From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- drivers/watchdog/machzwd.c | 456 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 456 insertions(+) create mode 100644 drivers/watchdog/machzwd.c (limited to 'drivers/watchdog/machzwd.c') diff --git a/drivers/watchdog/machzwd.c b/drivers/watchdog/machzwd.c new file mode 100644 index 000000000..9826b59ef --- /dev/null +++ b/drivers/watchdog/machzwd.c @@ -0,0 +1,456 @@ +/* + * MachZ ZF-Logic Watchdog Timer driver for Linux + * + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * The author does NOT admit liability nor provide warranty for + * any of this software. This material is provided "AS-IS" in + * the hope that it may be useful for others. + * + * Author: Fernando Fuganti + * + * Based on sbc60xxwdt.c by Jakob Oestergaard + * + * + * We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the + * following periods: + * wd#1 - 2 seconds; + * wd#2 - 7.2 ms; + * After the expiration of wd#1, it can generate a NMI, SCI, SMI, or + * a system RESET and it starts wd#2 that unconditionally will RESET + * the system when the counter reaches zero. + * + * 14-Dec-2001 Matt Domsch + * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + + +/* ports */ +#define ZF_IOBASE 0x218 +#define INDEX 0x218 +#define DATA_B 0x219 +#define DATA_W 0x21A +#define DATA_D 0x21A + +/* indexes */ /* size */ +#define ZFL_VERSION 0x02 /* 16 */ +#define CONTROL 0x10 /* 16 */ +#define STATUS 0x12 /* 8 */ +#define COUNTER_1 0x0C /* 16 */ +#define COUNTER_2 0x0E /* 8 */ +#define PULSE_LEN 0x0F /* 8 */ + +/* controls */ +#define ENABLE_WD1 0x0001 +#define ENABLE_WD2 0x0002 +#define RESET_WD1 0x0010 +#define RESET_WD2 0x0020 +#define GEN_SCI 0x0100 +#define GEN_NMI 0x0200 +#define GEN_SMI 0x0400 +#define GEN_RESET 0x0800 + + +/* utilities */ + +#define WD1 0 +#define WD2 1 + +#define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); } +#define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); } +#define zf_get_ZFL_version() zf_readw(ZFL_VERSION) + + +static unsigned short zf_readw(unsigned char port) +{ + outb(port, INDEX); + return inw(DATA_W); +} + + +MODULE_AUTHOR("Fernando Fuganti "); +MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver"); +MODULE_LICENSE("GPL"); + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, + "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +#define PFX "machzwd" + +static const struct watchdog_info zf_info = { + .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, + .firmware_version = 1, + .identity = "ZF-Logic watchdog", +}; + + +/* + * action refers to action taken when watchdog resets + * 0 = GEN_RESET + * 1 = GEN_SMI + * 2 = GEN_NMI + * 3 = GEN_SCI + * defaults to GEN_RESET (0) + */ +static int action; +module_param(action, int, 0); +MODULE_PARM_DESC(action, "after watchdog resets, generate: " + "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI"); + +static void zf_ping(unsigned long data); + +static int zf_action = GEN_RESET; +static unsigned long zf_is_open; +static char zf_expect_close; +static DEFINE_SPINLOCK(zf_port_lock); +static DEFINE_TIMER(zf_timer, zf_ping, 0, 0); +static unsigned long next_heartbeat; + + +/* timeout for user land heart beat (10 seconds) */ +#define ZF_USER_TIMEO (HZ*10) + +/* timeout for hardware watchdog (~500ms) */ +#define ZF_HW_TIMEO (HZ/2) + +/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */ +#define ZF_CTIMEOUT 0xffff + +#ifndef ZF_DEBUG +#define dprintk(format, args...) +#else +#define dprintk(format, args...) \ + pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args) +#endif + + +static inline void zf_set_status(unsigned char new) +{ + zf_writeb(STATUS, new); +} + + +/* CONTROL register functions */ + +static inline unsigned short zf_get_control(void) +{ + return zf_readw(CONTROL); +} + +static inline void zf_set_control(unsigned short new) +{ + zf_writew(CONTROL, new); +} + + +/* WD#? counter functions */ +/* + * Just set counter value + */ + +static inline void zf_set_timer(unsigned short new, unsigned char n) +{ + switch (n) { + case WD1: + zf_writew(COUNTER_1, new); + case WD2: + zf_writeb(COUNTER_2, new > 0xff ? 0xff : new); + default: + return; + } +} + +/* + * stop hardware timer + */ +static void zf_timer_off(void) +{ + unsigned int ctrl_reg = 0; + unsigned long flags; + + /* stop internal ping */ + del_timer_sync(&zf_timer); + + spin_lock_irqsave(&zf_port_lock, flags); + /* stop watchdog timer */ + ctrl_reg = zf_get_control(); + ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */ + ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2); + zf_set_control(ctrl_reg); + spin_unlock_irqrestore(&zf_port_lock, flags); + + pr_info("Watchdog timer is now disabled\n"); +} + + +/* + * start hardware timer + */ +static void zf_timer_on(void) +{ + unsigned int ctrl_reg = 0; + unsigned long flags; + + spin_lock_irqsave(&zf_port_lock, flags); + + zf_writeb(PULSE_LEN, 