diff options
Diffstat (limited to 'drivers/watchdog/it8712f_wdt.c')
| -rw-r--r-- | drivers/watchdog/it8712f_wdt.c | 450 |
1 files changed, 450 insertions, 0 deletions
diff --git a/drivers/watchdog/it8712f_wdt.c b/drivers/watchdog/it8712f_wdt.c new file mode 100644 index 000000000..3ce6a58bd --- /dev/null +++ b/drivers/watchdog/it8712f_wdt.c @@ -0,0 +1,450 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * IT8712F "Smart Guardian" Watchdog support + * + * Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net> + * + * Based on info and code taken from: + * + * drivers/char/watchdog/scx200_wdt.c + * drivers/hwmon/it87.c + * IT8712F EC-LPC I/O Preliminary Specification 0.8.2 + * IT8712F EC-LPC I/O Preliminary Specification 0.9.3 + * + * The author(s) of this software shall not be held liable for damages + * of any nature resulting due to the use of this software. This + * software is provided AS-IS with no warranties. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/init.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/notifier.h> +#include <linux/reboot.h> +#include <linux/fs.h> +#include <linux/spinlock.h> +#include <linux/uaccess.h> +#include <linux/io.h> +#include <linux/ioport.h> + +#define NAME "it8712f_wdt" + +MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>"); +MODULE_DESCRIPTION("IT8712F Watchdog Driver"); +MODULE_LICENSE("GPL"); + +static int max_units = 255; +static int margin = 60; /* in seconds */ +module_param(margin, int, 0); +MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); + +static unsigned long wdt_open; +static unsigned expect_close; +static unsigned char revision; + +/* Dog Food address - We use the game port address */ +static unsigned short address; + +#define REG 0x2e /* The register to read/write */ +#define VAL 0x2f /* The value to read/write */ + +#define LDN 0x07 /* Register: Logical device select */ +#define DEVID 0x20 /* Register: Device ID */ +#define DEVREV 0x22 /* Register: Device Revision */ +#define ACT_REG 0x30 /* LDN Register: Activation */ +#define BASE_REG 0x60 /* LDN Register: Base address */ + +#define IT8712F_DEVID 0x8712 + +#define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */ +#define LDN_GAME 0x09 /* Game Port */ + +#define WDT_CONTROL 0x71 /* WDT Register: Control */ +#define WDT_CONFIG 0x72 /* WDT Register: Configuration */ +#define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */ + +#define WDT_RESET_GAME 0x10 /* Reset timer on read or write to game port */ +#define WDT_RESET_KBD 0x20 /* Reset timer on keyboard interrupt */ +#define WDT_RESET_MOUSE 0x40 /* Reset timer on mouse interrupt */ +#define WDT_RESET_CIR 0x80 /* Reset timer on consumer IR interrupt */ + +#define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */ + +#define WDT_OUT_PWROK 0x10 /* Pulse PWROK on timeout */ +#define WDT_OUT_KRST 0x40 /* Pulse reset on timeout */ + +static int wdt_control_reg = WDT_RESET_GAME; +module_param(wdt_control_reg, int, 0); +MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control " + "register. The default WDT_RESET_GAME resets the timer on " + "game port reads that this driver generates. You can also " + "use KBD, MOUSE or CIR if you have some external way to " + "generate those interrupts."); + +static int superio_inb(int reg) +{ + outb(reg, REG); + return inb(VAL); +} + +static void superio_outb(int val, int reg) +{ + outb(reg, REG); + outb(val, VAL); +} + +static int superio_inw(int reg) +{ + int val; + outb(reg++, REG); + val = inb(VAL) << 8; + outb(reg, REG); + val |= inb(VAL); + return val; +} + +static inline void superio_select(int ldn) +{ + outb(LDN, REG); + outb(ldn, VAL); +} + +static inline int superio_enter(void) +{ + /* + * Try to reserve REG and REG + 1 for exclusive access. + */ + if (!request_muxed_region(REG, 2, NAME)) + return -EBUSY; + + outb(0x87, REG); + outb(0x01, REG); + outb(0x55, REG); + outb(0x55, REG); + return 0; +} + +static inline void superio_exit(void) +{ + outb(0x02, REG); + outb(0x02, VAL); + release_region(REG, 2); +} + +static inline void it8712f_wdt_ping(void) +{ + if (wdt_control_reg & WDT_RESET_GAME) + inb(address); +} + +static void it8712f_wdt_update_margin(void) +{ + int config = WDT_OUT_KRST | WDT_OUT_PWROK; + int units = margin; + + /* Switch to minutes precision if the configured margin + * value does not fit within the register width. + */ + if (units <= max_units) { + config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */ + pr_info("timer margin %d seconds\n", units); + } else { + units /= 60; + pr_info("timer margin %d minutes\n", units); + } + superio_outb(config, WDT_CONFIG); + + if (revision >= 0x08) + superio_outb(units >> 8, WDT_TIMEOUT + 1); + superio_outb(units, WDT_TIMEOUT); +} + +static int it8712f_wdt_get_status(void) +{ + if (superio_inb(WDT_CONTROL) & 0x01) + return WDIOF_CARDRESET; + else + return 0; +} + +static int it8712f_wdt_enable(void) +{ + int ret = superio_enter(); + if (ret) + return ret; + + pr_debug("enabling watchdog timer\n"); + superio_select(LDN_GPIO); + + superio_outb(wdt_control_reg, WDT_CONTROL); + + it8712f_wdt_update_margin(); + + superio_exit(); + + it8712f_wdt_ping(); + + return 