Driver for the Atmel on-chip SSC on AT32AP and AT91
[linux-2.6] / drivers / mtd / redboot.c
1 /*
2  * $Id: redboot.c,v 1.21 2006/03/30 18:34:37 bjd Exp $
3  *
4  * Parse RedBoot-style Flash Image System (FIS) tables and
5  * produce a Linux partition array to match.
6  */
7
8 #include <linux/kernel.h>
9 #include <linux/slab.h>
10 #include <linux/init.h>
11 #include <linux/vmalloc.h>
12
13 #include <linux/mtd/mtd.h>
14 #include <linux/mtd/partitions.h>
15
16 struct fis_image_desc {
17     unsigned char name[16];      // Null terminated name
18     uint32_t      flash_base;    // Address within FLASH of image
19     uint32_t      mem_base;      // Address in memory where it executes
20     uint32_t      size;          // Length of image
21     uint32_t      entry_point;   // Execution entry point
22     uint32_t      data_length;   // Length of actual data
23     unsigned char _pad[256-(16+7*sizeof(uint32_t))];
24     uint32_t      desc_cksum;    // Checksum over image descriptor
25     uint32_t      file_cksum;    // Checksum over image data
26 };
27
28 struct fis_list {
29         struct fis_image_desc *img;
30         struct fis_list *next;
31 };
32
33 static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
34 module_param(directory, int, 0);
35
36 static inline int redboot_checksum(struct fis_image_desc *img)
37 {
38         /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
39         return 1;
40 }
41
42 static int parse_redboot_partitions(struct mtd_info *master,
43                              struct mtd_partition **pparts,
44                              unsigned long fis_origin)
45 {
46         int nrparts = 0;
47         struct fis_image_desc *buf;
48         struct mtd_partition *parts;
49         struct fis_list *fl = NULL, *tmp_fl;
50         int ret, i;
51         size_t retlen;
52         char *names;
53         char *nullname;
54         int namelen = 0;
55         int nulllen = 0;
56         int numslots;
57         unsigned long offset;
58 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
59         static char nullstring[] = "unallocated";
60 #endif
61
62         buf = vmalloc(master->erasesize);
63
64         if (!buf)
65                 return -ENOMEM;
66
67         if ( directory < 0 )
68                 offset = master->size + directory*master->erasesize;
69         else
70                 offset = directory*master->erasesize;
71
72         printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
73                master->name, offset);
74
75         ret = master->read(master, offset,
76                            master->erasesize, &retlen, (void *)buf);
77
78         if (ret)
79                 goto out;
80
81         if (retlen != master->erasesize) {
82                 ret = -EIO;
83                 goto out;
84         }
85
86         numslots = (master->erasesize / sizeof(struct fis_image_desc));
87         for (i = 0; i < numslots; i++) {
88                 if (!memcmp(buf[i].name, "FIS directory", 14)) {
89                         /* This is apparently the FIS directory entry for the
90                          * FIS directory itself.  The FIS directory size is
91                          * one erase block; if the buf[i].size field is
92                          * swab32(erasesize) then we know we are looking at
93                          * a byte swapped FIS directory - swap all the entries!
94                          * (NOTE: this is 'size' not 'data_length'; size is
95                          * the full size of the entry.)
96                          */
97
98                         /* RedBoot can combine the FIS directory and
99                            config partitions into a single eraseblock;
100                            we assume wrong-endian if either the swapped
101                            'size' matches the eraseblock size precisely,
102                            or if the swapped size actually fits in an
103                            eraseblock while the unswapped size doesn't. */
104                         if (swab32(buf[i].size) == master->erasesize ||
105                             (buf[i].size > master->erasesize
106                              && swab32(buf[i].size) < master->erasesize)) {
107                                 int j;
108                                 /* Update numslots based on actual FIS directory size */
109                                 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
110                                 for (j = 0; j < numslots; ++j) {
111
112                                         /* A single 0xff denotes a deleted entry.
113                                          * Two of them in a row is the end of the table.
114                                          */
115                                         if (buf[j].name[0] == 0xff) {
116                                                 if (buf[j].name[1] == 0xff) {
117                                                         break;
118                                                 } else {
119                                                         continue;
120                                                 }
121                                         }
122
123                                         /* The unsigned long fields were written with the
124                                          * wrong byte sex, name and pad have no byte sex.
