linux/drivers/parisc/led.c
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   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
  60static int led_type __read_mostly = -1;
  61static unsigned char lastleds;  /* LED state from most recent update */
  62static unsigned int led_heartbeat __read_mostly = 1;
  63static unsigned int led_diskio    __read_mostly = 1;
  64static unsigned int led_lanrxtx   __read_mostly = 1;
  65static char lcd_text[32]          __read_mostly;
  66static char lcd_text_default[32]  __read_mostly;
  67
  68
  69static struct workqueue_struct *led_wq;
  70static void led_work_func(struct work_struct *);
  71static DECLARE_DELAYED_WORK(led_task, led_work_func);
  72
  73#if 0
  74#define DPRINTK(x)      printk x
  75#else
  76#define DPRINTK(x)
  77#endif
  78
  79struct lcd_block {
  80        unsigned char command;  /* stores the command byte      */
  81        unsigned char on;       /* value for turning LED on     */
  82        unsigned char off;      /* value for turning LED off    */
  83};
  84
  85/* Structure returned by PDC_RETURN_CHASSIS_INFO */
  86/* NOTE: we use unsigned long:16 two times, since the following member 
  87   lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
  88struct pdc_chassis_lcd_info_ret_block {
  89        unsigned long model:16;         /* DISPLAY_MODEL_XXXX */
  90        unsigned long lcd_width:16;     /* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
  91        unsigned long lcd_cmd_reg_addr; /* ptr to LCD cmd-register & data ptr for LED */
  92        unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
  93        unsigned int min_cmd_delay;     /* delay in uS after cmd-write (LCD only) */
  94        unsigned char reset_cmd1;       /* command #1 for writing LCD string (LCD only) */
  95        unsigned char reset_cmd2;       /* command #2 for writing LCD string (LCD only) */
  96        unsigned char act_enable;       /* 0 = no activity (LCD only) */
  97        struct lcd_block heartbeat;
  98        struct lcd_block disk_io;
  99        struct lcd_block lan_rcv;
 100        struct lcd_block lan_tx;
 101        char _pad;
 102};
 103
 104
 105/* LCD_CMD and LCD_DATA for KittyHawk machines */
 106#define KITTYHAWK_LCD_CMD  F_EXTEND(0xf0190000UL) /* 64bit-ready */
 107#define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD+1)
 108
 109/* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's 
 110 * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
 111static struct pdc_chassis_lcd_info_ret_block
 112lcd_info __attribute__((aligned(8))) __read_mostly =
 113{
 114        .model =                DISPLAY_MODEL_LCD,
 115        .lcd_width =            16,
 116        .lcd_cmd_reg_addr =     KITTYHAWK_LCD_CMD,
 117        .lcd_data_reg_addr =    KITTYHAWK_LCD_DATA,
 118        .min_cmd_delay =        40,
 119        .reset_cmd1 =           0x80,
 120        .reset_cmd2 =           0xc0,
 121};
 122
 123
 124/* direct access to some of the lcd_info variables */
 125#define LCD_CMD_REG     lcd_info.lcd_cmd_reg_addr        
 126#define LCD_DATA_REG    lcd_info.lcd_data_reg_addr       
 127#define LED_DATA_REG    lcd_info.lcd_cmd_reg_addr       /* LASI & ASP only */
 128
 129#define LED_HASLCD 1
 130#define LED_NOLCD  0
 131
 132/* The workqueue must be created at init-time */
 133static int start_task(void) 
 134{       
 135        /* Display the default text now */
 136        if (led_type == LED_HASLCD) lcd_print( lcd_text_default );
 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
 145device_initcall(start_task);
 146
 147/* ptr to LCD/LED-specific function */
 148static void (*led_func_ptr) (unsigned char) __read_mostly;
 149
 150#ifdef CONFIG_PROC_FS
 151static 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
 169static int led_proc_open(struct inode *inode, struct file *file)
 170{
 171        return single_open(file, led_proc_show, PDE(inode)->data);
 172}
 173
 174
 175static ssize_t led_proc_write(struct file *file, const char *buf,
 176        size_t count, loff_t *pos)
 177{
 178        void *data = PDE(file->f_path.dentry->d_inode)->data;
 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
 227parse_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
 233static 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
 242static 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", 0);
 250        if (!proc_pdc_root) return -1;
 251        ent = proc_create_data("led", S_IRUGO|S_IWUSR, proc_pdc_root,
 252                                &led_proc_fops, (void *)LED_NOLCD); /* LED */
 253        if (!ent) return -1;
 254
