| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * CMOS/NV-RAM driver for Linux |
| 4 | * |
| 5 | * Copyright (C) 1997 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de> |
| 6 | * idea by and with help from Richard Jelinek <rj@suse.de> |
| 7 | * Portions copyright (c) 2001,2002 Sun Microsystems (thockin@sun.com) |
| 8 | * |
| 9 | * This driver allows you to access the contents of the non-volatile memory in |
| 10 | * the mc146818rtc.h real-time clock. This chip is built into all PCs and into |
| 11 | * many Atari machines. In the former it's called "CMOS-RAM", in the latter |
| 12 | * "NVRAM" (NV stands for non-volatile). |
| 13 | * |
| 14 | * The data are supplied as a (seekable) character device, /dev/nvram. The |
| 15 | * size of this file is dependent on the controller. The usual size is 114, |
| 16 | * the number of freely available bytes in the memory (i.e., not used by the |
| 17 | * RTC itself). |
| 18 | * |
| 19 | * Checksums over the NVRAM contents are managed by this driver. In case of a |
| 20 | * bad checksum, reads and writes return -EIO. The checksum can be initialized |
| 21 | * to a sane state either by ioctl(NVRAM_INIT) (clear whole NVRAM) or |
| 22 | * ioctl(NVRAM_SETCKS) (doesn't change contents, just makes checksum valid |
| 23 | * again; use with care!) |
| 24 | * |
| 25 | * 1.1 Cesar Barros: SMP locking fixes |
| 26 | * added changelog |
| 27 | * 1.2 Erik Gilling: Cobalt Networks support |
| 28 | * Tim Hockin: general cleanup, Cobalt support |
| 29 | * 1.3 Wim Van Sebroeck: convert PRINT_PROC to seq_file |
| 30 | */ |
| 31 | |
| 32 | #define NVRAM_VERSION "1.3" |
| 33 | |
| 34 | #include <linux/module.h> |
| 35 | #include <linux/nvram.h> |
| 36 | #include <linux/types.h> |
| 37 | #include <linux/errno.h> |
| 38 | #include <linux/miscdevice.h> |
| 39 | #include <linux/ioport.h> |
| 40 | #include <linux/fcntl.h> |
| 41 | #include <linux/mc146818rtc.h> |
| 42 | #include <linux/init.h> |
| 43 | #include <linux/proc_fs.h> |
| 44 | #include <linux/seq_file.h> |
| 45 | #include <linux/slab.h> |
| 46 | #include <linux/spinlock.h> |
| 47 | #include <linux/io.h> |
| 48 | #include <linux/uaccess.h> |
| 49 | #include <linux/mutex.h> |
| 50 | #include <linux/pagemap.h> |
| 51 | |
| 52 | #ifdef CONFIG_PPC |
| 53 | #include <asm/nvram.h> |
| 54 | #endif |
| 55 | |
| 56 | static DEFINE_MUTEX(nvram_mutex); |
| 57 | static DEFINE_SPINLOCK(nvram_state_lock); |
| 58 | static int nvram_open_cnt; /* #times opened */ |
| 59 | static int nvram_open_mode; /* special open modes */ |
| 60 | static ssize_t nvram_size; |
| 61 | #define NVRAM_WRITE 1 /* opened for writing (exclusive) */ |
| 62 | #define NVRAM_EXCL 2 /* opened with O_EXCL */ |
| 63 | |
| 64 | #ifdef CONFIG_X86 |
| 65 | /* |
| 66 | * These functions are provided to be called internally or by other parts of |
| 67 | * the kernel. It's up to the caller to ensure correct checksum before reading |
| 68 | * or after writing (needs to be done only once). |
| 69 | * |
| 70 | * It is worth noting that these functions all access bytes of general |
