Kbuild/doc: fix links to Documentation files
[safe/jmp/linux-2.6] / drivers / acpi / ec.c
index 82f496c..06b78e5 100644 (file)
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/interrupt.h>
+#include <linux/list.h>
 #include <asm/io.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 #include <acpi/actypes.h>
 
-#define _COMPONENT             ACPI_EC_COMPONENT
-ACPI_MODULE_NAME("ec");
-#define ACPI_EC_COMPONENT              0x00100000
 #define ACPI_EC_CLASS                  "embedded_controller"
-#define ACPI_EC_HID                    "PNP0C09"
 #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,
@@ -61,29 +61,37 @@ enum ec_command {
        ACPI_EC_BURST_DISABLE = 0x83,
        ACPI_EC_COMMAND_QUERY = 0x84,
 };
+
 /* EC events */
 enum ec_event {
        ACPI_EC_EVENT_OBF_1 = 1,        /* Output buffer full */
-       ACPI_EC_EVENT_IBF_0,    /* Input buffer empty */
+       ACPI_EC_EVENT_IBF_0,            /* Input buffer empty */
 };
 
 #define ACPI_EC_DELAY          500     /* Wait 500ms max. during EC ops */
 #define ACPI_EC_UDELAY_GLK     1000    /* Wait 1ms max. to get global lock */
 
-static enum ec_mode {
-       EC_INTR = 1,            /* Output buffer full */
-       EC_POLL,                /* Input buffer empty */
-} acpi_ec_mode = EC_INTR;
+enum {
+       EC_FLAGS_WAIT_GPE = 0,          /* Don't check status until GPE arrives */
+       EC_FLAGS_QUERY_PENDING,         /* Query is pending */
+       EC_FLAGS_GPE_MODE,              /* Expect GPE to be sent for status change */
+       EC_FLAGS_ONLY_IBF_GPE,          /* Expect GPE only for IBF = 0 event */
+};
 
 static int acpi_ec_remove(struct acpi_device *device, int type);
 static int acpi_ec_start(struct acpi_device *device);
 static int acpi_ec_stop(struct acpi_device *device, int type);
 static int acpi_ec_add(struct acpi_device *device);
 
+static const struct acpi_device_id ec_device_ids[] = {
+       {"PNP0C09", 0},
+       {"", 0},
+};
+
 static struct acpi_driver acpi_ec_driver = {
        .name = "ec",
        .class = ACPI_EC_CLASS,
-       .ids = ACPI_EC_HID,
+       .ids = ec_device_ids,
        .ops = {
                .add = acpi_ec_add,
                .remove = acpi_ec_remove,
@@ -94,16 +102,27 @@ static struct acpi_driver acpi_ec_driver = {
 
 /* If we find an EC via the ECDT, we need to keep a ptr to its context */
 /* External interfaces use first EC only, so remember */
+typedef int (*acpi_ec_query_func) (void *data);
+
+struct acpi_ec_query_handler {
+       struct list_head node;
+       acpi_ec_query_func func;
+       acpi_handle handle;
+       void *data;
+       u8 query_bit;
+};
+
 static struct acpi_ec {
        acpi_handle handle;
        unsigned long gpe;
        unsigned long command_addr;
        unsigned long data_addr;
        unsigned long global_lock;
+       unsigned long flags;
        struct mutex lock;
-       atomic_t query_pending;
-       atomic_t event_count;
        wait_queue_head_t wait;
+       struct list_head list;
+       u8 handlers_installed;
 } *boot_ec, *first_ec;
 
 /* --------------------------------------------------------------------------
@@ -130,45 +149,54 @@ static inline void acpi_ec_write_data(struct acpi_ec *ec, u8 data)
        outb(data, ec->data_addr);
 }
 
