text: /*
   *  ec.c - ACPI Embedded Controller Driver (v2.1)
   *
   *  Copyright (C) 2006-2008 Alexey Starikovskiy <astarikovskiy@suse.de>
   *  Copyright (C) 2006 Denis Sadykov <denis.m.sadykov@intel.com>
   *  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.
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   */
  
  /* Uncomment next line to get verbose printout */
  /* #define DEBUG */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/types.h>
  #include <linux/delay.h>
  #include <linux/interrupt.h>
  #include <linux/list.h>
  #include <linux/spinlock.h>
  #include <linux/slab.h>
  #include <asm/io.h>
  #include <acpi/acpi_bus.h>
  #include <acpi/acpi_drivers.h>
  #include <linux/dmi.h>
  
  #include "internal.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,
  };
  
  #define ACPI_EC_DELAY		500	/* Wait 500ms max. during EC ops */
  #define ACPI_EC_UDELAY_GLK	1000	/* Wait 1ms max. to get global lock */
  #define ACPI_EC_MSI_UDELAY	550	/* Wait 550us for MSI EC */
  
  enum {
  	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
  	EC_FLAGS_GPE_STORM,		/* GPE storm detected */
  	EC_FLAGS_HANDLERS_INSTALLED,	/* Handlers for GPE and
  					 * OpReg are installed */
  	EC_FLAGS_BLOCKED,		/* Transactions are blocked */
  };
  
  /* ec.c is compiled in acpi namespace so this shows up as acpi.ec_delay param */
  static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
  module_param(ec_delay, uint, 0644);
  MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
  
  /*
   * If the number of false interrupts per one transaction exceeds
   * this threshold, will think there is a GPE storm happened and
   * will disable the GPE for normal transaction.
   */
  static unsigned int ec_storm_threshold  __read_mostly = 8;
  module_param(ec_storm_threshold, uint, 0644);
  MODULE_PARM_DESC(ec_storm_threshold, "Maxim false GPE numbers not considered as GPE storm");
  
  /* 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;
  };
  
  struct transaction {
  	const u8 *wdata;
  	u8 *rdata;
  	unsigned short irq_count;
  	u8 command;
  	u8 wi;
  	u8 ri;
  	u8 wlen;
  	u8 rlen;
  	bool done;
  };
  
  struct acpi_ec *boot_ec, *first_ec;
  EXPORT_SYMBOL(first_ec);
  
  static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
  static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
  static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
  
  /* --------------------------------------------------------------------------
                               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 x;
  }
  
  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 int ec_transaction_done(struct acpi_ec *ec)
  {
  	unsigned long flags;
  	int ret = 0;
  	spin_lock_irqsave(&ec->curr_lock, flags);
  	if (!ec->curr || ec->curr->done)
  		ret = 1;
  	spin_unlock_irqrestore(&ec->curr_lock, flags);
  	return ret;
  }
  
  static void start_transaction(struct acpi_ec *ec)
  {
  	ec->curr->irq_count = ec->curr->wi = ec->curr->ri = 0;
  	ec->curr->done = false;
  	acpi_ec_write_cmd(ec, ec->curr->command);
  }
  
  static void advance_transaction(struct acpi_ec *ec, u8 status)
  {
  	unsigned long flags;
  	spin_lock_irqsave(&ec->curr_lock, flags);
  	if (!ec->curr)
  		goto unlock;
  	if (ec->curr->wlen > ec->curr->wi) {
  		if ((status & ACPI_EC_FLAG_IBF) == 0)
  			acpi_ec_write_data(ec,
  				ec->curr->wdata[ec->curr->wi++]);
  		else
  			goto err;
  	} else if (ec->curr->rlen > ec->curr->ri) {
  		if ((status & ACPI_EC_FLAG_OBF) == 1) {
  			ec->curr->rdata[ec->curr->ri++] = acpi_ec_read_data(ec);
  			if (ec->curr->rlen == ec->curr->ri)
  				ec->curr->done = true;
  		} else
  			goto err;
  	} else if (ec->curr->wlen == ec->curr->wi &&
  		   (status & ACPI_EC_FLAG_IBF) == 0)
  		ec->curr->done = true;
  	goto unlock;
  err:
  	/* false interrupt, state didn't change */
  	if (in_interrupt())
  		++ec->curr->irq_count;
  unlock:
  	spin_unlock_irqrestore(&ec->curr_lock, flags);
  }
  
