xref: /openbmc/linux/arch/arc/kernel/setup.c (revision 15e3ae36)
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/cpu.h>
15 #include <linux/of_clk.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/asserts.h>
23 #include <asm/tlb.h>
24 #include <asm/setup.h>
25 #include <asm/page.h>
26 #include <asm/irq.h>
27 #include <asm/unwind.h>
28 #include <asm/mach_desc.h>
29 #include <asm/smp.h>
30 #include <asm/dsp-impl.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 int __initdata uboot_magic;
39 char __initdata *uboot_arg;
40 
41 const struct machine_desc *machine_desc;
42 
43 struct task_struct *_current_task[NR_CPUS];	/* For stack switching */
44 
45 struct cpuinfo_arc cpuinfo_arc700[NR_CPUS];
46 
47 static const struct id_to_str arc_legacy_rel[] = {
48 	/* ID.ARCVER,	Release */
49 #ifdef CONFIG_ISA_ARCOMPACT
50 	{ 0x34, 	"R4.10"},
51 	{ 0x35, 	"R4.11"},
52 #else
53 	{ 0x51, 	"R2.0" },
54 	{ 0x52, 	"R2.1" },
55 	{ 0x53,		"R3.0" },
56 #endif
57 	{ 0x00,		NULL   }
58 };
59 
60 static const struct id_to_str arc_cpu_rel[] = {
61 	/* UARCH.MAJOR,	Release */
62 	{  0,		"R3.10a"},
63 	{  1,		"R3.50a"},
64 	{  0xFF,	NULL   }
65 };
66 
67 static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
68 {
69 	if (is_isa_arcompact()) {
70 		struct bcr_iccm_arcompact iccm;
71 		struct bcr_dccm_arcompact dccm;
72 
73 		READ_BCR(ARC_REG_ICCM_BUILD, iccm);
74 		if (iccm.ver) {
75 			cpu->iccm.sz = 4096 << iccm.sz;	/* 8K to 512K */
76 			cpu->iccm.base_addr = iccm.base << 16;
77 		}
78 
79 		READ_BCR(ARC_REG_DCCM_BUILD, dccm);
80 		if (dccm.ver) {
81 			unsigned long base;
82 			cpu->dccm.sz = 2048 << dccm.sz;	/* 2K to 256K */
83 
84 			base = read_aux_reg(ARC_REG_DCCM_BASE_BUILD);
85 			cpu->dccm.base_addr = base & ~0xF;
86 		}
87 	} else {
88 		struct bcr_iccm_arcv2 iccm;
89 		struct bcr_dccm_arcv2 dccm;
90 		unsigned long region;
91 
92 		READ_BCR(ARC_REG_ICCM_BUILD, iccm);
93 		if (iccm.ver) {
94 			cpu->iccm.sz = 256 << iccm.sz00;	/* 512B to 16M */
95 			if (iccm.sz00 == 0xF && iccm.sz01 > 0)
96 				cpu->iccm.sz <<= iccm.sz01;
97 
98 			region = read_aux_reg(ARC_REG_AUX_ICCM);
99 			cpu->iccm.base_addr = region & 0xF0000000;
100 		}
101 
102 		READ_BCR(ARC_REG_DCCM_BUILD, dccm);
103 		if (dccm.ver) {
104 			cpu->dccm.sz = 256 << dccm.sz0;
105 			if (dccm.sz0 == 0xF && dccm.sz1 > 0)
106 				cpu->dccm.sz <<= dccm.sz1;
107 
108 			region = read_aux_reg(ARC_REG_AUX_DCCM);
109 			cpu->dccm.base_addr = region & 0xF0000000;
110 		}
111 	}
112 }
113 
114 static void decode_arc_core(struct cpuinfo_arc *cpu)
115 {
116 	struct bcr_uarch_build_arcv2 uarch;
117 	const struct id_to_str *tbl;
118 
119 	/*
120 	 * Up until (including) the first core4 release (0x54) things were
121 	 * simple: AUX IDENTITY.ARCVER was sufficient to identify arc family
122 	 * and release: 0x50 to 0x53 was HS38, 0x54 was HS48 (dual issue)
123 	 */
124 
125 	if (cpu->core.family < 0x54) { /* includes arc700 */
126 
127 		for (tbl = &arc_legacy_rel[0]; tbl->id != 0; tbl++) {
128 			if (cpu->core.family == tbl->id) {
129 				cpu->release = tbl->str;
130 				break;
131 			}
132 		}
133 
134 		if (is_isa_arcompact())
135 			cpu->name = "ARC700";
136 		else if (tbl->str)
137 			cpu->name = "HS38";
138 		else
139 			cpu->name = cpu->release = "Unknown";
140 
141 		return;
142 	}
143 
144 	/*
145 	 * However the subsequent HS release (same 0x54) allow HS38 or HS48
146 	 * configurations and encode this info in a different BCR.