 255        if (led_type == LED_HASLCD)
 256        {
 257                ent = proc_create_data("lcd", S_IRUGO|S_IWUSR, proc_pdc_root,
 258                                        &led_proc_fops, (void *)LED_HASLCD); /* LCD */
 259                if (!ent) return -1;
 260        }
 261
 262        return 0;
 263}
 264#endif
 265
 266/*
 267   ** 
 268   ** led_ASP_driver()
 269   ** 
 270 */
 271#define LED_DATA        0x01    /* data to shift (0:on 1:off) */
 272#define LED_STROBE      0x02    /* strobe to clock data */
 273static void led_ASP_driver(unsigned char leds)
 274{
 275        int i;
 276
 277        leds = ~leds;
 278        for (i = 0; i < 8; i++) {
 279                unsigned char value;
 280                value = (leds & 0x80) >> 7;
 281                gsc_writeb( value,               LED_DATA_REG );
 282                gsc_writeb( value | LED_STROBE,  LED_DATA_REG );
 283                leds <<= 1;
 284        }
 285}
 286
 287
 288/*
 289   ** 
 290   ** led_LASI_driver()
 291   ** 
 292 */
 293static void led_LASI_driver(unsigned char leds)
 294{
 295        leds = ~leds;
 296        gsc_writeb( leds, LED_DATA_REG );
 297}
 298
 299
 300/*
 301   ** 
 302   ** led_LCD_driver()
 303   **   
 304 */
 305static void led_LCD_driver(unsigned char leds)
 306{
 307        static int i;
 308        static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
 309                LED_LAN_RCV, LED_LAN_TX };
 310        
 311        static struct lcd_block * blockp[4] = {
 312                &lcd_info.heartbeat,
 313                &lcd_info.disk_io,
 314                &lcd_info.lan_rcv,
 315                &lcd_info.lan_tx
 316        };
 317
 318        /* Convert min_cmd_delay to milliseconds */
 319        unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
 320        
 321        for (i=0; i<4; ++i) 
 322        {
 323                if ((leds & mask[i]) != (lastleds & mask[i])) 
 324                {
 325                        gsc_writeb( blockp[i]->command, LCD_CMD_REG );
 326                        msleep(msec_cmd_delay);
 327                        
 328                        gsc_writeb( leds & mask[i] ? blockp[i]->on : 
 329                                        blockp[i]->off, LCD_DATA_REG );
 330                        msleep(msec_cmd_delay);
 331                }
 332        }
 333}
 334
 335
 336/*
 337   ** 
 338   ** led_get_net_activity()
 339   ** 
 340   ** calculate if there was TX- or RX-throughput on the network interfaces
 341   ** (analog to dev_get_info() from net/core/dev.c)
 342   **   
 343 */
 344static __inline__ int led_get_net_activity(void)
 345{ 
 346#ifndef CONFIG_NET
 347        return 0;
 348#else
 349        static unsigned long rx_total_last, tx_total_last;
 350        unsigned long rx_total, tx_total;
 351        struct net_device *dev;
 352        int retval;
 353
 354        rx_total = tx_total = 0;
 355        
 356        /* we are running as a workqueue task, so we can use an RCU lookup */
 357        rcu_read_lock();
 358        for_each_netdev_rcu(&init_net, dev) {
 359            const struct net_device_stats *stats;
 360            struct rtnl_link_stats64 temp;
 361            struct in_device *in_dev = __in_dev_get_rcu(dev);
 362            if (!in_dev || !in_dev->ifa_list)
 363                continue;
 364            if (ipv4_is_loopback(in_dev->ifa_list->ifa_local))
 365                continue;
 366            stats = dev_get_stats(dev, &temp);
 367            rx_total += stats->rx_packets;
 368            tx_total += stats->tx_packets;
 369        }
 370        rcu_read_unlock();
 371
 372        retval = 0;
 373
 374        if (rx_total != rx_total_last) {
 375                rx_total_last = rx_total;
 376                retval |= LED_LAN_RCV;
 377        }
 378
 379        if (tx_total != tx_total_last) {
 380                tx_total_last = tx_total;
 381                retval |= LED_LAN_TX;
 382        }
 383
 384        return retval;
 385#endif
 386}
 387
 388
 389/*
 390   ** 
 391   ** led_get_diskio_activity()
 392   ** 
 393   ** calculate if there was disk-io in the system
 394   **   
 395 */
 396static __inline__ int led_get_diskio_activity(void)
 397{       
 398        static unsigned long last_pgpgin, last_pgpgout;
 399        unsigned long events[NR_VM_EVENT_ITEMS];
 400        int changed;
 401
 402        all_vm_events(events);
 403
 404        /* Just use a very simple calculation here. Do not care about overflow,
 405           since we only want to know if there was activity or not. */
 406        changed = (events[PGPGIN] != last_pgpgin) ||