  static int acpi_ec_sync_query(struct acpi_ec *ec);
  
  static int ec_check_sci_sync(struct acpi_ec *ec, u8 state)
  {
  	if (state & ACPI_EC_FLAG_SCI) {
  		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
  			return acpi_ec_sync_query(ec);
  	}
  	return 0;
  }
  
  static int ec_poll(struct acpi_ec *ec)
  {
  	unsigned long flags;
  	int repeat = 5; /* number of command restarts */
  	while (repeat--) {
  		unsigned long delay = jiffies +
  			msecs_to_jiffies(ec_delay);
  		do {
  			/* don't sleep with disabled interrupts */
  			if (EC_FLAGS_MSI || irqs_disabled()) {
  				udelay(ACPI_EC_MSI_UDELAY);
  				if (ec_transaction_done(ec))
  					return 0;
  			} else {
  				if (wait_event_timeout(ec->wait,
  						ec_transaction_done(ec),
  						msecs_to_jiffies(1)))
  					return 0;
  			}
  			advance_transaction(ec, acpi_ec_read_status(ec));
  		} while (time_before(jiffies, delay));
  		pr_debug(PREFIX "controller reset, restart transaction\n");
  		spin_lock_irqsave(&ec->curr_lock, flags);
  		start_transaction(ec);
  		spin_unlock_irqrestore(&ec->curr_lock, flags);
  	}
  	return -ETIME;
  }
  
  static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
  					struct transaction *t)
  {
  	unsigned long tmp;
  	int ret = 0;
  	if (EC_FLAGS_MSI)
  		udelay(ACPI_EC_MSI_UDELAY);
  	/* start transaction */
  	spin_lock_irqsave(&ec->curr_lock, tmp);
  	/* following two actions should be kept atomic */
  	ec->curr = t;
  	start_transaction(ec);
  	if (ec->curr->command == ACPI_EC_COMMAND_QUERY)
  		clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
  	spin_unlock_irqrestore(&ec->curr_lock, tmp);
  	ret = ec_poll(ec);
  	spin_lock_irqsave(&ec->curr_lock, tmp);
  	ec->curr = NULL;
  	spin_unlock_irqrestore(&ec->curr_lock, tmp);
  	return ret;
  }
  
  static int ec_check_ibf0(struct acpi_ec *ec)
  {
  	u8 status = acpi_ec_read_status(ec);
  	return (status & ACPI_EC_FLAG_IBF) == 0;
  }
  
  static int ec_wait_ibf0(struct acpi_ec *ec)
  {
  	unsigned long delay = jiffies + msecs_to_jiffies(ec_delay);
  	/* interrupt wait manually if GPE mode is not active */
  	while (time_before(jiffies, delay))
  		if (wait_event_timeout(ec->wait, ec_check_ibf0(ec),
  					msecs_to_jiffies(1)))
  			return 0;
  	return -ETIME;
  }
  
