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exprep.c

/******************************************************************************
 *
 * Module Name: exprep - ACPI AML (p-code) execution - field prep utilities
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2007, R. Byron Moore
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <acpi/acpi.h>
#include <acpi/acinterp.h>
#include <acpi/amlcode.h>
#include <acpi/acnamesp.h>

#define _COMPONENT          ACPI_EXECUTER
ACPI_MODULE_NAME("exprep")

/* Local prototypes */
static u32
acpi_ex_decode_field_access(union acpi_operand_object *obj_desc,
                      u8 field_flags, u32 * return_byte_alignment);

#ifdef ACPI_UNDER_DEVELOPMENT

static u32
acpi_ex_generate_access(u32 field_bit_offset,
                  u32 field_bit_length, u32 region_length);

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_generate_access
 *
 * PARAMETERS:  field_bit_offset    - Start of field within parent region/buffer
 *              field_bit_length    - Length of field in bits
 *              region_length       - Length of parent in bytes
 *
 * RETURN:      Field granularity (8, 16, 32 or 64) and
 *              byte_alignment (1, 2, 3, or 4)
 *
 * DESCRIPTION: Generate an optimal access width for fields defined with the
 *              any_acc keyword.
 *
 * NOTE: Need to have the region_length in order to check for boundary
 *       conditions (end-of-region).  However, the region_length is a deferred
 *       operation.  Therefore, to complete this implementation, the generation
 *       of this access width must be deferred until the region length has
 *       been evaluated.
 *
 ******************************************************************************/

static u32
acpi_ex_generate_access(u32 field_bit_offset,
                  u32 field_bit_length, u32 region_length)
{
      u32 field_byte_length;
      u32 field_byte_offset;
      u32 field_byte_end_offset;
      u32 access_byte_width;
      u32 field_start_offset;
      u32 field_end_offset;
      u32 minimum_access_width = 0xFFFFFFFF;
      u32 minimum_accesses = 0xFFFFFFFF;
      u32 accesses;

      ACPI_FUNCTION_TRACE(ex_generate_access);

      /* Round Field start offset and length to "minimal" byte boundaries */

      field_byte_offset = ACPI_DIV_8(ACPI_ROUND_DOWN(field_bit_offset, 8));
      field_byte_end_offset = ACPI_DIV_8(ACPI_ROUND_UP(field_bit_length +
                                           field_bit_offset, 8));
      field_byte_length = field_byte_end_offset - field_byte_offset;

      ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                    "Bit length %d, Bit offset %d\n",
                    field_bit_length, field_bit_offset));

      ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                    "Byte Length %d, Byte Offset %d, End Offset %d\n",
                    field_byte_length, field_byte_offset,
                    field_byte_end_offset));

      /*
       * Iterative search for the maximum access width that is both aligned
       * and does not go beyond the end of the region
       *
       * Start at byte_acc and work upwards to qword_acc max. (1,2,4,8 bytes)
       */
      for (access_byte_width = 1; access_byte_width <= 8;
           access_byte_width <<= 1) {
            /*
             * 1) Round end offset up to next access boundary and make sure that
             *    this does not go beyond the end of the parent region.
             * 2) When the Access width is greater than the field_byte_length, we
             *    are done. (This does not optimize for the perfectly aligned
             *    case yet).
             */
            if (ACPI_ROUND_UP(field_byte_end_offset, access_byte_width) <=
                region_length) {
                  field_start_offset =
                      ACPI_ROUND_DOWN(field_byte_offset,
                                  access_byte_width) /
                      access_byte_width;

                  field_end_offset =
                      ACPI_ROUND_UP((field_byte_length +
                                 field_byte_offset),
                                access_byte_width) /
                      access_byte_width;

                  accesses = field_end_offset - field_start_offset;

                  ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                                "AccessWidth %d end is within region\n",
                                access_byte_width));

                  ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                                "Field Start %d, Field End %d -- requires %d accesses\n",
                                field_start_offset, field_end_offset,
                                accesses));

                  /* Single access is optimal */

                  if (accesses <= 1) {
                        ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                                      "Entire field can be accessed with one operation of size %d\n",
                                      access_byte_width));
                        return_VALUE(access_byte_width);
                  }

