xref: /openbmc/linux/drivers/parisc/led.c (revision e40573a4)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *    Chassis LCD/LED driver for HP-PARISC workstations
4  *
5  *      (c) Copyright 2000 Red Hat Software
6  *      (c) Copyright 2000 Helge Deller <hdeller@redhat.com>
7  *      (c) Copyright 2001-2009 Helge Deller <deller@gmx.de>
8  *      (c) Copyright 2001 Randolph Chung <tausq@debian.org>
9  *
10  * TODO:
11  *	- speed-up calculations with inlined assembler
12  *	- interface to write to second row of LCD from /proc (if technically possible)
13  *
14  * Changes:
15  *      - Audit copy_from_user in led_proc_write.
16  *                                Daniele Bellucci <bellucda@tiscali.it>
17  *	- Switch from using a tasklet to a work queue, so the led_LCD_driver
18  *	  	can sleep.
19  *	  			  David Pye <dmp@davidmpye.dyndns.org>
20  */
21 
22 #include <linux/module.h>
23 #include <linux/stddef.h>	/* for offsetof() */
24 #include <linux/init.h>
25 #include <linux/types.h>
26 #include <linux/ioport.h>
27 #include <linux/utsname.h>
28 #include <linux/capability.h>
29 #include <linux/delay.h>
30 #include <linux/netdevice.h>
31 #include <linux/inetdevice.h>
32 #include <linux/in.h>
33 #include <linux/interrupt.h>
34 #include <linux/kernel_stat.h>
35 #include <linux/reboot.h>
36 #include <linux/proc_fs.h>
37 #include <linux/seq_file.h>
38 #include <linux/ctype.h>
39 #include <linux/blkdev.h>
40 #include <linux/workqueue.h>
41 #include <linux/rcupdate.h>
42 #include <asm/io.h>
43 #include <asm/processor.h>
44 #include <asm/hardware.h>
45 #include <asm/param.h>		/* HZ */
46 #include <asm/led.h>
47 #include <asm/pdc.h>
48 #include <linux/uaccess.h>
49 
50 /* The control of the LEDs and LCDs on PARISC-machines have to be done
51    completely in software. The necessary calculations are done in a work queue
52    task which is scheduled regularly, and since the calculations may consume a
53    relatively large amount of CPU time, some of the calculations can be
54    turned off with the following variables (controlled via procfs) */
55 
56 static int led_type __read_mostly = -1;
57 static unsigned char lastleds;	/* LED state from most recent update */
58 static unsigned int led_heartbeat __read_mostly = 1;
59 static unsigned int led_diskio    __read_mostly = 1;
60 static unsigned int led_lanrxtx   __read_mostly = 1;
61 static char lcd_text[32]          __read_mostly;
62 static char lcd_text_default[32]  __read_mostly;
63 static int  lcd_no_led_support    __read_mostly = 0; /* KittyHawk doesn't support LED on its LCD */
64 
65 
66 static struct workqueue_struct *led_wq;
67 static void led_work_func(struct work_struct *);
68 static DECLARE_DELAYED_WORK(led_task, led_work_func);
69 
70 #if 0
71 #define DPRINTK(x)	printk x
72 #else
73 #define DPRINTK(x)
74 #endif
75 
76 struct lcd_block {
77 	unsigned char command;	/* stores the command byte      */
78 	unsigned char on;	/* value for turning LED on     */
79 	unsigned char off;	/* value for turning LED off    */
80 };
81 
82 /* Structure returned by PDC_RETURN_CHASSIS_INFO */
