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1/*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/seq_file.h>
10#include <linux/fs.h>
11#include <linux/delay.h>
12#include <linux/root_dev.h>
13#include <linux/clk.h>
14#include <linux/clk-provider.h>
15#include <linux/clocksource.h>
16#include <linux/console.h>
17#include <linux/module.h>
18#include <linux/cpu.h>
19#include <linux/of_fdt.h>
20#include <linux/of.h>
21#include <linux/cache.h>
22#include <asm/sections.h>
23#include <asm/arcregs.h>
24#include <asm/tlb.h>
25#include <asm/setup.h>
26#include <asm/page.h>
27#include <asm/irq.h>
28#include <asm/unwind.h>
29#include <asm/mach_desc.h>
30#include <asm/smp.h>
31
32#define FIX_PTR(x) __asm__ __volatile__(";" : "+r"(x))
33
34unsigned int intr_to_DE_cnt;
35
36/* Part of U-boot ABI: see head.S */
37int __initdata uboot_tag;
38char __initdata *uboot_arg;
39
40const struct machine_desc *machine_desc;
41
42struct task_struct *_current_task[NR_CPUS]; /* For stack switching */
43
44struct cpuinfo_arc cpuinfo_arc700[NR_CPUS];
45
46static const struct id_to_str arc_cpu_rel[] = {
47#ifdef CONFIG_ISA_ARCOMPACT
48 { 0x34, "R4.10"},
49 { 0x35, "R4.11"},
50#else
51 { 0x51, "R2.0" },
52 { 0x52, "R2.1" },
53 { 0x53, "R3.0" },
54 { 0x54, "R3.10a" },
55#endif
56 { 0x00, NULL }
57};
58
59static const struct id_to_str arc_cpu_nm[] = {
60#ifdef CONFIG_ISA_ARCOMPACT
61 { 0x20, "ARC 600" },
62 { 0x30, "ARC 770" }, /* 750 identified seperately */
63#else
64 { 0x40, "ARC EM" },
65 { 0x50, "ARC HS38" },
66 { 0x54, "ARC HS48" },
67#endif
68 { 0x00, "Unknown" }
69};
70
71static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
72{
73 if (is_isa_arcompact()) {
74 struct bcr_iccm_arcompact iccm;
75 struct bcr_dccm_arcompact dccm;
76
77 READ_BCR(ARC_REG_ICCM_BUILD, iccm);
78 if (iccm.ver) {
79 cpu->iccm.sz = 4096 << iccm.sz; /* 8K to 512K */
80 cpu->iccm.base_addr = iccm.base << 16;
81 }
82
83 READ_BCR(ARC_REG_DCCM_BUILD, dccm);
84 if (dccm.ver) {
85 unsigned long base;
86 cpu->dccm.sz = 2048 << dccm.sz; /* 2K to 256K */
87
88 base = read_aux_reg(ARC_REG_DCCM_BASE_BUILD);
89 cpu->dccm.base_addr = base & ~0xF;
90 }
91 } else {
92 struct bcr_iccm_arcv2 iccm;
93 struct bcr_dccm_arcv2 dccm;
94 unsigned long region;
95
96 READ_BCR(ARC_REG_ICCM_BUILD, iccm);
97 if (iccm.ver) {
98 cpu->iccm.sz = 256 << iccm.sz00; /* 512B to 16M */
99 if (iccm.sz00 == 0xF && iccm.sz01 > 0)
100 cpu->iccm.sz <<= iccm.sz01;
101
102 region = read_aux_reg(ARC_REG_AUX_ICCM);
103 cpu->iccm.base_addr = region & 0xF0000000;
104 }
105
106 READ_BCR(ARC_REG_DCCM_BUILD, dccm);
107 if (dccm.ver) {
108 cpu->dccm.sz = 256 << dccm.sz0;
109 if (dccm.sz0 == 0xF && dccm.sz1 > 0)
110 cpu->dccm.sz <<= dccm.sz1;
111
112 region = read_aux_reg(ARC_REG_AUX_DCCM);
