/***************************************************************************
- * Copyright (C) 2010-2011 Hans de Goede <hdegoede@redhat.com> *
+ * Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com> *
* *
* 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 *
#include <linux/io.h>
#include <linux/acpi.h>
#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/watchdog.h>
+#include <linux/miscdevice.h>
+#include <linux/uaccess.h>
+#include <linux/kref.h>
+#include <linux/slab.h>
#include "sch56xx-common.h"
+/* Insmod parameters */
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
#define SIO_SCH56XX_LD_EM 0x0C /* Embedded uController Logical Dev */
#define SIO_UNLOCK_KEY 0x55 /* Key to enable Super-I/O */
#define SIO_LOCK_KEY 0xAA /* Key to disable Super-I/O */
#define SIO_SCH5627_ID 0xC6 /* Chipset ID */
#define SIO_SCH5636_ID 0xC7 /* Chipset ID */
-#define REGION_LENGTH 9
+#define REGION_LENGTH 10
#define SCH56XX_CMD_READ 0x02
#define SCH56XX_CMD_WRITE 0x03
+/* Watchdog registers */
+#define SCH56XX_REG_WDOG_PRESET 0x58B
+#define SCH56XX_REG_WDOG_CONTROL 0x58C
+#define SCH56XX_WDOG_TIME_BASE_SEC 0x01
+#define SCH56XX_REG_WDOG_OUTPUT_ENABLE 0x58E
+#define SCH56XX_WDOG_OUTPUT_ENABLE 0x02
+
+struct sch56xx_watchdog_data {
+ u16 addr;
+ u32 revision;
+ struct mutex *io_lock;
+ struct mutex watchdog_lock;
+ struct list_head list; /* member of the watchdog_data_list */
+ struct kref kref;
+ struct miscdevice watchdog_miscdev;
+ unsigned long watchdog_is_open;
+ char watchdog_name[10]; /* must be unique to avoid sysfs conflict */
+ char watchdog_expect_close;
+ u8 watchdog_preset;
+ u8 watchdog_control;
+ u8 watchdog_output_enable;
+};
+
static struct platform_device *sch56xx_pdev;
+/*
+ * Somewhat ugly :( global data pointer list with all sch56xx devices, so that
+ * we can find our device data as when using misc_register there is no other
+ * method to get to ones device data from the open fop.
+ */
+static LIST_HEAD(watchdog_data_list);
+/* Note this lock not only protect list access, but also data.kref access */
+static DEFINE_MUTEX(watchdog_data_mutex);
+
/* Super I/O functions */
static inline int superio_inb(int base, int reg)
{
}
EXPORT_SYMBOL(sch56xx_read_virtual_reg12);
+/*
+ * Watchdog routines
+ */
+
+/*
+ * Release our data struct when the platform device has been released *and*
+ * all references to our watchdog device are released.
+ */
+static void sch56xx_watchdog_release_resources(struct kref *r)
+{
+ struct sch56xx_watchdog_data *data =
+ container_of(r, struct sch56xx_watchdog_data, kref);
+ kfree(data);
+}
+
+static int watchdog_set_timeout(struct sch56xx_watchdog_data *data,
+ int timeout)
+{
+ int ret, resolution;
+ u8 control;
+
+ /* 1 second or 60 second resolution? */
+ if (timeout <= 255)
+ resolution = 1;
+ else
+ resolution = 60;
+
+ if (timeout < resolution || timeout > (resolution * 255))
+ return -EINVAL;
+
+ mutex_lock(&data->watchdog_lock);
+ if (!data->addr) {
+ ret = -ENODEV;
+ goto leave;
+ }
+
+ if (resolution == 1)
+ control = data->watchdog_control | SCH56XX_WDOG_TIME_BASE_SEC;
+ else
+ control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC;
+
+ if (data->watchdog_control != control) {
+ mutex_lock(data->io_lock);
+ ret = sch56xx_write_virtual_reg(data->addr,
+ SCH56XX_REG_WDOG_CONTROL,
+ control);
+ mutex_unlock(data->io_lock);
+ if (ret)
+ goto leave;
+
+ data->watchdog_control = control;
+ }
+
+ /*
+ * Remember new timeout value, but do not write as that (re)starts
+ * the watchdog countdown.
