1 files changed, 517 insertions, 2 deletions

diff --git a/drivers/hwmon/sch56xx-common.c b/drivers/hwmon/sch56xx-common.c
index fac32ee0b10e..ce52fc57d41d 100644
--- a/drivers/hwmon/sch56xx-common.c
+++ b/drivers/hwmon/sch56xx-common.c
@@ -1,5 +1,5 @@
 /***************************************************************************
- *   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  *
@@ -26,8 +26,20 @@
 #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 */
@@ -40,13 +52,45 @@
 #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)
 {
@@ -224,6 +268,477 @@ int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_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)
 {