1 /* 2 * arch/xtensa/kernel/setup.c 3 * 4 * This file is subject to the terms and conditions of the GNU General Public 5 * License. See the file "COPYING" in the main directory of this archive 6 * for more details. 7 * 8 * Copyright (C) 1995 Linus Torvalds 9 * Copyright (C) 2001 - 2005 Tensilica Inc. 10 * Copyright (C) 2014 - 2016 Cadence Design Systems Inc. 11 * 12 * Chris Zankel <chris@zankel.net> 13 * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com> 14 * Kevin Chea 15 * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca> 16 */ 17 18 #include <linux/errno.h> 19 #include <linux/init.h> 20 #include <linux/mm.h> 21 #include <linux/proc_fs.h> 22 #include <linux/screen_info.h> 23 #include <linux/bootmem.h> 24 #include <linux/kernel.h> 25 #include <linux/percpu.h> 26 #include <linux/cpu.h> 27 #include <linux/of.h> 28 #include <linux/of_fdt.h> 29 30 #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE) 31 # include <linux/console.h> 32 #endif 33 34 #ifdef CONFIG_PROC_FS 35 # include <linux/seq_file.h> 36 #endif 37 38 #include <asm/bootparam.h> 39 #include <asm/mmu_context.h> 40 #include <asm/pgtable.h> 41 #include <asm/processor.h> 42 #include <asm/timex.h> 43 #include <asm/platform.h> 44 #include <asm/page.h> 45 #include <asm/setup.h> 46 #include <asm/param.h> 47 #include <asm/smp.h> 48 #include <asm/sysmem.h> 49 50 #include <platform/hardware.h> 51 52 #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE) 53 struct screen_info screen_info = { 54 .orig_x = 0, 55 .orig_y = 24, 56 .orig_video_cols = 80, 57 .orig_video_lines = 24, 58 .orig_video_isVGA = 1, 59 .orig_video_points = 16, 60 }; 61 #endif 62 63 #ifdef CONFIG_BLK_DEV_INITRD 64 extern unsigned long initrd_start; 65 extern unsigned long initrd_end; 66 int initrd_is_mapped = 0; 67 extern int initrd_below_start_ok; 68 #endif 69 70 #ifdef CONFIG_OF 71 void *dtb_start = __dtb_start; 72 #endif 73 74 extern unsigned long loops_per_jiffy; 75 76 /* Command line specified as configuration option. */ 77 78 static char __initdata command_line[COMMAND_LINE_SIZE]; 79 80 #ifdef CONFIG_CMDLINE_BOOL 81 static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE; 82 #endif 83 84 /* 85 * Boot parameter parsing. 86 * 87 * The Xtensa port uses a list of variable-sized tags to pass data to 88 * the kernel. The first tag must be a BP_TAG_FIRST tag for the list 89 * to be recognised. The list is terminated with a zero-sized 90 * BP_TAG_LAST tag. 91 */ 92 93 typedef struct tagtable { 94 u32 tag; 95 int (*parse)(const bp_tag_t*); 96 } tagtable_t; 97 98 #define __tagtable(tag, fn) static tagtable_t __tagtable_##fn \ 99 __attribute__((used, section(".taglist"))) = { tag, fn } 100 101 /* parse current tag */ 102 103 static int __init parse_tag_mem(const bp_tag_t *tag) 104 { 105 struct bp_meminfo *mi = (struct bp_meminfo *)(tag->data); 106 107 if (mi->type != MEMORY_TYPE_CONVENTIONAL) 108 return -1; 109 110 return memblock_add(mi->start, mi->end - mi->start); 111 } 112 113 __tagtable(BP_TAG_MEMORY, parse_tag_mem); 