0; +} + +static int it8712f_wdt_disable(void) +{ + int ret = superio_enter(); + if (ret) + return ret; + + pr_debug("disabling watchdog timer\n"); + superio_select(LDN_GPIO); + + superio_outb(0, WDT_CONFIG); + superio_outb(0, WDT_CONTROL); + if (revision >= 0x08) + superio_outb(0, WDT_TIMEOUT + 1); + superio_outb(0, WDT_TIMEOUT); + + superio_exit(); + return 0; +} + +static int it8712f_wdt_notify(struct notifier_block *this, + unsigned long code, void *unused) +{ + if (code == SYS_HALT || code == SYS_POWER_OFF) + if (!nowayout) + it8712f_wdt_disable(); + + return NOTIFY_DONE; +} + +static struct notifier_block it8712f_wdt_notifier = { + .notifier_call = it8712f_wdt_notify, +}; + +static ssize_t it8712f_wdt_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + /* check for a magic close character */ + if (len) { + size_t i; + + it8712f_wdt_ping(); + + expect_close = 0; + for (i = 0; i < len; ++i) { + char c; + if (get_user(c, data + i)) + return -EFAULT; + if (c == 'V') + expect_close = 42; + } + } + + return len; +} + +static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + static const struct watchdog_info ident = { + .identity = "IT8712F Watchdog", + .firmware_version = 1, + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, + }; + int value; + int ret; + + switch (cmd) { + case WDIOC_GETSUPPORT: + if (copy_to_user(argp, &ident, sizeof(ident))) + return -EFAULT; + return 0; + case WDIOC_GETSTATUS: + ret = superio_enter(); + if (ret) + return ret; + superio_select(LDN_GPIO); + + value = it8712f_wdt_get_status(); + + superio_exit(); + + return put_user(value, p); + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + case WDIOC_KEEPALIVE: + it8712f_wdt_ping(); + return 0; + case WDIOC_SETTIMEOUT: + if (get_user(value, p)) + return -EFAULT; + if (value < 1) + return -EINVAL; + if (value > (max_units * 60)) + return -EINVAL; + margin = value; + ret = superio_enter(); + if (ret) + return ret; + superio_select(LDN_GPIO); + + it8712f_wdt_update_margin(); + + superio_exit(); + it8712f_wdt_ping(); + fallthrough; + case WDIOC_GETTIMEOUT: + if (put_user(margin, p)) + return -EFAULT; + return 0; + default: + return -ENOTTY; + } +} + +static int it8712f_wdt_open(struct inode *inode, struct file *file) +{ + int ret; + /* only allow one at a time */ + if (test_and_set_bit(0, &wdt_open)) + return -EBUSY; + + ret = it8712f_wdt_enable(); + if (ret) + return ret; + return stream_open(inode, file); +} + +static int it8712f_wdt_release(struct inode *inode, struct file *file) +{ + if (expect_close != 42) { + pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n"); + } else if (!nowayout) { + if (it8712f_wdt_disable()) + pr_warn("Watchdog disable failed\n"); + } + expect_close = 0; + clear_bit(0, &wdt_open); + + return 0; +} + +static const struct file_operations it8712f_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = it8712f_wdt_write, + .unlocked_ioctl = it8712f_wdt_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = it8712f_wdt_open, + .release = it8712f_wdt_release, +}; + +static struct miscdevice it8712f_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &it8712f_wdt_fops, +}; + +static int __init it8712f_wdt_find(unsigned short *address) +{ + int err = -ENODEV; + int chip_type; + int ret = superio_enter(); + if (ret) + return ret; + + chip_type = superio_inw(DEVID); + if (chip_type != IT8712F_DEVID) + goto exit; + + superio_select(LDN_GAME); + superio_outb(1, ACT_REG); + if (!(superio_inb(ACT_REG) & 0x01)) { + pr_err("Device not activated, skipping\n"); + goto exit; + } + + *address = superio_inw(BASE_REG); + if (*address == 0) { + pr_err("Base address not set, skipping\n"); + goto exit; + } + + err = 0; + revision = superio_inb(DEVREV) & 0x0f; + + /* Later revisions have 16-bit values per datasheet 0.9.1 */ + if (revision >= 0x08) + max_units = 65535; + + if (margin > (max_units * 60)) + margin = (max_units * 60); + + pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n", + chip_type, revision, *address); + +exit: + superio_exit(); + return err; +} + +static int __init it8712f_wdt_init(void) +{ + int err = 0; + + if (it8712f_wdt_find(&address)) + return -ENODEV; + + if (!request_region(address, 1, "IT8712F Watchdog")) { + pr_warn("watchdog I/O region busy\n"); + return -EBUSY; + } + + err = it8712f_wdt_disable(); + if (err) { + pr_err("unable to disable watchdog timer\n"); + goto out; + } + + err = register_reboot_notifier(&it8712f_wdt_notifier); + if (err) { + pr_err("unable to register reboot notifier\n"); + goto out; + } + + err = misc_register(&it8712f_wdt_miscdev); + if (err) { + pr_err("cannot register miscdev on minor=%d (err=%d)\n", + WATCHDOG_MINOR, err); + goto reboot_out; + } + + return 0; + + +reboot_out: + unregister_reboot_notifier(&it8712f_wdt_notifier); +out: + release_region(address, 1); + return err; +} + +static void __exit it8712f_wdt_exit(void) +{ + misc_deregister(&it8712f_wdt_miscdev); + unregister_reboot_notifier(&it8712f_wdt_notifier); + release_region(address, 1); +} + +module_init(it8712f_wdt_init); +module_exit(it8712f_wdt_exit); |