linux/drivers/acpi/acpica/tbutils.c

// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/******************************************************************************
 *
 * Module Name: tbutils - ACPI Table utilities
 *
 * Copyright (C) 2000 - 2023, Intel Corp.
 *
 *****************************************************************************/

#include <acpi/acpi.h>
#include "accommon.h"
#include "actables.h"

#define _COMPONENT …
ACPI_MODULE_NAME("tbutils")

/* Local prototypes */
static acpi_physical_address
acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size);

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_initialize_facs
 *
 * PARAMETERS:  None
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Create a permanent mapping for the FADT and save it in a global
 *              for accessing the Global Lock and Firmware Waking Vector
 *
 ******************************************************************************/

acpi_status acpi_tb_initialize_facs(void)
{ … }

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_check_dsdt_header
 *
 * PARAMETERS:  None
 *
 * RETURN:      None
 *
 * DESCRIPTION: Quick compare to check validity of the DSDT. This will detect
 *              if the DSDT has been replaced from outside the OS and/or if
 *              the DSDT header has been corrupted.
 *
 ******************************************************************************/

void acpi_tb_check_dsdt_header(void)
{ … }

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_copy_dsdt
 *
 * PARAMETERS:  table_index         - Index of installed table to copy
 *
 * RETURN:      The copied DSDT
 *
 * DESCRIPTION: Implements a subsystem option to copy the DSDT to local memory.
 *              Some very bad BIOSs are known to either corrupt the DSDT or
 *              install a new, bad DSDT. This copy works around the problem.
 *
 ******************************************************************************/

struct acpi_table_header *acpi_tb_copy_dsdt(u32 table_index)
{ … }

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_get_root_table_entry
 *
 * PARAMETERS:  table_entry         - Pointer to the RSDT/XSDT table entry
 *              table_entry_size    - sizeof 32 or 64 (RSDT or XSDT)
 *
 * RETURN:      Physical address extracted from the root table
 *
 * DESCRIPTION: Get one root table entry. Handles 32-bit and 64-bit cases on
 *              both 32-bit and 64-bit platforms
 *
 * NOTE:        acpi_physical_address is 32-bit on 32-bit platforms, 64-bit on
 *              64-bit platforms.
 *
 ******************************************************************************/

static acpi_physical_address
acpi_tb_get_root_table_entry(u8 *table_entry, u32 table_entry_size)
{ … }

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_parse_root_table
 *
 * PARAMETERS:  rsdp_address        - Pointer to the RSDP
 *
 * RETURN:      Status
 *
 * DESCRIPTION: This function is called to parse the Root System Description
 *              Table (RSDT or XSDT)
 *
 * NOTE:        Tables are mapped (not copied) for efficiency. The FACS must
 *              be mapped and cannot be copied because it contains the actual
 *              memory location of the ACPI Global Lock.
 *
 ******************************************************************************/

acpi_status ACPI_INIT_FUNCTION
acpi_tb_parse_root_table(acpi_physical_address rsdp_address)
{ … }

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_get_table
 *
 * PARAMETERS:  table_desc          - Table descriptor
 *              out_table           - Where the pointer to the table is returned
 *
 * RETURN:      Status and pointer to the requested table
 *
 * DESCRIPTION: Increase a reference to a table descriptor and return the
 *              validated table pointer.
 *              If the table descriptor is an entry of the root table list,
 *              this API must be invoked with ACPI_MTX_TABLES acquired.
 *
 ******************************************************************************/

acpi_status
acpi_tb_get_table(struct acpi_table_desc *table_desc,
		  struct acpi_table_header **out_table)
{ … }

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_put_table
 *
 * PARAMETERS:  table_desc          - Table descriptor
 *
 * RETURN:      None
 *
 * DESCRIPTION: Decrease a reference to a table descriptor and release the
 *              validated table pointer if no references.
 *              If the table descriptor is an entry of the root table list,
 *              this API must be invoked with ACPI_MTX_TABLES acquired.
 *
 ******************************************************************************/

void acpi_tb_put_table(struct acpi_table_desc *table_desc)
{ … }