114 115 #ifdef CONFIG_BLK_DEV_INITRD 116 117 static int __init parse_tag_initrd(const bp_tag_t* tag) 118 { 119 struct bp_meminfo *mi = (struct bp_meminfo *)(tag->data); 120 121 initrd_start = (unsigned long)__va(mi->start); 122 initrd_end = (unsigned long)__va(mi->end); 123 124 return 0; 125 } 126 127 __tagtable(BP_TAG_INITRD, parse_tag_initrd); 128 129 #endif /* CONFIG_BLK_DEV_INITRD */ 130 131 #ifdef CONFIG_OF 132 133 static int __init parse_tag_fdt(const bp_tag_t *tag) 134 { 135 dtb_start = __va(tag->data[0]); 136 return 0; 137 } 138 139 __tagtable(BP_TAG_FDT, parse_tag_fdt); 140 141 #endif /* CONFIG_OF */ 142 143 static int __init parse_tag_cmdline(const bp_tag_t* tag) 144 { 145 strlcpy(command_line, (char *)(tag->data), COMMAND_LINE_SIZE); 146 return 0; 147 } 148 149 __tagtable(BP_TAG_COMMAND_LINE, parse_tag_cmdline); 150 151 static int __init parse_bootparam(const bp_tag_t* tag) 152 { 153 extern tagtable_t __tagtable_begin, __tagtable_end; 154 tagtable_t *t; 155 156 /* Boot parameters must start with a BP_TAG_FIRST tag. */ 157 158 if (tag->id != BP_TAG_FIRST) { 159 printk(KERN_WARNING "Invalid boot parameters!\n"); 160 return 0; 161 } 162 163 tag = (bp_tag_t*)((unsigned long)tag + sizeof(bp_tag_t) + tag->size); 164 165 /* Parse all tags. */ 166 167 while (tag != NULL && tag->id != BP_TAG_LAST) { 168 for (t = &__tagtable_begin; t < &__tagtable_end; t++) { 169 if (tag->id == t->tag) { 170 t->parse(tag); 171 break; 172 } 173 } 174 if (t == &__tagtable_end) 175 printk(KERN_WARNING "Ignoring tag " 176 "0x%08x\n", tag->id); 177 tag = (bp_tag_t*)((unsigned long)(tag + 1) + tag->size); 178 } 179 180 return 0; 181 } 182 183 #ifdef CONFIG_OF 184 185 #if !XCHAL_HAVE_PTP_MMU || XCHAL_HAVE_SPANNING_WAY 186 unsigned long xtensa_kio_paddr = XCHAL_KIO_DEFAULT_PADDR; 187 EXPORT_SYMBOL(xtensa_kio_paddr); 188 189 static int __init xtensa_dt_io_area(unsigned long node, const char *uname, 190 int depth, void *data) 191 { 192 const __be32 *ranges; 193 int len; 194 195 if (depth > 1) 196 return 0; 197 198 if (!of_flat_dt_is_compatible(node, "simple-bus")) 199 return 0; 200 201 ranges = of_get_flat_dt_prop(node, "ranges", &len); 202 if (!ranges) 203 return 1; 204 if (len == 0) 205 return 1; 206 207 xtensa_kio_paddr = of_read_ulong(ranges+1, 1); 208 /* round down to nearest 256MB boundary */ 209 xtensa_kio_paddr &= 0xf0000000; 210 211 return 1; 212 } 213 #else 214 static int __init xtensa_dt_io_area(unsigned long node, const char *uname, 215 int depth, void *data) 216 { 217 return 1; 218 } 219 #endif 220 221 void __init early_init_dt_add_memory_arch(u64 base, u64 size) 222 { 223 size &= PAGE_MASK; 224 memblock_add(base, size); 225 } 226 227 void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align) 228 { 229 return __alloc_bootmem(size, align, 0); 230 } 231 232 void __init early_init_devtree(void *params) 233 { 234 early_init_dt_scan(params); 235 of_scan_flat_dt(xtensa_dt_io_area, NULL); 236 237 if (!command_line[0]) 238 strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE); 239 } 240 241 #endif /* CONFIG_OF */ 242 243 /* 244 * Initialize architecture. (Early stage) 245 */ 246 247 void __init init_arch(bp_tag_t *bp_start) 248 { 249 /* Parse boot parameters */ 250 251 if (bp_start) 252 parse_bootparam(bp_start); 253 254 #ifdef CONFIG_OF 255 early_init_devtree(dtb_start); 256 #endif 257 258 #ifdef CONFIG_CMDLINE_BOOL 259 if (!command_line[0]) 260 strlcpy(command_line, default_command_line, COMMAND_LINE_SIZE); 261 #endif 262 263 /* Early hook for platforms */ 264 265 platform_init(bp_start); 266 267 /* Initialize MMU. */ 268 269 init_mmu(); 270 } 271 272 /* 273 * Initialize system. Setup memory and reserve regions. 274 */ 275 276 extern char _end; 277 extern char _stext; 278 extern char _WindowVectors_text_start; 279 extern char _WindowVectors_text_end; 280 extern char _DebugInterruptVector_literal_start; 281 extern char _DebugInterruptVector_text_end; 282 extern char _KernelExceptionVector_literal_start; 283 extern char _KernelExceptionVector_text_end; 284 extern char _UserExceptionVector_literal_start; 285 extern char _UserExceptionVector_text_end; 286 extern char _DoubleExceptionVector_literal_start; 287 extern char _DoubleExceptionVector_text_end; 288 #if XCHAL_EXCM_LEVEL >= 2 289 extern char _Level2InterruptVector_text_start; 290 extern char _Level2InterruptVector_text_end; 291 #endif 292 #if XCHAL_EXCM_LEVEL >= 3 293 extern char _Level3InterruptVector_text_start; 294 extern char _Level3InterruptVector_text_end; 295 #endif 296 #if XCHAL_EXCM_LEVEL >= 4 297 extern char _Level4InterruptVector_text_start; 298 extern char _Level4InterruptVector_text_end; 299 #endif 300 #if XCHAL_EXCM_LEVEL >= 5 301 extern char _Level5InterruptVector_text_start; 302 extern char _Level5InterruptVector_text_end; 303 #endif 304 #if XCHAL_EXCM_LEVEL >= 6 305 extern char _Level6InterruptVector_text_start; 306 extern char _Level6InterruptVector_text_end; 307 #endif 308 #ifdef CONFIG_SMP 309 extern char _SecondaryResetVector_text_start; 310 extern char _SecondaryResetVector_text_end; 311 #endif 312 313 static inline int mem_reserve(unsigned long start, unsigned long end) 314 { 315 return memblock_reserve(start, end - start); 316 } 317 318 void __init setup_arch(char **cmdline_p) 319 { 320 strlcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); 321 *cmdline_p = command_line; 322 323 /* Reserve some memory regions */ 324 325 #ifdef CONFIG_BLK_DEV_INITRD 326 if (initrd_start < initrd_end) { 327 initrd_is_mapped = mem_reserve(__pa(initrd_start), 328 __pa(initrd_end)) == 0; 329 initrd_below_start_ok = 1; 330 } else { 331 initrd_start = 0; 332 } 333 #endif 334 335 mem_reserve(__pa(&_stext), __pa(&_end)); 336 337 #ifdef CONFIG_VECTORS_OFFSET 338 mem_reserve(__pa(&_WindowVectors_text_start), 339 __pa(&_WindowVectors_text_end)); 340 341 mem_reserve(__pa(&_DebugInterruptVector_literal_start), 342 __pa(&_DebugInterruptVector_text_end)); 343 344 mem_reserve(__pa(&_KernelExceptionVector_literal_start), 