83 /* NOTE: we use unsigned long:16 two times, since the following member
84    lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
85 struct pdc_chassis_lcd_info_ret_block {
86 	unsigned long model:16;		/* DISPLAY_MODEL_XXXX */
87 	unsigned long lcd_width:16;	/* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
88 	unsigned long lcd_cmd_reg_addr;	/* ptr to LCD cmd-register & data ptr for LED */
89 	unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
90 	unsigned int min_cmd_delay;	/* delay in uS after cmd-write (LCD only) */
91 	unsigned char reset_cmd1;	/* command #1 for writing LCD string (LCD only) */
92 	unsigned char reset_cmd2;	/* command #2 for writing LCD string (LCD only) */
93 	unsigned char act_enable;	/* 0 = no activity (LCD only) */
94 	struct lcd_block heartbeat;
95 	struct lcd_block disk_io;
96 	struct lcd_block lan_rcv;
97 	struct lcd_block lan_tx;
98 	char _pad;
99 };
100 
101 
102 /* LCD_CMD and LCD_DATA for KittyHawk machines */
103 #define KITTYHAWK_LCD_CMD  F_EXTEND(0xf0190000UL) /* 64bit-ready */
104 #define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD+1)
105 
106 /* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's
107  * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
108 static struct pdc_chassis_lcd_info_ret_block
109 lcd_info __attribute__((aligned(8))) __read_mostly =
110 {
111 	.model =		DISPLAY_MODEL_LCD,
112 	.lcd_width =		16,
113 	.lcd_cmd_reg_addr =	KITTYHAWK_LCD_CMD,
114 	.lcd_data_reg_addr =	KITTYHAWK_LCD_DATA,
115 	.min_cmd_delay =	80,
116 	.reset_cmd1 =		0x80,
117 	.reset_cmd2 =		0xc0,
118 };
119 
120 
121 /* direct access to some of the lcd_info variables */
122 #define LCD_CMD_REG	lcd_info.lcd_cmd_reg_addr
123 #define LCD_DATA_REG	lcd_info.lcd_data_reg_addr
124 #define LED_DATA_REG	lcd_info.lcd_cmd_reg_addr	/* LASI & ASP only */
125 
126 #define LED_HASLCD 1
127 #define LED_NOLCD  0
128 
129 /* The workqueue must be created at init-time */
130 static int start_task(void)
131 {
132 	/* Display the default text now */
133 	if (led_type == LED_HASLCD) lcd_print( lcd_text_default );
134 
135 	/* KittyHawk has no LED support on its LCD */
136 	if (lcd_no_led_support) return 0;
137 
138 	/* Create the work queue and queue the LED task */
139 	led_wq = create_singlethread_workqueue("led_wq");
140 	queue_delayed_work(led_wq, &led_task, 0);
141 
142 	return 0;
143 }
144 
145 device_initcall(start_task);
146 
147 /* ptr to LCD/LED-specific function */
148 static void (*led_func_ptr) (unsigned char) __read_mostly;
149 
150 #ifdef CONFIG_PROC_FS
151 static int led_proc_show(struct seq_file *m, void *v)
152 {
153 	switch ((long)m->private)
154 	{
155 	case LED_NOLCD:
156 		seq_printf(m, "Heartbeat: %d\n", led_heartbeat);
157 		seq_printf(m, "Disk IO: %d\n", led_diskio);
158 		seq_printf(m, "LAN Rx/Tx: %d\n", led_lanrxtx);
159 		break;
160 	case LED_HASLCD:
161 		seq_printf(m, "%s\n", lcd_text);
162 		break;
163 	default:
164 		return 0;
165 	}
166 	return 0;
167 }
168 
169 static int led_proc_open(struct inode *inode, struct file *file)
170 {
171 	return single_open(file, led_proc_show, pde_data(inode));
172 }
173 
174 
