ACPICA: Implicit notify support

This feature provides an automatic device notification for wake devices
when a wakeup GPE occurs and there is no corresponding GPE method or
handler. Rather than ignoring such a GPE, an implicit AML Notify
operation is performed on the parent device object.
This feature is not part of the ACPI specification and is provided for
Windows compatibility only.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

8 files changed, 161 insertions, 88 deletions

diff --git a/drivers/acpi/acpica/acevents.h b/drivers/acpi/acpica/acevents.h
index 04a83fe47d6f..70e0b28801aa 100644
--- a/drivers/acpi/acpica/acevents.h
+++ b/drivers/acpi/acpica/acevents.h
@@ -91,6 +91,8 @@ struct acpi_gpe_event_info *acpi_ev_low_get_gpe_info(u32 gpe_number,
                                                      struct acpi_gpe_block_info
                                                      *gpe_block);
 
+acpi_status acpi_ev_finish_gpe(struct acpi_gpe_event_info *gpe_event_info);
+
 /*
  * evgpeblk - Upper-level GPE block support
  */
diff --git a/drivers/acpi/acpica/aclocal.h b/drivers/acpi/acpica/aclocal.h
index 6a71f8e673e9..74000f5b7dab 100644
--- a/drivers/acpi/acpica/aclocal.h
+++ b/drivers/acpi/acpica/aclocal.h
@@ -419,6 +419,7 @@ struct acpi_gpe_handler_info {
 union acpi_gpe_dispatch_info {
         struct acpi_namespace_node *method_node;        /* Method node for this GPE level */
         struct acpi_gpe_handler_info *handler;  /* Installed GPE handler */
+        struct acpi_namespace_node *device_node;        /* Parent _PRW device for implicit notify */
 };
 
 /*
diff --git a/drivers/acpi/acpica/evgpe.c b/drivers/acpi/acpica/evgpe.c
index c25999546c8c..2dbca95979ce 100644
--- a/drivers/acpi/acpica/evgpe.c
+++ b/drivers/acpi/acpica/evgpe.c
@@ -115,12 +115,13 @@ acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
         ACPI_FUNCTION_TRACE(ev_enable_gpe);
 
         /*
-         * We will only allow a GPE to be enabled if it has either an
-         * associated method (_Lxx/_Exx) or a handler. Otherwise, the
-         * GPE will be immediately disabled by acpi_ev_gpe_dispatch the
-         * first time it fires.
+         * We will only allow a GPE to be enabled if it has either an associated
+         * method (_Lxx/_Exx) or a handler, or is using the implicit notify
+         * feature. Otherwise, the GPE will be immediately disabled by
+         * acpi_ev_gpe_dispatch the first time it fires.
          */
-        if (!(gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK)) {
+        if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
+            ACPI_GPE_DISPATCH_NONE) {
                 return_ACPI_STATUS(AE_NO_HANDLER);
         }
 
@@ -486,12 +487,26 @@ static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
                 return_VOID;
         }
 
-        /*
-         * Must check for control method type dispatch one more time to avoid a
-         * race with ev_gpe_install_handler
-         */
-        if ((local_gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
-            ACPI_GPE_DISPATCH_METHOD) {
+        /* Do the correct dispatch - normal method or implicit notify */
+
+        switch (local_gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) {
+        case ACPI_GPE_DISPATCH_NOTIFY:
+
+                /*
+                 * Implicit notify.
+                 * Dispatch a DEVICE_WAKE notify to the appropriate handler.
+                 * NOTE: the request is queued for execution after this method
+                 * completes. The notify handlers are NOT invoked synchronously
+                 * from this thread -- because handlers may in turn run other
+                 * control methods.
+                 */
+                status =
+                    acpi_ev_queue_notify_request(local_gpe_event_info->dispatch.
+                                                 device_node,
+                                                 ACPI_NOTIFY_DEVICE_WAKE);
+                break;
+
+        case ACPI_GPE_DISPATCH_METHOD:
 
                 /* Allocate the evaluation information block */
 
@@ -518,6 +533,11 @@ static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
                                         (local_gpe_event_info->dispatch.
                                          method_node)));
                 }
+
+                break;
+
+        default:
+                return_VOID;    /* Should never happen */
         }
 
         /* Defer enabling of GPE until all notify handlers are done */
@@ -531,6 +551,7 @@ static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
         return_VOID;
 }
 
