xref: /openbmc/linux/drivers/parisc/led.c (revision 367b8112)
1 /*
2  *    Chassis LCD/LED driver for HP-PARISC workstations
3  *
4  *      (c) Copyright 2000 Red Hat Software
5  *      (c) Copyright 2000 Helge Deller <hdeller@redhat.com>
6  *      (c) Copyright 2001-2005 Helge Deller <deller@gmx.de>
7  *      (c) Copyright 2001 Randolph Chung <tausq@debian.org>
8  *
9  *      This program is free software; you can redistribute it and/or modify
10  *      it under the terms of the GNU General Public License as published by
11  *      the Free Software Foundation; either version 2 of the License, or
12  *      (at your option) any later version.
13  *
14  * TODO:
15  *	- speed-up calculations with inlined assembler
16  *	- interface to write to second row of LCD from /proc (if technically possible)
17  *
18  * Changes:
19  *      - Audit copy_from_user in led_proc_write.
20  *                                Daniele Bellucci <bellucda@tiscali.it>
21  *	- Switch from using a tasklet to a work queue, so the led_LCD_driver
22  *	  	can sleep.
23  *	  			  David Pye <dmp@davidmpye.dyndns.org>
24  */
25 
26 #include <linux/module.h>
27 #include <linux/stddef.h>	/* for offsetof() */
28 #include <linux/init.h>
29 #include <linux/types.h>
30 #include <linux/ioport.h>
31 #include <linux/utsname.h>
32 #include <linux/capability.h>
33 #include <linux/delay.h>
34 #include <linux/netdevice.h>
35 #include <linux/inetdevice.h>
36 #include <linux/in.h>
37 #include <linux/interrupt.h>
38 #include <linux/kernel_stat.h>
39 #include <linux/reboot.h>
40 #include <linux/proc_fs.h>
41 #include <linux/ctype.h>
42 #include <linux/blkdev.h>
43 #include <linux/workqueue.h>
44 #include <linux/rcupdate.h>
45 #include <asm/io.h>
46 #include <asm/processor.h>
47 #include <asm/hardware.h>
48 #include <asm/param.h>		/* HZ */
49 #include <asm/led.h>
50 #include <asm/pdc.h>
51 #include <asm/uaccess.h>
52 
53 /* The control of the LEDs and LCDs on PARISC-machines have to be done
54    completely in software. The necessary calculations are done in a work queue
55    task which is scheduled regularly, and since the calculations may consume a
56    relatively large amount of CPU time, some of the calculations can be
57    turned off with the following variables (controlled via procfs) */
58 
59 static int led_type __read_mostly = -1;
60 static unsigned char lastleds;	/* LED state from most recent update */
61 static unsigned int led_heartbeat __read_mostly = 1;
62 static unsigned int led_diskio    __read_mostly = 1;
63 static unsigned int led_lanrxtx   __read_mostly = 1;
64 static char lcd_text[32]          __read_mostly;
65 static char lcd_text_default[32]  __read_mostly;
66 
67 
68 static struct workqueue_struct *led_wq;
69 static void led_work_func(struct work_struct *);
70 static DECLARE_DELAYED_WORK(led_task, led_work_func);
71 
72 #if 0
73 #define DPRINTK(x)	printk x
74 #else
75 #define DPRINTK(x)
76 #endif
77 
78 struct lcd_block {
79 	unsigned char command;	/* stores the command byte      */
80 	unsigned char on;	/* value for turning LED on     */
