xref: /netbsd-src/sys/arch/mipsco/mipsco/machdep.c (revision d710132b4b8ce7f7cccaaf660cb16aa16b4077a0)
1 /*	$NetBSD: machdep.c,v 1.38 2003/04/26 11:05:15 ragge Exp $	*/
2 
3 /*
4  * Copyright (c) 1988 University of Utah.
5  * Copyright (c) 1992, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * the Systems Programming Group of the University of Utah Computer
10  * Science Department, The Mach Operating System project at
11  * Carnegie-Mellon University and Ralph Campbell.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  * 3. All advertising materials mentioning features or use of this software
22  *    must display the following acknowledgement:
23  *	This product includes software developed by the University of
24  *	California, Berkeley and its contributors.
25  * 4. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  *
41  *	@(#)machdep.c	8.3 (Berkeley) 1/12/94
42  */
43 
44 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
45 
46 __KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.38 2003/04/26 11:05:15 ragge Exp $");
47 
48 /* from: Utah Hdr: machdep.c 1.63 91/04/24 */
49 
50 #include "opt_ddb.h"
51 #include "opt_kgdb.h"
52 
53 #include <sys/param.h>
54 #include <sys/signalvar.h>
55 #include <sys/kernel.h>
56 #include <sys/proc.h>
57 #include <sys/buf.h>
58 #include <sys/reboot.h>
59 #include <sys/conf.h>
60 #include <sys/file.h>
61 #include <sys/callout.h>
62 #include <sys/malloc.h>
63 #include <sys/mbuf.h>
64 #include <sys/msgbuf.h>
65 #include <sys/ioctl.h>
66 #include <sys/device.h>
67 #include <sys/user.h>
68 #include <sys/exec.h>
69 #include <sys/mount.h>
70 #include <sys/sa.h>
71 #include <sys/syscallargs.h>
72 #include <sys/kcore.h>
73 #include <sys/ksyms.h>
74 
75 #include <uvm/uvm_extern.h>
76 
77 #include <ufs/mfs/mfs_extern.h>		/* mfs_initminiroot() */
78 
79 #include <machine/cpu.h>
80 #include <machine/reg.h>
81 #include <machine/psl.h>
82 #include <machine/pte.h>
83 
84 #ifdef DDB
85 #include <machine/db_machdep.h>
86 #include <ddb/db_extern.h>
87 #endif
88 
89 #include <machine/intr.h>
90 #include <machine/mainboard.h>
91 #include <machine/sysconf.h>
92 #include <machine/autoconf.h>
93 #include <machine/bootinfo.h>
94 #include <machine/prom.h>
95 #include <dev/clock_subr.h>
96 #include <dev/cons.h>
97 
98 #include <sys/boot_flag.h>
99 
100 #include "fs_mfs.h"
101 #include "opt_ddb.h"
102 #include "opt_execfmt.h"
103 
104 #include "zsc.h"			/* XXX */
105 #include "com.h"			/* XXX */
106 #include "ksyms.h"
107 
108 /* the following is used externally (sysctl_hw) */
109 extern char  cpu_model[];
110 
111 /* Our exported CPU info; we can have only one. */
112 struct cpu_info cpu_info_store;
113 
114 /* maps for VM objects */
115 
116 struct vm_map *exec_map = NULL;
117 struct vm_map *mb_map = NULL;
118 struct vm_map *phys_map = NULL;
119 
120 int	physmem;		/* max supported memory, changes to actual */
121 char	*bootinfo = NULL;	/* pointer to bootinfo structure */
122 
123 phys_ram_seg_t mem_clusters[VM_PHYSSEG_MAX];
124 int mem_cluster_cnt;
125 
126 void to_monitor __P((int)) __attribute__((__noreturn__));
127 void prom_halt __P((int)) __attribute__((__noreturn__));
128 
129 #ifdef	KGDB
130 void zs_kgdb_init __P((void));
131 void kgdb_connect __P((int));
132 #endif
133 
134 struct evcnt soft_evcnt[IPL_NSOFT];
135 
136 /*
137  *  Local functions.