+
 /*******************************************************************************
  *
  * FUNCTION:    acpi_ev_asynch_enable_gpe
@@ -541,38 +562,60 @@ static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
  * RETURN:      None
  *
  * DESCRIPTION: Asynchronous clear/enable for GPE. This allows the GPE to
- *              complete.
+ *              complete (i.e., finish execution of Notify)
  *
  ******************************************************************************/
 
 static void ACPI_SYSTEM_XFACE acpi_ev_asynch_enable_gpe(void *context)
 {
         struct acpi_gpe_event_info *gpe_event_info = context;
+
+        (void)acpi_ev_finish_gpe(gpe_event_info);
+
+        ACPI_FREE(gpe_event_info);
+        return;
+}
+
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ev_finish_gpe
+ *
+ * PARAMETERS:  gpe_event_info      - Info for this GPE
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Clear/Enable a GPE. Common code that is used after execution
+ *              of a GPE method or a synchronous or asynchronous GPE handler.
+ *
+ ******************************************************************************/
+
+acpi_status acpi_ev_finish_gpe(struct acpi_gpe_event_info *gpe_event_info)
+{
         acpi_status status;
 
         if ((gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK) ==
             ACPI_GPE_LEVEL_TRIGGERED) {
                 /*
-                 * GPE is level-triggered, we clear the GPE status bit after handling
-                 * the event.
+                 * GPE is level-triggered, we clear the GPE status bit after
+                 * handling the event.
                  */
                 status = acpi_hw_clear_gpe(gpe_event_info);
                 if (ACPI_FAILURE(status)) {
-                        goto exit;
+                        return (status);
                 }
         }
 
         /*
-         * Enable this GPE, conditionally. This means that the GPE will only be
-         * physically enabled if the enable_for_run bit is set in the event_info
+         * Enable this GPE, conditionally. This means that the GPE will
+         * only be physically enabled if the enable_for_run bit is set
+         * in the event_info.
          */
         (void)acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_CONDITIONAL_ENABLE);
-
-exit:
-        ACPI_FREE(gpe_event_info);
-        return;
+        return (AE_OK);
 }
 
+
 /*******************************************************************************
  *
  * FUNCTION:    acpi_ev_gpe_dispatch
@@ -595,6 +638,7 @@ acpi_ev_gpe_dispatch(struct acpi_namespace_node *gpe_device,
                     struct acpi_gpe_event_info *gpe_event_info, u32 gpe_number)
 {
         acpi_status status;
+        u32 return_value;
 
         ACPI_FUNCTION_TRACE(ev_gpe_dispatch);
 
@@ -616,54 +660,49 @@ acpi_ev_gpe_dispatch(struct acpi_namespace_node *gpe_device,
         }
 
         /*
-         * Dispatch the GPE to either an installed handler, or the control method
-         * associated with this GPE (_Lxx or _Exx). If a handler exists, we invoke
-         * it and do not attempt to run the method. If there is neither a handler
-         * nor a method, we disable this GPE to prevent further such pointless
-         * events from firing.
+         * Always disable the GPE so that it does not keep firing before
+         * any asynchronous activity completes (either from the execution
+         * of a GPE method or an asynchronous GPE handler.)
+         *
+         * If there is no handler or method to run, just disable the
+         * GPE and leave it disabled permanently to prevent further such
+         * pointless events from firing.
+         */
+        status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
+        if (ACPI_FAILURE(status)) {
+                ACPI_EXCEPTION((AE_INFO, status,
+                                "Unable to disable GPE%02X", gpe_number));
+                return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
+        }
+
+        /*
+         * Dispatch the GPE to either an installed handler or the control
+         * method associated with this GPE (_Lxx or _Exx). If a handler
+         * exists, we invoke it and do not attempt to run the method.
+         * If there is neither a handler nor a method, leave the GPE
+         * disabled.
          */
         switch (gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) {
         case ACPI_GPE_DISPATCH_HANDLER:
 