  static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
  {
  	int status;
  	u32 glk;
  	if (!ec || (!t) || (t->wlen && !t->wdata) || (t->rlen && !t->rdata))
  		return -EINVAL;
  	if (t->rdata)
  		memset(t->rdata, 0, t->rlen);
  	mutex_lock(&ec->lock);
  	if (test_bit(EC_FLAGS_BLOCKED, &ec->flags)) {
  		status = -EINVAL;
  		goto unlock;
  	}
  	if (ec->global_lock) {
  		status = acpi_acquire_global_lock(ACPI_EC_UDELAY_GLK, &glk);
  		if (ACPI_FAILURE(status)) {
  			status = -ENODEV;
  			goto unlock;
  		}
  	}
  	if (ec_wait_ibf0(ec)) {
  		pr_err(PREFIX "input buffer is not empty, "
  				"aborting transaction\n");
  		status = -ETIME;
  		goto end;
  	}
  	pr_debug(PREFIX "transaction start\n");
  	/* disable GPE during transaction if storm is detected */
  	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
  		/* It has to be disabled, so that it doesn't trigger. */
  		acpi_disable_gpe(NULL, ec->gpe);
  	}
  
  	status = acpi_ec_transaction_unlocked(ec, t);
  
  	/* check if we received SCI during transaction */
  	ec_check_sci_sync(ec, acpi_ec_read_status(ec));
  	if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
  		msleep(1);
  		/* It is safe to enable the GPE outside of the transaction. */
  		acpi_enable_gpe(NULL, ec->gpe);
  	} else if (t->irq_count > ec_storm_threshold) {
  		pr_info(PREFIX "GPE storm detected, "
  			"transactions will use polling mode\n");
  		set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
  	}
  	pr_debug(PREFIX "transaction end\n");
  end:
  	if (ec->global_lock)
  		acpi_release_global_lock(glk);
  unlock:
  	mutex_unlock(&ec->lock);
  	return status;
  }
  
  static int acpi_ec_burst_enable(struct acpi_ec *ec)
  {
  	u8 d;
  	struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
  				.wdata = NULL, .rdata = &d,
  				.wlen = 0, .rlen = 1};
  
  	return acpi_ec_transaction(ec, &t);
  }
  
  static int acpi_ec_burst_disable(struct acpi_ec *ec)
  {
  	struct transaction t = {.command = ACPI_EC_BURST_DISABLE,
  				.wdata = NULL, .rdata = NULL,
  				.wlen = 0, .rlen = 0};
  
  	return (acpi_ec_read_status(ec) & ACPI_EC_FLAG_BURST) ?
  				acpi_ec_transaction(ec, &t) : 0;
  }
  
  static int acpi_ec_read(struct acpi_ec *ec, u8 address, u8 * data)
  {
  	int result;
  	u8 d;
  	struct transaction t = {.command = ACPI_EC_COMMAND_READ,
  				.wdata = &address, .rdata = &d,
  				.wlen = 1, .rlen = 1};
  
  	result = acpi_ec_transaction(ec, &t);
  	*data = d;
  	return result;
  }
  
  static int acpi_ec_write(struct acpi_ec *ec, u8 address, u8 data)
  {
  	u8 wdata[2] = { address, data };
  	struct transaction t = {.command = ACPI_EC_COMMAND_WRITE,
  				.wdata = wdata, .rdata = NULL,
  				.wlen = 2, .rlen = 0};
  
  	return acpi_ec_transaction(ec, &t);
  }
  
  /*
   * 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)
  {
  	struct transaction t = {.command = command,
  				.wdata = wdata, .rdata = rdata,
  				.wlen = wdata_len, .rlen = rdata_len};
  	if (!first_ec)
  		return -ENODEV;
  
  	return acpi_ec_transaction(first_ec, &t);
  }
  
  EXPORT_SYMBOL(ec_transaction);
  
  /* Get the handle to the EC device */
  acpi_handle ec_get_handle(void)
  {
  	if (!first_ec)
  		return NULL;
  	return first_ec->handle;
  }
  