81 	unsigned char off;	/* value for turning LED off    */
82 };
83 
84 /* Structure returned by PDC_RETURN_CHASSIS_INFO */
85 /* NOTE: we use unsigned long:16 two times, since the following member
86    lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
87 struct pdc_chassis_lcd_info_ret_block {
88 	unsigned long model:16;		/* DISPLAY_MODEL_XXXX */
89 	unsigned long lcd_width:16;	/* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
90 	unsigned long lcd_cmd_reg_addr;	/* ptr to LCD cmd-register & data ptr for LED */
91 	unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
92 	unsigned int min_cmd_delay;	/* delay in uS after cmd-write (LCD only) */
93 	unsigned char reset_cmd1;	/* command #1 for writing LCD string (LCD only) */
94 	unsigned char reset_cmd2;	/* command #2 for writing LCD string (LCD only) */
95 	unsigned char act_enable;	/* 0 = no activity (LCD only) */
96 	struct lcd_block heartbeat;
97 	struct lcd_block disk_io;
98 	struct lcd_block lan_rcv;
99 	struct lcd_block lan_tx;
100 	char _pad;
101 };
102 
103 
104 /* LCD_CMD and LCD_DATA for KittyHawk machines */
105 #define KITTYHAWK_LCD_CMD  F_EXTEND(0xf0190000UL) /* 64bit-ready */
106 #define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD+1)
107 
108 /* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's
109  * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
110 static struct pdc_chassis_lcd_info_ret_block
111 lcd_info __attribute__((aligned(8))) __read_mostly =
112 {
113 	.model =		DISPLAY_MODEL_LCD,
114 	.lcd_width =		16,
115 	.lcd_cmd_reg_addr =	KITTYHAWK_LCD_CMD,
116 	.lcd_data_reg_addr =	KITTYHAWK_LCD_DATA,
117 	.min_cmd_delay =	40,
118 	.reset_cmd1 =		0x80,
119 	.reset_cmd2 =		0xc0,
120 };
121 
122 
123 /* direct access to some of the lcd_info variables */
124 #define LCD_CMD_REG	lcd_info.lcd_cmd_reg_addr
125 #define LCD_DATA_REG	lcd_info.lcd_data_reg_addr
126 #define LED_DATA_REG	lcd_info.lcd_cmd_reg_addr	/* LASI & ASP only */
127 
128 #define LED_HASLCD 1
129 #define LED_NOLCD  0
130 
131 /* The workqueue must be created at init-time */
132 static int start_task(void)
133 {
134 	/* Display the default text now */
135 	if (led_type == LED_HASLCD) lcd_print( lcd_text_default );
136 
137 	/* Create the work queue and queue the LED task */
138 	led_wq = create_singlethread_workqueue("led_wq");
139 	queue_delayed_work(led_wq, &led_task, 0);
140 
141 	return 0;
142 }
143 
144 device_initcall(start_task);
145 
146 /* ptr to LCD/LED-specific function */
147 static void (*led_func_ptr) (unsigned char) __read_mostly;
148 
149 #ifdef CONFIG_PROC_FS
150 static int led_proc_read(char *page, char **start, off_t off, int count,
151 	int *eof, void *data)
152 {
153 	char *out = page;
154 	int len;
155 
156 	switch ((long)data)
157 	{
158 	case LED_NOLCD:
159 		out += sprintf(out, "Heartbeat: %d\n", led_heartbeat);
160 		out += sprintf(out, "Disk IO: %d\n", led_diskio);
161 		out += sprintf(out, "LAN Rx/Tx: %d\n", led_lanrxtx);
162 		break;
163 	case LED_HASLCD:
164 		out += sprintf(out, "%s\n", lcd_text);
165 		break;
166 	default:
167 		*eof = 1;
168 		return 0;
169 	}
170 
