xref: /openbmc/linux/arch/mips/kernel/setup.c (revision 2208f39c)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1995 Linus Torvalds
7  * Copyright (C) 1995 Waldorf Electronics
8  * Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 01, 02, 03  Ralf Baechle
9  * Copyright (C) 1996 Stoned Elipot
10  * Copyright (C) 1999 Silicon Graphics, Inc.
11  * Copyright (C) 2000, 2001, 2002, 2007	 Maciej W. Rozycki
12  */
13 #include <linux/init.h>
14 #include <linux/ioport.h>
15 #include <linux/export.h>
16 #include <linux/screen_info.h>
17 #include <linux/memblock.h>
18 #include <linux/initrd.h>
19 #include <linux/root_dev.h>
20 #include <linux/highmem.h>
21 #include <linux/console.h>
22 #include <linux/pfn.h>
23 #include <linux/debugfs.h>
24 #include <linux/kexec.h>
25 #include <linux/sizes.h>
26 #include <linux/device.h>
27 #include <linux/dma-map-ops.h>
28 #include <linux/decompress/generic.h>
29 #include <linux/of_fdt.h>
30 #include <linux/of_reserved_mem.h>
31 #include <linux/dmi.h>
32 
33 #include <asm/addrspace.h>
34 #include <asm/bootinfo.h>
35 #include <asm/bugs.h>
36 #include <asm/cache.h>
37 #include <asm/cdmm.h>
38 #include <asm/cpu.h>
39 #include <asm/debug.h>
40 #include <asm/dma-coherence.h>
41 #include <asm/sections.h>
42 #include <asm/setup.h>
43 #include <asm/smp-ops.h>
44 #include <asm/prom.h>
45 
46 #ifdef CONFIG_MIPS_ELF_APPENDED_DTB
47 const char __section(".appended_dtb") __appended_dtb[0x100000];
48 #endif /* CONFIG_MIPS_ELF_APPENDED_DTB */
49 
50 struct cpuinfo_mips cpu_data[NR_CPUS] __read_mostly;
51 
52 EXPORT_SYMBOL(cpu_data);
53 
54 #ifdef CONFIG_VT
55 struct screen_info screen_info;
56 #endif
57 
58 /*
59  * Setup information
60  *
61  * These are initialized so they are in the .data section
62  */
63 unsigned long mips_machtype __read_mostly = MACH_UNKNOWN;
64 
65 EXPORT_SYMBOL(mips_machtype);
66 
67 static char __initdata command_line[COMMAND_LINE_SIZE];
68 char __initdata arcs_cmdline[COMMAND_LINE_SIZE];
69 
70 #ifdef CONFIG_CMDLINE_BOOL
71 static const char builtin_cmdline[] __initconst = CONFIG_CMDLINE;
72 #else
73 static const char builtin_cmdline[] __initconst = "";
74 #endif
75 
76 /*
77  * mips_io_port_base is the begin of the address space to which x86 style
78  * I/O ports are mapped.
79  */
80 unsigned long mips_io_port_base = -1;
81 EXPORT_SYMBOL(mips_io_port_base);
82 
83 static struct resource code_resource = { .name = "Kernel code", };
84 static struct resource data_resource = { .name = "Kernel data", };
85 static struct resource bss_resource = { .name = "Kernel bss", };
86 
87 static void *detect_magic __initdata = detect_memory_region;
88 
89 #ifdef CONFIG_MIPS_AUTO_PFN_OFFSET
90 unsigned long ARCH_PFN_OFFSET;
91 EXPORT_SYMBOL(ARCH_PFN_OFFSET);
92 #endif
93 
94 void __init detect_memory_region(phys_addr_t start, phys_addr_t sz_min, phys_addr_t sz_max)
95 {
96 	void *dm = &detect_magic;
97 	phys_addr_t size;
98 
99 	for (size = sz_min; size < sz_max; size <<= 1) {
100 		if (!memcmp(dm, dm + size, sizeof(detect_magic)))
101 			break;
102 	}
103 
104 	pr_debug("Memory: %lluMB of RAM detected at 0x%llx (min: %lluMB, max: %lluMB)\n",
105 		((unsigned long long) size) / SZ_1M,
106 		(unsigned long long) start,
107 		((unsigned long long) sz_min) / SZ_1M,
108 		((unsigned long long) sz_max) / SZ_1M);
109 
110 	memblock_add(start, size);
111 }
112 
113 /*
114  * Manage initrd
115  */
116 #ifdef CONFIG_BLK_DEV_INITRD
117 
118 static int __init rd_start_early(char *p)
119 {
120 	unsigned long start = memparse(p, &p);
121 
122 #ifdef CONFIG_64BIT
123 	/* Guess if the sign extension was forgotten by bootloader */
124 	if (start < XKPHYS)
125 		start = (int)start;
126 #endif
127 	initrd_start = start;
128 	initrd_end += start;
129 	return 0;
130 }
131 early_param("rd_start", rd_start_early);
132 
133 static int __init rd_size_early(char *p)
134 {
135 	initrd_end += memparse(p, &p);
136 	return 0;
137 }
138 early_param("rd_size", rd_size_early);
139 
140 /* it returns the next free pfn after initrd */
141 static unsigned long __init init_initrd(void)
142 {
143 	unsigned long end;
144 
145 	/*
146 	 * Board specific code or command line parser should have
147 	 * already set up initrd_start and initrd_end. In these cases
148 	 * perfom sanity checks and use them if all looks good.
