xref: /linux/arch/powerpc/kernel/rtas.c (revision d8327c784b51b57dac2c26cfad87dce0d68dfd98)
1 /*
2  *
3  * Procedures for interfacing to the RTAS on CHRP machines.
4  *
5  * Peter Bergner, IBM	March 2001.
6  * Copyright (C) 2001 IBM.
7  *
8  *      This program is free software; you can redistribute it and/or
9  *      modify it under the terms of the GNU General Public License
10  *      as published by the Free Software Foundation; either version
11  *      2 of the License, or (at your option) any later version.
12  */
13 
14 #include <stdarg.h>
15 #include <linux/kernel.h>
16 #include <linux/types.h>
17 #include <linux/spinlock.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/capability.h>
21 #include <linux/delay.h>
22 
23 #include <asm/prom.h>
24 #include <asm/rtas.h>
25 #include <asm/hvcall.h>
26 #include <asm/semaphore.h>
27 #include <asm/machdep.h>
28 #include <asm/page.h>
29 #include <asm/param.h>
30 #include <asm/system.h>
31 #include <asm/delay.h>
32 #include <asm/uaccess.h>
33 #include <asm/lmb.h>
34 #include <asm/udbg.h>
35 
36 struct rtas_t rtas = {
37 	.lock = SPIN_LOCK_UNLOCKED
38 };
39 
40 struct rtas_suspend_me_data {
41 	long waiting;
42 	struct rtas_args *args;
43 };
44 
45 EXPORT_SYMBOL(rtas);
46 
47 DEFINE_SPINLOCK(rtas_data_buf_lock);
48 char rtas_data_buf[RTAS_DATA_BUF_SIZE] __cacheline_aligned;
49 unsigned long rtas_rmo_buf;
50 
51 /*
52  * If non-NULL, this gets called when the kernel terminates.
53  * This is done like this so rtas_flash can be a module.
54  */
55 void (*rtas_flash_term_hook)(int);
56 EXPORT_SYMBOL(rtas_flash_term_hook);
57 
58 /*
59  * call_rtas_display_status and call_rtas_display_status_delay
60  * are designed only for very early low-level debugging, which
61  * is why the token is hard-coded to 10.
62  */
63 static void call_rtas_display_status(char c)
64 {
65 	struct rtas_args *args = &rtas.args;
66 	unsigned long s;
67 
68 	if (!rtas.base)
69 		return;
70 	spin_lock_irqsave(&rtas.lock, s);
71 
72 	args->token = 10;
73 	args->nargs = 1;
74 	args->nret  = 1;
75 	args->rets  = (rtas_arg_t *)&(args->args[1]);
76 	args->args[0] = (unsigned char)c;
77 
78 	enter_rtas(__pa(args));
79 
80 	spin_unlock_irqrestore(&rtas.lock, s);
81 }
82 
83 static void call_rtas_display_status_delay(char c)
84 {
85 	static int pending_newline = 0;  /* did last write end with unprinted newline? */
86 	static int width = 16;
87 
88 	if (c == '\n') {
89 		while (width-- > 0)
90 			call_rtas_display_status(' ');
91 		width = 16;
92 		mdelay(500);
93 		pending_newline = 1;
94 	} else {
95 		if (pending_newline) {
96 			call_rtas_display_status('\r');
97 			call_rtas_display_status('\n');
98 		}
99 		pending_newline = 0;
100 		if (width--) {
101 			call_rtas_display_status(c);
102 			udelay(10000);
103 		}
104 	}
105 }
106 
107 void __init udbg_init_rtas(void)
108 {
109 	udbg_putc = call_rtas_display_status_delay;
110 }
111 
112 void rtas_progress(char *s, unsigned short hex)
113 {
114 	struct device_node *root;
115 	int width, *p;
116 	char *os;
117 	static int display_character, set_indicator;
118 	static int display_width, display_lines, *row_width, form_feed;
119 	static DEFINE_SPINLOCK(progress_lock);
120 	static int current_line;
121 	static int pending_newline = 0;  /* did last write end with unprinted newline? */
122 
123 	if (!rtas.base)
124 		return;
125 
126 	if (display_width == 0) {
127 		display_width = 0x10;
128 		if ((root = find_path_device("/rtas"))) {
