tbxfroot.c revision 70243 
1/******************************************************************************
2 *
3 * Module Name: tbxfroot - Find the root ACPI table (RSDT)
4 *              $Revision: 34 $
5 *
6 *****************************************************************************/
7
8/******************************************************************************
9 *
10 * 1. Copyright Notice
11 *
12 * Some or all of this work - Copyright (c) 1999, 2000, Intel Corp.
13 * All rights reserved.
14 *
15 * 2. License
16 *
17 * 2.1. This is your license from Intel Corp. under its intellectual property
18 * rights.  You may have additional license terms from the party that provided
19 * you this software, covering your right to use that party's intellectual
20 * property rights.
21 *
22 * 2.2. Intel grants, free of charge, to any person ("Licensee") obtaining a
23 * copy of the source code appearing in this file ("Covered Code") an
24 * irrevocable, perpetual, worldwide license under Intel's copyrights in the
25 * base code distributed originally by Intel ("Original Intel Code") to copy,
26 * make derivatives, distribute, use and display any portion of the Covered
27 * Code in any form, with the right to sublicense such rights; and
28 *
29 * 2.3. Intel grants Licensee a non-exclusive and non-transferable patent
30 * license (with the right to sublicense), under only those claims of Intel
31 * patents that are infringed by the Original Intel Code, to make, use, sell,
32 * offer to sell, and import the Covered Code and derivative works thereof
33 * solely to the minimum extent necessary to exercise the above copyright
34 * license, and in no event shall the patent license extend to any additions
35 * to or modifications of the Original Intel Code.  No other license or right
36 * is granted directly or by implication, estoppel or otherwise;
37 *
38 * The above copyright and patent license is granted only if the following
39 * conditions are met:
40 *
41 * 3. Conditions
42 *
43 * 3.1. Redistribution of Source with Rights to Further Distribute Source.
44 * Redistribution of source code of any substantial portion of the Covered
45 * Code or modification with rights to further distribute source must include
46 * the above Copyright Notice, the above License, this list of Conditions,
47 * and the following Disclaimer and Export Compliance provision.  In addition,
48 * Licensee must cause all Covered Code to which Licensee contributes to
49 * contain a file documenting the changes Licensee made to create that Covered
50 * Code and the date of any change.  Licensee must include in that file the
51 * documentation of any changes made by any predecessor Licensee.  Licensee
52 * must include a prominent statement that the modification is derived,
53 * directly or indirectly, from Original Intel Code.
54 *
55 * 3.2. Redistribution of Source with no Rights to Further Distribute Source.
56 * Redistribution of source code of any substantial portion of the Covered
57 * Code or modification without rights to further distribute source must
58 * include the following Disclaimer and Export Compliance provision in the
59 * documentation and/or other materials provided with distribution.  In
60 * addition, Licensee may not authorize further sublicense of source of any
61 * portion of the Covered Code, and must include terms to the effect that the
62 * license from Licensee to its licensee is limited to the intellectual
63 * property embodied in the software Licensee provides to its licensee, and
64 * not to intellectual property embodied in modifications its licensee may
65 * make.
66 *
67 * 3.3. Redistribution of Executable. Redistribution in executable form of any
68 * substantial portion of the Covered Code or modification must reproduce the
69 * above Copyright Notice, and the following Disclaimer and Export Compliance
70 * provision in the documentation and/or other materials provided with the
71 * distribution.
72 *
73 * 3.4. Intel retains all right, title, and interest in and to the Original
74 * Intel Code.
75 *
76 * 3.5. Neither the name Intel nor any other trademark owned or controlled by
77 * Intel shall be used in advertising or otherwise to promote the sale, use or
78 * other dealings in products derived from or relating to the Covered Code
79 * without prior written authorization from Intel.
80 *
81 * 4. Disclaimer and Export Compliance
82 *
83 * 4.1. INTEL MAKES NO WARRANTY OF ANY KIND REGARDING ANY SOFTWARE PROVIDED
84 * HERE.  ANY SOFTWARE ORIGINATING FROM INTEL OR DERIVED FROM INTEL SOFTWARE
85 * IS PROVIDED "AS IS," AND INTEL WILL NOT PROVIDE ANY SUPPORT,  ASSISTANCE,
86 * INSTALLATION, TRAINING OR OTHER SERVICES.  INTEL WILL NOT PROVIDE ANY
87 * UPDATES, ENHANCEMENTS OR EXTENSIONS.  INTEL SPECIFICALLY DISCLAIMS ANY
88 * IMPLIED WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT AND FITNESS FOR A
89 * PARTICULAR PURPOSE.
