ACPICA: Split large interpreter file
authorBob Moore <robert.moore@intel.com>
Wed, 3 Oct 2018 18:45:37 +0000 (11:45 -0700)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Thu, 4 Oct 2018 07:06:27 +0000 (09:06 +0200)
New file: exserial.c

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/acpi/acpica/Makefile
drivers/acpi/acpica/acinterp.h
drivers/acpi/acpica/exfield.c
drivers/acpi/acpica/exserial.c [new file with mode: 0644]

index 71f6f26..b14621d 100644 (file)
@@ -65,6 +65,7 @@ acpi-y +=             \
        exresnte.o      \
        exresolv.o      \
        exresop.o       \
+       exserial.o      \
        exstore.o       \
        exstoren.o      \
        exstorob.o      \
index 6a53d3b..c5b2be0 100644 (file)
@@ -270,6 +270,26 @@ acpi_ex_prep_common_field_object(union acpi_operand_object *obj_desc,
 
 acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info);
 
+/*
+ * exserial - field_unit support for serial address spaces
+ */
+acpi_status
+acpi_ex_read_serial_bus(union acpi_operand_object *obj_desc,
+                       union acpi_operand_object **return_buffer);
+
+acpi_status
+acpi_ex_write_serial_bus(union acpi_operand_object *source_desc,
+                        union acpi_operand_object *obj_desc,
+                        union acpi_operand_object **return_buffer);
+
+acpi_status
+acpi_ex_read_gpio(union acpi_operand_object *obj_desc, void *buffer);
+
+acpi_status
+acpi_ex_write_gpio(union acpi_operand_object *source_desc,
+                  union acpi_operand_object *obj_desc,
+                  union acpi_operand_object **return_buffer);
+
 /*
  * exsystem - Interface to OS services
  */
index f3e5e98..e5798f1 100644 (file)
 #define _COMPONENT          ACPI_EXECUTER
 ACPI_MODULE_NAME("exfield")
 
-/* Local prototypes */
-static acpi_status
-acpi_ex_read_serial_bus(union acpi_operand_object *obj_desc,
-                       union acpi_operand_object **return_buffer);
-
-static acpi_status
-acpi_ex_write_serial_bus(union acpi_operand_object *source_desc,
-                        union acpi_operand_object *obj_desc,
-                        union acpi_operand_object **return_buffer);
-
-static acpi_status
-acpi_ex_read_gpio(union acpi_operand_object *obj_desc, void *buffer);
-
-static acpi_status
-acpi_ex_write_gpio(union acpi_operand_object *source_desc,
-                  union acpi_operand_object *obj_desc,
-                  union acpi_operand_object **return_buffer);
-
 /*
  * This table maps the various Attrib protocols to the byte transfer
  * length. Used for the generic serial bus.
  */
 #define ACPI_INVALID_PROTOCOL_ID        0x80
 #define ACPI_MAX_PROTOCOL_ID            0x0F
-
 const u8 acpi_protocol_lengths[] = {
        ACPI_INVALID_PROTOCOL_ID,       /* 0 - reserved */
        ACPI_INVALID_PROTOCOL_ID,       /* 1 - reserved */
@@ -343,348 +324,3 @@ acpi_ex_write_data_to_field(union acpi_operand_object *source_desc,
        acpi_ex_release_global_lock(obj_desc->common_field.field_flags);
        return_ACPI_STATUS(status);
 }
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ex_read_gpio
- *
- * PARAMETERS:  obj_desc            - The named field to read
- *              buffer              - Where the return data is returnd
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Read from a named field that references a Generic Serial Bus
- *              field
- *
- ******************************************************************************/
-
-static acpi_status
-acpi_ex_read_gpio(union acpi_operand_object *obj_desc, void *buffer)
-{
-       acpi_status status;
-
-       ACPI_FUNCTION_TRACE_PTR(ex_read_gpio, obj_desc);
-
-       /*
-        * 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 read */
-
-       status = acpi_ex_access_region(obj_desc, 0, (u64 *)buffer, ACPI_READ);
-
-       acpi_ex_release_global_lock(obj_desc->common_field.field_flags);
-       return_ACPI_STATUS(status);
-}
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ex_write_gpio
- *
- * PARAMETERS:  source_desc         - Contains data to write. Expect to be
- *                                    an Integer object.