125                                          */
126                                         swab32s(&buf[j].flash_base);
127                                         swab32s(&buf[j].mem_base);
128                                         swab32s(&buf[j].size);
129                                         swab32s(&buf[j].entry_point);
130                                         swab32s(&buf[j].data_length);
131                                         swab32s(&buf[j].desc_cksum);
132                                         swab32s(&buf[j].file_cksum);
133                                 }
134                         } else if (buf[i].size < master->erasesize) {
135                                 /* Update numslots based on actual FIS directory size */
136                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
137                         }
138                         break;
139                 }
140         }
141         if (i == numslots) {
142                 /* Didn't find it */
143                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
144                        master->name);
145                 ret = 0;
146                 goto out;
147         }
148
149         for (i = 0; i < numslots; i++) {
150                 struct fis_list *new_fl, **prev;
151
152                 if (buf[i].name[0] == 0xff) {
153                         if (buf[i].name[1] == 0xff) {
154                                 break;
155                         } else {
156                                 continue;
157                         }
158                 }
159                 if (!redboot_checksum(&buf[i]))
160                         break;
161
162                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
163                 namelen += strlen(buf[i].name)+1;
164                 if (!new_fl) {
165                         ret = -ENOMEM;
166                         goto out;
167                 }
168                 new_fl->img = &buf[i];
169                 if (fis_origin) {
170                         buf[i].flash_base -= fis_origin;
171                 } else {
172                         buf[i].flash_base &= master->size-1;
173                 }
174
175                 /* I'm sure the JFFS2 code has done me permanent damage.
176                  * I now think the following is _normal_
177                  */
178                 prev = &fl;
179                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
180                         prev = &(*prev)->next;
181                 new_fl->next = *prev;
182                 *prev = new_fl;
183
184                 nrparts++;
185         }
186 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
187         if (fl->img->flash_base) {
188                 nrparts++;
189                 nulllen = sizeof(nullstring);
190         }
191
192         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
193                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
194                         nrparts++;
195                         nulllen = sizeof(nullstring);
196                 }
197         }
198 #endif
199         parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
200
201         if (!parts) {
202                 ret = -ENOMEM;
203                 goto out;
204         }
205
206         nullname = (char *)&parts[nrparts];
207 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
208         if (nulllen > 0) {
209                 strcpy(nullname, nullstring);
210         }
211 #endif
212         names = nullname + nulllen;
213
214         i=0;
215
216 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
217         if (fl->img->flash_base) {
218                parts[0].name = nullname;
219                parts[0].size = fl->img->flash_base;
220                parts[0].offset = 0;
221                 i++;
222         }
223 #endif
224         for ( ; i<nrparts; i++) {
225                 parts[i].size = fl->img->size;
226                 parts[i].offset = fl->img->flash_base;
227                 parts[i].name = names;
228
229                 strcpy(names, fl->img->name);
230 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
231                 if (!memcmp(names, "RedBoot", 8) ||
232                                 !memcmp(names, "RedBoot config", 15) ||
233                                 !memcmp(names, "FIS directory", 14)) {
234                         parts[i].mask_flags = MTD_WRITEABLE;
235                 }
236 #endif
237                 names += strlen(names)+1;
238
239 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
240                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
241                         i++;
242                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
243                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
244                         parts[i].name = nullname;
245                 }
246 #endif
247                 tmp_fl = fl;
248                 fl = fl->next;
249                 kfree(tmp_fl);
250         }
251         ret = nrparts;
252         *pparts = parts;
253  out:
254         while (fl) {
255                 struct fis_list *old = fl;
256                 fl = fl->next;
257                 kfree(old);
258         }
259         vfree(buf);
260         return ret;
261 }
262
263 static struct mtd_part_parser redboot_parser = {
264         .owner = THIS_MODULE,
265         .parse_fn = parse_redboot_partitions,
266         .name = "RedBoot",
267 };
268
269 static int __init redboot_parser_init(void)
270 {
271         return register_mtd_parser(&redboot_parser);
272 }
273
274 static void __exit redboot_parser_exit(void)
275 {
276         deregister_mtd_parser(&redboot_parser);
277 }
278
279 module_init(redboot_parser_init);
280 module_exit(redboot_parser_exit);
281
282 MODULE_LICENSE("GPL");
283 MODULE_AUTHOR("Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>");
284 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");