                  /*
                   * Fits in the region, but requires more than one read/write.
                   * try the next wider access on next iteration
                   */
                  if (accesses < minimum_accesses) {
                        minimum_accesses = accesses;
                        minimum_access_width = access_byte_width;
                  }
            } else {
                  ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                                "AccessWidth %d end is NOT within region\n",
                                access_byte_width));
                  if (access_byte_width == 1) {
                        ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                                      "Field goes beyond end-of-region!\n"));

                        /* Field does not fit in the region at all */

                        return_VALUE(0);
                  }

                  /*
                   * This width goes beyond the end-of-region, back off to
                   * previous access
                   */
                  ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                                "Backing off to previous optimal access width of %d\n",
                                minimum_access_width));
                  return_VALUE(minimum_access_width);
            }
      }

      /*
       * Could not read/write field with one operation,
       * just use max access width
       */
      ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                    "Cannot access field in one operation, using width 8\n"));
      return_VALUE(8);
}
#endif                        /* ACPI_UNDER_DEVELOPMENT */

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_decode_field_access
 *
 * PARAMETERS:  obj_desc            - Field object
 *              field_flags         - Encoded fieldflags (contains access bits)
 *              return_byte_alignment - Where the byte alignment is returned
 *
 * RETURN:      Field granularity (8, 16, 32 or 64) and
 *              byte_alignment (1, 2, 3, or 4)
 *
 * DESCRIPTION: Decode the access_type bits of a field definition.
 *
 ******************************************************************************/

static u32
acpi_ex_decode_field_access(union acpi_operand_object *obj_desc,
                      u8 field_flags, u32 * return_byte_alignment)
{
      u32 access;
      u32 byte_alignment;
      u32 bit_length;

      ACPI_FUNCTION_TRACE(ex_decode_field_access);

      access = (field_flags & AML_FIELD_ACCESS_TYPE_MASK);

      switch (access) {
      case AML_FIELD_ACCESS_ANY:

#ifdef ACPI_UNDER_DEVELOPMENT
            byte_alignment =
                acpi_ex_generate_access(obj_desc->common_field.
                                  start_field_bit_offset,
                                  obj_desc->common_field.bit_length,
                                  0xFFFFFFFF
                                  /* Temp until we pass region_length as parameter */
                );
            bit_length = byte_alignment * 8;
#endif

            byte_alignment = 1;
            bit_length = 8;
            break;

      case AML_FIELD_ACCESS_BYTE:
      case AML_FIELD_ACCESS_BUFFER: /* ACPI 2.0 (SMBus Buffer) */
            byte_alignment = 1;
            bit_length = 8;
            break;

      case AML_FIELD_ACCESS_WORD:
            byte_alignment = 2;
            bit_length = 16;
            break;

      case AML_FIELD_ACCESS_DWORD:
            byte_alignment = 4;
            bit_length = 32;
            break;

      case AML_FIELD_ACCESS_QWORD:  /* ACPI 2.0 */
            byte_alignment = 8;
            bit_length = 64;
            break;

      default:
            /* Invalid field access type */

            ACPI_ERROR((AE_INFO, "Unknown field access type %X", access));
            return_UINT32(0);
      }

      if (ACPI_GET_OBJECT_TYPE(obj_desc) == ACPI_TYPE_BUFFER_FIELD) {
            /*
             * buffer_field access can be on any byte boundary, so the
             * byte_alignment is always 1 byte -- regardless of any byte_alignment
             * implied by the field access type.
             */
            byte_alignment = 1;
      }

      *return_byte_alignment = byte_alignment;
      return_UINT32(bit_length);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_prep_common_field_object
 *
 * PARAMETERS:  obj_desc            - The field object
 *              field_flags         - Access, lock_rule, and update_rule.
 *                                    The format of a field_flag is described
 *                                    in the ACPI specification
 *              field_attribute     - Special attributes (not used)
 *              field_bit_position  - Field start position
 *              field_bit_length    - Field length in number of bits
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Initialize the areas of the field object that are common
 *              to the various types of fields.  Note: This is very "sensitive"
 *              code because we are solving the general case for field
 *              alignment.
 *
 ******************************************************************************/

acpi_status
acpi_ex_prep_common_field_object(union acpi_operand_object *obj_desc,
                         u8 field_flags,
                         u8 field_attribute,
                         u32 field_bit_position, u32 field_bit_length)
{
      u32 access_bit_width;
      u32 byte_alignment;
      u32 nearest_byte_address;