-static inline int acpi_ec_check_status(struct acpi_ec *ec, enum ec_event event,
-                                      unsigned old_count)
+static inline int acpi_ec_check_status(struct acpi_ec *ec, enum ec_event event)
 {
-       u8 status = acpi_ec_read_status(ec);
-       if (old_count == atomic_read(&ec->event_count))
+       if (test_bit(EC_FLAGS_WAIT_GPE, &ec->flags))
                return 0;
        if (event == ACPI_EC_EVENT_OBF_1) {
-               if (status & ACPI_EC_FLAG_OBF)
+               if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_OBF)
                        return 1;
        } else if (event == ACPI_EC_EVENT_IBF_0) {
-               if (!(status & ACPI_EC_FLAG_IBF))
+               if (!(acpi_ec_read_status(ec) & ACPI_EC_FLAG_IBF))
                        return 1;
        }
 
        return 0;
 }
 
-static int acpi_ec_wait(struct acpi_ec *ec, enum ec_event event,
-                        unsigned count, int force_poll)
+static int acpi_ec_wait(struct acpi_ec *ec, enum ec_event event, int force_poll)
 {
-       if (unlikely(force_poll) || acpi_ec_mode == EC_POLL) {
+       if (likely(test_bit(EC_FLAGS_GPE_MODE, &ec->flags)) &&
+           likely(!force_poll)) {
+               if (wait_event_timeout(ec->wait, acpi_ec_check_status(ec, event),
+                                      msecs_to_jiffies(ACPI_EC_DELAY)))
+                       return 0;
+               clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
+               if (acpi_ec_check_status(ec, event)) {
+                       if (event == ACPI_EC_EVENT_OBF_1) {
+                               /* miss OBF = 1 GPE, don't expect it anymore */
+                               printk(KERN_INFO PREFIX "missing OBF_1 confirmation,"
+                                       "switching to degraded mode.\n");
+                               set_bit(EC_FLAGS_ONLY_IBF_GPE, &ec->flags);
+                       } else {
+                               /* missing GPEs, switch back to poll mode */
+                               printk(KERN_INFO PREFIX "missing IBF_1 confirmations,"
+                                       "switch off interrupt mode.\n");
+                               clear_bit(EC_FLAGS_GPE_MODE, &ec->flags);
+                       }
+                       return 0;
+               }
+       } else {
                unsigned long delay = jiffies + msecs_to_jiffies(ACPI_EC_DELAY);
+               clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
                while (time_before(jiffies, delay)) {
-                       if (acpi_ec_check_status(ec, event, 0))
+                       if (acpi_ec_check_status(ec, event))
                                return 0;
                }
-       } else {
-               if (wait_event_timeout(ec->wait,
-                                      acpi_ec_check_status(ec, event, count),
-                                      msecs_to_jiffies(ACPI_EC_DELAY)) ||
-                   acpi_ec_check_status(ec, event, 0)) {
-                       return 0;
-               } else {
-                       printk(KERN_ERR PREFIX "acpi_ec_wait timeout,"
+       }
+       printk(KERN_ERR PREFIX "acpi_ec_wait timeout,"
                               " status = %d, expect_event = %d\n",
                               acpi_ec_read_status(ec), event);
-               }
-       }
-
        return -ETIME;
 }
 
@@ -178,39 +206,42 @@ static int acpi_ec_transaction_unlocked(struct acpi_ec *ec, u8 command,
                                        int force_poll)
 {
        int result = 0;
-       unsigned count = atomic_read(&ec->event_count);
+       set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
        acpi_ec_write_cmd(ec, command);
 
        for (; wdata_len > 0; --wdata_len) {
-               result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, count, force_poll);
+               result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);
                if (result) {
                        printk(KERN_ERR PREFIX
                               "write_cmd timeout, command = %d\n", command);
                        goto end;
                }
-               count = atomic_read(&ec->event_count);
+               set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
                acpi_ec_write_data(ec, *(wdata++));
        }
 
        if (!rdata_len) {
-               result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, count, force_poll);
+               result = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, force_poll);
                if (result) {
                        printk(KERN_ERR PREFIX
                               "finish-write timeout, command = %d\n", command);
                        goto end;
                }
-       } else if (command == ACPI_EC_COMMAND_QUERY) {
-               atomic_set(&ec->query_pending, 0);
-       }
+       } else if (command == ACPI_EC_COMMAND_QUERY)
+               clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
 
        for (; rdata_len > 0; --rdata_len) {
-               result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1, count, force_poll);
+               if (test_bit(EC_FLAGS_ONLY_IBF_GPE, &ec->flags))
+                       force_poll = 1;
+               result = acpi_ec_wait(ec, ACPI_EC_EVENT_OBF_1, force_poll);
                if (result) {
                        printk(KERN_ERR PREFIX "read timeout, command = %d\n",
                               command);
                        goto end;
                }
-               count = atomic_read(&ec->event_count);
+               /* Don't expect GPE after last read */
+               if (rdata_len > 1)
+                       set_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
                *(rdata++) = acpi_ec_read_data(ec);
        }
       end:
@@ -240,12 +271,9 @@ static int acpi_ec_transaction(struct acpi_ec *ec, u8 command,
                }
        }
 
