ec.c

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/*
 *  ec.c - ACPI Embedded Controller Driver (v2.1)
 *
 *  Copyright (C) 2006-2008 Alexey Starikovskiy <[email protected]>
 *  Copyright (C) 2006 Denis Sadykov <[email protected]>
 *  Copyright (C) 2004 Luming Yu <[email protected]>
 *  Copyright (C) 2001, 2002 Andy Grover <[email protected]>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <[email protected]>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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 = 2; /* 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));
        if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF)
            break;
        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},
    {},
};

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 [email protected]\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 */