led.c 19.9 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779
/*
 *    Chassis LCD/LED driver for HP-PARISC workstations
 *
 *      (c) Copyright 2000 Red Hat Software
 *      (c) Copyright 2000 Helge Deller <hdeller@redhat.com>
 *      (c) Copyright 2001-2009 Helge Deller <deller@gmx.de>
 *      (c) Copyright 2001 Randolph Chung <tausq@debian.org>
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License as published by
 *      the Free Software Foundation; either version 2 of the License, or
 *      (at your option) any later version.
 *
 * TODO:
 *	- speed-up calculations with inlined assembler
 *	- interface to write to second row of LCD from /proc (if technically possible)
 *
 * Changes:
 *      - Audit copy_from_user in led_proc_write.
 *                                Daniele Bellucci <bellucda@tiscali.it>
 *	- Switch from using a tasklet to a work queue, so the led_LCD_driver
 *	  	can sleep.
 *	  			  David Pye <dmp@davidmpye.dyndns.org>
 */

#include <linux/module.h>
#include <linux/stddef.h>	/* for offsetof() */
#include <linux/init.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/utsname.h>
#include <linux/capability.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/in.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/reboot.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/ctype.h>
#include <linux/blkdev.h>
#include <linux/workqueue.h>
#include <linux/rcupdate.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/hardware.h>
#include <asm/param.h>		/* HZ */
#include <asm/led.h>
#include <asm/pdc.h>
#include <asm/uaccess.h>

/* The control of the LEDs and LCDs on PARISC-machines have to be done 
   completely in software. The necessary calculations are done in a work queue
   task which is scheduled regularly, and since the calculations may consume a 
   relatively large amount of CPU time, some of the calculations can be 
   turned off with the following variables (controlled via procfs) */

static int led_type __read_mostly = -1;
static unsigned char lastleds;	/* LED state from most recent update */
static unsigned int led_heartbeat __read_mostly = 1;
static unsigned int led_diskio    __read_mostly = 1;
static unsigned int led_lanrxtx   __read_mostly = 1;
static char lcd_text[32]          __read_mostly;
static char lcd_text_default[32]  __read_mostly;
static int  lcd_no_led_support    __read_mostly = 0; /* KittyHawk doesn't support LED on its LCD */


static struct workqueue_struct *led_wq;
static void led_work_func(struct work_struct *);
static DECLARE_DELAYED_WORK(led_task, led_work_func);

#if 0
#define DPRINTK(x)	printk x
#else
#define DPRINTK(x)
#endif

struct lcd_block {
	unsigned char command;	/* stores the command byte      */
	unsigned char on;	/* value for turning LED on     */
	unsigned char off;	/* value for turning LED off    */
};

/* Structure returned by PDC_RETURN_CHASSIS_INFO */
/* NOTE: we use unsigned long:16 two times, since the following member 
   lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
struct pdc_chassis_lcd_info_ret_block {
	unsigned long model:16;		/* DISPLAY_MODEL_XXXX */
	unsigned long lcd_width:16;	/* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
	unsigned long lcd_cmd_reg_addr;	/* ptr to LCD cmd-register & data ptr for LED */
	unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
	unsigned int min_cmd_delay;	/* delay in uS after cmd-write (LCD only) */
	unsigned char reset_cmd1;	/* command #1 for writing LCD string (LCD only) */
	unsigned char reset_cmd2;	/* command #2 for writing LCD string (LCD only) */
	unsigned char act_enable;	/* 0 = no activity (LCD only) */
	struct lcd_block heartbeat;
	struct lcd_block disk_io;
	struct lcd_block lan_rcv;
	struct lcd_block lan_tx;
	char _pad;
};


/* LCD_CMD and LCD_DATA for KittyHawk machines */
#define KITTYHAWK_LCD_CMD  F_EXTEND(0xf0190000UL) /* 64bit-ready */
#define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD+1)

/* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's 
 * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
static struct pdc_chassis_lcd_info_ret_block
lcd_info __attribute__((aligned(8))) __read_mostly =
{
	.model =		DISPLAY_MODEL_LCD,
	.lcd_width =		16,
	.lcd_cmd_reg_addr =	KITTYHAWK_LCD_CMD,
	.lcd_data_reg_addr =	KITTYHAWK_LCD_DATA,
	.min_cmd_delay =	80,
	.reset_cmd1 =		0x80,
	.reset_cmd2 =		0xc0,
};


/* direct access to some of the lcd_info variables */
#define LCD_CMD_REG	lcd_info.lcd_cmd_reg_addr	 
#define LCD_DATA_REG	lcd_info.lcd_data_reg_addr	 
#define LED_DATA_REG	lcd_info.lcd_cmd_reg_addr	/* LASI & ASP only */

#define LED_HASLCD 1
#define LED_NOLCD  0

/* The workqueue must be created at init-time */
static int start_task(void) 
{	
	/* Display the default text now */
	if (led_type == LED_HASLCD) lcd_print( lcd_text_default );

	/* KittyHawk has no LED support on its LCD */
	if (lcd_no_led_support) return 0;

	/* Create the work queue and queue the LED task */
	led_wq = create_singlethread_workqueue("led_wq");	
	queue_delayed_work(led_wq, &led_task, 0);

	return 0;
}

device_initcall(start_task);

/* ptr to LCD/LED-specific function */
static void (*led_func_ptr) (unsigned char) __read_mostly;

#ifdef CONFIG_PROC_FS
static int led_proc_show(struct seq_file *m, void *v)
{
	switch ((long)m->private)
	{
	case LED_NOLCD:
		seq_printf(m, "Heartbeat: %d\n", led_heartbeat);
		seq_printf(m, "Disk IO: %d\n", led_diskio);
		seq_printf(m, "LAN Rx/Tx: %d\n", led_lanrxtx);
		break;
	case LED_HASLCD:
		seq_printf(m, "%s\n", lcd_text);
		break;
	default:
		return 0;
	}
	return 0;
}

static int led_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, led_proc_show, PDE_DATA(inode));
}


static ssize_t led_proc_write(struct file *file, const char *buf,
	size_t count, loff_t *pos)
{
	void *data = PDE_DATA(file_inode(file));
	char *cur, lbuf[32];
	int d;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	if (count >= sizeof(lbuf))
		count = sizeof(lbuf)-1;

	if (copy_from_user(lbuf, buf, count))
		return -EFAULT;
	lbuf[count] = 0;

	cur = lbuf;

	switch ((long)data)
	{
	case LED_NOLCD:
		d = *cur++ - '0';
		if (d != 0 && d != 1) goto parse_error;
		led_heartbeat = d;

		if (*cur++ != ' ') goto parse_error;

		d = *cur++ - '0';
		if (d != 0 && d != 1) goto parse_error;
		led_diskio = d;

		if (*cur++ != ' ') goto parse_error;

		d = *cur++ - '0';
		if (d != 0 && d != 1) goto parse_error;
		led_lanrxtx = d;

		break;
	case LED_HASLCD:
		if (*cur && cur[strlen(cur)-1] == '\n')
			cur[strlen(cur)-1] = 0;
		if (*cur == 0) 
			cur = lcd_text_default;
		lcd_print(cur);
		break;
	default:
		return 0;
	}
	
	return count;

parse_error:
	if ((long)data == LED_NOLCD)
		printk(KERN_CRIT "Parse error: expect \"n n n\" (n == 0 or 1) for heartbeat,\ndisk io and lan tx/rx indicators\n");
	return -EINVAL;
}

static const struct file_operations led_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= led_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= led_proc_write,
};

static int __init led_create_procfs(void)
{
	struct proc_dir_entry *proc_pdc_root = NULL;
	struct proc_dir_entry *ent;

	if (led_type == -1) return -1;

	proc_pdc_root = proc_mkdir("pdc", 0);
	if (!proc_pdc_root) return -1;