-       /* Make sure GPE is enabled before doing transaction */
-       acpi_enable_gpe(NULL, ec->gpe, ACPI_NOT_ISR);
-
-       status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, 0, 0);
+       status = acpi_ec_wait(ec, ACPI_EC_EVENT_IBF_0, 0);
        if (status) {
-               printk(KERN_DEBUG PREFIX
+               printk(KERN_ERR PREFIX
                       "input buffer is not empty, aborting transaction\n");
                goto end;
        }
@@ -394,44 +422,88 @@ static int acpi_ec_query(struct acpi_ec *ec, u8 * data)
 /* --------------------------------------------------------------------------
                                 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;
-       char object_name[8];
+       struct acpi_ec_query_handler *handler, copy;
 
        if (!ec || acpi_ec_query(ec, &value))
                return;
-
-       snprintf(object_name, 8, "_Q%2.2X", value);
-
-       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Evaluating %s", object_name));
-
-       acpi_evaluate_object(ec->handle, object_name, NULL, NULL);
+       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)
 {
        acpi_status status = AE_OK;
-       u8 value;
        struct acpi_ec *ec = data;
 
-       atomic_inc(&ec->event_count);
-
-       if (acpi_ec_mode == EC_INTR) {
+       clear_bit(EC_FLAGS_WAIT_GPE, &ec->flags);
+       if (test_bit(EC_FLAGS_GPE_MODE, &ec->flags))
                wake_up(&ec->wait);
-       }
 
-       value = acpi_ec_read_status(ec);
-       if ((value & ACPI_EC_FLAG_SCI) && !atomic_read(&ec->query_pending)) {
-               atomic_set(&ec->query_pending, 1);
-               status =
-                   acpi_os_execute(OSL_EC_BURST_HANDLER, acpi_ec_gpe_query,
-                                   ec);
+       if (acpi_ec_read_status(ec) & ACPI_EC_FLAG_SCI) {
+               if (!test_and_set_bit(EC_FLAGS_QUERY_PENDING, &ec->flags))
+                       status = acpi_os_execute(OSL_EC_BURST_HANDLER,
+                               acpi_ec_gpe_query, ec);
+       } else if (unlikely(!test_bit(EC_FLAGS_GPE_MODE, &ec->flags))) {
+               /* this is non-query, must be confirmation */
+               printk(KERN_INFO PREFIX "non-query interrupt received,"
+                       " switching to interrupt mode\n");
+               set_bit(EC_FLAGS_GPE_MODE, &ec->flags);
        }
 
-       return status == AE_OK ?
+       return ACPI_SUCCESS(status) ?
            ACPI_INTERRUPT_HANDLED : ACPI_INTERRUPT_NOT_HANDLED;
 }
 
@@ -454,57 +526,35 @@ acpi_ec_space_setup(acpi_handle region_handle,
 }
 
 static acpi_status
-acpi_ec_space_handler(u32 function,
-                     acpi_physical_address address,
-                     u32 bit_width,
-                     acpi_integer * value,
+acpi_ec_space_handler(u32 function, acpi_physical_address address,
+                     u32 bits, acpi_integer *value,
                      void *handler_context, void *region_context)
 {
-       int result = 0;
        struct acpi_ec *ec = handler_context;
-       u64 temp = *value;
-       acpi_integer f_v = 0;
-       int i = 0;
+       int result = 0, i = 0;
+       u8 temp = 0;
 
        if ((address > 0xFF) || !value || !handler_context)
                return AE_BAD_PARAMETER;
 
-       if (bit_width != 8 && acpi_strict) {
+       if (function != ACPI_READ && function != ACPI_WRITE)
                return AE_BAD_PARAMETER;
-       }
 
