ACPI / ACPICA: Fix low-level GPE manipulation code

ACPICA uses acpi_ev_enable_gpe() for enabling GPEs at the low level,
which is incorrect, because this function only enables the GPE if the
corresponding bit in its enable register's enable_for_run mask is set.
This causes acpi_set_gpe() to work incorrectly if used for enabling
GPEs that were not previously enabled with acpi_enable_gpe().  As a
result, among other things, wakeup-only GPEs are never enabled by
acpi_enable_wakeup_device(), so the devices that use them are unable
to wake up the system.

To fix this issue remove acpi_ev_enable_gpe() and its counterpart
acpi_ev_disable_gpe() and replace acpi_hw_low_disable_gpe() with
acpi_hw_low_set_gpe() that will be used instead to manipulate GPE
enable bits at the low level.  Make the users of acpi_ev_enable_gpe()
and acpi_ev_disable_gpe() call acpi_hw_low_set_gpe() instead and
make sure that GPE enable masks are only updated by acpi_enable_gpe()
and acpi_disable_gpe() when GPE reference counters change from 0
to 1 and from 1 to 0, respectively.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

5 files changed, 78 insertions, 122 deletions

diff --git a/drivers/acpi/acpica/acevents.h b/drivers/acpi/acpica/acevents.h
index 5e094a28cf54..138bbb521930 100644
--- a/drivers/acpi/acpica/acevents.h
+++ b/drivers/acpi/acpica/acevents.h
@@ -78,10 +78,6 @@ 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);
-
-acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info);
-
 struct acpi_gpe_event_info *acpi_ev_get_gpe_event_info(acpi_handle gpe_device,
 						       u32 gpe_number);
 
diff --git a/drivers/acpi/acpica/achware.h b/drivers/acpi/acpica/achware.h
index c46277d179f0..32391588e163 100644
--- a/drivers/acpi/acpica/achware.h
+++ b/drivers/acpi/acpica/achware.h
@@ -93,7 +93,8 @@ acpi_status acpi_hw_write_port(acpi_io_address address, u32 value, u32 width);
 u32 acpi_hw_gpe_register_bit(struct acpi_gpe_event_info *gpe_event_info,
 			     struct acpi_gpe_register_info *gpe_register_info);
 
-acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info);
+acpi_status
+acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u8 action);
 
 acpi_status
 acpi_hw_write_gpe_enable_reg(struct acpi_gpe_event_info *gpe_event_info);
diff --git a/drivers/acpi/acpica/evgpe.c b/drivers/acpi/acpica/evgpe.c
index 57eeb3bde41e..66cd03835d6e 100644
--- a/drivers/acpi/acpica/evgpe.c
+++ b/drivers/acpi/acpica/evgpe.c
@@ -99,106 +99,6 @@ acpi_ev_update_gpe_enable_masks(struct acpi_gpe_event_info *gpe_event_info)
 	return_ACPI_STATUS(AE_OK);
 }
 