147 	 * The BCR was introduced in 0x54 so can't be read unconditionally.
148 	 */
149 
150 	READ_BCR(ARC_REG_MICRO_ARCH_BCR, uarch);
151 
152 	if (uarch.prod == 4) {
153 		cpu->name = "HS48";
154 		cpu->extn.dual = 1;
155 
156 	} else {
157 		cpu->name = "HS38";
158 	}
159 
160 	for (tbl = &arc_cpu_rel[0]; tbl->id != 0xFF; tbl++) {
161 		if (uarch.maj == tbl->id) {
162 			cpu->release = tbl->str;
163 			break;
164 		}
165 	}
166 }
167 
168 static void read_arc_build_cfg_regs(void)
169 {
170 	struct bcr_timer timer;
171 	struct bcr_generic bcr;
172 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
173 	struct bcr_isa_arcv2 isa;
174 	struct bcr_actionpoint ap;
175 
176 	FIX_PTR(cpu);
177 
178 	READ_BCR(AUX_IDENTITY, cpu->core);
179 	decode_arc_core(cpu);
180 
181 	READ_BCR(ARC_REG_TIMERS_BCR, timer);
182 	cpu->extn.timer0 = timer.t0;
183 	cpu->extn.timer1 = timer.t1;
184 	cpu->extn.rtc = timer.rtc;
185 
186 	cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);
187 
188 	READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);
189 
190 	/* Read CCM BCRs for boot reporting even if not enabled in Kconfig */
191 	read_decode_ccm_bcr(cpu);
192 
193 	read_decode_mmu_bcr();
194 	read_decode_cache_bcr();
195 
196 	if (is_isa_arcompact()) {
197 		struct bcr_fp_arcompact sp, dp;
198 		struct bcr_bpu_arcompact bpu;
199 
200 		READ_BCR(ARC_REG_FP_BCR, sp);
201 		READ_BCR(ARC_REG_DPFP_BCR, dp);
202 		cpu->extn.fpu_sp = sp.ver ? 1 : 0;
203 		cpu->extn.fpu_dp = dp.ver ? 1 : 0;
204 
205 		READ_BCR(ARC_REG_BPU_BCR, bpu);
206 		cpu->bpu.ver = bpu.ver;
207 		cpu->bpu.full = bpu.fam ? 1 : 0;
208 		if (bpu.ent) {
209 			cpu->bpu.num_cache = 256 << (bpu.ent - 1);
210 			cpu->bpu.num_pred = 256 << (bpu.ent - 1);
211 		}
212 	} else {
213 		struct bcr_fp_arcv2 spdp;
214 		struct bcr_bpu_arcv2 bpu;
215 
216 		READ_BCR(ARC_REG_FP_V2_BCR, spdp);
217 		cpu->extn.fpu_sp = spdp.sp ? 1 : 0;
218 		cpu->extn.fpu_dp = spdp.dp ? 1 : 0;
219 
220 		READ_BCR(ARC_REG_BPU_BCR, bpu);
221 		cpu->bpu.ver = bpu.ver;
222 		cpu->bpu.full = bpu.ft;
223 		cpu->bpu.num_cache = 256 << bpu.bce;
224 		cpu->bpu.num_pred = 2048 << bpu.pte;
225 		cpu->bpu.ret_stk = 4 << bpu.rse;
226 
227 		/* if dual issue hardware, is it enabled ? */
228 		if (cpu->extn.dual) {
229 			unsigned int exec_ctrl;
230 
231 			READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
232 			cpu->extn.dual_enb = !(exec_ctrl & 1);
233 		}
234 	}
235 
236 	READ_BCR(ARC_REG_AP_BCR, ap);
237 	if (ap.ver) {
238 		cpu->extn.ap_num = 2 << ap.num;
239 		cpu->extn.ap_full = !ap.min;
240 	}
241 
242 	READ_BCR(ARC_REG_SMART_BCR, bcr);
243 	cpu->extn.smart = bcr.ver ? 1 : 0;
244 
245 	READ_BCR(ARC_REG_RTT_BCR, bcr);
246 	cpu->extn.rtt = bcr.ver ? 1 : 0;
247 
248 	READ_BCR(ARC_REG_ISA_CFG_BCR, isa);
249 
250 	/* some hacks for lack of feature BCR info in old ARC700 cores */