171 	len = out - page - off;
172 	if (len < count) {
173 		*eof = 1;
174 		if (len <= 0) return 0;
175 	} else {
176 		len = count;
177 	}
178 	*start = page + off;
179 	return len;
180 }
181 
182 static int led_proc_write(struct file *file, const char *buf,
183 	unsigned long count, void *data)
184 {
185 	char *cur, lbuf[count + 1];
186 	int d;
187 
188 	if (!capable(CAP_SYS_ADMIN))
189 		return -EACCES;
190 
191 	memset(lbuf, 0, count + 1);
192 
193 	if (copy_from_user(lbuf, buf, count))
194 		return -EFAULT;
195 
196 	cur = lbuf;
197 
198 	switch ((long)data)
199 	{
200 	case LED_NOLCD:
201 		d = *cur++ - '0';
202 		if (d != 0 && d != 1) goto parse_error;
203 		led_heartbeat = d;
204 
205 		if (*cur++ != ' ') goto parse_error;
206 
207 		d = *cur++ - '0';
208 		if (d != 0 && d != 1) goto parse_error;
209 		led_diskio = d;
210 
211 		if (*cur++ != ' ') goto parse_error;
212 
213 		d = *cur++ - '0';
214 		if (d != 0 && d != 1) goto parse_error;
215 		led_lanrxtx = d;
216 
217 		break;
218 	case LED_HASLCD:
219 		if (*cur && cur[strlen(cur)-1] == '\n')
220 			cur[strlen(cur)-1] = 0;
221 		if (*cur == 0)
222 			cur = lcd_text_default;
223 		lcd_print(cur);
224 		break;
225 	default:
226 		return 0;
227 	}
228 
229 	return count;
230 
231 parse_error:
232 	if ((long)data == LED_NOLCD)
233 		printk(KERN_CRIT "Parse error: expect \"n n n\" (n == 0 or 1) for heartbeat,\ndisk io and lan tx/rx indicators\n");
234 	return -EINVAL;
235 }
236 
237 static int __init led_create_procfs(void)
238 {
239 	struct proc_dir_entry *proc_pdc_root = NULL;
240 	struct proc_dir_entry *ent;
241 
242 	if (led_type == -1) return -1;
243 
244 	proc_pdc_root = proc_mkdir("pdc", 0);
245 	if (!proc_pdc_root) return -1;
246 	proc_pdc_root->owner = THIS_MODULE;
247 	ent = create_proc_entry("led", S_IFREG|S_IRUGO|S_IWUSR, proc_pdc_root);
248 	if (!ent) return -1;
249 	ent->data = (void *)LED_NOLCD; /* LED */
250 	ent->read_proc = led_proc_read;
251 	ent->write_proc = led_proc_write;
252 	ent->owner = THIS_MODULE;
253 
254 	if (led_type == LED_HASLCD)
255 	{
256 		ent = create_proc_entry("lcd", S_IFREG|S_IRUGO|S_IWUSR, proc_pdc_root);
257 		if (!ent) return -1;
258 		ent->data = (void *)LED_HASLCD; /* LCD */
259 		ent->read_proc = led_proc_read;
260 		ent->write_proc = led_proc_write;
261 		ent->owner = THIS_MODULE;
262 	}
263 
264 	return 0;
265 }
266 #endif
267 
268 /*
269    **
270    ** led_ASP_driver()
271    **
272  */
273 #define	LED_DATA	0x01	/* data to shift (0:on 1:off) */
274 #define	LED_STROBE	0x02	/* strobe to clock data */
275 static void led_ASP_driver(unsigned char leds)
276 {
277 	int i;
278 
279 	leds = ~leds;
280 	for (i = 0; i < 8; i++) {
281 		unsigned char value;
282 		value = (leds & 0x80) >> 7;
283 		gsc_writeb( value,		 LED_DATA_REG );
284 		gsc_writeb( value | LED_STROBE,	 LED_DATA_REG );
285 		leds <<= 1;
286 	}
287 }
288 
289 
290 /*
291    **
292    ** led_LASI_driver()
293    **
294  */
295 static void led_LASI_driver(unsigned char leds)
296 {
297 	leds = ~leds;
298 	gsc_writeb( leds, LED_DATA_REG );
299 }
300 
301 
302 /*
303    **
304    ** led_LCD_driver()
