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1da177e4 LT |
1 | /****************************************************************************** |
2 | * | |
3 | * Module Name: tbxfroot - Find the root ACPI table (RSDT) | |
4 | * | |
5 | *****************************************************************************/ | |
6 | ||
7 | /* | |
c8100dc4 | 8 | * Copyright (C) 2000 - 2016, 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> |
e2f7a777 LB |
45 | #include "accommon.h" |
46 | #include "actables.h" | |
1da177e4 | 47 | |
1da177e4 | 48 | #define _COMPONENT ACPI_TABLES |
4be44fcd | 49 | ACPI_MODULE_NAME("tbxfroot") |
1da177e4 | 50 | |
f1b69752 LZ |
51 | /******************************************************************************* |
52 | * | |
53 | * FUNCTION: acpi_tb_get_rsdp_length | |
54 | * | |
55 | * PARAMETERS: rsdp - Pointer to RSDP | |
56 | * | |
57 | * RETURN: Table length | |
58 | * | |
59 | * DESCRIPTION: Get the length of the RSDP | |
60 | * | |
61 | ******************************************************************************/ | |
62 | u32 acpi_tb_get_rsdp_length(struct acpi_table_rsdp *rsdp) | |
63 | { | |
64 | ||
65 | if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature)) { | |
66 | ||
67 | /* BAD Signature */ | |
68 | ||
69 | return (0); | |
70 | } | |
71 | ||
72 | /* "Length" field is available if table version >= 2 */ | |
73 | ||
74 | if (rsdp->revision >= 2) { | |
75 | return (rsdp->length); | |
76 | } else { | |
77 | return (ACPI_RSDP_CHECKSUM_LENGTH); | |
78 | } | |
79 | } | |
80 | ||
f9f4601f RM |
81 | /******************************************************************************* |
82 | * | |
83 | * FUNCTION: acpi_tb_validate_rsdp | |
84 | * | |
ba494bee | 85 | * PARAMETERS: rsdp - Pointer to unvalidated RSDP |
f9f4601f RM |
86 | * |
87 | * RETURN: Status | |
88 | * | |
89 | * DESCRIPTION: Validate the RSDP (ptr) | |
90 | * | |
91 | ******************************************************************************/ | |
f1b69752 | 92 | |
f5c1e1c5 | 93 | acpi_status acpi_tb_validate_rsdp(struct acpi_table_rsdp *rsdp) |
f9f4601f | 94 | { |
f9f4601f RM |
95 | |
96 | /* | |
f3d2e786 BM |
97 | * The signature and checksum must both be correct |
98 | * | |
99 | * Note: Sometimes there exists more than one RSDP in memory; the valid | |
100 | * RSDP has a valid checksum, all others have an invalid checksum. | |
f9f4601f | 101 | */ |
cacba865 | 102 | if (!ACPI_VALIDATE_RSDP_SIG(rsdp->signature)) { |
52fc0b02 | 103 | |
f9f4601f RM |
104 | /* Nope, BAD Signature */ |
105 | ||
106 | return (AE_BAD_SIGNATURE); | |
107 | } | |
108 | ||
109 | /* Check the standard checksum */ | |
110 | ||
f3d2e786 | 111 | if (acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_CHECKSUM_LENGTH) != 0) { |
f9f4601f RM |
112 | return (AE_BAD_CHECKSUM); |
113 | } | |
114 | ||
115 | /* Check extended checksum if table version >= 2 */ | |
116 | ||
117 | if ((rsdp->revision >= 2) && | |
f3d2e786 | 118 | (acpi_tb_checksum((u8 *) rsdp, ACPI_RSDP_XCHECKSUM_LENGTH) != 0)) { |
f9f4601f RM |
119 | return (AE_BAD_CHECKSUM); |
120 | } | |
121 | ||
122 | return (AE_OK); | |
123 | } | |
124 | ||
1da177e4 LT |
125 | /******************************************************************************* |
126 | * | |
239665a3 | 127 | * FUNCTION: acpi_find_root_pointer |
1da177e4 | 128 | * |
f3d2e786 | 129 | * PARAMETERS: table_address - Where the table pointer is returned |
1da177e4 | 130 | * |
