[linux-2.6-block.git] / drivers / hwmon / sch56xx-common.c

/***************************************************************************
 *   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;
	struct mutex *io_lock;
	struct watchdog_info wdinfo;
	struct watchdog_device wddev;
	u8 watchdog_preset;
	u8 watchdog_control;
	u8 watchdog_output_enable;
};

static struct platform_device *sch56xx_pdev;

/* 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
 */

static int watchdog_set_timeout(struct watchdog_device *wddev,
				unsigned int timeout)
{
	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
	unsigned int resolution;
	u8 control;
	int ret;

	/* 1 second or 60 second resolution? */
	if (timeout <= 255)
		resolution = 1;
	else
		resolution = 60;

	if (timeout < resolution || timeout > (resolution * 255))
		return -EINVAL;

	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)
			return ret;

		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);
	wddev->timeout = data->watchdog_preset * resolution;

	return 0;
}

static int watchdog_start(struct watchdog_device *wddev)
{
	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
	int ret;
	u8 val;

	/*
	 * 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);
	return ret;
}

static int watchdog_trigger(struct watchdog_device *wddev)
{
	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
	int ret;

	/* 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);

	return ret;
}

static int watchdog_stop(struct watchdog_device *wddev)
{
	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
	int ret = 0;
	u8 val;

	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 const struct watchdog_ops watchdog_ops = {
	.owner		= THIS_MODULE,
	.start		= watchdog_start,
	.stop		= watchdog_stop,
	.ping		= watchdog_trigger,
	.set_timeout	= watchdog_set_timeout,
};

struct sch56xx_watchdog_data *sch56xx_watchdog_register(struct device *parent,
	u16 addr, u32 revision, struct mutex *io_lock, int check_enabled)
{
	struct sch56xx_watchdog_data *data;
	int err, control, output_enable;

	/* 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->io_lock = io_lock;

	strlcpy(data->wdinfo.identity, "sch56xx watchdog",
		sizeof(data->wdinfo.identity));
	data->wdinfo.firmware_version = revision;
	data->wdinfo.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT;
	if (!nowayout)
		data->wdinfo.options |= WDIOF_MAGICCLOSE;

	data->wddev.info = &data->wdinfo;
	data->wddev.ops = &watchdog_ops;
	data->wddev.parent = parent;
	data->wddev.timeout = 60;
	data->wddev.min_timeout = 1;
	data->wddev.max_timeout = 255 * 60;
	if (nowayout)
		data->wddev.status |= WDOG_NO_WAY_OUT;
	if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)
		data->wddev.status |= WDOG_ACTIVE;

	/* Since the watchdog uses a downcounter there is no register to read
	   the BIOS set timeout from (if any was set at all) ->
	   Choose a preset which will give us a 1 minute timeout */
	if (control & SCH56XX_WDOG_TIME_BASE_SEC)
		data->watchdog_preset = 60; /* seconds */
	else
		data->watchdog_preset = 1; /* minute */

	data->watchdog_control = control;
	data->watchdog_output_enable = output_enable;

	watchdog_set_drvdata(&data->wddev, data);
	err = watchdog_register_device(&data->wddev);
	if (err) {
		pr_err("Registering watchdog chardev: %d\n", err);
		kfree(data);
		return NULL;
	}

	return data;
}
EXPORT_SYMBOL(sch56xx_watchdog_register);