251 	if (is_isa_arcompact()) {
252 		if (!isa.ver)	/* ISA BCR absent, use Kconfig info */
253 			cpu->isa.atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
254 		else {
255 			/* ARC700_BUILD only has 2 bits of isa info */
256 			struct bcr_generic bcr = *(struct bcr_generic *)&isa;
257 			cpu->isa.atomic = bcr.info & 1;
258 		}
259 
260 		cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
261 
262 		 /* there's no direct way to distinguish 750 vs. 770 */
263 		if (unlikely(cpu->core.family < 0x34 || cpu->mmu.ver < 3))
264 			cpu->name = "ARC750";
265 	} else {
266 		cpu->isa = isa;
267 	}
268 }
269 
270 static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
271 {
272 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
273 	struct bcr_identity *core = &cpu->core;
274 	char mpy_opt[16];
275 	int n = 0;
276 
277 	FIX_PTR(cpu);
278 
279 	n += scnprintf(buf + n, len - n,
280 		       "\nIDENTITY\t: ARCVER [%#02x] ARCNUM [%#02x] CHIPID [%#4x]\n",
281 		       core->family, core->cpu_id, core->chip_id);
282 
283 	n += scnprintf(buf + n, len - n, "processor [%d]\t: %s %s (%s ISA) %s%s%s\n",
284 		       cpu_id, cpu->name, cpu->release,
285 		       is_isa_arcompact() ? "ARCompact" : "ARCv2",
286 		       IS_AVAIL1(cpu->isa.be, "[Big-Endian]"),
287 		       IS_AVAIL3(cpu->extn.dual, cpu->extn.dual_enb, " Dual-Issue "));
288 
289 	n += scnprintf(buf + n, len - n, "Timers\t\t: %s%s%s%s%s%s\nISA Extn\t: ",
290 		       IS_AVAIL1(cpu->extn.timer0, "Timer0 "),
291 		       IS_AVAIL1(cpu->extn.timer1, "Timer1 "),
292 		       IS_AVAIL2(cpu->extn.rtc, "RTC [UP 64-bit] ", CONFIG_ARC_TIMERS_64BIT),
293 		       IS_AVAIL2(cpu->extn.gfrc, "GFRC [SMP 64-bit] ", CONFIG_ARC_TIMERS_64BIT));
294 
295 	if (cpu->extn_mpy.ver) {
296 		if (is_isa_arcompact()) {
297 			scnprintf(mpy_opt, 16, "mpy");
298 		} else {
299 
300 			int opt = 2;	/* stock MPY/MPYH */
301 
302 			if (cpu->extn_mpy.dsp)	/* OPT 7-9 */
303 				opt = cpu->extn_mpy.dsp + 6;
304 
305 			scnprintf(mpy_opt, 16, "mpy[opt %d] ", opt);
306 		}
307 	}
308 
309 	n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s%s%s\n",
310 		       IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
311 		       IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
312 		       IS_AVAIL2(cpu->isa.unalign, "unalign ", CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS),
313 		       IS_AVAIL1(cpu->extn_mpy.ver, mpy_opt),
314 		       IS_AVAIL1(cpu->isa.div_rem, "div_rem "));
315 
316 	if (cpu->bpu.ver) {
317 		n += scnprintf(buf + n, len - n,
318 			      "BPU\t\t: %s%s match, cache:%d, Predict Table:%d Return stk: %d",
319 			      IS_AVAIL1(cpu->bpu.full, "full"),
320 			      IS_AVAIL1(!cpu->bpu.full, "partial"),
321 			      cpu->bpu.num_cache, cpu->bpu.num_pred, cpu->bpu.ret_stk);
322 
323 		if (is_isa_arcv2()) {
