Merge branch 'for_rmk' of git://git.mnementh.co.uk/linux-2.6-im into devel

[mirror_ubuntu-zesty-kernel.git] / drivers / acpi / ec.c

/*
 *  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/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/spinlock.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,
};

#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_UDELAY          100     /* Wait 100us before polling EC again */

#define ACPI_EC_STORM_THRESHOLD 8       /* number of false interrupts
                                           per one transaction */

enum {
        EC_FLAGS_QUERY_PENDING,         /* Query is pending */
        EC_FLAGS_GPE_MODE,              /* Expect GPE to be sent
                                         * for status change */
        EC_FLAGS_NO_GPE,                /* Don't use GPE mode */
        EC_FLAGS_GPE_STORM,             /* GPE storm detected */
        EC_FLAGS_HANDLERS_INSTALLED     /* Handlers for GPE and
                                         * OpReg are installed */
};

/* 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;
};

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;
        struct transaction *curr;
        spinlock_t curr_lock;
} *boot_ec, *first_ec;

/* 
 * Some Asus system have exchanged ECDT data/command IO addresses.
 */
static int print_ecdt_error(const struct dmi_system_id *id)
{
        printk(KERN_NOTICE PREFIX "%s detected - "
                "ECDT has exchanged control/data I/O address\n",
                id->ident);
        return 0;
}

static struct dmi_system_id __cpuinitdata ec_dmi_table[] = {
        {
        print_ecdt_error, "Asus L4R", {
        DMI_MATCH(DMI_BIOS_VERSION, "1008.006"),
        DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),
        DMI_MATCH(DMI_BOARD_NAME, "L4R") }, NULL},
        {
        print_ecdt_error, "Asus M6R", {
        DMI_MATCH(DMI_BIOS_VERSION, "0207"),
        DMI_MATCH(DMI_PRODUCT_NAME, "M6R"),
        DMI_MATCH(DMI_BOARD_NAME, "M6R") }, NULL},
        {},
};

/* --------------------------------------------------------------------------
                             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 gpe_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_wait(struct acpi_ec *ec)
{
        if (wait_event_timeout(ec->wait, ec_transaction_done(ec),
                               msecs_to_jiffies(ACPI_EC_DELAY)))
                return 0;
        /* try restart command if we get any false interrupts */
        if (ec->curr->irq_count &&
            (acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF) == 0) {
                pr_debug(PREFIX "controller reset, restart transaction\n");
                start_transaction(ec);
                if (wait_event_timeout(ec->wait, ec_transaction_done(ec),
                                        msecs_to_jiffies(ACPI_EC_DELAY)))
                        return 0;
        }
        /* missing GPEs, switch back to poll mode */
        if (printk_ratelimit())
                pr_info(PREFIX "missing confirmations, "
                                "switch off interrupt mode.\n");
        set_bit(EC_FLAGS_NO_GPE, &ec->flags);
        clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
        return 1;
}

static void acpi_ec_gpe_query(void *ec_cxt);

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))
                        return acpi_os_execute(OSL_EC_BURST_HANDLER,
                                acpi_ec_gpe_query, ec);
        }
        return 0;
}

static int ec_poll(struct acpi_ec *ec)
{
        unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
        udelay(ACPI_EC_UDELAY);
        while (time_before(jiffies, delay)) {
                gpe_transaction(ec, acpi_ec_read_status(ec));
                udelay(ACPI_EC_UDELAY);
                if (ec_transaction_done(ec))
                        return 0;
        }
        return -ETIME;
}