129 			if ((p = (unsigned int *)get_property(root,
130 					"ibm,display-line-length", NULL)))
131 				display_width = *p;
132 			if ((p = (unsigned int *)get_property(root,
133 					"ibm,form-feed", NULL)))
134 				form_feed = *p;
135 			if ((p = (unsigned int *)get_property(root,
136 					"ibm,display-number-of-lines", NULL)))
137 				display_lines = *p;
138 			row_width = (unsigned int *)get_property(root,
139 					"ibm,display-truncation-length", NULL);
140 		}
141 		display_character = rtas_token("display-character");
142 		set_indicator = rtas_token("set-indicator");
143 	}
144 
145 	if (display_character == RTAS_UNKNOWN_SERVICE) {
146 		/* use hex display if available */
147 		if (set_indicator != RTAS_UNKNOWN_SERVICE)
148 			rtas_call(set_indicator, 3, 1, NULL, 6, 0, hex);
149 		return;
150 	}
151 
152 	spin_lock(&progress_lock);
153 
154 	/*
155 	 * Last write ended with newline, but we didn't print it since
156 	 * it would just clear the bottom line of output. Print it now
157 	 * instead.
158 	 *
159 	 * If no newline is pending and form feed is supported, clear the
160 	 * display with a form feed; otherwise, print a CR to start output
161 	 * at the beginning of the line.
162 	 */
163 	if (pending_newline) {
164 		rtas_call(display_character, 1, 1, NULL, '\r');
165 		rtas_call(display_character, 1, 1, NULL, '\n');
166 		pending_newline = 0;
167 	} else {
168 		current_line = 0;
169 		if (form_feed)
170 			rtas_call(display_character, 1, 1, NULL,
171 				  (char)form_feed);
172 		else
173 			rtas_call(display_character, 1, 1, NULL, '\r');
174 	}
175 
176 	if (row_width)
177 		width = row_width[current_line];
178 	else
179 		width = display_width;
180 	os = s;
181 	while (*os) {
182 		if (*os == '\n' || *os == '\r') {
183 			/* If newline is the last character, save it
184 			 * until next call to avoid bumping up the
185 			 * display output.
186 			 */
187 			if (*os == '\n' && !os[1]) {
188 				pending_newline = 1;
189 				current_line++;
190 				if (current_line > display_lines-1)
191 					current_line = display_lines-1;
192 				spin_unlock(&progress_lock);
193 				return;
194 			}
195 
196 			/* RTAS wants CR-LF, not just LF */
197 
198 			if (*os == '\n') {
199 				rtas_call(display_character, 1, 1, NULL, '\r');
200 				rtas_call(display_character, 1, 1, NULL, '\n');
201 			} else {
202 				/* CR might be used to re-draw a line, so we'll
203 				 * leave it alone and not add LF.
204 				 */
205 				rtas_call(display_character, 1, 1, NULL, *os);
206 			}
207 
208 			if (row_width)
209 				width = row_width[current_line];
210 			else
211 				width = display_width;
212 		} else {
213 			width--;
214 			rtas_call(display_character, 1, 1, NULL, *os);
215 		}
216 
217 		os++;
218 
219 		/* if we overwrite the screen length */
220 		if (width <= 0)
221 			while ((*os != 0) && (*os != '\n') && (*os != '\r'))
222 				os++;
223 	}
224 
225 	spin_unlock(&progress_lock);
226 }
227 EXPORT_SYMBOL(rtas_progress);		/* needed by rtas_flash module */
228 
229 int rtas_token(const char *service)
230 {
231 	int *tokp;
232 	if (rtas.dev == NULL)
233 		return RTAS_UNKNOWN_SERVICE;
234 	tokp = (int *) get_property(rtas.dev, service, NULL);
235 	return tokp ? *tokp : RTAS_UNKNOWN_SERVICE;
236 }
237 
238 #ifdef CONFIG_RTAS_ERROR_LOGGING
239 /*
240  * Return the firmware-specified size of the error log buffer
241  *  for all rtas calls that require an error buffer argument.
