1 /* 2 * c 2001 PPC 64 Team, IBM Corp 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * /dev/nvram driver for PPC64 10 * 11 * This perhaps should live in drivers/char 12 */ 13 14 15 #include <linux/types.h> 16 #include <linux/errno.h> 17 #include <linux/init.h> 18 #include <linux/spinlock.h> 19 #include <asm/uaccess.h> 20 #include <asm/nvram.h> 21 #include <asm/rtas.h> 22 #include <asm/prom.h> 23 #include <asm/machdep.h> 24 25 /* Max bytes to read/write in one go */ 26 #define NVRW_CNT 0x20 27 28 static unsigned int nvram_size; 29 static int nvram_fetch, nvram_store; 30 static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */ 31 static DEFINE_SPINLOCK(nvram_lock); 32 33 static long nvram_error_log_index = -1; 34 static long nvram_error_log_size = 0; 35 36 struct err_log_info { 37 int error_type; 38 unsigned int seq_num; 39 }; 40 #define NVRAM_MAX_REQ 2079 41 #define NVRAM_MIN_REQ 1055 42 43 #define NVRAM_LOG_PART_NAME "ibm,rtas-log" 44 45 static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index) 46 { 47 unsigned int i; 48 unsigned long len; 49 int done; 50 unsigned long flags; 51 char *p = buf; 52 53 54 if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE) 55 return -ENODEV; 56 57 if (*index >= nvram_size) 58 return 0; 59 60 i = *index; 61 if (i + count > nvram_size) 62 count = nvram_size - i; 63 64 spin_lock_irqsave(&nvram_lock, flags); 65 66 for (; count != 0; count -= len) { 67 len = count; 68 if (len > NVRW_CNT) 69 len = NVRW_CNT; 70 71 if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf), 72 len) != 0) || len != done) { 73 spin_unlock_irqrestore(&nvram_lock, flags); 74 return -EIO; 75 } 76 77 memcpy(p, nvram_buf, len); 78 79 p += len; 80 i += len; 81 } 82 83 spin_unlock_irqrestore(&nvram_lock, flags); 84 85 *index = i; 86 return p - buf; 87 } 88 89 static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index) 90 { 91 unsigned int i; 92 unsigned long len; 93 int done; 94 unsigned long flags; 95 const char *p = buf; 96 97 if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE) 98 return -ENODEV; 99 100 if (*index >= nvram_size) 101 return 0; 102 103 i = *index; 104 if (i + count > nvram_size) 105 count = nvram_size - i; 106 107 spin_lock_irqsave(&nvram_lock, flags); 108 109 for (; count != 0; count -= len) { 110 len = count; 111 if (len > NVRW_CNT) 112 len = NVRW_CNT; 113 114 memcpy(nvram_buf, p, len); 115 116 if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf), 117 len) != 0) || len != done) { 118 spin_unlock_irqrestore(&nvram_lock, flags); 119 return -EIO; 120 } 121 122 p += len; 123 i += len; 124 } 125 spin_unlock_irqrestore(&nvram_lock, flags); 126 127 *index = i; 128 return p - buf; 129 } 130 131 static ssize_t pSeries_nvram_get_size(void) 132 { 133 return nvram_size ? nvram_size : -ENODEV; 134 } 135 136 137 /* nvram_write_error_log 138 * 139 * We need to buffer the error logs into nvram to ensure that we have 140 * the failure information to decode. If we have a severe error there 141 * is no way to guarantee that the OS or the machine is in a state to 142 * get back to user land and write the error to disk. For example if 143 * the SCSI device driver causes a Machine Check by writing to a bad 144 * IO address, there is no way of guaranteeing that the device driver 145 * is in any state that is would also be able to write the error data 146 * captured to disk, thus we buffer it in NVRAM for analysis on the 147 * next boot. 148 * 149 * In NVRAM the partition containing the error log buffer will looks like: 150 * Header (in bytes): 151 * +-----------+----------+--------+------------+------------------+ 152 * | signature | checksum | length | name | data | 153 * |0 |1 |2 3|4 15|16 length-1| 154 * +-----------+----------+--------+------------+------------------+ 155 * 156 * The 'data' section would look like (in bytes): 157 * +--------------+------------+-----------------------------------+ 158 * | event_logged | sequence # | error log | 159 * |0 3|4 7|8 nvram_error_log_size-1| 160 * +--------------+------------+-----------------------------------+ 161 * 162 * event_logged: 0 if event has not been logged to syslog, 1 if it has 163 * sequence #: The unique sequence # for each event. (until it wraps) 164 * error log: The error log from event_scan 165 */ 166 int nvram_write_error_log(char * buff, int length, 167 unsigned int err_type, unsigned int error_log_cnt) 168 { 169 int rc; 170 loff_t tmp_index; 171 struct err_log_info info; 172 173 if (nvram_error_log_index == -1) { 174 return -ESPIPE; 175 } 176 177 if (length > nvram_error_log_size) { 178 length = nvram_error_log_size; 179 } 180 181 info.error_type = err_type; 182 info.seq_num = error_log_cnt; 183 184 tmp_index = nvram_error_log_index; 185 186 rc = ppc_md.nvram_write((char *)&info, sizeof(struct