void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data)
{
	watchdog_unregister_device(&data->wddev);
	kfree(data);
}
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);
Commit	Line	Data
28ff2f7a	1	/***************************************************************************
312869ec	2	* Copyright (C) 2010-2012 Hans de Goede <hdegoede@redhat.com> *
28ff2f7a HG	3	* *
	4	* This program is free software; you can redistribute it and/or modify *
	5	* it under the terms of the GNU General Public License as published by *
	6	* the Free Software Foundation; either version 2 of the License, or *
	7	* (at your option) any later version. *
	8	* *
	9	* This program is distributed in the hope that it will be useful, *
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of *
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
	12	* GNU General Public License for more details. *
	13	* *
	14	* You should have received a copy of the GNU General Public License *
	15	* along with this program; if not, write to the *
	16	* Free Software Foundation, Inc., *
	17	* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
	18	***************************************************************************/
	19
	20	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	21
	22	#include <linux/module.h>
	23	#include <linux/init.h>
	24	#include <linux/platform_device.h>
	25	#include <linux/err.h>
	26	#include <linux/io.h>
	27	#include <linux/acpi.h>
	28	#include <linux/delay.h>
312869ec HG	29	#include <linux/fs.h>
	30	#include <linux/watchdog.h>
	31	#include <linux/miscdevice.h>
	32	#include <linux/uaccess.h>
	33	#include <linux/kref.h>
	34	#include <linux/slab.h>
28ff2f7a HG	35	#include "sch56xx-common.h"
28ff2f7a HG	36
312869ec HG	37	/* Insmod parameters */
	38	static int nowayout = WATCHDOG_NOWAYOUT;
	39	module_param(nowayout, int, 0);
	40	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	41	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	42
28ff2f7a HG	43	#define SIO_SCH56XX_LD_EM 0x0C /* Embedded uController Logical Dev */
	44	#define SIO_UNLOCK_KEY 0x55 /* Key to enable Super-I/O */
	45	#define SIO_LOCK_KEY 0xAA /* Key to disable Super-I/O */
	46
	47	#define SIO_REG_LDSEL 0x07 /* Logical device select */
	48	#define SIO_REG_DEVID 0x20 /* Device ID */
	49	#define SIO_REG_ENABLE 0x30 /* Logical device enable */
	50	#define SIO_REG_ADDR 0x66 /* Logical device address (2 bytes) */
	51
	52	#define SIO_SCH5627_ID 0xC6 /* Chipset ID */
0772a640	53	#define SIO_SCH5636_ID 0xC7 /* Chipset ID */
28ff2f7a	54
312869ec	55	#define REGION_LENGTH 10
28ff2f7a HG	56
	57	#define SCH56XX_CMD_READ 0x02
	58	#define SCH56XX_CMD_WRITE 0x03
	59
312869ec HG	60	/* Watchdog registers */
	61	#define SCH56XX_REG_WDOG_PRESET 0x58B
	62	#define SCH56XX_REG_WDOG_CONTROL 0x58C
	63	#define SCH56XX_WDOG_TIME_BASE_SEC 0x01
	64	#define SCH56XX_REG_WDOG_OUTPUT_ENABLE 0x58E
	65	#define SCH56XX_WDOG_OUTPUT_ENABLE 0x02
	66
	67	struct sch56xx_watchdog_data {
	68	u16 addr;
312869ec	69	struct mutex *io_lock;
fb551405 HG	70	struct watchdog_info wdinfo;
fb551405 HG	71	struct watchdog_device wddev;
312869ec HG	72	u8 watchdog_preset;
	73	u8 watchdog_control;
	74	u8 watchdog_output_enable;
	75	};
	76
28ff2f7a HG	77	static struct platform_device *sch56xx_pdev;
	78
	79	/* Super I/O functions */
	80	static inline int superio_inb(int base, int reg)
	81	{
	82	outb(reg, base);
	83	return inb(base + 1);
	84	}
	85
	86	static inline int superio_enter(int base)
	87	{
	88	/* Don't step on other drivers' I/O space by accident */
	89	if (!request_muxed_region(base, 2, "sch56xx")) {
	90	pr_err("I/O address 0x%04x already in use\n", base);
	91	return -EBUSY;
	92	}
	93