345 __pa(&_KernelExceptionVector_text_end)); 346 347 mem_reserve(__pa(&_UserExceptionVector_literal_start), 348 __pa(&_UserExceptionVector_text_end)); 349 350 mem_reserve(__pa(&_DoubleExceptionVector_literal_start), 351 __pa(&_DoubleExceptionVector_text_end)); 352 353 #if XCHAL_EXCM_LEVEL >= 2 354 mem_reserve(__pa(&_Level2InterruptVector_text_start), 355 __pa(&_Level2InterruptVector_text_end)); 356 #endif 357 #if XCHAL_EXCM_LEVEL >= 3 358 mem_reserve(__pa(&_Level3InterruptVector_text_start), 359 __pa(&_Level3InterruptVector_text_end)); 360 #endif 361 #if XCHAL_EXCM_LEVEL >= 4 362 mem_reserve(__pa(&_Level4InterruptVector_text_start), 363 __pa(&_Level4InterruptVector_text_end)); 364 #endif 365 #if XCHAL_EXCM_LEVEL >= 5 366 mem_reserve(__pa(&_Level5InterruptVector_text_start), 367 __pa(&_Level5InterruptVector_text_end)); 368 #endif 369 #if XCHAL_EXCM_LEVEL >= 6 370 mem_reserve(__pa(&_Level6InterruptVector_text_start), 371 __pa(&_Level6InterruptVector_text_end)); 372 #endif 373 374 #endif /* CONFIG_VECTORS_OFFSET */ 375 376 #ifdef CONFIG_SMP 377 mem_reserve(__pa(&_SecondaryResetVector_text_start), 378 __pa(&_SecondaryResetVector_text_end)); 379 #endif 380 parse_early_param(); 381 bootmem_init(); 382 383 unflatten_and_copy_device_tree(); 384 385 platform_setup(cmdline_p); 386 387 #ifdef CONFIG_SMP 388 smp_init_cpus(); 389 #endif 390 391 paging_init(); 392 zones_init(); 393 394 #ifdef CONFIG_VT 395 # if defined(CONFIG_VGA_CONSOLE) 396 conswitchp = &vga_con; 397 # elif defined(CONFIG_DUMMY_CONSOLE) 398 conswitchp = &dummy_con; 399 # endif 400 #endif 401 402 #ifdef CONFIG_PCI 403 platform_pcibios_init(); 404 #endif 405 } 406 407 static DEFINE_PER_CPU(struct cpu, cpu_data); 408 409 static int __init topology_init(void) 410 { 411 int i; 412 413 for_each_possible_cpu(i) { 414 struct cpu *cpu = &per_cpu(cpu_data, i); 415 cpu->hotpluggable = !!i; 416 register_cpu(cpu, i); 417 } 418 419 return 0; 420 } 421 subsys_initcall(topology_init); 422 423 void cpu_reset(void) 424 { 425 #if XCHAL_HAVE_PTP_MMU && IS_ENABLED(CONFIG_MMU) 426 local_irq_disable(); 427 /* 428 * We have full MMU: all autoload ways, ways 7, 8 and 9 of DTLB must 429 * be flushed. 430 * Way 4 is not currently used by linux. 431 * Ways 5 and 6 shall not be touched on MMUv2 as they are hardwired. 432 * Way 5 shall be flushed and way 6 shall be set to identity mapping 433 * on MMUv3. 434 */ 435 local_flush_tlb_all(); 436 invalidate_page_directory(); 437 #if XCHAL_HAVE_SPANNING_WAY 438 /* MMU v3 */ 439 { 440 unsigned long vaddr = (unsigned long)cpu_reset; 441 unsigned long paddr = __pa(vaddr); 442 unsigned long tmpaddr = vaddr + SZ_512M; 443 unsigned long tmp0, tmp1, tmp2, tmp3; 444 445 /* 446 * Find a place for the temporary mapping. It must not be 447 * in the same 512MB region with vaddr or paddr, otherwise 448 * there may be multihit exception either on entry to the 449 * temporary mapping, or on entry to the identity mapping. 