242  *  This includes 'check-exception' and 'rtas-last-error'.
243  */
244 int rtas_get_error_log_max(void)
245 {
246 	static int rtas_error_log_max;
247 	if (rtas_error_log_max)
248 		return rtas_error_log_max;
249 
250 	rtas_error_log_max = rtas_token ("rtas-error-log-max");
251 	if ((rtas_error_log_max == RTAS_UNKNOWN_SERVICE) ||
252 	    (rtas_error_log_max > RTAS_ERROR_LOG_MAX)) {
253 		printk (KERN_WARNING "RTAS: bad log buffer size %d\n",
254 			rtas_error_log_max);
255 		rtas_error_log_max = RTAS_ERROR_LOG_MAX;
256 	}
257 	return rtas_error_log_max;
258 }
259 EXPORT_SYMBOL(rtas_get_error_log_max);
260 
261 
262 char rtas_err_buf[RTAS_ERROR_LOG_MAX];
263 int rtas_last_error_token;
264 
265 /** Return a copy of the detailed error text associated with the
266  *  most recent failed call to rtas.  Because the error text
267  *  might go stale if there are any other intervening rtas calls,
268  *  this routine must be called atomically with whatever produced
269  *  the error (i.e. with rtas.lock still held from the previous call).
270  */
271 static char *__fetch_rtas_last_error(char *altbuf)
272 {
273 	struct rtas_args err_args, save_args;
274 	u32 bufsz;
275 	char *buf = NULL;
276 
277 	if (rtas_last_error_token == -1)
278 		return NULL;
279 
280 	bufsz = rtas_get_error_log_max();
281 
282 	err_args.token = rtas_last_error_token;
283 	err_args.nargs = 2;
284 	err_args.nret = 1;
285 	err_args.args[0] = (rtas_arg_t)__pa(rtas_err_buf);
286 	err_args.args[1] = bufsz;
287 	err_args.args[2] = 0;
288 
289 	save_args = rtas.args;
290 	rtas.args = err_args;
291 
292 	enter_rtas(__pa(&rtas.args));
293 
294 	err_args = rtas.args;
295 	rtas.args = save_args;
296 
297 	/* Log the error in the unlikely case that there was one. */
298 	if (unlikely(err_args.args[2] == 0)) {
299 		if (altbuf) {
300 			buf = altbuf;
301 		} else {
302 			buf = rtas_err_buf;
303 			if (mem_init_done)
304 				buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC);
305 		}
306 		if (buf)
307 			memcpy(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX);
308 	}
309 
310 	return buf;
311 }
312 
313 #define get_errorlog_buffer()	kmalloc(RTAS_ERROR_LOG_MAX, GFP_KERNEL)
314 
315 #else /* CONFIG_RTAS_ERROR_LOGGING */
316 #define __fetch_rtas_last_error(x)	NULL
317 #define get_errorlog_buffer()		NULL
318 #endif
319 
320 int rtas_call(int token, int nargs, int nret, int *outputs, ...)