+ */
+ data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
+
+ ret = data->watchdog_preset * resolution;
+leave:
+ mutex_unlock(&data->watchdog_lock);
+ return ret;
+}
+
+static int watchdog_get_timeout(struct sch56xx_watchdog_data *data)
+{
+ int timeout;
+
+ mutex_lock(&data->watchdog_lock);
+ if (data->watchdog_control & SCH56XX_WDOG_TIME_BASE_SEC)
+ timeout = data->watchdog_preset;
+ else
+ timeout = data->watchdog_preset * 60;
+ mutex_unlock(&data->watchdog_lock);
+
+ return timeout;
+}
+
+static int watchdog_start(struct sch56xx_watchdog_data *data)
+{
+ int ret;
+ u8 val;
+
+ mutex_lock(&data->watchdog_lock);
+ if (!data->addr) {
+ ret = -ENODEV;
+ goto leave_unlock_watchdog;
+ }
+
+ /*
+ * The sch56xx's watchdog cannot really be started / stopped
+ * it is always running, but we can avoid the timer expiring
+ * from causing a system reset by clearing the output enable bit.
+ *
+ * The sch56xx's watchdog will set the watchdog event bit, bit 0
+ * of the second interrupt source register (at base-address + 9),
+ * when the timer expires.
+ *
+ * This will only cause a system reset if the 0-1 flank happens when
+ * output enable is true. Setting output enable after the flank will
+ * not cause a reset, nor will the timer expiring a second time.
+ * This means we must clear the watchdog event bit in case it is set.
+ *
+ * The timer may still be running (after a recent watchdog_stop) and
+ * mere milliseconds away from expiring, so the timer must be reset
+ * first!
+ */
+
+ mutex_lock(data->io_lock);
+
+ /* 1. Reset the watchdog countdown counter */
+ ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
+ data->watchdog_preset);
+ if (ret)
+ goto leave;
+
+ /* 2. Enable output (if not already enabled) */
+ if (!(data->watchdog_output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
+ val = data->watchdog_output_enable |
+ SCH56XX_WDOG_OUTPUT_ENABLE;
+ ret = sch56xx_write_virtual_reg(data->addr,
+ SCH56XX_REG_WDOG_OUTPUT_ENABLE,
+ val);
+ if (ret)
+ goto leave;
+
+ data->watchdog_output_enable = val;
+ }
+
+ /* 3. Clear the watchdog event bit if set */
+ val = inb(data->addr + 9);
+ if (val & 0x01)
+ outb(0x01, data->addr + 9);
+
+leave:
+ mutex_unlock(data->io_lock);
+leave_unlock_watchdog:
+ mutex_unlock(&data->watchdog_lock);
+ return ret;
+}
+
+static int watchdog_trigger(struct sch56xx_watchdog_data *data)
+{
+ int ret;
+
+ mutex_lock(&data->watchdog_lock);
+ if (!data->addr) {
+ ret = -ENODEV;
+ goto leave;
+ }
+
+ /* Reset the watchdog countdown counter */
+ mutex_lock(data->io_lock);
+ ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
+ data->watchdog_preset);
+ mutex_unlock(data->io_lock);
+leave:
+ mutex_unlock(&data->watchdog_lock);
+ return ret;
+}
+
+static int watchdog_stop_unlocked(struct sch56xx_watchdog_data *data)
+{
+ int ret = 0;
+ u8 val;
+
+ if (!data->addr)
+ return -ENODEV;
+
+ if (data->watchdog_output_enable & SCH56XX_WDOG_OUTPUT_ENABLE) {
+ val = data->watchdog_output_enable &
+ ~SCH56XX_WDOG_OUTPUT_ENABLE;
+ mutex_lock(data->io_lock);
+ ret = sch56xx_write_virtual_reg(data->addr,
+ SCH56XX_REG_WDOG_OUTPUT_ENABLE,
+ val);
+ mutex_unlock(data->io_lock);
+ if (ret)
+ return ret;
+
+ data->watchdog_output_enable = val;
+ }
+
+ return ret;
+}
+
+static int watchdog_stop(struct sch56xx_watchdog_data *data)
+{
+ int ret;
+
+ mutex_lock(&data->watchdog_lock);
+ ret = watchdog_stop_unlocked(data);
+ mutex_unlock(&data->watchdog_lock);
+
+ return ret;
+}
+
+static int watchdog_release(struct inode *inode, struct file *filp)
+{
+ struct sch56xx_watchdog_data *data = filp->private_data;
+
+ if (data->watchdog_expect_close) {
+ watchdog_stop(data);
+ data->watchdog_expect_close = 0;
+ } else {
+ watchdog_trigger(data);
+ pr_crit("unexpected close, not stopping watchdog!\n");
+ }
+
+ clear_bit(0, &data->watchdog_is_open);
+
+ mutex_lock(&watchdog_data_mutex);
+ kref_put(&data->kref, sch56xx_watchdog_release_resources);
+ mutex_unlock(&watchdog_data_mutex);
+
+ return 0;
+}
+
+static int watchdog_open(struct inode *inode, struct file *filp)
+{
+ struct sch56xx_watchdog_data *pos, *data = NULL;
+ int ret, watchdog_is_open;
+
+ /*
+ * We get called from drivers/char/misc.c with misc_mtx hold, and we
+ * call misc_register() from sch56xx_watchdog_probe() with
+ * watchdog_data_mutex hold, as misc_register() takes the misc_mtx
+ * lock, this is a possible deadlock, so we use mutex_trylock here.
