xref: /linux/drivers/parisc/led.c (revision d524dac9279b6a41ffdf7ff7958c577f2e387db6)
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 2001-2009 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/seq_file.h>
42 #include <linux/ctype.h>
43 #include <linux/blkdev.h>
44 #include <linux/workqueue.h>
45 #include <linux/rcupdate.h>
46 #include <asm/io.h>
47 #include <asm/processor.h>
48 #include <asm/hardware.h>
49 #include <asm/param.h>		/* HZ */
50 #include <asm/led.h>
51 #include <asm/pdc.h>
52 #include <asm/uaccess.h>
53 
54 /* The control of the LEDs and LCDs on PARISC-machines have to be done
55    completely in software. The necessary calculations are done in a work queue
56    task which is scheduled regularly, and since the calculations may consume a
57    relatively large amount of CPU time, some of the calculations can be
58    turned off with the following variables (controlled via procfs) */
59 
60 static int led_type __read_mostly = -1;
61 static unsigned char lastleds;	/* LED state from most recent update */
62 static unsigned int led_heartbeat __read_mostly = 1;
63 static unsigned int led_diskio    __read_mostly = 1;
64 static unsigned int led_lanrxtx   __read_mostly = 1;
65 static char lcd_text[32]          __read_mostly;
66 static char lcd_text_default[32]  __read_mostly;
67 static int  lcd_no_led_support    __read_mostly = 0; /* KittyHawk doesn't support LED on its LCD */
68 
69 
70 static struct workqueue_struct *led_wq;
71 static void led_work_func(struct work_struct *);
72 static DECLARE_DELAYED_WORK(led_task, led_work_func);
73 
74 #if 0
75 #define DPRINTK(x)	printk x
76 #else
77 #define DPRINTK(x)
78 #endif
79 
80 struct lcd_block {
81 	unsigned char command;	/* stores the command byte      */
82 	unsigned char on;	/* value for turning LED on     */
83 	unsigned char off;	/* value for turning LED off    */
84 };
85 
86 /* Structure returned by PDC_RETURN_CHASSIS_INFO */
87 /* NOTE: we use unsigned long:16 two times, since the following member
88    lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
89 struct pdc_chassis_lcd_info_ret_block {
90 	unsigned long model:16;		/* DISPLAY_MODEL_XXXX */
91 	unsigned long lcd_width:16;	/* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
92 	unsigned long lcd_cmd_reg_addr;	/* ptr to LCD cmd-register & data ptr for LED */
93 	unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
94 	unsigned int min_cmd_delay;	/* delay in uS after cmd-write (LCD only) */
95 	unsigned char reset_cmd1;	/* command #1 for writing LCD string (LCD only) */
96 	unsigned char reset_cmd2;	/* command #2 for writing LCD string (LCD only) */
97 	unsigned char act_enable;	/* 0 = no activity (LCD only) */
98 	struct lcd_block heartbeat;
99 	struct lcd_block disk_io;
100 	struct lcd_block lan_rcv;
101 	struct lcd_block lan_tx;
102 	char _pad;
103 };
104 
105 
106 /* LCD_CMD and LCD_DATA for KittyHawk machines */
107 #define KITTYHAWK_LCD_CMD  F_EXTEND(0xf0190000UL) /* 64bit-ready */
108 #define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD+1)
109 
110 /* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's
111  * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
112 static struct pdc_chassis_lcd_info_ret_block
113 lcd_info __attribute__((aligned(8))) __read_mostly =
114 {
115 	.model =		DISPLAY_MODEL_LCD,
116 	.lcd_width =		16,
117 	.lcd_cmd_reg_addr =	KITTYHAWK_LCD_CMD,
118 	.lcd_data_reg_addr =	KITTYHAWK_LCD_DATA,
