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 <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"


#define ACPI_EC_FLAG_OBF	0x01	/* Output buffer full */
#define ACPI_EC_FLAG_IBF	0x02	/* Input buffer full */
#define ACPI_EC_FLAG_SCI	0x20	/* EC-SCI occurred */

#define ACPI_EC_EVENT_OBF	0x01	/* Output buffer full */
#define ACPI_EC_EVENT_IBE	0x02	/* Input buffer empty */

#define ACPI_EC_UDELAY		100	/* Poll @ 100us increments */
#define ACPI_EC_UDELAY_COUNT	1000	/* Wait 10ms max. during EC ops */
#define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */

#define ACPI_EC_COMMAND_READ	0x80
#define ACPI_EC_COMMAND_WRITE	0x81
#define ACPI_EC_COMMAND_QUERY	0x84

static int acpi_ec_add (struct acpi_device *device);
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 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,
			},
};

struct acpi_ec {
	acpi_handle			handle;
	unsigned long			uid;
	unsigned long			gpe_bit;
	struct acpi_generic_address	status_addr;
	struct acpi_generic_address	command_addr;
	struct acpi_generic_address	data_addr;
	unsigned long			global_lock;
	spinlock_t			lock;
};

/* If we find an EC via the ECDT, we need to keep a ptr to its context */
static struct acpi_ec	*ec_ecdt;

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

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

static int
acpi_ec_wait (
	struct acpi_ec		*ec,
	u8			event)
{
	u32			acpi_ec_status = 0;
	u32			i = ACPI_EC_UDELAY_COUNT;

	if (!ec)
		return -EINVAL;

	/* Poll the EC status register waiting for the event to occur. */
	switch (event) {
	case ACPI_EC_EVENT_OBF:
		do {
			acpi_hw_low_level_read(8, &acpi_ec_status, &ec->status_addr);
			if (acpi_ec_status & ACPI_EC_FLAG_OBF)
				return 0;
			udelay(ACPI_EC_UDELAY);
		} while (--i>0);
		break;
	case ACPI_EC_EVENT_IBE:
		do {
			acpi_hw_low_level_read(8, &acpi_ec_status, &ec->status_addr);
			if (!(acpi_ec_status & ACPI_EC_FLAG_IBF))
				return 0;
			udelay(ACPI_EC_UDELAY);
		} while (--i>0);
		break;
	default:
		return -EINVAL;
	}

	return -ETIME;
}


static int
acpi_ec_read (
	struct acpi_ec		*ec,
	u8			address,
	u32			*data)
{
	acpi_status		status = AE_OK;
	int			result = 0;
	unsigned long		flags = 0;
	u32			glk = 0;

	ACPI_FUNCTION_TRACE("acpi_ec_read");

	if (!ec || !data)
		return_VALUE(-EINVAL);

	*data = 0;

	if (ec->global_lock) {
		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
		if (ACPI_FAILURE(status))
			return_VALUE(-ENODEV);
	}
	
	spin_lock_irqsave(&ec->lock, flags);

	acpi_hw_low_level_write(8, ACPI_EC_COMMAND_READ, &ec->command_addr);
	result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBE);
	if (result)
		goto end;

	acpi_hw_low_level_write(8, address, &ec->data_addr);
	result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
	if (result)
		goto end;


	acpi_hw_low_level_read(8, data, &ec->data_addr);

	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Read [%02x] from address [%02x]\n",
		*data, address));

end:
	spin_unlock_irqrestore(&ec->lock, flags);

	if (ec->global_lock)
		acpi_release_global_lock(glk);

	return_VALUE(result);
}


static int
acpi_ec_write (
	struct acpi_ec		*ec,
	u8			address,
	u8			data)
{
	int			result = 0;
	acpi_status		status = AE_OK;
	unsigned long		flags = 0;