321 {
322 	va_list list;
323 	int i;
324 	unsigned long s;
325 	struct rtas_args *rtas_args;
326 	char *buff_copy = NULL;
327 	int ret;
328 
329 	if (token == RTAS_UNKNOWN_SERVICE)
330 		return -1;
331 
332 	/* Gotta do something different here, use global lock for now... */
333 	spin_lock_irqsave(&rtas.lock, s);
334 	rtas_args = &rtas.args;
335 
336 	rtas_args->token = token;
337 	rtas_args->nargs = nargs;
338 	rtas_args->nret  = nret;
339 	rtas_args->rets  = (rtas_arg_t *)&(rtas_args->args[nargs]);
340 	va_start(list, outputs);
341 	for (i = 0; i < nargs; ++i)
342 		rtas_args->args[i] = va_arg(list, rtas_arg_t);
343 	va_end(list);
344 
345 	for (i = 0; i < nret; ++i)
346 		rtas_args->rets[i] = 0;
347 
348 	enter_rtas(__pa(rtas_args));
349 
350 	/* A -1 return code indicates that the last command couldn't
351 	   be completed due to a hardware error. */
352 	if (rtas_args->rets[0] == -1)
353 		buff_copy = __fetch_rtas_last_error(NULL);
354 
355 	if (nret > 1 && outputs != NULL)
356 		for (i = 0; i < nret-1; ++i)
357 			outputs[i] = rtas_args->rets[i+1];
358 	ret = (nret > 0)? rtas_args->rets[0]: 0;
359 
360 	/* Gotta do something different here, use global lock for now... */
361 	spin_unlock_irqrestore(&rtas.lock, s);
362 
363 	if (buff_copy) {
364 		log_error(buff_copy, ERR_TYPE_RTAS_LOG, 0);
365 		if (mem_init_done)
366 			kfree(buff_copy);
367 	}
368 	return ret;
369 }
370 
371 /* Given an RTAS status code of 990n compute the hinted delay of 10^n
372  * (last digit) milliseconds.  For now we bound at n=5 (100 sec).
373  */
374 unsigned int rtas_extended_busy_delay_time(int status)
375 {
376 	int order = status - 9900;
377 	unsigned long ms;
378 
379 	if (order < 0)
380 		order = 0;	/* RTC depends on this for -2 clock busy */
381 	else if (order > 5)
382 		order = 5;	/* bound */
383 
384 	/* Use microseconds for reasonable accuracy */
385 	for (ms = 1; order > 0; order--)
386 		ms *= 10;
387 
388 	return ms;
389 }
390 
391 int rtas_error_rc(int rtas_rc)
392 {
393 	int rc;
394 
395 	switch (rtas_rc) {
396 		case -1: 		/* Hardware Error */
397 			rc = -EIO;
398 			break;
399 		case -3:		/* Bad indicator/domain/etc */
400 			rc = -EINVAL;
401 			break;
402 		case -9000:		/* Isolation error */
403 			rc = -EFAULT;
404 			break;
405 		case -9001:		/* Outstanding TCE/PTE */
406 			rc = -EEXIST;
407 			break;
408 		case -9002:		/* No usable slot */
409 			rc = -ENODEV;
410 			break;
411 		default:
412 			printk(KERN_ERR "%s: unexpected RTAS error %d\n",
413 					__FUNCTION__, rtas_rc);
414 			rc = -ERANGE;
415 			break;
416 	}
417 	return rc;
418 }
419 
420 int rtas_get_power_level(int powerdomain, int *level)
421 {
422 	int token = rtas_token("get-power-level");
423 	int rc;
424 
425 	if (token == RTAS_UNKNOWN_SERVICE)
426 		return -ENOENT;
427 
428 	while ((rc = rtas_call(token, 1, 2, level, powerdomain)) == RTAS_BUSY)
429 		udelay(1);
430 
431 	if (rc < 0)
432 		return rtas_error_rc(rc);
433 	return rc;
434 }
435 
436 int rtas_set_power_level(int powerdomain, int level, int *setlevel)
437 {
438 	int token = rtas_token("set-power-level");
439 	unsigned int wait_time;
440 	int rc;
441 
442 	if (token == RTAS_UNKNOWN_SERVICE)
443 		return -ENOENT;
444 
445 	while (1) {
446 		rc = rtas_call(token, 2, 2, setlevel, powerdomain, level);
447 		if (rc == RTAS_BUSY)
448 			udelay(1);
449 		else if (rtas_is_extended_busy(rc)) {