	if (!lcd_no_led_support)
	{
		ent = proc_create_data("led", S_IRUGO|S_IWUSR, proc_pdc_root,
					&led_proc_fops, (void *)LED_NOLCD); /* LED */
		if (!ent) return -1;
	}

	if (led_type == LED_HASLCD)
	{
		ent = proc_create_data("lcd", S_IRUGO|S_IWUSR, proc_pdc_root,
					&led_proc_fops, (void *)LED_HASLCD); /* LCD */
		if (!ent) return -1;
	}

	return 0;
}
#endif

/*
   ** 
   ** led_ASP_driver()
   ** 
 */
#define	LED_DATA	0x01	/* data to shift (0:on 1:off) */
#define	LED_STROBE	0x02	/* strobe to clock data */
static void led_ASP_driver(unsigned char leds)
{
	int i;

	leds = ~leds;
	for (i = 0; i < 8; i++) {
		unsigned char value;
		value = (leds & 0x80) >> 7;
		gsc_writeb( value,		 LED_DATA_REG );
		gsc_writeb( value | LED_STROBE,	 LED_DATA_REG );
		leds <<= 1;
	}
}


/*
   ** 
   ** led_LASI_driver()
   ** 
 */
static void led_LASI_driver(unsigned char leds)
{
	leds = ~leds;
	gsc_writeb( leds, LED_DATA_REG );
}


/*
   ** 
   ** led_LCD_driver()
   **   
 */
static void led_LCD_driver(unsigned char leds)
{
	static int i;
	static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
		LED_LAN_RCV, LED_LAN_TX };
	
	static struct lcd_block * blockp[4] = {
		&lcd_info.heartbeat,
		&lcd_info.disk_io,
		&lcd_info.lan_rcv,
		&lcd_info.lan_tx
	};

	/* Convert min_cmd_delay to milliseconds */
	unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
	
	for (i=0; i<4; ++i) 
	{
		if ((leds & mask[i]) != (lastleds & mask[i])) 
		{
			gsc_writeb( blockp[i]->command, LCD_CMD_REG );
			msleep(msec_cmd_delay);
			
			gsc_writeb( leds & mask[i] ? blockp[i]->on : 
					blockp[i]->off, LCD_DATA_REG );
			msleep(msec_cmd_delay);
		}
	}
}


/*
   ** 
   ** led_get_net_activity()
   ** 
   ** calculate if there was TX- or RX-throughput on the network interfaces
   ** (analog to dev_get_info() from net/core/dev.c)
   **   
 */
static __inline__ int led_get_net_activity(void)
{ 
#ifndef CONFIG_NET
	return 0;
#else
	static u64 rx_total_last, tx_total_last;
	u64 rx_total, tx_total;
	struct net_device *dev;
	int retval;

	rx_total = tx_total = 0;
	
	/* we are running as a workqueue task, so we can use an RCU lookup */
	rcu_read_lock();
	for_each_netdev_rcu(&init_net, dev) {
	    const struct rtnl_link_stats64 *stats;
	    struct rtnl_link_stats64 temp;
	    struct in_device *in_dev = __in_dev_get_rcu(dev);
	    if (!in_dev || !in_dev->ifa_list)
		continue;
	    if (ipv4_is_loopback(in_dev->ifa_list->ifa_local))
		continue;
	    stats = dev_get_stats(dev, &temp);
	    rx_total += stats->rx_packets;
	    tx_total += stats->tx_packets;
	}
	rcu_read_unlock();

	retval = 0;

	if (rx_total != rx_total_last) {
		rx_total_last = rx_total;
		retval |= LED_LAN_RCV;
	}

	if (tx_total != tx_total_last) {
		tx_total_last = tx_total;
		retval |= LED_LAN_TX;
	}

	return retval;
#endif
}


/*
   ** 
   ** led_get_diskio_activity()
   ** 
   ** calculate if there was disk-io in the system
   **   
 */
static __inline__ int led_get_diskio_activity(void)
{	
	static unsigned long last_pgpgin, last_pgpgout;
	unsigned long events[NR_VM_EVENT_ITEMS];
	int changed;

	all_vm_events(events);