113 cpu->dccm.base_addr = region & 0xF0000000;
114 }
115 }
116}
117
118static void read_arc_build_cfg_regs(void)
119{
120 struct bcr_timer timer;
121 struct bcr_generic bcr;
122 struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
123 const struct id_to_str *tbl;
124 struct bcr_isa_arcv2 isa;
125
126 FIX_PTR(cpu);
127
128 READ_BCR(AUX_IDENTITY, cpu->core);
129
130 for (tbl = &arc_cpu_rel[0]; tbl->id != 0; tbl++) {
131 if (cpu->core.family == tbl->id) {
132 cpu->details = tbl->str;
133 break;
134 }
135 }
136
137 for (tbl = &arc_cpu_nm[0]; tbl->id != 0; tbl++) {
138 if ((cpu->core.family & 0xF4) == tbl->id)
139 break;
140 }
141 cpu->name = tbl->str;
142
143 READ_BCR(ARC_REG_TIMERS_BCR, timer);
144 cpu->extn.timer0 = timer.t0;
145 cpu->extn.timer1 = timer.t1;
146 cpu->extn.rtc = timer.rtc;
147
148 cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);
149
150 READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);
151
152 cpu->extn.norm = read_aux_reg(ARC_REG_NORM_BCR) > 1 ? 1 : 0; /* 2,3 */
153 cpu->extn.barrel = read_aux_reg(ARC_REG_BARREL_BCR) > 1 ? 1 : 0; /* 2,3 */
154 cpu->extn.swap = read_aux_reg(ARC_REG_SWAP_BCR) ? 1 : 0; /* 1,3 */
155 cpu->extn.crc = read_aux_reg(ARC_REG_CRC_BCR) ? 1 : 0;
156 cpu->extn.minmax = read_aux_reg(ARC_REG_MIXMAX_BCR) > 1 ? 1 : 0; /* 2 */
157 cpu->extn.swape = (cpu->core.family >= 0x34) ? 1 :
158 IS_ENABLED(CONFIG_ARC_HAS_SWAPE);
159
160 READ_BCR(ARC_REG_XY_MEM_BCR, cpu->extn_xymem);
161
162 /* Read CCM BCRs for boot reporting even if not enabled in Kconfig */
163 read_decode_ccm_bcr(cpu);
164
165 read_decode_mmu_bcr();
166 read_decode_cache_bcr();
167
168 if (is_isa_arcompact()) {
169 struct bcr_fp_arcompact sp, dp;
170 struct bcr_bpu_arcompact bpu;
171
172 READ_BCR(ARC_REG_FP_BCR, sp);
173 READ_BCR(ARC_REG_DPFP_BCR, dp);
174 cpu->extn.fpu_sp = sp.ver ? 1 : 0;
175 cpu->extn.fpu_dp = dp.ver ? 1 : 0;
176
177 READ_BCR(ARC_REG_BPU_BCR, bpu);
178 cpu->bpu.ver = bpu.ver;
179 cpu->bpu.full = bpu.fam ? 1 : 0;
180 if (bpu.ent) {
181 cpu->bpu.num_cache = 256 << (bpu.ent - 1);
182 cpu->bpu.num_pred = 256 << (bpu.ent - 1);
183 }
184 } else {
185 struct bcr_fp_arcv2 spdp;
186 struct bcr_bpu_arcv2 bpu;
187
188 READ_BCR(ARC_REG_FP_V2_BCR, spdp);
189 cpu->extn.fpu_sp = spdp.sp ? 1 : 0;
190 cpu->extn.fpu_dp = spdp.dp ? 1 : 0;
191
192 READ_BCR(ARC_REG_BPU_BCR, bpu);
193 cpu->bpu.ver = bpu.ver;
194 cpu->bpu.full = bpu.ft;
195 cpu->bpu.num_cache = 256 << bpu.bce;
196 cpu->bpu.num_pred = 2048 << bpu.pte;
197
198 if (cpu->core.family >= 0x54) {
199 unsigned int exec_ctrl;
200
201 READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
202 cpu->extn.dual_enb = !(exec_ctrl & 1);
203
204 /* dual issue always present for this core */
205 cpu->extn.dual = 1;
206 }
207 }
208
209 READ_BCR(ARC_REG_AP_BCR, bcr);
