xref: /linux/arch/arc/kernel/setup.c (revision 662fa3d6099374c4615bf64d06895e3573b935b2) 
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/clocksource.h>
12 #include <linux/console.h>
13 #include <linux/module.h>
14 #include <linux/sizes.h>
15 #include <linux/cpu.h>
16 #include <linux/of_clk.h>
17 #include <linux/of_fdt.h>
18 #include <linux/of.h>
19 #include <linux/cache.h>
20 #include <uapi/linux/mount.h>
21 #include <asm/sections.h>
22 #include <asm/arcregs.h>
23 #include <asm/asserts.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 #include <asm/dsp-impl.h>
32 
33 #define FIX_PTR(x)  __asm__ __volatile__(";" : "+r"(x))
34 
35 unsigned int intr_to_DE_cnt;
36 
37 /* Part of U-boot ABI: see head.S */
38 int __initdata uboot_tag;
39 int __initdata uboot_magic;
40 char __initdata *uboot_arg;
41 
42 const struct machine_desc *machine_desc;
43 
44 struct task_struct *_current_task[NR_CPUS];	/* For stack switching */
45 
46 struct cpuinfo_arc cpuinfo_arc700[NR_CPUS];
47 
48 static const struct id_to_str arc_legacy_rel[] = {
49 	/* ID.ARCVER,	Release */
50 #ifdef CONFIG_ISA_ARCOMPACT
51 	{ 0x34, 	"R4.10"},
52 	{ 0x35, 	"R4.11"},
53 #else
54 	{ 0x51, 	"R2.0" },
55 	{ 0x52, 	"R2.1" },
56 	{ 0x53,		"R3.0" },
57 #endif
58 	{ 0x00,		NULL   }
59 };
60 
61 static const struct id_to_str arc_hs_ver54_rel[] = {
62 	/* UARCH.MAJOR,	Release */
63 	{  0,		"R3.10a"},
64 	{  1,		"R3.50a"},
65 	{  2,		"R3.60a"},
66 	{  3,		"R4.00a"},
67 	{  0xFF,	NULL   }
68 };
69 
70 static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
71 {
72 	if (is_isa_arcompact()) {
73 		struct bcr_iccm_arcompact iccm;
74 		struct bcr_dccm_arcompact dccm;
75 
76 		READ_BCR(ARC_REG_ICCM_BUILD, iccm);
77 		if (iccm.ver) {
78 			cpu->iccm.sz = 4096 << iccm.sz;	/* 8K to 512K */
79 			cpu->iccm.base_addr = iccm.base << 16;
80 		}
81 
82 		READ_BCR(ARC_REG_DCCM_BUILD, dccm);
83 		if (dccm.ver) {
84 			unsigned long base;
85 			cpu->dccm.sz = 2048 << dccm.sz;	/* 2K to 256K */
86 
87 			base = read_aux_reg(ARC_REG_DCCM_BASE_BUILD);
88 			cpu->dccm.base_addr = base & ~0xF;
89 		}
90 	} else {
91 		struct bcr_iccm_arcv2 iccm;
92 		struct bcr_dccm_arcv2 dccm;
93 		unsigned long region;
94 
95 		READ_BCR(ARC_REG_ICCM_BUILD, iccm);
96 		if (iccm.ver) {
97 			cpu->iccm.sz = 256 << iccm.sz00;	/* 512B to 16M */
98 			if (iccm.sz00 == 0xF && iccm.sz01 > 0)
99 				cpu->iccm.sz <<= iccm.sz01;
100 
101 			region = read_aux_reg(ARC_REG_AUX_ICCM);
102 			cpu->iccm.base_addr = region & 0xF0000000;
103 		}
104 
105 		READ_BCR(ARC_REG_DCCM_BUILD, dccm);
106 		if (dccm.ver) {
107 			cpu->dccm.sz = 256 << dccm.sz0;
108 			if (dccm.sz0 == 0xF && dccm.sz1 > 0)
109 				cpu->dccm.sz <<= dccm.sz1;
110 
111 			region = read_aux_reg(ARC_REG_AUX_DCCM);
112 			cpu->dccm.base_addr = region & 0xF0000000;
113 		}
114 	}
115 }
116 
117 static void decode_arc_core(struct cpuinfo_arc *cpu)
118 {
119 	struct bcr_uarch_build_arcv2 uarch;
120 	const struct id_to_str *tbl;