305    **
306  */
307 static void led_LCD_driver(unsigned char leds)
308 {
309 	static int i;
310 	static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
311 		LED_LAN_RCV, LED_LAN_TX };
312 
313 	static struct lcd_block * blockp[4] = {
314 		&lcd_info.heartbeat,
315 		&lcd_info.disk_io,
316 		&lcd_info.lan_rcv,
317 		&lcd_info.lan_tx
318 	};
319 
320 	/* Convert min_cmd_delay to milliseconds */
321 	unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
322 
323 	for (i=0; i<4; ++i)
324 	{
325 		if ((leds & mask[i]) != (lastleds & mask[i]))
326 		{
327 			gsc_writeb( blockp[i]->command, LCD_CMD_REG );
328 			msleep(msec_cmd_delay);
329 
330 			gsc_writeb( leds & mask[i] ? blockp[i]->on :
331 					blockp[i]->off, LCD_DATA_REG );
332 			msleep(msec_cmd_delay);
333 		}
334 	}
335 }
336 
337 
338 /*
339    **
340    ** led_get_net_activity()
341    **
342    ** calculate if there was TX- or RX-throughput on the network interfaces
343    ** (analog to dev_get_info() from net/core/dev.c)
344    **
345  */
346 static __inline__ int led_get_net_activity(void)
347 {
348 #ifndef CONFIG_NET
349 	return 0;
350 #else
351 	static unsigned long rx_total_last, tx_total_last;
352 	unsigned long rx_total, tx_total;
353 	struct net_device *dev;
354 	int retval;
355 
356 	rx_total = tx_total = 0;
357 
358 	/* we are running as a workqueue task, so locking dev_base
359 	 * for reading should be OK */
360 	read_lock(&dev_base_lock);
361 	rcu_read_lock();
362 	for_each_netdev(&init_net, dev) {
363 	    struct net_device_stats *stats;
364 	    struct in_device *in_dev = __in_dev_get_rcu(dev);
365 	    if (!in_dev || !in_dev->ifa_list)
366 		continue;
367 	    if (ipv4_is_loopback(in_dev->ifa_list->ifa_local))
368 		continue;
369 	    stats = dev->get_stats(dev);
370 	    rx_total += stats->rx_packets;
371 	    tx_total += stats->tx_packets;
372 	}
373 	rcu_read_unlock();
374 	read_unlock(&dev_base_lock);
375 
376 	retval = 0;
377 
378 	if (rx_total != rx_total_last) {
379 		rx_total_last = rx_total;
380 		retval |= LED_LAN_RCV;
381 	}
382 
383 	if (tx_total != tx_total_last) {
384 		tx_total_last = tx_total;
385 		retval |= LED_LAN_TX;
386 	}
387 
388 	return retval;
389 #endif
390 }
391 
392 
393 /*
394    **
395    ** led_get_diskio_activity()
396    **
397    ** calculate if there was disk-io in the system
398    **
399  */
400 static __inline__ int led_get_diskio_activity(void)
401 {
402 	static unsigned long last_pgpgin, last_pgpgout;
403 	unsigned long events[NR_VM_EVENT_ITEMS];
404 	int changed;
405 
406 	all_vm_events(events);
407 
408 	/* Just use a very simple calculation here. Do not care about overflow,
409 	   since we only want to know if there was activity or not. */
410 	changed = (events[PGPGIN] != last_pgpgin) ||
411 		  (events[PGPGOUT] != last_pgpgout);
412 	last_pgpgin  = events[PGPGIN];
413 	last_pgpgout = events[PGPGOUT];
414 
415 	return (changed ? LED_DISK_IO : 0);
416 }
417 
418 
419 
420 /*
421    ** led_work_func()
422    **
423    ** manages when and which chassis LCD/LED gets updated
424 
425     TODO:
426     - display load average (older machines like 715/64 have 4 "free" LED's for that)
427     - optimizations
428  */
429 
430 #define HEARTBEAT_LEN (HZ*10/100)
431 #define HEARTBEAT_2ND_RANGE_START (HZ*28/100)
432 #define HEARTBEAT_2ND_RANGE_END   (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)
433 
434 #define LED_UPDATE_INTERVAL (1 + (HZ*19/1000))
435 
436 static void led_work_func (struct work_struct *unused)
437 {
438 	static unsigned long last_jiffies;
439 	static unsigned long count_HZ; /* counter in range 0..HZ */
440 	unsigned char currentleds = 0; /* stores current value of the LEDs */
441 
442 	/* exit if not initialized */
443 	if (!led_func_ptr)
444 	    return;
445 
446 	/* increment the heartbeat timekeeper */
447 	count_HZ += jiffies - last_jiffies;
448 	last_jiffies = jiffies;
449 	if (count_HZ >= HZ)
450 	    count_HZ = 0;
451 
452 	if (likely(led_heartbeat))
453 	{
454 		/* flash heartbeat-LED like a real heart
455 		 * (2 x short then a long delay)
456 		 */
457 		if (count_HZ < HEARTBEAT_LEN ||
458 				(count_HZ >= HEARTBEAT_2ND_RANGE_START &&
459 				count_HZ < HEARTBEAT_2ND_RANGE_END))
460 			currentleds |= LED_HEARTBEAT;
461 	}
462 
463 	if (likely(led_lanrxtx))  currentleds |= led_get_net_activity();
464 	if (likely(led_diskio))   currentleds |= led_get_diskio_activity();
465 
466 	/* blink all LEDs twice a second if we got an Oops (HPMC) */
467 	if (unlikely(oops_in_progress))
468 		currentleds = (count_HZ<=(HZ/2)) ? 0 : 0xff;
469 
470 	if (currentleds != lastleds)
471 	{
472 		led_func_ptr(currentleds);	/* Update the LCD/LEDs */
473 		lastleds = currentleds;
474 	}
475 
476 	queue_delayed_work(led_wq, &led_task, LED_UPDATE_INTERVAL);
477 }
478 
479 /*
480    ** led_halt()
481    **
482    ** called by the reboot notifier chain at shutdown and stops all
483    ** LED/LCD activities.
484    **
485  */
486 
487 static int led_halt(struct notifier_block *, unsigned long, void *);
488 
489 static struct notifier_block led_notifier = {
490 	.notifier_call = led_halt,
491 };
492 static int notifier_disabled = 0;
493 
494 static int led_halt(struct notifier_block *nb, unsigned long event, void *buf)
495 {
496 	char *txt;
497 
498 	if (notifier_disabled)
499 		return NOTIFY_OK;
500 
501 	notifier_disabled = 1;
502 	switch (event) {
503 	case SYS_RESTART:	txt = "SYSTEM RESTART";
504 				break;
505 	case SYS_HALT:		txt = "SYSTEM HALT";
506 				break;
507 	case SYS_POWER_OFF:	txt = "SYSTEM POWER OFF";
508 				break;
509 	default:		return NOTIFY_DONE;
510 	}
511 
512 	/* Cancel the work item and delete the queue */
513 	if (led_wq) {
514 		cancel_rearming_delayed_workqueue(led_wq, &led_task);
515 		destroy_workqueue(led_wq);
516 		led_wq = NULL;
517 	}
518 
519 	if (lcd_info.model == DISPLAY_MODEL_LCD)
520 		lcd_print(txt);
521 	else
522 		if (led_func_ptr)
523 			led_func_ptr(0xff); /* turn all LEDs ON */
524 
525 	return NOTIFY_OK;
526 }
527 
528 /*
529    ** register_led_driver()
530    **
531    ** registers an external LED or LCD for usage by this driver.
532    ** currently only LCD-, LASI- and ASP-style LCD/LED's are supported.
