xref: /linux-6.15/arch/arc/kernel/setup.c (revision 00a4ae65)
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 <uapi/linux/mount.h>
23 #include <asm/sections.h>
24 #include <asm/arcregs.h>
25 #include <asm/tlb.h>
26 #include <asm/setup.h>
27 #include <asm/page.h>
28 #include <asm/irq.h>
29 #include <asm/unwind.h>
30 #include <asm/mach_desc.h>
31 #include <asm/smp.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_cpu_rel[] = {
62 	/* UARCH.MAJOR,	Release */
63 	{  0,		"R3.10a"},
64 	{  1,		"R3.50a"},
65 	{  0xFF,	NULL   }
66 };
67 
68 static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
69 {
70 	if (is_isa_arcompact()) {
71 		struct bcr_iccm_arcompact iccm;
72 		struct bcr_dccm_arcompact dccm;
73 
74 		READ_BCR(ARC_REG_ICCM_BUILD, iccm);
75 		if (iccm.ver) {
76 			cpu->iccm.sz = 4096 << iccm.sz;	/* 8K to 512K */
77 			cpu->iccm.base_addr = iccm.base << 16;
78 		}
79 
80 		READ_BCR(ARC_REG_DCCM_BUILD, dccm);
81 		if (dccm.ver) {
82 			unsigned long base;
83 			cpu->dccm.sz = 2048 << dccm.sz;	/* 2K to 256K */
84 
85 			base = read_aux_reg(ARC_REG_DCCM_BASE_BUILD);
86 			cpu->dccm.base_addr = base & ~0xF;
87 		}
88 	} else {
89 		struct bcr_iccm_arcv2 iccm;
90 		struct bcr_dccm_arcv2 dccm;
91 		unsigned long region;
92 
93 		READ_BCR(ARC_REG_ICCM_BUILD, iccm);
94 		if (iccm.ver) {
95 			cpu->iccm.sz = 256 << iccm.sz00;	/* 512B to 16M */
96 			if (iccm.sz00 == 0xF && iccm.sz01 > 0)
97 				cpu->iccm.sz <<= iccm.sz01;
98 
99 			region = read_aux_reg(ARC_REG_AUX_ICCM);
100 			cpu->iccm.base_addr = region & 0xF0000000;
101 		}
102 
103 		READ_BCR(ARC_REG_DCCM_BUILD, dccm);
104 		if (dccm.ver) {
105 			cpu->dccm.sz = 256 << dccm.sz0;
106 			if (dccm.sz0 == 0xF && dccm.sz1 > 0)
107 				cpu->dccm.sz <<= dccm.sz1;
108 
109 			region = read_aux_reg(ARC_REG_AUX_DCCM);
110 			cpu->dccm.base_addr = region & 0xF0000000;
111 		}
112 	}
113 }
114 
115 static void decode_arc_core(struct cpuinfo_arc *cpu)
116 {
117 	struct bcr_uarch_build_arcv2 uarch;
118 	const struct id_to_str *tbl;
119 
120 	/*
121 	 * Up until (including) the first core4 release (0x54) things were
122 	 * simple: AUX IDENTITY.ARCVER was sufficient to identify arc family
123 	 * and release: 0x50 to 0x53 was HS38, 0x54 was HS48 (dual issue)
124 	 */
125 
126 	if (cpu->core.family < 0x54) { /* includes arc700 */
127 
128 		for (tbl = &arc_legacy_rel[0]; tbl->id != 0; tbl++) {
129 			if (cpu->core.family == tbl->id) {
130 				cpu->release = tbl->str;
131 				break;
132 			}
133 		}
134 
135 		if (is_isa_arcompact())
136 			cpu->name = "ARC700";
137 		else if (tbl->str)
138 			cpu->name = "HS38";
139 		else
140 			cpu->name = cpu->release = "Unknown";
141 
142 		return;
143 	}
144 
145 	/*
146 	 * However the subsequent HS release (same 0x54) allow HS38 or HS48
147 	 * configurations and encode this info in a different BCR.
148 	 * The BCR was introduced in 0x54 so can't be read unconditionally.