149 	 */
150 	if (!initrd_start || initrd_end <= initrd_start)
151 		goto disable;
152 
153 	if (initrd_start & ~PAGE_MASK) {
154 		pr_err("initrd start must be page aligned\n");
155 		goto disable;
156 	}
157 	if (initrd_start < PAGE_OFFSET) {
158 		pr_err("initrd start < PAGE_OFFSET\n");
159 		goto disable;
160 	}
161 
162 	/*
163 	 * Sanitize initrd addresses. For example firmware
164 	 * can't guess if they need to pass them through
165 	 * 64-bits values if the kernel has been built in pure
166 	 * 32-bit. We need also to switch from KSEG0 to XKPHYS
167 	 * addresses now, so the code can now safely use __pa().
168 	 */
169 	end = __pa(initrd_end);
170 	initrd_end = (unsigned long)__va(end);
171 	initrd_start = (unsigned long)__va(__pa(initrd_start));
172 
173 	ROOT_DEV = Root_RAM0;
174 	return PFN_UP(end);
175 disable:
176 	initrd_start = 0;
177 	initrd_end = 0;
178 	return 0;
179 }
180 
181 /* In some conditions (e.g. big endian bootloader with a little endian
182    kernel), the initrd might appear byte swapped.  Try to detect this and
183    byte swap it if needed.  */
184 static void __init maybe_bswap_initrd(void)
185 {
186 #if defined(CONFIG_CPU_CAVIUM_OCTEON)
187 	u64 buf;
188 
189 	/* Check for CPIO signature */
190 	if (!memcmp((void *)initrd_start, "070701", 6))
191 		return;
192 
193 	/* Check for compressed initrd */
194 	if (decompress_method((unsigned char *)initrd_start, 8, NULL))
195 		return;
196 
197 	/* Try again with a byte swapped header */
198 	buf = swab64p((u64 *)initrd_start);
199 	if (!memcmp(&buf, "070701", 6) ||
200 	    decompress_method((unsigned char *)(&buf), 8, NULL)) {
201 		unsigned long i;
202 
203 		pr_info("Byteswapped initrd detected\n");
204 		for (i = initrd_start; i < ALIGN(initrd_end, 8); i += 8)
205 			swab64s((u64 *)i);
206 	}
207 #endif
208 }
209 
210 static void __init finalize_initrd(void)
211 {
212 	unsigned long size = initrd_end - initrd_start;
213 
214 	if (size == 0) {
215 		printk(KERN_INFO "Initrd not found or empty");
216 		goto disable;
217 	}
218 	if (__pa(initrd_end) > PFN_PHYS(max_low_pfn)) {
219 		printk(KERN_ERR "Initrd extends beyond end of memory");
220 		goto disable;
221 	}
222 
223 	maybe_bswap_initrd();
224 
225 	memblock_reserve(__pa(initrd_start), size);
226 	initrd_below_start_ok = 1;
227 
228 	pr_info("Initial ramdisk at: 0x%lx (%lu bytes)\n",
229 		initrd_start, size);
230 	return;
231 disable:
232 	printk(KERN_CONT " - disabling initrd\n");
233 	initrd_start = 0;
234 	initrd_end = 0;
235 }
236 
237 #else  /* !CONFIG_BLK_DEV_INITRD */
238 
239 static unsigned long __init init_initrd(void)
240 {
241 	return 0;
242 }
243 
244 #define finalize_initrd()	do {} while (0)
245 
246 #endif
247 
248 /*
249  * Initialize the bootmem allocator. It also setup initrd related data
250  * if needed.