533    **
534  */
535 
536 int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
537 {
538 	static int initialized;
539 
540 	if (initialized || !data_reg)
541 		return 1;
542 
543 	lcd_info.model = model;		/* store the values */
544 	LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;
545 
546 	switch (lcd_info.model) {
547 	case DISPLAY_MODEL_LCD:
548 		LCD_DATA_REG = data_reg;
549 		printk(KERN_INFO "LCD display at %lx,%lx registered\n",
550 			LCD_CMD_REG , LCD_DATA_REG);
551 		led_func_ptr = led_LCD_driver;
552 		led_type = LED_HASLCD;
553 		break;
554 
555 	case DISPLAY_MODEL_LASI:
556 		LED_DATA_REG = data_reg;
557 		led_func_ptr = led_LASI_driver;
558 		printk(KERN_INFO "LED display at %lx registered\n", LED_DATA_REG);
559 		led_type = LED_NOLCD;
560 		break;
561 
562 	case DISPLAY_MODEL_OLD_ASP:
563 		LED_DATA_REG = data_reg;
564 		led_func_ptr = led_ASP_driver;
565 		printk(KERN_INFO "LED (ASP-style) display at %lx registered\n",
566 		    LED_DATA_REG);
567 		led_type = LED_NOLCD;
568 		break;
569 
570 	default:
571 		printk(KERN_ERR "%s: Wrong LCD/LED model %d !\n",
572 		       __func__, lcd_info.model);
573 		return 1;
574 	}
575 
576 	/* mark the LCD/LED driver now as initialized and
577 	 * register to the reboot notifier chain */
578 	initialized++;
579 	register_reboot_notifier(&led_notifier);
580 
581 	/* Ensure the work is queued */
582 	if (led_wq) {
583 		queue_delayed_work(led_wq, &led_task, 0);
584 	}
585 
586 	return 0;
587 }
588 
589 /*
590    ** register_led_regions()
591    **
592    ** register_led_regions() registers the LCD/LED regions for /procfs.
593    ** At bootup - where the initialisation of the LCD/LED normally happens -
594    ** not all internal structures of request_region() are properly set up,
595    ** so that we delay the led-registration until after busdevices_init()
596    ** has been executed.
597    **
598  */
599 
600 void __init register_led_regions(void)
601 {
602 	switch (lcd_info.model) {
603 	case DISPLAY_MODEL_LCD:
604 		request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
605 		request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
606 		break;
607 	case DISPLAY_MODEL_LASI:
608 	case DISPLAY_MODEL_OLD_ASP:
609 		request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
610 		break;
611 	}
612 }
613 
614 
615 /*
616    **
617    ** lcd_print()
618    **
619    ** Displays the given string on the LCD-Display of newer machines.
620    ** lcd_print() disables/enables the timer-based led work queue to
621    ** avoid a race condition while writing the CMD/DATA register pair.
622    **
623  */
624 int lcd_print( const char *str )
625 {
626 	int i;
627 
628 	if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
629 	    return 0;
630 
631 	/* temporarily disable the led work task */
632 	if (led_wq)
633 		cancel_rearming_delayed_workqueue(led_wq, &led_task);
634 
635 	/* copy display string to buffer for procfs */
636 	strlcpy(lcd_text, str, sizeof(lcd_text));
637 
638 	/* Set LCD Cursor to 1st character */
639 	gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
640 	udelay(lcd_info.min_cmd_delay);
641 
642 	/* Print the string */
643 	for (i=0; i < lcd_info.lcd_width; i++) {
644 	    if (str && *str)
645 		gsc_writeb(*str++, LCD_DATA_REG);
646 	    else
647 		gsc_writeb(' ', LCD_DATA_REG);
648 	    udelay(lcd_info.min_cmd_delay);
649 	}
650 
651 	/* re-queue the work */
652 	if (led_wq) {
653 		queue_delayed_work(led_wq, &led_task, 0);
654 	}
655 
656 	return lcd_info.lcd_width;
657 }
658 
659 /*
660    ** led_init()
661    **
662    ** led_init() is called very early in the bootup-process from setup.c
663    ** and asks the PDC for an usable chassis LCD or LED.
664    ** If the PDC doesn't return any info, then the LED
665    ** is detected by lasi.c or asp.c and registered with the
666    ** above functions lasi_led_init() or asp_led_init().
667    ** KittyHawk machines have often a buggy PDC, so that
668    ** we explicitly check for those machines here.
