e1c647490f00e91069671f5aeb9871830cb9be83
[linux-2.6-microblaze.git] / arch / arc / kernel / setup.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4  */
5
6 #include <linux/seq_file.h>
7 #include <linux/fs.h>
8 #include <linux/delay.h>
9 #include <linux/root_dev.h>
10 #include <linux/clk.h>
11 #include <linux/clk-provider.h>
12 #include <linux/clocksource.h>
13 #include <linux/console.h>
14 #include <linux/module.h>
15 #include <linux/cpu.h>
16 #include <linux/of_fdt.h>
17 #include <linux/of.h>
18 #include <linux/cache.h>
19 #include <uapi/linux/mount.h>
20 #include <asm/sections.h>
21 #include <asm/arcregs.h>
22 #include <asm/tlb.h>
23 #include <asm/setup.h>
24 #include <asm/page.h>
25 #include <asm/irq.h>
26 #include <asm/unwind.h>
27 #include <asm/mach_desc.h>
28 #include <asm/smp.h>
29
30 #define FIX_PTR(x)  __asm__ __volatile__(";" : "+r"(x))
31
32 unsigned int intr_to_DE_cnt;
33
34 /* Part of U-boot ABI: see head.S */
35 int __initdata uboot_tag;
36 int __initdata uboot_magic;
37 char __initdata *uboot_arg;
38
39 const struct machine_desc *machine_desc;
40
41 struct task_struct *_current_task[NR_CPUS];     /* For stack switching */
42
43 struct cpuinfo_arc cpuinfo_arc700[NR_CPUS];
44
45 static const struct id_to_str arc_legacy_rel[] = {
46         /* ID.ARCVER,   Release */
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 #endif
55         { 0x00,         NULL   }
56 };
57
58 static const struct id_to_str arc_cpu_rel[] = {
59         /* UARCH.MAJOR, Release */
60         {  0,           "R3.10a"},
61         {  1,           "R3.50a"},
62         {  0xFF,        NULL   }
63 };
64
65 static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
66 {
67         if (is_isa_arcompact()) {
68                 struct bcr_iccm_arcompact iccm;
69                 struct bcr_dccm_arcompact dccm;
70
71                 READ_BCR(ARC_REG_ICCM_BUILD, iccm);
72                 if (iccm.ver) {
73                         cpu->iccm.sz = 4096 << iccm.sz; /* 8K to 512K */
74                         cpu->iccm.base_addr = iccm.base << 16;
75                 }
76
77                 READ_BCR(ARC_REG_DCCM_BUILD, dccm);
78                 if (dccm.ver) {
79                         unsigned long base;
80                         cpu->dccm.sz = 2048 << dccm.sz; /* 2K to 256K */
81
82                         base = read_aux_reg(ARC_REG_DCCM_BASE_BUILD);
83                         cpu->dccm.base_addr = base & ~0xF;
84                 }
85         } else {
86                 struct bcr_iccm_arcv2 iccm;
87                 struct bcr_dccm_arcv2 dccm;
88                 unsigned long region;
89
90                 READ_BCR(ARC_REG_ICCM_BUILD, iccm);
91                 if (iccm.ver) {
92                         cpu->iccm.sz = 256 << iccm.sz00;        /* 512B to 16M */
93                         if (iccm.sz00 == 0xF && iccm.sz01 > 0)
94                                 cpu->iccm.sz <<= iccm.sz01;
95
96                         region = read_aux_reg(ARC_REG_AUX_ICCM);
97                         cpu->iccm.base_addr = region & 0xF0000000;
98                 }
99
100                 READ_BCR(ARC_REG_DCCM_BUILD, dccm);
101                 if (dccm.ver) {
102                         cpu->dccm.sz = 256 << dccm.sz0;
103                         if (dccm.sz0 == 0xF && dccm.sz1 > 0)
104                                 cpu->dccm.sz <<= dccm.sz1;
105
106                         region = read_aux_reg(ARC_REG_AUX_DCCM);
107                         cpu->dccm.base_addr = region & 0xF0000000;
108                 }
109         }
110 }
111
112 static void decode_arc_core(struct cpuinfo_arc *cpu)
113 {
114         struct bcr_uarch_build_arcv2 uarch;
115         const struct id_to_str *tbl;
116
117         /*
118          * Up until (including) the first core4 release (0x54) things were
119          * simple: AUX IDENTITY.ARCVER was sufficient to identify arc family
120          * and release: 0x50 to 0x53 was HS38, 0x54 was HS48 (dual issue)
121          */
122
123         if (cpu->core.family < 0x54) { /* includes arc700 */
124
125                 for (tbl = &arc_legacy_rel[0]; tbl->id != 0; tbl++) {
126                         if (cpu->core.family == tbl->id) {
127                                 cpu->release = tbl->str;
128                                 break;
129                         }
130                 }
131
132                 if (is_isa_arcompact())
133                         cpu->name = "ARC700";
134                 else if (tbl->str)
135                         cpu->name = "HS38";
136                 else
137                         cpu->name = cpu->release = "Unknown";
138
139                 return;
140         }
141
142         /*
143          * However the subsequent HS release (same 0x54) allow HS38 or HS48
144          * configurations and encode this info in a different BCR.