| 71 | * purpose memory in the NVRAM - that is to say, they all add the |
| 72 | * NVRAM_FIRST_BYTE offset. Pass them offsets into NVRAM as if you did not |
| 73 | * know about the RTC cruft. |
| 74 | */ |
| 75 | |
| 76 | #define NVRAM_BYTES (128 - NVRAM_FIRST_BYTE) |
| 77 | |
| 78 | /* Note that *all* calls to CMOS_READ and CMOS_WRITE must be done with |
| 79 | * rtc_lock held. Due to the index-port/data-port design of the RTC, we |
| 80 | * don't want two different things trying to get to it at once. (e.g. the |
| 81 | * periodic 11 min sync from kernel/time/ntp.c vs. this driver.) |
| 82 | */ |
| 83 | |
| 84 | static unsigned char __nvram_read_byte(int i) |
| 85 | { |
| 86 | return CMOS_READ(NVRAM_FIRST_BYTE + i); |
| 87 | } |
| 88 | |
| 89 | static unsigned char pc_nvram_read_byte(int i) |
| 90 | { |
| 91 | unsigned long flags; |
| 92 | unsigned char c; |
| 93 | |
| 94 | spin_lock_irqsave(&rtc_lock, flags); |
| 95 | c = __nvram_read_byte(i); |
| 96 | spin_unlock_irqrestore(&rtc_lock, flags); |
| 97 | return c; |
| 98 | } |
| 99 | |
| 100 | /* This races nicely with trying to read with checksum checking (nvram_read) */ |
| 101 | static void __nvram_write_byte(unsigned char c, int i) |
| 102 | { |
| 103 | CMOS_WRITE(c, NVRAM_FIRST_BYTE + i); |
| 104 | } |
| 105 | |
| 106 | static void pc_nvram_write_byte(unsigned char c, int i) |
| 107 | { |
| 108 | unsigned long flags; |
| 109 | |
| 110 | spin_lock_irqsave(&rtc_lock, flags); |
| 111 | __nvram_write_byte(c, i); |
| 112 | spin_unlock_irqrestore(&rtc_lock, flags); |
| 113 | } |
| 114 | |
| 115 | /* On PCs, the checksum is built only over bytes 2..31 */ |
| 116 | #define PC_CKS_RANGE_START 2 |
| 117 | #define PC_CKS_RANGE_END 31 |
| 118 | #define PC_CKS_LOC 32 |
| 119 | |
| 120 | static int __nvram_check_checksum(void) |
| 121 | { |
| 122 | int i; |
| 123 | unsigned short sum = 0; |
| 124 | unsigned short expect; |
| 125 | |
| 126 | for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i) |
| 127 | sum += __nvram_read_byte(i); |
| 128 | expect = __nvram_read_byte(PC_CKS_LOC)<<8 | |
| 129 | __nvram_read_byte(PC_CKS_LOC+1); |
| 130 | return (sum & 0xffff) == expect; |
| 131 | } |
| 132 | |
| 133 | static void __nvram_set_checksum(void) |
| 134 | { |
| 135 | int i; |
| 136 | unsigned short sum = 0; |
| 137 | |
| 138 | for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i) |
| 139 | sum += __nvram_read_byte(i); |
| 140 | __nvram_write_byte(sum >> 8, PC_CKS_LOC); |
| 141 | __nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1); |
| 142 | } |
| 143 | |
| 144 | static long pc_nvram_set_checksum(void) |
| 145 | { |
| 146 | spin_lock_irq(&rtc_lock); |
| 147 | __nvram_set_checksum(); |
| 148 | spin_unlock_irq(&rtc_lock); |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | static long pc_nvram_initialize(void) |
| 153 | { |
| 154 | ssize_t i; |
| 155 | |
| 156 | spin_lock_irq(&rtc_lock); |
| 157 | for (i = 0; i < NVRAM_BYTES; ++i) |
| 158 | __nvram_write_byte(0, i); |
| 159 | __nvram_set_checksum(); |
| 160 | spin_unlock_irq(&rtc_lock); |
| 161 | return 0; |
| 162 | } |
| 163 | |