138  */
139 int initcpu __P((void));
140 void configure __P((void));
141 
142 void mach_init __P((int, char *[], char*[], u_int, char *));
143 int  memsize_scan __P((caddr_t));
144 
145 #ifdef DEBUG
146 /* stacktrace code violates prototypes to get callee's registers */
147 extern void stacktrace __P((void)); /*XXX*/
148 #endif
149 
150 /*
151  * safepri is a safe priority for sleep to set for a spin-wait
152  * during autoconfiguration or after a panic.  Used as an argument to splx().
153  * XXX disables interrupt 5 to disable mips3 on-chip clock, which also
154  * disables mips1 FPU interrupts.
155  */
156 int	safepri = MIPS3_PSL_LOWIPL;	/* XXX */
157 extern struct user *proc0paddr;
158 
159 /* locore callback-vector setup */
160 extern void mips_vector_init  __P((void));
161 extern void prom_init  __P((void));
162 extern void pizazz_init __P((void));
163 
164 /* platform-specific initialization vector */
165 static void	unimpl_cons_init __P((void));
166 static void	unimpl_iointr __P((unsigned, unsigned, unsigned, unsigned));
167 static int	unimpl_memsize __P((caddr_t));
168 static unsigned	unimpl_clkread __P((void));
169 static void	unimpl_todr __P((struct clock_ymdhms *));
170 static void	unimpl_intr_establish __P((int, int (*)__P((void *)), void *));
171 
172 struct platform platform = {
173 	"iobus not set",
174 	unimpl_cons_init,
175 	unimpl_iointr,
176 	unimpl_memsize,
177 	unimpl_clkread,
178 	unimpl_todr,
179 	unimpl_todr,
180 	unimpl_intr_establish,
181 };
182 
183 struct consdev *cn_tab = NULL;
184 extern struct consdev consdev_prom;
185 extern struct consdev consdev_zs;
186 
187 static void null_cnprobe __P((struct consdev *));
188 static void prom_cninit __P((struct consdev *));
189 static int  prom_cngetc __P((dev_t));
190 static void prom_cnputc __P((dev_t, int));
191 static void null_cnpollc __P((dev_t, int));
192 
193 struct consdev consdev_prom = {
194         null_cnprobe,
195 	prom_cninit,
196 	prom_cngetc,
197 	prom_cnputc,
198         null_cnpollc,
199 };
200 
201 
202 /*
203  * Do all the stuff that locore normally does before calling main().
204  * Process arguments passed to us by the prom monitor.
205  * Return the first page address following the system.
206  */
207 void
208 mach_init(argc, argv, envp, bim, bip)
209 	int    argc;
210 	char   *argv[];
211 	char   *envp[];
212 	u_int  bim;
213 	char   *bip;
214 {
215 	u_long first, last;
216 	caddr_t kernend, v;
217 	vsize_t size;
218 	char *cp;
219 	int i, howto;
220 	extern char edata[], end[];
221 	char *bi_msg;
222 #if NKSYMS || defined(DDB) || defined(LKM)
223 	int nsym = 0;
224 	caddr_t ssym = 0;
225 	caddr_t esym = 0;
226 	struct btinfo_symtab *bi_syms;
227 #endif
228 
229 
230 	/* Check for valid bootinfo passed from bootstrap */
231 	if (bim == BOOTINFO_MAGIC) {
232 		struct btinfo_magic *bi_magic;
233 
234 		bootinfo = (char *)BOOTINFO_ADDR; /* XXX */
235 		bi_magic = lookup_bootinfo(BTINFO_MAGIC);
236 		if (bi_magic == NULL || bi_magic->magic != BOOTINFO_MAGIC)
237 			bi_msg = "invalid bootinfo structure.\n";
238 		else
239 			bi_msg = NULL;
240 	} else
241 		bi_msg = "invalid bootinfo (standalone boot?)\n";
242 
243 	/* clear the BSS segment */
244 	kernend = (caddr_t)mips_round_page(end);
245 	memset(edata, 0, end - edata);
246 
247 #if NKSYMS || defined(DDB) || defined(LKM)
248 	bi_syms = lookup_bootinfo(BTINFO_SYMTAB);
249 
250 	/* Load sysmbol table if present */
251 	if (bi_syms != NULL) {
252 		nsym = bi_syms->nsym;
253 		ssym = (caddr_t)bi_syms->ssym;
254 		esym = (caddr_t)bi_syms->esym;
255 		kernend = (caddr_t)mips_round_page(esym);
256 	}
257 #endif
258 
259 	prom_init();
260 	consinit();
261 
262 	if (bi_msg != NULL)
263 		printf(bi_msg);
264 
265 	/*
266 	 * Set the VM page size.