149 	 */
150 
151 	READ_BCR(ARC_REG_MICRO_ARCH_BCR, uarch);
152 
153 	if (uarch.prod == 4) {
154 		cpu->name = "HS48";
155 		cpu->extn.dual = 1;
156 
157 	} else {
158 		cpu->name = "HS38";
159 	}
160 
161 	for (tbl = &arc_cpu_rel[0]; tbl->id != 0xFF; tbl++) {
162 		if (uarch.maj == tbl->id) {
163 			cpu->release = tbl->str;
164 			break;
165 		}
166 	}
167 }
168 
169 static void read_arc_build_cfg_regs(void)
170 {
171 	struct bcr_timer timer;
172 	struct bcr_generic bcr;
173 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
174 	struct bcr_isa_arcv2 isa;
175 	struct bcr_actionpoint ap;
176 
177 	FIX_PTR(cpu);
178 
179 	READ_BCR(AUX_IDENTITY, cpu->core);
180 	decode_arc_core(cpu);
181 
182 	READ_BCR(ARC_REG_TIMERS_BCR, timer);
183 	cpu->extn.timer0 = timer.t0;
184 	cpu->extn.timer1 = timer.t1;
185 	cpu->extn.rtc = timer.rtc;
186 
187 	cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);
188 
189 	READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);
190 
191 	cpu->extn.norm = read_aux_reg(ARC_REG_NORM_BCR) > 1 ? 1 : 0; /* 2,3 */
192 	cpu->extn.barrel = read_aux_reg(ARC_REG_BARREL_BCR) > 1 ? 1 : 0; /* 2,3 */
193 	cpu->extn.swap = read_aux_reg(ARC_REG_SWAP_BCR) ? 1 : 0;        /* 1,3 */
194 	cpu->extn.crc = read_aux_reg(ARC_REG_CRC_BCR) ? 1 : 0;
195 	cpu->extn.minmax = read_aux_reg(ARC_REG_MIXMAX_BCR) > 1 ? 1 : 0; /* 2 */
196 	cpu->extn.swape = (cpu->core.family >= 0x34) ? 1 :
197 				IS_ENABLED(CONFIG_ARC_HAS_SWAPE);
198 
199 	READ_BCR(ARC_REG_XY_MEM_BCR, cpu->extn_xymem);
200 
201 	/* Read CCM BCRs for boot reporting even if not enabled in Kconfig */
202 	read_decode_ccm_bcr(cpu);
203 
204 	read_decode_mmu_bcr();
205 	read_decode_cache_bcr();
206 
207 	if (is_isa_arcompact()) {
208 		struct bcr_fp_arcompact sp, dp;
209 		struct bcr_bpu_arcompact bpu;
210 
211 		READ_BCR(ARC_REG_FP_BCR, sp);
212 		READ_BCR(ARC_REG_DPFP_BCR, dp);
213 		cpu->extn.fpu_sp = sp.ver ? 1 : 0;
214 		cpu->extn.fpu_dp = dp.ver ? 1 : 0;
215 
216 		READ_BCR(ARC_REG_BPU_BCR, bpu);
217 		cpu->bpu.ver = bpu.ver;
218 		cpu->bpu.full = bpu.fam ? 1 : 0;
219 		if (bpu.ent) {
220 			cpu->bpu.num_cache = 256 << (bpu.ent - 1);
221 			cpu->bpu.num_pred = 256 << (bpu.ent - 1);
222 		}
223 	} else {
224 		struct bcr_fp_arcv2 spdp;
225 		struct bcr_bpu_arcv2 bpu;
226 
227 		READ_BCR(ARC_REG_FP_V2_BCR, spdp);
228 		cpu->extn.fpu_sp = spdp.sp ? 1 : 0;
229 		cpu->extn.fpu_dp = spdp.dp ? 1 : 0;
230 
231 		READ_BCR(ARC_REG_BPU_BCR, bpu);
232 		cpu->bpu.ver = bpu.ver;
233 		cpu->bpu.full = bpu.ft;
234 		cpu->bpu.num_cache = 256 << bpu.bce;
235 		cpu->bpu.num_pred = 2048 << bpu.pte;
236 		cpu->bpu.ret_stk = 4 << bpu.rse;
237 
238 		/* if dual issue hardware, is it enabled ? */
239 		if (cpu->extn.dual) {
240 			unsigned int exec_ctrl;
241 
242 			READ_BCR(AUX_EXEC_CTRL, exec_ctrl);
243 			cpu->extn.dual_enb = !(exec_ctrl & 1);
244 		}
245 	}
246 