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ev_enable_gpe
- *
- * PARAMETERS:  gpe_event_info          - GPE to enable
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Hardware-enable a GPE. Always enables the GPE, regardless
- *              of type or number of references.
- *
- * Note: The GPE lock should be already acquired when this function is called.
- *
- ******************************************************************************/
-
-acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
-{
-	acpi_status status;
-
-
-	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.
-	 */
-	if (!(gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK)) {
-		return_ACPI_STATUS(AE_NO_HANDLER);
-	}
-
-	/* Ensure the HW enable masks are current */
-
-	status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
-	if (ACPI_FAILURE(status)) {
-		return_ACPI_STATUS(status);
-	}
-
-	/* Clear the GPE (of stale events) */
-
-	status = acpi_hw_clear_gpe(gpe_event_info);
-	if (ACPI_FAILURE(status)) {
-		return_ACPI_STATUS(status);
-	}
-
-	/* Enable the requested GPE */
-
-	status = acpi_hw_write_gpe_enable_reg(gpe_event_info);
-	return_ACPI_STATUS(status);
-}
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ev_disable_gpe
- *
- * PARAMETERS:  gpe_event_info          - GPE to disable
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Hardware-disable a GPE. Always disables the requested GPE,
- *              regardless of the type or number of references.
- *
- * Note: The GPE lock should be already acquired when this function is called.
- *
- ******************************************************************************/
-
-acpi_status acpi_ev_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
-{
-	acpi_status status;
-
-	ACPI_FUNCTION_TRACE(ev_disable_gpe);
-
-
-	/*
-	 * Note: Always disable the GPE, even if we think that that it is already
-	 * disabled. It is possible that the AML or some other code has enabled
-	 * the GPE behind our back.
-	 */
-
-	/* Ensure the HW enable masks are current */
-
-	status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
-	if (ACPI_FAILURE(status)) {
-		return_ACPI_STATUS(status);
-	}
-
-	/*
-	 * Always H/W disable this GPE, even if we don't know the GPE type.
-	 * Simply clear the enable bit for this particular GPE, but do not
-	 * write out the current GPE enable mask since this may inadvertently
-	 * enable GPEs too early. An example is a rogue GPE that has arrived
-	 * during ACPICA initialization - possibly because AML or other code
-	 * has enabled the GPE.
-	 */
-	status = acpi_hw_low_disable_gpe(gpe_event_info);
-	return_ACPI_STATUS(status);
-}
-
 
 /*******************************************************************************
  *
@@ -450,10 +350,6 @@ static void ACPI_SYSTEM_XFACE acpi_ev_asynch_execute_gpe_method(void *context)
 		return_VOID;
 	}
 
-	/* Update the GPE register masks for return to enabled state */
-
-	(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
 	 * prevent a race condition with remove_handler/remove_block.
@@ -606,7 +502,7 @@ acpi_ev_gpe_dispatch(struct acpi_gpe_event_info *gpe_event_info, u32 gpe_number)
 		 * 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_ev_disable_gpe(gpe_event_info);
+		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]",
@@ -643,7 +539,7 @@ acpi_ev_gpe_dispatch(struct acpi_gpe_event_info *gpe_event_info, u32 gpe_number)
 		 * Disable the GPE. The GPE will remain disabled a handler
 		 * is installed or ACPICA is restarted.
 		 */
-		status = acpi_ev_disable_gpe(gpe_event_info);
+		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]",
diff --git a/drivers/acpi/acpica/evxfevnt.c b/drivers/acpi/acpica/evxfevnt.c
index 7c7bbb4d402c..e3d9f5c8e53d 100644
--- a/drivers/acpi/acpica/evxfevnt.c
+++ b/drivers/acpi/acpica/evxfevnt.c
@@ -201,6 +201,44 @@ ACPI_EXPORT_SYMBOL(acpi_enable_event)
 
 /*******************************************************************************
  *
+ * FUNCTION:    acpi_clear_and_enable_gpe
+ *
+ * PARAMETERS:  gpe_event_info  - GPE to enable
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Clear the given GPE from stale events and enable it.
+ *
+ ******************************************************************************/
+static acpi_status
+acpi_clear_and_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
+{
+	acpi_status status;
+
+	/*
+	 * 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.
+	 */
+	if (!(gpe_event_info->flags & ACPI_GPE_DISPATCH_MASK)) {
+		return_ACPI_STATUS(AE_NO_HANDLER);
+	}
+
+	/* Clear the GPE (of stale events) */
+	status = acpi_hw_clear_gpe(gpe_event_info);
+	if (ACPI_FAILURE(status)) {
+		return_ACPI_STATUS(status);
+	}
+
+	/* Enable the requested GPE */
+	status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_ENABLE);
+
+	return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
  * FUNCTION:    acpi_set_gpe
  *
  * PARAMETERS:  gpe_device      - Parent GPE Device. NULL for GPE0/GPE1
@@ -240,11 +278,11 @@ 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);
+		status = acpi_clear_and_enable_gpe(gpe_event_info);
 		break;
 
 	case ACPI_GPE_DISABLE:
-		status = acpi_ev_disable_gpe(gpe_event_info);
+		status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
 		break;
 