static int acpi_ec_transaction_unlocked(struct acpi_ec *ec,
                                        struct transaction *t,
                                        int force_poll)
{
        unsigned long tmp;
        int ret = 0;
        pr_debug(PREFIX "transaction start\n");
        /* disable GPE during transaction if storm is detected */
        if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
                clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
                acpi_disable_gpe(NULL, ec->gpe);
        }
        /* 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);
        /* if we selected poll mode or failed in GPE-mode do a poll loop */
        if (force_poll ||
            !test_bit(EC_FLAGS_GPE_MODE, &ec->flags) ||
            acpi_ec_wait(ec))
                ret = ec_poll(ec);
        pr_debug(PREFIX "transaction end\n");
        spin_lock_irqsave(&ec->curr_lock, tmp);
        ec->curr = NULL;
        spin_unlock_irqrestore(&ec->curr_lock, tmp);
        if (test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
                /* check if we received SCI during transaction */
                ec_check_sci(ec, acpi_ec_read_status(ec));
                /* it is safe to enable GPE outside of transaction */
                acpi_enable_gpe(NULL, ec->gpe);
        } else if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&
                   t->irq_count > ACPI_EC_STORM_THRESHOLD) {
                pr_info(PREFIX "GPE storm detected, "
                        "transactions will use polling mode\n");
                set_bit(EC_FLAGS_GPE_STORM, &ec->flags);
        }
        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(ACPI_EC_DELAY);
        /* interrupt wait manually if GPE mode is not active */
        unsigned long timeout = test_bit(EC_FLAGS_GPE_MODE, &ec->flags) ?
                msecs_to_jiffies(ACPI_EC_DELAY) : msecs_to_jiffies(1);
        while (time_before(jiffies, delay))
                if (wait_event_timeout(ec->wait, ec_check_ibf0(ec), timeout))
                        return 0;
        return -ETIME;
}

static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t,
                               int force_poll)
{
        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 (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;
        }
        status = acpi_ec_transaction_unlocked(ec, t, force_poll);
end:
        if (ec->global_lock)
                acpi_release_global_lock(glk);
unlock:
        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;
        struct transaction t = {.command = ACPI_EC_BURST_ENABLE,
                                .wdata = NULL, .rdata = &d,
                                .wlen = 0, .rlen = 1};

        return acpi_ec_transaction(ec, &t, 0);
}

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) : 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, 0);
        *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, 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)
{
        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, force_poll);
}

EXPORT_SYMBOL(ec_transaction);

static int acpi_ec_query(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(ec, &t, 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);

static void acpi_ec_gpe_query(void *ec_cxt)
{
        struct acpi_ec *ec = ec_cxt;
        u8 value = 0;
        struct acpi_ec_query_handler *handler, copy;

        if (!ec || acpi_ec_query(ec, &value))
                return;
        mutex_lock(&ec->lock);
        list_for_each_entry(handler, &ec->list, node) {
                if (value == handler->query_bit) {
                        /* have custom handler for this bit */
                        memcpy(&copy, handler, sizeof(copy));
                        mutex_unlock(&ec->lock);
                        if (copy.func) {
                                copy.func(copy.data);
                        } else if (copy.handle) {
                                acpi_evaluate_object(copy.handle, NULL, NULL, NULL);
                        }
                        return;
                }
        }
        mutex_unlock(&ec->lock);
}

static u32 acpi_ec_gpe_handler(void *data)
{
        struct acpi_ec *ec = data;
        u8 status;

        pr_debug(PREFIX "~~~> interrupt\n");
        status = acpi_ec_read_status(ec);

        if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) {
                gpe_transaction(ec, status);
                if (ec_transaction_done(ec) &&
                    (status & ACPI_EC_FLAG_IBF) == 0)
                        wake_up(&ec->wait);
        }

        ec_check_sci(ec, status);
        if (!test_bit(EC_FLAGS_GPE_MODE, &ec->flags) &&
            !test_bit(EC_FLAGS_NO_GPE, &ec->flags)) {
                /* this is non-query, must be confirmation */
                if (!test_bit(EC_FLAGS_GPE_STORM, &ec->flags)) {
                        if (printk_ratelimit())
                                pr_info(PREFIX "non-query interrupt received,"
                                        " switching to interrupt mode\n");
                } else {
                        /* hush, STORM switches the mode every transaction */
                        pr_debug(PREFIX "non-query interrupt received,"
                                " switching to interrupt mode\n");
                }
                set_bit(EC_FLAGS_GPE_MODE, &ec->flags);
        }
        return ACPI_INTERRUPT_HANDLED;
}