-      next_byte:
-       switch (function) {
-       case ACPI_READ:
-               temp = 0;
-               result = acpi_ec_read(ec, (u8) address, (u8 *) & temp);
-               break;
-       case ACPI_WRITE:
-               result = acpi_ec_write(ec, (u8) address, (u8) temp);
-               break;
-       default:
-               result = -EINVAL;
-               goto out;
-               break;
-       }
-
-       bit_width -= 8;
-       if (bit_width) {
-               if (function == ACPI_READ)
-                       f_v |= temp << 8 * i;
-               if (function == ACPI_WRITE)
-                       temp >>= 8;
-               i++;
-               address++;
-               goto next_byte;
-       }
+       if (bits != 8 && acpi_strict)
+               return AE_BAD_PARAMETER;
 
-       if (function == ACPI_READ) {
-               f_v |= temp << 8 * i;
-               *value = f_v;
+       while (bits - i > 0) {
+               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);
+               }
+               i += 8;
+               ++address;
        }
 
-      out:
        switch (result) {
        case -EINVAL:
                return AE_BAD_PARAMETER;
@@ -597,84 +647,133 @@ static int acpi_ec_remove_fs(struct acpi_device *device)
 static acpi_status
 ec_parse_io_ports(struct acpi_resource *resource, void *context);
 
-static acpi_status
-ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval);
-
 static struct acpi_ec *make_acpi_ec(void)
 {
        struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
        if (!ec)
                return NULL;
-
-       atomic_set(&ec->query_pending, 1);
-       atomic_set(&ec->event_count, 1);
+       ec->flags = 1 << EC_FLAGS_QUERY_PENDING;
        mutex_init(&ec->lock);
        init_waitqueue_head(&ec->wait);
-
+       INIT_LIST_HEAD(&ec->list);
        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;
+
+       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, &ec->gpe);
+       if (ACPI_FAILURE(status))
+               return status;
+       /* Find and register all query methods */
+       acpi_walk_namespace(ACPI_TYPE_METHOD, handle, 1,
+                           acpi_ec_register_query_methods, ec, NULL);
+       /* Use the global lock for all EC transactions? */
+       acpi_evaluate_integer(handle, "_GLK", NULL, &ec->global_lock);
+       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)))
+               printk(KERN_ERR PREFIX "failed to remove space handler\n");
+       if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
+                               &acpi_ec_gpe_handler)))
+               printk(KERN_ERR PREFIX "failed to remove gpe handler\n");
+       ec->handlers_installed = 0;
+}
+
 static int acpi_ec_add(struct acpi_device *device)
 {
-       acpi_status status = AE_OK;
        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) {
+               if (boot_ec->handle == device->handle) {
+                       /* Pre-loaded EC from DSDT, just move pointer */
+                       ec = boot_ec;
+                       boot_ec = NULL;
+                       goto end;
+               } else if (boot_ec->handle == ACPI_ROOT_OBJECT) {
+                       /* ECDT-based EC, time to shut it down */
+                       ec_remove_handlers(boot_ec);
+                       kfree(boot_ec);
+                       first_ec = boot_ec = NULL;
+               }
+       }
+
        ec = make_acpi_ec();
        if (!ec)
                return -ENOMEM;
 
-       status = ec_parse_device(device->handle, 0, ec, NULL);
-       if (status != AE_CTRL_TERMINATE) {
+       if (ec_parse_device(device->handle, 0, ec, NULL) !=
+           AE_CTRL_TERMINATE) {
                kfree(ec);
                return -EINVAL;
        }
-
-       /* Check if we found the boot EC */
-       if (boot_ec) {
-               if (boot_ec->gpe == ec->gpe) {
-                       /* We might have incorrect info for GL at boot time */
-                       mutex_lock(&boot_ec->lock);
-                       boot_ec->global_lock = ec->global_lock;
-                       mutex_unlock(&boot_ec->lock);
-                       kfree(ec);
-                       ec = boot_ec;
-               }
-       } else
-               first_ec = ec;
        ec->handle = device->handle;
+      end:
+       if (!first_ec)
+               first_ec = ec;
        acpi_driver_data(device) = ec;
-
        acpi_ec_add_fs(device);
-
-       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s [%s] (gpe %d) interrupt mode.",
-                         acpi_device_name(device), acpi_device_bid(device),
-                         (u32) ec->gpe));
-
+       printk(KERN_INFO PREFIX "GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
+                         ec->gpe, ec->command_addr, ec->data_addr);
+       printk(KERN_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);
        acpi_driver_data(device) = NULL;
        if (ec == first_ec)
                first_ec = NULL;
-
-       /* Don't touch boot EC */
-       if (boot_ec != ec)
-               kfree(ec);
+       kfree(ec);
        return 0;
 }
 