251  */
252 #if defined(CONFIG_SGI_IP27) || (defined(CONFIG_CPU_LOONGSON64) && defined(CONFIG_NUMA))
253 
254 static void __init bootmem_init(void)
255 {
256 	init_initrd();
257 	finalize_initrd();
258 }
259 
260 #else  /* !CONFIG_SGI_IP27 */
261 
262 static void __init bootmem_init(void)
263 {
264 	phys_addr_t ramstart, ramend;
265 	phys_addr_t start, end;
266 	u64 i;
267 
268 	ramstart = memblock_start_of_DRAM();
269 	ramend = memblock_end_of_DRAM();
270 
271 	/*
272 	 * Sanity check any INITRD first. We don't take it into account
273 	 * for bootmem setup initially, rely on the end-of-kernel-code
274 	 * as our memory range starting point. Once bootmem is inited we
275 	 * will reserve the area used for the initrd.
276 	 */
277 	init_initrd();
278 
279 	/* Reserve memory occupied by kernel. */
280 	memblock_reserve(__pa_symbol(&_text),
281 			__pa_symbol(&_end) - __pa_symbol(&_text));
282 
283 	/* max_low_pfn is not a number of pages but the end pfn of low mem */
284 
285 #ifdef CONFIG_MIPS_AUTO_PFN_OFFSET
286 	ARCH_PFN_OFFSET = PFN_UP(ramstart);
287 #else
288 	/*
289 	 * Reserve any memory between the start of RAM and PHYS_OFFSET
290 	 */
291 	if (ramstart > PHYS_OFFSET)
292 		memblock_reserve(PHYS_OFFSET, ramstart - PHYS_OFFSET);
293 
294 	if (PFN_UP(ramstart) > ARCH_PFN_OFFSET) {
295 		pr_info("Wasting %lu bytes for tracking %lu unused pages\n",
296 			(unsigned long)((PFN_UP(ramstart) - ARCH_PFN_OFFSET) * sizeof(struct page)),
297 			(unsigned long)(PFN_UP(ramstart) - ARCH_PFN_OFFSET));
298 	}
299 #endif
300 
301 	min_low_pfn = ARCH_PFN_OFFSET;
302 	max_pfn = PFN_DOWN(ramend);
303 	for_each_mem_range(i, &start, &end) {
304 		/*
305 		 * Skip highmem here so we get an accurate max_low_pfn if low
306 		 * memory stops short of high memory.
307 		 * If the region overlaps HIGHMEM_START, end is clipped so
308 		 * max_pfn excludes the highmem portion.
309 		 */
310 		if (start >= PFN_DOWN(HIGHMEM_START))
311 			continue;
312 		if (end > PFN_DOWN(HIGHMEM_START))
313 			end = PFN_DOWN(HIGHMEM_START);
314 		if (end > max_low_pfn)
315 			max_low_pfn = end;
316 	}
317 
318 	if (min_low_pfn >= max_low_pfn)
319 		panic("Incorrect memory mapping !!!");
320 
321 	if (max_pfn > PFN_DOWN(HIGHMEM_START)) {
322 #ifdef CONFIG_HIGHMEM
323 		highstart_pfn = PFN_DOWN(HIGHMEM_START);
324 		highend_pfn = max_pfn;
325 #else
326 		max_low_pfn = PFN_DOWN(HIGHMEM_START);
327 		max_pfn = max_low_pfn;
328 #endif
329 	}
330 
331 	/*
332 	 * Reserve initrd memory if needed.
333 	 */
334 	finalize_initrd();
335 }
336 
337 #endif	/* CONFIG_SGI_IP27 */
338 
339 static int usermem __initdata;
340 
341 static int __init early_parse_mem(char *p)
342 {
343 	phys_addr_t start, size;
344 
345 	/*
346 	 * If a user specifies memory size, we
347 	 * blow away any automatically generated
348 	 * size.