175 static ssize_t led_proc_write(struct file *file, const char __user *buf,
176 	size_t count, loff_t *pos)
177 {
178 	void *data = pde_data(file_inode(file));
179 	char *cur, lbuf[32];
180 	int d;
181 
182 	if (!capable(CAP_SYS_ADMIN))
183 		return -EACCES;
184 
185 	if (count >= sizeof(lbuf))
186 		count = sizeof(lbuf)-1;
187 
188 	if (copy_from_user(lbuf, buf, count))
189 		return -EFAULT;
190 	lbuf[count] = 0;
191 
192 	cur = lbuf;
193 
194 	switch ((long)data)
195 	{
196 	case LED_NOLCD:
197 		d = *cur++ - '0';
198 		if (d != 0 && d != 1) goto parse_error;
199 		led_heartbeat = d;
200 
201 		if (*cur++ != ' ') goto parse_error;
202 
203 		d = *cur++ - '0';
204 		if (d != 0 && d != 1) goto parse_error;
205 		led_diskio = d;
206 
207 		if (*cur++ != ' ') goto parse_error;
208 
209 		d = *cur++ - '0';
210 		if (d != 0 && d != 1) goto parse_error;
211 		led_lanrxtx = d;
212 
213 		break;
214 	case LED_HASLCD:
215 		if (*cur && cur[strlen(cur)-1] == '\n')
216 			cur[strlen(cur)-1] = 0;
217 		if (*cur == 0)
218 			cur = lcd_text_default;
219 		lcd_print(cur);
220 		break;
221 	default:
222 		return 0;
223 	}
224 
225 	return count;
226 
227 parse_error:
228 	if ((long)data == LED_NOLCD)
229 		printk(KERN_CRIT "Parse error: expect \"n n n\" (n == 0 or 1) for heartbeat,\ndisk io and lan tx/rx indicators\n");
230 	return -EINVAL;
231 }
232 
233 static const struct proc_ops led_proc_ops = {
234 	.proc_open	= led_proc_open,
235 	.proc_read	= seq_read,
236 	.proc_lseek	= seq_lseek,
237 	.proc_release	= single_release,
238 	.proc_write	= led_proc_write,
239 };
240 
241 static int __init led_create_procfs(void)
242 {
243 	struct proc_dir_entry *proc_pdc_root = NULL;
244 	struct proc_dir_entry *ent;
245 
246 	if (led_type == -1) return -1;
247 
248 	proc_pdc_root = proc_mkdir("pdc", NULL);
249 	if (!proc_pdc_root) return -1;
250 
251 	if (!lcd_no_led_support)
252 	{
253 		ent = proc_create_data("led", 0644, proc_pdc_root,
254 					&led_proc_ops, (void *)LED_NOLCD); /* LED */
255 		if (!ent) return -1;
256 	}
257 
258 	if (led_type == LED_HASLCD)
259 	{
260 		ent = proc_create_data("lcd", 0644, proc_pdc_root,
261 					&led_proc_ops, (void *)LED_HASLCD); /* LCD */
262 		if (!ent) return -1;
263 	}
264 
265 	return 0;
266 }
267 #endif
268 
269 /*
270    **
271    ** led_ASP_driver()
272    **
273  */
274 #define	LED_DATA	0x01	/* data to shift (0:on 1:off) */
275 #define	LED_STROBE	0x02	/* strobe to clock data */
276 static void led_ASP_driver(unsigned char leds)
277 {
278 	int i;
279 
280 	leds = ~leds;
281 	for (i = 0; i < 8; i++) {
282 		unsigned char value;
283 		value = (leds & 0x80) >> 7;
284 		gsc_writeb( value,		 LED_DATA_REG );
285 		gsc_writeb( value | LED_STROBE,	 LED_DATA_REG );
286 		leds <<= 1;
287 	}
288 }
289 
290 
291 /*
292    **
293    ** led_LASI_driver()
294    **
295  */
296 static void led_LASI_driver(unsigned char leds)
297 {
298 	leds = ~leds;
299 	gsc_writeb( leds, LED_DATA_REG );
300 }
301 
302 
303 /*
304    **
305    ** led_LCD_driver()
306    **
307  */
308 static void led_LCD_driver(unsigned char leds)
309 {
310 	static int i;
