ec.c

/*
 *  acpi_ec.c - ACPI Embedded Controller Driver ($Revision: 38 $)
 *
 *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <asm/io.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <acpi/actypes.h>

#define _COMPONENT		ACPI_EC_COMPONENT
ACPI_MODULE_NAME("acpi_ec")
#define ACPI_EC_COMPONENT		0x00100000
#define ACPI_EC_CLASS			"embedded_controller"
#define ACPI_EC_HID			"PNP0C09"
#define ACPI_EC_DRIVER_NAME		"ACPI Embedded Controller Driver"
#define ACPI_EC_DEVICE_NAME		"Embedded Controller"
#define ACPI_EC_FILE_INFO		"info"

#undef PREFIX
#define PREFIX				"ACPI: EC: "

/* EC status register */
#define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
#define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
#define ACPI_EC_FLAG_BURST	0x10	/* burst mode */
#define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */

/* EC commands */
#define ACPI_EC_COMMAND_READ	0x80
#define ACPI_EC_COMMAND_WRITE	0x81
#define ACPI_EC_BURST_ENABLE	0x82
#define ACPI_EC_BURST_DISABLE	0x83
#define ACPI_EC_COMMAND_QUERY	0x84

/* EC events */
enum {
	ACPI_EC_EVENT_OBF_1 = 1,	/* Output buffer full */
	ACPI_EC_EVENT_IBF_0,		/* Input buffer empty */
};

#define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
#define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */

enum {
	EC_INTR = 1,	/* Output buffer full */
	EC_POLL,	/* Input buffer empty */
};

static int acpi_ec_remove(struct acpi_device *device, int type);
static int acpi_ec_start(struct acpi_device *device);
static int acpi_ec_stop(struct acpi_device *device, int type);
static int acpi_ec_add(struct acpi_device *device);

static struct acpi_driver acpi_ec_driver = {
	.name = ACPI_EC_DRIVER_NAME,
	.class = ACPI_EC_CLASS,
	.ids = ACPI_EC_HID,
	.ops = {
		.add = acpi_ec_add,
		.remove = acpi_ec_remove,
		.start = acpi_ec_start,
		.stop = acpi_ec_stop,
		},
};

/* If we find an EC via the ECDT, we need to keep a ptr to its context */
struct acpi_ec {
	acpi_handle handle;
	unsigned long uid;
	unsigned long gpe;
	unsigned long command_addr;
	unsigned long data_addr;
	unsigned long global_lock;
	struct mutex lock;
	atomic_t query_pending;
	atomic_t leaving_burst;	/* 0 : No, 1 : Yes, 2: abort */
	wait_queue_head_t wait;
} *ec_ecdt;

/* External interfaces use first EC only, so remember */
static struct acpi_device *first_ec;
static int acpi_ec_mode = EC_INTR;

/* --------------------------------------------------------------------------
                             Transaction Management
   -------------------------------------------------------------------------- */

static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
{
	return inb(ec->command_addr);
}

static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
{
	return inb(ec->data_addr);
}

static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
{
	outb(command, ec->command_addr);
}

static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
{
	outb(data, ec->data_addr);
}

static int acpi_ec_check_status(struct acpi_ec *ec, u8 event)
{
	u8 status = acpi_ec_read_status(ec);
	switch (event) {
	case ACPI_EC_EVENT_OBF_1:
		if (status & ACPI_EC_FLAG_OBF)
			return 1;
		break;
	case ACPI_EC_EVENT_IBF_0:
		if (!(status & ACPI_EC_FLAG_IBF))
			return 1;
		break;
	default:
		break;
	}

	return 0;
}

static int acpi_ec_wait(struct acpi_ec *ec, u8 event)
{
	if (acpi_ec_mode == EC_POLL) {
		unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
		while (time_before(jiffies, delay)) {
			if (acpi_ec_check_status(ec, event))
				return 0;
		}
	} else {
		if (wait_event_timeout(ec->wait,
				       acpi_ec_check_status(ec, event),
				       msecs_to_jiffies(ACPI_EC_DELAY)) ||
		    acpi_ec_check_status(ec, event)) {
			return 0;
		} else {
			printk(KERN_ERR PREFIX "acpi_ec_wait timeout,"
			       " status = %d, expect_event = %d\n",
			     acpi_ec_read_status(ec), event);
		}
	}

	return -ETIME;
}

#ifdef ACPI_FUTURE_USAGE
/*
 * Note: samsung nv5000 doesn't work with ec burst mode.
 * http://bugzilla.kernel.org/show_bug.cgi?id=4980
 */
int acpi_ec_enter_burst_mode(struct acpi_ec *ec)
{
	u8 tmp = 0;
	u8 status = 0;


	status = acpi_ec_read_status(ec);
	if (status != -EINVAL && !(status & ACPI_EC_FLAG_BURST)) {
		status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0);
		if (status)
			goto end;
		acpi_ec_write_cmd(ec, ACPI_EC_BURST_ENABLE);
		status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1);
		tmp = acpi_ec_read_data(ec);
		if (tmp != 0x90) {	/* Burst ACK byte */