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, 18 insertions, 5 deletions

diff --git a/drivers/acpi/acpica/hwgpe.c b/drivers/acpi/acpica/hwgpe.c
index bdecd5e..76b0e35 100644
--- a/drivers/acpi/acpica/hwgpe.c
+++ b/drivers/acpi/acpica/hwgpe.c
@@ -98,7 +98,7 @@ acpi_status
 acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u32 action)
 {
 	struct acpi_gpe_register_info *gpe_register_info;
-	acpi_status status;
+	acpi_status status = AE_OK;
 	u32 enable_mask;
 	u32 register_bit;
 
@@ -148,9 +148,14 @@ acpi_hw_low_set_gpe(struct acpi_gpe_event_info *gpe_event_info, u32 action)
 		return (AE_BAD_PARAMETER);
 	}
 
-	/* Write the updated enable mask */
+	if (!(register_bit & gpe_register_info->mask_for_run)) {
 
-	status = acpi_hw_write(enable_mask, &gpe_register_info->enable_address);
+		/* Write the updated enable mask */
+
+		status =
+		    acpi_hw_write(enable_mask,
+				  &gpe_register_info->enable_address);
+	}
 	return (status);
 }
 
@@ -242,6 +247,12 @@ acpi_hw_get_gpe_status(struct acpi_gpe_event_info *gpe_event_info,
 		local_event_status |= ACPI_EVENT_FLAG_ENABLED;
 	}
 
+	/* GPE currently masked? (masked for runtime?) */
+
+	if (register_bit & gpe_register_info->mask_for_run) {
+		local_event_status |= ACPI_EVENT_FLAG_MASKED;
+	}
+
 	/* GPE enabled for wake? */
 
 	if (register_bit & gpe_register_info->enable_for_wake) {
@@ -397,6 +408,7 @@ acpi_hw_enable_runtime_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
 	u32 i;
 	acpi_status status;
 	struct acpi_gpe_register_info *gpe_register_info;
+	u8 enable_mask;
 
 	/* NOTE: assumes that all GPEs are currently disabled */
 
@@ -410,9 +422,10 @@ acpi_hw_enable_runtime_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
 
 		/* Enable all "runtime" GPEs in this register */
 
+		enable_mask = gpe_register_info->enable_for_run &
+		    ~gpe_register_info->mask_for_run;
 		status =
-		    acpi_hw_gpe_enable_write(gpe_register_info->enable_for_run,
-					     gpe_register_info);
+		    acpi_hw_gpe_enable_write(enable_mask, gpe_register_info);
 		if (ACPI_FAILURE(status)) {
 			return (status);
 		}