145          * The BCR was introduced in 0x54 so can't be read unconditionally.
146          */
147
148         READ_BCR(ARC_REG_MICRO_ARCH_BCR, uarch);
149
150         if (uarch.prod == 4) {
151                 cpu->name = "HS48";
152                 cpu->extn.dual = 1;
153
154         } else {
155                 cpu->name = "HS38";
156         }
157
158         for (tbl = &arc_cpu_rel[0]; tbl->id != 0xFF; tbl++) {
159                 if (uarch.maj == tbl->id) {
160                         cpu->release = tbl->str;
161                         break;
162                 }
163         }
164 }
165
166 static void read_arc_build_cfg_regs(void)
167 {
168         struct bcr_timer timer;
169         struct bcr_generic bcr;
170         struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
171         struct bcr_isa_arcv2 isa;
172         struct bcr_actionpoint ap;
173
174         FIX_PTR(cpu);
175
176         READ_BCR(AUX_IDENTITY, cpu->core);
177         decode_arc_core(cpu);
178
179         READ_BCR(ARC_REG_TIMERS_BCR, timer);
180         cpu->extn.timer0 = timer.t0;
181         cpu->extn.timer1 = timer.t1;
182         cpu->extn.rtc = timer.rtc;
183
184         cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);
185
186         READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);
187
188         /* Read CCM BCRs for boot reporting even if not enabled in Kconfig */
189         read_decode_ccm_bcr(cpu);
190
191         read_decode_mmu_bcr();
192         read_decode_cache_bcr();
193
194         if (is_isa_arcompact()) {
195                 struct bcr_fp_arcompact sp, dp;
196                 struct bcr_bpu_arcompact bpu;
197
198                 READ_BCR(ARC_REG_FP_BCR, sp);
199                 READ_BCR(ARC_REG_DPFP_BCR, dp);
200                 cpu->extn.fpu_sp = sp.ver ? 1 : 0;
201                 cpu->extn.fpu_dp = dp.ver ? 1 : 0;
202
203                 READ_BCR(ARC_REG_BPU_BCR, bpu);
204                 cpu->bpu.ver = bpu.ver;
205                 cpu->bpu.full = bpu.fam ? 1 : 0;
206                 if (bpu.ent) {
207                         cpu->bpu.num_cache = 256 << (bpu.ent - 1);
208                         cpu->bpu.num_pred = 256 << (bpu.ent - 1);
209                 }
210         } else {
211                 struct bcr_fp_arcv2 spdp;
212                 struct bcr_bpu_arcv2 bpu;
213
214                 READ_BCR(ARC_REG_FP_V2_BCR, spdp);
215                 cpu->extn.fpu_sp = spdp.sp ? 1 : 0;
216                 cpu->extn.fpu_dp = spdp.dp ? 1 : 0;
217
218                 READ_BCR(ARC_REG_BPU_BCR, bpu);
219                 cpu->bpu.ver = bpu.ver;
220                 cpu->bpu.full = bpu.ft;
221                 cpu->bpu.num_cache = 256 << bpu.bce;
222                 cpu->bpu.num_pred = 2048 << bpu.pte;
223                 cpu->bpu.ret_stk = 4 << bpu.rse;
224
225                 /* if dual issue hardware, is it enabled ? */
226                 if (cpu->extn.dual) {
227                         unsigned int exec_ctrl;
228
229                         READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
230                         cpu->extn.dual_enb = !(exec_ctrl & 1);
231                 }
232         }
233
234         READ_BCR(ARC_REG_AP_BCR, ap);
235         if (ap.ver) {
236                 cpu->extn.ap_num = 2 << ap.num;
237                 cpu->extn.ap_full = !ap.min;
238         }
239
240         READ_BCR(ARC_REG_SMART_BCR, bcr);
241         cpu->extn.smart = bcr.ver ? 1 : 0;
242
243         READ_BCR(ARC_REG_RTT_BCR, bcr);
244         cpu->extn.rtt = bcr.ver ? 1 : 0;
245
246         READ_BCR(ARC_REG_ISA_CFG_BCR, isa);
