drivers/parisc/led.c

   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 2001-2005 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/config.h>
  27 #include <linux/module.h>
  28 #include <linux/stddef.h>       /* for offsetof() */
  29 #include <linux/init.h>
  30 #include <linux/types.h>
  31 #include <linux/ioport.h>
  32 #include <linux/utsname.h>
  33 #include <linux/capability.h>
  34 #include <linux/delay.h>
  35 #include <linux/netdevice.h>
  36 #include <linux/inetdevice.h>
  37 #include <linux/in.h>
  38 #include <linux/interrupt.h>
  39 #include <linux/kernel_stat.h>
  40 #include <linux/reboot.h>
  41 #include <linux/proc_fs.h>
  42 #include <linux/ctype.h>
  43 #include <linux/blkdev.h>
  44 #include <linux/workqueue.h>
  45 #include <linux/rcupdate.h>
  46 #include <asm/io.h>
  47 #include <asm/processor.h>
  48 #include <asm/hardware.h>
  49 #include <asm/param.h>          /* HZ */
  50 #include <asm/led.h>
  51 #include <asm/pdc.h>
  52 #include <asm/uaccess.h>
  53
  54 /* The control of the LEDs and LCDs on PARISC-machines have to be done
  55    completely in software. The necessary calculations are done in a work queue
  56    task which is scheduled regularly, and since the calculations may consume a
  57    relatively large amount of CPU time, some of the calculations can be
  58    turned off with the following variables (controlled via procfs) */
  59
  60 static int led_type __read_mostly = -1;
  61 static unsigned char lastleds;  /* LED state from most recent update */
  62 static unsigned int led_heartbeat __read_mostly = 1;
  63 static unsigned int led_diskio    __read_mostly = 1;
  64 static unsigned int led_lanrxtx   __read_mostly = 1;
  65 static char lcd_text[32]          __read_mostly;
  66 static char lcd_text_default[32]  __read_mostly;
  67
  68
  69 static struct workqueue_struct *led_wq;
  70 static void led_work_func(void *);
  71 static DECLARE_WORK(led_task, led_work_func, NULL);
  72
  73 #if 0
  74 #define DPRINTK(x)      printk x
  75 #else
  76 #define DPRINTK(x)
  77 #endif
  78
  79 struct 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 */
  88 struct 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. */
 111 static struct pdc_chassis_lcd_info_ret_block
 112 lcd_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 */
 133 static 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_work(led_wq, &led_task);
 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_read(char *page, char **start, off_t off, int count,
 152         int *eof, void *data)
 153 {
 154         char *out = page;
 155         int len;
 156
 157         switch ((long)data)
 158         {
 159         case LED_NOLCD:
 160                 out += sprintf(out, "Heartbeat: %d\n", led_heartbeat);
 161                 out += sprintf(out, "Disk IO: %d\n", led_diskio);
 162                 out += sprintf(out, "LAN Rx/Tx: %d\n", led_lanrxtx);
 163                 break;
 164         case LED_HASLCD:
 165                 out += sprintf(out, "%s\n", lcd_text);
 166                 break;
 167         default:
 168                 *eof = 1;
 169                 return 0;
 170         }
 171
 172         len = out - page - off;
 173         if (len < count) {
 174                 *eof = 1;
 175                 if (len <= 0) return 0;
 176         } else {
 177                 len = count;
 178         }
 179         *start = page + off;
 180         return len;
 181 }
 182
 183 static int led_proc_write(struct file *file, const char *buf,
 184         unsigned long count, void *data)
 185 {
 186         char *cur, lbuf[count + 1];
 187         int d;
 188
 189         if (!capable(CAP_SYS_ADMIN))
 190                 return -EACCES;
 191
 192         memset(lbuf, 0, count + 1);
 193
 194         if (copy_from_user(lbuf, buf, count))
 195                 return -EFAULT;
 196
 197         cur = lbuf;
 198
 199         /* skip initial spaces */
 200         while (*cur && isspace(*cur))
 201         {
 202                 cur++;
 203         }
 204
 205         switch ((long)data)
 206         {
 207         case LED_NOLCD:
 208                 d = *cur++ - '0';
 209                 if (d != 0 && d != 1) goto parse_error;
 210                 led_heartbeat = d;
 211
 212                 if (*cur++ != ' ') goto parse_error;
 213
 214                 d = *cur++ - '0';
 215                 if (d != 0 && d != 1) goto parse_error;
 216                 led_diskio = d;
 217
 218                 if (*cur++ != ' ') goto parse_error;
 219
 220                 d = *cur++ - '0';
 221                 if (d != 0 && d != 1) goto parse_error;
 222                 led_lanrxtx = d;
 223
 224                 break;
 225         case LED_HASLCD:
 226                 if (*cur && cur[strlen(cur)-1] == '\n')
 227                         cur[strlen(cur)-1] = 0;
