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>

6 files changed, 104 insertions, 16 deletions

diff --git a/drivers/acpi/acpica/aclocal.h b/drivers/acpi/acpica/aclocal.h
index 1f9aba5fb81f..2747279fbe3c 100644
--- a/drivers/acpi/acpica/aclocal.h
+++ b/drivers/acpi/acpica/aclocal.h
@@ -254,6 +254,7 @@ struct acpi_create_field_info {
         u32 field_bit_position;
         u32 field_bit_length;
         u16 resource_length;
+        u16 pin_number_index;
         u8 field_flags;
         u8 attribute;
         u8 field_type;
diff --git a/drivers/acpi/acpica/acobject.h b/drivers/acpi/acpica/acobject.h
index 22fb6449d3d6..8abb393dafab 100644
--- a/drivers/acpi/acpica/acobject.h
+++ b/drivers/acpi/acpica/acobject.h
@@ -264,6 +264,7 @@ struct acpi_object_region_field {
         ACPI_OBJECT_COMMON_HEADER ACPI_COMMON_FIELD_INFO u16 resource_length;
         union acpi_operand_object *region_obj;  /* Containing op_region object */
         u8 *resource_buffer;    /* resource_template for serial regions/fields */
+        u16 pin_number_index;   /* Index relative to previous Connection/Template */
 };
 
 struct acpi_object_bank_field {
diff --git a/drivers/acpi/acpica/dsfield.c b/drivers/acpi/acpica/dsfield.c
index 3661c8e90540..c57666196672 100644
--- a/drivers/acpi/acpica/dsfield.c
+++ b/drivers/acpi/acpica/dsfield.c
@@ -360,6 +360,7 @@ acpi_ds_get_field_names(struct acpi_create_field_info *info,
                          */
                         info->resource_buffer = NULL;
                         info->connection_node = NULL;
+                        info->pin_number_index = 0;
 
                         /*
                          * A Connection() is either an actual resource descriptor (buffer)
@@ -437,6 +438,7 @@ acpi_ds_get_field_names(struct acpi_create_field_info *info,
                         }
 
                         info->field_bit_position += info->field_bit_length;
+                        info->pin_number_index++;       /* Index relative to previous Connection() */
                         break;
 
                 default:
diff --git a/drivers/acpi/acpica/evregion.c b/drivers/acpi/acpica/evregion.c
index 9957297d1580..8eb8575e8c16 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)) {
diff --git a/drivers/acpi/acpica/exfield.c b/drivers/acpi/acpica/exfield.c
index 6907ce0c704c..b994845ed359 100644
--- a/drivers/acpi/acpica/exfield.c
+++ b/drivers/acpi/acpica/exfield.c
@@ -253,6 +253,37 @@ acpi_ex_read_data_from_field(struct acpi_walk_state * walk_state,
                 buffer = &buffer_desc->integer.value;
         }
 
+        if ((obj_desc->common.type == ACPI_TYPE_LOCAL_REGION_FIELD) &&
+            (obj_desc->field.region_obj->region.space_id ==
+             ACPI_ADR_SPACE_GPIO)) {
+                /*
+                 * For GPIO (general_purpose_io), the Address will be the bit offset
+                 * from the previous Connection() operator, making it effectively a
+                 * pin number index. The bit_length is the length of the field, which
+                 * is thus the number of pins.
+                 */
+                ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
+                                  "GPIO FieldRead [FROM]:  Pin %u Bits %u\n",
+                                  obj_desc->field.pin_number_index,
+                                  obj_desc->field.bit_length));
+
+                /* Lock entire transaction if requested */
+
+                acpi_ex_acquire_global_lock(obj_desc->common_field.field_flags);
+
+                /* Perform the write */
+
+                status = acpi_ex_access_region(obj_desc, 0,
+                                               (u64 *)buffer, ACPI_READ);
+                acpi_ex_release_global_lock(obj_desc->common_field.field_flags);
+                if (ACPI_FAILURE(status)) {
+                        acpi_ut_remove_reference(buffer_desc);
+                } else {
+                        *ret_buffer_desc = buffer_desc;
+                }
+                return_ACPI_STATUS(status);
+        }
+
         ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                           "FieldRead [TO]:   Obj %p, Type %X, Buf %p, ByteLen %X\n",
                           obj_desc, obj_desc->common.type, buffer,
@@ -413,6 +444,42 @@ acpi_ex_write_data_to_field(union acpi_operand_object *source_desc,
 
                 *result_desc = buffer_desc;
                 return_ACPI_STATUS(status);
+        } else if ((obj_desc->common.type == ACPI_TYPE_LOCAL_REGION_FIELD) &&
+                   (obj_desc->field.region_obj->region.space_id ==
+                    ACPI_ADR_SPACE_GPIO)) {
+                /*
+                 * For GPIO (general_purpose_io), we will bypass the entire field
+                 * mechanism and handoff the bit address and bit width directly to
+                 * the handler. The Address will be the bit offset
+                 * from the previous Connection() operator, making it effectively a
+                 * pin number index. The bit_length is the length of the field, which
+                 * is thus the number of pins.
+                 */
+                if (source_desc->common.type != ACPI_TYPE_INTEGER) {
+                        return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
+                }
+
+                ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
+                                  "GPIO FieldWrite [FROM]: (%s:%X), Val %.8X  [TO]:  Pin %u Bits %u\n",
+                                  acpi_ut_get_type_name(source_desc->common.
+                                                        type),
+                                  source_desc->common.type,
+                                  (u32)source_desc->integer.value,
+                                  obj_desc->field.pin_number_index,
+                                  obj_desc->field.bit_length));
+
+                buffer = &source_desc->integer.value;
+
+                /* Lock entire transaction if requested */
+
+                acpi_ex_acquire_global_lock(obj_desc->common_field.field_flags);
+
+                /* Perform the write */
+
+                status = acpi_ex_access_region(obj_desc, 0,
+                                               (u64 *)buffer, ACPI_WRITE);
+                acpi_ex_release_global_lock(obj_desc->common_field.field_flags);
+                return_ACPI_STATUS(status);
         }
 
         /* Get a pointer to the data to be written */
diff --git a/drivers/acpi/acpica/exprep.c b/drivers/acpi/acpica/exprep.c
index ee3f872870bc..118e942005e5 100644
--- a/drivers/acpi/acpica/exprep.c
+++ b/drivers/acpi/acpica/exprep.c
@@ -484,6 +484,8 @@ acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
                         obj_desc->field.resource_length = info->resource_length;
                 }
 
+                obj_desc->field.pin_number_index = info->pin_number_index;
+
                 /* Allow full data read from EC address space */
 
                 if ((obj_desc->field.region_obj->region.space_id ==