@@ -704,6 +803,8 @@ ec_parse_io_ports(struct acpi_resource *resource, void *context)
 static int ec_install_handlers(struct acpi_ec *ec)
 {
        acpi_status status;
+       if (ec->handlers_installed)
+               return 0;
        status = acpi_install_gpe_handler(NULL, ec->gpe,
                                          ACPI_GPE_EDGE_TRIGGERED,
                                          &acpi_ec_gpe_handler, ec);
@@ -722,15 +823,14 @@ static int ec_install_handlers(struct acpi_ec *ec)
                return -ENODEV;
        }
 
-       /* EC is fully operational, allow queries */
-       atomic_set(&ec->query_pending, 0);
-
+       ec->handlers_installed = 1;
        return 0;
 }
 
 static int acpi_ec_start(struct acpi_device *device)
 {
        struct acpi_ec *ec;
+       int ret = 0;
 
        if (!device)
                return -EINVAL;
@@ -740,73 +840,26 @@ static int acpi_ec_start(struct acpi_device *device)
        if (!ec)
                return -EINVAL;
 
-       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "gpe=0x%02lx, ports=0x%2lx,0x%2lx",
-                         ec->gpe, ec->command_addr, ec->data_addr));
+       ret = ec_install_handlers(ec);
 
-       /* Boot EC is already working */
-       if (ec == boot_ec)
-               return 0;
-
-       return 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)
 {
-       acpi_status status;
        struct acpi_ec *ec;
-
        if (!device)
                return -EINVAL;
-
        ec = acpi_driver_data(device);
        if (!ec)
                return -EINVAL;
-
-       /* Don't touch boot EC */
-       if (ec == boot_ec)
-               return 0;
-
-       status = acpi_remove_address_space_handler(ec->handle,
-                                                  ACPI_ADR_SPACE_EC,
-                                                  &acpi_ec_space_handler);
-       if (ACPI_FAILURE(status))
-               return -ENODEV;
-
-       status = acpi_remove_gpe_handler(NULL, ec->gpe, &acpi_ec_gpe_handler);
-       if (ACPI_FAILURE(status))
-               return -ENODEV;
+       ec_remove_handlers(ec);
 
        return 0;
 }
 
-static acpi_status
-ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
-{
-       acpi_status status;
-
-       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, &ec->gpe);
-       if (ACPI_FAILURE(status))
-               return status;
-
-       /* Use the global lock for all EC transactions? */
-       acpi_evaluate_integer(handle, "_GLK", NULL, &ec->global_lock);
-
-       ec->handle = handle;
-
-       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "GPE=0x%02lx, ports=0x%2lx, 0x%2lx",
-                         ec->gpe, ec->command_addr, ec->data_addr));
-
-       return AE_CTRL_TERMINATE;
-}
-
 int __init acpi_ec_ecdt_probe(void)
 {
        int ret;
@@ -819,18 +872,22 @@ int __init acpi_ec_ecdt_probe(void)
        /*
         * Generate a boot ec context
         */
-
        status = acpi_get_table(ACPI_SIG_ECDT, 1,
                                (struct acpi_table_header **)&ecdt_ptr);
-       if (ACPI_FAILURE(status))
-               goto error;
-
-       ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found ECDT"));
-
-       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;
+       if (ACPI_SUCCESS(status)) {
+               printk(KERN_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;
+       } else {
+               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;
+       }
 
        ret = ec_install_handlers(boot_ec);
        if (!ret) {
@@ -840,7 +897,6 @@ int __init acpi_ec_ecdt_probe(void)
       error:
        kfree(boot_ec);
        boot_ec = NULL;
-
        return -ENODEV;
 }
 
@@ -878,20 +934,4 @@ static void __exit acpi_ec_exit(void)
 
        return;
 }
-#endif                         /* 0 */
-
-static int __init acpi_ec_set_intr_mode(char *str)
-{
-       int intr;
-
-       if (!get_option(&str, &intr))
-               return 0;
-
-       acpi_ec_mode = (intr) ? EC_INTR : EC_POLL;
-
-       printk(KERN_NOTICE PREFIX "%s mode.\n", intr ? "interrupt" : "polling");
-
-       return 1;
-}
-
-__setup("ec_intr=", acpi_ec_set_intr_mode);
+#endif /* 0 */