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>

drivers/acpi/acpica/acevents.h

@@ -85,6 +85,9 @@ acpi_ev_update_gpe_enable_mask(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_mask_gpe(struct acpi_gpe_event_info *gpe_event_info, u8 is_masked);
+
 acpi_status
 acpi_ev_add_gpe_reference(struct acpi_gpe_event_info *gpe_event_info);