 	default:
@@ -307,7 +345,11 @@ acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type)
 
 		gpe_event_info->runtime_count++;
 		if (gpe_event_info->runtime_count == 1) {
-			status = acpi_ev_enable_gpe(gpe_event_info);
+			status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
+			if (ACPI_SUCCESS(status)) {
+				status = acpi_clear_and_enable_gpe(gpe_event_info);
+			}
+
 			if (ACPI_FAILURE(status)) {
 				gpe_event_info->runtime_count--;
 				goto unlock_and_exit;
@@ -334,7 +376,7 @@ acpi_status acpi_enable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type)
 		 */
 		gpe_event_info->wakeup_count++;
 		if (gpe_event_info->wakeup_count == 1) {
-			(void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
+			status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
 		}
 	}
 
@@ -394,7 +436,12 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type
 
 		gpe_event_info->runtime_count--;
 		if (!gpe_event_info->runtime_count) {
-			status = acpi_ev_disable_gpe(gpe_event_info);
+			status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
+			if (ACPI_SUCCESS(status)) {
+				status = acpi_hw_low_set_gpe(gpe_event_info,
+							     ACPI_GPE_DISABLE);
+			}
+
 			if (ACPI_FAILURE(status)) {
 				gpe_event_info->runtime_count++;
 				goto unlock_and_exit;
@@ -415,7 +462,7 @@ acpi_status acpi_disable_gpe(acpi_handle gpe_device, u32 gpe_number, u8 gpe_type
 
 		gpe_event_info->wakeup_count--;
 		if (!gpe_event_info->wakeup_count) {
-			(void)acpi_ev_update_gpe_enable_masks(gpe_event_info);
+			status = acpi_ev_update_gpe_enable_masks(gpe_event_info);
 		}
 	}
 
diff --git a/drivers/acpi/acpica/hwgpe.c b/drivers/acpi/acpica/hwgpe.c
index d989b8e786cc..40388e23e103 100644
--- a/drivers/acpi/acpica/hwgpe.c
+++ b/drivers/acpi/acpica/hwgpe.c
@@ -78,23 +78,27 @@ u32 acpi_hw_gpe_register_bit(struct acpi_gpe_event_info *gpe_event_info,
 
 /******************************************************************************
  *
- * FUNCTION:	acpi_hw_low_disable_gpe
+ * FUNCTION:	acpi_hw_low_set_gpe
  *
  * PARAMETERS:	gpe_event_info	    - Info block for the GPE to be disabled
+ *		action		    - Enable or disable
  *
  * RETURN:	Status
  *
- * DESCRIPTION: Disable a single GPE in the enable register.
+ * DESCRIPTION: Enable or disable a single GPE in its enable register.
  *
  ******************************************************************************/
 
-acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
+acpi_status
+acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u8 action)
 {
 	struct acpi_gpe_register_info *gpe_register_info;
 	acpi_status status;
 	u32 enable_mask;
 	u32 register_bit;
 
+	ACPI_FUNCTION_ENTRY();
+
 	/* Get the info block for the entire GPE register */
 
 	gpe_register_info = gpe_event_info->register_info;
@@ -109,11 +113,23 @@ acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
 		return (status);
 	}
 
-	/* Clear just the bit that corresponds to this GPE */
+	/* Set ot clear just the bit that corresponds to this GPE */
 
 	register_bit = acpi_hw_gpe_register_bit(gpe_event_info,
 						gpe_register_info);
-	ACPI_CLEAR_BIT(enable_mask, register_bit);
+	switch (action) {
+	case ACPI_GPE_ENABLE:
+		ACPI_SET_BIT(enable_mask, register_bit);
+		break;
+
+	case ACPI_GPE_DISABLE:
+		ACPI_CLEAR_BIT(enable_mask, register_bit);
+		break;
+
+	default:
+		ACPI_ERROR((AE_INFO, "Invalid action\n"));
+		return (AE_BAD_PARAMETER);
+	}
 
 	/* Write the updated enable mask */