  EXPORT_SYMBOL(ec_get_handle);
  
  void acpi_ec_block_transactions(void)
  {
  	struct acpi_ec *ec = first_ec;
  
  	if (!ec)
  		return;
  
  	mutex_lock(&ec->lock);
  	/* Prevent transactions from being carried out */
  	set_bit(EC_FLAGS_BLOCKED, &ec->flags);
  	mutex_unlock(&ec->lock);
  }
  
  void acpi_ec_unblock_transactions(void)
  {
  	struct acpi_ec *ec = first_ec;
  
  	if (!ec)
  		return;
  
  	mutex_lock(&ec->lock);
  	/* Allow transactions to be carried out again */
  	clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
  	mutex_unlock(&ec->lock);
  }
  
  void acpi_ec_unblock_transactions_early(void)
  {
  	/*
  	 * Allow transactions to happen again (this function is called from
  	 * atomic context during wakeup, so we don't need to acquire the mutex).
  	 */
  	if (first_ec)
  		clear_bit(EC_FLAGS_BLOCKED, &first_ec->flags);
  }
  
  static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 * data)
  {
  	int result;
  	u8 d;
  	struct transaction t = {.command = ACPI_EC_COMMAND_QUERY,
  				.wdata = NULL, .rdata = &d,
  				.wlen = 0, .rlen = 1};
  	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_unlocked(ec, &t);
  	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);
  
  static void acpi_ec_run(void *cxt)
  {
  	struct acpi_ec_query_handler *handler = cxt;
  	if (!handler)
  		return;
  	pr_debug(PREFIX "start query execution\n");
  	if (handler->func)
  		handler->func(handler->data);
  	else if (handler->handle)
  		acpi_evaluate_object(handler->handle, NULL, NULL, NULL);
  	pr_debug(PREFIX "stop query execution\n");
  	kfree(handler);
  }
  
  static int acpi_ec_sync_query(struct acpi_ec *ec)
  {
  	u8 value = 0;
  	int status;
  	struct acpi_ec_query_handler *handler, *copy;
  	if ((status = acpi_ec_query_unlocked(ec, &value)))
  		return status;
  	list_for_each_entry(handler, &ec->list, node) {
  		if (value == handler->query_bit) {
  			/* have custom handler for this bit */
  			copy = kmalloc(sizeof(*handler), GFP_KERNEL);
  			if (!copy)
  				return -ENOMEM;
  			memcpy(copy, handler, sizeof(*copy));
  			pr_debug(PREFIX "push query execution (0x%2x) on queue\n", value);
  			return acpi_os_execute((copy->func) ?
  				OSL_NOTIFY_HANDLER : OSL_GPE_HANDLER,
  				acpi_ec_run, copy);
  		}
  	}
  	return 0;
  }
  
  static void acpi_ec_gpe_query(void *ec_cxt)
  {
  	struct acpi_ec *ec = ec_cxt;
  	if (!ec)
  		return;
  	mutex_lock(&ec->lock);
  	acpi_ec_sync_query(ec);
  	mutex_unlock(&ec->lock);
  }
  
  static int ec_check_sci(struct acpi_ec *ec, u8 state)
  {
  	if (state & ACPI_EC_FLAG_SCI) {
  		if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags)) {
  			pr_debug(PREFIX "push gpe query to the queue\n");
  			return acpi_os_execute(OSL_NOTIFY_HANDLER,
  				acpi_ec_gpe_query, ec);
  		}
  	}
  	return 0;
  }
  
  static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
  	u32 gpe_number, void *data)
  {
  	struct acpi_ec *ec = data;
  
  	pr_debug(PREFIX "~~~> interrupt\n");
  
  	advance_transaction(ec, acpi_ec_read_status(ec));
  	if (ec_transaction_done(ec) &&
  	    (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
  		wake_up(&ec->wait);
  		ec_check_sci(ec, acpi_ec_read_status(ec));
  	}
  	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
  }
  