267 	 */
268 	uvm_setpagesize();
269 
270 	/* Find out how much memory is available. */
271 	physmem = memsize_scan(kernend);
272 
273 	/*
274 	 * Now that we know how much memory we have, initialize the
275 	 * mem cluster array.
276 	 */
277 	mem_clusters[0].start = 0;		/* XXX is this correct? */
278 	mem_clusters[0].size  = ctob(physmem);
279 	mem_cluster_cnt = 1;
280 
281 	/*
282 	 * Copy exception-dispatch code down to exception vector.
283 	 * Initialize locore-function vector.
284 	 * Clear out the I and D caches.
285 	 */
286 	mips_vector_init();
287 
288 	/* Look at argv[0] and compute bootdev */
289 	makebootdev(argv[0]);
290 
291 	/*
292 	 * Look at arguments passed to us and compute boothowto.
293 	 */
294 	boothowto = RB_AUTOBOOT;
295 	for (i = 1; i < argc; i++) {
296 		for (cp = argv[i]; *cp; cp++) {
297 			/* Ignore superfluous '-', if there is one */
298 			if (*cp == '-')
299 				continue;
300 
301 			howto = 0;
302 			BOOT_FLAG(*cp, howto);
303 			if (! howto)
304 				printf("bootflag '%c' not recognised\n", *cp);
305 			else
306 				boothowto |= howto;
307 		}
308 	}
309 
310 
311 #if NKSYMS || defined(DDB) || defined(LKM)
312 	/* init symbols if present */
313 	if (esym)
314 		ksyms_init(esym - ssym, ssym, esym);
315 #endif
316 #ifdef DDB
317 	if (boothowto & RB_KDB)
318 		Debugger();
319 #endif
320 #ifdef KGDB
321 	zs_kgdb_init();			/* XXX */
322 	if (boothowto & RB_KDB)
323 		kgdb_connect(0);
324 #endif
325 
326 #ifdef MFS
327 	/*
328 	 * Check to see if a mini-root was loaded into memory. It resides
329 	 * at the start of the next page just after the end of BSS.
330 	 */
331 	if (boothowto & RB_MINIROOT)
332 		kernend += round_page(mfs_initminiroot(kernend));
333 #endif
334 
335 	/*
336 	 * Load the rest of the available pages into the VM system.
337 	 */
338 	first = round_page(MIPS_KSEG0_TO_PHYS(kernend));
339 	last = mem_clusters[0].start + mem_clusters[0].size;
340 	uvm_page_physload(atop(first), atop(last), atop(first), atop(last),
341 	    VM_FREELIST_DEFAULT);
342 
343 	/*
344 	 * Initialize error message buffer (at end of core).
345 	 */
346 	mips_init_msgbuf();
347 
348 	/*
349 	 * Compute the size of system data structures.  pmap_bootstrap()
350 	 * needs some of this information.
351 	 */
352 	size = (vsize_t)allocsys(NULL, NULL);
353 
354 	/*
355 	 * Initialize the virtual memory system.
356 	 */
357 	pmap_bootstrap();
358 
359 	/*
360 	 * Allocate space for proc0's USPACE.
361 	 */
362 	v = (caddr_t)uvm_pageboot_alloc(USPACE);
363 	lwp0.l_addr = proc0paddr = (struct user *)v;
364 	lwp0.l_md.md_regs = (struct frame *)(v + USPACE) - 1;
365 	curpcb = &lwp0.l_addr->u_pcb;
366 	curpcb->pcb_context[11] = MIPS_INT_MASK | MIPS_SR_INT_IE; /* SR */
367 
368 	/*
369 	 * Allocate space for system data structures.  These data structures
370 	 * are allocated here instead of cpu_startup() because physical
371 	 * memory is directly addressable.  We don't have to map these into
372 	 * virtual address space.
