xref: /openbmc/linux/arch/arc/kernel/setup.c (revision 5b394b2d)
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 
34 unsigned int intr_to_DE_cnt;
35 
36 /* Part of U-boot ABI: see head.S */
37 int __initdata uboot_tag;
38 char __initdata *uboot_arg;
39 
40 const struct machine_desc *machine_desc;
41 
42 struct task_struct *_current_task[NR_CPUS];	/* For stack switching */
43 
44 struct cpuinfo_arc cpuinfo_arc700[NR_CPUS];
45 
46 static 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 
59 static 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 
71 static 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 
118 static 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 
242 static 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 
321 static 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 
372 static 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 
433 void 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 
452 static 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 
459 void __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  */
523 void __init time_init(void)
524 {
525 	of_clk_init(NULL);
526 	timer_probe();
527 }
528 
529 static int __init customize_machine(void)
530 {
531 	if (machine_desc->init_machine)
532 		machine_desc->init_machine();
533 
534 	return 0;
535 }
536 arch_initcall(customize_machine);
537 
538 static int __init init_late_machine(void)
539 {
540 	if (machine_desc->init_late)
541 		machine_desc->init_late();
542 
543 	return 0;
544 }
545 late_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 
553 static 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);
593 done:
594 	seq_printf(m, "\n");
595 
596 	return 0;
597 }
598 
599 static 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 
610 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
611 {
612 	++*pos;
613 	return c_start(m, pos);
614 }
615 
616 static void c_stop(struct seq_file *m, void *v)
617 {
618 }
619 
620 const struct seq_operations cpuinfo_op = {
621 	.start	= c_start,
622 	.next	= c_next,
623 	.stop	= c_stop,
624 	.show	= show_cpuinfo
625 };
626 
627 static DEFINE_PER_CPU(struct cpu, cpu_topology);
628 
629 static 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 
639 subsys_initcall(topology_init);
640