119 	.min_cmd_delay =	80,
120 	.reset_cmd1 =		0x80,
121 	.reset_cmd2 =		0xc0,
122 };
123 
124 
125 /* direct access to some of the lcd_info variables */
126 #define LCD_CMD_REG	lcd_info.lcd_cmd_reg_addr
127 #define LCD_DATA_REG	lcd_info.lcd_data_reg_addr
128 #define LED_DATA_REG	lcd_info.lcd_cmd_reg_addr	/* LASI & ASP only */
129 
130 #define LED_HASLCD 1
131 #define LED_NOLCD  0
132 
133 /* The workqueue must be created at init-time */
134 static int start_task(void)
135 {
136 	/* Display the default text now */
137 	if (led_type == LED_HASLCD) lcd_print( lcd_text_default );
138 
139 	/* KittyHawk has no LED support on its LCD */
140 	if (lcd_no_led_support) return 0;
141 
142 	/* Create the work queue and queue the LED task */
143 	led_wq = create_singlethread_workqueue("led_wq");
144 	queue_delayed_work(led_wq, &led_task, 0);
145 
146 	return 0;
147 }
148 
149 device_initcall(start_task);
150 
151 /* ptr to LCD/LED-specific function */
152 static void (*led_func_ptr) (unsigned char) __read_mostly;
153 
154 #ifdef CONFIG_PROC_FS
155 static int led_proc_show(struct seq_file *m, void *v)
156 {
157 	switch ((long)m->private)
158 	{
159 	case LED_NOLCD:
160 		seq_printf(m, "Heartbeat: %d\n", led_heartbeat);
161 		seq_printf(m, "Disk IO: %d\n", led_diskio);
162 		seq_printf(m, "LAN Rx/Tx: %d\n", led_lanrxtx);
163 		break;
164 	case LED_HASLCD:
165 		seq_printf(m, "%s\n", lcd_text);
166 		break;
167 	default:
168 		return 0;
169 	}
170 	return 0;
171 }
172 
173 static int led_proc_open(struct inode *inode, struct file *file)
174 {
175 	return single_open(file, led_proc_show, PDE(inode)->data);
176 }
177 
178 
179 static ssize_t led_proc_write(struct file *file, const char *buf,
180 	size_t count, loff_t *pos)
181 {
182 	void *data = PDE(file->f_path.dentry->d_inode)->data;
183 	char *cur, lbuf[32];
184 	int d;
185 
186 	if (!capable(CAP_SYS_ADMIN))
187 		return -EACCES;
188 
189 	if (count >= sizeof(lbuf))
190 		count = sizeof(lbuf)-1;
191 
192 	if (copy_from_user(lbuf, buf, count))
193 		return -EFAULT;
194 	lbuf[count] = 0;
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 const struct file_operations led_proc_fops = {
238 	.owner		= THIS_MODULE,
239 	.open		= led_proc_open,
240 	.read		= seq_read,
241 	.llseek		= seq_lseek,
242 	.release	= single_release,
243 	.write		= led_proc_write,
244 };
245 
246 static int __init led_create_procfs(void)
247 {
248 	struct proc_dir_entry *proc_pdc_root = NULL;
249 	struct proc_dir_entry *ent;
250 
251 	if (led_type == -1) return -1;
252 
253 	proc_pdc_root = proc_mkdir("pdc", 0);
254 	if (!proc_pdc_root) return -1;
255 
256 	if (!lcd_no_led_support)
257 	{
258 		ent = proc_create_data("led", S_IRUGO|S_IWUSR, proc_pdc_root,
259 					&led_proc_fops, (void *)LED_NOLCD); /* LED */
260 		if (!ent) return -1;
261 	}
262 
263 	if (led_type == LED_HASLCD)
264 	{
265 		ent = proc_create_data("lcd", S_IRUGO|S_IWUSR, proc_pdc_root,
266 					&led_proc_fops, (void *)LED_HASLCD); /* LCD */
267 		if (!ent) return -1;
268 	}
269 
270 	return 0;
271 }
272 #endif
273 
274 /*
275    **
276    ** led_ASP_driver()
277    **
278  */
279 #define	LED_DATA	0x01	/* data to shift (0:on 1:off) */
280 #define	LED_STROBE	0x02	/* strobe to clock data */
281 static void led_ASP_driver(unsigned char leds)
282 {
283 	int i;
284 
285 	leds = ~leds;
286 	for (i = 0; i < 8; i++) {
287 		unsigned char value;
288 		value = (leds & 0x80) >> 7;