 407                  (events[PGPGOUT] != last_pgpgout);
 408        last_pgpgin  = events[PGPGIN];
 409        last_pgpgout = events[PGPGOUT];
 410
 411        return (changed ? LED_DISK_IO : 0);
 412}
 413
 414
 415
 416/*
 417   ** led_work_func()
 418   ** 
 419   ** manages when and which chassis LCD/LED gets updated
 420
 421    TODO:
 422    - display load average (older machines like 715/64 have 4 "free" LED's for that)
 423    - optimizations
 424 */
 425
 426#define HEARTBEAT_LEN (HZ*10/100)
 427#define HEARTBEAT_2ND_RANGE_START (HZ*28/100)
 428#define HEARTBEAT_2ND_RANGE_END   (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)
 429
 430#define LED_UPDATE_INTERVAL (1 + (HZ*19/1000))
 431
 432static void led_work_func (struct work_struct *unused)
 433{
 434        static unsigned long last_jiffies;
 435        static unsigned long count_HZ; /* counter in range 0..HZ */
 436        unsigned char currentleds = 0; /* stores current value of the LEDs */
 437
 438        /* exit if not initialized */
 439        if (!led_func_ptr)
 440            return;
 441
 442        /* increment the heartbeat timekeeper */
 443        count_HZ += jiffies - last_jiffies;
 444        last_jiffies = jiffies;
 445        if (count_HZ >= HZ)
 446            count_HZ = 0;
 447
 448        if (likely(led_heartbeat))
 449        {
 450                /* flash heartbeat-LED like a real heart
 451                 * (2 x short then a long delay)
 452                 */
 453                if (count_HZ < HEARTBEAT_LEN || 
 454                                (count_HZ >= HEARTBEAT_2ND_RANGE_START &&
 455                                count_HZ < HEARTBEAT_2ND_RANGE_END)) 
 456                        currentleds |= LED_HEARTBEAT;
 457        }
 458
 459        if (likely(led_lanrxtx))  currentleds |= led_get_net_activity();
 460        if (likely(led_diskio))   currentleds |= led_get_diskio_activity();
 461
 462        /* blink LEDs if we got an Oops (HPMC) */
 463        if (unlikely(oops_in_progress)) {
 464                if (boot_cpu_data.cpu_type >= pcxl2) {
 465                        /* newer machines don't have loadavg. LEDs, so we
 466                         * let all LEDs blink twice per second instead */
 467                        currentleds = (count_HZ <= (HZ/2)) ? 0 : 0xff;
 468                } else {
 469                        /* old machines: blink loadavg. LEDs twice per second */
 470                        if (count_HZ <= (HZ/2))
 471                                currentleds &= ~(LED4|LED5|LED6|LED7);
 472                        else
 473                                currentleds |= (LED4|LED5|LED6|LED7);
 474                }
 475        }
 476
 477        if (currentleds != lastleds)
 478        {
 479                led_func_ptr(currentleds);      /* Update the LCD/LEDs */
 480                lastleds = currentleds;
 481        }
 482
 483        queue_delayed_work(led_wq, &led_task, LED_UPDATE_INTERVAL);
 484}
 485
 486/*
 487   ** led_halt()
 488   ** 
 489   ** called by the reboot notifier chain at shutdown and stops all
 490   ** LED/LCD activities.
 491   ** 
 492 */
 493
 494static int led_halt(struct notifier_block *, unsigned long, void *);
 495
 496static struct notifier_block led_notifier = {
 497        .notifier_call = led_halt,
 498};
 499static int notifier_disabled = 0;
 500
 501static int led_halt(struct notifier_block *nb, unsigned long event, void *buf) 
 502{
 503        char *txt;
 504
 505        if (notifier_disabled)
 506                return NOTIFY_OK;
 507
 508        notifier_disabled = 1;
 509        switch (event) {
 510        case SYS_RESTART:       txt = "SYSTEM RESTART";
 511                                break;
 512        case SYS_HALT:          txt = "SYSTEM HALT";
 513                                break;
 514        case SYS_POWER_OFF:     txt = "SYSTEM POWER OFF";
 515                                break;
 516        default:                return NOTIFY_DONE;
 517        }
 518        
 519        /* Cancel the work item and delete the queue */
 520        if (led_wq) {
 521                cancel_delayed_work_sync(&led_task);
 522                destroy_workqueue(led_wq);
 523                led_wq = NULL;
 524        }
 525 
 526        if (lcd_info.model == DISPLAY_MODEL_LCD)
 527                lcd_print(txt);
 528        else
 529                if (led_func_ptr)
 530                        led_func_ptr(0xff); /* turn all LEDs ON */
 531        
 532        return NOTIFY_OK;
 533}
 534
 535/*
 536   ** register_led_driver()
 537   ** 
 538   ** registers an external LED or LCD for usage by this driver.
