xref: /openbmc/linux/drivers/parisc/led.c (revision 7f6964c5)
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 file_operations led_proc_fops = {
234 	.owner		= THIS_MODULE,
235 	.open		= led_proc_open,
236 	.read		= seq_read,
237 	.llseek		= seq_lseek,
238 	.release	= single_release,
239 	.write		= led_proc_write,
240 };
241 
242 static int __init led_create_procfs(void)
243 {
244 	struct proc_dir_entry *proc_pdc_root = NULL;
245 	struct proc_dir_entry *ent;
246 
247 	if (led_type == -1) return -1;
248 
249 	proc_pdc_root = proc_mkdir("pdc", NULL);
250 	if (!proc_pdc_root) return -1;
251 
252 	if (!lcd_no_led_support)
253 	{
254 		ent = proc_create_data("led", S_IRUGO|S_IWUSR, proc_pdc_root,
255 					&led_proc_fops, (void *)LED_NOLCD); /* LED */
256 		if (!ent) return -1;
257 	}
258 
259 	if (led_type == LED_HASLCD)
260 	{
261 		ent = proc_create_data("lcd", S_IRUGO|S_IWUSR, proc_pdc_root,
262 					&led_proc_fops, (void *)LED_HASLCD); /* LCD */
263 		if (!ent) return -1;
264 	}
265 
266 	return 0;
267 }
268 #endif
269 
270 /*
271    **
272    ** led_ASP_driver()
273    **
274  */
275 #define	LED_DATA	0x01	/* data to shift (0:on 1:off) */
276 #define	LED_STROBE	0x02	/* strobe to clock data */
277 static void led_ASP_driver(unsigned char leds)
278 {
279 	int i;
280 
281 	leds = ~leds;
282 	for (i = 0; i < 8; i++) {
283 		unsigned char value;
284 		value = (leds & 0x80) >> 7;
285 		gsc_writeb( value,		 LED_DATA_REG );
286 		gsc_writeb( value | LED_STROBE,	 LED_DATA_REG );
287 		leds <<= 1;
288 	}
289 }
290 
291 
292 /*
293    **
294    ** led_LASI_driver()
295    **
296  */
297 static void led_LASI_driver(unsigned char leds)
298 {
299 	leds = ~leds;
300 	gsc_writeb( leds, LED_DATA_REG );
301 }
302 
303 
304 /*
305    **
306    ** led_LCD_driver()
307    **
308  */
309 static void led_LCD_driver(unsigned char leds)
310 {
311 	static int i;
312 	static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
313 		LED_LAN_RCV, LED_LAN_TX };
314 
315 	static struct lcd_block * blockp[4] = {
316 		&lcd_info.heartbeat,
317 		&lcd_info.disk_io,
318 		&lcd_info.lan_rcv,
319 		&lcd_info.lan_tx
320 	};
321 
322 	/* Convert min_cmd_delay to milliseconds */
323 	unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
324 
325 	for (i=0; i<4; ++i)
326 	{
327 		if ((leds & mask[i]) != (lastleds & mask[i]))
328 		{
329 			gsc_writeb( blockp[i]->command, LCD_CMD_REG );
330 			msleep(msec_cmd_delay);
331 
332 			gsc_writeb( leds & mask[i] ? blockp[i]->on :
333 					blockp[i]->off, LCD_DATA_REG );
334 			msleep(msec_cmd_delay);
335 		}
336 	}
337 }
338 
339 
340 /*
341    **
342    ** led_get_net_activity()
343    **
344    ** calculate if there was TX- or RX-throughput on the network interfaces
345    ** (analog to dev_get_info() from net/core/dev.c)
346    **
347  */
348 static __inline__ int led_get_net_activity(void)
349 {
350 #ifndef CONFIG_NET
351 	return 0;
352 #else
