// 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);
}