--- /dev/null
+/*
+ * 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 <fuganti@conectiva.com.br>
+ *
+ * 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 <Matt_Domsch@dell.com>
+ * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/ioport.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+
+/* 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 <fuganti@conectiva.com.br>");
+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);
Code Review / kvmfornfv.git / blobdiff