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"


#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 */

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

#define ACPI_EC_DELAY		50	/* Wait 50ms 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_BURST_ENABLE	0x82
#define ACPI_EC_BURST_DISABLE	0x83
#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;
	unsigned int			expect_event;
	atomic_t			leaving_burst; /* 0 : No, 1 : Yes, 2: abort*/
	atomic_t			pending_gpe;
	struct semaphore		sem;
	wait_queue_head_t		wait;
};

/* 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 inline u32 acpi_ec_read_status(struct acpi_ec *ec)
{
	u32	status = 0;

	acpi_hw_low_level_read(8, &status, &ec->status_addr);
	return status;
}

static int acpi_ec_wait(struct acpi_ec *ec, unsigned int event)
{
	int	result = 0;

	ACPI_FUNCTION_TRACE("acpi_ec_wait");

	ec->expect_event = event;
	smp_mb();

	result = wait_event_interruptible_timeout(ec->wait,
					!ec->expect_event,
					msecs_to_jiffies(ACPI_EC_DELAY));
	
	ec->expect_event = 0;
	smp_mb();

	if (result < 0){
		ACPI_DEBUG_PRINT((ACPI_DB_ERROR," result  = %d ", result));
		return_VALUE(result);
	}

	/*
	 * Verify that the event in question has actually happened by
	 * querying EC status. Do the check even if operation timed-out
	 * to make sure that we did not miss interrupt.
	 */
	switch (event) {
	case ACPI_EC_EVENT_OBF:
		if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)
			return_VALUE(0);
		break;

	case ACPI_EC_EVENT_IBE:
		if (~acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)
			return_VALUE(0);
		break;
	}

	return_VALUE(-ETIME);
}



static int
acpi_ec_enter_burst_mode (
	struct acpi_ec		*ec)
{
	u32			tmp = 0;
	int			status = 0;

	ACPI_FUNCTION_TRACE("acpi_ec_enter_burst_mode");

	status = acpi_ec_read_status(ec);
	if (status != -EINVAL &&
		!(status & ACPI_EC_FLAG_BURST)){
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,"entering burst mode \n"));
		acpi_hw_low_level_write(8, ACPI_EC_BURST_ENABLE, &ec->command_addr);
		status = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF);
		if (status){
			acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
			ACPI_DEBUG_PRINT((ACPI_DB_ERROR," status = %d\n", status));
			return_VALUE(-EINVAL);
		}
		acpi_hw_low_level_read(8, &tmp, &ec->data_addr);
		acpi_enable_gpe(NULL, ec->gpe_bit, ACPI_NOT_ISR);
		if(tmp != 0x90 ) {/* Burst ACK byte*/
			ACPI_DEBUG_PRINT((ACPI_DB_ERROR,"Ack failed \n"));
			return_VALUE(-EINVAL);
		}
	} else
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,"already be in burst mode \n"));
	atomic_set(&ec->leaving_burst , 0);
	return_VALUE(0);
}

static int
acpi_ec_leave_burst_mode (
	struct acpi_ec		*ec)
{
	int			status =0;

	ACPI_FUNCTION_TRACE("acpi_ec_leave_burst_mode");