tbxfroot.c revision 238381 
1/******************************************************************************
2 *
3 * Module Name: tbxfroot - Find the root ACPI table (RSDT)
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2012, 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/* Local prototypes */
55
56static UINT8 *
57AcpiTbScanMemoryForRsdp (
58    UINT8                   *StartAddress,
59    UINT32                  Length);
60
61static ACPI_STATUS
62AcpiTbValidateRsdp (
63    ACPI_TABLE_RSDP         *Rsdp);
64
65
66/*******************************************************************************
67 *
68 * FUNCTION:    AcpiTbValidateRsdp
69 *
70 * PARAMETERS:  Rsdp                - Pointer to unvalidated RSDP
71 *
72 * RETURN:      Status
73 *
74 * DESCRIPTION: Validate the RSDP (ptr)
75 *
76 ******************************************************************************/
77
78static ACPI_STATUS
79AcpiTbValidateRsdp (
80    ACPI_TABLE_RSDP         *Rsdp)
81{
82    ACPI_FUNCTION_ENTRY ();
83
84
85    /*
86     * The signature and checksum must both be correct
87     *
88     * Note: Sometimes there exists more than one RSDP in memory; the valid
89     * RSDP has a valid checksum, all others have an invalid checksum.
90     */
91    if (ACPI_STRNCMP ((char *) Rsdp, ACPI_SIG_RSDP,
92            sizeof (ACPI_SIG_RSDP)-1) != 0)
93    {
94        /* Nope, BAD Signature */
95
96        return (AE_BAD_SIGNATURE);
97    }
98
99    /* Check the standard checksum */
100
101    if (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0)
102    {
103        return (AE_BAD_CHECKSUM);
104    }
105
106    /* Check extended checksum if table version >= 2 */
107
108    if ((Rsdp->Revision >= 2) &&
109        (AcpiTbChecksum ((UINT8 *) Rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0))
110    {
111        return (AE_BAD_CHECKSUM);
112    }
113
114    return (AE_OK);
115}
116
117
118/*******************************************************************************
119 *
120 * FUNCTION:    AcpiFindRootPointer
121 *
122 * PARAMETERS:  TableAddress            - Where the table pointer is returned
123 *
124 * RETURN:      Status, RSDP physical address
125 *
126 * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor
127 *              pointer structure.  If it is found, set *RSDP to point to it.
128 *
129 * NOTE1:       The RSDP must be either in the first 1K of the Extended
130 *              BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.)
131 *              Only a 32-bit physical address is necessary.
132 *
133 * NOTE2:       This function is always available, regardless of the
134 *              initialization state of the rest of ACPI.
135 *
136 ******************************************************************************/
137
138ACPI_STATUS
139AcpiFindRootPointer (
140    ACPI_SIZE               *TableAddress)
141{
142    UINT8                   *TablePtr;
143    UINT8                   *MemRover;
144    UINT32                  PhysicalAddress;
145
146
147    ACPI_FUNCTION_TRACE (AcpiFindRootPointer);
148
149
150    /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */
151
152    TablePtr = AcpiOsMapMemory (
153                (ACPI_PHYSICAL_ADDRESS) ACPI_EBDA_PTR_LOCATION,
154                ACPI_EBDA_PTR_LENGTH);
155    if (!TablePtr)
156    {
157        ACPI_ERROR ((AE_INFO,
158            "Could not map memory at 0x%8.8X for length %u",
159            ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH));
160
161        return_ACPI_STATUS (AE_NO_MEMORY);
162    }
163
164    ACPI_MOVE_16_TO_32 (&PhysicalAddress, TablePtr);
165
166    /* Convert segment part to physical address */
167
168    PhysicalAddress <<= 4;
169    AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_PTR_LENGTH);
170
171    /* EBDA present? */
172
173    if (PhysicalAddress > 0x400)
174    {
175        /*
176         * 1b) Search EBDA paragraphs (EBDA is required to be a
