ib_packer.c revision 331769 
1/*
2 * Copyright (c) 2004 Topspin Corporation.  All rights reserved.
3 * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
4 *
5 * This software is available to you under a choice of one of two
6 * licenses.  You may choose to be licensed under the terms of the GNU
7 * General Public License (GPL) Version 2, available from the file
8 * COPYING in the main directory of this source tree, or the
9 * OpenIB.org BSD license below:
10 *
11 *     Redistribution and use in source and binary forms, with or
12 *     without modification, are permitted provided that the following
13 *     conditions are met:
14 *
15 *      - Redistributions of source code must retain the above
16 *        copyright notice, this list of conditions and the following
17 *        disclaimer.
18 *
19 *      - Redistributions in binary form must reproduce the above
20 *        copyright notice, this list of conditions and the following
21 *        disclaimer in the documentation and/or other materials
22 *        provided with the distribution.
23 *
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31 * SOFTWARE.
32 */
33
34#include <linux/string.h>
35
36#include <rdma/ib_pack.h>
37
38static u64 value_read(int offset, int size, void *structure)
39{
40	switch (size) {
41	case 1: return                *(u8  *) ((char *)structure + offset);
42	case 2: return be16_to_cpup((__be16 *) ((char *)structure + offset));
43	case 4: return be32_to_cpup((__be32 *) ((char *)structure + offset));
44	case 8: return be64_to_cpup((__be64 *) ((char *)structure + offset));
45	default:
46		pr_warn("Field size %d bits not handled\n", size * 8);
47		return 0;
48	}
49}
50
51/**
52 * ib_pack - Pack a structure into a buffer
53 * @desc:Array of structure field descriptions
54 * @desc_len:Number of entries in @desc
55 * @structure:Structure to pack from
56 * @buf:Buffer to pack into
57 *
58 * ib_pack() packs a list of structure fields into a buffer,
59 * controlled by the array of fields in @desc.
60 */
61void ib_pack(const struct ib_field        *desc,
62	     int                           desc_len,
63	     void                         *structure,
64	     void                         *buf)
65{
66	int i;
67
68	for (i = 0; i < desc_len; ++i) {
69		if (desc[i].size_bits <= 32) {
70			int shift;
71			u32 val;
72			__be32 mask;
73			__be32 *addr;
74
75			shift = 32 - desc[i].offset_bits - desc[i].size_bits;
76			if (desc[i].struct_size_bytes)
77				val = value_read(desc[i].struct_offset_bytes,
78						 desc[i].struct_size_bytes,
79						 structure) << shift;
80			else
81				val = 0;
82
83			mask = cpu_to_be32(((1ull << desc[i].size_bits) - 1) << shift);
84			addr = (__be32 *) buf + desc[i].offset_words;
85			*addr = (*addr & ~mask) | (cpu_to_be32(val) & mask);
86		} else if (desc[i].size_bits <= 64) {
87			int shift;
88			u64 val;
89			__be64 mask;
90			__be64 *addr;
91
92			shift = 64 - desc[i].offset_bits - desc[i].size_bits;
93			if (desc[i].struct_size_bytes)
94				val = value_read(desc[i].struct_offset_bytes,
95						 desc[i].struct_size_bytes,
96						 structure) << shift;
97			else
98				val = 0;
99
100			mask = cpu_to_be64((~0ull >> (64 - desc[i].size_bits)) << shift);
101			addr = (__be64 *) ((__be32 *) buf + desc[i].offset_words);
102			*addr = (*addr & ~mask) | (cpu_to_be64(val) & mask);
103		} else {
104			if (desc[i].offset_bits % 8 ||
105			    desc[i].size_bits   % 8) {
106				pr_warn("Structure field %s of size %d bits is not byte-aligned\n",
107					desc[i].field_name, desc[i].size_bits);
108			}
109
110			if (desc[i].struct_size_bytes)
111				memcpy((char *)buf + desc[i].offset_words * 4 +
112				       desc[i].offset_bits / 8,
113				       (char *)structure + desc[i].struct_offset_bytes,
114				       desc[i].size_bits / 8);
115			else
116				memset((char *)buf + desc[i].offset_words * 4 +
117				       desc[i].offset_bits / 8,
118				       0,
119				       desc[i].size_bits / 8);
120		}
121	}
122}
123EXPORT_SYMBOL(ib_pack);
124
125static void value_write(int offset, int size, u64 val, void *structure)
126{
127	switch (size * 8) {
128	case 8:  *(    u8 *) ((char *)structure + offset) = val; break;
129	case 16: *(__be16 *) ((char *)structure + offset) = cpu_to_be16(val); break;
130	case 32: *(__be32 *) ((char *)structure + offset) = cpu_to_be32(val); break;
131	case 64: *(__be64 *) ((char *)structure + offset) = cpu_to_be64(val); break;
132	default:
133		pr_warn("Field size %d bits not handled\n", size * 8);
134	}
135}
136
137/**
138 * ib_unpack - Unpack a buffer into a structure
139 * @desc:Array of structure field descriptions
140 * @desc_len:Number of entries in @desc
141 * @buf:Buffer to unpack from
142 * @structure:Structure to unpack into
143 *
144 * ib_pack() unpacks a list of structure fields from a buffer,
145 * controlled by the array of fields in @desc.
146 */
147void ib_unpack(const struct ib_field        *desc,
148	       int                           desc_len,
149	       void                         *buf,
150	       void                         *structure)
151{
152	int i;
153
154	for (i = 0; i < desc_len; ++i) {
155		if (!desc[i].struct_size_bytes)
156			continue;
157
158		if (desc[i].size_bits <= 32) {
159			int shift;
160			u32  val;
161			u32  mask;
162			__be32 *addr;
163
164			shift = 32 - desc[i].offset_bits - desc[i].size_bits;
165			mask = ((1ull << desc[i].size_bits) - 1) << shift;
166			addr = (__be32 *) buf + desc[i].offset_words;
167			val = (be32_to_cpup(addr) & mask) >> shift;
168			value_write(desc[i].struct_offset_bytes,
169				    desc[i].struct_size_bytes,
170				    val,
171				    structure);
172		} else if (desc[i].size_bits <= 64) {
173			int shift;
174			u64  val;
175			u64  mask;
176			__be64 *addr;
177
178			shift = 64 - desc[i].offset_bits - desc[i].size_bits;
179			mask = (~0ull >> (64 - desc[i].size_bits)) << shift;
180			addr = (__be64 *) buf + desc[i].offset_words;
181			val = (be64_to_cpup(addr) & mask) >> shift;
182			value_write(desc[i].struct_offset_bytes,
183				    desc[i].struct_size_bytes,
184				    val,
185				    structure);
186		} else {
187			if (desc[i].offset_bits % 8 ||
188			    desc[i].size_bits   % 8) {
189				pr_warn("Structure field %s of size %d bits is not byte-aligned\n",
190					desc[i].field_name, desc[i].size_bits);
191			}
192
193			memcpy((char *)structure + desc[i].struct_offset_bytes,
194			       (char *)buf + desc[i].offset_words * 4 +
195			       desc[i].offset_bits / 8,
196			       desc[i].size_bits / 8);
197		}
198	}
199}
200EXPORT_SYMBOL(ib_unpack);
201