+ */
+ if (!mutex_trylock(&watchdog_data_mutex))
+ return -ERESTARTSYS;
+ list_for_each_entry(pos, &watchdog_data_list, list) {
+ if (pos->watchdog_miscdev.minor == iminor(inode)) {
+ data = pos;
+ break;
+ }
+ }
+ /* Note we can never not have found data, so we don't check for this */
+ watchdog_is_open = test_and_set_bit(0, &data->watchdog_is_open);
+ if (!watchdog_is_open)
+ kref_get(&data->kref);
+ mutex_unlock(&watchdog_data_mutex);
+
+ if (watchdog_is_open)
+ return -EBUSY;
+
+ filp->private_data = data;
+
+ /* Start the watchdog */
+ ret = watchdog_start(data);
+ if (ret) {
+ watchdog_release(inode, filp);
+ return ret;
+ }
+
+ return nonseekable_open(inode, filp);
+}
+
+static ssize_t watchdog_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *offset)
+{
+ int ret;
+ struct sch56xx_watchdog_data *data = filp->private_data;
+
+ if (count) {
+ if (!nowayout) {
+ size_t i;
+
+ /* Clear it in case it was set with a previous write */
+ data->watchdog_expect_close = 0;
+
+ for (i = 0; i != count; i++) {
+ char c;
+ if (get_user(c, buf + i))
+ return -EFAULT;
+ if (c == 'V')
+ data->watchdog_expect_close = 1;
+ }
+ }
+ ret = watchdog_trigger(data);
+ if (ret)
+ return ret;
+ }
+ return count;
+}
+
+static long watchdog_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ struct watchdog_info ident = {
+ .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
+ .identity = "sch56xx watchdog"
+ };
+ int i, ret = 0;
+ struct sch56xx_watchdog_data *data = filp->private_data;
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ ident.firmware_version = data->revision;
+ if (!nowayout)
+ ident.options |= WDIOF_MAGICCLOSE;
+ if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
+ ret = -EFAULT;
+ break;
+
+ case WDIOC_GETSTATUS:
+ case WDIOC_GETBOOTSTATUS:
+ ret = put_user(0, (int __user *)arg);
+ break;
+
+ case WDIOC_KEEPALIVE:
+ ret = watchdog_trigger(data);
+ break;
+
+ case WDIOC_GETTIMEOUT:
+ i = watchdog_get_timeout(data);
+ ret = put_user(i, (int __user *)arg);
+ break;
+
+ case WDIOC_SETTIMEOUT:
+ if (get_user(i, (int __user *)arg)) {
+ ret = -EFAULT;
+ break;
+ }
+ ret = watchdog_set_timeout(data, i);
+ if (ret >= 0)
+ ret = put_user(ret, (int __user *)arg);
+ break;
+
+ case WDIOC_SETOPTIONS:
+ if (get_user(i, (int __user *)arg)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ if (i & WDIOS_DISABLECARD)
+ ret = watchdog_stop(data);
+ else if (i & WDIOS_ENABLECARD)
+ ret = watchdog_trigger(data);
+ else
+ ret = -EINVAL;
+ break;
+
+ default:
+ ret = -ENOTTY;
+ }
+ return ret;
+}
+
+static const struct file_operations watchdog_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .open = watchdog_open,
+ .release = watchdog_release,
+ .write = watchdog_write,
+ .unlocked_ioctl = watchdog_ioctl,
+};
+
+struct sch56xx_watchdog_data *sch56xx_watchdog_register(
+ u16 addr, u32 revision, struct mutex *io_lock, int check_enabled)
+{
+ struct sch56xx_watchdog_data *data;
+ int i, err, control, output_enable;
+ const int watchdog_minors[] = { WATCHDOG_MINOR, 212, 213, 214, 215 };