  /* --------------------------------------------------------------------------
                               Address Space Management
     -------------------------------------------------------------------------- */
  
  static acpi_status
  acpi_ec_space_handler(u32 function, acpi_physical_address address,
  		      u32 bits, u64 *value64,
  		      void *handler_context, void *region_context)
  {
  	struct acpi_ec *ec = handler_context;
  	int result = 0, i, bytes = bits / 8;
  	u8 *value = (u8 *)value64;
  
  	if ((address > 0xFF) || !value || !handler_context)
  		return AE_BAD_PARAMETER;
  
  	if (function != ACPI_READ && function != ACPI_WRITE)
  		return AE_BAD_PARAMETER;
  
  	if (EC_FLAGS_MSI || bits > 8)
  		acpi_ec_burst_enable(ec);
  
  	for (i = 0; i < bytes; ++i, ++address, ++value)
  		result = (function == ACPI_READ) ?
  			acpi_ec_read(ec, address, value) :
  			acpi_ec_write(ec, address, *value);
  
  	if (EC_FLAGS_MSI || bits > 8)
  		acpi_ec_burst_disable(ec);
  
  	switch (result) {
  	case -EINVAL:
  		return AE_BAD_PARAMETER;
  		break;
  	case -ENODEV:
  		return AE_NOT_FOUND;
  		break;
  	case -ETIME:
  		return AE_TIME;
  		break;
  	default:
  		return AE_OK;
  	}
  }
  
  /* --------------------------------------------------------------------------
                                 Driver Interface
     -------------------------------------------------------------------------- */
  static acpi_status
  ec_parse_io_ports(struct acpi_resource *resource, void *context);
  
  static struct acpi_ec *make_acpi_ec(void)
  {
  	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
  	if (!ec)
  		return NULL;
  	ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
  	mutex_init(&ec->lock);
  	init_waitqueue_head(&ec->wait);
  	INIT_LIST_HEAD(&ec->list);
  	spin_lock_init(&ec->curr_lock);
  	return ec;
  }
  
  static acpi_status
  acpi_ec_register_query_methods(acpi_handle handle, u32 level,
  			       void *context, void **return_value)
  {
  	char node_name[5];
  	struct acpi_buffer buffer = { sizeof(node_name), node_name };
  	struct acpi_ec *ec = context;
  	int value = 0;
  	acpi_status status;
  
  	status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
  
  	if (ACPI_SUCCESS(status) && sscanf(node_name, "_Q%x", &value) == 1) {
  		acpi_ec_add_query_handler(ec, value, handle, NULL, NULL);
  	}
  	return AE_OK;
  }
  
  static acpi_status
  ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
  {
  	acpi_status status;
  	unsigned long long tmp = 0;
  
  	struct acpi_ec *ec = context;
  
  	/* clear addr values, ec_parse_io_ports depend on it */
  	ec->command_addr = ec->data_addr = 0;
  
  	status = acpi_walk_resources(handle, METHOD_NAME__CRS,
  				     ec_parse_io_ports, ec);
  	if (ACPI_FAILURE(status))
  		return status;
  
  	/* Get GPE bit assignment (EC events). */
  	/* TODO: Add support for _GPE returning a package */
  	status = acpi_evaluate_integer(handle, "_GPE", NULL, &tmp);
  	if (ACPI_FAILURE(status))
  		return status;
  	ec->gpe = tmp;
  	/* Use the global lock for all EC transactions? */
  	tmp = 0;
  	acpi_evaluate_integer(handle, "_GLK", NULL, &tmp);
  	ec->global_lock = tmp;
  	ec->handle = handle;
  	return AE_CTRL_TERMINATE;
  }
  
  static int ec_install_handlers(struct acpi_ec *ec)
  {
  	acpi_status status;
  	if (test_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags))
  		return 0;
  	status = acpi_install_gpe_handler(NULL, ec->gpe,
  				  ACPI_GPE_EDGE_TRIGGERED,
  				  &acpi_ec_gpe_handler, ec);
  	if (ACPI_FAILURE(status))
  		return -ENODEV;
  