	/* Just use a very simple calculation here. Do not care about overflow,
	   since we only want to know if there was activity or not. */
	changed = (events[PGPGIN] != last_pgpgin) ||
		  (events[PGPGOUT] != last_pgpgout);
	last_pgpgin  = events[PGPGIN];
	last_pgpgout = events[PGPGOUT];

	return (changed ? LED_DISK_IO : 0);
}



/*
   ** led_work_func()
   ** 
   ** manages when and which chassis LCD/LED gets updated

    TODO:
    - display load average (older machines like 715/64 have 4 "free" LED's for that)
    - optimizations
 */

#define HEARTBEAT_LEN (HZ*10/100)
#define HEARTBEAT_2ND_RANGE_START (HZ*28/100)
#define HEARTBEAT_2ND_RANGE_END   (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)

#define LED_UPDATE_INTERVAL (1 + (HZ*19/1000))

static void led_work_func (struct work_struct *unused)
{
	static unsigned long last_jiffies;
	static unsigned long count_HZ; /* counter in range 0..HZ */
	unsigned char currentleds = 0; /* stores current value of the LEDs */

	/* exit if not initialized */
	if (!led_func_ptr)
	    return;

	/* increment the heartbeat timekeeper */
	count_HZ += jiffies - last_jiffies;
	last_jiffies = jiffies;
	if (count_HZ >= HZ)
	    count_HZ = 0;

	if (likely(led_heartbeat))
	{
		/* flash heartbeat-LED like a real heart
		 * (2 x short then a long delay)
		 */
		if (count_HZ < HEARTBEAT_LEN || 
				(count_HZ >= HEARTBEAT_2ND_RANGE_START &&
				count_HZ < HEARTBEAT_2ND_RANGE_END)) 
			currentleds |= LED_HEARTBEAT;
	}

	if (likely(led_lanrxtx))  currentleds |= led_get_net_activity();
	if (likely(led_diskio))   currentleds |= led_get_diskio_activity();

	/* blink LEDs if we got an Oops (HPMC) */
	if (unlikely(oops_in_progress)) {
		if (boot_cpu_data.cpu_type >= pcxl2) {
			/* newer machines don't have loadavg. LEDs, so we
			 * let all LEDs blink twice per second instead */
			currentleds = (count_HZ <= (HZ/2)) ? 0 : 0xff;
		} else {
			/* old machines: blink loadavg. LEDs twice per second */
			if (count_HZ <= (HZ/2))
				currentleds &= ~(LED4|LED5|LED6|LED7);
			else
				currentleds |= (LED4|LED5|LED6|LED7);
		}
	}

	if (currentleds != lastleds)
	{
		led_func_ptr(currentleds);	/* Update the LCD/LEDs */
		lastleds = currentleds;
	}

	queue_delayed_work(led_wq, &led_task, LED_UPDATE_INTERVAL);
}

/*
   ** led_halt()
   ** 
   ** called by the reboot notifier chain at shutdown and stops all
   ** LED/LCD activities.
   ** 
 */

static int led_halt(struct notifier_block *, unsigned long, void *);

static struct notifier_block led_notifier = {
	.notifier_call = led_halt,
};
static int notifier_disabled = 0;

static int led_halt(struct notifier_block *nb, unsigned long event, void *buf) 
{
	char *txt;

	if (notifier_disabled)
		return NOTIFY_OK;

	notifier_disabled = 1;
	switch (event) {
	case SYS_RESTART:	txt = "SYSTEM RESTART";
				break;
	case SYS_HALT:		txt = "SYSTEM HALT";
				break;
	case SYS_POWER_OFF:	txt = "SYSTEM POWER OFF";
				break;
	default:		return NOTIFY_DONE;
	}
	