450 			wait_time = rtas_extended_busy_delay_time(rc);
451 			udelay(wait_time * 1000);
452 		} else
453 			break;
454 	}
455 
456 	if (rc < 0)
457 		return rtas_error_rc(rc);
458 	return rc;
459 }
460 
461 int rtas_get_sensor(int sensor, int index, int *state)
462 {
463 	int token = rtas_token("get-sensor-state");
464 	unsigned int wait_time;
465 	int rc;
466 
467 	if (token == RTAS_UNKNOWN_SERVICE)
468 		return -ENOENT;
469 
470 	while (1) {
471 		rc = rtas_call(token, 2, 2, state, sensor, index);
472 		if (rc == RTAS_BUSY)
473 			udelay(1);
474 		else if (rtas_is_extended_busy(rc)) {
475 			wait_time = rtas_extended_busy_delay_time(rc);
476 			udelay(wait_time * 1000);
477 		} else
478 			break;
479 	}
480 
481 	if (rc < 0)
482 		return rtas_error_rc(rc);
483 	return rc;
484 }
485 
486 int rtas_set_indicator(int indicator, int index, int new_value)
487 {
488 	int token = rtas_token("set-indicator");
489 	unsigned int wait_time;
490 	int rc;
491 
492 	if (token == RTAS_UNKNOWN_SERVICE)
493 		return -ENOENT;
494 
495 	while (1) {
496 		rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
497 		if (rc == RTAS_BUSY)
498 			udelay(1);
499 		else if (rtas_is_extended_busy(rc)) {
500 			wait_time = rtas_extended_busy_delay_time(rc);
501 			udelay(wait_time * 1000);
502 		}
503 		else
504 			break;
505 	}
506 
507 	if (rc < 0)
508 		return rtas_error_rc(rc);
509 	return rc;
510 }
511 
512 void rtas_restart(char *cmd)
513 {
514 	if (rtas_flash_term_hook)
515 		rtas_flash_term_hook(SYS_RESTART);
516 	printk("RTAS system-reboot returned %d\n",
517 	       rtas_call(rtas_token("system-reboot"), 0, 1, NULL));
518 	for (;;);
519 }
520 
521 void rtas_power_off(void)
522 {
523 	if (rtas_flash_term_hook)
524 		rtas_flash_term_hook(SYS_POWER_OFF);
525 	/* allow power on only with power button press */
526 	printk("RTAS power-off returned %d\n",
527 	       rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1));
528 	for (;;);
529 }
530 
531 void rtas_halt(void)
532 {
533 	if (rtas_flash_term_hook)
534 		rtas_flash_term_hook(SYS_HALT);
535 	/* allow power on only with power button press */
536 	printk("RTAS power-off returned %d\n",
537 	       rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1));
538 	for (;;);
539 }
540 
541 /* Must be in the RMO region, so we place it here */
542 static char rtas_os_term_buf[2048];
543 
544 void rtas_os_term(char *str)
545 {
546 	int status;
547 
548 	if (RTAS_UNKNOWN_SERVICE == rtas_token("ibm,os-term"))
549 		return;
550 
551 	snprintf(rtas_os_term_buf, 2048, "OS panic: %s", str);
552 
553 	do {
554 		status = rtas_call(rtas_token("ibm,os-term"), 1, 1, NULL,
555 				   __pa(rtas_os_term_buf));
556 
557 		if (status == RTAS_BUSY)
558 			udelay(1);
559 		else if (status != 0)
560 			printk(KERN_EMERG "ibm,os-term call failed %d\n",
561 			       status);
562 	} while (status == RTAS_BUSY);
563 }
564 
565 static int ibm_suspend_me_token = RTAS_UNKNOWN_SERVICE;
566 #ifdef CONFIG_PPC_PSERIES
567 static void rtas_percpu_suspend_me(void *info)
568 {
569 	int i;
570 	long rc;
571 	long flags;
572 	struct rtas_suspend_me_data *data =
573 		(struct rtas_suspend_me_data *)info;
574 
575 	/*
576 	 * We use "waiting" to indicate our state.  As long
577 	 * as it is >0, we are still trying to all join up.
578 	 * If it goes to 0, we have successfully joined up and
579 	 * one thread got H_Continue.  If any error happens,
580 	 * we set it to <0.