311 	static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
312 		LED_LAN_RCV, LED_LAN_TX };
313 
314 	static struct lcd_block * blockp[4] = {
315 		&lcd_info.heartbeat,
316 		&lcd_info.disk_io,
317 		&lcd_info.lan_rcv,
318 		&lcd_info.lan_tx
319 	};
320 
321 	/* Convert min_cmd_delay to milliseconds */
322 	unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
323 
324 	for (i=0; i<4; ++i)
325 	{
326 		if ((leds & mask[i]) != (lastleds & mask[i]))
327 		{
328 			gsc_writeb( blockp[i]->command, LCD_CMD_REG );
329 			msleep(msec_cmd_delay);
330 
331 			gsc_writeb( leds & mask[i] ? blockp[i]->on :
332 					blockp[i]->off, LCD_DATA_REG );
333 			msleep(msec_cmd_delay);
334 		}
335 	}
336 }
337 
338 
339 /*
340    **
341    ** led_get_net_activity()
342    **
343    ** calculate if there was TX- or RX-throughput on the network interfaces
344    ** (analog to dev_get_info() from net/core/dev.c)
345    **
346  */
347 static __inline__ int led_get_net_activity(void)
348 {
349 #ifndef CONFIG_NET
350 	return 0;
351 #else
352 	static u64 rx_total_last, tx_total_last;
353 	u64 rx_total, tx_total;
354 	struct net_device *dev;
355 	int retval;
356 
357 	rx_total = tx_total = 0;
358 
359 	/* we are running as a workqueue task, so we can use an RCU lookup */
360 	rcu_read_lock();
361 	for_each_netdev_rcu(&init_net, dev) {
362 	    const struct rtnl_link_stats64 *stats;
363 	    struct rtnl_link_stats64 temp;
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, &temp);
370 	    rx_total += stats->rx_packets;
371 	    tx_total += stats->tx_packets;
372 	}
373 	rcu_read_unlock();
374 
375 	retval = 0;
376 
377 	if (rx_total != rx_total_last) {
378 		rx_total_last = rx_total;
379 		retval |= LED_LAN_RCV;
380 	}
381 
382 	if (tx_total != tx_total_last) {
383 		tx_total_last = tx_total;
384 		retval |= LED_LAN_TX;
385 	}
386 
387 	return retval;
388 #endif
389 }
390 
391 
392 /*
393    **
394    ** led_get_diskio_activity()
395    **
396    ** calculate if there was disk-io in the system
397    **
398  */
399 static __inline__ int led_get_diskio_activity(void)
400 {
401 	static unsigned long last_pgpgin, last_pgpgout;
402 	unsigned long events[NR_VM_EVENT_ITEMS];
403 	int changed;
404 
405 	all_vm_events(events);
406 
407 	/* Just use a very simple calculation here. Do not care about overflow,
408 	   since we only want to know if there was activity or not. */
409 	changed = (events[PGPGIN] != last_pgpgin) ||
410 		  (events[PGPGOUT] != last_pgpgout);
411 	last_pgpgin  = events[PGPGIN];
412 	last_pgpgout = events[PGPGOUT];
413 
414 	return (changed ? LED_DISK_IO : 0);
415 }
416 
417 
418 
419 /*
420    ** led_work_func()
421    **
422    ** manages when and which chassis LCD/LED gets updated
423 
424     TODO:
425     - display load average (older machines like 715/64 have 4 "free" LED's for that)
426     - optimizations
427  */
428 
429 #define HEARTBEAT_LEN (HZ*10/100)
430 #define HEARTBEAT_2ND_RANGE_START (HZ*28/100)
431 #define HEARTBEAT_2ND_RANGE_END   (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)
432 
433 #define LED_UPDATE_INTERVAL (1 + (HZ*19/1000))