289 		gsc_writeb( value,		 LED_DATA_REG );
290 		gsc_writeb( value | LED_STROBE,	 LED_DATA_REG );
291 		leds <<= 1;
292 	}
293 }
294 
295 
296 /*
297    **
298    ** led_LASI_driver()
299    **
300  */
301 static void led_LASI_driver(unsigned char leds)
302 {
303 	leds = ~leds;
304 	gsc_writeb( leds, LED_DATA_REG );
305 }
306 
307 
308 /*
309    **
310    ** led_LCD_driver()
311    **
312  */
313 static void led_LCD_driver(unsigned char leds)
314 {
315 	static int i;
316 	static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
317 		LED_LAN_RCV, LED_LAN_TX };
318 
319 	static struct lcd_block * blockp[4] = {
320 		&lcd_info.heartbeat,
321 		&lcd_info.disk_io,
322 		&lcd_info.lan_rcv,
323 		&lcd_info.lan_tx
324 	};
325 
326 	/* Convert min_cmd_delay to milliseconds */
327 	unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
328 
329 	for (i=0; i<4; ++i)
330 	{
331 		if ((leds & mask[i]) != (lastleds & mask[i]))
332 		{
333 			gsc_writeb( blockp[i]->command, LCD_CMD_REG );
334 			msleep(msec_cmd_delay);
335 
336 			gsc_writeb( leds & mask[i] ? blockp[i]->on :
337 					blockp[i]->off, LCD_DATA_REG );
338 			msleep(msec_cmd_delay);
339 		}
340 	}
341 }
342 
343 
344 /*
345    **
346    ** led_get_net_activity()
347    **
348    ** calculate if there was TX- or RX-throughput on the network interfaces
349    ** (analog to dev_get_info() from net/core/dev.c)
350    **
351  */
352 static __inline__ int led_get_net_activity(void)
353 {
354 #ifndef CONFIG_NET
355 	return 0;
356 #else
357 	static u64 rx_total_last, tx_total_last;
358 	u64 rx_total, tx_total;
359 	struct net_device *dev;
360 	int retval;
361 
362 	rx_total = tx_total = 0;
363 
364 	/* we are running as a workqueue task, so we can use an RCU lookup */
365 	rcu_read_lock();
366 	for_each_netdev_rcu(&init_net, dev) {
367 	    const struct rtnl_link_stats64 *stats;
368 	    struct rtnl_link_stats64 temp;
369 	    struct in_device *in_dev = __in_dev_get_rcu(dev);
370 	    if (!in_dev || !in_dev->ifa_list)
371 		continue;
372 	    if (ipv4_is_loopback(in_dev->ifa_list->ifa_local))
373 		continue;
374 	    stats = dev_get_stats(dev, &temp);
375 	    rx_total += stats->rx_packets;
376 	    tx_total += stats->tx_packets;
377 	}
378 	rcu_read_unlock();
379 
380 	retval = 0;
381 
382 	if (rx_total != rx_total_last) {
383 		rx_total_last = rx_total;
384 		retval |= LED_LAN_RCV;
385 	}
386 
387 	if (tx_total != tx_total_last) {
388 		tx_total_last = tx_total;
389 		retval |= LED_LAN_TX;
390 	}
391 
392 	return retval;
393 #endif
394 }
395 
396 
397 /*
398    **
399    ** led_get_diskio_activity()
400    **
401    ** calculate if there was disk-io in the system
402    **
403  */
404 static __inline__ int led_get_diskio_activity(void)
405 {
406 	static unsigned long last_pgpgin, last_pgpgout;
407 	unsigned long events[NR_VM_EVENT_ITEMS];
408 	int changed;
409 
410 	all_vm_events(events);
411 
412 	/* Just use a very simple calculation here. Do not care about overflow,
413 	   since we only want to know if there was activity or not. */
414 	changed = (events[PGPGIN] != last_pgpgin) ||
415 		  (events[PGPGOUT] != last_pgpgout);
416 	last_pgpgin  = events[PGPGIN];
417 	last_pgpgout = events[PGPGOUT];
418 
419 	return (changed ? LED_DISK_IO : 0);
420 }
421 
422 
423 
424 /*
425    ** led_work_func()
426    **
427    ** manages when and which chassis LCD/LED gets updated
428 
429     TODO:
430     - display load average (older machines like 715/64 have 4 "free" LED's for that)