121 
122 	if (cpu->core.family < 0x54) { /* includes arc700 */
123 
124 		for (tbl = &arc_legacy_rel[0]; tbl->id != 0; tbl++) {
125 			if (cpu->core.family == tbl->id) {
126 				cpu->release = tbl->str;
127 				break;
128 			}
129 		}
130 
131 		if (is_isa_arcompact())
132 			cpu->name = "ARC700";
133 		else if (tbl->str)
134 			cpu->name = "HS38";
135 		else
136 			cpu->name = cpu->release = "Unknown";
137 
138 		return;
139 	}
140 
141 	/*
142 	 * Initial HS cores bumped AUX IDENTITY.ARCVER for each release until
143 	 * ARCVER 0x54 which introduced AUX MICRO_ARCH_BUILD and subsequent
144 	 * releases only update it.
145 	 */
146 	READ_BCR(ARC_REG_MICRO_ARCH_BCR, uarch);
147 
148 	if (uarch.prod == 4) {
149 		cpu->name = "HS48";
150 		cpu->extn.dual = 1;
151 
152 	} else {
153 		cpu->name = "HS38";
154 	}
155 
156 	for (tbl = &arc_hs_ver54_rel[0]; tbl->id != 0xFF; tbl++) {
157 		if (uarch.maj == tbl->id) {
158 			cpu->release = tbl->str;
159 			break;
160 		}
161 	}
162 }
163 
164 static void read_arc_build_cfg_regs(void)
165 {
166 	struct bcr_timer timer;
167 	struct bcr_generic bcr;
168 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
169 	struct bcr_isa_arcv2 isa;
170 	struct bcr_actionpoint ap;
171 
172 	FIX_PTR(cpu);
173 
174 	READ_BCR(AUX_IDENTITY, cpu->core);
175 	decode_arc_core(cpu);
176 
177 	READ_BCR(ARC_REG_TIMERS_BCR, timer);
178 	cpu->extn.timer0 = timer.t0;
179 	cpu->extn.timer1 = timer.t1;
180 	cpu->extn.rtc = timer.rtc;
181 
182 	cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);
183 
184 	READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);
185 
186 	/* Read CCM BCRs for boot reporting even if not enabled in Kconfig */
187 	read_decode_ccm_bcr(cpu);
188 
189 	read_decode_mmu_bcr();
190 	read_decode_cache_bcr();
191 
192 	if (is_isa_arcompact()) {
193 		struct bcr_fp_arcompact sp, dp;
194 		struct bcr_bpu_arcompact bpu;
195 
196 		READ_BCR(ARC_REG_FP_BCR, sp);
197 		READ_BCR(ARC_REG_DPFP_BCR, dp);
198 		cpu->extn.fpu_sp = sp.ver ? 1 : 0;
199 		cpu->extn.fpu_dp = dp.ver ? 1 : 0;
200 
201 		READ_BCR(ARC_REG_BPU_BCR, bpu);
202 		cpu->bpu.ver = bpu.ver;
203 		cpu->bpu.full = bpu.fam ? 1 : 0;
204 		if (bpu.ent) {
205 			cpu->bpu.num_cache = 256 << (bpu.ent - 1);
206 			cpu->bpu.num_pred = 256 << (bpu.ent - 1);
207 		}
208 	} else {
209 		struct bcr_fp_arcv2 spdp;
210 		struct bcr_bpu_arcv2 bpu;
211 
212 		READ_BCR(ARC_REG_FP_V2_BCR, spdp);
213 		cpu->extn.fpu_sp = spdp.sp ? 1 : 0;
214 		cpu->extn.fpu_dp = spdp.dp ? 1 : 0;
215 
216 		READ_BCR(ARC_REG_BPU_BCR, bpu);
217 		cpu->bpu.ver = bpu.ver;
218 		cpu->bpu.full = bpu.ft;
219 		cpu->bpu.num_cache = 256 << bpu.bce;
220 		cpu->bpu.num_pred = 2048 << bpu.pte;
221 		cpu->bpu.ret_stk = 4 << bpu.rse;
222 
223 		/* if dual issue hardware, is it enabled ? */
224 		if (cpu->extn.dual) {
225 			unsigned int exec_ctrl;
226 
227 			READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
228 			cpu->extn.dual_enb = !(exec_ctrl & 1);
