1/******************************************************************************
2 *
3 * Module Name: tbxfroot - Find the root ACPI table (RSDT)
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2013, Intel Corp.
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
44#define __TBXFROOT_C__
45
46#include <contrib/dev/acpica/include/acpi.h>
47#include <contrib/dev/acpica/include/accommon.h>
48#include <contrib/dev/acpica/include/actables.h>
49
50
51#define _COMPONENT          ACPI_TABLES
52        ACPI_MODULE_NAME    ("tbxfroot")
53
54
55/*******************************************************************************
56 *
57 * FUNCTION:    AcpiTbValidateRsdp
58 *
59 * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
60 *
61 * RETURN:      Status
62 *
63 * DESCRIPTION: Validate the RSDP (ptr)
64 *
65 ******************************************************************************/
66
67ACPI_STATUS
68AcpiTbValidateRsdp (
69    ACPI_TABLE_RSDP         *Rsdp)
70{
71
72    /*
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.
77     */
78    if (!ACPI_VALIDATE_RSDP_SIG (Rsdp->Signature))
79    {
80        /* Nope, BAD Signature */
81
82        return (AE_BAD_SIGNATURE);
83    }
84
85    /* Check the standard checksum */
86
87    if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
88    {
89        return (AE_BAD_CHECKSUM);
90    }
91
92    /* Check extended checksum if table version >= 2 */
93
94    if ((Rsdp->Revision >= 2) &&
95        (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
96    {
97        return (AE_BAD_CHECKSUM);
98    }
99
100    return (AE_OK);
101}
102
103
104/*******************************************************************************
105 *
106 * FUNCTION:    AcpiFindRootPointer
107 *
108 * PARAMETERS:  TableAddress            - Where the table pointer is returned
109 *
110 * RETURN:      Status, RSDP physical address
111 *
112 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
113 *              pointer structure. If it is found, set *RSDP to point to it.
114 *
115 * NOTE1:       The RSDP must be either in the first 1K of the Extended
116 *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
117 *              Only a 32-bit physical address is necessary.
118 *
119 * NOTE2:       This function is always available, regardless of the
120 *              initialization state of the rest of ACPI.
121 *
122 ******************************************************************************/
123
124ACPI_STATUS
125AcpiFindRootPointer (
126    ACPI_SIZE               *TableAddress)
127{
128    UINT8                   *TablePtr;
129    UINT8                   *MemRover;
130    UINT32                  PhysicalAddress;
131
132
133    ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
134
135
136    /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
137
138    TablePtr = AcpiOsMapMemory (
139                (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
140                ACPI_EBDA_PTR_LENGTH);
141    if (!TablePtr)
142    {
143        ACPI_ERROR ((AE_INFO,
144            "Could not map memory at 0x%8.8X for length %u",
145            ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
146
147        return_ACPI_STATUS (AE_NO_MEMORY);
148    }
149
150    ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
151
152    /* Convert segment part to physical address */
153
154    PhysicalAddress <<= 4;
155    AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
156
157    /* EBDA present? */
158
159    if (PhysicalAddress > 0x400)
160    {
161        /*
162         * 1b) Search EBDA paragraphs (EBDA is required to be a
163         *     minimum of 1K length)
164         */
165        TablePtr = AcpiOsMapMemory (
166                    (ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
167                    ACPI_EBDA_WINDOW_SIZE);
168        if (!TablePtr)
169        {
170            ACPI_ERROR ((AE_INFO,
171                "Could not map memory at 0x%8.8X for length %u",
172                PhysicalAddress, ACPI_EBDA_WINDOW_SIZE));
173
174            return_ACPI_STATUS (AE_NO_MEMORY);
175        }
176
177        MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_EBDA_WINDOW_SIZE);
178        AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE);
179
180        if (MemRover)
181        {
182            /* Return the physical address */
183
184            PhysicalAddress += (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
185
186            *TableAddress = PhysicalAddress;
187            return_ACPI_STATUS (AE_OK);
188        }
189    }
190
191    /*
192     * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
193     */
194    TablePtr = AcpiOsMapMemory (
195                (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
196                ACPI_HI_RSDP_WINDOW_SIZE);
197
198    if (!TablePtr)
199    {
200        ACPI_ERROR ((AE_INFO,
201            "Could not map memory at 0x%8.8X for length %u",
202            ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
203
204        return_ACPI_STATUS (AE_NO_MEMORY);
205    }
206
207    MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
208    AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
209
210    if (MemRover)
211    {
212        /* Return the physical address */
213
214        PhysicalAddress = (UINT32)
215            (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
216
217        *TableAddress = PhysicalAddress;
218        return_ACPI_STATUS (AE_OK);
219    }
220
221    /* A valid RSDP was not found */
222
223    ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found"));
224    return_ACPI_STATUS (AE_NOT_FOUND);
225}
226
227ACPI_EXPORT_SYMBOL (AcpiFindRootPointer)
228
229
230/*******************************************************************************
231 *
232 * FUNCTION:    AcpiTbScanMemoryForRsdp
233 *
234 * PARAMETERS:  StartAddress        - Starting pointer for search
235 *              Length              - Maximum length to search
236 *
237 * RETURN:      Pointer to the RSDP if found, otherwise NULL.
238 *
239 * DESCRIPTION: Search a block of memory for the RSDP signature
240 *
241 ******************************************************************************/
242
243UINT8 *
244AcpiTbScanMemoryForRsdp (
245    UINT8                   *StartAddress,
246    UINT32                  Length)
247{
248    ACPI_STATUS             Status;
249    UINT8                   *MemRover;
250    UINT8                   *EndAddress;
251
252
253    ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
254
255
256    EndAddress = StartAddress + Length;
257
258    /* Search from given start address for the requested length */
259
260    for (MemRover = StartAddress; MemRover < EndAddress;
261         MemRover += ACPI_RSDP_SCAN_STEP)
262    {
263        /* The RSDP signature and checksum must both be correct */
264
265        Status = AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
266        if (ACPI_SUCCESS (Status))
267        {
268            /* Sig and checksum valid, we have found a real RSDP */
269
270            ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
271                "RSDP located at physical address %p\n", MemRover));
272            return_PTR (MemRover);
273        }
274
275        /* No sig match or bad checksum, keep searching */
276    }
277
278    /* Searched entire block, no RSDP was found */
279
280    ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
281        "Searched entire block from %p, valid RSDP was not found\n",
282        StartAddress));
283    return_PTR (NULL);
284}
285