| 164 | static ssize_t pc_nvram_get_size(void) |
| 165 | { |
| 166 | return NVRAM_BYTES; |
| 167 | } |
| 168 | |
| 169 | static ssize_t pc_nvram_read(char *buf, size_t count, loff_t *ppos) |
| 170 | { |
| 171 | char *p = buf; |
| 172 | loff_t i; |
| 173 | |
| 174 | spin_lock_irq(&rtc_lock); |
| 175 | if (!__nvram_check_checksum()) { |
| 176 | spin_unlock_irq(&rtc_lock); |
| 177 | return -EIO; |
| 178 | } |
| 179 | for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p) |
| 180 | *p = __nvram_read_byte(i); |
| 181 | spin_unlock_irq(&rtc_lock); |
| 182 | |
| 183 | *ppos = i; |
| 184 | return p - buf; |
| 185 | } |
| 186 | |
| 187 | static ssize_t pc_nvram_write(char *buf, size_t count, loff_t *ppos) |
| 188 | { |
| 189 | char *p = buf; |
| 190 | loff_t i; |
| 191 | |
| 192 | spin_lock_irq(&rtc_lock); |
| 193 | if (!__nvram_check_checksum()) { |
| 194 | spin_unlock_irq(&rtc_lock); |
| 195 | return -EIO; |
| 196 | } |
| 197 | for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p) |
| 198 | __nvram_write_byte(*p, i); |
| 199 | __nvram_set_checksum(); |
| 200 | spin_unlock_irq(&rtc_lock); |
| 201 | |
| 202 | *ppos = i; |
| 203 | return p - buf; |
| 204 | } |
| 205 | |
| 206 | const struct nvram_ops arch_nvram_ops = { |
| 207 | .read = pc_nvram_read, |
| 208 | .write = pc_nvram_write, |
| 209 | .read_byte = pc_nvram_read_byte, |
| 210 | .write_byte = pc_nvram_write_byte, |
| 211 | .get_size = pc_nvram_get_size, |
| 212 | .set_checksum = pc_nvram_set_checksum, |
| 213 | .initialize = pc_nvram_initialize, |
| 214 | }; |
| 215 | EXPORT_SYMBOL(arch_nvram_ops); |
| 216 | #endif /* CONFIG_X86 */ |
| 217 | |
| 218 | /* |
| 219 | * The are the file operation function for user access to /dev/nvram |
| 220 | */ |
| 221 | |
| 222 | static loff_t nvram_misc_llseek(struct file *file, loff_t offset, int origin) |
| 223 | { |
| 224 | return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE, |
| 225 | nvram_size); |
| 226 | } |
| 227 | |
| 228 | static ssize_t nvram_misc_read(struct file *file, char __user *buf, |
| 229 | size_t count, loff_t *ppos) |
| 230 | { |
| 231 | char *tmp; |
| 232 | ssize_t ret; |
| 233 | |
| 234 | |
| 235 | if (*ppos >= nvram_size) |
| 236 | return 0; |
| 237 | |
| 238 | count = min_t(size_t, count, nvram_size - *ppos); |
| 239 | count = min_t(size_t, count, PAGE_SIZE); |
| 240 | |
| 241 | tmp = kmalloc(count, GFP_KERNEL); |
| 242 | if (!tmp) |
| 243 | return -ENOMEM; |
| 244 | |
| 245 | ret = nvram_read(tmp, count, ppos); |
| 246 | if (ret <= 0) |
| 247 | goto out; |
| 248 | |
| 249 | if (copy_to_user(buf, tmp, ret)) { |
| 250 | *ppos -= ret; |
| 251 | ret = -EFAULT; |
| 252 | } |
| 253 | |
| 254 | out: |
| 255 | kfree(tmp); |
| 256 | return ret; |
| 257 | } |
| 258 | |
| 259 | static ssize_t nvram_misc_write(struct file *file, const char __user *buf, |
| 260 | size_t count, loff_t *ppos) |
| 261 | { |
| 262 | char *tmp; |
| 263 | ssize_t ret; |
| 264 | |
| 265 | if (*ppos >= nvram_size) |
| 266 | return 0; |
| 267 | |
| 268 | count = min_t(size_t, count, nvram_size - *ppos); |
| 269 | count = min_t(size_t, count, PAGE_SIZE); |