349 	 */
350 	if (usermem == 0) {
351 		usermem = 1;
352 		memblock_remove(memblock_start_of_DRAM(),
353 			memblock_end_of_DRAM() - memblock_start_of_DRAM());
354 	}
355 	start = 0;
356 	size = memparse(p, &p);
357 	if (*p == '@')
358 		start = memparse(p + 1, &p);
359 
360 	memblock_add(start, size);
361 
362 	return 0;
363 }
364 early_param("mem", early_parse_mem);
365 
366 static int __init early_parse_memmap(char *p)
367 {
368 	char *oldp;
369 	u64 start_at, mem_size;
370 
371 	if (!p)
372 		return -EINVAL;
373 
374 	if (!strncmp(p, "exactmap", 8)) {
375 		pr_err("\"memmap=exactmap\" invalid on MIPS\n");
376 		return 0;
377 	}
378 
379 	oldp = p;
380 	mem_size = memparse(p, &p);
381 	if (p == oldp)
382 		return -EINVAL;
383 
384 	if (*p == '@') {
385 		start_at = memparse(p+1, &p);
386 		memblock_add(start_at, mem_size);
387 	} else if (*p == '#') {
388 		pr_err("\"memmap=nn#ss\" (force ACPI data) invalid on MIPS\n");
389 		return -EINVAL;
390 	} else if (*p == '$') {
391 		start_at = memparse(p+1, &p);
392 		memblock_add(start_at, mem_size);
393 		memblock_reserve(start_at, mem_size);
394 	} else {
395 		pr_err("\"memmap\" invalid format!\n");
396 		return -EINVAL;
397 	}
398 
399 	if (*p == '\0') {
400 		usermem = 1;
401 		return 0;
402 	} else
403 		return -EINVAL;
404 }
405 early_param("memmap", early_parse_memmap);
406 
407 #ifdef CONFIG_PROC_VMCORE
408 static unsigned long setup_elfcorehdr, setup_elfcorehdr_size;
409 static int __init early_parse_elfcorehdr(char *p)
410 {
411 	phys_addr_t start, end;
412 	u64 i;
413 
414 	setup_elfcorehdr = memparse(p, &p);
415 
416 	for_each_mem_range(i, &start, &end) {
417 		if (setup_elfcorehdr >= start && setup_elfcorehdr < end) {
418 			/*
419 			 * Reserve from the elf core header to the end of
420 			 * the memory segment, that should all be kdump
421 			 * reserved memory.
422 			 */
423 			setup_elfcorehdr_size = end - setup_elfcorehdr;
424 			break;
425 		}
426 	}
427 	/*
428 	 * If we don't find it in the memory map, then we shouldn't
429 	 * have to worry about it, as the new kernel won't use it.
430 	 */
431 	return 0;
432 }
433 early_param("elfcorehdr", early_parse_elfcorehdr);
434 #endif
435 
436 #ifdef CONFIG_KEXEC
437 
438 /* 64M alignment for crash kernel regions */
439 #define CRASH_ALIGN	SZ_64M
440 #define CRASH_ADDR_MAX	SZ_512M
441 
442 static void __init mips_parse_crashkernel(void)
443 {
444 	unsigned long long total_mem;
445 	unsigned long long crash_size, crash_base;
446 	int ret;
447 
448 	total_mem = memblock_phys_mem_size();
449 	ret = parse_crashkernel(boot_command_line, total_mem,
450 				&crash_size, &crash_base);
451 	if (ret != 0 || crash_size <= 0)
452 		return;
453 
454 	if (crash_base <= 0) {
455 		crash_base = memblock_find_in_range(CRASH_ALIGN, CRASH_ADDR_MAX,
456 							crash_size, CRASH_ALIGN);
457 		if (!crash_base) {
458 			pr_warn("crashkernel reservation failed - No suitable area found.\n");
459 			return;
460 		}
461 	} else {
462 		unsigned long long start;
463 
464 		start = memblock_find_in_range(crash_base, crash_base + crash_size,
465 						crash_size, 1);
466 		if (start != crash_base) {
467 			pr_warn("Invalid memory region reserved for crash kernel\n");
468 			return;
469 		}
470 	}
471 
472 	crashk_res.start = crash_base;
473 	crashk_res.end	 = crash_base + crash_size - 1;
474 }
475 
476 static void __init request_crashkernel(struct resource *res)
477 {
478 	int ret;
479 
480 	if (crashk_res.start == crashk_res.end)
481 		return;
482 
483 	ret = request_resource(res, &crashk_res);
484 	if (!ret)
