[deliverable/linux.git] / drivers / acpi / tables / tbxfroot.c

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

/*
 * Copyright (C) 2000 - 2008, 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 <acpi/acpi.h>
#include <acpi/accommon.h>
#include <acpi/actables.h>

#define _COMPONENT          ACPI_TABLES
ACPI_MODULE_NAME("tbxfroot")

/* Local prototypes */
static u8 *acpi_tb_scan_memory_for_rsdp(u8 * start_address, u32 length);

static acpi_status acpi_tb_validate_rsdp(struct acpi_table_rsdp *rsdp);

/*******************************************************************************
 *
 * FUNCTION:    acpi_tb_validate_rsdp
 *
 * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
 *
 * RETURN:      Status
 *
 * DESCRIPTION: Validate the RSDP (ptr)
 *
 ******************************************************************************/

static acpi_status acpi_tb_validate_rsdp(struct acpi_table_rsdp *rsdp)
{
	ACPI_FUNCTION_ENTRY();

	/*
	 * 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_STRNCMP((char *)rsdp, ACPI_SIG_RSDP, sizeof(ACPI_SIG_RSDP) - 1)
	    != 0) {

		/* 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 1_mbyte 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 1_k 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 acpi_find_root_pointer(acpi_size *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 %8.8X for length %X",
			    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 1_k 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 %8.8X for length %X",
				    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 = 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 %8.8X for length %X",
			    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 = physical_address;
		return_ACPI_STATUS(AE_OK);
	}