	/* Cancel the work item and delete the queue */
	if (led_wq) {
		cancel_delayed_work_sync(&led_task);
		destroy_workqueue(led_wq);
		led_wq = NULL;
	}
 
	if (lcd_info.model == DISPLAY_MODEL_LCD)
		lcd_print(txt);
	else
		if (led_func_ptr)
			led_func_ptr(0xff); /* turn all LEDs ON */
	
	return NOTIFY_OK;
}

/*
   ** register_led_driver()
   ** 
   ** registers an external LED or LCD for usage by this driver.
   ** currently only LCD-, LASI- and ASP-style LCD/LED's are supported.
   ** 
 */

int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
{
	static int initialized;
	
	if (initialized || !data_reg)
		return 1;
	
	lcd_info.model = model;		/* store the values */
	LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;

	switch (lcd_info.model) {
	case DISPLAY_MODEL_LCD:
		LCD_DATA_REG = data_reg;
		printk(KERN_INFO "LCD display at %lx,%lx registered\n", 
			LCD_CMD_REG , LCD_DATA_REG);
		led_func_ptr = led_LCD_driver;
		led_type = LED_HASLCD;
		break;

	case DISPLAY_MODEL_LASI:
		LED_DATA_REG = data_reg;
		led_func_ptr = led_LASI_driver;
		printk(KERN_INFO "LED display at %lx registered\n", LED_DATA_REG);
		led_type = LED_NOLCD;
		break;

	case DISPLAY_MODEL_OLD_ASP:
		LED_DATA_REG = data_reg;
		led_func_ptr = led_ASP_driver;
		printk(KERN_INFO "LED (ASP-style) display at %lx registered\n", 
		    LED_DATA_REG);
		led_type = LED_NOLCD;
		break;

	default:
		printk(KERN_ERR "%s: Wrong LCD/LED model %d !\n",
		       __func__, lcd_info.model);
		return 1;
	}
	
	/* mark the LCD/LED driver now as initialized and 
	 * register to the reboot notifier chain */
	initialized++;
	register_reboot_notifier(&led_notifier);

	/* Ensure the work is queued */
	if (led_wq) {
		queue_delayed_work(led_wq, &led_task, 0);
	}

	return 0;
}

/*
   ** register_led_regions()
   ** 
   ** register_led_regions() registers the LCD/LED regions for /procfs.
   ** At bootup - where the initialisation of the LCD/LED normally happens - 
   ** not all internal structures of request_region() are properly set up,
   ** so that we delay the led-registration until after busdevices_init() 
   ** has been executed.
   **
 */

void __init register_led_regions(void)
{
	switch (lcd_info.model) {
	case DISPLAY_MODEL_LCD:
		request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
		request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
		break;
	case DISPLAY_MODEL_LASI:
	case DISPLAY_MODEL_OLD_ASP:
		request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
		break;
	}
}


/*
   ** 
   ** lcd_print()
   ** 
   ** Displays the given string on the LCD-Display of newer machines.
   ** lcd_print() disables/enables the timer-based led work queue to
   ** avoid a race condition while writing the CMD/DATA register pair.
   **
 */
int lcd_print( const char *str )
{
	int i;

	if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
	    return 0;
	
	/* temporarily disable the led work task */
	if (led_wq)
		cancel_delayed_work_sync(&led_task);

	/* copy display string to buffer for procfs */
	strlcpy(lcd_text, str, sizeof(lcd_text));

	/* Set LCD Cursor to 1st character */
	gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
	udelay(lcd_info.min_cmd_delay);

	/* Print the string */
	for (i=0; i < lcd_info.lcd_width; i++) {
	    if (str && *str)
		gsc_writeb(*str++, LCD_DATA_REG);
	    else
		gsc_writeb(' ', LCD_DATA_REG);
	    udelay(lcd_info.min_cmd_delay);
	}
	