353 	static u64 rx_total_last, tx_total_last;
354 	u64 rx_total, tx_total;
355 	struct net_device *dev;
356 	int retval;
357 
358 	rx_total = tx_total = 0;
359 
360 	/* we are running as a workqueue task, so we can use an RCU lookup */
361 	rcu_read_lock();
362 	for_each_netdev_rcu(&init_net, dev) {
363 	    const struct rtnl_link_stats64 *stats;
364 	    struct rtnl_link_stats64 temp;
365 	    struct in_device *in_dev = __in_dev_get_rcu(dev);
366 	    if (!in_dev || !in_dev->ifa_list)
367 		continue;
368 	    if (ipv4_is_loopback(in_dev->ifa_list->ifa_local))
369 		continue;
370 	    stats = dev_get_stats(dev, &temp);
371 	    rx_total += stats->rx_packets;
372 	    tx_total += stats->tx_packets;
373 	}
374 	rcu_read_unlock();
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 LEDs if we got an Oops (HPMC) */
467 	if (unlikely(oops_in_progress)) {
468 		if (boot_cpu_data.cpu_type >= pcxl2) {
469 			/* newer machines don't have loadavg. LEDs, so we
470 			 * let all LEDs blink twice per second instead */
471 			currentleds = (count_HZ <= (HZ/2)) ? 0 : 0xff;
472 		} else {
473 			/* old machines: blink loadavg. LEDs twice per second */
474 			if (count_HZ <= (HZ/2))
475 				currentleds &= ~(LED4|LED5|LED6|LED7);
476 			else
477 				currentleds |= (LED4|LED5|LED6|LED7);
478 		}
479 	}
480 
481 	if (currentleds != lastleds)
482 	{
483 		led_func_ptr(currentleds);	/* Update the LCD/LEDs */
484 		lastleds = currentleds;
485 	}
486 
487 	queue_delayed_work(led_wq, &led_task, LED_UPDATE_INTERVAL);
488 }
489 
490 /*
491    ** led_halt()
492    **
493    ** called by the reboot notifier chain at shutdown and stops all
494    ** LED/LCD activities.
495    **
496  */
497 
498 static int led_halt(struct notifier_block *, unsigned long, void *);
499 
500 static struct notifier_block led_notifier = {
501 	.notifier_call = led_halt,
502 };
503 static int notifier_disabled = 0;
504 
505 static int led_halt(struct notifier_block *nb, unsigned long event, void *buf)
506 {
507 	char *txt;
508 
509 	if (notifier_disabled)
510 		return NOTIFY_OK;
511 
512 	notifier_disabled = 1;
513 	switch (event) {
514 	case SYS_RESTART:	txt = "SYSTEM RESTART";
515 				break;
516 	case SYS_HALT:		txt = "SYSTEM HALT";
517 				break;
518 	case SYS_POWER_OFF:	txt = "SYSTEM POWER OFF";
519 				break;
520 	default:		return NOTIFY_DONE;
521 	}
522 
523 	/* Cancel the work item and delete the queue */
524 	if (led_wq) {
525 		cancel_delayed_work_sync(&led_task);
526 		destroy_workqueue(led_wq);
527 		led_wq = NULL;
528 	}
529 
530 	if (lcd_info.model == DISPLAY_MODEL_LCD)
531 		lcd_print(txt);
532 	else
533 		if (led_func_ptr)
534 			led_func_ptr(0xff); /* turn all LEDs ON */
535 
536 	return NOTIFY_OK;
537 }
538 
539 /*
540    ** register_led_driver()
541    **
542    ** registers an external LED or LCD for usage by this driver.
543    ** currently only LCD-, LASI- and ASP-style LCD/LED's are supported.