  	acpi_enable_gpe(NULL, ec->gpe);
  	status = acpi_install_address_space_handler(ec->handle,
  						    ACPI_ADR_SPACE_EC,
  						    &acpi_ec_space_handler,
  						    NULL, ec);
  	if (ACPI_FAILURE(status)) {
  		if (status == AE_NOT_FOUND) {
  			/*
  			 * Maybe OS fails in evaluating the _REG object.
  			 * The AE_NOT_FOUND error will be ignored and OS
  			 * continue to initialize EC.
  			 */
  			printk(KERN_ERR "Fail in evaluating the _REG object"
  				" of EC device. Broken bios is suspected.\n");
  		} else {
  			acpi_remove_gpe_handler(NULL, ec->gpe,
  				&acpi_ec_gpe_handler);
  			acpi_disable_gpe(NULL, ec->gpe);
  			return -ENODEV;
  		}
  	}
  
  	set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
  	return 0;
  }
  
  static void ec_remove_handlers(struct acpi_ec *ec)
  {
  	acpi_disable_gpe(NULL, ec->gpe);
  	if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
  				ACPI_ADR_SPACE_EC, &acpi_ec_space_handler)))
  		pr_err(PREFIX "failed to remove space handler\n");
  	if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
  				&acpi_ec_gpe_handler)))
  		pr_err(PREFIX "failed to remove gpe handler\n");
  	clear_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
  }
  
  static int acpi_ec_add(struct acpi_device *device)
  {
  	struct acpi_ec *ec = NULL;
  	int ret;
  
  	strcpy(acpi_device_name(device), ACPI_EC_DEVICE_NAME);
  	strcpy(acpi_device_class(device), ACPI_EC_CLASS);
  
  	/* Check for boot EC */
  	if (boot_ec &&
  	    (boot_ec->handle == device->handle ||
  	     boot_ec->handle == ACPI_ROOT_OBJECT)) {
  		ec = boot_ec;
  		boot_ec = NULL;
  	} else {
  		ec = make_acpi_ec();
  		if (!ec)
  			return -ENOMEM;
  	}
  	if (ec_parse_device(device->handle, 0, ec, NULL) !=
  		AE_CTRL_TERMINATE) {
  			kfree(ec);
  			return -EINVAL;
  	}
  
  	/* Find and register all query methods */
  	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
  			    acpi_ec_register_query_methods, NULL, ec, NULL);
  
  	if (!first_ec)
  		first_ec = ec;
  	device->driver_data = ec;
  
  	ret = !!request_region(ec->data_addr, 1, "EC data");
  	WARN(!ret, "Could not request EC data io port 0x%lx", ec->data_addr);
  	ret = !!request_region(ec->command_addr, 1, "EC cmd");
  	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
  
  	pr_info(PREFIX "GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
  			  ec->gpe, ec->command_addr, ec->data_addr);
  
  	ret = ec_install_handlers(ec);
  
  	/* EC is fully operational, allow queries */
  	clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
  	return ret;
  }
  
  static int acpi_ec_remove(struct acpi_device *device, int type)
  {
  	struct acpi_ec *ec;
  	struct acpi_ec_query_handler *handler, *tmp;
  
  	if (!device)
  		return -EINVAL;
  
  	ec = acpi_driver_data(device);
  	ec_remove_handlers(ec);
  	mutex_lock(&ec->lock);
  	list_for_each_entry_safe(handler, tmp, &ec->list, node) {
  		list_del(&handler->node);
  		kfree(handler);
  	}
  	mutex_unlock(&ec->lock);
  	release_region(ec->data_addr, 1);
  	release_region(ec->command_addr, 1);
  	device->driver_data = NULL;
  	if (ec == first_ec)
  		first_ec = NULL;
  	kfree(ec);
  	return 0;
  }
  
  static acpi_status
  ec_parse_io_ports(struct acpi_resource *resource, void *context)
  {
  	struct acpi_ec *ec = context;
  
  	if (resource->type != ACPI_RESOURCE_TYPE_IO)
  		return AE_OK;
  