431     - optimizations
432  */
433 
434 #define HEARTBEAT_LEN (HZ*10/100)
435 #define HEARTBEAT_2ND_RANGE_START (HZ*28/100)
436 #define HEARTBEAT_2ND_RANGE_END   (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)
437 
438 #define LED_UPDATE_INTERVAL (1 + (HZ*19/1000))
439 
440 static void led_work_func (struct work_struct *unused)
441 {
442 	static unsigned long last_jiffies;
443 	static unsigned long count_HZ; /* counter in range 0..HZ */
444 	unsigned char currentleds = 0; /* stores current value of the LEDs */
445 
446 	/* exit if not initialized */
447 	if (!led_func_ptr)
448 	    return;
449 
450 	/* increment the heartbeat timekeeper */
451 	count_HZ += jiffies - last_jiffies;
452 	last_jiffies = jiffies;
453 	if (count_HZ >= HZ)
454 	    count_HZ = 0;
455 
456 	if (likely(led_heartbeat))
457 	{
458 		/* flash heartbeat-LED like a real heart
459 		 * (2 x short then a long delay)
460 		 */
461 		if (count_HZ < HEARTBEAT_LEN ||
462 				(count_HZ >= HEARTBEAT_2ND_RANGE_START &&
463 				count_HZ < HEARTBEAT_2ND_RANGE_END))
464 			currentleds |= LED_HEARTBEAT;
465 	}
466 
467 	if (likely(led_lanrxtx))  currentleds |= led_get_net_activity();
468 	if (likely(led_diskio))   currentleds |= led_get_diskio_activity();
469 
470 	/* blink LEDs if we got an Oops (HPMC) */
471 	if (unlikely(oops_in_progress)) {
472 		if (boot_cpu_data.cpu_type >= pcxl2) {
473 			/* newer machines don't have loadavg. LEDs, so we
474 			 * let all LEDs blink twice per second instead */
475 			currentleds = (count_HZ <= (HZ/2)) ? 0 : 0xff;
476 		} else {
477 			/* old machines: blink loadavg. LEDs twice per second */
478 			if (count_HZ <= (HZ/2))
479 				currentleds &= ~(LED4|LED5|LED6|LED7);
480 			else
481 				currentleds |= (LED4|LED5|LED6|LED7);
482 		}
483 	}
484 
485 	if (currentleds != lastleds)
486 	{
487 		led_func_ptr(currentleds);	/* Update the LCD/LEDs */
488 		lastleds = currentleds;
489 	}
490 
491 	queue_delayed_work(led_wq, &led_task, LED_UPDATE_INTERVAL);
492 }
493 
494 /*
495    ** led_halt()
496    **
497    ** called by the reboot notifier chain at shutdown and stops all
498    ** LED/LCD activities.
499    **
500  */
501 
502 static int led_halt(struct notifier_block *, unsigned long, void *);
503 
504 static struct notifier_block led_notifier = {
505 	.notifier_call = led_halt,
506 };
507 static int notifier_disabled = 0;
508 
509 static int led_halt(struct notifier_block *nb, unsigned long event, void *buf)
510 {
511 	char *txt;
512 
513 	if (notifier_disabled)
514 		return NOTIFY_OK;
515 
516 	notifier_disabled = 1;
517 	switch (event) {
518 	case SYS_RESTART:	txt = "SYSTEM RESTART";
519 				break;
520 	case SYS_HALT:		txt = "SYSTEM HALT";
521 				break;
522 	case SYS_POWER_OFF:	txt = "SYSTEM POWER OFF";
523 				break;
524 	default:		return NOTIFY_DONE;
525 	}
526 
527 	/* Cancel the work item and delete the queue */
528 	if (led_wq) {
529 		cancel_delayed_work_sync(&led_task);
530 		destroy_workqueue(led_wq);
531 		led_wq = NULL;
532 	}
533 
534 	if (lcd_info.model == DISPLAY_MODEL_LCD)
535 		lcd_print(txt);
536 	else
537 		if (led_func_ptr)
538 			led_func_ptr(0xff); /* turn all LEDs ON */
539 
540 	return NOTIFY_OK;
541 }
542 
543 /*
544    ** register_led_driver()
545    **
546    ** registers an external LED or LCD for usage by this driver.
547    ** currently only LCD-, LASI- and ASP-style LCD/LED's are supported.