229 		}
230 	}
231 
232 	READ_BCR(ARC_REG_AP_BCR, ap);
233 	if (ap.ver) {
234 		cpu->extn.ap_num = 2 << ap.num;
235 		cpu->extn.ap_full = !ap.min;
236 	}
237 
238 	READ_BCR(ARC_REG_SMART_BCR, bcr);
239 	cpu->extn.smart = bcr.ver ? 1 : 0;
240 
241 	READ_BCR(ARC_REG_RTT_BCR, bcr);
242 	cpu->extn.rtt = bcr.ver ? 1 : 0;
243 
244 	READ_BCR(ARC_REG_ISA_CFG_BCR, isa);
245 
246 	/* some hacks for lack of feature BCR info in old ARC700 cores */
247 	if (is_isa_arcompact()) {
248 		if (!isa.ver)	/* ISA BCR absent, use Kconfig info */
249 			cpu->isa.atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
250 		else {
251 			/* ARC700_BUILD only has 2 bits of isa info */
252 			struct bcr_generic bcr = *(struct bcr_generic *)&isa;
253 			cpu->isa.atomic = bcr.info & 1;
254 		}
255 
256 		cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
257 
258 		 /* there's no direct way to distinguish 750 vs. 770 */
259 		if (unlikely(cpu->core.family < 0x34 || cpu->mmu.ver < 3))
260 			cpu->name = "ARC750";
261 	} else {
262 		cpu->isa = isa;
263 	}
264 }
265 
266 static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
267 {
268 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
269 	struct bcr_identity *core = &cpu->core;
270 	char mpy_opt[16];
271 	int n = 0;
272 
273 	FIX_PTR(cpu);
274 
275 	n += scnprintf(buf + n, len - n,
276 		       "\nIDENTITY\t: ARCVER [%#02x] ARCNUM [%#02x] CHIPID [%#4x]\n",
277 		       core->family, core->cpu_id, core->chip_id);
278 
279 	n += scnprintf(buf + n, len - n, "processor [%d]\t: %s %s (%s ISA) %s%s%s\n",
280 		       cpu_id, cpu->name, cpu->release,
281 		       is_isa_arcompact() ? "ARCompact" : "ARCv2",
282 		       IS_AVAIL1(cpu->isa.be, "[Big-Endian]"),
283 		       IS_AVAIL3(cpu->extn.dual, cpu->extn.dual_enb, " Dual-Issue "));
284 
285 	n += scnprintf(buf + n, len - n, "Timers\t\t: %s%s%s%s%s%s\nISA Extn\t: ",
286 		       IS_AVAIL1(cpu->extn.timer0, "Timer0 "),
287 		       IS_AVAIL1(cpu->extn.timer1, "Timer1 "),
288 		       IS_AVAIL2(cpu->extn.rtc, "RTC [UP 64-bit] ", CONFIG_ARC_TIMERS_64BIT),
289 		       IS_AVAIL2(cpu->extn.gfrc, "GFRC [SMP 64-bit] ", CONFIG_ARC_TIMERS_64BIT));
290 
291 	if (cpu->extn_mpy.ver) {
292 		if (is_isa_arcompact()) {
293 			scnprintf(mpy_opt, 16, "mpy");
294 		} else {
295 
296 			int opt = 2;	/* stock MPY/MPYH */
297 
298 			if (cpu->extn_mpy.dsp)	/* OPT 7-9 */
299 				opt = cpu->extn_mpy.dsp + 6;
300 
301 			scnprintf(mpy_opt, 16, "mpy[opt %d] ", opt);
302 		}
303 	}
304 
305 	n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s%s%s\n",
306 		       IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
307 		       IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
308 		       IS_AVAIL2(cpu->isa.unalign, "unalign ", CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS),
309 		       IS_AVAIL1(cpu->extn_mpy.ver, mpy_opt),
310 		       IS_AVAIL1(cpu->isa.div_rem, "div_rem "));
311 
312 	if (cpu->bpu.ver) {