373 	 */
374 	v = (caddr_t)uvm_pageboot_alloc(size);
375 	if ((allocsys(v, NULL) - v) != size)
376 		panic("mach_init: table size inconsistency");
377 	/*
378 	 * Set up interrupt handling and I/O addresses.
379 	 */
380 
381 	pizazz_init();
382 }
383 
384 
385 
386 /*
387  * cpu_startup: allocate memory for variable-sized tables,
388  * initialize cpu, and do autoconfiguration.
389  */
390 void
391 cpu_startup()
392 {
393 	u_int i, base, residual;
394 	vaddr_t minaddr, maxaddr;
395 	vsize_t size;
396 	char pbuf[9];
397 #ifdef DEBUG
398 	extern int pmapdebug;
399 	int opmapdebug = pmapdebug;
400 
401 	pmapdebug = 0;
402 #endif
403 
404 	/*
405 	 * Good {morning,afternoon,evening,night}.
406 	 */
407 	printf(version);
408 	printf("%s\n", cpu_model);
409 	format_bytes(pbuf, sizeof(pbuf), ctob(physmem));
410 	printf("total memory = %s\n", pbuf);
411 
412 	/*
413 	 * Allocate virtual address space for file I/O buffers.
414 	 * Note they are different than the array of headers, 'buf',
415 	 * and usually occupy more virtual memory than physical.
416 	 */
417 	size = MAXBSIZE * nbuf;
418 	if (uvm_map(kernel_map, (vaddr_t *)&buffers, round_page(size),
419 		    NULL, UVM_UNKNOWN_OFFSET, 0,
420 		    UVM_MAPFLAG(UVM_PROT_NONE, UVM_PROT_NONE, UVM_INH_NONE,
421 				UVM_ADV_NORMAL, 0)) != 0)
422 		panic("startup: cannot allocate VM for buffers");
423 	minaddr = (vaddr_t)buffers;
424 	base = bufpages / nbuf;
425 	residual = bufpages % nbuf;
426 	for (i = 0; i < nbuf; i++) {
427 		vsize_t curbufsize;
428 		vaddr_t curbuf;
429 		struct vm_page *pg;
430 
431 		/*
432 		 * Each buffer has MAXBSIZE bytes of VM space allocated.  Of
433 		 * that MAXBSIZE space, we allocate and map (base+1) pages
434 		 * for the first "residual" buffers, and then we allocate
435 		 * "base" pages for the rest.
436 		 */
437 		curbuf = (vaddr_t) buffers + (i * MAXBSIZE);
438 		curbufsize = PAGE_SIZE * ((i < residual) ? (base+1) : base);
439 
440 		while (curbufsize) {
441 			pg = uvm_pagealloc(NULL, 0, NULL, 0);
442 			if (pg == NULL)
443 				panic("cpu_startup: not enough memory for "
444 				    "buffer cache");
445 			pmap_kenter_pa(curbuf, VM_PAGE_TO_PHYS(pg),
446 				       VM_PROT_READ|VM_PROT_WRITE);
447 			curbuf += PAGE_SIZE;
448 			curbufsize -= PAGE_SIZE;
449 		}
450 	}
451 	pmap_update(pmap_kernel());
452 
453 	/*
454 	 * Allocate a submap for exec arguments.  This map effectively
455 	 * limits the number of processes exec'ing at any time.
456 	 */
457 	exec_map = uvm_km_suballoc(kernel_map, &minaddr, &maxaddr,
458 				   16 * NCARGS, TRUE, FALSE, NULL);
459 	/*
460 	 * Allocate a submap for physio
461 	 */
462 	phys_map = uvm_km_suballoc(kernel_map, &minaddr, &maxaddr,
463 				   VM_PHYS_SIZE, TRUE, FALSE, NULL);
464 
465 	/*
466 	 * No need to allocate an mbuf cluster submap.  Mbuf clusters
467 	 * are allocated via the pool allocator, and we use KSEG to
468 	 * map those pages.
469 	 */
470 
471 #ifdef DEBUG
472 	pmapdebug = opmapdebug;
473 #endif
474 	format_bytes(pbuf, sizeof(pbuf), ptoa(uvmexp.free));
475 	printf("avail memory = %s\n", pbuf);
476 	format_bytes(pbuf, sizeof(pbuf), bufpages * PAGE_SIZE);
477 	printf("using %u buffers containing %s of memory\n", nbuf, pbuf);
478 
479 	/*
480 	 * Set up buffers, so they can be used to read disk labels.