      ACPI_FUNCTION_TRACE(ex_prep_common_field_object);

      /*
       * Note: the structure being initialized is the
       * ACPI_COMMON_FIELD_INFO;  No structure fields outside of the common
       * area are initialized by this procedure.
       */
      obj_desc->common_field.field_flags = field_flags;
      obj_desc->common_field.attribute = field_attribute;
      obj_desc->common_field.bit_length = field_bit_length;

      /*
       * Decode the access type so we can compute offsets.  The access type gives
       * two pieces of information - the width of each field access and the
       * necessary byte_alignment (address granularity) of the access.
       *
       * For any_acc, the access_bit_width is the largest width that is both
       * necessary and possible in an attempt to access the whole field in one
       * I/O operation.  However, for any_acc, the byte_alignment is always one
       * byte.
       *
       * For all Buffer Fields, the byte_alignment is always one byte.
       *
       * For all other access types (Byte, Word, Dword, Qword), the Bitwidth is
       * the same (equivalent) as the byte_alignment.
       */
      access_bit_width = acpi_ex_decode_field_access(obj_desc, field_flags,
                                           &byte_alignment);
      if (!access_bit_width) {
            return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
      }

      /* Setup width (access granularity) fields */

      obj_desc->common_field.access_byte_width = (u8)
          ACPI_DIV_8(access_bit_width);   /* 1,  2,  4,  8 */

      obj_desc->common_field.access_bit_width = (u8) access_bit_width;

      /*
       * base_byte_offset is the address of the start of the field within the
       * region.  It is the byte address of the first *datum* (field-width data
       * unit) of the field. (i.e., the first datum that contains at least the
       * first *bit* of the field.)
       *
       * Note: byte_alignment is always either equal to the access_bit_width or 8
       * (Byte access), and it defines the addressing granularity of the parent
       * region or buffer.
       */
      nearest_byte_address =
          ACPI_ROUND_BITS_DOWN_TO_BYTES(field_bit_position);
      obj_desc->common_field.base_byte_offset = (u32)
          ACPI_ROUND_DOWN(nearest_byte_address, byte_alignment);

      /*
       * start_field_bit_offset is the offset of the first bit of the field within
       * a field datum.
       */
      obj_desc->common_field.start_field_bit_offset = (u8)
          (field_bit_position -
           ACPI_MUL_8(obj_desc->common_field.base_byte_offset));

      /*
       * Does the entire field fit within a single field access element? (datum)
       * (i.e., without crossing a datum boundary)
       */
      if ((obj_desc->common_field.start_field_bit_offset +
           field_bit_length) <= (u16) access_bit_width) {
            obj_desc->common.flags |= AOPOBJ_SINGLE_DATUM;
      }

      return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_prep_field_value
 *
 * PARAMETERS:  Info    - Contains all field creation info
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Construct an union acpi_operand_object of type def_field and
 *              connect it to the parent Node.
 *
 ******************************************************************************/

acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
{
      union acpi_operand_object *obj_desc;
      u32 type;
      acpi_status status;

      ACPI_FUNCTION_TRACE(ex_prep_field_value);

      /* Parameter validation */

      if (info->field_type != ACPI_TYPE_LOCAL_INDEX_FIELD) {
            if (!info->region_node) {
                  ACPI_ERROR((AE_INFO, "Null RegionNode"));
                  return_ACPI_STATUS(AE_AML_NO_OPERAND);
            }

            type = acpi_ns_get_type(info->region_node);
            if (type != ACPI_TYPE_REGION) {
                  ACPI_ERROR((AE_INFO,
                            "Needed Region, found type %X (%s)",
                            type, acpi_ut_get_type_name(type)));

                  return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
            }
      }

      /* Allocate a new field object */

      obj_desc = acpi_ut_create_internal_object(info->field_type);
      if (!obj_desc) {
            return_ACPI_STATUS(AE_NO_MEMORY);
      }

      /* Initialize areas of the object that are common to all fields */

      obj_desc->common_field.node = info->field_node;
      status = acpi_ex_prep_common_field_object(obj_desc, info->field_flags,
                                      info->attribute,
                                      info->field_bit_position,
                                      info->field_bit_length);
      if (ACPI_FAILURE(status)) {
            acpi_ut_delete_object_desc(obj_desc);
            return_ACPI_STATUS(status);
      }