 228                 if (*cur == 0)
 229                         cur = lcd_text_default;
 230                 lcd_print(cur);
 231                 break;
 232         default:
 233                 return 0;
 234         }
 235
 236         return count;
 237
 238 parse_error:
 239         if ((long)data == LED_NOLCD)
 240                 printk(KERN_CRIT "Parse error: expect \"n n n\" (n == 0 or 1) for heartbeat,\ndisk io and lan tx/rx indicators\n");
 241         return -EINVAL;
 242 }
 243
 244 static int __init led_create_procfs(void)
 245 {
 246         struct proc_dir_entry *proc_pdc_root = NULL;
 247         struct proc_dir_entry *ent;
 248
 249         if (led_type == -1) return -1;
 250
 251         proc_pdc_root = proc_mkdir("pdc", 0);
 252         if (!proc_pdc_root) return -1;
 253         proc_pdc_root->owner = THIS_MODULE;
 254         ent = create_proc_entry("led", S_IFREG|S_IRUGO|S_IWUSR, proc_pdc_root);
 255         if (!ent) return -1;
 256         ent->nlink = 1;
 257         ent->data = (void *)LED_NOLCD; /* LED */
 258         ent->read_proc = led_proc_read;
 259         ent->write_proc = led_proc_write;
 260         ent->owner = THIS_MODULE;
 261
 262         if (led_type == LED_HASLCD)
 263         {
 264                 ent = create_proc_entry("lcd", S_IFREG|S_IRUGO|S_IWUSR, proc_pdc_root);
 265                 if (!ent) return -1;
 266                 ent->nlink = 1;
 267                 ent->data = (void *)LED_HASLCD; /* LCD */
 268                 ent->read_proc = led_proc_read;
 269                 ent->write_proc = led_proc_write;
 270                 ent->owner = THIS_MODULE;
 271         }
 272
 273         return 0;
 274 }
 275 #endif
 276
 277 /*
 278    **
 279    ** led_ASP_driver()
 280    **
 281  */
 282 #define LED_DATA        0x01    /* data to shift (0:on 1:off) */
 283 #define LED_STROBE      0x02    /* strobe to clock data */
 284 static void led_ASP_driver(unsigned char leds)
 285 {
 286         int i;
 287
 288         leds = ~leds;
 289         for (i = 0; i < 8; i++) {
 290                 unsigned char value;
 291                 value = (leds & 0x80) >> 7;
 292                 gsc_writeb( value,               LED_DATA_REG );
 293                 gsc_writeb( value | LED_STROBE,  LED_DATA_REG );
 294                 leds <<= 1;
 295         }
 296 }
 297
 298
 299 /*
 300    **
 301    ** led_LASI_driver()
 302    **
 303  */
 304 static void led_LASI_driver(unsigned char leds)
 305 {
 306         leds = ~leds;
 307         gsc_writeb( leds, LED_DATA_REG );
 308 }
 309
 310
 311 /*
 312    **
 313    ** led_LCD_driver()
 314    **
 315  */
 316 static void led_LCD_driver(unsigned char leds)
 317 {
 318         static int i;
 319         static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
 320                 LED_LAN_RCV, LED_LAN_TX };
 321
 322         static struct lcd_block * blockp[4] = {
 323                 &lcd_info.heartbeat,
 324                 &lcd_info.disk_io,
 325                 &lcd_info.lan_rcv,
 326                 &lcd_info.lan_tx
 327         };
 328
 329         /* Convert min_cmd_delay to milliseconds */
 330         unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
 331
 332         for (i=0; i<4; ++i)
 333         {
 334                 if ((leds & mask[i]) != (lastleds & mask[i]))
 335                 {
 336                         gsc_writeb( blockp[i]->command, LCD_CMD_REG );
 337                         msleep(msec_cmd_delay);
 338
 339                         gsc_writeb( leds & mask[i] ? blockp[i]->on :
 340                                         blockp[i]->off, LCD_DATA_REG );
 341                         msleep(msec_cmd_delay);
 342                 }
 343         }
 344 }
 345
 346
 347 /*
 348    **
 349    ** led_get_net_activity()
 350    **
 351    ** calculate if there was TX- or RX-throughput on the network interfaces
 352    ** (analog to dev_get_info() from net/core/dev.c)
 353    **
 354  */
 355 static __inline__ int led_get_net_activity(void)
 356 {
 357 #ifndef CONFIG_NET
 358         return 0;
 359 #else
 360         static unsigned long rx_total_last, tx_total_last;
 361         unsigned long rx_total, tx_total;
 362         struct net_device *dev;
 363         int retval;
 364
 365         rx_total = tx_total = 0;
 366
 367         /* we are running as a workqueue task, so locking dev_base
 368          * for reading should be OK */
 369         read_lock(&dev_base_lock);
 370         rcu_read_lock();
 371         for (dev = dev_base; dev; dev = dev->next) {
 372             struct net_device_stats *stats;
 373             struct in_device *in_dev = __in_dev_get_rcu(dev);
 374             if (!in_dev || !in_dev->ifa_list)
 375                 continue;
 376             if (LOOPBACK(in_dev->ifa_list->ifa_local))
 377                 continue;
 378             if (!dev->get_stats)