485 		pr_info("Reserving %ldMB of memory at %ldMB for crashkernel\n",
486 			(unsigned long)(resource_size(&crashk_res) >> 20),
487 			(unsigned long)(crashk_res.start  >> 20));
488 }
489 #else /* !defined(CONFIG_KEXEC)		*/
490 static void __init mips_parse_crashkernel(void)
491 {
492 }
493 
494 static void __init request_crashkernel(struct resource *res)
495 {
496 }
497 #endif /* !defined(CONFIG_KEXEC)  */
498 
499 static void __init check_kernel_sections_mem(void)
500 {
501 	phys_addr_t start = PFN_PHYS(PFN_DOWN(__pa_symbol(&_text)));
502 	phys_addr_t size = PFN_PHYS(PFN_UP(__pa_symbol(&_end))) - start;
503 
504 	if (!memblock_is_region_memory(start, size)) {
505 		pr_info("Kernel sections are not in the memory maps\n");
506 		memblock_add(start, size);
507 	}
508 }
509 
510 static void __init bootcmdline_append(const char *s, size_t max)
511 {
512 	if (!s[0] || !max)
513 		return;
514 
515 	if (boot_command_line[0])
516 		strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
517 
518 	strlcat(boot_command_line, s, max);
519 }
520 
521 #ifdef CONFIG_OF_EARLY_FLATTREE
522 
523 static int __init bootcmdline_scan_chosen(unsigned long node, const char *uname,
524 					  int depth, void *data)
525 {
526 	bool *dt_bootargs = data;
527 	const char *p;
528 	int l;
529 
530 	if (depth != 1 || !data ||
531 	    (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
532 		return 0;
533 
534 	p = of_get_flat_dt_prop(node, "bootargs", &l);
535 	if (p != NULL && l > 0) {
536 		bootcmdline_append(p, min(l, COMMAND_LINE_SIZE));
537 		*dt_bootargs = true;
538 	}
539 
540 	return 1;
541 }
542 
543 #endif /* CONFIG_OF_EARLY_FLATTREE */
544 
545 static void __init bootcmdline_init(void)
546 {
547 	bool dt_bootargs = false;
548 
549 	/*
550 	 * If CMDLINE_OVERRIDE is enabled then initializing the command line is
551 	 * trivial - we simply use the built-in command line unconditionally &
552 	 * unmodified.
553 	 */
554 	if (IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
555 		strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
556 		return;
557 	}
558 
559 	/*
560 	 * If the user specified a built-in command line &
561 	 * MIPS_CMDLINE_BUILTIN_EXTEND, then the built-in command line is
562 	 * prepended to arguments from the bootloader or DT so we'll copy them
563 	 * to the start of boot_command_line here. Otherwise, empty
564 	 * boot_command_line to undo anything early_init_dt_scan_chosen() did.
565 	 */
566 	if (IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND))
567 		strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
568 	else
569 		boot_command_line[0] = 0;
570 
571 #ifdef CONFIG_OF_EARLY_FLATTREE
572 	/*
573 	 * If we're configured to take boot arguments from DT, look for those
574 	 * now.
575 	 */
576 	if (IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB) ||
577 	    IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND))
578 		of_scan_flat_dt(bootcmdline_scan_chosen, &dt_bootargs);
579 #endif
580 
581 	/*
582 	 * If we didn't get any arguments from DT (regardless of whether that's
583 	 * because we weren't configured to look for them, or because we looked
584 	 * & found none) then we'll take arguments from the bootloader.
585 	 * plat_mem_setup() should have filled arcs_cmdline with arguments from
586 	 * the bootloader.
587 	 */
588 	if (IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND) || !dt_bootargs)
589 		bootcmdline_append(arcs_cmdline, COMMAND_LINE_SIZE);
590 
591 	/*
592 	 * If the user specified a built-in command line & we didn't already
593 	 * prepend it, we append it to boot_command_line here.