324 			struct bcr_lpb lpb;
325 
326 			READ_BCR(ARC_REG_LPB_BUILD, lpb);
327 			if (lpb.ver) {
328 				unsigned int ctl;
329 				ctl = read_aux_reg(ARC_REG_LPB_CTRL);
330 
331 				n += scnprintf(buf + n, len - n, " Loop Buffer:%d %s",
332 					       lpb.entries,
333 					       IS_DISABLED_RUN(!ctl));
334 			}
335 		}
336 		n += scnprintf(buf + n, len - n, "\n");
337 	}
338 
339 	return buf;
340 }
341 
342 static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
343 {
344 	int n = 0;
345 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
346 
347 	FIX_PTR(cpu);
348 
349 	n += scnprintf(buf + n, len - n, "Vector Table\t: %#x\n", cpu->vec_base);
350 
351 	if (cpu->extn.fpu_sp || cpu->extn.fpu_dp)
352 		n += scnprintf(buf + n, len - n, "FPU\t\t: %s%s\n",
353 			       IS_AVAIL1(cpu->extn.fpu_sp, "SP "),
354 			       IS_AVAIL1(cpu->extn.fpu_dp, "DP "));
355 
356 	if (cpu->extn.ap_num | cpu->extn.smart | cpu->extn.rtt) {
357 		n += scnprintf(buf + n, len - n, "DEBUG\t\t: %s%s",
358 			       IS_AVAIL1(cpu->extn.smart, "smaRT "),
359 			       IS_AVAIL1(cpu->extn.rtt, "RTT "));
360 		if (cpu->extn.ap_num) {
361 			n += scnprintf(buf + n, len - n, "ActionPoint %d/%s",
362 				       cpu->extn.ap_num,
363 				       cpu->extn.ap_full ? "full":"min");
364 		}
365 		n += scnprintf(buf + n, len - n, "\n");
366 	}
367 
368 	if (cpu->dccm.sz || cpu->iccm.sz)
369 		n += scnprintf(buf + n, len - n, "Extn [CCM]\t: DCCM @ %x, %d KB / ICCM: @ %x, %d KB\n",
370 			       cpu->dccm.base_addr, TO_KB(cpu->dccm.sz),
371 			       cpu->iccm.base_addr, TO_KB(cpu->iccm.sz));
372 
373 	if (is_isa_arcv2()) {
374 
375 		/* Error Protection: ECC/Parity */
376 		struct bcr_erp erp;
377 		READ_BCR(ARC_REG_ERP_BUILD, erp);
378 
379 		if (erp.ver) {
380 			struct  ctl_erp ctl;
381 			READ_BCR(ARC_REG_ERP_CTRL, ctl);
382 
383 			/* inverted bits: 0 means enabled */
384 			n += scnprintf(buf + n, len - n, "Extn [ECC]\t: %s%s%s%s%s%s\n",
385 				IS_AVAIL3(erp.ic,  !ctl.dpi, "IC "),
386 				IS_AVAIL3(erp.dc,  !ctl.dpd, "DC "),
387 				IS_AVAIL3(erp.mmu, !ctl.mpd, "MMU "));
388 		}
389 	}
390 
391 	return buf;
392 }
393 
394 void chk_opt_strict(char *opt_name, bool hw_exists, bool opt_ena)
395 {
396 	if (hw_exists && !opt_ena)
397 		pr_warn(" ! Enable %s for working apps\n", opt_name);
398 	else if (!hw_exists && opt_ena)
399 		panic("Disable %s, hardware NOT present\n", opt_name);
400 }
401 
402 void chk_opt_weak(char *opt_name, bool hw_exists, bool opt_ena)
403 {
404 	if (!hw_exists && opt_ena)
405 		panic("Disable %s, hardware NOT present\n", opt_name);
406 }
407 
408 static void arc_chk_core_config(void)
409 {
410 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
411 	int present = 0;
412 
413 	if (!cpu->extn.timer0)
414 		panic("Timer0 is not present!\n");
415 
416 	if (!cpu->extn.timer1)
