Merge master.kernel.org:/home/rmk/linux-2.6-mmc
[linux-2.6] / drivers / acpi / tables / tbutils.c
1 /******************************************************************************
2  *
3  * Module Name: tbutils - Table manipulation utilities
4  *
5  *****************************************************************************/
6
7 /*
8  * Copyright (C) 2000 - 2005, R. Byron Moore
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 #include <acpi/acpi.h>
45 #include <acpi/actables.h>
46
47 #define _COMPONENT          ACPI_TABLES
48 ACPI_MODULE_NAME("tbutils")
49
50 /* Local prototypes */
51 #ifdef ACPI_OBSOLETE_FUNCTIONS
52 acpi_status
53 acpi_tb_handle_to_object(u16 table_id, struct acpi_table_desc **table_desc);
54 #endif
55
56 /*******************************************************************************
57  *
58  * FUNCTION:    acpi_tb_is_table_installed
59  *
60  * PARAMETERS:  new_table_desc      - Descriptor for new table being installed
61  *
62  * RETURN:      Status - AE_ALREADY_EXISTS if the table is already installed
63  *
64  * DESCRIPTION: Determine if an ACPI table is already installed
65  *
66  * MUTEX:       Table data structures should be locked
67  *
68  ******************************************************************************/
69
70 acpi_status acpi_tb_is_table_installed(struct acpi_table_desc *new_table_desc)
71 {
72         struct acpi_table_desc *table_desc;
73
74         ACPI_FUNCTION_TRACE("tb_is_table_installed");
75
76         /* Get the list descriptor and first table descriptor */
77
78         table_desc = acpi_gbl_table_lists[new_table_desc->type].next;
79
80         /* Examine all installed tables of this type */
81
82         while (table_desc) {
83                 /*
84                  * If the table lengths match, perform a full bytewise compare. This
85                  * means that we will allow tables with duplicate oem_table_id(s), as
86                  * long as the tables are different in some way.
87                  *
88                  * Checking if the table has been loaded into the namespace means that
89                  * we don't check for duplicate tables during the initial installation
90                  * of tables within the RSDT/XSDT.
91                  */
92                 if ((table_desc->loaded_into_namespace) &&
93                     (table_desc->pointer->length ==
94                      new_table_desc->pointer->length)
95                     &&
96                     (!ACPI_MEMCMP
97                      ((const char *)table_desc->pointer,
98                       (const char *)new_table_desc->pointer,
99                       (acpi_size) new_table_desc->pointer->length))) {
100                         /* Match: this table is already installed */
101
102                         ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
103                                           "Table [%4.4s] already installed: Rev %X oem_table_id [%8.8s]\n",
104                                           new_table_desc->pointer->signature,
105                                           new_table_desc->pointer->revision,
106                                           new_table_desc->pointer->
107                                           oem_table_id));
108
109                         new_table_desc->owner_id = table_desc->owner_id;
110                         new_table_desc->installed_desc = table_desc;
111
112                         return_ACPI_STATUS(AE_ALREADY_EXISTS);
113                 }
114
115                 /* Get next table on the list */
116
117                 table_desc = table_desc->next;
118         }
119
120         return_ACPI_STATUS(AE_OK);
121 }
122
123 /*******************************************************************************
124  *
125  * FUNCTION:    acpi_tb_validate_table_header
126  *
127  * PARAMETERS:  table_header        - Logical pointer to the table
128  *
129  * RETURN:      Status
130  *
131  * DESCRIPTION: Check an ACPI table header for validity
132  *
133  * NOTE:  Table pointers are validated as follows:
134  *          1) Table pointer must point to valid physical memory
135  *          2) Signature must be 4 ASCII chars, even if we don't recognize the
136  *             name
137  *          3) Table must be readable for length specified in the header
138  *          4) Table checksum must be valid (with the exception of the FACS
139  *              which has no checksum because it contains variable fields)
140  *
141  ******************************************************************************/
142
143 acpi_status
144 acpi_tb_validate_table_header(struct acpi_table_header *table_header)
145 {
146         acpi_name signature;
147
148         ACPI_FUNCTION_NAME("tb_validate_table_header");
149
150         /* Verify that this is a valid address */
151
152         if (!acpi_os_readable(table_header, sizeof(struct acpi_table_header))) {
153                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
154                                   "Cannot read table header at %p\n",
155                                   table_header));
156
157                 return (AE_BAD_ADDRESS);
158         }
159
160         /* Ensure that the signature is 4 ASCII characters */