594 	 */
595 	if (IS_ENABLED(CONFIG_CMDLINE_BOOL) &&
596 	    !IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND))
597 		bootcmdline_append(builtin_cmdline, COMMAND_LINE_SIZE);
598 }
599 
600 /*
601  * arch_mem_init - initialize memory management subsystem
602  *
603  *  o plat_mem_setup() detects the memory configuration and will record detected
604  *    memory areas using memblock_add.
605  *
606  * At this stage the memory configuration of the system is known to the
607  * kernel but generic memory management system is still entirely uninitialized.
608  *
609  *  o bootmem_init()
610  *  o sparse_init()
611  *  o paging_init()
612  *  o dma_contiguous_reserve()
613  *
614  * At this stage the bootmem allocator is ready to use.
615  *
616  * NOTE: historically plat_mem_setup did the entire platform initialization.
617  *	 This was rather impractical because it meant plat_mem_setup had to
618  * get away without any kind of memory allocator.  To keep old code from
619  * breaking plat_setup was just renamed to plat_mem_setup and a second platform
620  * initialization hook for anything else was introduced.
621  */
622 static void __init arch_mem_init(char **cmdline_p)
623 {
624 	/* call board setup routine */
625 	plat_mem_setup();
626 	memblock_set_bottom_up(true);
627 
628 	bootcmdline_init();
629 	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
630 	*cmdline_p = command_line;
631 
632 	parse_early_param();
633 
634 	if (usermem)
635 		pr_info("User-defined physical RAM map overwrite\n");
636 
637 	check_kernel_sections_mem();
638 
639 	early_init_fdt_reserve_self();
640 	early_init_fdt_scan_reserved_mem();
641 
642 #ifndef CONFIG_NUMA
643 	memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0);
644 #endif
645 	bootmem_init();
646 
647 	/*
648 	 * Prevent memblock from allocating high memory.
649 	 * This cannot be done before max_low_pfn is detected, so up
650 	 * to this point is possible to only reserve physical memory
651 	 * with memblock_reserve; memblock_alloc* can be used
652 	 * only after this point
653 	 */
654 	memblock_set_current_limit(PFN_PHYS(max_low_pfn));
655 
656 #ifdef CONFIG_PROC_VMCORE
657 	if (setup_elfcorehdr && setup_elfcorehdr_size) {
658 		printk(KERN_INFO "kdump reserved memory at %lx-%lx\n",
659 		       setup_elfcorehdr, setup_elfcorehdr_size);
660 		memblock_reserve(setup_elfcorehdr, setup_elfcorehdr_size);
661 	}
662 #endif
663 
664 	mips_parse_crashkernel();
665 #ifdef CONFIG_KEXEC
666 	if (crashk_res.start != crashk_res.end)
667 		memblock_reserve(crashk_res.start, resource_size(&crashk_res));
668 #endif
669 	device_tree_init();
670 
671 	/*
672 	 * In order to reduce the possibility of kernel panic when failed to
673 	 * get IO TLB memory under CONFIG_SWIOTLB, it is better to allocate
674 	 * low memory as small as possible before plat_swiotlb_setup(), so
675 	 * make sparse_init() using top-down allocation.
676 	 */
677 	memblock_set_bottom_up(false);
678 	sparse_init();
679 	memblock_set_bottom_up(true);
680 
681 	plat_swiotlb_setup();
682 
683 	dma_contiguous_reserve(PFN_PHYS(max_low_pfn));
684 
685 	/* Reserve for hibernation. */
686 	memblock_reserve(__pa_symbol(&__nosave_begin),
687 		__pa_symbol(&__nosave_end) - __pa_symbol(&__nosave_begin));
688 
689 	fdt_init_reserved_mem();
690 
691 	memblock_dump_all();
692 
693 	early_memtest(PFN_PHYS(ARCH_PFN_OFFSET), PFN_PHYS(max_low_pfn));
694 }
695 
696 static void __init resource_init(void)
697 {
698 	phys_addr_t start, end;
699 	u64 i;
700 
701 	if (UNCAC_BASE != IO_BASE)
702 		return;
703 
704 	code_resource.start = __pa_symbol(&_text);
705 	code_resource.end = __pa_symbol(&_etext) - 1;
706 	data_resource.start = __pa_symbol(&_etext);
707 	data_resource.end = __pa_symbol(&_edata) - 1;
708 	bss_resource.start = __pa_symbol(&__bss_start);
709 	bss_resource.end = __pa_symbol(&__bss_stop) - 1;
710 
711 	for_each_mem_range(i, &start, &end) {
712 		struct resource *res;
713 
714 		res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
715 		if (!res)
716 			panic("%s: Failed to allocate %zu bytes\n", __func__,
717 			      sizeof(struct resource));
718 
719 		res->start = start;
720 		/*
721 		 * In memblock, end points to the first byte after the
722 		 * range while in resourses, end points to the last byte in
723 		 * the range.