247 	READ_BCR(ARC_REG_AP_BCR, ap);
248 	if (ap.ver) {
249 		cpu->extn.ap_num = 2 << ap.num;
250 		cpu->extn.ap_full = !ap.min;
251 	}
252 
253 	READ_BCR(ARC_REG_SMART_BCR, bcr);
254 	cpu->extn.smart = bcr.ver ? 1 : 0;
255 
256 	READ_BCR(ARC_REG_RTT_BCR, bcr);
257 	cpu->extn.rtt = bcr.ver ? 1 : 0;
258 
259 	READ_BCR(ARC_REG_ISA_CFG_BCR, isa);
260 
261 	/* some hacks for lack of feature BCR info in old ARC700 cores */
262 	if (is_isa_arcompact()) {
263 		if (!isa.ver)	/* ISA BCR absent, use Kconfig info */
264 			cpu->isa.atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
265 		else {
266 			/* ARC700_BUILD only has 2 bits of isa info */
267 			struct bcr_generic bcr = *(struct bcr_generic *)&isa;
268 			cpu->isa.atomic = bcr.info & 1;
269 		}
270 
271 		cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
272 
273 		 /* there's no direct way to distinguish 750 vs. 770 */
274 		if (unlikely(cpu->core.family < 0x34 || cpu->mmu.ver < 3))
275 			cpu->name = "ARC750";
276 	} else {
277 		cpu->isa = isa;
278 	}
279 }
280 
281 static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
282 {
283 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
284 	struct bcr_identity *core = &cpu->core;
285 	int n = 0;
286 
287 	FIX_PTR(cpu);
288 
289 	n += scnprintf(buf + n, len - n,
290 		       "\nIDENTITY\t: ARCVER [%#02x] ARCNUM [%#02x] CHIPID [%#4x]\n",
291 		       core->family, core->cpu_id, core->chip_id);
292 
293 	n += scnprintf(buf + n, len - n, "processor [%d]\t: %s %s (%s ISA) %s%s%s\n",
294 		       cpu_id, cpu->name, cpu->release,
295 		       is_isa_arcompact() ? "ARCompact" : "ARCv2",
296 		       IS_AVAIL1(cpu->isa.be, "[Big-Endian]"),
297 		       IS_AVAIL3(cpu->extn.dual, cpu->extn.dual_enb, " Dual-Issue "));
298 
299 	n += scnprintf(buf + n, len - n, "Timers\t\t: %s%s%s%s%s%s\nISA Extn\t: ",
300 		       IS_AVAIL1(cpu->extn.timer0, "Timer0 "),
301 		       IS_AVAIL1(cpu->extn.timer1, "Timer1 "),
302 		       IS_AVAIL2(cpu->extn.rtc, "RTC [UP 64-bit] ", CONFIG_ARC_TIMERS_64BIT),
303 		       IS_AVAIL2(cpu->extn.gfrc, "GFRC [SMP 64-bit] ", CONFIG_ARC_TIMERS_64BIT));
304 
305 	n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s",
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 
310 #if defined(__ARC_UNALIGNED__) && !defined(CONFIG_ARC_USE_UNALIGNED_MEM_ACCESS)
311 	/*
312 	 * gcc 7.3.1 (GNU 2018.03) onwards generate unaligned access by default
313 	 * but -mno-unaligned-access to disable that didn't work until gcc 8.2.1
314 	 * (GNU 2019.03). So landing here implies the interim period, when
315 	 * despite Kconfig being off, gcc is generating unaligned accesses which
316 	 * could bomb later on. So better to disallow such broken builds
317 	 */
318 	BUILD_BUG_ON_MSG(1, "gcc doesn't support -mno-unaligned-access");
319 #endif
320 
321 	n += scnprintf(buf + n, len - n, "\n\t\t: ");
322 
323 	if (cpu->extn_mpy.ver) {