548    **
549  */
550 
551 int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
552 {
553 	static int initialized;
554 
555 	if (initialized || !data_reg)
556 		return 1;
557 
558 	lcd_info.model = model;		/* store the values */
559 	LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;
560 
561 	switch (lcd_info.model) {
562 	case DISPLAY_MODEL_LCD:
563 		LCD_DATA_REG = data_reg;
564 		printk(KERN_INFO "LCD display at %lx,%lx registered\n",
565 			LCD_CMD_REG , LCD_DATA_REG);
566 		led_func_ptr = led_LCD_driver;
567 		led_type = LED_HASLCD;
568 		break;
569 
570 	case DISPLAY_MODEL_LASI:
571 		LED_DATA_REG = data_reg;
572 		led_func_ptr = led_LASI_driver;
573 		printk(KERN_INFO "LED display at %lx registered\n", LED_DATA_REG);
574 		led_type = LED_NOLCD;
575 		break;
576 
577 	case DISPLAY_MODEL_OLD_ASP:
578 		LED_DATA_REG = data_reg;
579 		led_func_ptr = led_ASP_driver;
580 		printk(KERN_INFO "LED (ASP-style) display at %lx registered\n",
581 		    LED_DATA_REG);
582 		led_type = LED_NOLCD;
583 		break;
584 
585 	default:
586 		printk(KERN_ERR "%s: Wrong LCD/LED model %d !\n",
587 		       __func__, lcd_info.model);
588 		return 1;
589 	}
590 
591 	/* mark the LCD/LED driver now as initialized and
592 	 * register to the reboot notifier chain */
593 	initialized++;
594 	register_reboot_notifier(&led_notifier);
595 
596 	/* Ensure the work is queued */
597 	if (led_wq) {
598 		queue_delayed_work(led_wq, &led_task, 0);
599 	}
600 
601 	return 0;
602 }
603 
604 /*
605    ** register_led_regions()
606    **
607    ** register_led_regions() registers the LCD/LED regions for /procfs.
608    ** At bootup - where the initialisation of the LCD/LED normally happens -
609    ** not all internal structures of request_region() are properly set up,
610    ** so that we delay the led-registration until after busdevices_init()
611    ** has been executed.
612    **
613  */
614 
615 void __init register_led_regions(void)
616 {
617 	switch (lcd_info.model) {
618 	case DISPLAY_MODEL_LCD:
619 		request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
620 		request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
621 		break;
622 	case DISPLAY_MODEL_LASI:
623 	case DISPLAY_MODEL_OLD_ASP:
624 		request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
625 		break;
626 	}
627 }
628 
629 
630 /*
631    **
632    ** lcd_print()
633    **
634    ** Displays the given string on the LCD-Display of newer machines.
635    ** lcd_print() disables/enables the timer-based led work queue to
636    ** avoid a race condition while writing the CMD/DATA register pair.
637    **
638  */
639 int lcd_print( const char *str )
640 {
641 	int i;
642 
643 	if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
644 	    return 0;
645 
646 	/* temporarily disable the led work task */
647 	if (led_wq)
648 		cancel_delayed_work_sync(&led_task);
649 
650 	/* copy display string to buffer for procfs */
651 	strlcpy(lcd_text, str, sizeof(lcd_text));
652 
653 	/* Set LCD Cursor to 1st character */
654 	gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
655 	udelay(lcd_info.min_cmd_delay);
656 
657 	/* Print the string */
658 	for (i=0; i < lcd_info.lcd_width; i++) {
659 	    if (str && *str)
660 		gsc_writeb(*str++, LCD_DATA_REG);
661 	    else
662 		gsc_writeb(' ', LCD_DATA_REG);
663 	    udelay(lcd_info.min_cmd_delay);
664 	}
665 
666 	/* re-queue the work */
667 	if (led_wq) {
668 		queue_delayed_work(led_wq, &led_task, 0);
669 	}
670 
671 	return lcd_info.lcd_width;
672 }
673 
674 /*
675    ** led_init()
676    **
677    ** led_init() is called very early in the bootup-process from setup.c
678    ** and asks the PDC for an usable chassis LCD or LED.
679    ** If the PDC doesn't return any info, then the LED
680    ** is detected by lasi.c or asp.c and registered with the
681    ** above functions lasi_led_init() or asp_led_init().