f3d2e786 | 131 | * RETURN: Status, RSDP physical address |
1da177e4 | 132 | * |
ba494bee | 133 | * DESCRIPTION: Search lower 1Mbyte of memory for the root system descriptor |
73a3090a | 134 | * pointer structure. If it is found, set *RSDP to point to it. |
1da177e4 | 135 | * |
ba494bee | 136 | * NOTE1: The RSDP must be either in the first 1K of the Extended |
f3d2e786 BM |
137 | * BIOS Data Area or between E0000 and FFFFF (From ACPI Spec.) |
138 | * Only a 32-bit physical address is necessary. | |
1da177e4 | 139 | * |
f3d2e786 BM |
140 | * NOTE2: This function is always available, regardless of the |
141 | * initialization state of the rest of ACPI. | |
1da177e4 LT |
142 | * |
143 | ******************************************************************************/ | |
144 | ||
f5c1e1c5 | 145 | acpi_status __init acpi_find_root_pointer(acpi_physical_address *table_address) |
1da177e4 | 146 | { |
f3d2e786 BM |
147 | u8 *table_ptr; |
148 | u8 *mem_rover; | |
149 | u32 physical_address; | |
1da177e4 | 150 | |
f3d2e786 | 151 | ACPI_FUNCTION_TRACE(acpi_find_root_pointer); |
1da177e4 | 152 | |
f3d2e786 | 153 | /* 1a) Get the location of the Extended BIOS Data Area (EBDA) */ |
1da177e4 | 154 | |
f3d2e786 BM |
155 | table_ptr = acpi_os_map_memory((acpi_physical_address) |
156 | ACPI_EBDA_PTR_LOCATION, | |
157 | ACPI_EBDA_PTR_LENGTH); | |
158 | if (!table_ptr) { | |
159 | ACPI_ERROR((AE_INFO, | |
f6a22b0b | 160 | "Could not map memory at 0x%8.8X for length %u", |
f3d2e786 | 161 | ACPI_EBDA_PTR_LOCATION, ACPI_EBDA_PTR_LENGTH)); |
1da177e4 | 162 | |
4be44fcd | 163 | return_ACPI_STATUS(AE_NO_MEMORY); |
1da177e4 LT |
164 | } |
165 | ||
f3d2e786 | 166 | ACPI_MOVE_16_TO_32(&physical_address, table_ptr); |
1da177e4 | 167 | |
f3d2e786 | 168 | /* Convert segment part to physical address */ |
1da177e4 | 169 | |
f3d2e786 BM |
170 | physical_address <<= 4; |
171 | acpi_os_unmap_memory(table_ptr, ACPI_EBDA_PTR_LENGTH); | |
1da177e4 | 172 | |
f3d2e786 | 173 | /* EBDA present? */ |
1da177e4 | 174 | |
f3d2e786 | 175 | if (physical_address > 0x400) { |
73459f73 | 176 | /* |
f3d2e786 | 177 | * 1b) Search EBDA paragraphs (EBDA is required to be a |
ba494bee | 178 | * minimum of 1K length) |
73459f73 | 179 | */ |
67a119f9 | 180 | table_ptr = acpi_os_map_memory((acpi_physical_address) |
f3d2e786 BM |
181 | physical_address, |
182 | ACPI_EBDA_WINDOW_SIZE); | |
183 | if (!table_ptr) { | |
184 | ACPI_ERROR((AE_INFO, | |
f6a22b0b | 185 | "Could not map memory at 0x%8.8X for length %u", |
f3d2e786 | 186 | physical_address, ACPI_EBDA_WINDOW_SIZE)); |
1da177e4 | 187 | |
f3d2e786 | 188 | return_ACPI_STATUS(AE_NO_MEMORY); |
1da177e4 LT |
189 | } |
190 | ||
f3d2e786 BM |
191 | mem_rover = |
192 | acpi_tb_scan_memory_for_rsdp(table_ptr, | |
193 | ACPI_EBDA_WINDOW_SIZE); | |
194 | acpi_os_unmap_memory(table_ptr, ACPI_EBDA_WINDOW_SIZE); | |
1da177e4 | 195 | |
f3d2e786 | 196 | if (mem_rover) { |
52fc0b02 | 197 | |
f3d2e786 | 198 | /* Return the physical address */ |
1da177e4 | 199 | |
f3d2e786 BM |
200 | physical_address += |
201 | (u32) ACPI_PTR_DIFF(mem_rover, table_ptr); | |
1da177e4 | 202 | |
f254e3c5 | 203 | *table_address = |
f5c1e1c5 | 204 | (acpi_physical_address)physical_address; |
f3d2e786 | 205 | return_ACPI_STATUS(AE_OK); |
1da177e4 LT |
206 | } |
207 | } | |
208 | ||
f3d2e786 BM |
209 | /* |
210 | * 2) Search upper memory: 16-byte boundaries in E0000h-FFFFFh | |
211 | */ | |
212 | table_ptr = acpi_os_map_memory((acpi_physical_address) | |