	94	outb(SIO_UNLOCK_KEY, base);
	95
	96	return 0;
	97	}
	98
	99	static inline void superio_select(int base, int ld)
	100	{
	101	outb(SIO_REG_LDSEL, base);
	102	outb(ld, base + 1);
	103	}
	104
	105	static inline void superio_exit(int base)
	106	{
	107	outb(SIO_LOCK_KEY, base);
	108	release_region(base, 2);
	109	}
	110
	111	static int sch56xx_send_cmd(u16 addr, u8 cmd, u16 reg, u8 v)
	112	{
	113	u8 val;
	114	int i;
	115	/*
	116	* According to SMSC for the commands we use the maximum time for
	117	* the EM to respond is 15 ms, but testing shows in practice it
	118	* responds within 15-32 reads, so we first busy poll, and if
	119	* that fails sleep a bit and try again until we are way past
	120	* the 15 ms maximum response time.
	121	*/
	122	const int max_busy_polls = 64;
	123	const int max_lazy_polls = 32;
	124
	125	/* (Optional) Write-Clear the EC to Host Mailbox Register */
	126	val = inb(addr + 1);
	127	outb(val, addr + 1);
	128
	129	/* Set Mailbox Address Pointer to first location in Region 1 */
	130	outb(0x00, addr + 2);
	131	outb(0x80, addr + 3);
	132
	133	/* Write Request Packet Header */
	134	outb(cmd, addr + 4); /* VREG Access Type read:0x02 write:0x03 */
	135	outb(0x01, addr + 5); /* # of Entries: 1 Byte (8-bit) */
	136	outb(0x04, addr + 2); /* Mailbox AP to first data entry loc. */
	137
	138	/* Write Value field */
	139	if (cmd == SCH56XX_CMD_WRITE)
	140	outb(v, addr + 4);
141
142	/* Write Address field */
143	outb(reg & 0xff, addr + 6);
144	outb(reg >> 8, addr + 7);
145
146	/* Execute the Random Access Command */
147	outb(0x01, addr); /* Write 01h to the Host-to-EC register */
148
149	/* EM Interface Polling "Algorithm" */
150	for (i = 0; i < max_busy_polls + max_lazy_polls; i++) {
151	if (i >= max_busy_polls)
152	msleep(1);
153	/* Read Interrupt source Register */
154	val = inb(addr + 8);
155	/* Write Clear the interrupt source bits */
156	if (val)
157	outb(val, addr + 8);
158	/* Command Completed ? */
159	if (val & 0x01)
160	break;
161	}
162	if (i == max_busy_polls + max_lazy_polls) {
163	pr_err("Max retries exceeded reading virtual "
164	"register 0x%04hx (%d)\n", reg, 1);
165	return -EIO;
166	}
167
168	/*
169	* According to SMSC we may need to retry this, but sofar I've always
170	* seen this succeed in 1 try.
171	*/
172	for (i = 0; i < max_busy_polls; i++) {
173	/* Read EC-to-Host Register */
174	val = inb(addr + 1);
175	/* Command Completed ? */
176	if (val == 0x01)
177	break;
178
179	if (i == 0)
180	pr_warn("EC reports: 0x%02x reading virtual register "
181	"0x%04hx\n", (unsigned int)val, reg);
182	}
183	if (i == max_busy_polls) {
184	pr_err("Max retries exceeded reading virtual "
185	"register 0x%04hx (%d)\n", reg, 2);
186	return -EIO;
187	}
188
189	/*
190	* According to the SMSC app note we should now do:
191	*
192	* Set Mailbox Address Pointer to first location in Region 1 *
193	* outb(0x00, addr + 2);
194	* outb(0x80, addr + 3);
195	*
196	* But if we do that things don't work, so let's not.
197	*/
198
199	/* Read Value field */
200	if (cmd == SCH56XX_CMD_READ)
201	return inb(addr + 4);
202
203	return 0;
204	}
205
206	int sch56xx_read_virtual_reg(u16 addr, u16 reg)
207	{
208	return sch56xx_send_cmd(addr, SCH56XX_CMD_READ, reg, 0);
209	}
210	EXPORT_SYMBOL(sch56xx_read_virtual_reg);
211
212	int sch56xx_write_virtual_reg(u16 addr, u16 reg, u8 val)
213	{
214	return sch56xx_send_cmd(addr, SCH56XX_CMD_WRITE, reg, val);
215	}
216	EXPORT_SYMBOL(sch56xx_write_virtual_reg);
217
218	int sch56xx_read_virtual_reg16(u16 addr, u16 reg)
219	{
220	int lsb, msb;
221
222	/* Read LSB first, this will cause the matching MSB to be latched */
223	lsb = sch56xx_read_virtual_reg(addr, reg);
224	if (lsb < 0)