- *              obj_desc            - The named field
- *              result_desc         - Where the return value is returned, if any
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Write to a named field that references a General Purpose I/O
- *              field.
- *
- ******************************************************************************/
-
-static acpi_status
-acpi_ex_write_gpio(union acpi_operand_object *source_desc,
-                  union acpi_operand_object *obj_desc,
-                  union acpi_operand_object **return_buffer)
-{
-       acpi_status status;
-       void *buffer;
-
-       ACPI_FUNCTION_TRACE_PTR(ex_write_gpio, obj_desc);
-
-       /*
-        * 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), Value %.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);
-}
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ex_read_serial_bus
- *
- * PARAMETERS:  obj_desc            - The named field to read
- *              return_buffer       - Where the return value is returned, if any
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Read from a named field that references a serial bus
- *              (SMBus, IPMI, or GSBus).
- *
- ******************************************************************************/
-
-static acpi_status
-acpi_ex_read_serial_bus(union acpi_operand_object *obj_desc,
-                       union acpi_operand_object **return_buffer)
-{
-       acpi_status status;
-       u32 buffer_length;
-       union acpi_operand_object *buffer_desc;
-       u32 function;
-       u16 accessor_type;
-
-       ACPI_FUNCTION_TRACE_PTR(ex_read_serial_bus, obj_desc);
-
-       /*
-        * This is an SMBus, GSBus or IPMI read. We must create a buffer to
-        * hold the data and then directly access the region handler.
-        *
-        * Note: SMBus and GSBus protocol value is passed in upper 16-bits
-        * of Function
-        *
-        * Common buffer format:
-        *     Status;    (Byte 0 of the data buffer)
-        *     Length;    (Byte 1 of the data buffer)
-        *     Data[x-1]: (Bytes 2-x of the arbitrary length data buffer)
-        */
-       switch (obj_desc->field.region_obj->region.space_id) {
-       case ACPI_ADR_SPACE_SMBUS:
-
-               buffer_length = ACPI_SMBUS_BUFFER_SIZE;
-               function = ACPI_READ | (obj_desc->field.attribute << 16);
-               break;
-
-       case ACPI_ADR_SPACE_IPMI:
-
-               buffer_length = ACPI_IPMI_BUFFER_SIZE;
-               function = ACPI_READ;
-               break;
-
-       case ACPI_ADR_SPACE_GSBUS:
-
-               accessor_type = obj_desc->field.attribute;
-               if (accessor_type == AML_FIELD_ATTRIB_RAW_PROCESS_BYTES) {
-                       ACPI_ERROR((AE_INFO,
-                                   "Invalid direct read using bidirectional write-then-read protocol"));
-
-                       return_ACPI_STATUS(AE_AML_PROTOCOL);
-               }
-
-               status =
-                   acpi_ex_get_protocol_buffer_length(accessor_type,
-                                                      &buffer_length);
-               if (ACPI_FAILURE(status)) {
-                       ACPI_ERROR((AE_INFO,
-                                   "Invalid protocol ID for GSBus: 0x%4.4X",
-                                   accessor_type));
-
-                       return_ACPI_STATUS(status);
-               }
-
-               /* Add header length to get the full size of the buffer */
-
-               buffer_length += ACPI_SERIAL_HEADER_SIZE;
-               function = ACPI_READ | (accessor_type << 16);
-               break;
-
-       default:
-               return_ACPI_STATUS(AE_AML_INVALID_SPACE_ID);
-       }
-
-       /* Create the local transfer buffer that is returned to the caller */
-
-       buffer_desc = acpi_ut_create_buffer_object(buffer_length);
-       if (!buffer_desc) {
-               return_ACPI_STATUS(AE_NO_MEMORY);
-       }
-
-       /* Lock entire transaction if requested */
-
-       acpi_ex_acquire_global_lock(obj_desc->common_field.field_flags);
-
-       /* Call the region handler for the write-then-read */
-
-       status = acpi_ex_access_region(obj_desc, 0,
-                                      ACPI_CAST_PTR(u64,
-                                                    buffer_desc->buffer.