434 
435 static void led_work_func (struct work_struct *unused)
436 {
437 	static unsigned long last_jiffies;
438 	static unsigned long count_HZ; /* counter in range 0..HZ */
439 	unsigned char currentleds = 0; /* stores current value of the LEDs */
440 
441 	/* exit if not initialized */
442 	if (!led_func_ptr)
443 	    return;
444 
445 	/* increment the heartbeat timekeeper */
446 	count_HZ += jiffies - last_jiffies;
447 	last_jiffies = jiffies;
448 	if (count_HZ >= HZ)
449 	    count_HZ = 0;
450 
451 	if (likely(led_heartbeat))
452 	{
453 		/* flash heartbeat-LED like a real heart
454 		 * (2 x short then a long delay)
455 		 */
456 		if (count_HZ < HEARTBEAT_LEN ||
457 				(count_HZ >= HEARTBEAT_2ND_RANGE_START &&
458 				count_HZ < HEARTBEAT_2ND_RANGE_END))
459 			currentleds |= LED_HEARTBEAT;
460 	}
461 
462 	if (likely(led_lanrxtx))  currentleds |= led_get_net_activity();
463 	if (likely(led_diskio))   currentleds |= led_get_diskio_activity();
464 
465 	/* blink LEDs if we got an Oops (HPMC) */
466 	if (unlikely(oops_in_progress)) {
467 		if (boot_cpu_data.cpu_type >= pcxl2) {
468 			/* newer machines don't have loadavg. LEDs, so we
469 			 * let all LEDs blink twice per second instead */
470 			currentleds = (count_HZ <= (HZ/2)) ? 0 : 0xff;
471 		} else {
472 			/* old machines: blink loadavg. LEDs twice per second */
473 			if (count_HZ <= (HZ/2))
474 				currentleds &= ~(LED4|LED5|LED6|LED7);
475 			else
476 				currentleds |= (LED4|LED5|LED6|LED7);
477 		}
478 	}
479 
480 	if (currentleds != lastleds)
481 	{
482 		led_func_ptr(currentleds);	/* Update the LCD/LEDs */
483 		lastleds = currentleds;
484 	}
485 
486 	queue_delayed_work(led_wq, &led_task, LED_UPDATE_INTERVAL);
487 }
488 
489 /*
490    ** led_halt()
491    **
492    ** called by the reboot notifier chain at shutdown and stops all
493    ** LED/LCD activities.
494    **
495  */
496 
497 static int led_halt(struct notifier_block *, unsigned long, void *);
498 
499 static struct notifier_block led_notifier = {
500 	.notifier_call = led_halt,
501 };
502 static int notifier_disabled = 0;
503 
504 static int led_halt(struct notifier_block *nb, unsigned long event, void *buf)
505 {
506 	char *txt;
507 
508 	if (notifier_disabled)
509 		return NOTIFY_OK;
510 
511 	notifier_disabled = 1;
512 	switch (event) {
513 	case SYS_RESTART:	txt = "SYSTEM RESTART";
514 				break;
515 	case SYS_HALT:		txt = "SYSTEM HALT";
516 				break;
517 	case SYS_POWER_OFF:	txt = "SYSTEM POWER OFF";
518 				break;
519 	default:		return NOTIFY_DONE;
520 	}
521 
522 	/* Cancel the work item and delete the queue */
523 	if (led_wq) {
524 		cancel_delayed_work_sync(&led_task);
525 		destroy_workqueue(led_wq);
526 		led_wq = NULL;
527 	}
528 
529 	if (lcd_info.model == DISPLAY_MODEL_LCD)
530 		lcd_print(txt);
531 	else
532 		if (led_func_ptr)
533 			led_func_ptr(0xff); /* turn all LEDs ON */
534 
535 	return NOTIFY_OK;
536 }
537 
538 /*
539    ** register_led_driver()
540    **
541    ** registers an external LED or LCD for usage by this driver.
542    ** currently only LCD-, LASI- and ASP-style LCD/LED's are supported.