225	return lsb;
226
227	msb = sch56xx_read_virtual_reg(addr, reg + 1);
228	if (msb < 0)
229	return msb;
230
231	return lsb \| (msb << 8);
232	}
233	EXPORT_SYMBOL(sch56xx_read_virtual_reg16);
234
235	int sch56xx_read_virtual_reg12(u16 addr, u16 msb_reg, u16 lsn_reg,
236	int high_nibble)
237	{
238	int msb, lsn;
239
240	/* Read MSB first, this will cause the matching LSN to be latched */
241	msb = sch56xx_read_virtual_reg(addr, msb_reg);
242	if (msb < 0)
243	return msb;
244
245	lsn = sch56xx_read_virtual_reg(addr, lsn_reg);
246	if (lsn < 0)
247	return lsn;
248
249	if (high_nibble)
250	return (msb << 4) \| (lsn >> 4);
251	else
252	return (msb << 4) \| (lsn & 0x0f);
253	}
254	EXPORT_SYMBOL(sch56xx_read_virtual_reg12);
255
312869ec HG	256	/*
	257	* Watchdog routines
	258	*/
	259
fb551405 HG	260	static int watchdog_set_timeout(struct watchdog_device *wddev,
fb551405 HG	261	unsigned int timeout)
312869ec	262	{
fb551405 HG	263	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
fb551405 HG	264	unsigned int resolution;
312869ec	265	u8 control;
fb551405	266	int ret;
312869ec HG	267
	268	/* 1 second or 60 second resolution? */
	269	if (timeout <= 255)
	270	resolution = 1;
	271	else
	272	resolution = 60;
	273
	274	if (timeout < resolution \|\| timeout > (resolution * 255))
	275	return -EINVAL;
	276
312869ec HG	277	if (resolution == 1)
	278	control = data->watchdog_control \| SCH56XX_WDOG_TIME_BASE_SEC;
	279	else
	280	control = data->watchdog_control & ~SCH56XX_WDOG_TIME_BASE_SEC;
	281
	282	if (data->watchdog_control != control) {
	283	mutex_lock(data->io_lock);
	284	ret = sch56xx_write_virtual_reg(data->addr,
	285	SCH56XX_REG_WDOG_CONTROL,
	286	control);
	287	mutex_unlock(data->io_lock);
	288	if (ret)
fb551405	289	return ret;
312869ec HG	290
	291	data->watchdog_control = control;
	292	}
	293
	294	/*
	295	* Remember new timeout value, but do not write as that (re)starts
	296	* the watchdog countdown.
	297	*/
	298	data->watchdog_preset = DIV_ROUND_UP(timeout, resolution);
fb551405	299	wddev->timeout = data->watchdog_preset * resolution;
312869ec	300
fb551405	301	return 0;
312869ec HG	302	}
312869ec HG	303
fb551405	304	static int watchdog_start(struct watchdog_device *wddev)
312869ec	305	{
fb551405	306	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
312869ec HG	307	int ret;
	308	u8 val;
	309
312869ec HG	310	/*
	311	* The sch56xx's watchdog cannot really be started / stopped
	312	* it is always running, but we can avoid the timer expiring
	313	* from causing a system reset by clearing the output enable bit.
	314	*
	315	* The sch56xx's watchdog will set the watchdog event bit, bit 0
	316	* of the second interrupt source register (at base-address + 9),
	317	* when the timer expires.
	318	*
	319	* This will only cause a system reset if the 0-1 flank happens when
	320	* output enable is true. Setting output enable after the flank will
	321	* not cause a reset, nor will the timer expiring a second time.
	322	* This means we must clear the watchdog event bit in case it is set.
	323	*
	324	* The timer may still be running (after a recent watchdog_stop) and
	325	* mere milliseconds away from expiring, so the timer must be reset
	326	* first!
	327	*/
	328
	329	mutex_lock(data->io_lock);
	330
	331	/* 1. Reset the watchdog countdown counter */
	332	ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
	333	data->watchdog_preset);
	334	if (ret)
	335	goto leave;
	336
	337	/* 2. Enable output (if not already enabled) */
	338	if (!(data->watchdog_output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
	339	val = data->watchdog_output_enable \|
	340	SCH56XX_WDOG_OUTPUT_ENABLE;
	341	ret = sch56xx_write_virtual_reg(data->addr,