324 		if (cpu->extn_mpy.ver <= 0x2) {	/* ARCompact */
325 			n += scnprintf(buf + n, len - n, "mpy ");
326 		} else {
327 			int opt = 2;	/* stock MPY/MPYH */
328 
329 			if (cpu->extn_mpy.dsp)	/* OPT 7-9 */
330 				opt = cpu->extn_mpy.dsp + 6;
331 
332 			n += scnprintf(buf + n, len - n, "mpy[opt %d] ", opt);
333 		}
334 	}
335 
336 	n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s%s%s\n",
337 		       IS_AVAIL1(cpu->isa.div_rem, "div_rem "),
338 		       IS_AVAIL1(cpu->extn.norm, "norm "),
339 		       IS_AVAIL1(cpu->extn.barrel, "barrel-shift "),
340 		       IS_AVAIL1(cpu->extn.swap, "swap "),
341 		       IS_AVAIL1(cpu->extn.minmax, "minmax "),
342 		       IS_AVAIL1(cpu->extn.crc, "crc "),
343 		       IS_AVAIL2(cpu->extn.swape, "swape", CONFIG_ARC_HAS_SWAPE));
344 
345 	if (cpu->bpu.ver)
346 		n += scnprintf(buf + n, len - n,
347 			      "BPU\t\t: %s%s match, cache:%d, Predict Table:%d Return stk: %d",
348 			      IS_AVAIL1(cpu->bpu.full, "full"),
349 			      IS_AVAIL1(!cpu->bpu.full, "partial"),
350 			      cpu->bpu.num_cache, cpu->bpu.num_pred, cpu->bpu.ret_stk);
351 
352 	if (is_isa_arcv2()) {
353 		struct bcr_lpb lpb;
354 
355 		READ_BCR(ARC_REG_LPB_BUILD, lpb);
356 		if (lpb.ver) {
357 			unsigned int ctl;
358 			ctl = read_aux_reg(ARC_REG_LPB_CTRL);
359 
360 			n += scnprintf(buf + n, len - n, " Loop Buffer:%d %s",
361 				lpb.entries,
362 				IS_DISABLED_RUN(!ctl));
363 		}
364 	}
365 
366 	n += scnprintf(buf + n, len - n, "\n");
367 	return buf;
368 }
369 
370 static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
371 {
372 	int n = 0;
373 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
374 
375 	FIX_PTR(cpu);
376 
377 	n += scnprintf(buf + n, len - n, "Vector Table\t: %#x\n", cpu->vec_base);
378 
379 	if (cpu->extn.fpu_sp || cpu->extn.fpu_dp)
380 		n += scnprintf(buf + n, len - n, "FPU\t\t: %s%s\n",
381 			       IS_AVAIL1(cpu->extn.fpu_sp, "SP "),
382 			       IS_AVAIL1(cpu->extn.fpu_dp, "DP "));
383 
384 	if (cpu->extn.ap_num | cpu->extn.smart | cpu->extn.rtt) {
385 		n += scnprintf(buf + n, len - n, "DEBUG\t\t: %s%s",
386 			       IS_AVAIL1(cpu->extn.smart, "smaRT "),
387 			       IS_AVAIL1(cpu->extn.rtt, "RTT "));
388 		if (cpu->extn.ap_num) {
389 			n += scnprintf(buf + n, len - n, "ActionPoint %d/%s",
390 				       cpu->extn.ap_num,
391 				       cpu->extn.ap_full ? "full":"min");
392 		}
393 		n += scnprintf(buf + n, len - n, "\n");
394 	}
395 
396 	if (cpu->dccm.sz || cpu->iccm.sz)
397 		n += scnprintf(buf + n, len - n, "Extn [CCM]\t: DCCM @ %x, %d KB / ICCM: @ %x, %d KB\n",
398 			       cpu->dccm.base_addr, TO_KB(cpu->dccm.sz),
399 			       cpu->iccm.base_addr, TO_KB(cpu->iccm.sz));
400 
401 	if (is_isa_arcv2()) {
402 
403 		/* Error Protection: ECC/Parity */
404 		struct bcr_erp erp;
405 		READ_BCR(ARC_REG_ERP_BUILD, erp);
406 
407 		if (erp.ver) {
408 			struct  ctl_erp ctl;