724 		 */
725 		res->end = end - 1;
726 		res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
727 		res->name = "System RAM";
728 
729 		request_resource(&iomem_resource, res);
730 
731 		/*
732 		 *  We don't know which RAM region contains kernel data,
733 		 *  so we try it repeatedly and let the resource manager
734 		 *  test it.
735 		 */
736 		request_resource(res, &code_resource);
737 		request_resource(res, &data_resource);
738 		request_resource(res, &bss_resource);
739 		request_crashkernel(res);
740 	}
741 }
742 
743 #ifdef CONFIG_SMP
744 static void __init prefill_possible_map(void)
745 {
746 	int i, possible = num_possible_cpus();
747 
748 	if (possible > nr_cpu_ids)
749 		possible = nr_cpu_ids;
750 
751 	for (i = 0; i < possible; i++)
752 		set_cpu_possible(i, true);
753 	for (; i < NR_CPUS; i++)
754 		set_cpu_possible(i, false);
755 
756 	nr_cpu_ids = possible;
757 }
758 #else
759 static inline void prefill_possible_map(void) {}
760 #endif
761 
762 void __init setup_arch(char **cmdline_p)
763 {
764 	cpu_probe();
765 	mips_cm_probe();
766 	prom_init();
767 
768 	setup_early_fdc_console();
769 #ifdef CONFIG_EARLY_PRINTK
770 	setup_early_printk();
771 #endif
772 	cpu_report();
773 	check_bugs_early();
774 
775 #if defined(CONFIG_VT)
776 #if defined(CONFIG_VGA_CONSOLE)
777 	conswitchp = &vga_con;
778 #endif
779 #endif
780 
781 	arch_mem_init(cmdline_p);
782 	dmi_setup();
783 
784 	resource_init();
785 	plat_smp_setup();
786 	prefill_possible_map();
787 
788 	cpu_cache_init();
789 	paging_init();
790 }
791 
792 unsigned long kernelsp[NR_CPUS];
793 unsigned long fw_arg0, fw_arg1, fw_arg2, fw_arg3;
794 
795 #ifdef CONFIG_USE_OF
796 unsigned long fw_passed_dtb;
797 #endif
798 
799 #ifdef CONFIG_DEBUG_FS
800 struct dentry *mips_debugfs_dir;
801 static int __init debugfs_mips(void)
802 {
803 	mips_debugfs_dir = debugfs_create_dir("mips", NULL);
804 	return 0;
805 }
806 arch_initcall(debugfs_mips);
807 #endif
808 
809 #ifdef CONFIG_DMA_MAYBE_COHERENT
810 /* User defined DMA coherency from command line. */
811 enum coherent_io_user_state coherentio = IO_COHERENCE_DEFAULT;
812 EXPORT_SYMBOL_GPL(coherentio);
813 int hw_coherentio;	/* Actual hardware supported DMA coherency setting. */
814 
815 static int __init setcoherentio(char *str)
816 {
817 	coherentio = IO_COHERENCE_ENABLED;
818 	pr_info("Hardware DMA cache coherency (command line)\n");
819 	return 0;
820 }
821 early_param("coherentio", setcoherentio);
822 
823 static int __init setnocoherentio(char *str)
824 {
825 	coherentio = IO_COHERENCE_DISABLED;
826 	pr_info("Software DMA cache coherency (command line)\n");
827 	return 0;
828 }
829 early_param("nocoherentio", setnocoherentio);
830 #endif
831