ec.c

linux 内核源代码

/*
 *  ec.c - ACPI Embedded Controller Driver (v2.0)
 *
 *  Copyright (C) 2006, 2007 Alexey Starikovskiy <[e-mail]>
 *  Copyright (C) 2006 Denis Sadykov <[e-mail]>
 *  Copyright (C) 2004 Luming Yu <[e-mail]>
 *  Copyright (C) 2001, 2002 Andy Grover <[e-mail]>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[e-mail]>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

/* Uncomment next line to get verbose print outs*/
/* #define DEBUG */

#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 <linux/list.h>
#include <asm/io.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <acpi/actypes.h>

#define ACPI_EC_CLASS			"embedded_controller"
#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 */
enum ec_command {
	ACPI_EC_COMMAND_READ = 0x80,
	ACPI_EC_COMMAND_WRITE = 0x81,
	ACPI_EC_BURST_ENABLE = 0x82,
	ACPI_EC_BURST_DISABLE = 0x83,
	ACPI_EC_COMMAND_QUERY = 0x84,
};

/* EC events */
enum ec_event {
	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_FLAGS_WAIT_GPE = 0,		/* Don't check status until GPE arrives */
	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
	EC_FLAGS_GPE_MODE,		/* Expect GPE to be sent for status change */
	EC_FLAGS_NO_ADDRESS_GPE,	/* Expect GPE only for non-address event */
	EC_FLAGS_ADDRESS,		/* Address is being written */
	EC_FLAGS_NO_WDATA_GPE,		/* Don't expect WDATA GPE event */
	EC_FLAGS_WDATA,			/* Data is being written */
	EC_FLAGS_NO_OBF1_GPE,		/* Don't expect GPE before read */
};

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 const struct acpi_device_id ec_device_ids[] = {
	{"PNP0C09", 0},
	{"", 0},
};

static struct acpi_driver acpi_ec_driver = {
	.name = "ec",
	.class = ACPI_EC_CLASS,
	.ids = ec_device_ids,
	.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 */
/* External interfaces use first EC only, so remember */
typedef int (*acpi_ec_query_func) (void *data);

struct acpi_ec_query_handler {
	struct list_head node;
	acpi_ec_query_func func;
	acpi_handle handle;
	void *data;
	u8 query_bit;
};

static struct acpi_ec {
	acpi_handle handle;
	unsigned long gpe;
	unsigned long command_addr;
	unsigned long data_addr;
	unsigned long global_lock;
	unsigned long flags;
	struct mutex lock;
	wait_queue_head_t wait;
	struct list_head list;
	u8 handlers_installed;
} *boot_ec, *first_ec;

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

static inline u8 acpi_ec_read_status(struct acpi_ec *ec)
{
	u8 x = inb(ec->command_addr);
	pr_debug(PREFIX "---> status = 0x%2.2x\n", x);
	return x;
}

static inline u8 acpi_ec_read_data(struct acpi_ec *ec)
{
	u8 x = inb(ec->data_addr);
	pr_debug(PREFIX "---> data = 0x%2.2x\n", x);
	return inb(ec->data_addr);
}

static inline void acpi_ec_write_cmd(struct acpi_ec *ec, u8 command)
{
	pr_debug(PREFIX "<--- command = 0x%2.2x\n", command);
	outb(command, ec->command_addr);
}

static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
{
	pr_debug(PREFIX "<--- data = 0x%2.2x\n", data);
	outb(data, ec->data_addr);
}

static inline int acpi_ec_check_status(struct acpi_ec *ec, enum ec_event event)
{
	if (test_bit(EC_FLAGS_WAIT_GPE, &ec->flags))
		return 0;
	if (event == ACPI_EC_EVENT_OBF_1) {
		if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)
			return 1;
	} else if (event == ACPI_EC_EVENT_IBF_0) {
		if (!(acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF))
			return 1;
	}

	return 0;
}

static int acpi_ec_wait(struct acpi_ec *ec, enum ec_event event, int force_poll)
{
	int ret = 0;