682    ** KittyHawk machines have often a buggy PDC, so that
683    ** we explicitly check for those machines here.
684  */
685 
686 int __init led_init(void)
687 {
688 	struct pdc_chassis_info chassis_info;
689 	int ret;
690 
691 	snprintf(lcd_text_default, sizeof(lcd_text_default),
692 		"Linux %s", init_utsname()->release);
693 
694 	/* Work around the buggy PDC of KittyHawk-machines */
695 	switch (CPU_HVERSION) {
696 	case 0x580:		/* KittyHawk DC2-100 (K100) */
697 	case 0x581:		/* KittyHawk DC3-120 (K210) */
698 	case 0x582:		/* KittyHawk DC3 100 (K400) */
699 	case 0x583:		/* KittyHawk DC3 120 (K410) */
700 	case 0x58B:		/* KittyHawk DC2 100 (K200) */
701 		printk(KERN_INFO "%s: KittyHawk-Machine (hversion 0x%x) found, "
702 				"LED detection skipped.\n", __FILE__, CPU_HVERSION);
703 		lcd_no_led_support = 1;
704 		goto found;	/* use the preinitialized values of lcd_info */
705 	}
706 
707 	/* initialize the struct, so that we can check for valid return values */
708 	lcd_info.model = DISPLAY_MODEL_NONE;
709 	chassis_info.actcnt = chassis_info.maxcnt = 0;
710 
711 	ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
712 	if (ret == PDC_OK) {
713 		DPRINTK((KERN_INFO "%s: chassis info: model=%d (%s), "
714 			 "lcd_width=%d, cmd_delay=%u,\n"
715 			 "%s: sizecnt=%d, actcnt=%ld, maxcnt=%ld\n",
716 		         __FILE__, lcd_info.model,
717 			 (lcd_info.model==DISPLAY_MODEL_LCD) ? "LCD" :
718 			  (lcd_info.model==DISPLAY_MODEL_LASI) ? "LED" : "unknown",
719 			 lcd_info.lcd_width, lcd_info.min_cmd_delay,
720 			 __FILE__, sizeof(lcd_info),
721 			 chassis_info.actcnt, chassis_info.maxcnt));
722 		DPRINTK((KERN_INFO "%s: cmd=%p, data=%p, reset1=%x, reset2=%x, act_enable=%d\n",
723 			__FILE__, lcd_info.lcd_cmd_reg_addr,
724 			lcd_info.lcd_data_reg_addr, lcd_info.reset_cmd1,
725 			lcd_info.reset_cmd2, lcd_info.act_enable ));
726 
727 		/* check the results. Some machines have a buggy PDC */
728 		if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
729 			goto not_found;
730 
731 		switch (lcd_info.model) {
732 		case DISPLAY_MODEL_LCD:		/* LCD display */
733 			if (chassis_info.actcnt <
734 				offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
735 				goto not_found;
736 			if (!lcd_info.act_enable) {
737 				DPRINTK((KERN_INFO "PDC prohibited usage of the LCD.\n"));
738 				goto not_found;
739 			}
740 			break;
741 
742 		case DISPLAY_MODEL_NONE:	/* no LED or LCD available */
743 			printk(KERN_INFO "PDC reported no LCD or LED.\n");
744 			goto not_found;
745 
746 		case DISPLAY_MODEL_LASI:	/* Lasi style 8 bit LED display */
747 			if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
748 				goto not_found;
749 			break;
750 
751 		default:
752 			printk(KERN_WARNING "PDC reported unknown LCD/LED model %d\n",
753 			       lcd_info.model);
754 			goto not_found;
755 		} /* switch() */
756 
757 found:
758 		/* register the LCD/LED driver */
759 		register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
760 		return 0;
761 
762 	} else { /* if() */
763 		DPRINTK((KERN_INFO "pdc_chassis_info call failed with retval = %d\n", ret));
764 	}
765 
766 not_found:
767 	lcd_info.model = DISPLAY_MODEL_NONE;
768 	return 1;
769 }
770 
771 static void __exit led_exit(void)
772 {
773 	unregister_reboot_notifier(&led_notifier);
774 	return;
775 }
776 
777 #ifdef CONFIG_PROC_FS
778 module_init(led_create_procfs)
779 #endif
780