-                                                    pointer), function);
-       acpi_ex_release_global_lock(obj_desc->common_field.field_flags);
-
-       *return_buffer = buffer_desc;
-       return_ACPI_STATUS(status);
-}
-
-/*******************************************************************************
- *
- * FUNCTION:    acpi_ex_write_serial_bus
- *
- * PARAMETERS:  source_desc         - Contains data to write
- *              obj_desc            - The named field
- *              return_buffer       - Where the return value is returned, if any
- *
- * RETURN:      Status
- *
- * DESCRIPTION: Write to a named field that references a serial bus
- *              (SMBus, IPMI, GSBus).
- *
- ******************************************************************************/
-
-static acpi_status
-acpi_ex_write_serial_bus(union acpi_operand_object *source_desc,
-                        union acpi_operand_object *obj_desc,
-                        union acpi_operand_object **return_buffer)
-{
-       acpi_status status;
-       u32 buffer_length;
-       u32 data_length;
-       void *buffer;
-       union acpi_operand_object *buffer_desc;
-       u32 function;
-       u16 accessor_type;
-
-       ACPI_FUNCTION_TRACE_PTR(ex_write_serial_bus, obj_desc);
-
-       /*
-        * This is an SMBus, GSBus or IPMI write. We will bypass the entire
-        * field mechanism and handoff the buffer directly to the handler.
-        * For these address spaces, the buffer is bidirectional; on a
-        * write, return data is returned in the same buffer.
-        *
-        * Source must be a buffer of sufficient size, these are fixed size:
-        * ACPI_SMBUS_BUFFER_SIZE, or ACPI_IPMI_BUFFER_SIZE.
-        *
-        * Note: SMBus and GSBus protocol type is passed in upper 16-bits
-        * of Function
-        *
-        * Common buffer format:
-        *     Status;    (Byte 0 of the data buffer)
-        *     Length;    (Byte 1 of the data buffer)
-        *     Data[x-1]: (Bytes 2-x of the arbitrary length data buffer)
-        */
-       if (source_desc->common.type != ACPI_TYPE_BUFFER) {
-               ACPI_ERROR((AE_INFO,
-                           "SMBus/IPMI/GenericSerialBus write requires "
-                           "Buffer, found type %s",
-                           acpi_ut_get_object_type_name(source_desc)));
-
-               return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
-       }
-
-       switch (obj_desc->field.region_obj->region.space_id) {
-       case ACPI_ADR_SPACE_SMBUS:
-
-               buffer_length = ACPI_SMBUS_BUFFER_SIZE;
-               data_length = ACPI_SMBUS_DATA_SIZE;
-               function = ACPI_WRITE | (obj_desc->field.attribute << 16);
-               break;
-
-       case ACPI_ADR_SPACE_IPMI:
-
-               buffer_length = ACPI_IPMI_BUFFER_SIZE;
-               data_length = ACPI_IPMI_DATA_SIZE;
-               function = ACPI_WRITE;
-               break;
-
-       case ACPI_ADR_SPACE_GSBUS:
-
-               accessor_type = obj_desc->field.attribute;
-               status =
-                   acpi_ex_get_protocol_buffer_length(accessor_type,
-                                                      &buffer_length);
-               if (ACPI_FAILURE(status)) {
-                       ACPI_ERROR((AE_INFO,
-                                   "Invalid protocol ID for GSBus: 0x%4.4X",
-                                   accessor_type));
-
-                       return_ACPI_STATUS(status);
-               }
-
-               /* Add header length to get the full size of the buffer */
-
-               buffer_length += ACPI_SERIAL_HEADER_SIZE;
-               data_length = source_desc->buffer.pointer[1];
-               function = ACPI_WRITE | (accessor_type << 16);
-               break;
-
-       default:
-               return_ACPI_STATUS(AE_AML_INVALID_SPACE_ID);
-       }
-
-#if 0
-       OBSOLETE ?