543    **
544  */
545 
546 int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
547 {
548 	static int initialized;
549 
550 	if (initialized || !data_reg)
551 		return 1;
552 
553 	lcd_info.model = model;		/* store the values */
554 	LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;
555 
556 	switch (lcd_info.model) {
557 	case DISPLAY_MODEL_LCD:
558 		LCD_DATA_REG = data_reg;
559 		printk(KERN_INFO "LCD display at %lx,%lx registered\n",
560 			LCD_CMD_REG , LCD_DATA_REG);
561 		led_func_ptr = led_LCD_driver;
562 		led_type = LED_HASLCD;
563 		break;
564 
565 	case DISPLAY_MODEL_LASI:
566 		/* Skip to register LED in QEMU */
567 		if (running_on_qemu)
568 			return 1;
569 		LED_DATA_REG = data_reg;
570 		led_func_ptr = led_LASI_driver;
571 		printk(KERN_INFO "LED display at %lx registered\n", LED_DATA_REG);
572 		led_type = LED_NOLCD;
573 		break;
574 
575 	case DISPLAY_MODEL_OLD_ASP:
576 		LED_DATA_REG = data_reg;
577 		led_func_ptr = led_ASP_driver;
578 		printk(KERN_INFO "LED (ASP-style) display at %lx registered\n",
579 		    LED_DATA_REG);
580 		led_type = LED_NOLCD;
581 		break;
582 
583 	default:
584 		printk(KERN_ERR "%s: Wrong LCD/LED model %d !\n",
585 		       __func__, lcd_info.model);
586 		return 1;
587 	}
588 
589 	/* mark the LCD/LED driver now as initialized and
590 	 * register to the reboot notifier chain */
591 	initialized++;
592 	register_reboot_notifier(&led_notifier);
593 
594 	/* Ensure the work is queued */
595 	if (led_wq) {
596 		queue_delayed_work(led_wq, &led_task, 0);
597 	}
598 
599 	return 0;
600 }
601 
602 /*
603    ** register_led_regions()
604    **
605    ** register_led_regions() registers the LCD/LED regions for /procfs.
606    ** At bootup - where the initialisation of the LCD/LED normally happens -
607    ** not all internal structures of request_region() are properly set up,
608    ** so that we delay the led-registration until after busdevices_init()
609    ** has been executed.
610    **
611  */
612 
613 void __init register_led_regions(void)
614 {
615 	switch (lcd_info.model) {
616 	case DISPLAY_MODEL_LCD:
617 		request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
618 		request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
619 		break;
620 	case DISPLAY_MODEL_LASI:
621 	case DISPLAY_MODEL_OLD_ASP:
622 		request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
623 		break;
624 	}
625 }
626 
627 
628 /*
629    **
630    ** lcd_print()
631    **
632    ** Displays the given string on the LCD-Display of newer machines.
633    ** lcd_print() disables/enables the timer-based led work queue to
634    ** avoid a race condition while writing the CMD/DATA register pair.
635    **
636  */
637 int lcd_print( const char *str )
638 {
639 	int i;
640 
641 	if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
642 	    return 0;
643 
644 	/* temporarily disable the led work task */
645 	if (led_wq)
646 		cancel_delayed_work_sync(&led_task);
647 
648 	/* copy display string to buffer for procfs */
649 	strlcpy(lcd_text, str, sizeof(lcd_text));
650 
651 	/* Set LCD Cursor to 1st character */
652 	gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
653 	udelay(lcd_info.min_cmd_delay);
654 
655 	/* Print the string */
656 	for (i=0; i < lcd_info.lcd_width; i++) {
657 	    if (str && *str)
658 		gsc_writeb(*str++, LCD_DATA_REG);
659 	    else
660 		gsc_writeb(' ', LCD_DATA_REG);
661 	    udelay(lcd_info.min_cmd_delay);
662 	}
663 
664 	/* re-queue the work */
665 	if (led_wq) {
666 		queue_delayed_work(led_wq, &led_task, 0);
667 	}
668 
669 	return lcd_info.lcd_width;
670 }
671 
672 /*
673    ** led_init()
674    **
675    ** led_init() is called very early in the bootup-process from setup.c
676    ** and asks the PDC for an usable chassis LCD or LED.
677    ** If the PDC doesn't return any info, then the LED
678    ** is detected by lasi.c or asp.c and registered with the
679    ** above functions lasi_led_init() or asp_led_init().
680    ** KittyHawk machines have often a buggy PDC, so that
681    ** we explicitly check for those machines here.