313 		n += scnprintf(buf + n, len - n,
314 			      "BPU\t\t: %s%s match, cache:%d, Predict Table:%d Return stk: %d",
315 			      IS_AVAIL1(cpu->bpu.full, "full"),
316 			      IS_AVAIL1(!cpu->bpu.full, "partial"),
317 			      cpu->bpu.num_cache, cpu->bpu.num_pred, cpu->bpu.ret_stk);
318 
319 		if (is_isa_arcv2()) {
320 			struct bcr_lpb lpb;
321 
322 			READ_BCR(ARC_REG_LPB_BUILD, lpb);
323 			if (lpb.ver) {
324 				unsigned int ctl;
325 				ctl = read_aux_reg(ARC_REG_LPB_CTRL);
326 
327 				n += scnprintf(buf + n, len - n, " Loop Buffer:%d %s",
328 					       lpb.entries,
329 					       IS_DISABLED_RUN(!ctl));
330 			}
331 		}
332 		n += scnprintf(buf + n, len - n, "\n");
333 	}
334 
335 	return buf;
336 }
337 
338 static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
339 {
340 	int n = 0;
341 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
342 
343 	FIX_PTR(cpu);
344 
345 	n += scnprintf(buf + n, len - n, "Vector Table\t: %#x\n", cpu->vec_base);
346 
347 	if (cpu->extn.fpu_sp || cpu->extn.fpu_dp)
348 		n += scnprintf(buf + n, len - n, "FPU\t\t: %s%s\n",
349 			       IS_AVAIL1(cpu->extn.fpu_sp, "SP "),
350 			       IS_AVAIL1(cpu->extn.fpu_dp, "DP "));
351 
352 	if (cpu->extn.ap_num | cpu->extn.smart | cpu->extn.rtt) {
353 		n += scnprintf(buf + n, len - n, "DEBUG\t\t: %s%s",
354 			       IS_AVAIL1(cpu->extn.smart, "smaRT "),
355 			       IS_AVAIL1(cpu->extn.rtt, "RTT "));
356 		if (cpu->extn.ap_num) {
357 			n += scnprintf(buf + n, len - n, "ActionPoint %d/%s",
358 				       cpu->extn.ap_num,
359 				       cpu->extn.ap_full ? "full":"min");
360 		}
361 		n += scnprintf(buf + n, len - n, "\n");
362 	}
363 
364 	if (cpu->dccm.sz || cpu->iccm.sz)
365 		n += scnprintf(buf + n, len - n, "Extn [CCM]\t: DCCM @ %x, %d KB / ICCM: @ %x, %d KB\n",
366 			       cpu->dccm.base_addr, TO_KB(cpu->dccm.sz),
367 			       cpu->iccm.base_addr, TO_KB(cpu->iccm.sz));
368 
369 	if (is_isa_arcv2()) {
370 
371 		/* Error Protection: ECC/Parity */
372 		struct bcr_erp erp;
373 		READ_BCR(ARC_REG_ERP_BUILD, erp);
374 
375 		if (erp.ver) {
376 			struct  ctl_erp ctl;
377 			READ_BCR(ARC_REG_ERP_CTRL, ctl);
378 
379 			/* inverted bits: 0 means enabled */
380 			n += scnprintf(buf + n, len - n, "Extn [ECC]\t: %s%s%s%s%s%s\n",
381 				IS_AVAIL3(erp.ic,  !ctl.dpi, "IC "),
382 				IS_AVAIL3(erp.dc,  !ctl.dpd, "DC "),
383 				IS_AVAIL3(erp.mmu, !ctl.mpd, "MMU "));
384 		}
385 	}
386 
387 	return buf;
388 }
389 
390 void chk_opt_strict(char *opt_name, bool hw_exists, bool opt_ena)
391 {
392 	if (hw_exists && !opt_ena)
393 		pr_warn(" ! Enable %s for working apps\n", opt_name);
394 	else if (!hw_exists && opt_ena)
395 		panic("Disable %s, hardware NOT present\n", opt_name);
396 }
397 
398 void chk_opt_weak(char *opt_name, bool hw_exists, bool opt_ena)
399 {
400 	if (!hw_exists && opt_ena)
401 		panic("Disable %s, hardware NOT present\n", opt_name);
402 }
403 
404 static void arc_chk_core_config(void)