/* --------------------------------------------------------------------------
                             Address Space Management
   -------------------------------------------------------------------------- */

static acpi_status
acpi_ec_space_handler(u32 function, acpi_physical_address address,
                      u32 bits, acpi_integer *value,
                      void *handler_context, void *region_context)
{
        struct acpi_ec *ec = handler_context;
        int result = 0, i;
        u8 temp = 0;

        if ((address > 0xFF) || !value || !handler_context)
                return AE_BAD_PARAMETER;

        if (function != ACPI_READ && function != ACPI_WRITE)
                return AE_BAD_PARAMETER;

        if (bits != 8 && acpi_strict)
                return AE_BAD_PARAMETER;

        acpi_ec_burst_enable(ec);

        if (function == ACPI_READ) {
                result = acpi_ec_read(ec, address, &temp);
                *value = temp;
        } else {
                temp = 0xff & (*value);
                result = acpi_ec_write(ec, address, temp);
        }

        for (i = 8; unlikely(bits - i > 0); i += 8) {
                ++address;
                if (function == ACPI_READ) {
                        result = acpi_ec_read(ec, address, &temp);
                        (*value) |= ((acpi_integer)temp) << i;
                } else {
                        temp = 0xff & ((*value) >> i);
                        result = acpi_ec_write(ec, address, temp);
                }
        }

        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;
        }
}

/* --------------------------------------------------------------------------
                              FS Interface (/proc)
   -------------------------------------------------------------------------- */

static struct proc_dir_entry *acpi_ec_dir;

static int acpi_ec_read_info(struct seq_file *seq, void *offset)
{
        struct acpi_ec *ec = seq->private;

        if (!ec)
                goto end;

        seq_printf(seq, "gpe:\t\t\t0x%02x\n", (u32) ec->gpe);
        seq_printf(seq, "ports:\t\t\t0x%02x, 0x%02x\n",
                   (unsigned)ec->command_addr, (unsigned)ec->data_addr);
        seq_printf(seq, "use global lock:\t%s\n",
                   ec->global_lock ? "yes" : "no");
      end:
        return 0;
}

static int acpi_ec_info_open_fs(struct inode *inode, struct file *file)
{
        return single_open(file, acpi_ec_read_info, PDE(inode)->data);
}

static struct file_operations acpi_ec_info_ops = {
        .open = acpi_ec_info_open_fs,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
        .owner = THIS_MODULE,
};

static int acpi_ec_add_fs(struct acpi_device *device)
{
        struct proc_dir_entry *entry = NULL;

        if (!acpi_device_dir(device)) {
                acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
                                                     acpi_ec_dir);
                if (!acpi_device_dir(device))
                        return -ENODEV;
        }

        entry = proc_create_data(ACPI_EC_FILE_INFO, S_IRUGO,
                                 acpi_device_dir(device),
                                 &acpi_ec_info_ops, acpi_driver_data(device));
        if (!entry)
                return -ENODEV;
        return 0;
}

static int acpi_ec_remove_fs(struct acpi_device *device)
{

        if (acpi_device_dir(device)) {
                remove_proc_entry(ACPI_EC_FILE_INFO, acpi_device_dir(device));
                remove_proc_entry(acpi_device_bid(device), acpi_ec_dir);
                acpi_device_dir(device) = NULL;
        }

        return 0;
}

/* --------------------------------------------------------------------------
                               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)
{
        struct acpi_namespace_node *node = handle;
        struct acpi_ec *ec = context;
        int value = 0;
        if (sscanf(node->name.ascii, "_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;
        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 void ec_remove_handlers(struct acpi_ec *ec)
{
        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;

        if (!device)
                return -EINVAL;
        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;
                }
        }

        ec->handle = device->handle;

        /* Find and register all query methods */
        acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
                            acpi_ec_register_query_methods, ec, NULL);

        if (!first_ec)
                first_ec = ec;
        device->driver_data = ec;
        acpi_ec_add_fs(device);
        pr_info(PREFIX "GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
                          ec->gpe, ec->command_addr, ec->data_addr);
        pr_info(PREFIX "driver started in %s mode\n",
                (test_bit(EC_FLAGS_GPE_MODE, &ec->flags))?"interrupt":"poll");
        return 0;
}