450 * (512MB is the biggest page size supported by TLB.) 451 */ 452 while (((tmpaddr ^ paddr) & -SZ_512M) == 0) 453 tmpaddr += SZ_512M; 454 455 /* Invalidate mapping in the selected temporary area */ 456 if (itlb_probe(tmpaddr) & 0x8) 457 invalidate_itlb_entry(itlb_probe(tmpaddr)); 458 if (itlb_probe(tmpaddr + PAGE_SIZE) & 0x8) 459 invalidate_itlb_entry(itlb_probe(tmpaddr + PAGE_SIZE)); 460 461 /* 462 * Map two consecutive pages starting at the physical address 463 * of this function to the temporary mapping area. 464 */ 465 write_itlb_entry(__pte((paddr & PAGE_MASK) | 466 _PAGE_HW_VALID | 467 _PAGE_HW_EXEC | 468 _PAGE_CA_BYPASS), 469 tmpaddr & PAGE_MASK); 470 write_itlb_entry(__pte(((paddr & PAGE_MASK) + PAGE_SIZE) | 471 _PAGE_HW_VALID | 472 _PAGE_HW_EXEC | 473 _PAGE_CA_BYPASS), 474 (tmpaddr & PAGE_MASK) + PAGE_SIZE); 475 476 /* Reinitialize TLB */ 477 __asm__ __volatile__ ("movi %0, 1f\n\t" 478 "movi %3, 2f\n\t" 479 "add %0, %0, %4\n\t" 480 "add %3, %3, %5\n\t" 481 "jx %0\n" 482 /* 483 * No literal, data or stack access 484 * below this point 485 */ 486 "1:\n\t" 487 /* Initialize *tlbcfg */ 488 "movi %0, 0\n\t" 489 "wsr %0, itlbcfg\n\t" 490 "wsr %0, dtlbcfg\n\t" 491 /* Invalidate TLB way 5 */ 492 "movi %0, 4\n\t" 493 "movi %1, 5\n" 494 "1:\n\t" 495 "iitlb %1\n\t" 496 "idtlb %1\n\t" 497 "add %1, %1, %6\n\t" 498 "addi %0, %0, -1\n\t" 499 "bnez %0, 1b\n\t" 500 /* Initialize TLB way 6 */ 501 "movi %0, 7\n\t" 502 "addi %1, %9, 3\n\t" 503 "addi %2, %9, 6\n" 504 "1:\n\t" 505 "witlb %1, %2\n\t" 506 "wdtlb %1, %2\n\t" 507 "add %1, %1, %7\n\t" 508 "add %2, %2, %7\n\t" 509 "addi %0, %0, -1\n\t" 510 "bnez %0, 1b\n\t" 511 /* Jump to identity mapping */ 512 "jx %3\n" 513 "2:\n\t" 514 /* Complete way 6 initialization */ 515 "witlb %1, %2\n\t" 516 "wdtlb %1, %2\n\t" 517 /* Invalidate temporary mapping */ 518 "sub %0, %9, %7\n\t" 519 "iitlb %0\n\t" 520 "add %0, %0, %8\n\t" 521 "iitlb %0" 522 : "=&a"(tmp0), "=&a"(tmp1), "=&a"(tmp2), 523 "=&a"(tmp3) 524 : "a"(tmpaddr - vaddr), 525 "a"(paddr - vaddr), 526 "a"(SZ_128M), "a"(SZ_512M), 527 "a"(PAGE_SIZE), 528 "a"((tmpaddr + SZ_512M) & PAGE_MASK) 529 : "memory"); 530 } 531 #endif 532 #endif 533 __asm__ __volatile__ ("movi a2, 0\n\t" 534 "wsr a2, icountlevel\n\t" 535 "movi a2, 0\n\t" 536 "wsr a2, icount\n\t" 537 #if XCHAL_NUM_IBREAK > 0 538 "wsr a2, ibreakenable\n\t" 539 #endif 540 #if XCHAL_HAVE_LOOPS 541 "wsr a2, lcount\n\t" 542 #endif 543 "movi a2, 0x1f\n\t" 544 "wsr a2, ps\n\t" 545 "isync\n\t" 546 "jx %0\n\t" 547 : 548 : "a" (XCHAL_RESET_VECTOR_VADDR) 549 : "a2"); 550 for (;;) 551 ; 552 } 553 554 void machine_restart(char * cmd) 555 { 556 platform_restart(); 557 } 558 559 void machine_halt(void) 560 { 561 platform_halt(); 562 while (1); 563 } 564 565 void machine_power_off(void) 566 { 567 platform_power_off(); 568 while (1); 569 } 570 #ifdef CONFIG_PROC_FS 571 572 /* 573 * Display some core information through /proc/cpuinfo. 