417 		panic("Timer1 is not present!\n");
418 
419 #ifdef CONFIG_ARC_HAS_DCCM
420 	/*
421 	 * DCCM can be arbit placed in hardware.
422 	 * Make sure it's placement/sz matches what Linux is built with
423 	 */
424 	if ((unsigned int)__arc_dccm_base != cpu->dccm.base_addr)
425 		panic("Linux built with incorrect DCCM Base address\n");
426 
427 	if (CONFIG_ARC_DCCM_SZ != cpu->dccm.sz)
428 		panic("Linux built with incorrect DCCM Size\n");
429 #endif
430 
431 #ifdef CONFIG_ARC_HAS_ICCM
432 	if (CONFIG_ARC_ICCM_SZ != cpu->iccm.sz)
433 		panic("Linux built with incorrect ICCM Size\n");
434 #endif
435 
436 	/*
437 	 * FP hardware/software config sanity
438 	 * -If hardware present, kernel needs to save/restore FPU state
439 	 * -If not, it will crash trying to save/restore the non-existant regs
440 	 */
441 
442 	if (is_isa_arcompact()) {
443 		/* only DPDP checked since SP has no arch visible regs */
444 		present = cpu->extn.fpu_dp;
445 		CHK_OPT_STRICT(CONFIG_ARC_FPU_SAVE_RESTORE, present);
446 	} else {
447 		/* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */
448 		present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp;
449 		CHK_OPT_STRICT(CONFIG_ARC_HAS_ACCL_REGS, present);
450 
451 		dsp_config_check();
452 	}
453 }
454 
455 /*
456  * Initialize and setup the processor core
457  * This is called by all the CPUs thus should not do special case stuff
458  *    such as only for boot CPU etc
459  */
460 
461 void setup_processor(void)
462 {
463 	char str[512];
464 	int cpu_id = smp_processor_id();
465 
466 	read_arc_build_cfg_regs();
467 	arc_init_IRQ();
468 
469 	pr_info("%s", arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));
470 
471 	arc_mmu_init();
472 	arc_cache_init();
473 
474 	pr_info("%s", arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));
475 	pr_info("%s", arc_platform_smp_cpuinfo());
476 
477 	arc_chk_core_config();
478 }
479 
480 static inline bool uboot_arg_invalid(unsigned long addr)
481 {
482 	/*
483 	 * Check that it is a untranslated address (although MMU is not enabled
484 	 * yet, it being a high address ensures this is not by fluke)
485 	 */
486 	if (addr < PAGE_OFFSET)
487 		return true;
488 
489 	/* Check that address doesn't clobber resident kernel image */
490 	return addr >= (unsigned long)_stext && addr <= (unsigned long)_end;
491 }
492 
493 #define IGNORE_ARGS		"Ignore U-boot args: "
494 
495 /* uboot_tag values for U-boot - kernel ABI revision 0; see head.S */
496 #define UBOOT_TAG_NONE		0
497 #define UBOOT_TAG_CMDLINE	1
498 #define UBOOT_TAG_DTB		2
499 /* We always pass 0 as magic from U-boot */
500 #define UBOOT_MAGIC_VALUE	0
501 
502 void __init handle_uboot_args(void)
503 {
504 	bool use_embedded_dtb = true;
505 	bool append_cmdline = false;
506 
507 	/* check that we know this tag */
508 	if (uboot_tag != UBOOT_TAG_NONE &&
