/***************************************************************************
* 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 *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#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_REG_LDSEL 0x07 /* Logical device select */
#define SIO_REG_DEVID 0x20 /* Device ID */
#define SIO_REG_ENABLE 0x30 /* Logical device enable */
#define SIO_REG_ADDR 0x66 /* Logical device address (2 bytes) */
#define SIO_SCH5627_ID 0xC6 /* Chipset ID */
#define SIO_SCH5636_ID 0xC7 /* Chipset ID */
#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)
{
outb(reg, base);
return inb(base + 1);
}
static inline int superio_enter(int base)
{
/* Don't step on other drivers' I/O space by accident */
if (!request_muxed_region(base, 2, "sch56xx")) {
pr_err("I/O address 0x%04x already in use\n", base);
return -EBUSY;
}
outb(SIO_UNLOCK_KEY, base);
return 0;
}
static inline void superio_select(int base, int ld)
{
outb(SIO_REG_LDSEL, base);
outb(ld, base + 1);
}
static inline void superio_exit(int base)
{
outb(SIO_LOCK_KEY, base);
release_region(base, 2);
}
static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
{
u8 val;
int i;
/*
* According to SMSC for the commands we use the maximum time for
* the EM to respond is 15 ms, but testing shows in practice it
* responds within 15-32 reads, so we first busy poll, and if
* that fails sleep a bit and try again until we are way past
* the 15 ms maximum response time.
*/
const int max_busy_polls = 64;
const int max_lazy_polls = 32;
/* (Optional) Write-Clear the EC to Host Mailbox Register */
val = inb(addr + 1);
outb(val, addr + 1);
/* Set Mailbox Address Pointer to first location in Region 1 */
outb(0x00, addr + 2);
outb(0x80, addr + 3);
/* Write Request Packet Header */
outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */
/* Write Value field */
if (cmd == SCH56XX_CMD_WRITE)
outb(v, addr + 4);
/* Write Address field */
outb(reg & 0xff, addr + 6);
outb(reg >> 8, addr + 7);
/* Execute the Random Access Command */
outb(0x01, addr); /* Write 01h to the Host-to-EC register */
/* EM Interface Polling "Algorithm" */
for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
if (i >= max_busy_polls)
msleep(1);
/* Read Interrupt source Register */
val = inb(addr + 8);
/* Write Clear the interrupt source bits */
if (val)
outb(val, addr + 8);
/* Command Completed ? */
if (val & 0x01)
break;
}
if (i == max_busy_polls + max_lazy_polls) {
pr_err("Max retries exceeded reading virtual "
"register 0x%04hx (%d)\n", reg, 1);
return -EIO;
}
/*
* According to SMSC we may need to retry this, but sofar I've always
* seen this succeed in 1 try.
*/
for (i = 0; i < max_busy_polls; i++) {
/* Read EC-to-Host Register */
val = inb(addr + 1);
/* Command Completed ? */
if (val == 0x01)
break;
if (i == 0)
pr_warn("EC reports: 0x%02x reading virtual register "
"0x%04hx\n", (unsigned int)val, reg);
}
if (i == max_busy_polls) {
pr_err("Max retries exceeded reading virtual "
"register 0x%04hx (%d)\n", reg, 2);
return -EIO;
}
/*
* According to the SMSC app note we should now do:
*
* Set Mailbox Address Pointer to first location in Region 1 *
* outb(0x00, addr + 2);
* outb(0x80, addr + 3);
*
* But if we do that things don't work, so let's not.
*/
/* Read Value field */
if (cmd == SCH56XX_CMD_READ)
return inb(addr + 4);
return 0;
}
int sch56xx_read_virtual_reg(u16 addr, u16 reg)
{
return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
}
EXPORT_SYMBOL(sch56xx_read_virtual_reg);
int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
{
return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
}
EXPORT_SYMBOL(sch56xx_write_virtual_reg);
int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
{
int lsb, msb;
/* Read LSB first, this will cause the matching MSB to be latched */
lsb = sch56xx_read_virtual_reg(addr, reg);
if (lsb < 0)
return lsb;
msb = sch56xx_read_virtual_reg(addr, reg + 1);
if (msb < 0)
return msb;
return lsb | (msb << 8);
}
EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
int high_nibble)
{
int msb, lsn;
/* Read MSB first, this will cause the matching LSN to be latched */
msb = sch56xx_read_virtual_reg(addr, msb_reg);
if (msb < 0)
return msb;
lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
if (lsn < 0)
return lsn;
if (high_nibble)
return (msb << 4) | (lsn >> 4);
else
return (msb << 4) | (lsn & 0x0f);
}
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)
{
u8 devid;
int err;
err = superio_enter(sioaddr);
if (err)
return err;
devid = superio_inb(sioaddr, SIO_REG_DEVID);
switch (devid) {
case SIO_SCH5627_ID:
*name = "sch5627";
break;
case SIO_SCH5636_ID:
*name = "sch5636";
break;
default:
pr_debug("Unsupported device id: 0x%02x\n",
(unsigned int)devid);
err = -ENODEV;
goto exit;
}
superio_select(sioaddr, SIO_SCH56XX_LD_EM);
if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
pr_warn("Device not activated\n");
err = -ENODEV;
goto exit;
}
/*
* Warning the order of the low / high byte is the other way around
* as on most other superio devices!!
*/
*address = superio_inb(sioaddr, SIO_REG_ADDR) |
superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
if (*address == 0) {
pr_warn("Base address not set\n");
err = -ENODEV;
goto exit;
}
exit:
superio_exit(sioaddr);
return err;
}
static int __init sch56xx_device_add(unsigned short address, const char *name)
{
struct resource res = {
.start = address,
.end = address + REGION_LENGTH - 1,
.flags = IORESOURCE_IO,
};
int err;
sch56xx_pdev = platform_device_alloc(name, address);
if (!sch56xx_pdev)
return -ENOMEM;
res.name = sch56xx_pdev->name;
err = acpi_check_resource_conflict(&res);
if (err)
goto exit_device_put;
err = platform_device_add_resources(sch56xx_pdev, &res, 1);
if (err) {
pr_err("Device resource addition failed\n");
goto exit_device_put;
}
err = platform_device_add(sch56xx_pdev);
if (err) {
pr_err("Device addition failed\n");
goto exit_device_put;
}
return 0;
exit_device_put:
platform_device_put(sch56xx_pdev);
return err;
}
static int __init sch56xx_init(void)
{
int err;
unsigned short address;
const char *name;
err = sch56xx_find(0x4e, &address, &name);
if (err)
err = sch56xx_find(0x2e, &address, &name);
if (err)
return err;
return sch56xx_device_add(address, name);
}
static void __exit sch56xx_exit(void)
{
platform_device_unregister(sch56xx_pdev);
}
MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_LICENSE("GPL");
module_init(sch56xx_init);
module_exit(sch56xx_exit);