90 *
91 * 4.2. IN NO EVENT SHALL INTEL HAVE ANY LIABILITY TO LICENSEE, ITS LICENSEES
92 * OR ANY OTHER THIRD PARTY, FOR ANY LOST PROFITS, LOST DATA, LOSS OF USE OR
93 * COSTS OF PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY INDIRECT,
94 * SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, UNDER ANY
95 * CAUSE OF ACTION OR THEORY OF LIABILITY, AND IRRESPECTIVE OF WHETHER INTEL
96 * HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.  THESE LIMITATIONS
97 * SHALL APPLY NOTWITHSTANDING THE FAILURE OF THE ESSENTIAL PURPOSE OF ANY
98 * LIMITED REMEDY.
99 *
100 * 4.3. Licensee shall not export, either directly or indirectly, any of this
101 * software or system incorporating such software without first obtaining any
102 * required license or other approval from the U. S. Department of Commerce or
103 * any other agency or department of the United States Government.  In the
104 * event Licensee exports any such software from the United States or
105 * re-exports any such software from a foreign destination, Licensee shall
106 * ensure that the distribution and export/re-export of the software is in
107 * compliance with all laws, regulations, orders, or other restrictions of the
108 * U.S. Export Administration Regulations. Licensee agrees that neither it nor
109 * any of its subsidiaries will export/re-export any technical data, process,
110 * software, or service, directly or indirectly, to any country for which the
111 * United States government or any agency thereof requires an export license,
112 * other governmental approval, or letter of assurance, without first obtaining
113 * such license, approval or letter.
114 *
115 *****************************************************************************/
116
117#define __TBXFROOT_C__
118
119#include "acpi.h"
120#include "achware.h"
121#include "actables.h"
122
123
124#define _COMPONENT          TABLE_MANAGER
125        MODULE_NAME         ("tbxfroot")
126
127#define RSDP_CHECKSUM_LENGTH 20
128
129
130/*******************************************************************************
131 *
132 * FUNCTION:    AcpiFindRootPointer
133 *
134 * PARAMETERS:  **RsdpPhysicalAddress       - Where to place the RSDP address
135 *
136 * RETURN:      Status, Physical address of the RSDP
137 *
138 * DESCRIPTION: Find the RSDP
139 *
140 ******************************************************************************/
141
142ACPI_STATUS
143AcpiFindRootPointer (
144    ACPI_PHYSICAL_ADDRESS   *RsdpPhysicalAddress)
145{
146    ACPI_TABLE_DESC         TableInfo;
147    ACPI_STATUS             Status;
148
149
150    FUNCTION_TRACE ("AcpiFindRootPointer");
151
152
153    /* Get the RSDP */
154
155    Status = AcpiTbFindRsdp (&TableInfo);
156    if (ACPI_FAILURE (Status))
157    {
158        DEBUG_PRINT (ACPI_ERROR, ("RSDP structure not found\n"));
159        return_ACPI_STATUS (AE_NO_ACPI_TABLES);
160    }
161
162    *RsdpPhysicalAddress = TableInfo.PhysicalAddress;
163
164    return_ACPI_STATUS (AE_OK);
165}
166
167
168/*******************************************************************************
169 *
170 * FUNCTION:    AcpiTbScanMemoryForRsdp
171 *
172 * PARAMETERS:  StartAddress        - Starting pointer for search
173 *              Length              - Maximum length to search
174 *
175 * RETURN:      Pointer to the RSDP if found, otherwise NULL.