210 cpu->extn.ap = bcr.ver ? 1 : 0;
211
212 READ_BCR(ARC_REG_SMART_BCR, bcr);
213 cpu->extn.smart = bcr.ver ? 1 : 0;
214
215 READ_BCR(ARC_REG_RTT_BCR, bcr);
216 cpu->extn.rtt = bcr.ver ? 1 : 0;
217
218 cpu->extn.debug = cpu->extn.ap | cpu->extn.smart | cpu->extn.rtt;
219
220 READ_BCR(ARC_REG_ISA_CFG_BCR, isa);
221
222 /* some hacks for lack of feature BCR info in old ARC700 cores */
223 if (is_isa_arcompact()) {
224 if (!isa.ver) /* ISA BCR absent, use Kconfig info */
225 cpu->isa.atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
226 else {
227 /* ARC700_BUILD only has 2 bits of isa info */
228 struct bcr_generic bcr = *(struct bcr_generic *)&isa;
229 cpu->isa.atomic = bcr.info & 1;
230 }
231
232 cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
233
234 /* there's no direct way to distinguish 750 vs. 770 */
235 if (unlikely(cpu->core.family < 0x34 || cpu->mmu.ver < 3))
236 cpu->name = "ARC750";
237 } else {
238 cpu->isa = isa;
239 }
240}
241
242static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
243{
244 struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
245 struct bcr_identity *core = &cpu->core;
246 int i, n = 0;
247
248 FIX_PTR(cpu);
249
250 n += scnprintf(buf + n, len - n,
251 "\nIDENTITY\t: ARCVER [%#02x] ARCNUM [%#02x] CHIPID [%#4x]\n",
252 core->family, core->cpu_id, core->chip_id);
253
254 n += scnprintf(buf + n, len - n, "processor [%d]\t: %s %s (%s ISA) %s%s%s\n",
255 cpu_id, cpu->name, cpu->details,
256 is_isa_arcompact() ? "ARCompact" : "ARCv2",
257 IS_AVAIL1(cpu->isa.be, "[Big-Endian]"),
258 IS_AVAIL3(cpu->extn.dual, cpu->extn.dual_enb, " Dual-Issue "));
259
260 n += scnprintf(buf + n, len - n, "Timers\t\t: %s%s%s%s%s%s\nISA Extn\t: ",
261 IS_AVAIL1(cpu->extn.timer0, "Timer0 "),
262 IS_AVAIL1(cpu->extn.timer1, "Timer1 "),
263 IS_AVAIL2(cpu->extn.rtc, "RTC [UP 64-bit] ", CONFIG_ARC_TIMERS_64BIT),
264 IS_AVAIL2(cpu->extn.gfrc, "GFRC [SMP 64-bit] ", CONFIG_ARC_TIMERS_64BIT));
265
266 n += i = scnprintf(buf + n, len - n, "%s%s%s%s%s",
267 IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
268 IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
269 IS_AVAIL1(cpu->isa.unalign, "unalign (not used)"));
270
271 if (i)
272 n += scnprintf(buf + n, len - n, "\n\t\t: ");
273
274 if (cpu->extn_mpy.ver) {
275 if (cpu->extn_mpy.ver <= 0x2) { /* ARCompact */
276 n += scnprintf(buf + n, len - n, "mpy ");
277 } else {
278 int opt = 2; /* stock MPY/MPYH */
279
280 if (cpu->extn_mpy.dsp) /* OPT 7-9 */
281 opt = cpu->extn_mpy.dsp + 6;
282
283 n += scnprintf(buf + n, len - n, "mpy[opt %d] ", opt);
284 }
285 }
286
287 n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s%s%s\n",
288 IS_AVAIL1(cpu->isa.div_rem, "div_rem "),
289 IS_AVAIL1(cpu->extn.norm, "norm "),
290 IS_AVAIL1(cpu->extn.barrel, "barrel-shift "),
