ACPI: Use GPE reference counting to support shared GPEs

To fix a bug and address the reviewers' comments regarding the ACPI
GPE refcounting patch, do the following additional changes:

o Remove the second argument of acpi_ev_enable_gpe(),
  'write_to_hardware', because it is not necessary any more.

o Add the "bad parameter" test against 'type' in
  acpi_enable_gpe() and acpi_disable_gpe().

o Make acpi_enable_gpe() only check 'status' for runtime GPEs if
  acpi_ev_enable_gpe() was actually called.

o Make acpi_disable_gpe() return 'status' returned by
  acpi_ev_disable_gpe() and fix a bug where ACPI_GPE_TYPE_WAKE
  and ACPI_GPE_TYPE_RUNTIME were exchanged by mistake.

o Add comments explaining why acpi_set_gpe() is used by the ACPI EC
  driver.

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

4 files changed, 30 insertions, 22 deletions

diff --git a/drivers/acpi/acpica/acevents.h b/drivers/acpi/acpica/acevents.h
index 197aa4f39640..4ced54f7a5d9 100644
--- a/drivers/acpi/acpica/acevents.h
+++ b/drivers/acpi/acpica/acevents.h
@@ -78,9 +78,7 @@ acpi_ev_queue_notify_request(struct acpi_namespace_node *node,
 acpi_status
 acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info);
 
-acpi_status
-acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info,
-                   u8 write_to_hardware);
+acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info);
 
 acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info);
 
diff --git a/drivers/acpi/acpica/evgpe.c b/drivers/acpi/acpica/evgpe.c
index 30ca3a30ef00..0b453467a5a0 100644
--- a/drivers/acpi/acpica/evgpe.c
+++ b/drivers/acpi/acpica/evgpe.c
@@ -98,8 +98,6 @@ acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info)
  * FUNCTION:    acpi_ev_enable_gpe
  *
  * PARAMETERS:  gpe_event_info          - GPE to enable
- *              write_to_hardware       - Enable now, or just mark data structs
- *                                        (WAKE GPEs should be deferred)
  *
  * RETURN:      Status
  *
@@ -107,9 +105,7 @@ acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info)
  *
  ******************************************************************************/
 
-acpi_status
-acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info,
-                   u8 write_to_hardware)
+acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
 {
         acpi_status status;
 
@@ -123,7 +119,7 @@ acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info,
 
         /* Mark wake-enabled or HW enable, or both */
 
-        if (gpe_event_info->runtime_count && write_to_hardware) {
+        if (gpe_event_info->runtime_count) {
                 /* Clear the GPE (of stale events), then enable it */
                 status = acpi_hw_clear_gpe(gpe_event_info);
                 if (ACPI_FAILURE(status))
@@ -400,7 +396,7 @@ static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
 
         /* Set the GPE flags for return to enabled state */
 
-        (void)acpi_ev_enable_gpe(gpe_event_info, FALSE);
+        (void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
 
         /*
          * Take a snapshot of the GPE info for this level - we copy the info to
diff --git a/drivers/acpi/acpica/evxfevnt.c b/drivers/acpi/acpica/evxfevnt.c
index 1aea1a734159..124c157215bf 100644
--- a/drivers/acpi/acpica/evxfevnt.c
+++ b/drivers/acpi/acpica/evxfevnt.c
@@ -235,7 +235,7 @@ acpi_status acpi_set_gpe(acpi_handle gpe_device, u32 gpe_number, u8 action)
 
         switch (action) {
         case ACPI_GPE_ENABLE:
-                status = acpi_ev_enable_gpe(gpe_event_info, TRUE);
+                status = acpi_ev_enable_gpe(gpe_event_info);
                 break;
 
         case ACPI_GPE_DISABLE:
@@ -276,6 +276,9 @@ acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 type)
 
         ACPI_FUNCTION_TRACE(acpi_enable_gpe);
 
+        if (type & ~ACPI_GPE_TYPE_WAKE_RUN)
+                return_ACPI_STATUS(AE_BAD_PARAMETER);
+
         flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
 
         /* Ensure that we have a valid GPE number */
@@ -287,11 +290,11 @@ acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 type)
         }
 
         if (type & ACPI_GPE_TYPE_RUNTIME) {
-                if (++gpe_event_info->runtime_count == 1)
-                        status = acpi_ev_enable_gpe(gpe_event_info, TRUE);
-
-                if (ACPI_FAILURE(status))
-                        gpe_event_info->runtime_count--;
+                if (++gpe_event_info->runtime_count == 1) {
+                        status = acpi_ev_enable_gpe(gpe_event_info);
+                        if (ACPI_FAILURE(status))
+                                gpe_event_info->runtime_count--;
+                }
         }
 
         if (type & ACPI_GPE_TYPE_WAKE) {
@@ -335,6 +338,9 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 type)
 
         ACPI_FUNCTION_TRACE(acpi_disable_gpe);
 
+        if (type & ~ACPI_GPE_TYPE_WAKE_RUN)
+                return_ACPI_STATUS(AE_BAD_PARAMETER);
+
         flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
         /* Ensure that we have a valid GPE number */
 
@@ -344,12 +350,12 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 type)
                 goto unlock_and_exit;
         }
 
-        if ((type & ACPI_GPE_TYPE_WAKE) && gpe_event_info->runtime_count) {
+        if ((type & ACPI_GPE_TYPE_RUNTIME) && gpe_event_info->runtime_count) {
                 if (--gpe_event_info->runtime_count == 0)
-                        acpi_ev_disable_gpe(gpe_event_info);
+                        status = acpi_ev_disable_gpe(gpe_event_info);
         }
 
-        if ((type & ACPI_GPE_TYPE_RUNTIME) && gpe_event_info->wakeup_count) {
+        if ((type & ACPI_GPE_TYPE_WAKE) && 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.
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 0fa65a8210da..27e0b92b2e39 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -307,6 +307,10 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
         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 at the hardware level regardless of the
+                 * GPE reference counting, so that it doesn't trigger.
+                 */
                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
         }
 
@@ -316,7 +320,11 @@ static int acpi_ec_transaction(struct acpi_ec *ec, struct transaction *t)
         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 GPE outside of transaction */
+                /*
+                 * It is safe to enable the GPE outside of the transaction.  Use
+                 * acpi_set_gpe() for that, since we used it to disable the GPE
+                 * above.
+                 */
                 acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
         } else if (t->irq_count > ACPI_EC_STORM_THRESHOLD) {
                 pr_info(PREFIX "GPE storm detected, "
@@ -1059,7 +1067,7 @@ error:
 static int acpi_ec_suspend(struct acpi_device *device, pm_message_t state)
 {
         struct acpi_ec *ec = acpi_driver_data(device);
-        /* Stop using GPE */
+        /* Stop using the GPE, but keep it reference counted. */
         acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_DISABLE);
         return 0;
 }
@@ -1067,7 +1075,7 @@ static int acpi_ec_suspend(struct acpi_device *device, pm_message_t state)
 static int acpi_ec_resume(struct acpi_device *device)
 {
         struct acpi_ec *ec = acpi_driver_data(device);
-        /* Enable use of GPE back */
+        /* Enable the GPE again, but don't reference count it once more. */
         acpi_set_gpe(NULL, ec->gpe, ACPI_GPE_ENABLE);
         return 0;
 }