247
248         /* some hacks for lack of feature BCR info in old ARC700 cores */
249         if (is_isa_arcompact()) {
250                 if (!isa.ver)   /* ISA BCR absent, use Kconfig info */
251                         cpu->isa.atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
252                 else {
253                         /* ARC700_BUILD only has 2 bits of isa info */
254                         struct bcr_generic bcr = *(struct bcr_generic *)&isa;
255                         cpu->isa.atomic = bcr.info & 1;
256                 }
257
258                 cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
259
260                  /* there's no direct way to distinguish 750 vs. 770 */
261                 if (unlikely(cpu->core.family < 0x34 || cpu->mmu.ver < 3))
262                         cpu->name = "ARC750";
263         } else {
264                 cpu->isa = isa;
265         }
266 }
267
268 static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
269 {
270         struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
271         struct bcr_identity *core = &cpu->core;
272         char mpy_opt[16];
273         int n = 0;
274
275         FIX_PTR(cpu);
276
277         n += scnprintf(buf + n, len - n,
278                        "\nIDENTITY\t: ARCVER [%#02x] ARCNUM [%#02x] CHIPID [%#4x]\n",
279                        core->family, core->cpu_id, core->chip_id);
280
281         n += scnprintf(buf + n, len - n, "processor [%d]\t: %s %s (%s ISA) %s%s%s\n",
282                        cpu_id, cpu->name, cpu->release,
283                        is_isa_arcompact() ? "ARCompact" : "ARCv2",
284                        IS_AVAIL1(cpu->isa.be, "[Big-Endian]"),
285                        IS_AVAIL3(cpu->extn.dual, cpu->extn.dual_enb, " Dual-Issue "));
286
287         n += scnprintf(buf + n, len - n, "Timers\t\t: %s%s%s%s%s%s\nISA Extn\t: ",
288                        IS_AVAIL1(cpu->extn.timer0, "Timer0 "),
289                        IS_AVAIL1(cpu->extn.timer1, "Timer1 "),
290                        IS_AVAIL2(cpu->extn.rtc, "RTC [UP 64-bit] ", CONFIG_ARC_TIMERS_64BIT),
291                        IS_AVAIL2(cpu->extn.gfrc, "GFRC [SMP 64-bit] ", CONFIG_ARC_TIMERS_64BIT));
292
293         if (cpu->extn_mpy.ver) {
294                 if (is_isa_arcompact()) {
295                         scnprintf(mpy_opt, 16, "mpy");
296                 } else {
297
298                         int opt = 2;    /* stock MPY/MPYH */
299
300                         if (cpu->extn_mpy.dsp)  /* OPT 7-9 */
301                                 opt = cpu->extn_mpy.dsp + 6;
302
303                         scnprintf(mpy_opt, 16, "mpy[opt %d] ", opt);
304                 }
305         }
306
307         n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s%s%s\n",
308                        IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
309                        IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
310                        IS_AVAIL2(cpu->isa.unalign, "unalign ", CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS),
311                        IS_AVAIL1(cpu->extn_mpy.ver, mpy_opt),
312                        IS_AVAIL1(cpu->isa.div_rem, "div_rem "));
313
314         if (cpu->bpu.ver) {
315                 n += scnprintf(buf + n, len - n,
316                               "BPU\t\t: %s%s match, cache:%d, Predict Table:%d Return stk: %d",
317                               IS_AVAIL1(cpu->bpu.full, "full"),
318                               IS_AVAIL1(!cpu->bpu.full, "partial"),