291 IS_AVAIL1(cpu->extn.swap, "swap "),
292 IS_AVAIL1(cpu->extn.minmax, "minmax "),
293 IS_AVAIL1(cpu->extn.crc, "crc "),
294 IS_AVAIL2(cpu->extn.swape, "swape", CONFIG_ARC_HAS_SWAPE));
295
296 if (cpu->bpu.ver)
297 n += scnprintf(buf + n, len - n,
298 "BPU\t\t: %s%s match, cache:%d, Predict Table:%d",
299 IS_AVAIL1(cpu->bpu.full, "full"),
300 IS_AVAIL1(!cpu->bpu.full, "partial"),
301 cpu->bpu.num_cache, cpu->bpu.num_pred);
302
303 if (is_isa_arcv2()) {
304 struct bcr_lpb lpb;
305
306 READ_BCR(ARC_REG_LPB_BUILD, lpb);
307 if (lpb.ver) {
308 unsigned int ctl;
309 ctl = read_aux_reg(ARC_REG_LPB_CTRL);
310
311 n += scnprintf(buf + n, len - n, " Loop Buffer:%d %s",
312 lpb.entries,
313 IS_DISABLED_RUN(!ctl));
314 }
315 }
316
317 n += scnprintf(buf + n, len - n, "\n");
318 return buf;
319}
320
321static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
322{
323 int n = 0;
324 struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
325
326 FIX_PTR(cpu);
327
328 n += scnprintf(buf + n, len - n, "Vector Table\t: %#x\n", cpu->vec_base);
329
330 if (cpu->extn.fpu_sp || cpu->extn.fpu_dp)
331 n += scnprintf(buf + n, len - n, "FPU\t\t: %s%s\n",
332 IS_AVAIL1(cpu->extn.fpu_sp, "SP "),
333 IS_AVAIL1(cpu->extn.fpu_dp, "DP "));
334
335 if (cpu->extn.debug)
336 n += scnprintf(buf + n, len - n, "DEBUG\t\t: %s%s%s\n",
337 IS_AVAIL1(cpu->extn.ap, "ActionPoint "),
338 IS_AVAIL1(cpu->extn.smart, "smaRT "),
339 IS_AVAIL1(cpu->extn.rtt, "RTT "));
340
341 if (cpu->dccm.sz || cpu->iccm.sz)
342 n += scnprintf(buf + n, len - n, "Extn [CCM]\t: DCCM @ %x, %d KB / ICCM: @ %x, %d KB\n",
343 cpu->dccm.base_addr, TO_KB(cpu->dccm.sz),
344 cpu->iccm.base_addr, TO_KB(cpu->iccm.sz));
345
346 if (is_isa_arcv2()) {
347
348 /* Error Protection: ECC/Parity */
349 struct bcr_erp erp;
350 READ_BCR(ARC_REG_ERP_BUILD, erp);
351
352 if (erp.ver) {
353 struct ctl_erp ctl;
354 READ_BCR(ARC_REG_ERP_CTRL, ctl);
355
356 /* inverted bits: 0 means enabled */
357 n += scnprintf(buf + n, len - n, "Extn [ECC]\t: %s%s%s%s%s%s\n",
358 IS_AVAIL3(erp.ic, !ctl.dpi, "IC "),
359 IS_AVAIL3(erp.dc, !ctl.dpd, "DC "),
360 IS_AVAIL3(erp.mmu, !ctl.mpd, "MMU "));
361 }
362 }
363
364 n += scnprintf(buf + n, len - n, "OS ABI [v%d]\t: %s\n",
365 EF_ARC_OSABI_CURRENT >> 8,
366 EF_ARC_OSABI_CURRENT == EF_ARC_OSABI_V3 ?
367 "no-legacy-syscalls" : "64-bit data any register aligned");
368
369 return buf;
370}
371
372static void arc_chk_core_config(void)
373{
374 struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
375 int saved = 0, present = 0;
376 char *opt_nm = NULL;
377
378 if (!cpu->extn.timer0)
379 panic("Timer0 is not present!\n");
380
381 if (!cpu->extn.timer1)
382 panic("Timer1 is not present!\n");
383
384#ifdef CONFIG_ARC_HAS_DCCM
385 /*
386 * DCCM can be arbit placed in hardware.
