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libfdt-wrapper.c
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1 /*
2  * This file does the necessary interface mapping between the bootwrapper
3  * device tree operations and the interface provided by shared source
4  * files flatdevicetree.[ch].
5  *
6  * Copyright 2007 David Gibson, IBM Corporation.
7  *
8  * This library is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of the
11  * License, or (at your option) any later version.
12  *
13  * This library is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this library; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
21  * 02110-1301 USA
22  */
23 
24 #include <stddef.h>
25 #include <stdio.h>
26 #include <page.h>
27 #include <libfdt.h>
28 #include "ops.h"
29 
30 #define DEBUG 0
31 #define BAD_ERROR(err) (((err) < 0) \
32  && ((err) != -FDT_ERR_NOTFOUND) \
33  && ((err) != -FDT_ERR_EXISTS))
34 
35 #define check_err(err) \
36  ({ \
37  if (BAD_ERROR(err) || ((err < 0) && DEBUG)) \
38  printf("%s():%d %s\n\r", __func__, __LINE__, \
39  fdt_strerror(err)); \
40  if (BAD_ERROR(err)) \
41  exit(); \
42  (err < 0) ? -1 : 0; \
43  })
44 
45 #define offset_devp(off) \
46  ({ \
47  int _offset = (off); \
48  check_err(_offset) ? NULL : (void *)(_offset+1); \
49  })
50 
51 #define devp_offset_find(devp) (((int)(devp))-1)
52 #define devp_offset(devp) (devp ? ((int)(devp))-1 : 0)
53 
54 static void *fdt;
55 static void *buf; /* = NULL */
56 
57 #define EXPAND_GRANULARITY 1024
58 
59 static void expand_buf(int minexpand)
60 {
61  int size = fdt_totalsize(fdt);
62  int rc;
63 
64  size = _ALIGN(size + minexpand, EXPAND_GRANULARITY);
65  buf = platform_ops.realloc(buf, size);
66  if (!buf)
67  fatal("Couldn't find %d bytes to expand device tree\n\r", size);
68  rc = fdt_open_into(fdt, buf, size);
69  if (rc != 0)
70  fatal("Couldn't expand fdt into new buffer: %s\n\r",
71  fdt_strerror(rc));
72 
73  fdt = buf;
74 }
75 
76 static void *fdt_wrapper_finddevice(const char *path)
77 {
78  return offset_devp(fdt_path_offset(fdt, path));
79 }
80 
81 static int fdt_wrapper_getprop(const void *devp, const char *name,
82  void *buf, const int buflen)
83 {
84  const void *p;
85  int len;
86 
87  p = fdt_getprop(fdt, devp_offset(devp), name, &len);
88  if (!p)
89  return check_err(len);
90  memcpy(buf, p, min(len, buflen));
91  return len;
92 }
93 
94 static int fdt_wrapper_setprop(const void *devp, const char *name,
95  const void *buf, const int len)
96 {
97  int rc;
98 
99  rc = fdt_setprop(fdt, devp_offset(devp), name, buf, len);
100  if (rc == -FDT_ERR_NOSPACE) {
101  expand_buf(len + 16);
102  rc = fdt_setprop(fdt, devp_offset(devp), name, buf, len);
103  }
104 
105  return check_err(rc);
106 }
107 
108 static int fdt_wrapper_del_node(const void *devp)
109 {
110  return fdt_del_node(fdt, devp_offset(devp));
111 }
112 
113 static void *fdt_wrapper_get_parent(const void *devp)
114 {
115  return offset_devp(fdt_parent_offset(fdt, devp_offset(devp)));
116 }
117 
118 static void *fdt_wrapper_create_node(const void *devp, const char *name)
119 {
120  int offset;
121 
122  offset = fdt_add_subnode(fdt, devp_offset(devp), name);
123  if (offset == -FDT_ERR_NOSPACE) {
124  expand_buf(strlen(name) + 16);
125  offset = fdt_add_subnode(fdt, devp_offset(devp), name);
126  }
127 
128  return offset_devp(offset);
129 }
130 
131 static void *fdt_wrapper_find_node_by_prop_value(const void *prev,
132  const char *name,
133  const char *val,
134  int len)
135 {
136  int offset = fdt_node_offset_by_prop_value(fdt, devp_offset_find(prev),
137  name, val, len);
138  return offset_devp(offset);
139 }
140 
141 static void *fdt_wrapper_find_node_by_compatible(const void *prev,
142  const char *val)
143 {
144  int offset = fdt_node_offset_by_compatible(fdt, devp_offset_find(prev),
145  val);
146  return offset_devp(offset);
147 }
148 
149 static char *fdt_wrapper_get_path(const void *devp, char *buf, int len)
150 {
151  int rc;
152 
153  rc = fdt_get_path(fdt, devp_offset(devp), buf, len);
154  if (check_err(rc))
155  return NULL;
156  return buf;
157 }
158 
159 static unsigned long fdt_wrapper_finalize(void)
160 {
161  int rc;
162 
163  rc = fdt_pack(fdt);
164  if (rc != 0)
165  fatal("Couldn't pack flat tree: %s\n\r",
166  fdt_strerror(rc));
167  return (unsigned long)fdt;
168 }
169 
170 void fdt_init(void *blob)
171 {
172  int err;
173  int bufsize;
174 
175  dt_ops.finddevice = fdt_wrapper_finddevice;
176  dt_ops.getprop = fdt_wrapper_getprop;
177  dt_ops.setprop = fdt_wrapper_setprop;
178  dt_ops.get_parent = fdt_wrapper_get_parent;
179  dt_ops.create_node = fdt_wrapper_create_node;
180  dt_ops.find_node_by_prop_value = fdt_wrapper_find_node_by_prop_value;
181  dt_ops.find_node_by_compatible = fdt_wrapper_find_node_by_compatible;
182  dt_ops.del_node = fdt_wrapper_del_node;
183  dt_ops.get_path = fdt_wrapper_get_path;
184  dt_ops.finalize = fdt_wrapper_finalize;
185 
186  /* Make sure the dt blob is the right version and so forth */
187  fdt = blob;
188  bufsize = fdt_totalsize(fdt) + EXPAND_GRANULARITY;
189  buf = malloc(bufsize);
190  if(!buf)
191  fatal("malloc failed. can't relocate the device tree\n\r");
192 
193  err = fdt_open_into(fdt, buf, bufsize);
194 
195  if (err != 0)
196  fatal("fdt_init(): %s\n\r", fdt_strerror(err));
197 
198  fdt = buf;
199 }