	/* A valid RSDP was not found */

	ACPI_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
 *
 ******************************************************************************/
static 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);
}
Commit	Line	Data
1da177e4 LT	1	/******************************************************************************
	2	*
	3	* Module Name: tbxfroot - Find the root ACPI table (RSDT)
	4	*
	5	*****************************************************************************/
	6
	7	/*
75a44ce0	8	* Copyright (C) 2000 - 2008, Intel Corp.
1da177e4 LT	9	* All rights reserved.
	10	*
	11	* Redistribution and use in source and binary forms, with or without
	12	* modification, are permitted provided that the following conditions
	13	* are met:
	14	* 1. Redistributions of source code must retain the above copyright
	15	* notice, this list of conditions, and the following disclaimer,
	16	* without modification.
	17	* 2. Redistributions in binary form must reproduce at minimum a disclaimer
	18	* substantially similar to the "NO WARRANTY" disclaimer below
	19	* ("Disclaimer") and any redistribution must be conditioned upon
	20	* including a substantially similar Disclaimer requirement for further
	21	* binary redistribution.
	22	* 3. Neither the names of the above-listed copyright holders nor the names
	23	* of any contributors may be used to endorse or promote products derived
	24	* from this software without specific prior written permission.
	25	*
	26	* Alternatively, this software may be distributed under the terms of the
	27	* GNU General Public License ("GPL") version 2 as published by the Free
	28	* Software Foundation.
	29	*
	30	* NO WARRANTY
	31	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	32	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	33	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
	34	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	35	* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	36	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	37	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	38	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	39	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
	40	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	41	* POSSIBILITY OF SUCH DAMAGES.
	42	*/
	43
1da177e4	44	#include <acpi/acpi.h>
50df4d8b	45	#include <acpi/accommon.h>
1da177e4 LT	46	#include <acpi/actables.h>
1da177e4 LT	47
1da177e4	48	#define _COMPONENT ACPI_TABLES
4be44fcd	49	ACPI_MODULE_NAME("tbxfroot")
1da177e4	50
44f6c012	51	/* Local prototypes */
4be44fcd	52	static u8 acpi_tb_scan_memory_for_rsdp(u8 start_address, u32 length);
1da177e4	53
f3d2e786 BM	54	static acpi_status acpi_tb_validate_rsdp(struct acpi_table_rsdp *rsdp);
f3d2e786 BM	55
f9f4601f RM	56	/*******************************************************************************
	57	*
	58	* FUNCTION: acpi_tb_validate_rsdp
	59	*
f3d2e786	60	* PARAMETERS: Rsdp - Pointer to unvalidated RSDP
f9f4601f RM	61	*
	62	* RETURN: Status
	63	*
	64	* DESCRIPTION: Validate the RSDP (ptr)
	65	*
	66	******************************************************************************/
	67
f3d2e786	68	static acpi_status acpi_tb_validate_rsdp(struct acpi_table_rsdp *rsdp)
f9f4601f	69	{
4be44fcd	70	ACPI_FUNCTION_ENTRY();
f9f4601f RM	71
f9f4601f RM	72	/*
f3d2e786 BM	73	* The signature and checksum must both be correct
	74	*
	75	* Note: Sometimes there exists more than one RSDP in memory; the valid
	76	* RSDP has a valid checksum, all others have an invalid checksum.
f9f4601f	77	*/
f3d2e786 BM	78	if (ACPI_STRNCMP((char *)rsdp, ACPI_SIG_RSDP, sizeof(ACPI_SIG_RSDP) - 1)
f3d2e786 BM	79	!= 0) {
52fc0b02	80
f9f4601f RM	81	/* Nope, BAD Signature */
	82
	83	return (AE_BAD_SIGNATURE);
	84	}
	85
	86	/* Check the standard checksum */
	87
f3d2e786	88	if (acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) {
f9f4601f RM	89	return (AE_BAD_CHECKSUM);
	90	}
	91
	92	/* Check extended checksum if table version >= 2 */
	93
	94	if ((rsdp->revision >= 2) &&
f3d2e786	95	(acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) {
f9f4601f RM	96	return (AE_BAD_CHECKSUM);
	97	}
	98
	99	return (AE_OK);
	100	}
	101
1da177e4 LT	102	/*******************************************************************************
1da177e4 LT	103	*
239665a3	104	* FUNCTION: acpi_find_root_pointer
1da177e4	105	*
f3d2e786	106	* PARAMETERS: table_address - Where the table pointer is returned
1da177e4	107	*
f3d2e786	108	* RETURN: Status, RSDP physical address
1da177e4	109	*
f3d2e786 BM	110	* DESCRIPTION: Search lower 1_mbyte of memory for the root system descriptor
f3d2e786 BM	111	* pointer structure. If it is found, set *RSDP to point to it.
1da177e4	112	*
f3d2e786 BM	113	* NOTE1: The RSDP must be either in the first 1_k of the Extended
	114	* BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
	115	* Only a 32-bit physical address is necessary.
1da177e4	116	*
f3d2e786 BM	117	* NOTE2: This function is always available, regardless of the
f3d2e786 BM	118	* initialization state of the rest of ACPI.
1da177e4 LT	119	*
	120	******************************************************************************/
	121
