ACPICA: Update to GPIO region handler interface.

Changes to correct several GPIO issues:

1) The update_rule in a GPIO field definition is now ignored;
a read-modify-write operation is never performed for GPIO fields.
(Internally, this means that the field assembly/disassembly
code is completely bypassed for GPIO.)

2) The Address parameter passed to a GPIO region handler is
now the bit offset of the field from a previous Connection()
operator. Thus, it becomes a "Pin Number Index" into the
Connection() resource descriptor.

3) The bit_width parameter passed to a GPIO region handler is
now the exact bit width of the GPIO field. Thus, it can be
interpreted as "number of pins".

Overall, we can now say that the region handler interface
to GPIO handlers is a raw "bit/pin" addressed interface, not
a byte-addressed interface like the system_memory handler interface.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: 3.15+ <stable@vger.kernel.org> # 3.15+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 31 insertions, 16 deletions

diff --git a/drivers/acpi/acpica/evregion.c b/drivers/acpi/acpica/evregion.c
index 9957297..8eb8575 100644
--- a/drivers/acpi/acpica/evregion.c
+++ b/drivers/acpi/acpica/evregion.c
@@ -142,6 +142,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
 	union acpi_operand_object *region_obj2;
 	void *region_context = NULL;
 	struct acpi_connection_info *context;
+	acpi_physical_address address;
 
 	ACPI_FUNCTION_TRACE(ev_address_space_dispatch);
 
@@ -231,25 +232,23 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
 	/* We have everything we need, we can invoke the address space handler */
 
 	handler = handler_desc->address_space.handler;
-
-	ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
-			  "Handler %p (@%p) Address %8.8X%8.8X [%s]\n",
-			  &region_obj->region.handler->address_space, handler,
-			  ACPI_FORMAT_NATIVE_UINT(region_obj->region.address +
-						  region_offset),
-			  acpi_ut_get_region_name(region_obj->region.
-						  space_id)));
+	address = (region_obj->region.address + region_offset);
 
 	/*
 	 * Special handling for generic_serial_bus and general_purpose_io:
 	 * There are three extra parameters that must be passed to the
 	 * handler via the context:
-	 *   1) Connection buffer, a resource template from Connection() op.
-	 *   2) Length of the above buffer.
-	 *   3) Actual access length from the access_as() op.
+	 *   1) Connection buffer, a resource template from Connection() op
+	 *   2) Length of the above buffer
+	 *   3) Actual access length from the access_as() op
+	 *
+	 * In addition, for general_purpose_io, the Address and bit_width fields
+	 * are defined as follows:
+	 *   1) Address is the pin number index of the field (bit offset from
+	 *      the previous Connection)
+	 *   2) bit_width is the actual bit length of the field (number of pins)
 	 */
-	if (((region_obj->region.space_id == ACPI_ADR_SPACE_GSBUS) ||
-	     (region_obj->region.space_id == ACPI_ADR_SPACE_GPIO)) &&
+	if ((region_obj->region.space_id == ACPI_ADR_SPACE_GSBUS) &&
 	    context && field_obj) {
 
 		/* Get the Connection (resource_template) buffer */
@@ -258,6 +257,24 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
 		context->length = field_obj->field.resource_length;
 		context->access_length = field_obj->field.access_length;
 	}
+	if ((region_obj->region.space_id == ACPI_ADR_SPACE_GPIO) &&
+	    context && field_obj) {
+
+		/* Get the Connection (resource_template) buffer */
+
+		context->connection = field_obj->field.resource_buffer;
+		context->length = field_obj->field.resource_length;
+		context->access_length = field_obj->field.access_length;
+		address = field_obj->field.pin_number_index;
+		bit_width = field_obj->field.bit_length;
+	}
+
+	ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
+			  "Handler %p (@%p) Address %8.8X%8.8X [%s]\n",
+			  &region_obj->region.handler->address_space, handler,
+			  ACPI_FORMAT_NATIVE_UINT(address),
+			  acpi_ut_get_region_name(region_obj->region.
+						  space_id)));
 
 	if (!(handler_desc->address_space.handler_flags &
 	      ACPI_ADDR_HANDLER_DEFAULT_INSTALLED)) {
@@ -271,9 +288,7 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
 
 	/* Call the handler */
 
-	status = handler(function,
-			 (region_obj->region.address + region_offset),
-			 bit_width, value, context,
+	status = handler(function, address, bit_width, value, context,
 			 region_obj2->extra.region_context);
 
 	if (ACPI_FAILURE(status)) {