err_log_info), &tmp_index); 187 if (rc <= 0) { 188 printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc); 189 return rc; 190 } 191 192 rc = ppc_md.nvram_write(buff, length, &tmp_index); 193 if (rc <= 0) { 194 printk(KERN_ERR "nvram_write_error_log: Failed nvram_write (%d)\n", rc); 195 return rc; 196 } 197 198 return 0; 199 } 200 201 /* nvram_read_error_log 202 * 203 * Reads nvram for error log for at most 'length' 204 */ 205 int nvram_read_error_log(char * buff, int length, 206 unsigned int * err_type, unsigned int * error_log_cnt) 207 { 208 int rc; 209 loff_t tmp_index; 210 struct err_log_info info; 211 212 if (nvram_error_log_index == -1) 213 return -1; 214 215 if (length > nvram_error_log_size) 216 length = nvram_error_log_size; 217 218 tmp_index = nvram_error_log_index; 219 220 rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index); 221 if (rc <= 0) { 222 printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc); 223 return rc; 224 } 225 226 rc = ppc_md.nvram_read(buff, length, &tmp_index); 227 if (rc <= 0) { 228 printk(KERN_ERR "nvram_read_error_log: Failed nvram_read (%d)\n", rc); 229 return rc; 230 } 231 232 *error_log_cnt = info.seq_num; 233 *err_type = info.error_type; 234 235 return 0; 236 } 237 238 /* This doesn't actually zero anything, but it sets the event_logged 239 * word to tell that this event is safely in syslog. 240 */ 241 int nvram_clear_error_log(void) 242 { 243 loff_t tmp_index; 244 int clear_word = ERR_FLAG_ALREADY_LOGGED; 245 int rc; 246 247 if (nvram_error_log_index == -1) 248 return -1; 249 250 tmp_index = nvram_error_log_index; 251 252 rc = ppc_md.nvram_write((char *)&clear_word, sizeof(int), &tmp_index); 253 if (rc <= 0) { 254 printk(KERN_ERR "nvram_clear_error_log: Failed nvram_write (%d)\n", rc); 255 return rc; 256 } 257 258 return 0; 259 } 260 261 /* pseries_nvram_init_log_partition 262 * 263 * This will setup the partition we need for buffering the 264 * error logs and cleanup partitions if needed. 265 * 266 * The general strategy is the following: 267 * 1.) If there is log partition large enough then use it. 268 * 2.) If there is none large enough, search 269 * for a free partition that is large enough. 270 * 3.) If there is not a free partition large enough remove 271 * _all_ OS partitions and consolidate the space. 272 * 4.) Will first try getting a chunk that will satisfy the maximum 273 * error log size (NVRAM_MAX_REQ). 274 * 5.) If the max chunk cannot be allocated then try finding a chunk 275 * that will satisfy the minum needed (NVRAM_MIN_REQ). 276 */ 277 static int __init pseries_nvram_init_log_partition(void) 278 { 279 loff_t p; 280 int size; 281 282 /* Scan nvram for partitions */ 283 nvram_scan_partitions(); 284 285 /* Lookg for ours */ 286 p = nvram_find_partition(NVRAM_LOG_PART_NAME, NVRAM_SIG_OS, &size); 287 288 /* Found one but too small, remove it */ 289 if (p && size < NVRAM_MIN_REQ) { 290 pr_info("nvram: Found too small "NVRAM_LOG_PART_NAME" partition" 291 ",removing it..."); 292 nvram_remove_partition(NVRAM_LOG_PART_NAME, NVRAM_SIG_OS); 293 p = 0; 294 } 295 296 /* Create one if we didn't find */ 297 if (!p) { 298 p = nvram_create_partition(NVRAM_LOG_PART_NAME, NVRAM_SIG_OS, 299 NVRAM_MAX_REQ, NVRAM_MIN_REQ); 300 /* No room for it, try to get rid of any OS partition 301 * and try again 302 */ 303 if (p == -ENOSPC) { 304 pr_info("nvram: No room to create "NVRAM_LOG_PART_NAME 305 " partition, deleting all OS partitions..."); 306 nvram_remove_partition(NULL, NVRAM_SIG_OS); 307 p = nvram_create_partition(NVRAM_LOG_PART_NAME, 308 NVRAM_SIG_OS, NVRAM_MAX_REQ, 309 NVRAM_MIN_REQ); 310 } 311 } 312 313 if (p <= 0) { 314 pr_err("nvram: Failed to find or create "NVRAM_LOG_PART_NAME 315 " partition, err %d\n", (int)p); 316 return 0; 317 } 318 319 nvram_error_log_index = p; 320 nvram_error_log_size = nvram_get_partition_size(p) - 321 sizeof(struct err_log_info); 322 323 return 0; 324 } 325 machine_arch_initcall(pseries, pseries_nvram_init_log_partition); 326 327 int __init pSeries_nvram_init(void) 328 { 329 struct device_node *nvram; 330 const unsigned int *nbytes_p; 331 unsigned int proplen; 332 333 nvram = of_find_node_by_type(NULL, "nvram"); 334 if (nvram == NULL) 335 return -ENODEV; 336 337 nbytes_p = of_get_property(nvram, "#bytes", &proplen); 338 if (nbytes_p == NULL || proplen != sizeof(unsigned int)) { 339 of_node_put(nvram); 340 return -EIO; 341 } 342 343 nvram_size = *nbytes_p; 344 345 nvram_fetch = rtas_token("nvram-fetch"); 346 nvram_store = rtas_token("nvram-store"); 347 printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size); 348 of_node_put(nvram); 349 350 ppc_md.nvram_read = pSeries_nvram_read; 351 ppc_md.nvram_write = pSeries_nvram_write; 352 ppc_md.nvram_size = pSeries_nvram_get_size; 353 354 return 0; 355 } 356