481 	 */
482 	bufinit();
483 }
484 
485 /*
486  * Look up information in bootinfo of boot loader.
487  */
488 void *
489 lookup_bootinfo(type)
490 	int type;
491 {
492 	struct btinfo_common *bt;
493 	char *help = bootinfo;
494 
495 	/* Check for a bootinfo record first. */
496 	if (help == NULL)
497 		return (NULL);
498 
499 	do {
500 		bt = (struct btinfo_common *)help;
501 		if (bt->type == type)
502 			return ((void *)help);
503 		help += bt->next;
504 	} while (bt->next != 0 &&
505 		(size_t)help < (size_t)bootinfo + BOOTINFO_SIZE);
506 
507 	return (NULL);
508 }
509 
510 int	waittime = -1;
511 
512 /*
513  * call PROM to halt or reboot.
514  */
515 void
516 prom_halt(howto)
517 	int howto;
518 {
519 	if (howto & RB_HALT)
520 		MIPS_PROM(reinit)();
521 	MIPS_PROM(reboot)();
522 	/* NOTREACHED */
523 }
524 
525 void
526 cpu_reboot(howto, bootstr)
527 	volatile int howto;
528 	char *bootstr;
529 {
530 	/* take a snap shot before clobbering any registers */
531 	if (curlwp)
532 		savectx((struct user *)curpcb);
533 
534 #ifdef DEBUG
535 	if (panicstr)
536 		stacktrace();
537 #endif
538 
539 	/* If system is cold, just halt. */
540 	if (cold) {
541 		howto |= RB_HALT;
542 		goto haltsys;
543 	}
544 
545 	/* If "always halt" was specified as a boot flag, obey. */
546 	if ((boothowto & RB_HALT) != 0)
547 		howto |= RB_HALT;
548 
549 	boothowto = howto;
550 	if ((howto & RB_NOSYNC) == 0 && waittime < 0) {
551 		/*
552 		 * Synchronize the disks....
553 		 */
554 		waittime = 0;
555 		vfs_shutdown();
556 
557 		/*
558 		 * If we've been adjusting the clock, the todr
559 		 * will be out of synch; adjust it now.
560 		 */
561 		resettodr();
562 	}
563 
564 	/* Disable interrupts. */
565 	splhigh();
566 
567 	/* If rebooting and a dump is requested do it. */
568 #if 0
569 	if ((howto & (RB_DUMP | RB_HALT)) == RB_DUMP)
570 #else
571 	if (howto & RB_DUMP)
572 #endif
573 		dumpsys();
574 
575 haltsys:
576 
577 	/* run any shutdown hooks */
578 	doshutdownhooks();
579 
580 	if ((howto & RB_POWERDOWN) == RB_POWERDOWN)
581 		prom_halt(0x80);	/* rom monitor RB_PWOFF */
582 
583 	/* Finally, halt/reboot the system. */
584 	printf("%s\n\n", howto & RB_HALT ? "halted." : "rebooting...");
585 	prom_halt(howto & RB_HALT);
586 	/*NOTREACHED*/
587 }
588 
589 /*
590  * Return the best possible estimate of the time in the timeval
591  * to which tvp points.  Unfortunately, we can't read the hardware registers.
592  * We guarantee that the time will be greater than the value obtained by a
593  * previous call.
