ACPICA: Events: Introduce acpi_mask_gpe() to implement GPE masking mechanism

ACPICA commit 23a417ca406a527e7ae1710893e59a8b6db30e14

There is a facility in Linux, developers can control the enabling/disabling
of a GPE via /sys/firmware/acpi/interrupts/gpexx. This is mainly for
debugging purposes.

But many users expect to use this facility to implement quirks to mask a
specific GPE when there is a gap in Linux causing this GPE to flood. This
is not working correctly because currently this facility invokes
enabling/disabling counting based GPE driver APIs:
 acpi_enable_gpe()/acpi_disable_gpe()
and the GPE drivers can still affect the count to mess up the GPE
masking purposes.

However, most of the IRQ chip designs allow masking/unmasking IRQs via a
masking bit which is different from the enabled bit to achieve the same
purpose. But the GPE hardware doesn't contain such a feature, this brings
the trouble.

In this patch, we introduce a software mechanism to implement the GPE
masking feature, and acpi_mask_gpe() are provided to the OSPMs to
mask/unmask GPEs in the above mentioned situation instead of
acpi_enable_gpe()/acpi_disable_gpe(). ACPICA BZ 1102. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/23a417ca
Link: https://bugs.acpica.org/show_bug.cgi?id=1102
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/drivers/acpi/acpica/evgpe.c b/drivers/acpi/acpica/evgpe.c
index 4b4949ce05bc..bdb10bee13ce 100644
--- a/drivers/acpi/acpica/evgpe.c
+++ b/drivers/acpi/acpica/evgpe.c
@@ -130,6 +130,60 @@ acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info)
 
 /*******************************************************************************
  *
+ * FUNCTION:    acpi_ev_mask_gpe
+ *
+ * PARAMETERS:  gpe_event_info          - GPE to be blocked/unblocked
+ *              is_masked               - Whether the GPE is masked or not
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Unconditionally mask/unmask a GPE during runtime.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ev_mask_gpe(struct acpi_gpe_event_info *gpe_event_info, u8 is_masked)
+{
+	struct acpi_gpe_register_info *gpe_register_info;
+	u32 register_bit;
+
+	ACPI_FUNCTION_TRACE(ev_mask_gpe);
+
+	gpe_register_info = gpe_event_info->register_info;
+	if (!gpe_register_info) {
+		return_ACPI_STATUS(AE_NOT_EXIST);
+	}
+
+	register_bit = acpi_hw_get_gpe_register_bit(gpe_event_info);
+
+	/* Perform the action */
+
+	if (is_masked) {
+		if (register_bit & gpe_register_info->mask_for_run) {
+			return_ACPI_STATUS(AE_BAD_PARAMETER);
+		}
+
+		(void)acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_DISABLE);
+		ACPI_SET_BIT(gpe_register_info->mask_for_run, (u8)register_bit);
+	} else {
+		if (!(register_bit & gpe_register_info->mask_for_run)) {
+			return_ACPI_STATUS(AE_BAD_PARAMETER);
+		}
+
+		ACPI_CLEAR_BIT(gpe_register_info->mask_for_run,
+			       (u8)register_bit);
+		if (gpe_event_info->runtime_count
+		    && !gpe_event_info->disable_for_dispatch) {
+			(void)acpi_hw_low_set_gpe(gpe_event_info,
+						  ACPI_GPE_ENABLE);
+		}
+	}
+
+	return_ACPI_STATUS(AE_OK);
+}
+
+/*******************************************************************************
+ *
  * FUNCTION:    acpi_ev_add_gpe_reference
  *
  * PARAMETERS:  gpe_event_info          - Add a reference to this GPE
@@ -674,6 +728,7 @@ acpi_status acpi_ev_finish_gpe(struct acpi_gpe_event_info *gpe_event_info)
 	 * in the event_info.
 	 */
 	(void)acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_CONDITIONAL_ENABLE);
+	gpe_event_info->disable_for_dispatch = FALSE;
 	return (AE_OK);
 }
 
@@ -737,6 +792,8 @@ acpi_ev_gpe_dispatch(struct acpi_namespace_node *gpe_device,
 		}
 	}
 
+	gpe_event_info->disable_for_dispatch = TRUE;
+
 	/*
 	 * Dispatch the GPE to either an installed handler or the control
 	 * method associated with this GPE (_Lxx or _Exx). If a handler