319                               cpu->bpu.num_cache, cpu->bpu.num_pred, cpu->bpu.ret_stk);
320
321                 if (is_isa_arcv2()) {
322                         struct bcr_lpb lpb;
323
324                         READ_BCR(ARC_REG_LPB_BUILD, lpb);
325                         if (lpb.ver) {
326                                 unsigned int ctl;
327                                 ctl = read_aux_reg(ARC_REG_LPB_CTRL);
328
329                                 n += scnprintf(buf + n, len - n, " Loop Buffer:%d %s",
330                                                lpb.entries,
331                                                IS_DISABLED_RUN(!ctl));
332                         }
333                 }
334                 n += scnprintf(buf + n, len - n, "\n");
335         }
336
337         return buf;
338 }
339
340 static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
341 {
342         int n = 0;
343         struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
344
345         FIX_PTR(cpu);
346
347         n += scnprintf(buf + n, len - n, "Vector Table\t: %#x\n", cpu->vec_base);
348
349         if (cpu->extn.fpu_sp || cpu->extn.fpu_dp)
350                 n += scnprintf(buf + n, len - n, "FPU\t\t: %s%s\n",
351                                IS_AVAIL1(cpu->extn.fpu_sp, "SP "),
352                                IS_AVAIL1(cpu->extn.fpu_dp, "DP "));
353
354         if (cpu->extn.ap_num | cpu->extn.smart | cpu->extn.rtt) {
355                 n += scnprintf(buf + n, len - n, "DEBUG\t\t: %s%s",
356                                IS_AVAIL1(cpu->extn.smart, "smaRT "),
357                                IS_AVAIL1(cpu->extn.rtt, "RTT "));
358                 if (cpu->extn.ap_num) {
359                         n += scnprintf(buf + n, len - n, "ActionPoint %d/%s",
360                                        cpu->extn.ap_num,
361                                        cpu->extn.ap_full ? "full":"min");
362                 }
363                 n += scnprintf(buf + n, len - n, "\n");
364         }
365
366         if (cpu->dccm.sz || cpu->iccm.sz)
367                 n += scnprintf(buf + n, len - n, "Extn [CCM]\t: DCCM @ %x, %d KB / ICCM: @ %x, %d KB\n",
368                                cpu->dccm.base_addr, TO_KB(cpu->dccm.sz),
369                                cpu->iccm.base_addr, TO_KB(cpu->iccm.sz));
370
371         if (is_isa_arcv2()) {
372
373                 /* Error Protection: ECC/Parity */
374                 struct bcr_erp erp;
375                 READ_BCR(ARC_REG_ERP_BUILD, erp);
376
377                 if (erp.ver) {
378                         struct  ctl_erp ctl;
379                         READ_BCR(ARC_REG_ERP_CTRL, ctl);
380
381                         /* inverted bits: 0 means enabled */
382                         n += scnprintf(buf + n, len - n, "Extn [ECC]\t: %s%s%s%s%s%s\n",
383                                 IS_AVAIL3(erp.ic,  !ctl.dpi, "IC "),
384                                 IS_AVAIL3(erp.dc,  !ctl.dpd, "DC "),
385                                 IS_AVAIL3(erp.mmu, !ctl.mpd, "MMU "));
386                 }
387         }
388
389         return buf;
390 }
391
392 static void arc_chk_core_config(void)
393 {
394         struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
395         int saved = 0, present = 0;
396         char *opt_nm = NULL;
397
398         if (!cpu->extn.timer0)
399                 panic("Timer0 is not present!\n");
400
401         if (!cpu->extn.timer1)
402                 panic("Timer1 is not present!\n");
403
404 #ifdef CONFIG_ARC_HAS_DCCM
405         /*
406          * DCCM can be arbit placed in hardware.