509 	    uboot_tag != UBOOT_TAG_CMDLINE &&
510 	    uboot_tag != UBOOT_TAG_DTB) {
511 		pr_warn(IGNORE_ARGS "invalid uboot tag: '%08x'\n", uboot_tag);
512 		goto ignore_uboot_args;
513 	}
514 
515 	if (uboot_magic != UBOOT_MAGIC_VALUE) {
516 		pr_warn(IGNORE_ARGS "non zero uboot magic\n");
517 		goto ignore_uboot_args;
518 	}
519 
520 	if (uboot_tag != UBOOT_TAG_NONE &&
521             uboot_arg_invalid((unsigned long)uboot_arg)) {
522 		pr_warn(IGNORE_ARGS "invalid uboot arg: '%px'\n", uboot_arg);
523 		goto ignore_uboot_args;
524 	}
525 
526 	/* see if U-boot passed an external Device Tree blob */
527 	if (uboot_tag == UBOOT_TAG_DTB) {
528 		machine_desc = setup_machine_fdt((void *)uboot_arg);
529 
530 		/* external Device Tree blob is invalid - use embedded one */
531 		use_embedded_dtb = !machine_desc;
532 	}
533 
534 	if (uboot_tag == UBOOT_TAG_CMDLINE)
535 		append_cmdline = true;
536 
537 ignore_uboot_args:
538 
539 	if (use_embedded_dtb) {
540 		machine_desc = setup_machine_fdt(__dtb_start);
541 		if (!machine_desc)
542 			panic("Embedded DT invalid\n");
543 	}
544 
545 	/*
546 	 * NOTE: @boot_command_line is populated by setup_machine_fdt() so this
547 	 * append processing can only happen after.
548 	 */
549 	if (append_cmdline) {
550 		/* Ensure a whitespace between the 2 cmdlines */
551 		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
552 		strlcat(boot_command_line, uboot_arg, COMMAND_LINE_SIZE);
553 	}
554 }
555 
556 void __init setup_arch(char **cmdline_p)
557 {
558 	handle_uboot_args();
559 
560 	/* Save unparsed command line copy for /proc/cmdline */
561 	*cmdline_p = boot_command_line;
562 
563 	/* To force early parsing of things like mem=xxx */
564 	parse_early_param();
565 
566 	/* Platform/board specific: e.g. early console registration */
567 	if (machine_desc->init_early)
568 		machine_desc->init_early();
569 
570 	smp_init_cpus();
571 
572 	setup_processor();
573 	setup_arch_memory();
574 
575 	/* copy flat DT out of .init and then unflatten it */
576 	unflatten_and_copy_device_tree();
577 
578 	/* Can be issue if someone passes cmd line arg "ro"
579 	 * But that is unlikely so keeping it as it is
580 	 */
581 	root_mountflags &= ~MS_RDONLY;
582 
583 	arc_unwind_init();
584 }
585 
586 /*
587  * Called from start_kernel() - boot CPU only
588  */
589 void __init time_init(void)
590 {
591 	of_clk_init(NULL);
592 	timer_probe();
593 }
594 
595 static int __init customize_machine(void)
596 {
597 	if (machine_desc->init_machine)
598 		machine_desc->init_machine();
599 
600 	return 0;
601 }
602 arch_initcall(customize_machine);
603 
604 static int __init init_late_machine(void)
605 {
606 	if (machine_desc->init_late)
607 		machine_desc->init_late();
608 
609 	return 0;
610 }
611 late_initcall(init_late_machine);
612 /*
613  *  Get CPU information for use by the procfs.