-           /* Check for possible buffer overflow */
-           if (data_length > source_desc->buffer.length) {
-               ACPI_ERROR((AE_INFO,
-                           "Length in buffer header (%u)(%u) is greater than "
-                           "the physical buffer length (%u) and will overflow",
-                           data_length, buffer_length,
-                           source_desc->buffer.length));
-
-               return_ACPI_STATUS(AE_AML_BUFFER_LIMIT);
-       }
-#endif
-
-       /* Create the transfer/bidirectional/return buffer */
-
-       buffer_desc = acpi_ut_create_buffer_object(buffer_length);
-       if (!buffer_desc) {
-               return_ACPI_STATUS(AE_NO_MEMORY);
-       }
-
-       /* Copy the input buffer data to the transfer buffer */
-
-       buffer = buffer_desc->buffer.pointer;
-       memcpy(buffer, source_desc->buffer.pointer, data_length);
-
-       /* Lock entire transaction if requested */
-
-       acpi_ex_acquire_global_lock(obj_desc->common_field.field_flags);
-
-       /*
-        * Perform the write (returns status and perhaps data in the
-        * same buffer)
-        */
-       status = acpi_ex_access_region(obj_desc, 0, (u64 *)buffer, function);
-       acpi_ex_release_global_lock(obj_desc->common_field.field_flags);
-
-       *return_buffer = buffer_desc;
-       return_ACPI_STATUS(status);
-}
diff --git a/drivers/acpi/acpica/exserial.c b/drivers/acpi/acpica/exserial.c
new file mode 100644 (file)
index 0000000..0d42f30
--- /dev/null
@@ -0,0 +1,360 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: exserial - field_unit support for serial address spaces
+ *
+ * Copyright (C) 2000 - 2018, Intel Corp.
+ *
+ *****************************************************************************/
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+#include "acdispat.h"
+#include "acinterp.h"
+#include "amlcode.h"
+
+#define _COMPONENT          ACPI_EXECUTER
+ACPI_MODULE_NAME("exserial")
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ex_read_gpio
+ *
+ * PARAMETERS:  obj_desc            - The named field to read
+ *              buffer              - Where the return data is returnd
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Read from a named field that references a Generic Serial Bus
+ *              field
+ *
+ ******************************************************************************/
+acpi_status acpi_ex_read_gpio(union acpi_operand_object *obj_desc, void *buffer)
+{
+       acpi_status status;
+
+       ACPI_FUNCTION_TRACE_PTR(ex_read_gpio, obj_desc);
+
+       /*
+        * 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 read */
+
+       status = acpi_ex_access_region(obj_desc, 0, (u64 *)buffer, ACPI_READ);
+
+       acpi_ex_release_global_lock(obj_desc->common_field.field_flags);
+       return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ex_write_gpio
+ *
+ * PARAMETERS:  source_desc         - Contains data to write. Expect to be
+ *                                    an Integer object.
+ *              obj_desc            - The named field
+ *              result_desc         - Where the return value is returned, if any
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Write to a named field that references a General Purpose I/O
+ *              field.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ex_write_gpio(union acpi_operand_object *source_desc,
+                  union acpi_operand_object *obj_desc,
+                  union acpi_operand_object **return_buffer)
+{
+       acpi_status status;
+       void *buffer;
+
+       ACPI_FUNCTION_TRACE_PTR(ex_write_gpio, obj_desc);
+
+       /*
+        * 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), Value %.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);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ex_read_serial_bus
+ *
+ * PARAMETERS:  obj_desc            - The named field to read
+ *              return_buffer       - Where the return value is returned, if any
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Read from a named field that references a serial bus
+ *              (SMBus, IPMI, or GSBus).