409 			READ_BCR(ARC_REG_ERP_CTRL, ctl);
410 
411 			/* inverted bits: 0 means enabled */
412 			n += scnprintf(buf + n, len - n, "Extn [ECC]\t: %s%s%s%s%s%s\n",
413 				IS_AVAIL3(erp.ic,  !ctl.dpi, "IC "),
414 				IS_AVAIL3(erp.dc,  !ctl.dpd, "DC "),
415 				IS_AVAIL3(erp.mmu, !ctl.mpd, "MMU "));
416 		}
417 	}
418 
419 	n += scnprintf(buf + n, len - n, "OS ABI [v%d]\t: %s\n",
420 			EF_ARC_OSABI_CURRENT >> 8,
421 			EF_ARC_OSABI_CURRENT == EF_ARC_OSABI_V3 ?
422 			"no-legacy-syscalls" : "64-bit data any register aligned");
423 
424 	return buf;
425 }
426 
427 static void arc_chk_core_config(void)
428 {
429 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
430 	int saved = 0, present = 0;
431 	char *opt_nm = NULL;
432 
433 	if (!cpu->extn.timer0)
434 		panic("Timer0 is not present!\n");
435 
436 	if (!cpu->extn.timer1)
437 		panic("Timer1 is not present!\n");
438 
439 #ifdef CONFIG_ARC_HAS_DCCM
440 	/*
441 	 * DCCM can be arbit placed in hardware.
442 	 * Make sure it's placement/sz matches what Linux is built with
443 	 */
444 	if ((unsigned int)__arc_dccm_base != cpu->dccm.base_addr)
445 		panic("Linux built with incorrect DCCM Base address\n");
446 
447 	if (CONFIG_ARC_DCCM_SZ != cpu->dccm.sz)
448 		panic("Linux built with incorrect DCCM Size\n");
449 #endif
450 
451 #ifdef CONFIG_ARC_HAS_ICCM
452 	if (CONFIG_ARC_ICCM_SZ != cpu->iccm.sz)
453 		panic("Linux built with incorrect ICCM Size\n");
454 #endif
455 
456 	/*
457 	 * FP hardware/software config sanity
458 	 * -If hardware present, kernel needs to save/restore FPU state
459 	 * -If not, it will crash trying to save/restore the non-existant regs
460 	 */
461 
462 	if (is_isa_arcompact()) {
463 		opt_nm = "CONFIG_ARC_FPU_SAVE_RESTORE";
464 		saved = IS_ENABLED(CONFIG_ARC_FPU_SAVE_RESTORE);
465 
466 		/* only DPDP checked since SP has no arch visible regs */
467 		present = cpu->extn.fpu_dp;
468 	} else {
469 		opt_nm = "CONFIG_ARC_HAS_ACCL_REGS";
470 		saved = IS_ENABLED(CONFIG_ARC_HAS_ACCL_REGS);
471 
472 		/* Accumulator Low:High pair (r58:59) present if DSP MPY or FPU */
473 		present = cpu->extn_mpy.dsp | cpu->extn.fpu_sp | cpu->extn.fpu_dp;
474 	}
475 
476 	if (present && !saved)
477 		pr_warn("Enable %s for working apps\n", opt_nm);
478 	else if (!present && saved)
479 		panic("Disable %s, hardware NOT present\n", opt_nm);
480 }
481 
482 /*
483  * Initialize and setup the processor core
484  * This is called by all the CPUs thus should not do special case stuff
485  *    such as only for boot CPU etc
486  */
487 
488 void setup_processor(void)
489 {
490 	char str[512];
491 	int cpu_id = smp_processor_id();
492 
493 	read_arc_build_cfg_regs();
494 	arc_init_IRQ();
495 
496 	pr_info("%s", arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));
497 
498 	arc_mmu_init();
499 	arc_cache_init();
500 
501 	pr_info("%s", arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));
502 	pr_info("%s", arc_platform_smp_cpuinfo());
503 
504 	arc_chk_core_config();
505 }
506 
507 static inline bool uboot_arg_invalid(unsigned long addr)
508 {
509 	/*
510 	 * Check that it is a untranslated address (although MMU is not enabled
511 	 * yet, it being a high address ensures this is not by fluke)
512 	 */
513 	if (addr < PAGE_OFFSET)
514 		return true;
515 
516 	/* Check that address doesn't clobber resident kernel image */
517 	return addr >= (unsigned long)_stext && addr <= (unsigned long)_end;
518 }
519 