 539   ** currently only LCD-, LASI- and ASP-style LCD/LED's are supported.
 540   ** 
 541 */
 542
 543int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
 544{
 545        static int initialized;
 546        
 547        if (initialized || !data_reg)
 548                return 1;
 549        
 550        lcd_info.model = model;         /* store the values */
 551        LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;
 552
 553        switch (lcd_info.model) {
 554        case DISPLAY_MODEL_LCD:
 555                LCD_DATA_REG = data_reg;
 556                printk(KERN_INFO "LCD display at %lx,%lx registered\n", 
 557                        LCD_CMD_REG , LCD_DATA_REG);
 558                led_func_ptr = led_LCD_driver;
 559                led_type = LED_HASLCD;
 560                break;
 561
 562        case DISPLAY_MODEL_LASI:
 563                LED_DATA_REG = data_reg;
 564                led_func_ptr = led_LASI_driver;
 565                printk(KERN_INFO "LED display at %lx registered\n", LED_DATA_REG);
 566                led_type = LED_NOLCD;
 567                break;
 568
 569        case DISPLAY_MODEL_OLD_ASP:
 570                LED_DATA_REG = data_reg;
 571                led_func_ptr = led_ASP_driver;
 572                printk(KERN_INFO "LED (ASP-style) display at %lx registered\n", 
 573                    LED_DATA_REG);
 574                led_type = LED_NOLCD;
 575                break;
 576
 577        default:
 578                printk(KERN_ERR "%s: Wrong LCD/LED model %d !\n",
 579                       __func__, lcd_info.model);
 580                return 1;
 581        }
 582        
 583        /* mark the LCD/LED driver now as initialized and 
 584         * register to the reboot notifier chain */
 585        initialized++;
 586        register_reboot_notifier(&led_notifier);
 587
 588        /* Ensure the work is queued */
 589        if (led_wq) {
 590                queue_delayed_work(led_wq, &led_task, 0);
 591        }
 592
 593        return 0;
 594}
 595
 596/*
 597   ** register_led_regions()
 598   ** 
 599   ** register_led_regions() registers the LCD/LED regions for /procfs.
 600   ** At bootup - where the initialisation of the LCD/LED normally happens - 
 601   ** not all internal structures of request_region() are properly set up,
 602   ** so that we delay the led-registration until after busdevices_init() 
 603   ** has been executed.
 604   **
 605 */
 606
 607void __init register_led_regions(void)
 608{
 609        switch (lcd_info.model) {
 610        case DISPLAY_MODEL_LCD:
 611                request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
 612                request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
 613                break;
 614        case DISPLAY_MODEL_LASI:
 615        case DISPLAY_MODEL_OLD_ASP:
 616                request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
 617                break;
 618        }
 619}
 620
 621
 622/*
 623   ** 
 624   ** lcd_print()
 625   ** 
 626   ** Displays the given string on the LCD-Display of newer machines.
 627   ** lcd_print() disables/enables the timer-based led work queue to
 628   ** avoid a race condition while writing the CMD/DATA register pair.
 629   **
 630 */
 631int lcd_print( const char *str )
 632{
 633        int i;
 634
 635        if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
 636            return 0;
 637        
 638        /* temporarily disable the led work task */
 639        if (led_wq)
 640                cancel_delayed_work_sync(&led_task);
 641
 642        /* copy display string to buffer for procfs */
 643        strlcpy(lcd_text, str, sizeof(lcd_text));
 644
 645        /* Set LCD Cursor to 1st character */
 646        gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
 647        udelay(lcd_info.min_cmd_delay);
 648
 649        /* Print the string */
 650        for (i=0; i < lcd_info.lcd_width; i++) {
 651            if (str && *str)
 652                gsc_writeb(*str++, LCD_DATA_REG);
 653            else
 654                gsc_writeb(' ', LCD_DATA_REG);
 655            udelay(lcd_info.min_cmd_delay);
 656        }
 657        
 658        /* re-queue the work */
 659        if (led_wq) {
 660                queue_delayed_work(led_wq, &led_task, 0);
 661        }
 662
 663        return lcd_info.lcd_width;
 664}
 665
 666/*
 667   ** led_init()
 668   ** 
 669   ** led_init() is called very early in the bootup-process from setup.c 
 670   ** and asks the PDC for an usable chassis LCD or LED.