	if (unlikely(event == ACPI_EC_EVENT_OBF_1 &&
		     test_bit(EC_FLAGS_NO_OBF1_GPE, &ec->flags)))
		force_poll = 1;
	if (unlikely(test_bit(EC_FLAGS_ADDRESS, &ec->flags) &&
		     test_bit(EC_FLAGS_NO_ADDRESS_GPE, &ec->flags)))
		force_poll = 1;
	if (unlikely(test_bit(EC_FLAGS_WDATA, &ec->flags) &&
		     test_bit(EC_FLAGS_NO_WDATA_GPE, &ec->flags)))
		force_poll = 1;
	if (likely(test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) &&
	    likely(!force_poll)) {
		if (wait_event_timeout(ec->wait, acpi_ec_check_status(ec, event),
				       msecs_to_jiffies(ACPI_EC_DELAY)))
			goto end;
		clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
		if (acpi_ec_check_status(ec, event)) {
			if (event == ACPI_EC_EVENT_OBF_1) {
				/* miss OBF_1 GPE, don't expect it */
				pr_info(PREFIX "missing OBF confirmation, "
					"don't expect it any longer.\n");
				set_bit(EC_FLAGS_NO_OBF1_GPE, &ec->flags);
			} else if (test_bit(EC_FLAGS_ADDRESS, &ec->flags)) {
				/* miss address GPE, don't expect it anymore */
				pr_info(PREFIX "missing address confirmation, "
					"don't expect it any longer.\n");
				set_bit(EC_FLAGS_NO_ADDRESS_GPE, &ec->flags);
			} else if (test_bit(EC_FLAGS_WDATA, &ec->flags)) {
				/* miss write data GPE, don't expect it */
				pr_info(PREFIX "missing write data confirmation, "
					"don't expect it any longer.\n");
				set_bit(EC_FLAGS_NO_WDATA_GPE, &ec->flags);
			} else {
				/* missing GPEs, switch back to poll mode */
				if (printk_ratelimit())
					pr_info(PREFIX "missing confirmations, "
						"switch off interrupt mode.\n");
				clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
			}
			goto end;
		}
	} else {
		unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
		clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
		while (time_before(jiffies, delay)) {
			if (acpi_ec_check_status(ec, event))
				goto end;
		}
	}
	pr_err(PREFIX "acpi_ec_wait timeout,"
			       " status = %d, expect_event = %d\n",
			       acpi_ec_read_status(ec), event);
	ret = -ETIME;
      end:
	clear_bit(EC_FLAGS_ADDRESS, &ec->flags);
	return ret;
}

static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command,
					const u8 * wdata, unsigned wdata_len,
					u8 * rdata, unsigned rdata_len,
					int force_poll)
{
	int result = 0;
	set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
	acpi_ec_write_cmd(ec, command);
	pr_debug(PREFIX "transaction start\n");
	for (; wdata_len > 0; --wdata_len) {
		result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);
		if (result) {
			pr_err(PREFIX
			       "write_cmd timeout, command = %d\n", command);
			goto end;
		}
		/* mark the address byte written to EC */
		if (rdata_len + wdata_len > 1)
			set_bit(EC_FLAGS_ADDRESS, &ec->flags);
		set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
		acpi_ec_write_data(ec, *(wdata++));
	}

	if (!rdata_len) {
		set_bit(EC_FLAGS_WDATA, &ec->flags);
		result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);
		if (result) {
			pr_err(PREFIX
			       "finish-write timeout, command = %d\n", command);
			goto end;
		}
	} else if (command == ACPI_EC_COMMAND_QUERY)
		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);

	for (; rdata_len > 0; --rdata_len) {
		result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1, force_poll);
		if (result) {
			pr_err(PREFIX "read timeout, command = %d\n", command);
			goto end;
		}
		/* Don't expect GPE after last read */
		if (rdata_len > 1)
			set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
		*(rdata++) = acpi_ec_read_data(ec);
	}
      end:
	pr_debug(PREFIX "transaction end\n");
	return result;
}

static int acpi_ec_transaction(struct acpi_ec *ec, u8 command,
			       const u8 * wdata, unsigned wdata_len,
			       u8 * rdata, unsigned rdata_len,
			       int force_poll)
{
	int status;
	u32 glk;

	if (!ec || (wdata_len && !wdata) || (rdata_len && !rdata))
		return -EINVAL;

	if (rdata)
		memset(rdata, 0, rdata_len);

	mutex_lock(&ec->lock);
	if (ec->global_lock) {
		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
		if (ACPI_FAILURE(status)) {
			mutex_unlock(&ec->lock);
			return -ENODEV;
		}
	}

	status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, 0);
	if (status) {
		pr_err(PREFIX "input buffer is not empty, "
				"aborting transaction\n");
		goto end;
	}

