ACPI: Use GPE reference counting to support shared GPEs

ACPI GPEs may map to multiple devices.  The current GPE interface
only provides a mechanism for enabling and disabling GPEs, making
it difficult to change the state of GPEs at runtime without extensive
cooperation between devices.

Add an API to allow devices to indicate whether or not they want
their device's GPE to be enabled for both runtime and wakeup events.

Remove the old GPE type handling entirely, which gets rid of various
quirks, like the implicit disabling with GPE type setting. This
requires a small amount of rework in order to ensure that non-wake
GPEs are enabled by default to preserve existing behaviour.

Based on patches from Matthew Garrett <mjg@redhat.com>.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 65 insertions, 25 deletions

diff --git a/drivers/acpi/acpica/evxfevnt.c b/drivers/acpi/acpica/evxfevnt.c
index eed7a38d25f2..1aea1a734159 100644
--- a/drivers/acpi/acpica/evxfevnt.c
+++ b/drivers/acpi/acpica/evxfevnt.c
@@ -201,23 +201,27 @@ ACPI_EXPORT_SYMBOL(acpi_enable_event)
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_set_gpe_type
+ * FUNCTION:    acpi_set_gpe
  *
  * PARAMETERS:  gpe_device      - Parent GPE Device
  *              gpe_number      - GPE level within the GPE block
- *              Type            - New GPE type
+ *              action          - Enable or disable
+ *                                Called from ISR or not
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Set the type of an individual GPE
+ * DESCRIPTION: Enable or disable an ACPI event (general purpose)
  *
  ******************************************************************************/
-acpi_status acpi_set_gpe_type(acpi_handle gpe_device, u32 gpe_number, u8 type)
+acpi_status acpi_set_gpe(acpi_handle gpe_device, u32 gpe_number, u8 action)
 {
         acpi_status status = AE_OK;
+        acpi_cpu_flags flags;
         struct acpi_gpe_event_info *gpe_event_info;
 
-        ACPI_FUNCTION_TRACE(acpi_set_gpe_type);
+        ACPI_FUNCTION_TRACE(acpi_set_gpe);
+
+        flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
 
         /* Ensure that we have a valid GPE number */
 
@@ -227,19 +231,29 @@ acpi_status acpi_set_gpe_type(acpi_handle gpe_device, u32 gpe_number, u8 type)
                 goto unlock_and_exit;
         }
 
-        if ((gpe_event_info->flags & ACPI_GPE_TYPE_MASK) == type) {
-                return_ACPI_STATUS(AE_OK);
-        }
+        /* Perform the action */
+
+        switch (action) {
+        case ACPI_GPE_ENABLE:
+                status = acpi_ev_enable_gpe(gpe_event_info, TRUE);
+                break;
 
-        /* Set the new type (will disable GPE if currently enabled) */
+        case ACPI_GPE_DISABLE:
+                status = acpi_ev_disable_gpe(gpe_event_info);
+                break;
 
-        status = acpi_ev_set_gpe_type(gpe_event_info, type);
+        default:
+                ACPI_ERROR((AE_INFO, "Invalid action\n"));
+                status = AE_BAD_PARAMETER;
+                break;
+        }
 
       unlock_and_exit:
+        acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
         return_ACPI_STATUS(status);
 }
 
-ACPI_EXPORT_SYMBOL(acpi_set_gpe_type)
+ACPI_EXPORT_SYMBOL(acpi_set_gpe)
 
 /*******************************************************************************
  *
@@ -247,15 +261,14 @@ ACPI_EXPORT_SYMBOL(acpi_set_gpe_type)
  *
  * PARAMETERS:  gpe_device      - Parent GPE Device
  *              gpe_number      - GPE level within the GPE block
- *              Flags           - Just enable, or also wake enable?
- *                                Called from ISR or not
+ *              type            - Purpose the GPE will be used for
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Enable an ACPI event (general purpose)
+ * DESCRIPTION: Take a reference to a GPE and enable it if necessary
  *
  ******************************************************************************/
-acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number)
+acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 type)
 {
         acpi_status status = AE_OK;
         acpi_cpu_flags flags;
@@ -273,15 +286,32 @@ acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number)
                 goto unlock_and_exit;
         }
 
-        /* Perform the enable */
+        if (type & ACPI_GPE_TYPE_RUNTIME) {
+                if (++gpe_event_info->runtime_count == 1)
+                        status = acpi_ev_enable_gpe(gpe_event_info, TRUE);
 
-        status = acpi_ev_enable_gpe(gpe_event_info, TRUE);
+                if (ACPI_FAILURE(status))
+                        gpe_event_info->runtime_count--;
+        }
 
-      unlock_and_exit:
+        if (type & ACPI_GPE_TYPE_WAKE) {
+                if (!(gpe_event_info->flags & ACPI_GPE_CAN_WAKE)) {
+                        status = AE_BAD_PARAMETER;
+                        goto unlock_and_exit;
+                }
+
+                /*
+                 * Wake-up GPEs are only enabled right prior to putting the
+                 * system into a sleep state.
+                 */
+                if (++gpe_event_info->wakeup_count == 1)
+                        acpi_ev_update_gpe_enable_masks(gpe_event_info);
+        }
+
+unlock_and_exit:
         acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
         return_ACPI_STATUS(status);
 }
-
 ACPI_EXPORT_SYMBOL(acpi_enable_gpe)
 
 /*******************************************************************************
@@ -290,15 +320,14 @@ ACPI_EXPORT_SYMBOL(acpi_enable_gpe)
  *
  * PARAMETERS:  gpe_device      - Parent GPE Device
  *              gpe_number      - GPE level within the GPE block
- *              Flags           - Just disable, or also wake disable?
- *                                Called from ISR or not
+ *              type            - Purpose the GPE won't be used for any more
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Disable an ACPI event (general purpose)
+ * DESCRIPTION: Release a reference to a GPE and disable it if necessary
  *
  ******************************************************************************/
-acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number)
+acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 type)
 {
         acpi_status status = AE_OK;
         acpi_cpu_flags flags;
@@ -315,13 +344,24 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number)
                 goto unlock_and_exit;
         }
 
-        status = acpi_ev_disable_gpe(gpe_event_info);
+        if ((type & ACPI_GPE_TYPE_WAKE) && gpe_event_info->runtime_count) {
+                if (--gpe_event_info->runtime_count == 0)
+                        acpi_ev_disable_gpe(gpe_event_info);
+        }
+
+        if ((type & ACPI_GPE_TYPE_RUNTIME) && gpe_event_info->wakeup_count) {
+                /*
+                 * Wake-up GPEs are not enabled after leaving system sleep
+                 * states, so we don't need to disable them here.
+                 */
+                if (--gpe_event_info->wakeup_count == 0)
+                        acpi_ev_update_gpe_enable_masks(gpe_event_info);
+        }
 
 unlock_and_exit:
         acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
         return_ACPI_STATUS(status);
 }
-
 ACPI_EXPORT_SYMBOL(acpi_disable_gpe)
 
 /*******************************************************************************