	342	SCH56XX_REG_WDOG_OUTPUT_ENABLE,
	343	val);
	344	if (ret)
	345	goto leave;
	346
	347	data->watchdog_output_enable = val;
	348	}
	349
	350	/* 3. Clear the watchdog event bit if set */
	351	val = inb(data->addr + 9);
	352	if (val & 0x01)
	353	outb(0x01, data->addr + 9);
	354
	355	leave:
	356	mutex_unlock(data->io_lock);
312869ec HG	357	return ret;
	358	}
	359
fb551405	360	static int watchdog_trigger(struct watchdog_device *wddev)
312869ec	361	{
fb551405	362	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
312869ec HG	363	int ret;
312869ec HG	364
312869ec HG	365	/* Reset the watchdog countdown counter */
	366	mutex_lock(data->io_lock);
	367	ret = sch56xx_write_virtual_reg(data->addr, SCH56XX_REG_WDOG_PRESET,
	368	data->watchdog_preset);
	369	mutex_unlock(data->io_lock);
fb551405	370
312869ec HG	371	return ret;
	372	}
	373
fb551405	374	static int watchdog_stop(struct watchdog_device *wddev)
312869ec	375	{
fb551405	376	struct sch56xx_watchdog_data *data = watchdog_get_drvdata(wddev);
312869ec HG	377	int ret = 0;
	378	u8 val;
	379
312869ec HG	380	if (data->watchdog_output_enable & SCH56XX_WDOG_OUTPUT_ENABLE) {
	381	val = data->watchdog_output_enable &
	382	~SCH56XX_WDOG_OUTPUT_ENABLE;
	383	mutex_lock(data->io_lock);
	384	ret = sch56xx_write_virtual_reg(data->addr,
	385	SCH56XX_REG_WDOG_OUTPUT_ENABLE,
	386	val);
	387	mutex_unlock(data->io_lock);
	388	if (ret)
	389	return ret;
	390
	391	data->watchdog_output_enable = val;
	392	}
	393
	394	return ret;
	395	}
	396
fb551405 HG	397	static const struct watchdog_ops watchdog_ops = {
	398	.owner = THIS_MODULE,
	399	.start = watchdog_start,
	400	.stop = watchdog_stop,
	401	.ping = watchdog_trigger,
	402	.set_timeout = watchdog_set_timeout,
312869ec HG	403	};
312869ec HG	404
fb551405	405	struct sch56xx_watchdog_data sch56xx_watchdog_register(struct device parent,
312869ec HG	406	u16 addr, u32 revision, struct mutex *io_lock, int check_enabled)
	407	{
	408	struct sch56xx_watchdog_data *data;
fb551405	409	int err, control, output_enable;
312869ec HG	410
	411	/* Cache the watchdog registers */
	412	mutex_lock(io_lock);
	413	control =
	414	sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_CONTROL);
	415	output_enable =
	416	sch56xx_read_virtual_reg(addr, SCH56XX_REG_WDOG_OUTPUT_ENABLE);
	417	mutex_unlock(io_lock);
	418
	419	if (control < 0)
	420	return NULL;
	421	if (output_enable < 0)
	422	return NULL;
	423	if (check_enabled && !(output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)) {
	424	pr_warn("Watchdog not enabled by BIOS, not registering\n");
	425	return NULL;
	426	}
	427
	428	data = kzalloc(sizeof(struct sch56xx_watchdog_data), GFP_KERNEL);
	429	if (!data)
	430	return NULL;
	431
	432	data->addr = addr;
312869ec	433	data->io_lock = io_lock;
312869ec	434
fb551405 HG	435	strlcpy(data->wdinfo.identity, "sch56xx watchdog",
	436	sizeof(data->wdinfo.identity));
	437	data->wdinfo.firmware_version = revision;
	438	data->wdinfo.options = WDIOF_KEEPALIVEPING \| WDIOF_SETTIMEOUT;
	439	if (!nowayout)
	440	data->wdinfo.options \|= WDIOF_MAGICCLOSE;
	441
	442	data->wddev.info = &data->wdinfo;
	443	data->wddev.ops = &watchdog_ops;
	444	data->wddev.parent = parent;
	445	data->wddev.timeout = 60;
	446	data->wddev.min_timeout = 1;
	447	data->wddev.max_timeout = 255 * 60;
	448	if (nowayout)
	449	data->wddev.status \|= WDOG_NO_WAY_OUT;
	450	if (output_enable & SCH56XX_WDOG_OUTPUT_ENABLE)
	451	data->wddev.status \|= WDOG_ACTIVE;
	452
	453	/* Since the watchdog uses a downcounter there is no register to read
	454	the BIOS set timeout from (if any was set at all) ->
	455	Choose a preset which will give us a 1 minute timeout */
	456	if (control & SCH56XX_WDOG_TIME_BASE_SEC)