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);
        mutex_lock(&ec->lock);
        list_for_each_entry_safe(handler, tmp, &ec->list, node) {
                list_del(&handler->node);
                kfree(handler);
        }
        mutex_unlock(&ec->lock);
        acpi_ec_remove_fs(device);
        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;
}

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_set_gpe_type(NULL, ec->gpe, ACPI_GPE_TYPE_RUNTIME);
        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);
                        return -ENODEV;
                }
        }

        set_bit(EC_FLAGS_HANDLERS_INSTALLED, &ec->flags);
        return 0;
}

static int acpi_ec_start(struct acpi_device *device)
{
        struct acpi_ec *ec;
        int ret = 0;

        if (!device)
                return -EINVAL;

        ec = acpi_driver_data(device);

        if (!ec)
                return -EINVAL;

        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_stop(struct acpi_device *device, int type)
{
        struct acpi_ec *ec;
        if (!device)
                return -EINVAL;
        ec = acpi_driver_data(device);
        if (!ec)
                return -EINVAL;
        ec_remove_handlers(ec);

        return 0;
}

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},
};

int __init acpi_ec_ecdt_probe(void)
{
        int ret;
        acpi_status status;
        struct acpi_table_ecdt *ecdt_ptr;

        boot_ec = make_acpi_ec();
        if (!boot_ec)
                return -ENOMEM;
        /*
         * Generate a boot ec context
         */
        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;
                if (dmi_check_system(ec_dmi_table)) {
                        /*
                         * If the board falls into ec_dmi_table, it means
                         * that ECDT table gives the incorrect command/status
                         * & data I/O address. Just fix it.
                         */
                        boot_ec->data_addr = ecdt_ptr->control.address;
                        boot_ec->command_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);
        } else {
                /* This workaround is needed only on some broken machines,
                 * which require early EC, but fail to provide ECDT */
                acpi_handle x;
                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;
                /* 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.
                 */
                if (ACPI_FAILURE(acpi_get_handle(boot_ec->handle, "_INI", &x)))
                        return -ENODEV;
        }

        ret = ec_install_handlers(boot_ec);
        if (!ret) {
                first_ec = boot_ec;
                return 0;
        }
      error:
        kfree(boot_ec);
        boot_ec = NULL;
        return -ENODEV;
}

static int acpi_ec_suspend(struct acpi_device *device, pm_message_t state)
{
        struct acpi_ec *ec = acpi_driver_data(device);
        /* Stop using GPE */
        set_bit(EC_FLAGS_NO_GPE, &ec->flags);
        clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
        acpi_disable_gpe(NULL, ec->gpe);
        return 0;
}

static int acpi_ec_resume(struct acpi_device *device)
{
        struct acpi_ec *ec = acpi_driver_data(device);
        /* Enable use of GPE back */
        clear_bit(EC_FLAGS_NO_GPE, &ec->flags);
        acpi_enable_gpe(NULL, ec->gpe);
        return 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,
                .suspend = acpi_ec_suspend,
                .resume = acpi_ec_resume,
                },
};

static int __init acpi_ec_init(void)
{
        int result = 0;

        if (acpi_disabled)
                return 0;

        acpi_ec_dir = proc_mkdir(ACPI_EC_CLASS, acpi_root_dir);
        if (!acpi_ec_dir)
                return -ENODEV;

        /* Now register the driver for the EC */
        result = acpi_bus_register_driver(&acpi_ec_driver);
        if (result < 0) {
                remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);
                return -ENODEV;
        }

        return result;
}

subsys_initcall(acpi_ec_init);

/* EC driver currently not unloadable */
#if 0
static void __exit acpi_ec_exit(void)
{

        acpi_bus_unregister_driver(&acpi_ec_driver);

        remove_proc_entry(ACPI_EC_CLASS, acpi_root_dir);

        return;
}
#endif  /* 0 */