| 270 | |
| 271 | tmp = memdup_user(buf, count); |
| 272 | if (IS_ERR(tmp)) |
| 273 | return PTR_ERR(tmp); |
| 274 | |
| 275 | ret = nvram_write(tmp, count, ppos); |
| 276 | kfree(tmp); |
| 277 | return ret; |
| 278 | } |
| 279 | |
| 280 | static long nvram_misc_ioctl(struct file *file, unsigned int cmd, |
| 281 | unsigned long arg) |
| 282 | { |
| 283 | long ret = -ENOTTY; |
| 284 | |
| 285 | switch (cmd) { |
| 286 | #ifdef CONFIG_PPC |
| 287 | case OBSOLETE_PMAC_NVRAM_GET_OFFSET: |
| 288 | pr_warn("nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n"); |
| 289 | fallthrough; |
| 290 | case IOC_NVRAM_GET_OFFSET: |
| 291 | ret = -EINVAL; |
| 292 | #ifdef CONFIG_PPC_PMAC |
| 293 | if (machine_is(powermac)) { |
| 294 | int part, offset; |
| 295 | |
| 296 | if (copy_from_user(&part, (void __user *)arg, |
| 297 | sizeof(part)) != 0) |
| 298 | return -EFAULT; |
| 299 | if (part < pmac_nvram_OF || part > pmac_nvram_NR) |
| 300 | return -EINVAL; |
| 301 | offset = pmac_get_partition(part); |
| 302 | if (offset < 0) |
| 303 | return -EINVAL; |
| 304 | if (copy_to_user((void __user *)arg, |
| 305 | &offset, sizeof(offset)) != 0) |
| 306 | return -EFAULT; |
| 307 | ret = 0; |
| 308 | } |
| 309 | #endif |
| 310 | break; |
| 311 | #ifdef CONFIG_PPC32 |
| 312 | case IOC_NVRAM_SYNC: |
| 313 | if (ppc_md.nvram_sync != NULL) { |
| 314 | mutex_lock(&nvram_mutex); |
| 315 | ppc_md.nvram_sync(); |
| 316 | mutex_unlock(&nvram_mutex); |
| 317 | } |
| 318 | ret = 0; |
| 319 | break; |
| 320 | #endif |
| 321 | #elif defined(CONFIG_X86) || defined(CONFIG_M68K) |
| 322 | case NVRAM_INIT: |
| 323 | /* initialize NVRAM contents and checksum */ |
| 324 | if (!capable(CAP_SYS_ADMIN)) |
| 325 | return -EACCES; |
| 326 | |
| 327 | if (arch_nvram_ops.initialize != NULL) { |
| 328 | mutex_lock(&nvram_mutex); |
| 329 | ret = arch_nvram_ops.initialize(); |
| 330 | mutex_unlock(&nvram_mutex); |
| 331 | } |
| 332 | break; |
| 333 | case NVRAM_SETCKS: |
| 334 | /* just set checksum, contents unchanged (maybe useful after |
| 335 | * checksum garbaged somehow...) */ |
| 336 | if (!capable(CAP_SYS_ADMIN)) |
| 337 | return -EACCES; |
| 338 | |
| 339 | if (arch_nvram_ops.set_checksum != NULL) { |
| 340 | mutex_lock(&nvram_mutex); |
| 341 | ret = arch_nvram_ops.set_checksum(); |
| 342 | mutex_unlock(&nvram_mutex); |
| 343 | } |
| 344 | break; |
| 345 | #endif /* CONFIG_X86 || CONFIG_M68K */ |
| 346 | } |
| 347 | return ret; |
| 348 | } |
| 349 | |
| 350 | static int nvram_misc_open(struct inode *inode, struct file *file) |
| 351 | { |
| 352 | spin_lock(&nvram_state_lock); |
| 353 | |
| 354 | /* Prevent multiple readers/writers if desired. */ |
| 355 | if ((nvram_open_cnt && (file->f_flags & O_EXCL)) || |
| 356 | (nvram_open_mode & NVRAM_EXCL)) { |
| 357 | spin_unlock(&nvram_state_lock); |
| 358 | return -EBUSY; |
| 359 | } |
| 360 | |
| 361 | #if defined(CONFIG_X86) || defined(CONFIG_M68K) |
| 362 | /* Prevent multiple writers if the set_checksum ioctl is implemented. */ |
| 363 | if ((arch_nvram_ops.set_checksum != NULL) && |