-                /*
-                 * Invoke the installed handler (at interrupt level)
-                 * Ignore return status for now.
-                 * TBD: leave GPE disabled on error?
-                 */
-                (void)gpe_event_info->dispatch.handler->address(gpe_device,
-                                                                gpe_number,
-                                                                gpe_event_info->
-                                                                dispatch.
-                                                                handler->
-                                                                context);
-
-                /* It is now safe to clear level-triggered events. */
-
-                if ((gpe_event_info->flags & ACPI_GPE_XRUPT_TYPE_MASK) ==
-                    ACPI_GPE_LEVEL_TRIGGERED) {
-                        status = acpi_hw_clear_gpe(gpe_event_info);
-                        if (ACPI_FAILURE(status)) {
-                                ACPI_EXCEPTION((AE_INFO, status,
-                                        "Unable to clear GPE[0x%2X]",
-                                                gpe_number));
-                                return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
-                        }
+                /* Invoke the installed handler (at interrupt level) */
+
+                return_value =
+                    gpe_event_info->dispatch.handler->address(gpe_device,
+                                                              gpe_number,
+                                                              gpe_event_info->
+                                                              dispatch.handler->
+                                                              context);
+
+                /* If requested, clear (if level-triggered) and reenable the GPE */
+
+                if (return_value & ACPI_REENABLE_GPE) {
+                        (void)acpi_ev_finish_gpe(gpe_event_info);
                 }
                 break;
 
         case ACPI_GPE_DISPATCH_METHOD:
-
-                /*
-                 * Disable the GPE, so it doesn't keep firing before the method has a
-                 * chance to run (it runs asynchronously with interrupts enabled).
-                 */
-                status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
-                if (ACPI_FAILURE(status)) {
-                        ACPI_EXCEPTION((AE_INFO, status,
-                                        "Unable to disable GPE[0x%2X]",
-                                        gpe_number));
-                        return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
-                }
+        case ACPI_GPE_DISPATCH_NOTIFY:
 
                 /*
                  * Execute the method associated with the GPE
@@ -690,17 +729,6 @@ acpi_ev_gpe_dispatch(struct acpi_namespace_node *gpe_device,
                             "No handler or method for GPE[0x%2X], disabling event",
                             gpe_number));
 
-                /*
-                 * Disable the GPE. The GPE will remain disabled a handler
-                 * is installed or ACPICA is restarted.
-                 */
-                status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
-                if (ACPI_FAILURE(status)) {
-                        ACPI_EXCEPTION((AE_INFO, status,
-                                        "Unable to disable GPE[0x%2X]",
-                                        gpe_number));
-                        return_UINT32(ACPI_INTERRUPT_NOT_HANDLED);
-                }
                 break;
         }
 
diff --git a/drivers/acpi/acpica/evgpeblk.c b/drivers/acpi/acpica/evgpeblk.c
index 2a445dfcfdb4..e2e8164bb811 100644
--- a/drivers/acpi/acpica/evgpeblk.c
+++ b/drivers/acpi/acpica/evgpeblk.c
@@ -472,9 +472,14 @@ acpi_ev_initialize_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
                         gpe_index = (i * ACPI_GPE_REGISTER_WIDTH) + j;
                         gpe_event_info = &gpe_block->event_info[gpe_index];
 
-                        /* Ignore GPEs that have no corresponding _Lxx/_Exx method */
-
-                        if (!(gpe_event_info->flags & ACPI_GPE_DISPATCH_METHOD)
+                        /*
+                         * Ignore GPEs that have no corresponding _Lxx/_Exx method
+                         * and GPEs that are used to wake the system
+                         */
+                        if (((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
+                             ACPI_GPE_DISPATCH_NONE)
+                            || ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK)
+                                == ACPI_GPE_DISPATCH_HANDLER)
                             || (gpe_event_info->flags & ACPI_GPE_CAN_WAKE)) {
                                 continue;
                         }
diff --git a/drivers/acpi/acpica/evgpeinit.c b/drivers/acpi/acpica/evgpeinit.c
index 4c8dea513b66..734a494bd705 100644
--- a/drivers/acpi/acpica/evgpeinit.c
+++ b/drivers/acpi/acpica/evgpeinit.c
@@ -415,6 +415,7 @@ acpi_ev_match_gpe_method(acpi_handle obj_handle,
          * Add the GPE information from above to the gpe_event_info block for
          * use during dispatch of this GPE.
          */
+        gpe_event_info->flags &= ~(ACPI_GPE_DISPATCH_MASK);
         gpe_event_info->flags |= (u8)(type | ACPI_GPE_DISPATCH_METHOD);
         gpe_event_info->dispatch.method_node = method_node;
 
diff --git a/drivers/acpi/acpica/evxfgpe.c b/drivers/acpi/acpica/evxfgpe.c
index 99f77ab29729..fcf4a5cdc9a4 100644
--- a/drivers/acpi/acpica/evxfgpe.c
+++ b/drivers/acpi/acpica/evxfgpe.c
@@ -166,39 +166,75 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number)
 }
 ACPI_EXPORT_SYMBOL(acpi_disable_gpe)
 