67a119f9	122	acpi_status acpi_find_root_pointer(acpi_size *table_address)
1da177e4	123	{
f3d2e786 BM	124	u8 *table_ptr;
	125	u8 *mem_rover;
	126	u32 physical_address;
1da177e4	127
f3d2e786	128	ACPI_FUNCTION_TRACE(acpi_find_root_pointer);
1da177e4	129
f3d2e786	130	/* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
1da177e4	131
f3d2e786 BM	132	table_ptr = acpi_os_map_memory((acpi_physical_address)
	133	ACPI_EBDA_PTR_LOCATION,
	134	ACPI_EBDA_PTR_LENGTH);
	135	if (!table_ptr) {
	136	ACPI_ERROR((AE_INFO,
	137	"Could not map memory at %8.8X for length %X",
	138	ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
1da177e4	139
4be44fcd	140	return_ACPI_STATUS(AE_NO_MEMORY);
1da177e4 LT	141	}
1da177e4 LT	142
f3d2e786	143	ACPI_MOVE_16_TO_32(&physical_address, table_ptr);
1da177e4	144
f3d2e786	145	/* Convert segment part to physical address */
1da177e4	146
f3d2e786 BM	147	physical_address <<= 4;
f3d2e786 BM	148	acpi_os_unmap_memory(table_ptr, ACPI_EBDA_PTR_LENGTH);
1da177e4	149
f3d2e786	150	/* EBDA present? */
1da177e4	151
f3d2e786	152	if (physical_address > 0x400) {
73459f73	153	/*
f3d2e786 BM	154	* 1b) Search EBDA paragraphs (EBDA is required to be a
f3d2e786 BM	155	* minimum of 1_k length)
73459f73	156	*/
67a119f9	157	table_ptr = acpi_os_map_memory((acpi_physical_address)
f3d2e786 BM	158	physical_address,
	159	ACPI_EBDA_WINDOW_SIZE);
	160	if (!table_ptr) {
	161	ACPI_ERROR((AE_INFO,
	162	"Could not map memory at %8.8X for length %X",
	163	physical_address, ACPI_EBDA_WINDOW_SIZE));
1da177e4	164
f3d2e786	165	return_ACPI_STATUS(AE_NO_MEMORY);
1da177e4 LT	166	}
1da177e4 LT	167
f3d2e786 BM	168	mem_rover =
	169	acpi_tb_scan_memory_for_rsdp(table_ptr,
	170	ACPI_EBDA_WINDOW_SIZE);
	171	acpi_os_unmap_memory(table_ptr, ACPI_EBDA_WINDOW_SIZE);
1da177e4	172
f3d2e786	173	if (mem_rover) {
52fc0b02	174
f3d2e786	175	/* Return the physical address */
1da177e4	176
f3d2e786 BM	177	physical_address +=
f3d2e786 BM	178	(u32) ACPI_PTR_DIFF(mem_rover, table_ptr);
1da177e4	179
f3d2e786 BM	180	*table_address = physical_address;
f3d2e786 BM	181	return_ACPI_STATUS(AE_OK);
1da177e4 LT	182	}
	183	}
	184
f3d2e786 BM	185	/*
	186	* 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
	187	*/
	188	table_ptr = acpi_os_map_memory((acpi_physical_address)
	189	ACPI_HI_RSDP_WINDOW_BASE,
	190	ACPI_HI_RSDP_WINDOW_SIZE);
1da177e4	191
f3d2e786 BM	192	if (!table_ptr) {
	193	ACPI_ERROR((AE_INFO,
	194	"Could not map memory at %8.8X for length %X",
	195	ACPI_HI_RSDP_WINDOW_BASE,
	196	ACPI_HI_RSDP_WINDOW_SIZE));
1da177e4	197
f3d2e786	198	return_ACPI_STATUS(AE_NO_MEMORY);
88ac00f5	199	}
1da177e4	200
f3d2e786 BM	201	mem_rover =
	202	acpi_tb_scan_memory_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);
	203	acpi_os_unmap_memory(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE);
1da177e4	204
f3d2e786	205	if (mem_rover) {
1da177e4	206
f3d2e786	207	/* Return the physical address */
1da177e4	208
f3d2e786 BM	209	physical_address = (u32)
	210	(ACPI_HI_RSDP_WINDOW_BASE +
	211	ACPI_PTR_DIFF(mem_rover, table_ptr));
1da177e4	212
f3d2e786 BM	213	*table_address = physical_address;
f3d2e786 BM	214	return_ACPI_STATUS(AE_OK);
1da177e4 LT	215	}
1da177e4 LT	216
f3d2e786 BM	217	/* A valid RSDP was not found */
	218
	219	ACPI_ERROR((AE_INFO, "A valid RSDP was not found"));
	220	return_ACPI_STATUS(AE_NOT_FOUND);
1da177e4 LT	221	}
1da177e4 LT	222
1da177e4 LT	223	/*******************************************************************************
	224	*
	225	* FUNCTION: acpi_tb_scan_memory_for_rsdp
	226	*
	227	* PARAMETERS: start_address - Starting pointer for search
	228	* Length - Maximum length to search
	229	*
	230	* RETURN: Pointer to the RSDP if found, otherwise NULL.
	231	*
	232	* DESCRIPTION: Search a block of memory for the RSDP signature
	233	*
	234	******************************************************************************/
4be44fcd	235	static u8 acpi_tb_scan_memory_for_rsdp(u8 start_address, u32 length)
1da177e4	236	{
4be44fcd LB	237	acpi_status status;
	238	u8 *mem_rover;
	239	u8 *end_address;
1da177e4	240
b229cf92	241	ACPI_FUNCTION_TRACE(tb_scan_memory_for_rsdp);
1da177e4 LT	242
	243	end_address = start_address + length;
	244
	245	/* Search from given start address for the requested length */
	246
	247	for (mem_rover = start_address; mem_rover < end_address;
4be44fcd	248	mem_rover += ACPI_RSDP_SCAN_STEP) {
52fc0b02	249
f9f4601f	250	/* The RSDP signature and checksum must both be correct */
1da177e4	251
4be44fcd LB	252	status =
4be44fcd LB	253	acpi_tb_validate_rsdp(ACPI_CAST_PTR
f3d2e786	254	(struct acpi_table_rsdp, mem_rover));
4be44fcd	255	if (ACPI_SUCCESS(status)) {
52fc0b02	256
f9f4601f	257	/* Sig and checksum valid, we have found a real RSDP */
1da177e4	258
4be44fcd LB	259	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	260	"RSDP located at physical address %p\n",
	261	mem_rover));
	262	return_PTR(mem_rover);
1da177e4 LT	263	}
1da177e4 LT	264
f9f4601f	265	/* No sig match or bad checksum, keep searching */
1da177e4 LT	266	}
	267
	268	/* Searched entire block, no RSDP was found */
	269
4be44fcd LB	270	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	271	"Searched entire block from %p, valid RSDP was not found\n",
	272	start_address));
	273	return_PTR(NULL);
1da177e4	274	}