| 364 | (file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE)) { |
| 365 | spin_unlock(&nvram_state_lock); |
| 366 | return -EBUSY; |
| 367 | } |
| 368 | #endif |
| 369 | |
| 370 | if (file->f_flags & O_EXCL) |
| 371 | nvram_open_mode |= NVRAM_EXCL; |
| 372 | if (file->f_mode & FMODE_WRITE) |
| 373 | nvram_open_mode |= NVRAM_WRITE; |
| 374 | nvram_open_cnt++; |
| 375 | |
| 376 | spin_unlock(&nvram_state_lock); |
| 377 | |
| 378 | return 0; |
| 379 | } |
| 380 | |
| 381 | static int nvram_misc_release(struct inode *inode, struct file *file) |
| 382 | { |
| 383 | spin_lock(&nvram_state_lock); |
| 384 | |
| 385 | nvram_open_cnt--; |
| 386 | |
| 387 | /* if only one instance is open, clear the EXCL bit */ |
| 388 | if (nvram_open_mode & NVRAM_EXCL) |
| 389 | nvram_open_mode &= ~NVRAM_EXCL; |
| 390 | if (file->f_mode & FMODE_WRITE) |
| 391 | nvram_open_mode &= ~NVRAM_WRITE; |
| 392 | |
| 393 | spin_unlock(&nvram_state_lock); |
| 394 | |
| 395 | return 0; |
| 396 | } |
| 397 | |
| 398 | #if defined(CONFIG_X86) && defined(CONFIG_PROC_FS) |
| 399 | static const char * const floppy_types[] = { |
| 400 | "none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M", |
| 401 | "3.5'' 2.88M", "3.5'' 2.88M" |
| 402 | }; |
| 403 | |
| 404 | static const char * const gfx_types[] = { |
| 405 | "EGA, VGA, ... (with BIOS)", |
| 406 | "CGA (40 cols)", |
| 407 | "CGA (80 cols)", |
| 408 | "monochrome", |
| 409 | }; |
| 410 | |
| 411 | static void pc_nvram_proc_read(unsigned char *nvram, struct seq_file *seq, |
| 412 | void *offset) |
| 413 | { |
| 414 | int checksum; |
| 415 | int type; |
| 416 | |
| 417 | spin_lock_irq(&rtc_lock); |
| 418 | checksum = __nvram_check_checksum(); |
| 419 | spin_unlock_irq(&rtc_lock); |
| 420 | |
| 421 | seq_printf(seq, "Checksum status: %svalid\n", checksum ? "" : "not "); |
| 422 | |
| 423 | seq_printf(seq, "# floppies : %d\n", |
| 424 | (nvram[6] & 1) ? (nvram[6] >> 6) + 1 : 0); |
| 425 | seq_printf(seq, "Floppy 0 type : "); |
| 426 | type = nvram[2] >> 4; |
| 427 | if (type < ARRAY_SIZE(floppy_types)) |
| 428 | seq_printf(seq, "%s\n", floppy_types[type]); |
| 429 | else |
| 430 | seq_printf(seq, "%d (unknown)\n", type); |
| 431 | seq_printf(seq, "Floppy 1 type : "); |
| 432 | type = nvram[2] & 0x0f; |
| 433 | if (type < ARRAY_SIZE(floppy_types)) |
| 434 | seq_printf(seq, "%s\n", floppy_types[type]); |
| 435 | else |
| 436 | seq_printf(seq, "%d (unknown)\n", type); |
| 437 | |
| 438 | seq_printf(seq, "HD 0 type : "); |
| 439 | type = nvram[4] >> 4; |
| 440 | if (type) |
| 441 | seq_printf(seq, "%02x\n", type == 0x0f ? nvram[11] : type); |
| 442 | else |
| 443 | seq_printf(seq, "none\n"); |
| 444 | |
| 445 | seq_printf(seq, "HD 1 type : "); |
| 446 | type = nvram[4] & 0x0f; |
| 447 | if (type) |
| 448 | seq_printf(seq, "%02x\n", type == 0x0f ? nvram[12] : type); |
| 449 | else |
| 450 | seq_printf(seq, "none\n"); |
| 451 | |
| 452 | seq_printf(seq, "HD type 48 data: %d/%d/%d C/H/S, precomp %d, lz %d\n", |
| 453 | nvram[18] | (nvram[19] << 8), |
| 454 | nvram[20], nvram[25], |
| 455 | nvram[21] | (nvram[22] << 8), nvram[23] | (nvram[24] << 8)); |
