Quelle  exprep.c   Sprache: C

// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: exprep - ACPI AML field prep utilities
 *
 * Copyright (C) 2000 - 2025, Intel Corp.
 *
 *****************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"
#include "acinterp.h"
#include "amlcode.h"
#include "acnamesp.h"
#include "acdispat.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 %u, Bit offset %u\n",
     field_bit_length, field_bit_offset));

 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
     "Byte Length %u, Byte Offset %u, End Offset %u\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 %u end is within region\n",
       access_byte_width));

   ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
       "Field Start %u, Field End %u -- requires %u 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 %u\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 %u 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 %u\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 0x%X", access));

  return_UINT32(0);
 }

 if (obj_desc->common.type == 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 (values are: 1, 2, 4, 8) */

 obj_desc->common_field.access_byte_width = (u8)
     ACPI_DIV_8(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));

 return_ACPI_STATUS(AE_OK);
}

/*******************************************************************************
 *
 * FUNCTION:    acpi_ex_prep_field_value
 *
 * PARAMETERS:  info    - Contains all field creation info
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Construct an object of type union acpi_operand_object with a
 *              subtype of 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;
 union acpi_operand_object *second_desc = NULL;
 acpi_status status;
 u32 access_byte_width;
 u32 type;

 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 0x%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);

  /* Fields specific to generic_serial_bus fields */

  obj_desc->field.access_length = info->access_length;

  if (info->connection_node) {
   second_desc = info->connection_node->object;
   if (second_desc == NULL) {
    break;
   }
   if (!(second_desc->common.flags & AOPOBJ_DATA_VALID)) {
    status =
        acpi_ds_get_buffer_arguments(second_desc);
    if (ACPI_FAILURE(status)) {
     acpi_ut_delete_object_desc(obj_desc);
     return_ACPI_STATUS(status);
    }
   }

   obj_desc->field.resource_buffer =
       second_desc->buffer.pointer;
   obj_desc->field.resource_length =
       (u16)second_desc->buffer.length;
  } else if (info->resource_buffer) {
   obj_desc->field.resource_buffer = info->resource_buffer;
   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 ==
       ACPI_ADR_SPACE_EC)
      && (obj_desc->common_field.bit_length > 8)) {
   access_byte_width =
       ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.
       bit_length);

   /* Maximum byte width supported is 255 */

   if (access_byte_width < 256) {
    obj_desc->common_field.access_byte_width =
        (u8)access_byte_width;
   }
  }
  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));

  /*
 * Remember location in AML stream of the field unit
 * opcode and operands -- since the bank_value
 * operands must be evaluated.
 */
  second_desc = obj_desc->common.next_object;
  second_desc->extra.aml_start =
      ACPI_CAST_PTR(union acpi_parse_object,
      info->data_register_node)->named.data;
  second_desc->extra.aml_length =
      ACPI_CAST_PTR(union acpi_parse_object,
      info->data_register_node)->named.length;

  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);
}