161
162         ACPI_MOVE_32_TO_32(&signature, table_header->signature);
163         if (!acpi_ut_valid_acpi_name(signature)) {
164                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
165                                   "Table signature at %p [%p] has invalid characters\n",
166                                   table_header, &signature));
167
168                 ACPI_REPORT_WARNING(("Invalid table signature found: [%4.4s]\n",
169                                      (char *)&signature));
170
171                 ACPI_DUMP_BUFFER(table_header,
172                                  sizeof(struct acpi_table_header));
173                 return (AE_BAD_SIGNATURE);
174         }
175
176         /* Validate the table length */
177
178         if (table_header->length < sizeof(struct acpi_table_header)) {
179                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
180                                   "Invalid length in table header %p name %4.4s\n",
181                                   table_header, (char *)&signature));
182
183                 ACPI_REPORT_WARNING(("Invalid table header length (0x%X) found\n", (u32) table_header->length));
184
185                 ACPI_DUMP_BUFFER(table_header,
186                                  sizeof(struct acpi_table_header));
187                 return (AE_BAD_HEADER);
188         }
189
190         return (AE_OK);
191 }
192
193 /*******************************************************************************
194  *
195  * FUNCTION:    acpi_tb_verify_table_checksum
196  *
197  * PARAMETERS:  *table_header           - ACPI table to verify
198  *
199  * RETURN:      8 bit checksum of table
200  *
201  * DESCRIPTION: Does an 8 bit checksum of table and returns status.  A correct
202  *              table should have a checksum of 0.
203  *
204  ******************************************************************************/
205
206 acpi_status
207 acpi_tb_verify_table_checksum(struct acpi_table_header * table_header)
208 {
209         u8 checksum;
210         acpi_status status = AE_OK;
211
212         ACPI_FUNCTION_TRACE("tb_verify_table_checksum");
213
214         /* Compute the checksum on the table */
215
216         checksum =
217             acpi_tb_generate_checksum(table_header, table_header->length);
218
219         /* Return the appropriate exception */
220
221         if (checksum) {
222                 ACPI_REPORT_WARNING(("Invalid checksum in table [%4.4s] (%02X, sum %02X is not zero)\n", table_header->signature, (u32) table_header->checksum, (u32) checksum));
223
224                 status = AE_BAD_CHECKSUM;
225         }
226         return_ACPI_STATUS(status);
227 }
228
229 /*******************************************************************************
230  *
231  * FUNCTION:    acpi_tb_generate_checksum
232  *
233  * PARAMETERS:  Buffer              - Buffer to checksum
234  *              Length              - Size of the buffer
235  *
236  * RETURN:      8 bit checksum of buffer
237  *
238  * DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
239  *
240  ******************************************************************************/
241
242 u8 acpi_tb_generate_checksum(void *buffer, u32 length)
243 {
244         const u8 *limit;
245         const u8 *rover;
246         u8 sum = 0;
247
248         if (buffer && length) {
249                 /*  Buffer and Length are valid   */
250
251                 limit = (u8 *) buffer + length;
252
253                 for (rover = buffer; rover < limit; rover++) {
254                         sum = (u8) (sum + *rover);
255                 }
256         }
257         return (sum);
258 }
259
260 #ifdef ACPI_OBSOLETE_FUNCTIONS
261 /*******************************************************************************
262  *
263  * FUNCTION:    acpi_tb_handle_to_object
264  *
265  * PARAMETERS:  table_id            - Id for which the function is searching
266  *              table_desc          - Pointer to return the matching table
267  *                                      descriptor.
268  *
269  * RETURN:      Search the tables to find one with a matching table_id and
270  *              return a pointer to that table descriptor.
271  *
272  ******************************************************************************/
273
274 acpi_status
275 acpi_tb_handle_to_object(u16 table_id,
276                          struct acpi_table_desc ** return_table_desc)
277 {
278         u32 i;
279         struct acpi_table_desc *table_desc;
280
281         ACPI_FUNCTION_NAME("tb_handle_to_object");
282
283         for (i = 0; i < ACPI_TABLE_MAX; i++) {
284                 table_desc = acpi_gbl_table_lists[i].next;
285                 while (table_desc) {
286                         if (table_desc->table_id == table_id) {
287                                 *return_table_desc = table_desc;
288                                 return (AE_OK);
289                         }
290
291                         table_desc = table_desc->next;
292                 }
293         }
294
295         ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "table_id=%X does not exist\n",
296                           table_id));
297         return (AE_BAD_PARAMETER);
298 }
299 #endif