0xff); + + zf_set_timer(ZF_CTIMEOUT, WD1); + + /* user land ping */ + next_heartbeat = jiffies + ZF_USER_TIMEO; + + /* start the timer for internal ping */ + mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); + + /* start watchdog timer */ + ctrl_reg = zf_get_control(); + ctrl_reg |= (ENABLE_WD1|zf_action); + zf_set_control(ctrl_reg); + spin_unlock_irqrestore(&zf_port_lock, flags); + + pr_info("Watchdog timer is now enabled\n"); +} + + +static void zf_ping(unsigned long data) +{ + unsigned int ctrl_reg = 0; + unsigned long flags; + + zf_writeb(COUNTER_2, 0xff); + + if (time_before(jiffies, next_heartbeat)) { + dprintk("time_before: %ld\n", next_heartbeat - jiffies); + /* + * reset event is activated by transition from 0 to 1 on + * RESET_WD1 bit and we assume that it is already zero... + */ + + spin_lock_irqsave(&zf_port_lock, flags); + ctrl_reg = zf_get_control(); + ctrl_reg |= RESET_WD1; + zf_set_control(ctrl_reg); + + /* ...and nothing changes until here */ + ctrl_reg &= ~(RESET_WD1); + zf_set_control(ctrl_reg); + spin_unlock_irqrestore(&zf_port_lock, flags); + + mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); + } else + pr_crit("I will reset your machine\n"); +} + +static ssize_t zf_write(struct file *file, const char __user *buf, size_t count, + loff_t *ppos) +{ + /* See if we got the magic character */ + if (count) { + /* + * no need to check for close confirmation + * no way to disable watchdog ;) + */ + if (!nowayout) { + size_t ofs; + /* + * note: just in case someone wrote the magic character + * five months ago... + */ + zf_expect_close = 0; + + /* now scan */ + for (ofs = 0; ofs != count; ofs++) { + char c; + if (get_user(c, buf + ofs)) + return -EFAULT; + if (c == 'V') { + zf_expect_close = 42; + dprintk("zf_expect_close = 42\n"); + } + } + } + + /* + * Well, anyhow someone wrote to us, + * we should return that favour + */ + next_heartbeat = jiffies + ZF_USER_TIMEO; + dprintk("user ping at %ld\n", jiffies); + } + return count; +} + +static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + switch (cmd) { + case WDIOC_GETSUPPORT: + if (copy_to_user(argp, &zf_info, sizeof(zf_info))) + return -EFAULT; + break; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + case WDIOC_KEEPALIVE: + zf_ping(0); + break; + default: + return -ENOTTY; + } + return 0; +} + +static int zf_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(0, &zf_is_open)) + return -EBUSY; + if (nowayout) + __module_get(THIS_MODULE); + zf_timer_on(); + return nonseekable_open(inode, file); +} + +static int zf_close(struct inode *inode, struct file *file) +{ + if (zf_expect_close == 42) + zf_timer_off(); + else { + del_timer(&zf_timer); + pr_err("device file closed unexpectedly. Will not stop the WDT!\n"); + } + clear_bit(0, &zf_is_open); + zf_expect_close = 0; + return 0; +} + +/* + * Notifier for system down + */ + +static int zf_notify_sys(struct notifier_block *this, unsigned long code, + void *unused) +{ + if (code == SYS_DOWN || code == SYS_HALT) + zf_timer_off(); + return NOTIFY_DONE; +} + +static const struct file_operations zf_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = zf_write, + .unlocked_ioctl = zf_ioctl, + .open = zf_open, + .release = zf_close, +}; + +static struct miscdevice zf_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &zf_fops, +}; + + +/* + * The device needs to learn about soft shutdowns in order to + * turn the timebomb registers off. + */ +static struct notifier_block zf_notifier = { + .notifier_call = zf_notify_sys, +}; + +static void __init zf_show_action(int act) +{ + static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" }; + + pr_info("Watchdog using action = %s\n", str[act]); +} + +static int __init zf_init(void) +{ + int ret; + + pr_info("MachZ ZF-Logic Watchdog driver initializing\n"); + + ret = zf_get_ZFL_version(); + if (!ret || ret == 0xffff) { + pr_warn("no ZF-Logic found\n"); + return -ENODEV; + } + + if (action <= 3 && action >= 0) + zf_action = zf_action >> action; + else + action = 0; + + zf_show_action(action); + + if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) { + pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE); + ret = -EBUSY; + goto no_region; + } + + ret = register_reboot_notifier(&zf_notifier); + if (ret) { + pr_err("can't register reboot notifier (err=%d)\n", ret); + goto no_reboot; + } + + ret = misc_register(&zf_miscdev); + if (ret) { + pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR); + goto no_misc; + } + + zf_set_status(0); + zf_set_control(0); + + return 0; + +no_misc: + unregister_reboot_notifier(&zf_notifier); +no_reboot: + release_region(ZF_IOBASE, 3); +no_region: + return ret; +} + + +static void __exit zf_exit(void) +{ + zf_timer_off(); + + misc_deregister(&zf_miscdev); + unregister_reboot_notifier(&zf_notifier); + release_region(ZF_IOBASE, 3); +} + +module_init(zf_init); +module_exit(zf_exit); -- cgit v1.2.3-54-g00ecf