  	/*
  	 * The first address region returned is the data port, and
  	 * the second address region returned is the status/command
  	 * port.
  	 */
  	if (ec->data_addr == 0)
  		ec->data_addr = resource->data.io.minimum;
  	else if (ec->command_addr == 0)
  		ec->command_addr = resource->data.io.minimum;
  	else
  		return AE_CTRL_TERMINATE;
  
  	return AE_OK;
  }
  
  int __init acpi_boot_ec_enable(void)
  {
  	if (!boot_ec || test_bit(EC_FLAGS_HANDLERS_INSTALLED, &boot_ec->flags))
  		return 0;
  	if (!ec_install_handlers(boot_ec)) {
  		first_ec = boot_ec;
  		return 0;
  	}
  	return -EFAULT;
  }
  
  static const struct acpi_device_id ec_device_ids[] = {
  	{"PNP0C09", 0},
  	{"", 0},
  };
  
  /* Some BIOS do not survive early DSDT scan, skip it */
  static int ec_skip_dsdt_scan(const struct dmi_system_id *id)
  {
  	EC_FLAGS_SKIP_DSDT_SCAN = 1;
  	return 0;
  }
  
  /* ASUStek often supplies us with broken ECDT, validate it */
  static int ec_validate_ecdt(const struct dmi_system_id *id)
  {
  	EC_FLAGS_VALIDATE_ECDT = 1;
  	return 0;
  }
  
  /* MSI EC needs special treatment, enable it */
  static int ec_flag_msi(const struct dmi_system_id *id)
  {
  	printk(KERN_DEBUG PREFIX "Detected MSI hardware, enabling workarounds.\n");
  	EC_FLAGS_MSI = 1;
  	EC_FLAGS_VALIDATE_ECDT = 1;
  	return 0;
  }
  
  /*
   * Clevo M720 notebook actually works ok with IRQ mode, if we lifted
   * the GPE storm threshold back to 20
   */
  static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
  {
  	pr_debug("Setting the EC GPE storm threshold to 20\n");
  	ec_storm_threshold  = 20;
  	return 0;
  }
  
  static struct dmi_system_id __initdata ec_dmi_table[] = {
  	{
  	ec_skip_dsdt_scan, "Compal JFL92", {
  	DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
  	DMI_MATCH(DMI_BOARD_NAME, "JFL92") }, NULL},
  	{
  	ec_flag_msi, "MSI hardware", {
  	DMI_MATCH(DMI_BIOS_VENDOR, "Micro-Star")}, NULL},
  	{
  	ec_flag_msi, "MSI hardware", {
  	DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star")}, NULL},
  	{
  	ec_flag_msi, "MSI hardware", {
  	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-Star")}, NULL},
  	{
  	ec_flag_msi, "MSI hardware", {
  	DMI_MATCH(DMI_CHASSIS_VENDOR, "MICRO-STAR")}, NULL},
  	{
  	ec_flag_msi, "Quanta hardware", {
  	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
  	DMI_MATCH(DMI_PRODUCT_NAME, "TW8/SW8/DW8"),}, NULL},
  	{
  	ec_flag_msi, "Quanta hardware", {
  	DMI_MATCH(DMI_SYS_VENDOR, "Quanta"),
  	DMI_MATCH(DMI_PRODUCT_NAME, "TW9/SW9"),}, NULL},
  	{
  	ec_validate_ecdt, "ASUS hardware", {
  	DMI_MATCH(DMI_BIOS_VENDOR, "ASUS") }, NULL},
  	{
  	ec_validate_ecdt, "ASUS hardware", {
  	DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer Inc.") }, NULL},
  	{
  	ec_enlarge_storm_threshold, "CLEVO hardware", {
  	DMI_MATCH(DMI_SYS_VENDOR, "CLEVO Co."),
  	DMI_MATCH(DMI_PRODUCT_NAME, "M720T/M730T"),}, NULL},
  	{
  	ec_skip_dsdt_scan, "HP Folio 13", {
  	DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
  	DMI_MATCH(DMI_PRODUCT_NAME, "HP Folio 13"),}, NULL},
  	{
  	ec_validate_ecdt, "ASUS hardware", {
  	DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
  	DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
  	{},
  };
  