 379                 continue;
 380             stats = dev->get_stats(dev);
 381             rx_total += stats->rx_packets;
 382             tx_total += stats->tx_packets;
 383         }
 384         rcu_read_unlock();
 385         read_unlock(&dev_base_lock);
 386
 387         retval = 0;
 388
 389         if (rx_total != rx_total_last) {
 390                 rx_total_last = rx_total;
 391                 retval |= LED_LAN_RCV;
 392         }
 393
 394         if (tx_total != tx_total_last) {
 395                 tx_total_last = tx_total;
 396                 retval |= LED_LAN_TX;
 397         }
 398
 399         return retval;
 400 #endif
 401 }
 402
 403
 404 /*
 405    **
 406    ** led_get_diskio_activity()
 407    **
 408    ** calculate if there was disk-io in the system
 409    **
 410  */
 411 static __inline__ int led_get_diskio_activity(void)
 412 {
 413         static unsigned long last_pgpgin, last_pgpgout;
 414         struct page_state pgstat;
 415         int changed;
 416
 417         get_full_page_state(&pgstat); /* get no of sectors in & out */
 418
 419         /* Just use a very simple calculation here. Do not care about overflow,
 420            since we only want to know if there was activity or not. */
 421         changed = (pgstat.pgpgin != last_pgpgin) || (pgstat.pgpgout != last_pgpgout);
 422         last_pgpgin  = pgstat.pgpgin;
 423         last_pgpgout = pgstat.pgpgout;
 424
 425         return (changed ? LED_DISK_IO : 0);
 426 }
 427
 428
 429
 430 /*
 431    ** led_work_func()
 432    **
 433    ** manages when and which chassis LCD/LED gets updated
 434
 435     TODO:
 436     - display load average (older machines like 715/64 have 4 "free" LED's for that)
 437     - optimizations
 438  */
 439
 440 #define HEARTBEAT_LEN (HZ*10/100)
 441 #define HEARTBEAT_2ND_RANGE_START (HZ*28/100)
 442 #define HEARTBEAT_2ND_RANGE_END   (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)
 443
 444 #define LED_UPDATE_INTERVAL (1 + (HZ*19/1000))
 445
 446 static void led_work_func (void *unused)
 447 {
 448         static unsigned long last_jiffies;
 449         static unsigned long count_HZ; /* counter in range 0..HZ */
 450         unsigned char currentleds = 0; /* stores current value of the LEDs */
 451
 452         /* exit if not initialized */
 453         if (!led_func_ptr)
 454             return;
 455
 456         /* increment the heartbeat timekeeper */
 457         count_HZ += jiffies - last_jiffies;
 458         last_jiffies = jiffies;
 459         if (count_HZ >= HZ)
 460             count_HZ = 0;
 461
 462         if (likely(led_heartbeat))
 463         {
 464                 /* flash heartbeat-LED like a real heart
 465                  * (2 x short then a long delay)
 466                  */
 467                 if (count_HZ < HEARTBEAT_LEN ||
 468                                 (count_HZ >= HEARTBEAT_2ND_RANGE_START &&
 469                                 count_HZ < HEARTBEAT_2ND_RANGE_END))
 470                         currentleds |= LED_HEARTBEAT;
 471         }
 472
 473         if (likely(led_lanrxtx))  currentleds |= led_get_net_activity();
 474         if (likely(led_diskio))   currentleds |= led_get_diskio_activity();
 475
 476         /* blink all LEDs twice a second if we got an Oops (HPMC) */
 477         if (unlikely(oops_in_progress))
 478                 currentleds = (count_HZ<=(HZ/2)) ? 0 : 0xff;
 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_rearming_delayed_workqueue(led_wq, &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                 LED_DATA_REG = data_reg;
 567                 led_func_ptr = led_LASI_driver;
 568                 printk(KERN_INFO "LED display at %lx registered\n", LED_DATA_REG);
 569                 led_type = LED_NOLCD;
 570                 break;
 571
 572         case DISPLAY_MODEL_OLD_ASP:
 573                 LED_DATA_REG = data_reg;
 574                 led_func_ptr = led_ASP_driver;
 575                 printk(KERN_INFO "LED (ASP-style) display at %lx registered\n",
 576                     LED_DATA_REG);
 577                 led_type = LED_NOLCD;
 578                 break;
 579
 580         default:
 581                 printk(KERN_ERR "%s: Wrong LCD/LED model %d !\n",
 582                        __FUNCTION__, lcd_info.model);
 583                 return 1;
 584         }
 585
 586         /* mark the LCD/LED driver now as initialized and
 587          * register to the reboot notifier chain */
 588         initialized++;
 589         register_reboot_notifier(&led_notifier);
 590
 591         /* Ensure the work is queued */
 592         if (led_wq) {
 593                 queue_work(led_wq, &led_task);
 594         }
 595
 596         return 0;
 597 }
 598
 599 /*
 600    ** register_led_regions()
 601    **
 602    ** register_led_regions() registers the LCD/LED regions for /procfs.