669  */
670 
671 int __init led_init(void)
672 {
673 	struct pdc_chassis_info chassis_info;
674 	int ret;
675 
676 	snprintf(lcd_text_default, sizeof(lcd_text_default),
677 		"Linux %s", init_utsname()->release);
678 
679 	/* Work around the buggy PDC of KittyHawk-machines */
680 	switch (CPU_HVERSION) {
681 	case 0x580:		/* KittyHawk DC2-100 (K100) */
682 	case 0x581:		/* KittyHawk DC3-120 (K210) */
683 	case 0x582:		/* KittyHawk DC3 100 (K400) */
684 	case 0x583:		/* KittyHawk DC3 120 (K410) */
685 	case 0x58B:		/* KittyHawk DC2 100 (K200) */
686 		printk(KERN_INFO "%s: KittyHawk-Machine (hversion 0x%x) found, "
687 				"LED detection skipped.\n", __FILE__, CPU_HVERSION);
688 		goto found;	/* use the preinitialized values of lcd_info */
689 	}
690 
691 	/* initialize the struct, so that we can check for valid return values */
692 	lcd_info.model = DISPLAY_MODEL_NONE;
693 	chassis_info.actcnt = chassis_info.maxcnt = 0;
694 
695 	ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
696 	if (ret == PDC_OK) {
697 		DPRINTK((KERN_INFO "%s: chassis info: model=%d (%s), "
698 			 "lcd_width=%d, cmd_delay=%u,\n"
699 			 "%s: sizecnt=%d, actcnt=%ld, maxcnt=%ld\n",
700 		         __FILE__, lcd_info.model,
701 			 (lcd_info.model==DISPLAY_MODEL_LCD) ? "LCD" :
702 			  (lcd_info.model==DISPLAY_MODEL_LASI) ? "LED" : "unknown",
703 			 lcd_info.lcd_width, lcd_info.min_cmd_delay,
704 			 __FILE__, sizeof(lcd_info),
705 			 chassis_info.actcnt, chassis_info.maxcnt));
706 		DPRINTK((KERN_INFO "%s: cmd=%p, data=%p, reset1=%x, reset2=%x, act_enable=%d\n",
707 			__FILE__, lcd_info.lcd_cmd_reg_addr,
708 			lcd_info.lcd_data_reg_addr, lcd_info.reset_cmd1,
709 			lcd_info.reset_cmd2, lcd_info.act_enable ));
710 
711 		/* check the results. Some machines have a buggy PDC */
712 		if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
713 			goto not_found;
714 
715 		switch (lcd_info.model) {
716 		case DISPLAY_MODEL_LCD:		/* LCD display */
717 			if (chassis_info.actcnt <
718 				offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
719 				goto not_found;
720 			if (!lcd_info.act_enable) {
721 				DPRINTK((KERN_INFO "PDC prohibited usage of the LCD.\n"));
722 				goto not_found;
723 			}
724 			break;
725 
726 		case DISPLAY_MODEL_NONE:	/* no LED or LCD available */
727 			printk(KERN_INFO "PDC reported no LCD or LED.\n");
728 			goto not_found;
729 
730 		case DISPLAY_MODEL_LASI:	/* Lasi style 8 bit LED display */
731 			if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
732 				goto not_found;
733 			break;
734 
735 		default:
736 			printk(KERN_WARNING "PDC reported unknown LCD/LED model %d\n",
737 			       lcd_info.model);
738 			goto not_found;
739 		} /* switch() */
740 
741 found:
742 		/* register the LCD/LED driver */
743 		register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
744 		return 0;
745 
746 	} else { /* if() */
747 		DPRINTK((KERN_INFO "pdc_chassis_info call failed with retval = %d\n", ret));
748 	}
749 
750 not_found:
751 	lcd_info.model = DISPLAY_MODEL_NONE;
752 	return 1;
753 }
754 
755 static void __exit led_exit(void)
756 {
757 	unregister_reboot_notifier(&led_notifier);
758 	return;
759 }
760 
761 #ifdef CONFIG_PROC_FS
762 module_init(led_create_procfs)
763 #endif
764