  int __init acpi_ec_ecdt_probe(void)
  {
  	acpi_status status;
  	struct acpi_ec *saved_ec = NULL;
  	struct acpi_table_ecdt *ecdt_ptr;
  
  	boot_ec = make_acpi_ec();
  	if (!boot_ec)
  		return -ENOMEM;
  	/*
  	 * Generate a boot ec context
  	 */
  	dmi_check_system(ec_dmi_table);
  	status = acpi_get_table(ACPI_SIG_ECDT, 1,
  				(struct acpi_table_header **)&ecdt_ptr);
  	if (ACPI_SUCCESS(status)) {
  		pr_info(PREFIX "EC description table is found, configuring boot EC\n");
  		boot_ec->command_addr = ecdt_ptr->control.address;
  		boot_ec->data_addr = ecdt_ptr->data.address;
  		boot_ec->gpe = ecdt_ptr->gpe;
  		boot_ec->handle = ACPI_ROOT_OBJECT;
  		acpi_get_handle(ACPI_ROOT_OBJECT, ecdt_ptr->id, &boot_ec->handle);
  		/* Don't trust ECDT, which comes from ASUSTek */
  		if (!EC_FLAGS_VALIDATE_ECDT)
  			goto install;
  		saved_ec = kmemdup(boot_ec, sizeof(struct acpi_ec), GFP_KERNEL);
  		if (!saved_ec)
  			return -ENOMEM;
  	/* fall through */
  	}
  
  	if (EC_FLAGS_SKIP_DSDT_SCAN)
  		return -ENODEV;
  
  	/* This workaround is needed only on some broken machines,
  	 * which require early EC, but fail to provide ECDT */
  	printk(KERN_DEBUG PREFIX "Look up EC in DSDT\n");
  	status = acpi_get_devices(ec_device_ids[0].id, ec_parse_device,
  					boot_ec, NULL);
  	/* Check that acpi_get_devices actually find something */
  	if (ACPI_FAILURE(status) || !boot_ec->handle)
  		goto error;
  	if (saved_ec) {
  		/* try to find good ECDT from ASUSTek */
  		if (saved_ec->command_addr != boot_ec->command_addr ||
  		    saved_ec->data_addr != boot_ec->data_addr ||
  		    saved_ec->gpe != boot_ec->gpe ||
  		    saved_ec->handle != boot_ec->handle)
  			pr_info(PREFIX "ASUSTek keeps feeding us with broken "
  			"ECDT tables, which are very hard to workaround. "
  			"Trying to use DSDT EC info instead. Please send "
  			"output of acpidump to linux-acpi@vger.kernel.org\n");
  		kfree(saved_ec);
  		saved_ec = NULL;
  	} else {
  		/* We really need to limit this workaround, the only ASUS,
  		* which needs it, has fake EC._INI method, so use it as flag.
  		* Keep boot_ec struct as it will be needed soon.
  		*/
  		acpi_handle dummy;
  		if (!dmi_name_in_vendors("ASUS") ||
  		    ACPI_FAILURE(acpi_get_handle(boot_ec->handle, "_INI",
  							&dummy)))
  			return -ENODEV;
  	}
  install:
  	if (!ec_install_handlers(boot_ec)) {
  		first_ec = boot_ec;
  		return 0;
  	}
  error:
  	kfree(boot_ec);
  	boot_ec = NULL;
  	return -ENODEV;
  }
  
  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,
  		},
  };
  
  int __init acpi_ec_init(void)
  {
  	int result = 0;
  
  	/* Now register the driver for the EC */
  	result = acpi_bus_register_driver(&acpi_ec_driver);
  	if (result < 0)
  		return -ENODEV;
  
  	return result;
  }
  
  /* EC driver currently not unloadable */
  #if 0
  static void __exit acpi_ec_exit(void)
  {
  
  	acpi_bus_unregister_driver(&acpi_ec_driver);
  	return;
  }
  #endif	/* 0 */
  