544    **
545  */
546 
547 int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
548 {
549 	static int initialized;
550 
551 	if (initialized || !data_reg)
552 		return 1;
553 
554 	lcd_info.model = model;		/* store the values */
555 	LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;
556 
557 	switch (lcd_info.model) {
558 	case DISPLAY_MODEL_LCD:
559 		LCD_DATA_REG = data_reg;
560 		printk(KERN_INFO "LCD display at %lx,%lx registered\n",
561 			LCD_CMD_REG , LCD_DATA_REG);
562 		led_func_ptr = led_LCD_driver;
563 		led_type = LED_HASLCD;
564 		break;
565 
566 	case DISPLAY_MODEL_LASI:
567 		/* Skip to register LED in QEMU */
568 		if (running_on_qemu)
569 			return 1;
570 		LED_DATA_REG = data_reg;
571 		led_func_ptr = led_LASI_driver;
572 		printk(KERN_INFO "LED display at %lx registered\n", LED_DATA_REG);
573 		led_type = LED_NOLCD;
574 		break;
575 
576 	case DISPLAY_MODEL_OLD_ASP:
577 		LED_DATA_REG = data_reg;
578 		led_func_ptr = led_ASP_driver;
579 		printk(KERN_INFO "LED (ASP-style) display at %lx registered\n",
580 		    LED_DATA_REG);
581 		led_type = LED_NOLCD;
582 		break;
583 
584 	default:
585 		printk(KERN_ERR "%s: Wrong LCD/LED model %d !\n",
586 		       __func__, lcd_info.model);
587 		return 1;
588 	}
589 
590 	/* mark the LCD/LED driver now as initialized and
591 	 * register to the reboot notifier chain */
592 	initialized++;
593 	register_reboot_notifier(&led_notifier);
594 
595 	/* Ensure the work is queued */
596 	if (led_wq) {
597 		queue_delayed_work(led_wq, &led_task, 0);
598 	}
599 
600 	return 0;
601 }
602 
603 /*
604    ** register_led_regions()
605    **
606    ** register_led_regions() registers the LCD/LED regions for /procfs.
607    ** At bootup - where the initialisation of the LCD/LED normally happens -
608    ** not all internal structures of request_region() are properly set up,
609    ** so that we delay the led-registration until after busdevices_init()
610    ** has been executed.
611    **
612  */
613 
614 void __init register_led_regions(void)
615 {
616 	switch (lcd_info.model) {
617 	case DISPLAY_MODEL_LCD:
618 		request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
619 		request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
620 		break;
621 	case DISPLAY_MODEL_LASI:
622 	case DISPLAY_MODEL_OLD_ASP:
623 		request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
624 		break;
625 	}
626 }
627 
628 
629 /*
630    **
631    ** lcd_print()
632    **
633    ** Displays the given string on the LCD-Display of newer machines.
634    ** lcd_print() disables/enables the timer-based led work queue to
635    ** avoid a race condition while writing the CMD/DATA register pair.
636    **
637  */
638 int lcd_print( const char *str )
639 {
640 	int i;
641 
642 	if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
643 	    return 0;
644 
645 	/* temporarily disable the led work task */
646 	if (led_wq)
647 		cancel_delayed_work_sync(&led_task);
648 
649 	/* copy display string to buffer for procfs */
650 	strlcpy(lcd_text, str, sizeof(lcd_text));
651 
652 	/* Set LCD Cursor to 1st character */
653 	gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
654 	udelay(lcd_info.min_cmd_delay);
655 
656 	/* Print the string */
657 	for (i=0; i < lcd_info.lcd_width; i++) {
658 	    if (str && *str)
659 		gsc_writeb(*str++, LCD_DATA_REG);
660 	    else
661 		gsc_writeb(' ', LCD_DATA_REG);
662 	    udelay(lcd_info.min_cmd_delay);
663 	}
664 
665 	/* re-queue the work */
666 	if (led_wq) {
667 		queue_delayed_work(led_wq, &led_task, 0);
668 	}
669 
670 	return lcd_info.lcd_width;
671 }
672 
673 /*
674    ** led_init()
675    **
676    ** led_init() is called very early in the bootup-process from setup.c
677    ** and asks the PDC for an usable chassis LCD or LED.
678    ** If the PDC doesn't return any info, then the LED
679    ** is detected by lasi.c or asp.c and registered with the
680    ** above functions lasi_led_init() or asp_led_init().
681    ** KittyHawk machines have often a buggy PDC, so that
682    ** we explicitly check for those machines here.