177         *     minimum of 1K length)
178         */
179        TablePtr = AcpiOsMapMemory (
180                    (ACPI_PHYSICAL_ADDRESS) PhysicalAddress,
181                    ACPI_EBDA_WINDOW_SIZE);
182        if (!TablePtr)
183        {
184            ACPI_ERROR ((AE_INFO,
185                "Could not map memory at 0x%8.8X for length %u",
186                PhysicalAddress, ACPI_EBDA_WINDOW_SIZE));
187
188            return_ACPI_STATUS (AE_NO_MEMORY);
189        }
190
191        MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_EBDA_WINDOW_SIZE);
192        AcpiOsUnmapMemory (TablePtr, ACPI_EBDA_WINDOW_SIZE);
193
194        if (MemRover)
195        {
196            /* Return the physical address */
197
198            PhysicalAddress += (UINT32) ACPI_PTR_DIFF (MemRover, TablePtr);
199
200            *TableAddress = PhysicalAddress;
201            return_ACPI_STATUS (AE_OK);
202        }
203    }
204
205    /*
206     * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh
207     */
208    TablePtr = AcpiOsMapMemory (
209                (ACPI_PHYSICAL_ADDRESS) ACPI_HI_RSDP_WINDOW_BASE,
210                ACPI_HI_RSDP_WINDOW_SIZE);
211
212    if (!TablePtr)
213    {
214        ACPI_ERROR ((AE_INFO,
215            "Could not map memory at 0x%8.8X for length %u",
216            ACPI_HI_RSDP_WINDOW_BASE, ACPI_HI_RSDP_WINDOW_SIZE));
217
218        return_ACPI_STATUS (AE_NO_MEMORY);
219    }
220
221    MemRover = AcpiTbScanMemoryForRsdp (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
222    AcpiOsUnmapMemory (TablePtr, ACPI_HI_RSDP_WINDOW_SIZE);
223
224    if (MemRover)
225    {
226        /* Return the physical address */
227
228        PhysicalAddress = (UINT32)
229            (ACPI_HI_RSDP_WINDOW_BASE + ACPI_PTR_DIFF (MemRover, TablePtr));
230
231        *TableAddress = PhysicalAddress;
232        return_ACPI_STATUS (AE_OK);
233    }
234
235    /* A valid RSDP was not found */
236
237    ACPI_BIOS_ERROR ((AE_INFO, "A valid RSDP was not found"));
238    return_ACPI_STATUS (AE_NOT_FOUND);
239}
240
241ACPI_EXPORT_SYMBOL (AcpiFindRootPointer)
242
243
244/*******************************************************************************
245 *
246 * FUNCTION:    AcpiTbScanMemoryForRsdp
247 *
248 * PARAMETERS:  StartAddress        - Starting pointer for search
249 *              Length              - Maximum length to search
250 *
251 * RETURN:      Pointer to the RSDP if found, otherwise NULL.
252 *
253 * DESCRIPTION: Search a block of memory for the RSDP signature
254 *
255 ******************************************************************************/
256
257static UINT8 *
258AcpiTbScanMemoryForRsdp (
259    UINT8                   *StartAddress,
260    UINT32                  Length)
261{
262    ACPI_STATUS             Status;
263    UINT8                   *MemRover;
264    UINT8                   *EndAddress;
265
266
267    ACPI_FUNCTION_TRACE (TbScanMemoryForRsdp);
268
269
270    EndAddress = StartAddress + Length;
271
272    /* Search from given start address for the requested length */
273
274    for (MemRover = StartAddress; MemRover < EndAddress;
275         MemRover += ACPI_RSDP_SCAN_STEP)
276    {
277        /* The RSDP signature and checksum must both be correct */
278
279        Status = AcpiTbValidateRsdp (ACPI_CAST_PTR (ACPI_TABLE_RSDP, MemRover));
280        if (ACPI_SUCCESS (Status))
281        {
282            /* Sig and checksum valid, we have found a real RSDP */
283
284            ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
285                "RSDP located at physical address %p\n", MemRover));
286            return_PTR (MemRover);
287        }
288
289        /* No sig match or bad checksum, keep searching */
290    }
291
292    /* Searched entire block, no RSDP was found */
293
294    ACPI_DEBUG_PRINT ((ACPI_DB_INFO,
295        "Searched entire block from %p, valid RSDP was not found\n",
296        StartAddress));
297    return_PTR (NULL);
298}
299
300