Merge git://git.infradead.org/mtd-2.6
[linux-2.6] / drivers / acpi / executer / exstorob.c
1
2 /******************************************************************************
3  *
4  * Module Name: exstorob - AML Interpreter object store support, store to object
5  *
6  *****************************************************************************/
7
8 /*
9  * Copyright (C) 2000 - 2007, R. Byron Moore
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions, and the following disclaimer,
17  *    without modification.
18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19  *    substantially similar to the "NO WARRANTY" disclaimer below
20  *    ("Disclaimer") and any redistribution must be conditioned upon
21  *    including a substantially similar Disclaimer requirement for further
22  *    binary redistribution.
23  * 3. Neither the names of the above-listed copyright holders nor the names
24  *    of any contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * Alternatively, this software may be distributed under the terms of the
28  * GNU General Public License ("GPL") version 2 as published by the Free
29  * Software Foundation.
30  *
31  * NO WARRANTY
32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42  * POSSIBILITY OF SUCH DAMAGES.
43  */
44
45 #include <acpi/acpi.h>
46 #include <acpi/acinterp.h>
47
48 #define _COMPONENT          ACPI_EXECUTER
49 ACPI_MODULE_NAME("exstorob")
50
51 /*******************************************************************************
52  *
53  * FUNCTION:    acpi_ex_store_buffer_to_buffer
54  *
55  * PARAMETERS:  source_desc         - Source object to copy
56  *              target_desc         - Destination object of the copy
57  *
58  * RETURN:      Status
59  *
60  * DESCRIPTION: Copy a buffer object to another buffer object.
61  *
62  ******************************************************************************/
63 acpi_status
64 acpi_ex_store_buffer_to_buffer(union acpi_operand_object *source_desc,
65                                union acpi_operand_object *target_desc)
66 {
67         u32 length;
68         u8 *buffer;
69
70         ACPI_FUNCTION_TRACE_PTR(ex_store_buffer_to_buffer, source_desc);
71
72         /* We know that source_desc is a buffer by now */
73
74         buffer = ACPI_CAST_PTR(u8, source_desc->buffer.pointer);
75         length = source_desc->buffer.length;
76
77         /*
78          * If target is a buffer of length zero or is a static buffer,
79          * allocate a new buffer of the proper length
80          */
81         if ((target_desc->buffer.length == 0) ||
82             (target_desc->common.flags & AOPOBJ_STATIC_POINTER)) {
83                 target_desc->buffer.pointer = ACPI_ALLOCATE(length);
84                 if (!target_desc->buffer.pointer) {
85                         return_ACPI_STATUS(AE_NO_MEMORY);
86                 }
87
88                 target_desc->buffer.length = length;
89         }
90
91         /* Copy source buffer to target buffer */
92
93         if (length <= target_desc->buffer.length) {
94
95                 /* Clear existing buffer and copy in the new one */
96
97                 ACPI_MEMSET(target_desc->buffer.pointer, 0,
98                             target_desc->buffer.length);
99                 ACPI_MEMCPY(target_desc->buffer.pointer, buffer, length);
100
101 #ifdef ACPI_OBSOLETE_BEHAVIOR
102                 /*
103                  * NOTE: ACPI versions up to 3.0 specified that the buffer must be
104                  * truncated if the string is smaller than the buffer.  However, "other"
105                  * implementations of ACPI never did this and thus became the defacto
106                  * standard. ACPI 3.0_a changes this behavior such that the buffer
107                  * is no longer truncated.
108                  */
109
110                 /*
111                  * OBSOLETE BEHAVIOR:
112                  * If the original source was a string, we must truncate the buffer,
113                  * according to the ACPI spec.  Integer-to-Buffer and Buffer-to-Buffer
114                  * copy must not truncate the original buffer.
115                  */
116                 if (original_src_type == ACPI_TYPE_STRING) {
117
118                         /* Set the new length of the target */
119
120                         target_desc->buffer.length = length;
121                 }
122 #endif
123         } else {
124                 /* Truncate the source, copy only what will fit */
125
126                 ACPI_MEMCPY(target_desc->buffer.pointer, buffer,
127                             target_desc->buffer.length);
128
129                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
130                                   "Truncating source buffer from %X to %X\n",
131                                   length, target_desc->buffer.length));
132         }
133
134         /* Copy flags */
135
136         target_desc->buffer.flags = source_desc->buffer.flags;
137         target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
138         return_ACPI_STATUS(AE_OK);
139 }
140
141 /*******************************************************************************
142  *
143  * FUNCTION:    acpi_ex_store_string_to_string
144  *
145  * PARAMETERS:  source_desc         - Source object to copy
146  *              target_desc         - Destination object of the copy
147  *
148  * RETURN:      Status
149  *
150  * DESCRIPTION: Copy a String object to another String object
151  *
152  ******************************************************************************/
153
154 acpi_status
155 acpi_ex_store_string_to_string(union acpi_operand_object *source_desc,
156                                union acpi_operand_object *target_desc)
157 {
158         u32 length;
159         u8 *buffer;
160
161         ACPI_FUNCTION_TRACE_PTR(ex_store_string_to_string, source_desc);
162
163         /* We know that source_desc is a string by now */
164
165         buffer = ACPI_CAST_PTR(u8, source_desc->string.pointer);
166         length = source_desc->string.length;
167
168         /*
169          * Replace existing string value if it will fit and the string
170          * pointer is not a static pointer (part of an ACPI table)
171          */
172         if ((length < target_desc->string.length) &&
173             (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
174                 /*
175                  * String will fit in existing non-static buffer.
176                  * Clear old string and copy in the new one
177                  */
178                 ACPI_MEMSET(target_desc->string.pointer, 0,
179                             (acpi_size) target_desc->string.length + 1);
180                 ACPI_MEMCPY(target_desc->string.pointer, buffer, length);
181         } else {
182                 /*
183                  * Free the current buffer, then allocate a new buffer
184                  * large enough to hold the value
185                  */
186                 if (target_desc->string.pointer &&
187                     (!(target_desc->common.flags & AOPOBJ_STATIC_POINTER))) {
188
189                         /* Only free if not a pointer into the DSDT */
190
191                         ACPI_FREE(target_desc->string.pointer);
192                 }
193
194                 target_desc->string.pointer = ACPI_ALLOCATE_ZEROED((acpi_size)
195                                                                    length + 1);
196                 if (!target_desc->string.pointer) {
197                         return_ACPI_STATUS(AE_NO_MEMORY);
198                 }
199
200                 target_desc->common.flags &= ~AOPOBJ_STATIC_POINTER;
201                 ACPI_MEMCPY(target_desc->string.pointer, buffer, length);
202         }
203
204         /* Set the new target length */
205
206         target_desc->string.length = length;
207         return_ACPI_STATUS(AE_OK);
208 }