	457	data->watchdog_preset = 60; /* seconds */
	458	else
	459	data->watchdog_preset = 1; /* minute */
312869ec	460
fb551405 HG	461	data->watchdog_control = control;
fb551405 HG	462	data->watchdog_output_enable = output_enable;
312869ec	463
fb551405 HG	464	watchdog_set_drvdata(&data->wddev, data);
fb551405 HG	465	err = watchdog_register_device(&data->wddev);
312869ec HG	466	if (err) {
312869ec HG	467	pr_err("Registering watchdog chardev: %d\n", err);
fb551405 HG	468	kfree(data);
fb551405 HG	469	return NULL;
312869ec HG	470	}
	471
	472	return data;
312869ec HG	473	}
	474	EXPORT_SYMBOL(sch56xx_watchdog_register);
	475
	476	void sch56xx_watchdog_unregister(struct sch56xx_watchdog_data *data)
	477	{
fb551405 HG	478	watchdog_unregister_device(&data->wddev);
fb551405 HG	479	kfree(data);
312869ec HG	480	}
	481	EXPORT_SYMBOL(sch56xx_watchdog_unregister);
	482
	483	/*
	484	* platform dev find, add and remove functions
	485	*/
	486
28ff2f7a HG	487	static int __init sch56xx_find(int sioaddr, unsigned short *address,
	488	const char **name)
	489	{
	490	u8 devid;
	491	int err;
	492
	493	err = superio_enter(sioaddr);
	494	if (err)
	495	return err;
	496
	497	devid = superio_inb(sioaddr, SIO_REG_DEVID);
	498	switch (devid) {
	499	case SIO_SCH5627_ID:
	500	*name = "sch5627";
	501	break;
0772a640 HG	502	case SIO_SCH5636_ID:
	503	*name = "sch5636";
	504	break;
28ff2f7a HG	505	default:
	506	pr_debug("Unsupported device id: 0x%02x\n",
	507	(unsigned int)devid);
	508	err = -ENODEV;
	509	goto exit;
	510	}
	511
	512	superio_select(sioaddr, SIO_SCH56XX_LD_EM);
	513
	514	if (!(superio_inb(sioaddr, SIO_REG_ENABLE) & 0x01)) {
	515	pr_warn("Device not activated\n");
	516	err = -ENODEV;
	517	goto exit;
	518	}
	519
	520	/*
	521	* Warning the order of the low / high byte is the other way around
	522	* as on most other superio devices!!
	523	*/
	524	*address = superio_inb(sioaddr, SIO_REG_ADDR) \|
	525	superio_inb(sioaddr, SIO_REG_ADDR + 1) << 8;
	526	if (*address == 0) {
	527	pr_warn("Base address not set\n");
	528	err = -ENODEV;
	529	goto exit;
	530	}
	531
	532	exit:
	533	superio_exit(sioaddr);
	534	return err;
	535	}
	536
	537	static int __init sch56xx_device_add(unsigned short address, const char *name)
	538	{
	539	struct resource res = {
	540	.start = address,
	541	.end = address + REGION_LENGTH - 1,
	542	.flags = IORESOURCE_IO,
	543	};
	544	int err;
	545
	546	sch56xx_pdev = platform_device_alloc(name, address);
	547	if (!sch56xx_pdev)
	548	return -ENOMEM;
	549
	550	res.name = sch56xx_pdev->name;
	551	err = acpi_check_resource_conflict(&res);
	552	if (err)
	553	goto exit_device_put;
	554
	555	err = platform_device_add_resources(sch56xx_pdev, &res, 1);
	556	if (err) {
	557	pr_err("Device resource addition failed\n");
	558	goto exit_device_put;
	559	}
	560
	561	err = platform_device_add(sch56xx_pdev);
	562	if (err) {
	563	pr_err("Device addition failed\n");
	564	goto exit_device_put;
	565	}
	566
	567	return 0;
	568
569	exit_device_put:
570	platform_device_put(sch56xx_pdev);
571
572	return err;
573	}
574
575	static int __init sch56xx_init(void)
576	{
577	int err;
578	unsigned short address;
579	const char *name;
580
581	err = sch56xx_find(0x4e, &address, &name);
582	if (err)
583	err = sch56xx_find(0x2e, &address, &name);
584	if (err)
585	return err;
586
587	return sch56xx_device_add(address, name);
588	}
589
590	static void __exit sch56xx_exit(void)
591	{
592	platform_device_unregister(sch56xx_pdev);
593	}
594
595	MODULE_DESCRIPTION("SMSC SCH56xx Hardware Monitoring Common Code");
596	MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
597	MODULE_LICENSE("GPL");
598
599	module_init(sch56xx_init);
600	module_exit(sch56xx_exit);