683  */
684 
685 int __init led_init(void)
686 {
687 	struct pdc_chassis_info chassis_info;
688 	int ret;
689 
690 	snprintf(lcd_text_default, sizeof(lcd_text_default),
691 		"Linux %s", init_utsname()->release);
692 
693 	/* Work around the buggy PDC of KittyHawk-machines */
694 	switch (CPU_HVERSION) {
695 	case 0x580:		/* KittyHawk DC2-100 (K100) */
696 	case 0x581:		/* KittyHawk DC3-120 (K210) */
697 	case 0x582:		/* KittyHawk DC3 100 (K400) */
698 	case 0x583:		/* KittyHawk DC3 120 (K410) */
699 	case 0x58B:		/* KittyHawk DC2 100 (K200) */
700 		printk(KERN_INFO "%s: KittyHawk-Machine (hversion 0x%x) found, "
701 				"LED detection skipped.\n", __FILE__, CPU_HVERSION);
702 		lcd_no_led_support = 1;
703 		goto found;	/* use the preinitialized values of lcd_info */
704 	}
705 
706 	/* initialize the struct, so that we can check for valid return values */
707 	lcd_info.model = DISPLAY_MODEL_NONE;
708 	chassis_info.actcnt = chassis_info.maxcnt = 0;
709 
710 	ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
711 	if (ret == PDC_OK) {
712 		DPRINTK((KERN_INFO "%s: chassis info: model=%d (%s), "
713 			 "lcd_width=%d, cmd_delay=%u,\n"
714 			 "%s: sizecnt=%d, actcnt=%ld, maxcnt=%ld\n",
715 		         __FILE__, lcd_info.model,
716 			 (lcd_info.model==DISPLAY_MODEL_LCD) ? "LCD" :
717 			  (lcd_info.model==DISPLAY_MODEL_LASI) ? "LED" : "unknown",
718 			 lcd_info.lcd_width, lcd_info.min_cmd_delay,
719 			 __FILE__, sizeof(lcd_info),
720 			 chassis_info.actcnt, chassis_info.maxcnt));
721 		DPRINTK((KERN_INFO "%s: cmd=%p, data=%p, reset1=%x, reset2=%x, act_enable=%d\n",
722 			__FILE__, lcd_info.lcd_cmd_reg_addr,
723 			lcd_info.lcd_data_reg_addr, lcd_info.reset_cmd1,
724 			lcd_info.reset_cmd2, lcd_info.act_enable ));
725 
726 		/* check the results. Some machines have a buggy PDC */
727 		if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
728 			goto not_found;
729 
730 		switch (lcd_info.model) {
731 		case DISPLAY_MODEL_LCD:		/* LCD display */
732 			if (chassis_info.actcnt <
733 				offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
734 				goto not_found;
735 			if (!lcd_info.act_enable) {
736 				DPRINTK((KERN_INFO "PDC prohibited usage of the LCD.\n"));
737 				goto not_found;
738 			}
739 			break;
740 
741 		case DISPLAY_MODEL_NONE:	/* no LED or LCD available */
742 			printk(KERN_INFO "PDC reported no LCD or LED.\n");
743 			goto not_found;
744 
745 		case DISPLAY_MODEL_LASI:	/* Lasi style 8 bit LED display */
746 			if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
747 				goto not_found;
748 			break;
749 
750 		default:
751 			printk(KERN_WARNING "PDC reported unknown LCD/LED model %d\n",
752 			       lcd_info.model);
753 			goto not_found;
754 		} /* switch() */
755 
756 found:
757 		/* register the LCD/LED driver */
758 		register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
759 		return 0;
760 
761 	} else { /* if() */
762 		DPRINTK((KERN_INFO "pdc_chassis_info call failed with retval = %d\n", ret));
763 	}
764 
765 not_found:
766 	lcd_info.model = DISPLAY_MODEL_NONE;
767 	return 1;
768 }
769 
770 static void __exit led_exit(void)
771 {
772 	unregister_reboot_notifier(&led_notifier);
773 	return;
774 }
775 
776 #ifdef CONFIG_PROC_FS
777 module_init(led_create_procfs)
778 #endif
779