387 * Make sure it's placement/sz matches what Linux is built with
388 */
389 if ((unsigned int)__arc_dccm_base != cpu->dccm.base_addr)
390 panic("Linux built with incorrect DCCM Base address\n");
391
392 if (CONFIG_ARC_DCCM_SZ != cpu->dccm.sz)
393 panic("Linux built with incorrect DCCM Size\n");
394#endif
395
396#ifdef CONFIG_ARC_HAS_ICCM
397 if (CONFIG_ARC_ICCM_SZ != cpu->iccm.sz)
398 panic("Linux built with incorrect ICCM Size\n");
399#endif
400
401 /*
402 * FP hardware/software config sanity
403 * -If hardware present, kernel needs to save/restore FPU state
404 * -If not, it will crash trying to save/restore the non-existant regs
405 */
406
407 if (is_isa_arcompact()) {
408 opt_nm = "CONFIG_ARC_FPU_SAVE_RESTORE";
409 saved = IS_ENABLED(CONFIG_ARC_FPU_SAVE_RESTORE);
410
411 /* only DPDP checked since SP has no arch visible regs */
412 present = cpu->extn.fpu_dp;
413 } else {
414 opt_nm = "CONFIG_ARC_HAS_ACCL_REGS";
415 saved = IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS);
416
417 /* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */
418 present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp;
419 }
420
421 if (present && !saved)
422 pr_warn("Enable %s for working apps\n", opt_nm);
423 else if (!present && saved)
424 panic("Disable %s, hardware NOT present\n", opt_nm);
425}
426
427/*
428 * Initialize and setup the processor core
429 * This is called by all the CPUs thus should not do special case stuff
430 * such as only for boot CPU etc
431 */
432
433void setup_processor(void)
434{
435 char str[512];
436 int cpu_id = smp_processor_id();
437
438 read_arc_build_cfg_regs();
439 arc_init_IRQ();
440
441 pr_info("%s", arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));
442
443 arc_mmu_init();
444 arc_cache_init();
445
446 pr_info("%s", arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));
447 pr_info("%s", arc_platform_smp_cpuinfo());
448
449 arc_chk_core_config();
450}
451
452static inline int is_kernel(unsigned long addr)
453{
454 if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
455 return 1;
456 return 0;
457}
458
459void __init setup_arch(char **cmdline_p)
460{
461#ifdef CONFIG_ARC_UBOOT_SUPPORT
462 /* make sure that uboot passed pointer to cmdline/dtb is valid */
463 if (uboot_tag && is_kernel((unsigned long)uboot_arg))
464 panic("Invalid uboot arg\n");
465
466 /* See if u-boot passed an external Device Tree blob */
467 machine_desc = setup_machine_fdt(uboot_arg); /* uboot_tag == 2 */
468 if (!machine_desc)
469#endif
470 {
471 /* No, so try the embedded one */
472 machine_desc = setup_machine_fdt(__dtb_start);
473 if (!machine_desc)
474 panic("Embedded DT invalid\n");
475
476 /*
477 * If we are here, it is established that @uboot_arg didn't
478 * point to DT blob. Instead if u-boot says it is cmdline,
479 * append to embedded DT cmdline.
480 * setup_machine_fdt() would have populated @boot_command_line
481 */
482 if (uboot_tag == 1) {
483 /* Ensure a whitespace between the 2 cmdlines */
484 strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
485 strlcat(boot_command_line, uboot_arg,
486 COMMAND_LINE_SIZE);
487 }
488 }
489
490 /* Save unparsed command line copy for /proc/cmdline */
491 *cmdline_p = boot_command_line;
492
493 /* To force early parsing of things like mem=xxx */
494 parse_early_param();
495
496 /* Platform/board specific: e.g. early console registration */
497 if (machine_desc->init_early)
498 machine_desc->init_early();
499
500 smp_init_cpus();
501
502 setup_processor();
503 setup_arch_memory();
504
505 /* copy flat DT out of .init and then unflatten it */
506 unflatten_and_copy_device_tree();
507
508 /* Can be issue if someone passes cmd line arg "ro"
509 * But that is unlikely so keeping it as it is
510 */
511 root_mountflags &= ~MS_RDONLY;
512
513#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
514 conswitchp = &dummy_con;
515#endif
516
517 arc_unwind_init();
518}
519
520/*
521 * Called from start_kernel() - boot CPU only
522 */
523void __init time_init(void)
524{
525 of_clk_init(NULL);
526 timer_probe();
527}
528
529static int __init customize_machine(void)
530{
531 if (machine_desc->init_machine)
532 machine_desc->init_machine();
533
534 return 0;
535}
536arch_initcall(customize_machine);
537
538static int __init init_late_machine(void)
539{
540 if (machine_desc->init_late)
541 machine_desc->init_late();
542
543 return 0;
544}
545late_initcall(init_late_machine);
546/*
547 * Get CPU information for use by the procfs.