	status = acpi_ec_transaction_unlocked(ec, command,
					      wdata, wdata_len,
					      rdata, rdata_len,
					      force_poll);

      end:

	if (ec->global_lock)
		acpi_release_global_lock(glk);
	mutex_unlock(&ec->lock);

	return status;
}

/*
 * Note: samsung nv5000 doesn't work with ec burst mode.
 * http://bugzilla.kernel.org/show_bug.cgi?id=4980
 */
int acpi_ec_burst_enable(struct acpi_ec *ec)
{
	u8 d;
	return acpi_ec_transaction(ec, ACPI_EC_BURST_ENABLE, NULL, 0, &d, 1, 0);
}

int acpi_ec_burst_disable(struct acpi_ec *ec)
{
	return acpi_ec_transaction(ec, ACPI_EC_BURST_DISABLE, NULL, 0, NULL, 0, 0);
}

static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
{
	int result;
	u8 d;

	result = acpi_ec_transaction(ec, ACPI_EC_COMMAND_READ,
				     &address, 1, &d, 1, 0);
	*data = d;
	return result;
}

static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
{
	u8 wdata[2] = { address, data };
	return acpi_ec_transaction(ec, ACPI_EC_COMMAND_WRITE,
				   wdata, 2, NULL, 0, 0);
}

/*
 * Externally callable EC access functions. For now, assume 1 EC only
 */
int ec_burst_enable(void)
{
	if (!first_ec)
		return -ENODEV;
	return acpi_ec_burst_enable(first_ec);
}

EXPORT_SYMBOL(ec_burst_enable);

int ec_burst_disable(void)
{
	if (!first_ec)
		return -ENODEV;
	return acpi_ec_burst_disable(first_ec);
}

EXPORT_SYMBOL(ec_burst_disable);

int ec_read(u8 addr, u8 * val)
{
	int err;
	u8 temp_data;

	if (!first_ec)
		return -ENODEV;

	err = acpi_ec_read(first_ec, addr, &temp_data);

	if (!err) {
		*val = temp_data;
		return 0;
	} else
		return err;
}

EXPORT_SYMBOL(ec_read);

int ec_write(u8 addr, u8 val)
{
	int err;

	if (!first_ec)
		return -ENODEV;

	err = acpi_ec_write(first_ec, addr, val);

	return err;
}

EXPORT_SYMBOL(ec_write);

int ec_transaction(u8 command,
		   const u8 * wdata, unsigned wdata_len,
		   u8 * rdata, unsigned rdata_len,
		   int force_poll)
{
	if (!first_ec)
		return -ENODEV;

	return acpi_ec_transaction(first_ec, command, wdata,
				   wdata_len, rdata, rdata_len,
				   force_poll);
}

EXPORT_SYMBOL(ec_transaction);

static int acpi_ec_query(struct acpi_ec *ec, u8 * data)
{
	int result;
	u8 d;

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

	/*
	 * Query the EC to find out which _Qxx method we need to evaluate.
	 * Note that successful completion of the query causes the ACPI_EC_SCI
	 * bit to be cleared (and thus clearing the interrupt source).
	 */

	result = acpi_ec_transaction(ec, ACPI_EC_COMMAND_QUERY, NULL, 0, &d, 1, 0);
	if (result)
		return result;

	if (!d)
		return -ENODATA;

	*data = d;
	return 0;
}

/* --------------------------------------------------------------------------
                                Event Management
   -------------------------------------------------------------------------- */
int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
			      acpi_handle handle, acpi_ec_query_func func,
			      void *data)
{
	struct acpi_ec_query_handler *handler =
	    kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL);
	if (!handler)
		return -ENOMEM;

	handler->query_bit = query_bit;
	handler->handle = handle;
	handler->func = func;
	handler->data = data;
	mutex_lock(&ec->lock);
	list_add(&handler->node, &ec->list);
	mutex_unlock(&ec->lock);
	return 0;
}

EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler);

void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit)
{
	struct acpi_ec_query_handler *handler, *tmp;
	mutex_lock(&ec->lock);
	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
		if (query_bit == handler->query_bit) {
			list_del(&handler->node);
			kfree(handler);
		}
	}
	mutex_unlock(&ec->lock);
}

EXPORT_SYMBOL_GPL(acpi_ec_remove_query_handler);