213 | ACPI_HI_RSDP_WINDOW_BASE, | |
214 | ACPI_HI_RSDP_WINDOW_SIZE); | |
1da177e4 | 215 | |
f3d2e786 BM |
216 | if (!table_ptr) { |
217 | ACPI_ERROR((AE_INFO, | |
f6a22b0b | 218 | "Could not map memory at 0x%8.8X for length %u", |
f3d2e786 BM |
219 | ACPI_HI_RSDP_WINDOW_BASE, |
220 | ACPI_HI_RSDP_WINDOW_SIZE)); | |
1da177e4 | 221 | |
f3d2e786 | 222 | return_ACPI_STATUS(AE_NO_MEMORY); |
88ac00f5 | 223 | } |
1da177e4 | 224 | |
f3d2e786 BM |
225 | mem_rover = |
226 | acpi_tb_scan_memory_for_rsdp(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE); | |
227 | acpi_os_unmap_memory(table_ptr, ACPI_HI_RSDP_WINDOW_SIZE); | |
1da177e4 | 228 | |
f3d2e786 | 229 | if (mem_rover) { |
1da177e4 | 230 | |
f3d2e786 | 231 | /* Return the physical address */ |
1da177e4 | 232 | |
f3d2e786 BM |
233 | physical_address = (u32) |
234 | (ACPI_HI_RSDP_WINDOW_BASE + | |
235 | ACPI_PTR_DIFF(mem_rover, table_ptr)); | |
1da177e4 | 236 | |
f5c1e1c5 | 237 | *table_address = (acpi_physical_address)physical_address; |
f3d2e786 | 238 | return_ACPI_STATUS(AE_OK); |
1da177e4 LT |
239 | } |
240 | ||
f3d2e786 BM |
241 | /* A valid RSDP was not found */ |
242 | ||
3b3ea775 | 243 | ACPI_BIOS_ERROR((AE_INFO, "A valid RSDP was not found")); |
f3d2e786 | 244 | return_ACPI_STATUS(AE_NOT_FOUND); |
1da177e4 LT |
245 | } |
246 | ||
1da177e4 LT |
247 | /******************************************************************************* |
248 | * | |
249 | * FUNCTION: acpi_tb_scan_memory_for_rsdp | |
250 | * | |
251 | * PARAMETERS: start_address - Starting pointer for search | |
ba494bee | 252 | * length - Maximum length to search |
1da177e4 LT |
253 | * |
254 | * RETURN: Pointer to the RSDP if found, otherwise NULL. | |
255 | * | |
256 | * DESCRIPTION: Search a block of memory for the RSDP signature | |
257 | * | |
258 | ******************************************************************************/ | |
57987ca2 | 259 | u8 *acpi_tb_scan_memory_for_rsdp(u8 *start_address, u32 length) |
1da177e4 | 260 | { |
4be44fcd LB |
261 | acpi_status status; |
262 | u8 *mem_rover; | |
263 | u8 *end_address; | |
1da177e4 | 264 | |
b229cf92 | 265 | ACPI_FUNCTION_TRACE(tb_scan_memory_for_rsdp); |
1da177e4 LT |
266 | |
267 | end_address = start_address + length; | |
268 | ||
269 | /* Search from given start address for the requested length */ | |
270 | ||
271 | for (mem_rover = start_address; mem_rover < end_address; | |
4be44fcd | 272 | mem_rover += ACPI_RSDP_SCAN_STEP) { |
52fc0b02 | 273 | |
f9f4601f | 274 | /* The RSDP signature and checksum must both be correct */ |
1da177e4 | 275 | |
4be44fcd LB |
276 | status = |
277 | acpi_tb_validate_rsdp(ACPI_CAST_PTR | |
f3d2e786 | 278 | (struct acpi_table_rsdp, mem_rover)); |
4be44fcd | 279 | if (ACPI_SUCCESS(status)) { |
52fc0b02 | 280 | |
f9f4601f | 281 | /* Sig and checksum valid, we have found a real RSDP */ |
1da177e4 | 282 | |
4be44fcd LB |
283 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, |
284 | "RSDP located at physical address %p\n", | |
285 | mem_rover)); | |
286 | return_PTR(mem_rover); | |
1da177e4 LT |
287 | } |
288 | ||
f9f4601f | 289 | /* No sig match or bad checksum, keep searching */ |
1da177e4 LT |
290 | } |
291 | ||
292 | /* Searched entire block, no RSDP was found */ | |
293 | ||
4be44fcd LB |
294 | ACPI_DEBUG_PRINT((ACPI_DB_INFO, |
295 | "Searched entire block from %p, valid RSDP was not found\n", | |
296 | start_address)); | |
297 | return_PTR(NULL); | |
1da177e4 | 298 | } |