548 */
549
550#define cpu_to_ptr(c) ((void *)(0xFFFF0000 | (unsigned int)(c)))
551#define ptr_to_cpu(p) (~0xFFFF0000UL & (unsigned int)(p))
552
553static int show_cpuinfo(struct seq_file *m, void *v)
554{
555 char *str;
556 int cpu_id = ptr_to_cpu(v);
557 struct device *cpu_dev = get_cpu_device(cpu_id);
558 struct clk *cpu_clk;
559 unsigned long freq = 0;
560
561 if (!cpu_online(cpu_id)) {
562 seq_printf(m, "processor [%d]\t: Offline\n", cpu_id);
563 goto done;
564 }
565
566 str = (char *)__get_free_page(GFP_KERNEL);
567 if (!str)
568 goto done;
569
570 seq_printf(m, arc_cpu_mumbojumbo(cpu_id, str, PAGE_SIZE));
571
572 cpu_clk = clk_get(cpu_dev, NULL);
573 if (IS_ERR(cpu_clk)) {
574 seq_printf(m, "CPU speed \t: Cannot get clock for processor [%d]\n",
575 cpu_id);
576 } else {
577 freq = clk_get_rate(cpu_clk);
578 }
579 if (freq)
580 seq_printf(m, "CPU speed\t: %lu.%02lu Mhz\n",
581 freq / 1000000, (freq / 10000) % 100);
582
583 seq_printf(m, "Bogo MIPS\t: %lu.%02lu\n",
584 loops_per_jiffy / (500000 / HZ),
585 (loops_per_jiffy / (5000 / HZ)) % 100);
586
587 seq_printf(m, arc_mmu_mumbojumbo(cpu_id, str, PAGE_SIZE));
588 seq_printf(m, arc_cache_mumbojumbo(cpu_id, str, PAGE_SIZE));
589 seq_printf(m, arc_extn_mumbojumbo(cpu_id, str, PAGE_SIZE));
590 seq_printf(m, arc_platform_smp_cpuinfo());
591
592 free_page((unsigned long)str);
593done:
594 seq_printf(m, "\n");
595
596 return 0;
597}
598
599static void *c_start(struct seq_file *m, loff_t *pos)
600{
601 /*
602 * Callback returns cpu-id to iterator for show routine, NULL to stop.
603 * However since NULL is also a valid cpu-id (0), we use a round-about
604 * way to pass it w/o having to kmalloc/free a 2 byte string.
605 * Encode cpu-id as 0xFFcccc, which is decoded by show routine.
606 */
607 return *pos < nr_cpu_ids ? cpu_to_ptr(*pos) : NULL;
608}
609
610static void *c_next(struct seq_file *m, void *v, loff_t *pos)
611{
612 ++*pos;
613 return c_start(m, pos);
614}
615
616static void c_stop(struct seq_file *m, void *v)
617{
618}
619
620const struct seq_operations cpuinfo_op = {
621 .start = c_start,
622 .next = c_next,
623 .stop = c_stop,
624 .show = show_cpuinfo
625};
626
627static DEFINE_PER_CPU(struct cpu, cpu_topology);
628
629static int __init topology_init(void)
630{
631 int cpu;
632
633 for_each_present_cpu(cpu)
634 register_cpu(&per_cpu(cpu_topology, cpu), cpu);
635
636 return 0;
637}
638
639subsys_initcall(topology_init);