176 *
177 * DESCRIPTION: Search a block of memory for the RSDP signature
178 *
179 ******************************************************************************/
180
181UINT8 *
182AcpiTbScanMemoryForRsdp (
183    UINT8                   *StartAddress,
184    UINT32                  Length)
185{
186    UINT32                  Offset;
187    UINT8                   *MemRover;
188
189
190    FUNCTION_TRACE ("TbScanMemoryForRsdp");
191
192    /* Search from given start addr for the requested length  */
193
194    for (Offset = 0, MemRover = StartAddress;
195         Offset < Length;
196         Offset += RSDP_SCAN_STEP, MemRover += RSDP_SCAN_STEP)
197    {
198
199        /* The signature and checksum must both be correct */
200
201        if (STRNCMP ((NATIVE_CHAR *) MemRover,
202                RSDP_SIG, sizeof (RSDP_SIG)-1) == 0 &&
203            AcpiTbChecksum (MemRover, RSDP_CHECKSUM_LENGTH) == 0)
204        {
205            /* If so, we have found the RSDP */
206
207            return_PTR (MemRover);
208        }
209    }
210
211    /* Searched entire block, no RSDP was found */
212
213    return_PTR (NULL);
214}
215
216
217/*******************************************************************************
218 *
219 * FUNCTION:    AcpiTbFindRsdp
220 *
221 * PARAMETERS:  *BufferPtr              - If == NULL, read data from buffer
222 *                                        rather than searching memory
223 *              *TableInfo              - Where the table info is returned
224 *
225 * RETURN:      Status
226 *
227 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
228 *              pointer structure.  If it is found, set *RSDP to point to it.
229 *
230 *              NOTE: The RSDP must be either in the first 1K of the Extended
231 *              BIOS Data Area or between E0000 and FFFFF (ACPI 1.0 section
232 *              5.2.2; assertion #421).
233 *
234 ******************************************************************************/
235
236ACPI_STATUS
237AcpiTbFindRsdp (
238    ACPI_TABLE_DESC         *TableInfo)
239{
240    UINT8                   *TablePtr;
241    UINT8                   *MemRover;
242    UINT64                  PhysAddr;
243    ACPI_STATUS             Status = AE_OK;
244
245
246    FUNCTION_TRACE ("TbFindRsdp");
247
248
249    /*
250     * Search memory for RSDP.  First map low physical memory.
251     */
252
253    Status = AcpiOsMapMemory (LO_RSDP_WINDOW_BASE, LO_RSDP_WINDOW_SIZE,
254                                (void **)&TablePtr);
255
256    if (ACPI_FAILURE (Status))
257    {
258        return_ACPI_STATUS (Status);
259    }
260
261    /*
262     * 1) Search EBDA (low memory) paragraphs
263     */
264
265    MemRover = AcpiTbScanMemoryForRsdp (TablePtr, LO_RSDP_WINDOW_SIZE);
266
267    /* This mapping is no longer needed */
268
269    AcpiOsUnmapMemory (TablePtr, LO_RSDP_WINDOW_SIZE);
270
271    if (MemRover)
272    {
273        /* Found it, return the physical address */
274
275        PhysAddr = LO_RSDP_WINDOW_BASE;
276        PhysAddr += (MemRover - TablePtr);
277
278        TableInfo->PhysicalAddress = PhysAddr;
279
280        return_ACPI_STATUS (AE_OK);
281    }
282
283
284    /*
285     * 2) Search upper memory: 16-byte boundaries in E0000h-F0000h
286     */
287
288    Status = AcpiOsMapMemory (HI_RSDP_WINDOW_BASE, HI_RSDP_WINDOW_SIZE,
289                                (void **)&TablePtr);
290
291    if (ACPI_FAILURE (Status))
292    {
293        return_ACPI_STATUS (Status);
294    }
295
296    MemRover = AcpiTbScanMemoryForRsdp (TablePtr, HI_RSDP_WINDOW_SIZE);
297
298    /* This mapping is no longer needed */
299
300    AcpiOsUnmapMemory (TablePtr, HI_RSDP_WINDOW_SIZE);
301
302    if (MemRover)
303    {
304        /* Found it, return the physical address */
305
306        PhysAddr = HI_RSDP_WINDOW_BASE;
307        PhysAddr += (MemRover - TablePtr);
308
309        TableInfo->PhysicalAddress = PhysAddr;
310
311        return_ACPI_STATUS (AE_OK);
312    }
313
314
315    /* RSDP signature was not found */
316
317    return_ACPI_STATUS (AE_NOT_FOUND);
318}
319
320
321