405 {
406 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
407 	int present = 0;
408 
409 	if (!cpu->extn.timer0)
410 		panic("Timer0 is not present!\n");
411 
412 	if (!cpu->extn.timer1)
413 		panic("Timer1 is not present!\n");
414 
415 #ifdef CONFIG_ARC_HAS_DCCM
416 	/*
417 	 * DCCM can be arbit placed in hardware.
418 	 * Make sure it's placement/sz matches what Linux is built with
419 	 */
420 	if ((unsigned int)__arc_dccm_base != cpu->dccm.base_addr)
421 		panic("Linux built with incorrect DCCM Base address\n");
422 
423 	if (CONFIG_ARC_DCCM_SZ * SZ_1K != cpu->dccm.sz)
424 		panic("Linux built with incorrect DCCM Size\n");
425 #endif
426 
427 #ifdef CONFIG_ARC_HAS_ICCM
428 	if (CONFIG_ARC_ICCM_SZ * SZ_1K != cpu->iccm.sz)
429 		panic("Linux built with incorrect ICCM Size\n");
430 #endif
431 
432 	/*
433 	 * FP hardware/software config sanity
434 	 * -If hardware present, kernel needs to save/restore FPU state
435 	 * -If not, it will crash trying to save/restore the non-existant regs
436 	 */
437 
438 	if (is_isa_arcompact()) {
439 		/* only DPDP checked since SP has no arch visible regs */
440 		present = cpu->extn.fpu_dp;
441 		CHK_OPT_STRICT(CONFIG_ARC_FPU_SAVE_RESTORE, present);
442 	} else {
443 		/* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */
444 		present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp;
445 		CHK_OPT_STRICT(CONFIG_ARC_HAS_ACCL_REGS, present);
446 
447 		dsp_config_check();
448 	}
449 }
450 
451 /*
452  * Initialize and setup the processor core
453  * This is called by all the CPUs thus should not do special case stuff
454  *    such as only for boot CPU etc
455  */
456 
457 void setup_processor(void)
458 {
459 	char str[512];
460 	int cpu_id = smp_processor_id();
461 
462 	read_arc_build_cfg_regs();
463 	arc_init_IRQ();
464 
465 	pr_info("%s", arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));
466 
467 	arc_mmu_init();
468 	arc_cache_init();
469 
470 	pr_info("%s", arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));
471 	pr_info("%s", arc_platform_smp_cpuinfo());
472 
473 	arc_chk_core_config();
474 }
475 
476 static inline bool uboot_arg_invalid(unsigned long addr)
477 {
478 	/*
479 	 * Check that it is a untranslated address (although MMU is not enabled
480 	 * yet, it being a high address ensures this is not by fluke)
481 	 */
482 	if (addr < PAGE_OFFSET)
483 		return true;
484 
485 	/* Check that address doesn't clobber resident kernel image */
486 	return addr >= (unsigned long)_stext && addr <= (unsigned long)_end;
487 }
488 
489 #define IGNORE_ARGS		"Ignore U-boot args: "
490 
491 /* uboot_tag values for U-boot - kernel ABI revision 0; see head.S */
492 #define UBOOT_TAG_NONE		0
493 #define UBOOT_TAG_CMDLINE	1
494 #define UBOOT_TAG_DTB		2
495 /* We always pass 0 as magic from U-boot */
496 #define UBOOT_MAGIC_VALUE	0
497 
498 void __init handle_uboot_args(void)
499 {
500 	bool use_embedded_dtb = true;
