch311x_wdt_data.runtime_reg + WDT_CTRL);
0375         err = -EBUSY;
0376         goto exit_release_region;
0377     }
0378
0379     /* Make sure that the watchdog is not running */
0380     sch311x_wdt_stop();
0381
0382     /* Disable keyboard and mouse interaction and interrupt */
0383     /* -- Watchdog timer configuration --
0384      * Bit 0   Reserved
0385      * Bit 1   Keyboard enable: 0* = No Reset, 1 = Reset WDT upon KBD Intr.
0386      * Bit 2   Mouse enable: 0* = No Reset, 1 = Reset WDT upon Mouse Intr
0387      * Bit 3   Reserved
0388      * Bit 4-7 WDT Interrupt Mapping: (0000* = Disabled,
0389      *            0001=IRQ1, 0010=(Invalid), 0011=IRQ3 to 1111=IRQ15)
0390      */
0391     outb(0, sch311x_wdt_data.runtime_reg + WDT_CFG);
0392
0393     /* Check that the heartbeat value is within it's range ;
0394      * if not reset to the default */
0395     if (sch311x_wdt_set_heartbeat(timeout)) {
0396         sch311x_wdt_set_heartbeat(WATCHDOG_TIMEOUT);
0397         dev_info(dev, "timeout value must be 1<=x<=15300, using %d\n",
0398             timeout);
0399     }
0400
0401     /* Get status at boot */
0402     sch311x_wdt_get_status(&sch311x_wdt_data.boot_status);
0403
0404     sch311x_wdt_miscdev.parent = dev;
0405
0406     err = misc_register(&sch311x_wdt_miscdev);
0407     if (err != 0) {
0408         dev_err(dev, "cannot register miscdev on minor=%d (err=%d)\n",
0409                             WATCHDOG_MINOR, err);
0410         goto exit_release_region2;
0411     }
0412
0413     dev_info(dev,
0414         "SMSC SCH311x WDT initialized. timeout=%d sec (nowayout=%d)\n",
0415         timeout, nowayout);
0416
0417     return 0;
0418
0419 exit_release_region2:
0420     release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
0421 exit_release_region:
0422     release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
0423     sch311x_wdt_data.runtime_reg = 0;
0424 exit:
0425     return err;
0426 }
0427
0428 static int sch311x_wdt_remove(struct platform_device *pdev)
0429 {
0430     /* Stop the timer before we leave */
0431     if (!nowayout)
0432         sch311x_wdt_stop();
0433
0434     /* Deregister */
0435     misc_deregister(&sch311x_wdt_miscdev);
0436     release_region(sch311x_wdt_data.runtime_reg + WDT_TIME_OUT, 4);
0437     release_region(sch311x_wdt_data.runtime_reg + GP60, 1);
0438     sch311x_wdt_data.runtime_reg = 0;
0439     return 0;
0440 }
0441
0442 static void sch311x_wdt_shutdown(struct platform_device *dev)
0443 {
0444     /* Turn the WDT off if we have a soft shutdown */
0445     sch311x_wdt_stop();
0446 }
0447
0448 static struct platform_driver sch311x_wdt_driver = {
0449     .probe      = sch311x_wdt_probe,
0450     .remove     = sch311x_wdt_remove,
0451     .shutdown   = sch311x_wdt_shutdown,
0452     .driver     = {
0453         .name = DRV_NAME,
0454     },
0455 };
0456
0457 static int __init sch311x_detect(int sio_config_port, unsigned short *addr)
0458 {
0459     int err = 0, reg;
0460     unsigned short base_addr;
0461     unsigned char dev_id;
0462
0463     sch311x_sio_enter(sio_config_port);
0464
0465     /* Check device ID. We currently know about:
0466      * SCH3112 (0x7c), SCH3114 (0x7d), and SCH3116 (0x7f). */
0467     reg = force_id ? force_id : sch311x_sio_inb(sio_config_port, 0x20);
0468     if (!(reg == 0x7c || reg == 0x7d || reg == 0x7f)) {
0469         err = -ENODEV;
0470         goto exit;
0471     }
0472     dev_id = reg == 0x7c ? 2 : reg == 0x7d ? 4 : 6;
0473
0474     /* Select logical device A (runtime registers) */
0475     sch311x_sio_outb(sio_config_port, 0x07, 0x0a);
0476
0477     /* Check if Logical Device Register is currently active */
0478     if ((sch311x_sio_inb(sio_config_port, 0x30) & 0x01) == 0)
0479         pr_info("Seems that LDN 0x0a is not active...\n");
0480
0481     /* Get the base address of the runtime registers */
0482     base_addr = (sch311x_sio_inb(sio_config_port, 0x60) << 8) |
0483                sch311x_sio_inb(sio_config_port, 0x61);
0484     if (!base_addr) {
0485         pr_err("Base address not set\n");
0486         err = -ENODEV;
0487         goto exit;
0488     }
0489     *addr = base_addr;
0490
0491     pr_info("Found an SMSC SCH311%d chip at 0x%04x\n", dev_id, base_addr);
0492
0493 exit:
0494     sch311x_sio_exit(sio_config_port);
0495     return err;
0496 }
0497
0498 static int __init sch311x_wdt_init(void)
0499 {
0500     int err, i, found = 0;
0501     unsigned short addr = 0;
0502
0503     for (i = 0; !found && sch311x_ioports[i]; i++)
0504         if (sch311x_detect(sch311x_ioports[i], &addr) == 0)
0505             found++;
0506
0507     if (!found)
0508         return -ENODEV;
0509
0510     sch311x_wdt_data.runtime_reg = addr;
0511
0512     err = platform_driver_register(&sch311x_wdt_driver);
0513     if (err)
0514         return err;
0515
0516     sch311x_wdt_pdev = platform_device_register_simple(DRV_NAME, addr,
0517                                 NULL, 0);
0518
0519     if (IS_ERR(sch311x_wdt_pdev)) {
0520         err = PTR_ERR(sch311x_wdt_pdev);
0521         goto unreg_platform_driver;
0522     }
0523
0524     return 0;
0525
0526 unreg_platform_driver:
0527     platform_driver_unregister(&sch311x_wdt_driver);
0528     return err;
0529 }
0530
0531 static void __exit sch311x_wdt_exit(void)
0532 {
0533     platform_device_unregister(sch311x_wdt_pdev);
0534     platform_driver_unregister(&sch311x_wdt_driver);
0535 }
0536
0537 module_init(sch311x_wdt_init);
0538 module_exit(sch311x_wdt_exit);
0539
0540 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
0541 MODULE_DESCRIPTION("SMSC SCH311x WatchDog Timer Driver");
0542 MODULE_LICENSE("GPL");