574 */ 575 576 static int 577 c_show(struct seq_file *f, void *slot) 578 { 579 /* high-level stuff */ 580 seq_printf(f, "CPU count\t: %u\n" 581 "CPU list\t: %*pbl\n" 582 "vendor_id\t: Tensilica\n" 583 "model\t\t: Xtensa " XCHAL_HW_VERSION_NAME "\n" 584 "core ID\t\t: " XCHAL_CORE_ID "\n" 585 "build ID\t: 0x%x\n" 586 "byte order\t: %s\n" 587 "cpu MHz\t\t: %lu.%02lu\n" 588 "bogomips\t: %lu.%02lu\n", 589 num_online_cpus(), 590 cpumask_pr_args(cpu_online_mask), 591 XCHAL_BUILD_UNIQUE_ID, 592 XCHAL_HAVE_BE ? "big" : "little", 593 ccount_freq/1000000, 594 (ccount_freq/10000) % 100, 595 loops_per_jiffy/(500000/HZ), 596 (loops_per_jiffy/(5000/HZ)) % 100); 597 598 seq_printf(f,"flags\t\t: " 599 #if XCHAL_HAVE_NMI 600 "nmi " 601 #endif 602 #if XCHAL_HAVE_DEBUG 603 "debug " 604 # if XCHAL_HAVE_OCD 605 "ocd " 606 # endif 607 #endif 608 #if XCHAL_HAVE_DENSITY 609 "density " 610 #endif 611 #if XCHAL_HAVE_BOOLEANS 612 "boolean " 613 #endif 614 #if XCHAL_HAVE_LOOPS 615 "loop " 616 #endif 617 #if XCHAL_HAVE_NSA 618 "nsa " 619 #endif 620 #if XCHAL_HAVE_MINMAX 621 "minmax " 622 #endif 623 #if XCHAL_HAVE_SEXT 624 "sext " 625 #endif 626 #if XCHAL_HAVE_CLAMPS 627 "clamps " 628 #endif 629 #if XCHAL_HAVE_MAC16 630 "mac16 " 631 #endif 632 #if XCHAL_HAVE_MUL16 633 "mul16 " 634 #endif 635 #if XCHAL_HAVE_MUL32 636 "mul32 " 637 #endif 638 #if XCHAL_HAVE_MUL32_HIGH 639 "mul32h " 640 #endif 641 #if XCHAL_HAVE_FP 642 "fpu " 643 #endif 644 #if XCHAL_HAVE_S32C1I 645 "s32c1i " 646 #endif 647 "\n"); 648 649 /* Registers. */ 650 seq_printf(f,"physical aregs\t: %d\n" 651 "misc regs\t: %d\n" 652 "ibreak\t\t: %d\n" 653 "dbreak\t\t: %d\n", 654 XCHAL_NUM_AREGS, 655 XCHAL_NUM_MISC_REGS, 656 XCHAL_NUM_IBREAK, 657 XCHAL_NUM_DBREAK); 658 659 660 /* Interrupt. */ 661 seq_printf(f,"num ints\t: %d\n" 662 "ext ints\t: %d\n" 663 "int levels\t: %d\n" 664 "timers\t\t: %d\n" 665 "debug level\t: %d\n", 666 XCHAL_NUM_INTERRUPTS, 667 XCHAL_NUM_EXTINTERRUPTS, 668 XCHAL_NUM_INTLEVELS, 669 XCHAL_NUM_TIMERS, 670 XCHAL_DEBUGLEVEL); 671 672 /* Cache */ 673 seq_printf(f,"icache line size: %d\n" 674 "icache ways\t: %d\n" 675 "icache size\t: %d\n" 676 "icache flags\t: " 677 #if XCHAL_ICACHE_LINE_LOCKABLE 678 "lock " 679 #endif 680 "\n" 681 "dcache line size: %d\n" 682 "dcache ways\t: %d\n" 683 "dcache size\t: %d\n" 684 "dcache flags\t: " 685 #if XCHAL_DCACHE_IS_WRITEBACK 686 "writeback " 687 #endif 688 #if XCHAL_DCACHE_LINE_LOCKABLE 689 "lock " 690 #endif 691 "\n", 692 XCHAL_ICACHE_LINESIZE, 693 XCHAL_ICACHE_WAYS, 694 XCHAL_ICACHE_SIZE, 695 XCHAL_DCACHE_LINESIZE, 696 XCHAL_DCACHE_WAYS, 697 XCHAL_DCACHE_SIZE); 698 699 return 0; 700 } 701 702 /* 703 * We show only CPU #0 info. 704 */ 705 static void * 706 c_start(struct seq_file *f, loff_t *pos) 707 { 708 return (*pos == 0) ? (void *)1 : NULL; 709 } 710 711 static void * 712 c_next(struct seq_file *f, void *v, loff_t *pos) 713 { 714 return NULL; 715 } 716 717 static void 718 c_stop(struct seq_file *f, void *v) 719 { 720 } 721 722 const struct seq_operations cpuinfo_op = 723 { 724 .start = c_start, 725 .next = c_next, 726 .stop = c_stop, 727 .show = c_show, 728 }; 729 730 #endif /* CONFIG_PROC_FS */ 731