407          * Make sure it's placement/sz matches what Linux is built with
408          */
409         if ((unsigned int)__arc_dccm_base != cpu->dccm.base_addr)
410                 panic("Linux built with incorrect DCCM Base address\n");
411
412         if (CONFIG_ARC_DCCM_SZ != cpu->dccm.sz)
413                 panic("Linux built with incorrect DCCM Size\n");
414 #endif
415
416 #ifdef CONFIG_ARC_HAS_ICCM
417         if (CONFIG_ARC_ICCM_SZ != cpu->iccm.sz)
418                 panic("Linux built with incorrect ICCM Size\n");
419 #endif
420
421         /*
422          * FP hardware/software config sanity
423          * -If hardware present, kernel needs to save/restore FPU state
424          * -If not, it will crash trying to save/restore the non-existant regs
425          */
426
427         if (is_isa_arcompact()) {
428                 opt_nm = "CONFIG_ARC_FPU_SAVE_RESTORE";
429                 saved = IS_ENABLED(CONFIG_ARC_FPU_SAVE_RESTORE);
430
431                 /* only DPDP checked since SP has no arch visible regs */
432                 present = cpu->extn.fpu_dp;
433         } else {
434                 opt_nm = "CONFIG_ARC_HAS_ACCL_REGS";
435                 saved = IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS);
436
437                 /* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */
438                 present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp;
439         }
440
441         if (present && !saved)
442                 pr_warn("Enable %s for working apps\n", opt_nm);
443         else if (!present && saved)
444                 panic("Disable %s, hardware NOT present\n", opt_nm);
445 }
446
447 /*
448  * Initialize and setup the processor core
449  * This is called by all the CPUs thus should not do special case stuff
450  *    such as only for boot CPU etc
451  */
452
453 void setup_processor(void)
454 {
455         char str[512];
456         int cpu_id = smp_processor_id();
457
458         read_arc_build_cfg_regs();
459         arc_init_IRQ();
460
461         pr_info("%s", arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));
462
463         arc_mmu_init();
464         arc_cache_init();
465
466         pr_info("%s", arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));
467         pr_info("%s", arc_platform_smp_cpuinfo());
468
469         arc_chk_core_config();
470 }
471
472 static inline bool uboot_arg_invalid(unsigned long addr)
473 {
474         /*
475          * Check that it is a untranslated address (although MMU is not enabled
476          * yet, it being a high address ensures this is not by fluke)
477          */
478         if (addr < PAGE_OFFSET)
479                 return true;
480
481         /* Check that address doesn't clobber resident kernel image */
482         return addr >= (unsigned long)_stext && addr <= (unsigned long)_end;
483 }
484
485 #define IGNORE_ARGS             "Ignore U-boot args: "
486
487 /* uboot_tag values for U-boot - kernel ABI revision 0; see head.S */
488 #define UBOOT_TAG_NONE          0
489 #define UBOOT_TAG_CMDLINE       1
490 #define UBOOT_TAG_DTB           2
491 /* We always pass 0 as magic from U-boot */
492 #define UBOOT_MAGIC_VALUE       0
493
494 void __init handle_uboot_args(void)
495 {
496         bool use_embedded_dtb = true;
497         bool append_cmdline = false;
498
499         /* check that we know this tag */
500         if (uboot_tag != UBOOT_TAG_NONE &&
501             uboot_tag != UBOOT_TAG_CMDLINE &&
502             uboot_tag != UBOOT_TAG_DTB) {
503                 pr_warn(IGNORE_ARGS "invalid uboot tag: '%08x'\n", uboot_tag);
504                 goto ignore_uboot_args;
505         }
506
507         if (uboot_magic != UBOOT_MAGIC_VALUE) {
508                 pr_warn(IGNORE_ARGS "non zero uboot magic\n");
509                 goto ignore_uboot_args;
510         }
511
512         if (uboot_tag != UBOOT_TAG_NONE &&
513             uboot_arg_invalid((unsigned long)uboot_arg)) {
514                 pr_warn(IGNORE_ARGS "invalid uboot arg: '%px'\n", uboot_arg);
515                 goto ignore_uboot_args;
516         }
517
518         /* see if U-boot passed an external Device Tree blob */
519         if (uboot_tag == UBOOT_TAG_DTB) {
520                 machine_desc = setup_machine_fdt((void *)uboot_arg);
521
522                 /* external Device Tree blob is invalid - use embedded one */
523                 use_embedded_dtb = !machine_desc;
524         }
525
526         if (uboot_tag == UBOOT_TAG_CMDLINE)
527                 append_cmdline = true;
528
529 ignore_uboot_args:
530
531         if (use_embedded_dtb) {
532                 machine_desc = setup_machine_fdt(__dtb_start);
533                 if (!machine_desc)
534                         panic("Embedded DT invalid\n");
535         }
536
537         /*
538          * NOTE: @boot_command_line is populated by setup_machine_fdt() so this
539          * append processing can only happen after.