581 	 */
582 	local_irq_save(flags);
583 	do {
584 		rc = plpar_hcall_norets(H_JOIN);
585 		smp_rmb();
586 	} while (rc == H_Success && data->waiting > 0);
587 	if (rc == H_Success)
588 		goto out;
589 
590 	if (rc == H_Continue) {
591 		data->waiting = 0;
592 		data->args->args[data->args->nargs] =
593 			rtas_call(ibm_suspend_me_token, 0, 1, NULL);
594 		for_each_cpu(i)
595 			plpar_hcall_norets(H_PROD,i);
596 	} else {
597 		data->waiting = -EBUSY;
598 		printk(KERN_ERR "Error on H_Join hypervisor call\n");
599 	}
600 
601 out:
602 	local_irq_restore(flags);
603 	return;
604 }
605 
606 static int rtas_ibm_suspend_me(struct rtas_args *args)
607 {
608 	int i;
609 
610 	struct rtas_suspend_me_data data;
611 
612 	data.waiting = 1;
613 	data.args = args;
614 
615 	/* Call function on all CPUs.  One of us will make the
616 	 * rtas call
617 	 */
618 	if (on_each_cpu(rtas_percpu_suspend_me, &data, 1, 0))
619 		data.waiting = -EINVAL;
620 
621 	if (data.waiting != 0)
622 		printk(KERN_ERR "Error doing global join\n");
623 
624 	/* Prod each CPU.  This won't hurt, and will wake
625 	 * anyone we successfully put to sleep with H_Join
626 	 */
627 	for_each_cpu(i)
628 		plpar_hcall_norets(H_PROD, i);
629 
630 	return data.waiting;
631 }
632 #else /* CONFIG_PPC_PSERIES */
633 static int rtas_ibm_suspend_me(struct rtas_args *args)
634 {
635 	return -ENOSYS;
636 }
637 #endif
638 
639 asmlinkage int ppc_rtas(struct rtas_args __user *uargs)
640 {
641 	struct rtas_args args;
642 	unsigned long flags;
643 	char *buff_copy, *errbuf = NULL;
644 	int nargs;
645 	int rc;
646 
647 	if (!capable(CAP_SYS_ADMIN))
648 		return -EPERM;
649 
650 	if (copy_from_user(&args, uargs, 3 * sizeof(u32)) != 0)
651 		return -EFAULT;
652 
653 	nargs = args.nargs;
654 	if (nargs > ARRAY_SIZE(args.args)
655 	    || args.nret > ARRAY_SIZE(args.args)
656 	    || nargs + args.nret > ARRAY_SIZE(args.args))
657 		return -EINVAL;
658 
659 	/* Copy in args. */
660 	if (copy_from_user(args.args, uargs->args,
661 			   nargs * sizeof(rtas_arg_t)) != 0)
662 		return -EFAULT;
663 
664 	if (args.token == RTAS_UNKNOWN_SERVICE)
665 		return -EINVAL;
666 
667 	/* Need to handle ibm,suspend_me call specially */
668 	if (args.token == ibm_suspend_me_token) {
669 		rc = rtas_ibm_suspend_me(&args);
670 		if (rc)
671 			return rc;
672 		goto copy_return;
673 	}
674 
675 	buff_copy = get_errorlog_buffer();
676 
677 	spin_lock_irqsave(&rtas.lock, flags);
678 
679 	rtas.args = args;
680 	enter_rtas(__pa(&rtas.args));
681 	args = rtas.args;
682 
683 	args.rets = &args.args[nargs];
684 
685 	/* A -1 return code indicates that the last command couldn't
686 	   be completed due to a hardware error. */
687 	if (args.rets[0] == -1)
688 		errbuf = __fetch_rtas_last_error(buff_copy);
689 
690 	spin_unlock_irqrestore(&rtas.lock, flags);
691 
692 	if (buff_copy) {
693 		if (errbuf)
694 			log_error(errbuf, ERR_TYPE_RTAS_LOG, 0);
695 		kfree(buff_copy);