 671   ** If the PDC doesn't return any info, then the LED
 672   ** is detected by lasi.c or asp.c and registered with the
 673   ** above functions lasi_led_init() or asp_led_init().
 674   ** KittyHawk machines have often a buggy PDC, so that
 675   ** we explicitly check for those machines here.
 676 */
 677
 678int __init led_init(void)
 679{
 680        struct pdc_chassis_info chassis_info;
 681        int ret;
 682
 683        snprintf(lcd_text_default, sizeof(lcd_text_default),
 684                "Linux %s", init_utsname()->release);
 685
 686        /* Work around the buggy PDC of KittyHawk-machines */
 687        switch (CPU_HVERSION) {
 688        case 0x580:             /* KittyHawk DC2-100 (K100) */
 689        case 0x581:             /* KittyHawk DC3-120 (K210) */
 690        case 0x582:             /* KittyHawk DC3 100 (K400) */
 691        case 0x583:             /* KittyHawk DC3 120 (K410) */
 692        case 0x58B:             /* KittyHawk DC2 100 (K200) */
 693                printk(KERN_INFO "%s: KittyHawk-Machine (hversion 0x%x) found, "
 694                                "LED detection skipped.\n", __FILE__, CPU_HVERSION);
 695                goto found;     /* use the preinitialized values of lcd_info */
 696        }
 697
 698        /* initialize the struct, so that we can check for valid return values */
 699        lcd_info.model = DISPLAY_MODEL_NONE;
 700        chassis_info.actcnt = chassis_info.maxcnt = 0;
 701
 702        ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
 703        if (ret == PDC_OK) {
 704                DPRINTK((KERN_INFO "%s: chassis info: model=%d (%s), "
 705                         "lcd_width=%d, cmd_delay=%u,\n"
 706                         "%s: sizecnt=%d, actcnt=%ld, maxcnt=%ld\n",
 707                         __FILE__, lcd_info.model,
 708                         (lcd_info.model==DISPLAY_MODEL_LCD) ? "LCD" :
 709                          (lcd_info.model==DISPLAY_MODEL_LASI) ? "LED" : "unknown",
 710                         lcd_info.lcd_width, lcd_info.min_cmd_delay,
 711                         __FILE__, sizeof(lcd_info), 
 712                         chassis_info.actcnt, chassis_info.maxcnt));
 713                DPRINTK((KERN_INFO "%s: cmd=%p, data=%p, reset1=%x, reset2=%x, act_enable=%d\n",
 714                        __FILE__, lcd_info.lcd_cmd_reg_addr, 
 715                        lcd_info.lcd_data_reg_addr, lcd_info.reset_cmd1,  
 716                        lcd_info.reset_cmd2, lcd_info.act_enable ));
 717        
 718                /* check the results. Some machines have a buggy PDC */
 719                if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
 720                        goto not_found;
 721
 722                switch (lcd_info.model) {
 723                case DISPLAY_MODEL_LCD:         /* LCD display */
 724                        if (chassis_info.actcnt < 
 725                                offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
 726                                goto not_found;
 727                        if (!lcd_info.act_enable) {
 728                                DPRINTK((KERN_INFO "PDC prohibited usage of the LCD.\n"));
 729                                goto not_found;
 730                        }
 731                        break;
 732
 733                case DISPLAY_MODEL_NONE:        /* no LED or LCD available */
 734                        printk(KERN_INFO "PDC reported no LCD or LED.\n");
 735                        goto not_found;
 736
 737                case DISPLAY_MODEL_LASI:        /* Lasi style 8 bit LED display */
 738                        if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
 739                                goto not_found;
 740                        break;
 741
 742                default:
 743                        printk(KERN_WARNING "PDC reported unknown LCD/LED model %d\n",
 744                               lcd_info.model);
 745                        goto not_found;
 746                } /* switch() */
 747
 748found:
 749                /* register the LCD/LED driver */
 750                register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
 751                return 0;
 752
 753        } else { /* if() */
 754                DPRINTK((KERN_INFO "pdc_chassis_info call failed with retval = %d\n", ret));
 755        }
 756
 757not_found:
 758        lcd_info.model = DISPLAY_MODEL_NONE;
 759        return 1;
 760}
 761
 762static void __exit led_exit(void)
 763{
 764        unregister_reboot_notifier(&led_notifier);
 765        return;
 766}
 767
 768#ifdef CONFIG_PROC_FS
 769module_init(led_create_procfs)
 770#endif
 771