+
+ /* Cache the watchdog registers */
+ mutex_lock(io_lock);
+ control =
+ sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL);
+ output_enable =
+ sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE);
+ mutex_unlock(io_lock);
+
+ if (control < 0)
+ return NULL;
+ if (output_enable < 0)
+ return NULL;
+ if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
+ pr_warn("Watchdog not enabled by BIOS, not registering\n");
+ return NULL;
+ }
+
+ data = kzalloc(sizeof(struct sch56xx_watchdog_data), GFP_KERNEL);
+ if (!data)
+ return NULL;
+
+ data->addr = addr;
+ data->revision = revision;
+ data->io_lock = io_lock;
+ data->watchdog_control = control;
+ data->watchdog_output_enable = output_enable;
+ mutex_init(&data->watchdog_lock);
+ INIT_LIST_HEAD(&data->list);
+ kref_init(&data->kref);
+
+ err = watchdog_set_timeout(data, 60);
+ if (err < 0)
+ goto error;
+
+ /*
+ * We take the data_mutex lock early so that watchdog_open() cannot
+ * run when misc_register() has completed, but we've not yet added
+ * our data to the watchdog_data_list.
+ */
+ mutex_lock(&watchdog_data_mutex);
+ for (i = 0; i < ARRAY_SIZE(watchdog_minors); i++) {
+ /* Register our watchdog part */
+ snprintf(data->watchdog_name, sizeof(data->watchdog_name),
+ "watchdog%c", (i == 0) ? '\0' : ('0' + i));
+ data->watchdog_miscdev.name = data->watchdog_name;
+ data->watchdog_miscdev.fops = &watchdog_fops;
+ data->watchdog_miscdev.minor = watchdog_minors[i];
+ err = misc_register(&data->watchdog_miscdev);
+ if (err == -EBUSY)
+ continue;
+ if (err)
+ break;
+
+ list_add(&data->list, &watchdog_data_list);
+ pr_info("Registered /dev/%s chardev major 10, minor: %d\n",
+ data->watchdog_name, watchdog_minors[i]);
+ break;
+ }
+ mutex_unlock(&watchdog_data_mutex);
+
+ if (err) {
+ pr_err("Registering watchdog chardev: %d\n", err);
+ goto error;
+ }
+ if (i == ARRAY_SIZE(watchdog_minors)) {
+ pr_warn("Couldn't register watchdog (no free minor)\n");
+ goto error;
+ }
+
+ return data;
+
+error:
+ kfree(data);
+ return NULL;
+}
+EXPORT_SYMBOL(sch56xx_watchdog_register);
+
+void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data)
+{
+ mutex_lock(&watchdog_data_mutex);
+ misc_deregister(&data->watchdog_miscdev);
+ list_del(&data->list);
+ mutex_unlock(&watchdog_data_mutex);
+
+ mutex_lock(&data->watchdog_lock);
+ if (data->watchdog_is_open) {
+ pr_warn("platform device unregistered with watchdog "
+ "open! Stopping watchdog.\n");
+ watchdog_stop_unlocked(data);
+ }
+ /* Tell the wdog start/stop/trigger functions our dev is gone */
+ data->addr = 0;
+ data->io_lock = NULL;
+ mutex_unlock(&data->watchdog_lock);
+
+ mutex_lock(&watchdog_data_mutex);
+ kref_put(&data->kref, sch56xx_watchdog_release_resources);
+ mutex_unlock(&watchdog_data_mutex);
+}
+EXPORT_SYMBOL(sch56xx_watchdog_unregister);
+
+/*
+ * platform dev find, add and remove functions
+ */
+
static int __init sch56xx_find(int sioaddr, unsigned short *address,
const char **name)
{
projects / platform / kernel / linux-stable.git / commitdiff