	/* re-queue the work */
	if (led_wq) {
		queue_delayed_work(led_wq, &led_task, 0);
	}

	return lcd_info.lcd_width;
}

/*
   ** led_init()
   ** 
   ** led_init() is called very early in the bootup-process from setup.c 
   ** and asks the PDC for an usable chassis LCD or LED.
   ** If the PDC doesn't return any info, then the LED
   ** is detected by lasi.c or asp.c and registered with the
   ** above functions lasi_led_init() or asp_led_init().
   ** KittyHawk machines have often a buggy PDC, so that
   ** we explicitly check for those machines here.
 */

int __init led_init(void)
{
	struct pdc_chassis_info chassis_info;
	int ret;

	snprintf(lcd_text_default, sizeof(lcd_text_default),
		"Linux %s", init_utsname()->release);

	/* Work around the buggy PDC of KittyHawk-machines */
	switch (CPU_HVERSION) {
	case 0x580:		/* KittyHawk DC2-100 (K100) */
	case 0x581:		/* KittyHawk DC3-120 (K210) */
	case 0x582:		/* KittyHawk DC3 100 (K400) */
	case 0x583:		/* KittyHawk DC3 120 (K410) */
	case 0x58B:		/* KittyHawk DC2 100 (K200) */
		printk(KERN_INFO "%s: KittyHawk-Machine (hversion 0x%x) found, "
				"LED detection skipped.\n", __FILE__, CPU_HVERSION);
		lcd_no_led_support = 1;
		goto found;	/* use the preinitialized values of lcd_info */
	}

	/* initialize the struct, so that we can check for valid return values */
	lcd_info.model = DISPLAY_MODEL_NONE;
	chassis_info.actcnt = chassis_info.maxcnt = 0;

	ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
	if (ret == PDC_OK) {
		DPRINTK((KERN_INFO "%s: chassis info: model=%d (%s), "
			 "lcd_width=%d, cmd_delay=%u,\n"
			 "%s: sizecnt=%d, actcnt=%ld, maxcnt=%ld\n",
		         __FILE__, lcd_info.model,
			 (lcd_info.model==DISPLAY_MODEL_LCD) ? "LCD" :
			  (lcd_info.model==DISPLAY_MODEL_LASI) ? "LED" : "unknown",
			 lcd_info.lcd_width, lcd_info.min_cmd_delay,
			 __FILE__, sizeof(lcd_info), 
			 chassis_info.actcnt, chassis_info.maxcnt));
		DPRINTK((KERN_INFO "%s: cmd=%p, data=%p, reset1=%x, reset2=%x, act_enable=%d\n",
			__FILE__, lcd_info.lcd_cmd_reg_addr, 
			lcd_info.lcd_data_reg_addr, lcd_info.reset_cmd1,  
			lcd_info.reset_cmd2, lcd_info.act_enable ));
	
		/* check the results. Some machines have a buggy PDC */
		if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
			goto not_found;

		switch (lcd_info.model) {
		case DISPLAY_MODEL_LCD:		/* LCD display */
			if (chassis_info.actcnt < 
				offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
				goto not_found;
			if (!lcd_info.act_enable) {
				DPRINTK((KERN_INFO "PDC prohibited usage of the LCD.\n"));
				goto not_found;
			}
			break;

		case DISPLAY_MODEL_NONE:	/* no LED or LCD available */
			printk(KERN_INFO "PDC reported no LCD or LED.\n");
			goto not_found;

		case DISPLAY_MODEL_LASI:	/* Lasi style 8 bit LED display */
			if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
				goto not_found;
			break;

		default:
			printk(KERN_WARNING "PDC reported unknown LCD/LED model %d\n",
			       lcd_info.model);
			goto not_found;
		} /* switch() */

found:
		/* register the LCD/LED driver */
		register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
		return 0;

	} else { /* if() */
		DPRINTK((KERN_INFO "pdc_chassis_info call failed with retval = %d\n", ret));
	}

not_found:
	lcd_info.model = DISPLAY_MODEL_NONE;
	return 1;
}

static void __exit led_exit(void)
{
	unregister_reboot_notifier(&led_notifier);
	return;
}

#ifdef CONFIG_PROC_FS
module_init(led_create_procfs)
#endif