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ex_read_serial_bus(union acpi_operand_object *obj_desc,
+                       union acpi_operand_object **return_buffer)
+{
+       acpi_status status;
+       u32 buffer_length;
+       union acpi_operand_object *buffer_desc;
+       u32 function;
+       u16 accessor_type;
+
+       ACPI_FUNCTION_TRACE_PTR(ex_read_serial_bus, obj_desc);
+
+       /*
+        * This is an SMBus, GSBus or IPMI read. We must create a buffer to
+        * hold the data and then directly access the region handler.
+        *
+        * Note: SMBus and GSBus protocol value is passed in upper 16-bits
+        * of Function
+        *
+        * Common buffer format:
+        *     Status;    (Byte 0 of the data buffer)
+        *     Length;    (Byte 1 of the data buffer)
+        *     Data[x-1]: (Bytes 2-x of the arbitrary length data buffer)
+        */
+       switch (obj_desc->field.region_obj->region.space_id) {
+       case ACPI_ADR_SPACE_SMBUS:
+
+               buffer_length = ACPI_SMBUS_BUFFER_SIZE;
+               function = ACPI_READ | (obj_desc->field.attribute << 16);
+               break;
+
+       case ACPI_ADR_SPACE_IPMI:
+
+               buffer_length = ACPI_IPMI_BUFFER_SIZE;
+               function = ACPI_READ;
+               break;
+
+       case ACPI_ADR_SPACE_GSBUS:
+
+               accessor_type = obj_desc->field.attribute;
+               if (accessor_type == AML_FIELD_ATTRIB_RAW_PROCESS_BYTES) {
+                       ACPI_ERROR((AE_INFO,
+                                   "Invalid direct read using bidirectional write-then-read protocol"));
+
+                       return_ACPI_STATUS(AE_AML_PROTOCOL);
+               }
+
+               status =
+                   acpi_ex_get_protocol_buffer_length(accessor_type,
+                                                      &buffer_length);
+               if (ACPI_FAILURE(status)) {
+                       ACPI_ERROR((AE_INFO,
+                                   "Invalid protocol ID for GSBus: 0x%4.4X",
+                                   accessor_type));
+
+                       return_ACPI_STATUS(status);
+               }
+
+               /* Add header length to get the full size of the buffer */
+
+               buffer_length += ACPI_SERIAL_HEADER_SIZE;
+               function = ACPI_READ | (accessor_type << 16);
+               break;
+
+       default:
+               return_ACPI_STATUS(AE_AML_INVALID_SPACE_ID);
+       }
+
+       /* Create the local transfer buffer that is returned to the caller */
+
+       buffer_desc = acpi_ut_create_buffer_object(buffer_length);
+       if (!buffer_desc) {
+               return_ACPI_STATUS(AE_NO_MEMORY);
+       }
+
+       /* Lock entire transaction if requested */
+
+       acpi_ex_acquire_global_lock(obj_desc->common_field.field_flags);
+
+       /* Call the region handler for the write-then-read */
+
+       status = acpi_ex_access_region(obj_desc, 0,
+                                      ACPI_CAST_PTR(u64,
+                                                    buffer_desc->buffer.
+                                                    pointer), function);
+       acpi_ex_release_global_lock(obj_desc->common_field.field_flags);
+
+       *return_buffer = buffer_desc;
+       return_ACPI_STATUS(status);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_ex_write_serial_bus
+ *
+ * PARAMETERS:  source_desc         - Contains data to write
+ *              obj_desc            - The named field
+ *              return_buffer       - Where the return value is returned, if any
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Write to a named field that references a serial bus
+ *              (SMBus, IPMI, GSBus).
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_ex_write_serial_bus(union acpi_operand_object *source_desc,
+                        union acpi_operand_object *obj_desc,
+                        union acpi_operand_object **return_buffer)
+{
+       acpi_status status;
+       u32 buffer_length;
+       u32 data_length;
+       void *buffer;
+       union acpi_operand_object *buffer_desc;
+       u32 function;
+       u16 accessor_type;
+
+       ACPI_FUNCTION_TRACE_PTR(ex_write_serial_bus, obj_desc);
+
+       /*
+        * This is an SMBus, GSBus or IPMI write. We will bypass the entire
+        * field mechanism and handoff the buffer directly to the handler.