| 456 | seq_printf(seq, "HD type 49 data: %d/%d/%d C/H/S, precomp %d, lz %d\n", |
| 457 | nvram[39] | (nvram[40] << 8), |
| 458 | nvram[41], nvram[46], |
| 459 | nvram[42] | (nvram[43] << 8), nvram[44] | (nvram[45] << 8)); |
| 460 | |
| 461 | seq_printf(seq, "DOS base memory: %d kB\n", nvram[7] | (nvram[8] << 8)); |
| 462 | seq_printf(seq, "Extended memory: %d kB (configured), %d kB (tested)\n", |
| 463 | nvram[9] | (nvram[10] << 8), nvram[34] | (nvram[35] << 8)); |
| 464 | |
| 465 | seq_printf(seq, "Gfx adapter : %s\n", |
| 466 | gfx_types[(nvram[6] >> 4) & 3]); |
| 467 | |
| 468 | seq_printf(seq, "FPU : %sinstalled\n", |
| 469 | (nvram[6] & 2) ? "" : "not "); |
| 470 | |
| 471 | return; |
| 472 | } |
| 473 | |
| 474 | static int nvram_proc_read(struct seq_file *seq, void *offset) |
| 475 | { |
| 476 | unsigned char contents[NVRAM_BYTES]; |
| 477 | int i = 0; |
| 478 | |
| 479 | spin_lock_irq(&rtc_lock); |
| 480 | for (i = 0; i < NVRAM_BYTES; ++i) |
| 481 | contents[i] = __nvram_read_byte(i); |
| 482 | spin_unlock_irq(&rtc_lock); |
| 483 | |
| 484 | pc_nvram_proc_read(contents, seq, offset); |
| 485 | |
| 486 | return 0; |
| 487 | } |
| 488 | #endif /* CONFIG_X86 && CONFIG_PROC_FS */ |
| 489 | |
| 490 | static const struct file_operations nvram_misc_fops = { |
| 491 | .owner = THIS_MODULE, |
| 492 | .llseek = nvram_misc_llseek, |
| 493 | .read = nvram_misc_read, |
| 494 | .write = nvram_misc_write, |
| 495 | .unlocked_ioctl = nvram_misc_ioctl, |
| 496 | .open = nvram_misc_open, |
| 497 | .release = nvram_misc_release, |
| 498 | }; |
| 499 | |
| 500 | static struct miscdevice nvram_misc = { |
| 501 | NVRAM_MINOR, |
| 502 | "nvram", |
| 503 | &nvram_misc_fops, |
| 504 | }; |
| 505 | |
| 506 | static int __init nvram_module_init(void) |
| 507 | { |
| 508 | int ret; |
| 509 | |
| 510 | nvram_size = nvram_get_size(); |
| 511 | if (nvram_size < 0) |
| 512 | return nvram_size; |
| 513 | |
| 514 | ret = misc_register(&nvram_misc); |
| 515 | if (ret) { |
| 516 | pr_err("nvram: can't misc_register on minor=%d\n", NVRAM_MINOR); |
| 517 | return ret; |
| 518 | } |
| 519 | |
| 520 | #if defined(CONFIG_X86) && defined(CONFIG_PROC_FS) |
| 521 | if (!proc_create_single("driver/nvram", 0, NULL, nvram_proc_read)) { |
| 522 | pr_err("nvram: can't create /proc/driver/nvram\n"); |
| 523 | misc_deregister(&nvram_misc); |
| 524 | return -ENOMEM; |
| 525 | } |
| 526 | #endif |
| 527 | |
| 528 | pr_info("Non-volatile memory driver v" NVRAM_VERSION "\n"); |
| 529 | return 0; |
| 530 | } |
| 531 | |
| 532 | static void __exit nvram_module_exit(void) |
| 533 | { |
| 534 | #if defined(CONFIG_X86) && defined(CONFIG_PROC_FS) |
| 535 | remove_proc_entry("driver/nvram", NULL); |
| 536 | #endif |
| 537 | misc_deregister(&nvram_misc); |
| 538 | } |
| 539 | |
| 540 | module_init(nvram_module_init); |
| 541 | module_exit(nvram_module_exit); |
| 542 | |
| 543 | MODULE_DESCRIPTION("CMOS/NV-RAM driver for Linux"); |
| 544 | MODULE_LICENSE("GPL"); |
| 545 | MODULE_ALIAS_MISCDEV(NVRAM_MINOR); |
| 546 | MODULE_ALIAS("devname:nvram"); |