520 #define IGNORE_ARGS		"Ignore U-boot args: "
521 
522 /* uboot_tag values for U-boot - kernel ABI revision 0; see head.S */
523 #define UBOOT_TAG_NONE		0
524 #define UBOOT_TAG_CMDLINE	1
525 #define UBOOT_TAG_DTB		2
526 /* We always pass 0 as magic from U-boot */
527 #define UBOOT_MAGIC_VALUE	0
528 
529 void __init handle_uboot_args(void)
530 {
531 	bool use_embedded_dtb = true;
532 	bool append_cmdline = false;
533 
534 	/* check that we know this tag */
535 	if (uboot_tag != UBOOT_TAG_NONE &&
536 	    uboot_tag != UBOOT_TAG_CMDLINE &&
537 	    uboot_tag != UBOOT_TAG_DTB) {
538 		pr_warn(IGNORE_ARGS "invalid uboot tag: '%08x'\n", uboot_tag);
539 		goto ignore_uboot_args;
540 	}
541 
542 	if (uboot_magic != UBOOT_MAGIC_VALUE) {
543 		pr_warn(IGNORE_ARGS "non zero uboot magic\n");
544 		goto ignore_uboot_args;
545 	}
546 
547 	if (uboot_tag != UBOOT_TAG_NONE &&
548             uboot_arg_invalid((unsigned long)uboot_arg)) {
549 		pr_warn(IGNORE_ARGS "invalid uboot arg: '%px'\n", uboot_arg);
550 		goto ignore_uboot_args;
551 	}
552 
553 	/* see if U-boot passed an external Device Tree blob */
554 	if (uboot_tag == UBOOT_TAG_DTB) {
555 		machine_desc = setup_machine_fdt((void *)uboot_arg);
556 
557 		/* external Device Tree blob is invalid - use embedded one */
558 		use_embedded_dtb = !machine_desc;
559 	}
560 
561 	if (uboot_tag == UBOOT_TAG_CMDLINE)
562 		append_cmdline = true;
563 
564 ignore_uboot_args:
565 
566 	if (use_embedded_dtb) {
567 		machine_desc = setup_machine_fdt(__dtb_start);
568 		if (!machine_desc)
569 			panic("Embedded DT invalid\n");
570 	}
571 
572 	/*
573 	 * NOTE: @boot_command_line is populated by setup_machine_fdt() so this
574 	 * append processing can only happen after.
575 	 */
576 	if (append_cmdline) {
577 		/* Ensure a whitespace between the 2 cmdlines */
578 		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
579 		strlcat(boot_command_line, uboot_arg, COMMAND_LINE_SIZE);
580 	}
581 }
582 
583 void __init setup_arch(char **cmdline_p)
584 {
585 	handle_uboot_args();
586 
587 	/* Save unparsed command line copy for /proc/cmdline */
588 	*cmdline_p = boot_command_line;
589 
590 	/* To force early parsing of things like mem=xxx */
591 	parse_early_param();
592 
593 	/* Platform/board specific: e.g. early console registration */
594 	if (machine_desc->init_early)
595 		machine_desc->init_early();
596 
597 	smp_init_cpus();
598 
599 	setup_processor();
600 	setup_arch_memory();
601 
602 	/* copy flat DT out of .init and then unflatten it */
603 	unflatten_and_copy_device_tree();
604 
605 	/* Can be issue if someone passes cmd line arg "ro"
606 	 * But that is unlikely so keeping it as it is
607 	 */
608 	root_mountflags &= ~MS_RDONLY;
609 
610 #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
611 	conswitchp = &dummy_con;
612 #endif
613 
614 	arc_unwind_init();
615 }
616 
617 /*
618  * Called from start_kernel() - boot CPU only
619  */
620 void __init time_init(void)
621 {
622 	of_clk_init(NULL);
623 	timer_probe();
624 }
625 
626 static int __init customize_machine(void)
627 {
628 	if (machine_desc->init_machine)
629 		machine_desc->init_machine();
630 
631 	return 0;
632 }
633 arch_initcall(customize_machine);
634 
635 static int __init init_late_machine(void)
636 {
637 	if (machine_desc->init_late)
638 		machine_desc->init_late();
639 
640 	return 0;
641 }
642 late_initcall(init_late_machine);
643 /*
644  *  Get CPU information for use by the procfs.