+
 /*******************************************************************************
  *
  * FUNCTION:    acpi_setup_gpe_for_wake
  *
- * PARAMETERS:  gpe_device      - Parent GPE Device. NULL for GPE0/GPE1
- *              gpe_number      - GPE level within the GPE block
+ * PARAMETERS:  wake_device         - Device associated with the GPE (via _PRW)
+ *              gpe_device          - Parent GPE Device. NULL for GPE0/GPE1
+ *              gpe_number          - GPE level within the GPE block
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Set the ACPI_GPE_CAN_WAKE flag for the given GPE.  If the GPE
- *              has a corresponding method and is currently enabled, disable it
- *              (GPEs with corresponding methods are enabled unconditionally
- *              during initialization, but GPEs that can wake up are expected
- *              to be initially disabled).
+ * DESCRIPTION: Mark a GPE as having the ability to wake the system. This
+ *              interface is intended to be used as the host executes the
+ *              _PRW methods (Power Resources for Wake) in the system tables.
+ *              Each _PRW appears under a Device Object (The wake_device), and
+ *              contains the info for the wake GPE associated with the
+ *              wake_device.
  *
  ******************************************************************************/
-acpi_status acpi_setup_gpe_for_wake(acpi_handle gpe_device, u32 gpe_number)
+acpi_status
+acpi_setup_gpe_for_wake(acpi_handle wake_device,
+                        acpi_handle gpe_device, u32 gpe_number)
 {
-        acpi_status status = AE_OK;
+        acpi_status status = AE_BAD_PARAMETER;
         struct acpi_gpe_event_info *gpe_event_info;
+        struct acpi_namespace_node *device_node;
         acpi_cpu_flags flags;
 
         ACPI_FUNCTION_TRACE(acpi_setup_gpe_for_wake);
 
+        /* Parameter Validation */
+
+        if (!wake_device) {
+                /*
+                 * By forcing wake_device to be valid, we automatically enable the
+                 * implicit notify feature on all hosts.
+                 */
+                return_ACPI_STATUS(AE_BAD_PARAMETER);
+        }
+
+        /* Validate wake_device is of type Device */
+
+        device_node = ACPI_CAST_PTR(struct acpi_namespace_node, wake_device);
+        if (device_node->type != ACPI_TYPE_DEVICE) {
+                return_ACPI_STATUS(AE_BAD_PARAMETER);
+        }
+
         flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
 
         /* Ensure that we have a valid GPE number */
 
         gpe_event_info = acpi_ev_get_gpe_event_info(gpe_device, gpe_number);
         if (gpe_event_info) {
+                /*
+                 * If there is no method or handler for this GPE, then the
+                 * wake_device will be notified whenever this GPE fires (aka
+                 * "implicit notify") Note: The GPE is assumed to be
+                 * level-triggered (for windows compatibility).
+                 */
+                if ((gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK) ==
+                    ACPI_GPE_DISPATCH_NONE) {
+                        gpe_event_info->flags =
+                            (ACPI_GPE_DISPATCH_NOTIFY |
+                             ACPI_GPE_LEVEL_TRIGGERED);
+                        gpe_event_info->dispatch.device_node = device_node;
+                }
+
                 gpe_event_info->flags |= ACPI_GPE_CAN_WAKE;
-        } else {
-                status = AE_BAD_PARAMETER;
+                status = AE_OK;
         }
 
         acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 81887724de80..fa848c4116a8 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -619,7 +619,7 @@ static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
                 wake_up(&ec->wait);
                 ec_check_sci(ec, acpi_ec_read_status(ec));
         }
-        return ACPI_INTERRUPT_HANDLED;
+        return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
 }
 
 /* --------------------------------------------------------------------------
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 70249b3d2934..ce6741ee1965 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -778,7 +778,7 @@ acpi_bus_extract_wakeup_device_power_package(acpi_handle handle,
                 wakeup->resources.handles[i] = element->reference.handle;
         }
 
-        acpi_setup_gpe_for_wake(wakeup->gpe_device, wakeup->gpe_number);
+        acpi_setup_gpe_for_wake(handle, wakeup->gpe_device, wakeup->gpe_number);
 
  out:
         kfree(buffer.pointer);