696 	}
697 
698  copy_return:
699 	/* Copy out args. */
700 	if (copy_to_user(uargs->args + nargs,
701 			 args.args + nargs,
702 			 args.nret * sizeof(rtas_arg_t)) != 0)
703 		return -EFAULT;
704 
705 	return 0;
706 }
707 
708 /* This version can't take the spinlock, because it never returns */
709 
710 struct rtas_args rtas_stop_self_args = {
711 	/* The token is initialized for real in setup_system() */
712 	.token = RTAS_UNKNOWN_SERVICE,
713 	.nargs = 0,
714 	.nret = 1,
715 	.rets = &rtas_stop_self_args.args[0],
716 };
717 
718 void rtas_stop_self(void)
719 {
720 	struct rtas_args *rtas_args = &rtas_stop_self_args;
721 
722 	local_irq_disable();
723 
724 	BUG_ON(rtas_args->token == RTAS_UNKNOWN_SERVICE);
725 
726 	printk("cpu %u (hwid %u) Ready to die...\n",
727 	       smp_processor_id(), hard_smp_processor_id());
728 	enter_rtas(__pa(rtas_args));
729 
730 	panic("Alas, I survived.\n");
731 }
732 
733 /*
734  * Call early during boot, before mem init or bootmem, to retrieve the RTAS
735  * informations from the device-tree and allocate the RMO buffer for userland
736  * accesses.
737  */
738 void __init rtas_initialize(void)
739 {
740 	unsigned long rtas_region = RTAS_INSTANTIATE_MAX;
741 
742 	/* Get RTAS dev node and fill up our "rtas" structure with infos
743 	 * about it.
744 	 */
745 	rtas.dev = of_find_node_by_name(NULL, "rtas");
746 	if (rtas.dev) {
747 		u32 *basep, *entryp;
748 		u32 *sizep;
749 
750 		basep = (u32 *)get_property(rtas.dev, "linux,rtas-base", NULL);
751 		sizep = (u32 *)get_property(rtas.dev, "rtas-size", NULL);
752 		if (basep != NULL && sizep != NULL) {
753 			rtas.base = *basep;
754 			rtas.size = *sizep;
755 			entryp = (u32 *)get_property(rtas.dev, "linux,rtas-entry", NULL);
756 			if (entryp == NULL) /* Ugh */
757 				rtas.entry = rtas.base;
758 			else
759 				rtas.entry = *entryp;
760 		} else
761 			rtas.dev = NULL;
762 	}
763 	if (!rtas.dev)
764 		return;
765 
766 	/* If RTAS was found, allocate the RMO buffer for it and look for
767 	 * the stop-self token if any
768 	 */
769 #ifdef CONFIG_PPC64
770 	if (_machine == PLATFORM_PSERIES_LPAR) {
771 		rtas_region = min(lmb.rmo_size, RTAS_INSTANTIATE_MAX);
772 		ibm_suspend_me_token = rtas_token("ibm,suspend-me");
773 	}
774 #endif
775 	rtas_rmo_buf = lmb_alloc_base(RTAS_RMOBUF_MAX, PAGE_SIZE, rtas_region);
776 
777 #ifdef CONFIG_HOTPLUG_CPU
778 	rtas_stop_self_args.token = rtas_token("stop-self");
779 #endif /* CONFIG_HOTPLUG_CPU */
780 #ifdef CONFIG_RTAS_ERROR_LOGGING
781 	rtas_last_error_token = rtas_token("rtas-last-error");
782 #endif
783 }
784 
785 
786 EXPORT_SYMBOL(rtas_token);
787 EXPORT_SYMBOL(rtas_call);
788 EXPORT_SYMBOL(rtas_data_buf);
789 EXPORT_SYMBOL(rtas_data_buf_lock);
790 EXPORT_SYMBOL(rtas_extended_busy_delay_time);
791 EXPORT_SYMBOL(rtas_get_sensor);
792 EXPORT_SYMBOL(rtas_get_power_level);
793 EXPORT_SYMBOL(rtas_set_power_level);
794 EXPORT_SYMBOL(rtas_set_indicator);
795