645  */
646 
647 #define cpu_to_ptr(c)	((void *)(0xFFFF0000 | (unsigned int)(c)))
648 #define ptr_to_cpu(p)	(~0xFFFF0000UL & (unsigned int)(p))
649 
650 static int show_cpuinfo(struct seq_file *m, void *v)
651 {
652 	char *str;
653 	int cpu_id = ptr_to_cpu(v);
654 	struct device *cpu_dev = get_cpu_device(cpu_id);
655 	struct clk *cpu_clk;
656 	unsigned long freq = 0;
657 
658 	if (!cpu_online(cpu_id)) {
659 		seq_printf(m, "processor [%d]\t: Offline\n", cpu_id);
660 		goto done;
661 	}
662 
663 	str = (char *)__get_free_page(GFP_KERNEL);
664 	if (!str)
665 		goto done;
666 
667 	seq_printf(m, arc_cpu_mumbojumbo(cpu_id, str, PAGE_SIZE));
668 
669 	cpu_clk = clk_get(cpu_dev, NULL);
670 	if (IS_ERR(cpu_clk)) {
671 		seq_printf(m, "CPU speed \t: Cannot get clock for processor [%d]\n",
672 			   cpu_id);
673 	} else {
674 		freq = clk_get_rate(cpu_clk);
675 	}
676 	if (freq)
677 		seq_printf(m, "CPU speed\t: %lu.%02lu Mhz\n",
678 			   freq / 1000000, (freq / 10000) % 100);
679 
680 	seq_printf(m, "Bogo MIPS\t: %lu.%02lu\n",
681 		   loops_per_jiffy / (500000 / HZ),
682 		   (loops_per_jiffy / (5000 / HZ)) % 100);
683 
684 	seq_printf(m, arc_mmu_mumbojumbo(cpu_id, str, PAGE_SIZE));
685 	seq_printf(m, arc_cache_mumbojumbo(cpu_id, str, PAGE_SIZE));
686 	seq_printf(m, arc_extn_mumbojumbo(cpu_id, str, PAGE_SIZE));
687 	seq_printf(m, arc_platform_smp_cpuinfo());
688 
689 	free_page((unsigned long)str);
690 done:
691 	seq_printf(m, "\n");
692 
693 	return 0;
694 }
695 
696 static void *c_start(struct seq_file *m, loff_t *pos)
697 {
698 	/*
699 	 * Callback returns cpu-id to iterator for show routine, NULL to stop.
700 	 * However since NULL is also a valid cpu-id (0), we use a round-about
701 	 * way to pass it w/o having to kmalloc/free a 2 byte string.
702 	 * Encode cpu-id as 0xFFcccc, which is decoded by show routine.
703 	 */
704 	return *pos < nr_cpu_ids ? cpu_to_ptr(*pos) : NULL;
705 }
706 
707 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
708 {
709 	++*pos;
710 	return c_start(m, pos);
711 }
712 
713 static void c_stop(struct seq_file *m, void *v)
714 {
715 }
716 
717 const struct seq_operations cpuinfo_op = {
718 	.start	= c_start,
719 	.next	= c_next,
720 	.stop	= c_stop,
721 	.show	= show_cpuinfo
722 };
723 
724 static DEFINE_PER_CPU(struct cpu, cpu_topology);
725 
726 static int __init topology_init(void)
727 {
728 	int cpu;
729 
730 	for_each_present_cpu(cpu)
731 	    register_cpu(&per_cpu(cpu_topology, cpu), cpu);
732 
733 	return 0;
734 }
735 
736 subsys_initcall(topology_init);
737