501 	bool append_cmdline = false;
502 
503 	/* check that we know this tag */
504 	if (uboot_tag != UBOOT_TAG_NONE &&
505 	    uboot_tag != UBOOT_TAG_CMDLINE &&
506 	    uboot_tag != UBOOT_TAG_DTB) {
507 		pr_warn(IGNORE_ARGS "invalid uboot tag: '%08x'\n", uboot_tag);
508 		goto ignore_uboot_args;
509 	}
510 
511 	if (uboot_magic != UBOOT_MAGIC_VALUE) {
512 		pr_warn(IGNORE_ARGS "non zero uboot magic\n");
513 		goto ignore_uboot_args;
514 	}
515 
516 	if (uboot_tag != UBOOT_TAG_NONE &&
517             uboot_arg_invalid((unsigned long)uboot_arg)) {
518 		pr_warn(IGNORE_ARGS "invalid uboot arg: '%px'\n", uboot_arg);
519 		goto ignore_uboot_args;
520 	}
521 
522 	/* see if U-boot passed an external Device Tree blob */
523 	if (uboot_tag == UBOOT_TAG_DTB) {
524 		machine_desc = setup_machine_fdt((void *)uboot_arg);
525 
526 		/* external Device Tree blob is invalid - use embedded one */
527 		use_embedded_dtb = !machine_desc;
528 	}
529 
530 	if (uboot_tag == UBOOT_TAG_CMDLINE)
531 		append_cmdline = true;
532 
533 ignore_uboot_args:
534 
535 	if (use_embedded_dtb) {
536 		machine_desc = setup_machine_fdt(__dtb_start);
537 		if (!machine_desc)
538 			panic("Embedded DT invalid\n");
539 	}
540 
541 	/*
542 	 * NOTE: @boot_command_line is populated by setup_machine_fdt() so this
543 	 * append processing can only happen after.
544 	 */
545 	if (append_cmdline) {
546 		/* Ensure a whitespace between the 2 cmdlines */
547 		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
548 		strlcat(boot_command_line, uboot_arg, COMMAND_LINE_SIZE);
549 	}
550 }
551 
552 void __init setup_arch(char **cmdline_p)
553 {
554 	handle_uboot_args();
555 
556 	/* Save unparsed command line copy for /proc/cmdline */
557 	*cmdline_p = boot_command_line;
558 
559 	/* To force early parsing of things like mem=xxx */
560 	parse_early_param();
561 
562 	/* Platform/board specific: e.g. early console registration */
563 	if (machine_desc->init_early)
564 		machine_desc->init_early();
565 
566 	smp_init_cpus();
567 
568 	setup_processor();
569 	setup_arch_memory();
570 
571 	/* copy flat DT out of .init and then unflatten it */
572 	unflatten_and_copy_device_tree();
573 
574 	/* Can be issue if someone passes cmd line arg "ro"
575 	 * But that is unlikely so keeping it as it is
576 	 */
577 	root_mountflags &= ~MS_RDONLY;
578 
579 	arc_unwind_init();
580 }
581 
582 /*
583  * Called from start_kernel() - boot CPU only
584  */
585 void __init time_init(void)
586 {
587 	of_clk_init(NULL);
588 	timer_probe();
589 }
590 
591 static int __init customize_machine(void)
592 {
593 	if (machine_desc->init_machine)
594 		machine_desc->init_machine();
595 
596 	return 0;
597 }
598 arch_initcall(customize_machine);
599 
600 static int __init init_late_machine(void)
601 {
602 	if (machine_desc->init_late)
603 		machine_desc->init_late();
604 
605 	return 0;
606 }
607 late_initcall(init_late_machine);
608 /*
609  *  Get CPU information for use by the procfs.
