Subversion Repositories Kolibri OS

/******************************************************************************

 *

 * Module Name: tbxfroot - Find the root ACPI table (RSDT)

 *

 *****************************************************************************/

/*

 * Copyright (C) 2000 - 2015, Intel Corp.

 * 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 

#include "accommon.h"

#include "actables.h"

#define _COMPONENT          ACPI_TABLES

ACPI_MODULE_NAME("tbxfroot")

/*******************************************************************************

 *

 * FUNCTION:    acpi_tb_get_rsdp_length

 *

 * PARAMETERS:  rsdp                - Pointer to RSDP

 *

 * RETURN:      Table length

 *

 * DESCRIPTION: Get the length of the RSDP

 *

 ******************************************************************************/

u32 acpi_tb_get_rsdp_length(struct acpi_table_rsdp *rsdp)

{

	if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature)) {

		/* BAD Signature */

		return (0);

	}

	/* "Length" field is available if table version >= 2 */

	if (rsdp->revision >= 2) {

		return (rsdp->length);

	} else {

		return (ACPI_RSDP_CHECKSUM_LENGTH);

	}

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_tb_validate_rsdp

 *

 * PARAMETERS:  rsdp                - Pointer to unvalidated RSDP

 *

 * RETURN:      Status

 *

 * DESCRIPTION: Validate the RSDP (ptr)

 *

 ******************************************************************************/

acpi_status acpi_tb_validate_rsdp(struct acpi_table_rsdp * rsdp)

{

	/*

	 * The signature and checksum must both be correct

	 *

	 * Note: Sometimes there exists more than one RSDP in memory; the valid

	 * RSDP has a valid checksum, all others have an invalid checksum.

	 */

	if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature)) {

		/* Nope, BAD Signature */

		return (AE_BAD_SIGNATURE);

	}

	/* Check the standard checksum */

	if (acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) {

		return (AE_BAD_CHECKSUM);

	}

	/* Check extended checksum if table version >= 2 */

	if ((rsdp->revision >= 2) &&

	    (acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) {

		return (AE_BAD_CHECKSUM);

	}

	return (AE_OK);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_find_root_pointer

 *

 * PARAMETERS:  table_address           - Where the table pointer is returned

 *

 * RETURN:      Status, RSDP physical address

 *

 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor

 *              pointer structure. If it is found, set *RSDP to point to it.

 *

 * NOTE1:       The RSDP must be either in the first 1K of the Extended

 *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)

 *              Only a 32-bit physical address is necessary.

 *

 * NOTE2:       This function is always available, regardless of the

 *              initialization state of the rest of ACPI.

 *

 ******************************************************************************/

acpi_status __init acpi_find_root_pointer(acpi_physical_address * table_address)

{

	u8 *table_ptr;

	u8 *mem_rover;

	u32 physical_address;

	ACPI_FUNCTION_TRACE(acpi_find_root_pointer);

	/* 1a) Get the location of the Extended BIOS Data Area (EBDA) */

	table_ptr = acpi_os_map_memory((acpi_physical_address)

				       ACPI_EBDA_PTR_LOCATION,

				       ACPI_EBDA_PTR_LENGTH);

	if (!table_ptr) {

		ACPI_ERROR((AE_INFO,

			    "Could not map memory at 0x%8.8X for length %u",

			    ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));

		return_ACPI_STATUS(AE_NO_MEMORY);

	}

	ACPI_MOVE_16_TO_32(&physical_address, table_ptr);

	/* Convert segment part to physical address */

	physical_address <<= 4;

	acpi_os_unmap_memory(table_ptr, ACPI_EBDA_PTR_LENGTH);

	/* EBDA present? */

	if (physical_address > 0x400) {

		/*

		 * 1b) Search EBDA paragraphs (EBDA is required to be a

		 *     minimum of 1K length)

		 */

		table_ptr = acpi_os_map_memory((acpi_physical_address)

					       physical_address,

					       ACPI_EBDA_WINDOW_SIZE);

		if (!table_ptr) {

			ACPI_ERROR((AE_INFO,

				    "Could not map memory at 0x%8.8X for length %u",

				    physical_address, ACPI_EBDA_WINDOW_SIZE));

			return_ACPI_STATUS(AE_NO_MEMORY);

		}

		mem_rover =

		    acpi_tb_scan_memory_for_rsdp(table_ptr,

						 ACPI_EBDA_WINDOW_SIZE);

		acpi_os_unmap_memory(table_ptr, ACPI_EBDA_WINDOW_SIZE);

		if (mem_rover) {

			/* Return the physical address */

			physical_address +=

			    (u32) ACPI_PTR_DIFF(mem_rover, table_ptr);

			*table_address =

			    (acpi_physical_address) physical_address;

			return_ACPI_STATUS(AE_OK);

		}

	}

	/*

	 * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh

	 */

	table_ptr = acpi_os_map_memory((acpi_physical_address)

				       ACPI_HI_RSDP_WINDOW_BASE,

				       ACPI_HI_RSDP_WINDOW_SIZE);

	if (!table_ptr) {

		ACPI_ERROR((AE_INFO,

			    "Could not map memory at 0x%8.8X for length %u",

			    ACPI_HI_RSDP_WINDOW_BASE,

			    ACPI_HI_RSDP_WINDOW_SIZE));

		return_ACPI_STATUS(AE_NO_MEMORY);

	}

	mem_rover =

	    acpi_tb_scan_memory_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);

	acpi_os_unmap_memory(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);

	if (mem_rover) {

		/* Return the physical address */

		physical_address = (u32)

		    (ACPI_HI_RSDP_WINDOW_BASE +

		     ACPI_PTR_DIFF(mem_rover, table_ptr));

		*table_address = (acpi_physical_address) physical_address;

		return_ACPI_STATUS(AE_OK);

	}

	/* A valid RSDP was not found */

	ACPI_BIOS_ERROR((AE_INFO, "A valid RSDP was not found"));

	return_ACPI_STATUS(AE_NOT_FOUND);

}

/*******************************************************************************

 *

 * FUNCTION:    acpi_tb_scan_memory_for_rsdp

 *

 * PARAMETERS:  start_address       - Starting pointer for search

 *              length              - Maximum length to search

 *

 * RETURN:      Pointer to the RSDP if found, otherwise NULL.

 *

 * DESCRIPTION: Search a block of memory for the RSDP signature

 *

 ******************************************************************************/

u8 *acpi_tb_scan_memory_for_rsdp(u8 *start_address, u32 length)

{

	acpi_status status;

	u8 *mem_rover;

	u8 *end_address;

	ACPI_FUNCTION_TRACE(tb_scan_memory_for_rsdp);

	end_address = start_address + length;

	/* Search from given start address for the requested length */

	for (mem_rover = start_address; mem_rover < end_address;

	     mem_rover += ACPI_RSDP_SCAN_STEP) {

		/* The RSDP signature and checksum must both be correct */

		status =

		    acpi_tb_validate_rsdp(ACPI_CAST_PTR

					  (struct acpi_table_rsdp, mem_rover));

		if (ACPI_SUCCESS(status)) {

			/* Sig and checksum valid, we have found a real RSDP */

			ACPI_DEBUG_PRINT((ACPI_DB_INFO,

					  "RSDP located at physical address %p\n",

					  mem_rover));

			return_PTR(mem_rover);

		}

		/* No sig match or bad checksum, keep searching */

	}

	/* Searched entire block, no RSDP was found */

	ACPI_DEBUG_PRINT((ACPI_DB_INFO,

			  "Searched entire block from %p, valid RSDP was not found\n",

			  start_address));

	return_PTR(NULL);

}