682  */
683 
684 int __init led_init(void)
685 {
686 	struct pdc_chassis_info chassis_info;
687 	int ret;
688 
689 	snprintf(lcd_text_default, sizeof(lcd_text_default),
690 		"Linux %s", init_utsname()->release);
691 
692 	/* Work around the buggy PDC of KittyHawk-machines */
693 	switch (CPU_HVERSION) {
694 	case 0x580:		/* KittyHawk DC2-100 (K100) */
695 	case 0x581:		/* KittyHawk DC3-120 (K210) */
696 	case 0x582:		/* KittyHawk DC3 100 (K400) */
697 	case 0x583:		/* KittyHawk DC3 120 (K410) */
698 	case 0x58B:		/* KittyHawk DC2 100 (K200) */
699 		printk(KERN_INFO "%s: KittyHawk-Machine (hversion 0x%x) found, "
700 				"LED detection skipped.\n", __FILE__, CPU_HVERSION);
701 		lcd_no_led_support = 1;
702 		goto found;	/* use the preinitialized values of lcd_info */
703 	}
704 
705 	/* initialize the struct, so that we can check for valid return values */
706 	lcd_info.model = DISPLAY_MODEL_NONE;
707 	chassis_info.actcnt = chassis_info.maxcnt = 0;
708 
709 	ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
710 	if (ret == PDC_OK) {
711 		DPRINTK((KERN_INFO "%s: chassis info: model=%d (%s), "
712 			 "lcd_width=%d, cmd_delay=%u,\n"
713 			 "%s: sizecnt=%d, actcnt=%ld, maxcnt=%ld\n",
714 		         __FILE__, lcd_info.model,
715 			 (lcd_info.model==DISPLAY_MODEL_LCD) ? "LCD" :
716 			  (lcd_info.model==DISPLAY_MODEL_LASI) ? "LED" : "unknown",
717 			 lcd_info.lcd_width, lcd_info.min_cmd_delay,
718 			 __FILE__, sizeof(lcd_info),
719 			 chassis_info.actcnt, chassis_info.maxcnt));
720 		DPRINTK((KERN_INFO "%s: cmd=%p, data=%p, reset1=%x, reset2=%x, act_enable=%d\n",
721 			__FILE__, lcd_info.lcd_cmd_reg_addr,
722 			lcd_info.lcd_data_reg_addr, lcd_info.reset_cmd1,
723 			lcd_info.reset_cmd2, lcd_info.act_enable ));
724 
725 		/* check the results. Some machines have a buggy PDC */
726 		if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
727 			goto not_found;
728 
729 		switch (lcd_info.model) {
730 		case DISPLAY_MODEL_LCD:		/* LCD display */
731 			if (chassis_info.actcnt <
732 				offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
733 				goto not_found;
734 			if (!lcd_info.act_enable) {
735 				DPRINTK((KERN_INFO "PDC prohibited usage of the LCD.\n"));
736 				goto not_found;
737 			}
738 			break;
739 
740 		case DISPLAY_MODEL_NONE:	/* no LED or LCD available */
741 			printk(KERN_INFO "PDC reported no LCD or LED.\n");
742 			goto not_found;
743 
744 		case DISPLAY_MODEL_LASI:	/* Lasi style 8 bit LED display */
745 			if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
746 				goto not_found;
747 			break;
748 
749 		default:
750 			printk(KERN_WARNING "PDC reported unknown LCD/LED model %d\n",
751 			       lcd_info.model);
752 			goto not_found;
753 		} /* switch() */
754 
755 found:
756 		/* register the LCD/LED driver */
757 		register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
758 		return 0;
759 
760 	} else { /* if() */
761 		DPRINTK((KERN_INFO "pdc_chassis_info call failed with retval = %d\n", ret));
762 	}
763 
764 not_found:
765 	lcd_info.model = DISPLAY_MODEL_NONE;
766 	return 1;
767 }
768 
769 static void __exit led_exit(void)
770 {
771 	unregister_reboot_notifier(&led_notifier);
772 	return;
773 }
774 
775 #ifdef CONFIG_PROC_FS
776 module_init(led_create_procfs)
777 #endif
778