+        * For these address spaces, the buffer is bidirectional; on a
+        * write, return data is returned in the same buffer.
+        *
+        * Source must be a buffer of sufficient size, these are fixed size:
+        * ACPI_SMBUS_BUFFER_SIZE, or ACPI_IPMI_BUFFER_SIZE.
+        *
+        * Note: SMBus and GSBus protocol type is passed in upper 16-bits
+        * of Function
+        *
+        * Common buffer format:
+        *     Status;    (Byte 0 of the data buffer)
+        *     Length;    (Byte 1 of the data buffer)
+        *     Data[x-1]: (Bytes 2-x of the arbitrary length data buffer)
+        */
+       if (source_desc->common.type != ACPI_TYPE_BUFFER) {
+               ACPI_ERROR((AE_INFO,
+                           "SMBus/IPMI/GenericSerialBus write requires "
+                           "Buffer, found type %s",
+                           acpi_ut_get_object_type_name(source_desc)));
+
+               return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
+       }
+
+       switch (obj_desc->field.region_obj->region.space_id) {
+       case ACPI_ADR_SPACE_SMBUS:
+
+               buffer_length = ACPI_SMBUS_BUFFER_SIZE;
+               data_length = ACPI_SMBUS_DATA_SIZE;
+               function = ACPI_WRITE | (obj_desc->field.attribute << 16);
+               break;
+
+       case ACPI_ADR_SPACE_IPMI:
+
+               buffer_length = ACPI_IPMI_BUFFER_SIZE;
+               data_length = ACPI_IPMI_DATA_SIZE;
+               function = ACPI_WRITE;
+               break;
+
+       case ACPI_ADR_SPACE_GSBUS:
+
+               accessor_type = obj_desc->field.attribute;
+               status =
+                   acpi_ex_get_protocol_buffer_length(accessor_type,
+                                                      &buffer_length);
+               if (ACPI_FAILURE(status)) {
+                       ACPI_ERROR((AE_INFO,
+                                   "Invalid protocol ID for GSBus: 0x%4.4X",
+                                   accessor_type));
+
+                       return_ACPI_STATUS(status);
+               }
+
+               /* Add header length to get the full size of the buffer */
+
+               buffer_length += ACPI_SERIAL_HEADER_SIZE;
+               data_length = source_desc->buffer.pointer[1];
+               function = ACPI_WRITE | (accessor_type << 16);
+               break;
+
+       default:
+               return_ACPI_STATUS(AE_AML_INVALID_SPACE_ID);
+       }
+
+#if 0
+       OBSOLETE ?
+           /* Check for possible buffer overflow */
+           if (data_length > source_desc->buffer.length) {
+               ACPI_ERROR((AE_INFO,
+                           "Length in buffer header (%u)(%u) is greater than "
+                           "the physical buffer length (%u) and will overflow",
+                           data_length, buffer_length,
+                           source_desc->buffer.length));
+
+               return_ACPI_STATUS(AE_AML_BUFFER_LIMIT);
+       }
+#endif
+
+       /* Create the transfer/bidirectional/return buffer */
+
+       buffer_desc = acpi_ut_create_buffer_object(buffer_length);
+       if (!buffer_desc) {
+               return_ACPI_STATUS(AE_NO_MEMORY);
+       }
+
+       /* Copy the input buffer data to the transfer buffer */
+
+       buffer = buffer_desc->buffer.pointer;
+       memcpy(buffer, source_desc->buffer.pointer, data_length);
+
+       /* Lock entire transaction if requested */
+
+       acpi_ex_acquire_global_lock(obj_desc->common_field.field_flags);
+
+       /*
+        * Perform the write (returns status and perhaps data in the
+        * same buffer)
+        */
+       status = acpi_ex_access_region(obj_desc, 0, (u64 *)buffer, function);
+       acpi_ex_release_global_lock(obj_desc->common_field.field_flags);
+
+       *return_buffer = buffer_desc;
+       return_ACPI_STATUS(status);
+}