594  */
595 void
596 microtime(tvp)
597 	register struct timeval *tvp;
598 {
599 	static struct timeval lasttime;
600 	int s = splclock();
601 
602 	*tvp = time;
603 
604 	tvp->tv_usec += (*platform.clkread)();
605 
606 	while (tvp->tv_usec >= 1000000) {
607 		tvp->tv_usec -= 1000000;
608 		tvp->tv_sec++;
609 	}
610 
611 	if (tvp->tv_sec == lasttime.tv_sec &&
612 	    tvp->tv_usec <= lasttime.tv_usec &&
613 	    (tvp->tv_usec = lasttime.tv_usec + 1) > 1000000) {
614 		tvp->tv_sec++;
615 		tvp->tv_usec -= 1000000;
616 	}
617 	lasttime = *tvp;
618 	splx(s);
619 }
620 
621 int
622 initcpu()
623 {
624 	spl0();		/* safe to turn interrupts on now */
625 	return 0;
626 }
627 
628 static void
629 unimpl_cons_init()
630 {
631 
632 	panic("sysconf.init didn't set cons_init");
633 }
634 
635 static void
636 unimpl_iointr(mask, pc, statusreg, causereg)
637 	u_int mask;
638 	u_int pc;
639 	u_int statusreg;
640 	u_int causereg;
641 {
642 
643 	panic("sysconf.init didn't set intr");
644 }
645 
646 static int
647 unimpl_memsize(first)
648 caddr_t first;
649 {
650 
651 	panic("sysconf.init didn't set memsize");
652 }
653 
654 static unsigned
655 unimpl_clkread()
656 {
657 	return 0;	/* No microtime available */
658 }
659 
660 static void
661 unimpl_todr(dt)
662 	struct clock_ymdhms *dt;
663 {
664 	panic("sysconf.init didn't init TOD");
665 }
666 
667 void
668 unimpl_intr_establish(level, func, arg)
669 	int level;
670 	int (*func) __P((void *));
671 	void *arg;
672 {
673 	panic("sysconf.init didn't init intr_establish");
674 }
675 
676 void
677 delay(n)
678 	int n;
679 {
680 	DELAY(n);
681 }
682 
683 /*
684  * Find out how much memory is available by testing memory.
685  * Be careful to save and restore the original contents for msgbuf.
686  */
687 int
688 memsize_scan(first)
689 	caddr_t first;
690 {
691 	volatile int *vp, *vp0;
692 	int mem, tmp, tmp0;
693 
694 #define PATTERN1 0xa5a5a5a5
695 #define	PATTERN2 ~PATTERN1
696 
697 	/*
698 	 * Non destructive scan of memory to determine the size
699 	 * Use the first page to test for memory aliases.  This
700 	 * also has the side effect of flushing the bus alignment
701 	 * buffer
702 	 */
703 	mem = btoc((paddr_t)first - MIPS_KSEG0_START);
704 	vp = (int *)MIPS_PHYS_TO_KSEG1(mem << PGSHIFT);
705 	vp0 = (int *)MIPS_PHYS_TO_KSEG1(0); /* Start of physical memory */
706 	tmp0 = *vp0;
707 	while (vp < (int *)MIPS_MAX_MEM_ADDR) {
708 		tmp = *vp;
709 		*vp  = PATTERN1;
710 		*vp0 = PATTERN2;
711 		wbflush();
712 		if (*vp != PATTERN1)
713 			break;
714 		*vp  = PATTERN2;
715 		*vp0 = PATTERN1;
716 		wbflush();
717 		if (*vp != PATTERN2)
718 			break;
719 		*vp = tmp;
720 		vp += PAGE_SIZE/sizeof(int);
721 		mem++;
722 	}
723 	*vp0 = tmp0;
724 	return mem;
725 }
726 
727 /*
728  * Console initialization: called early on from main,
729  * before vm init or startup.  Do enough configuration
730  * to choose and initialize a console.
731  */
732 
733 static void
734 null_cnprobe(cn)
735      struct consdev *cn;
736 {
737 }
738 
739 static void
740 prom_cninit(cn)
741 	struct consdev *cn;
742 {
743 	extern const struct cdevsw cons_cdevsw;
744 
745 	cn->cn_dev = makedev(cdevsw_lookup_major(&cons_cdevsw), 0);
746 	cn->cn_pri = CN_REMOTE;
747 }
748 
749 static int
750 prom_cngetc(dev)
751 	dev_t dev;
752 {
753 	return MIPS_PROM(getchar)();
754 }
755 
756 static void
757 prom_cnputc(dev, c)
758 	dev_t dev;
759 	int c;
760 {
761 	MIPS_PROM(putchar)(c);
762 }
763 
764 static void
765 null_cnpollc(dev, on)
766 	dev_t dev;
767 	int on;
768 {
769 }
770 
771 void
772 consinit()
773 {
774 	int zs_unit;
775 
776 	zs_unit = 0;
777 	cn_tab = &consdev_zs;
778 
779 	(*cn_tab->cn_init)(cn_tab);
780 }
781