610  */
611 
612 #define cpu_to_ptr(c)	((void *)(0xFFFF0000 | (unsigned int)(c)))
613 #define ptr_to_cpu(p)	(~0xFFFF0000UL & (unsigned int)(p))
614 
615 static int show_cpuinfo(struct seq_file *m, void *v)
616 {
617 	char *str;
618 	int cpu_id = ptr_to_cpu(v);
619 	struct device *cpu_dev = get_cpu_device(cpu_id);
620 	struct clk *cpu_clk;
621 	unsigned long freq = 0;
622 
623 	if (!cpu_online(cpu_id)) {
624 		seq_printf(m, "processor [%d]\t: Offline\n", cpu_id);
625 		goto done;
626 	}
627 
628 	str = (char *)__get_free_page(GFP_KERNEL);
629 	if (!str)
630 		goto done;
631 
632 	seq_printf(m, arc_cpu_mumbojumbo(cpu_id, str, PAGE_SIZE));
633 
634 	cpu_clk = clk_get(cpu_dev, NULL);
635 	if (IS_ERR(cpu_clk)) {
636 		seq_printf(m, "CPU speed \t: Cannot get clock for processor [%d]\n",
637 			   cpu_id);
638 	} else {
639 		freq = clk_get_rate(cpu_clk);
640 	}
641 	if (freq)
642 		seq_printf(m, "CPU speed\t: %lu.%02lu Mhz\n",
643 			   freq / 1000000, (freq / 10000) % 100);
644 
645 	seq_printf(m, "Bogo MIPS\t: %lu.%02lu\n",
646 		   loops_per_jiffy / (500000 / HZ),
647 		   (loops_per_jiffy / (5000 / HZ)) % 100);
648 
649 	seq_printf(m, arc_mmu_mumbojumbo(cpu_id, str, PAGE_SIZE));
650 	seq_printf(m, arc_cache_mumbojumbo(cpu_id, str, PAGE_SIZE));
651 	seq_printf(m, arc_extn_mumbojumbo(cpu_id, str, PAGE_SIZE));
652 	seq_printf(m, arc_platform_smp_cpuinfo());
653 
654 	free_page((unsigned long)str);
655 done:
656 	seq_printf(m, "\n");
657 
658 	return 0;
659 }
660 
661 static void *c_start(struct seq_file *m, loff_t *pos)
662 {
663 	/*
664 	 * Callback returns cpu-id to iterator for show routine, NULL to stop.
665 	 * However since NULL is also a valid cpu-id (0), we use a round-about
666 	 * way to pass it w/o having to kmalloc/free a 2 byte string.
667 	 * Encode cpu-id as 0xFFcccc, which is decoded by show routine.
668 	 */
669 	return *pos < nr_cpu_ids ? cpu_to_ptr(*pos) : NULL;
670 }
671 
672 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
673 {
674 	++*pos;
675 	return c_start(m, pos);
676 }
677 
678 static void c_stop(struct seq_file *m, void *v)
679 {
680 }
681 
682 const struct seq_operations cpuinfo_op = {
683 	.start	= c_start,
684 	.next	= c_next,
685 	.stop	= c_stop,
686 	.show	= show_cpuinfo
687 };
688 
689 static DEFINE_PER_CPU(struct cpu, cpu_topology);
690 
691 static int __init topology_init(void)
692 {
693 	int cpu;
694 
695 	for_each_present_cpu(cpu)
696 	    register_cpu(&per_cpu(cpu_topology, cpu), cpu);
697 
698 	return 0;
699 }
700 
701 subsys_initcall(topology_init);
702