540          */
541         if (append_cmdline) {
542                 /* Ensure a whitespace between the 2 cmdlines */
543                 strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
544                 strlcat(boot_command_line, uboot_arg, COMMAND_LINE_SIZE);
545         }
546 }
547
548 void __init setup_arch(char **cmdline_p)
549 {
550         handle_uboot_args();
551
552         /* Save unparsed command line copy for /proc/cmdline */
553         *cmdline_p = boot_command_line;
554
555         /* To force early parsing of things like mem=xxx */
556         parse_early_param();
557
558         /* Platform/board specific: e.g. early console registration */
559         if (machine_desc->init_early)
560                 machine_desc->init_early();
561
562         smp_init_cpus();
563
564         setup_processor();
565         setup_arch_memory();
566
567         /* copy flat DT out of .init and then unflatten it */
568         unflatten_and_copy_device_tree();
569
570         /* Can be issue if someone passes cmd line arg "ro"
571          * But that is unlikely so keeping it as it is
572          */
573         root_mountflags &= ~MS_RDONLY;
574
575         arc_unwind_init();
576 }
577
578 /*
579  * Called from start_kernel() - boot CPU only
580  */
581 void __init time_init(void)
582 {
583         of_clk_init(NULL);
584         timer_probe();
585 }
586
587 static int __init customize_machine(void)
588 {
589         if (machine_desc->init_machine)
590                 machine_desc->init_machine();
591
592         return 0;
593 }
594 arch_initcall(customize_machine);
595
596 static int __init init_late_machine(void)
597 {
598         if (machine_desc->init_late)
599                 machine_desc->init_late();
600
601         return 0;
602 }
603 late_initcall(init_late_machine);
604 /*
605  *  Get CPU information for use by the procfs.
606  */
607
608 #define cpu_to_ptr(c)   ((void *)(0xFFFF0000 | (unsigned int)(c)))
609 #define ptr_to_cpu(p)   (~0xFFFF0000UL & (unsigned int)(p))
610
611 static int show_cpuinfo(struct seq_file *m, void *v)
612 {
613         char *str;
614         int cpu_id = ptr_to_cpu(v);
615         struct device *cpu_dev = get_cpu_device(cpu_id);
616         struct clk *cpu_clk;
617         unsigned long freq = 0;
618
619         if (!cpu_online(cpu_id)) {
620                 seq_printf(m, "processor [%d]\t: Offline\n", cpu_id);
621                 goto done;
622         }
623
624         str = (char *)__get_free_page(GFP_KERNEL);
625         if (!str)
626                 goto done;
627
628         seq_printf(m, arc_cpu_mumbojumbo(cpu_id, str, PAGE_SIZE));
629
630         cpu_clk = clk_get(cpu_dev, NULL);
631         if (IS_ERR(cpu_clk)) {
632                 seq_printf(m, "CPU speed \t: Cannot get clock for processor [%d]\n",
633                            cpu_id);
634         } else {
635                 freq = clk_get_rate(cpu_clk);
636         }
637         if (freq)
638                 seq_printf(m, "CPU speed\t: %lu.%02lu Mhz\n",
639                            freq / 1000000, (freq / 10000) % 100);
640
641         seq_printf(m, "Bogo MIPS\t: %lu.%02lu\n",
642                    loops_per_jiffy / (500000 / HZ),
643                    (loops_per_jiffy / (5000 / HZ)) % 100);
644
645         seq_printf(m, arc_mmu_mumbojumbo(cpu_id, str, PAGE_SIZE));
646         seq_printf(m, arc_cache_mumbojumbo(cpu_id, str, PAGE_SIZE));
647         seq_printf(m, arc_extn_mumbojumbo(cpu_id, str, PAGE_SIZE));
648         seq_printf(m, arc_platform_smp_cpuinfo());
649
650         free_page((unsigned long)str);
651 done:
652         seq_printf(m, "\n");
653
654         return 0;
655 }
656
657 static void *c_start(struct seq_file *m, loff_t *pos)
658 {
659         /*
660          * Callback returns cpu-id to iterator for show routine, NULL to stop.
661          * However since NULL is also a valid cpu-id (0), we use a round-about
662          * way to pass it w/o having to kmalloc/free a 2 byte string.
663          * Encode cpu-id as 0xFFcccc, which is decoded by show routine.
664          */
665         return *pos < nr_cpu_ids ? cpu_to_ptr(*pos) : NULL;
666 }
667
668 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
669 {
670         ++*pos;
671         return c_start(m, pos);
672 }
673
674 static void c_stop(struct seq_file *m, void *v)
675 {
676 }
677
678 const struct seq_operations cpuinfo_op = {
679         .start  = c_start,
680         .next   = c_next,
681         .stop   = c_stop,
682         .show   = show_cpuinfo
683 };
684
685 static DEFINE_PER_CPU(struct cpu, cpu_topology);
686
687 static int __init topology_init(void)
688 {
689         int cpu;
690
691         for_each_present_cpu(cpu)
692             register_cpu(&per_cpu(cpu_topology, cpu), cpu);
693
694         return 0;
695 }
696
697 subsys_initcall(topology_init);