614  */
615 
616 #define cpu_to_ptr(c)	((void *)(0xFFFF0000 | (unsigned int)(c)))
617 #define ptr_to_cpu(p)	(~0xFFFF0000UL & (unsigned int)(p))
618 
619 static int show_cpuinfo(struct seq_file *m, void *v)
620 {
621 	char *str;
622 	int cpu_id = ptr_to_cpu(v);
623 	struct device *cpu_dev = get_cpu_device(cpu_id);
624 	struct clk *cpu_clk;
625 	unsigned long freq = 0;
626 
627 	if (!cpu_online(cpu_id)) {
628 		seq_printf(m, "processor [%d]\t: Offline\n", cpu_id);
629 		goto done;
630 	}
631 
632 	str = (char *)__get_free_page(GFP_KERNEL);
633 	if (!str)
634 		goto done;
635 
636 	seq_printf(m, arc_cpu_mumbojumbo(cpu_id, str, PAGE_SIZE));
637 
638 	cpu_clk = clk_get(cpu_dev, NULL);
639 	if (IS_ERR(cpu_clk)) {
640 		seq_printf(m, "CPU speed \t: Cannot get clock for processor [%d]\n",
641 			   cpu_id);
642 	} else {
643 		freq = clk_get_rate(cpu_clk);
644 	}
645 	if (freq)
646 		seq_printf(m, "CPU speed\t: %lu.%02lu Mhz\n",
647 			   freq / 1000000, (freq / 10000) % 100);
648 
649 	seq_printf(m, "Bogo MIPS\t: %lu.%02lu\n",
650 		   loops_per_jiffy / (500000 / HZ),
651 		   (loops_per_jiffy / (5000 / HZ)) % 100);
652 
653 	seq_printf(m, arc_mmu_mumbojumbo(cpu_id, str, PAGE_SIZE));
654 	seq_printf(m, arc_cache_mumbojumbo(cpu_id, str, PAGE_SIZE));
655 	seq_printf(m, arc_extn_mumbojumbo(cpu_id, str, PAGE_SIZE));
656 	seq_printf(m, arc_platform_smp_cpuinfo());
657 
658 	free_page((unsigned long)str);
659 done:
660 	seq_printf(m, "\n");
661 
662 	return 0;
663 }
664 
665 static void *c_start(struct seq_file *m, loff_t *pos)
666 {
667 	/*
668 	 * Callback returns cpu-id to iterator for show routine, NULL to stop.
669 	 * However since NULL is also a valid cpu-id (0), we use a round-about
670 	 * way to pass it w/o having to kmalloc/free a 2 byte string.
671 	 * Encode cpu-id as 0xFFcccc, which is decoded by show routine.
672 	 */
673 	return *pos < nr_cpu_ids ? cpu_to_ptr(*pos) : NULL;
674 }
675 
676 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
677 {
678 	++*pos;
679 	return c_start(m, pos);
680 }
681 
682 static void c_stop(struct seq_file *m, void *v)
683 {
684 }
685 
686 const struct seq_operations cpuinfo_op = {
687 	.start	= c_start,
688 	.next	= c_next,
689 	.stop	= c_stop,
690 	.show	= show_cpuinfo
691 };
692 
693 static DEFINE_PER_CPU(struct cpu, cpu_topology);
694 
695 static int __init topology_init(void)
696 {
697 	int cpu;
698 
699 	for_each_present_cpu(cpu)
700 	    register_cpu(&per_cpu(cpu_topology, cpu), cpu);
701 
702 	return 0;
703 }
704 
705 subsys_initcall(topology_init);
706