      /* Initialize areas of the object that are specific to the field type */

      switch (info->field_type) {
      case ACPI_TYPE_LOCAL_REGION_FIELD:

            obj_desc->field.region_obj =
                acpi_ns_get_attached_object(info->region_node);

            /* An additional reference for the container */

            acpi_ut_add_reference(obj_desc->field.region_obj);

            ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                          "RegionField: BitOff %X, Off %X, Gran %X, Region %p\n",
                          obj_desc->field.start_field_bit_offset,
                          obj_desc->field.base_byte_offset,
                          obj_desc->field.access_byte_width,
                          obj_desc->field.region_obj));
            break;

      case ACPI_TYPE_LOCAL_BANK_FIELD:

            obj_desc->bank_field.value = info->bank_value;
            obj_desc->bank_field.region_obj =
                acpi_ns_get_attached_object(info->region_node);
            obj_desc->bank_field.bank_obj =
                acpi_ns_get_attached_object(info->register_node);

            /* An additional reference for the attached objects */

            acpi_ut_add_reference(obj_desc->bank_field.region_obj);
            acpi_ut_add_reference(obj_desc->bank_field.bank_obj);

            ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                          "Bank Field: BitOff %X, Off %X, Gran %X, Region %p, BankReg %p\n",
                          obj_desc->bank_field.start_field_bit_offset,
                          obj_desc->bank_field.base_byte_offset,
                          obj_desc->field.access_byte_width,
                          obj_desc->bank_field.region_obj,
                          obj_desc->bank_field.bank_obj));
            break;

      case ACPI_TYPE_LOCAL_INDEX_FIELD:

            /* Get the Index and Data registers */

            obj_desc->index_field.index_obj =
                acpi_ns_get_attached_object(info->register_node);
            obj_desc->index_field.data_obj =
                acpi_ns_get_attached_object(info->data_register_node);

            if (!obj_desc->index_field.data_obj
                || !obj_desc->index_field.index_obj) {
                  ACPI_ERROR((AE_INFO,
                            "Null Index Object during field prep"));
                  acpi_ut_delete_object_desc(obj_desc);
                  return_ACPI_STATUS(AE_AML_INTERNAL);
            }

            /* An additional reference for the attached objects */

            acpi_ut_add_reference(obj_desc->index_field.data_obj);
            acpi_ut_add_reference(obj_desc->index_field.index_obj);

            /*
             * April 2006: Changed to match MS behavior
             *
             * The value written to the Index register is the byte offset of the
             * target field in units of the granularity of the index_field
             *
             * Previously, the value was calculated as an index in terms of the
             * width of the Data register, as below:
             *
             *      obj_desc->index_field.Value = (u32)
             *          (Info->field_bit_position / ACPI_MUL_8 (
             *              obj_desc->Field.access_byte_width));
             *
             * February 2006: Tried value as a byte offset:
             *      obj_desc->index_field.Value = (u32)
             *          ACPI_DIV_8 (Info->field_bit_position);
             */
            obj_desc->index_field.value =
                (u32) ACPI_ROUND_DOWN(ACPI_DIV_8(info->field_bit_position),
                                obj_desc->index_field.
                                access_byte_width);

            ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                          "IndexField: BitOff %X, Off %X, Value %X, Gran %X, Index %p, Data %p\n",
                          obj_desc->index_field.start_field_bit_offset,
                          obj_desc->index_field.base_byte_offset,
                          obj_desc->index_field.value,
                          obj_desc->field.access_byte_width,
                          obj_desc->index_field.index_obj,
                          obj_desc->index_field.data_obj));
            break;

      default:
            /* No other types should get here */
            break;
      }

      /*
       * Store the constructed descriptor (obj_desc) into the parent Node,
       * preserving the current type of that named_obj.
       */
      status = acpi_ns_attach_object(info->field_node, obj_desc,
                               acpi_ns_get_type(info->field_node));

      ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                    "Set NamedObj %p [%4.4s], ObjDesc %p\n",
                    info->field_node,
                    acpi_ut_get_node_name(info->field_node), obj_desc));

      /* Remove local reference to the object */

      acpi_ut_remove_reference(obj_desc);
      return_ACPI_STATUS(status);
}

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