 603    ** At bootup - where the initialisation of the LCD/LED normally happens -
 604    ** not all internal structures of request_region() are properly set up,
 605    ** so that we delay the led-registration until after busdevices_init()
 606    ** has been executed.
 607    **
 608  */
 609
 610 void __init register_led_regions(void)
 611 {
 612         switch (lcd_info.model) {
 613         case DISPLAY_MODEL_LCD:
 614                 request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
 615                 request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
 616                 break;
 617         case DISPLAY_MODEL_LASI:
 618         case DISPLAY_MODEL_OLD_ASP:
 619                 request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
 620                 break;
 621         }
 622 }
 623
 624
 625 /*
 626    **
 627    ** lcd_print()
 628    **
 629    ** Displays the given string on the LCD-Display of newer machines.
 630    ** lcd_print() disables/enables the timer-based led work queue to
 631    ** avoid a race condition while writing the CMD/DATA register pair.
 632    **
 633  */
 634 int lcd_print( char *str )
 635 {
 636         int i;
 637
 638         if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
 639             return 0;
 640
 641         /* temporarily disable the led work task */
 642         if (led_wq)
 643                 cancel_rearming_delayed_workqueue(led_wq, &led_task);
 644
 645         /* copy display string to buffer for procfs */
 646         strlcpy(lcd_text, str, sizeof(lcd_text));
 647
 648         /* Set LCD Cursor to 1st character */
 649         gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
 650         udelay(lcd_info.min_cmd_delay);
 651
 652         /* Print the string */
 653         for (i=0; i < lcd_info.lcd_width; i++) {
 654             if (str && *str)
 655                 gsc_writeb(*str++, LCD_DATA_REG);
 656             else
 657                 gsc_writeb(' ', LCD_DATA_REG);
 658             udelay(lcd_info.min_cmd_delay);
 659         }
 660
 661         /* re-queue the work */
 662         if (led_wq) {
 663                 queue_work(led_wq, &led_task);
 664         }
 665
 666         return lcd_info.lcd_width;
 667 }
 668
 669 /*
 670    ** led_init()
 671    **
 672    ** led_init() is called very early in the bootup-process from setup.c
 673    ** and asks the PDC for an usable chassis LCD or LED.
 674    ** If the PDC doesn't return any info, then the LED
 675    ** is detected by lasi.c or asp.c and registered with the
 676    ** above functions lasi_led_init() or asp_led_init().
 677    ** KittyHawk machines have often a buggy PDC, so that
 678    ** we explicitly check for those machines here.
 679  */
 680
 681 int __init led_init(void)
 682 {
 683         struct pdc_chassis_info chassis_info;
 684         int ret;
 685
 686         snprintf(lcd_text_default, sizeof(lcd_text_default),
 687                 "Linux %s", system_utsname.release);
 688
 689         /* Work around the buggy PDC of KittyHawk-machines */
 690         switch (CPU_HVERSION) {
 691         case 0x580:             /* KittyHawk DC2-100 (K100) */
 692         case 0x581:             /* KittyHawk DC3-120 (K210) */
 693         case 0x582:             /* KittyHawk DC3 100 (K400) */
 694         case 0x583:             /* KittyHawk DC3 120 (K410) */
 695         case 0x58B:             /* KittyHawk DC2 100 (K200) */
 696                 printk(KERN_INFO "%s: KittyHawk-Machine (hversion 0x%x) found, "
 697                                 "LED detection skipped.\n", __FILE__, CPU_HVERSION);
 698                 goto found;     /* use the preinitialized values of lcd_info */
 699         }
 700
 701         /* initialize the struct, so that we can check for valid return values */
 702         lcd_info.model = DISPLAY_MODEL_NONE;
 703         chassis_info.actcnt = chassis_info.maxcnt = 0;
 704
 705         ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
 706         if (ret == PDC_OK) {
 707                 DPRINTK((KERN_INFO "%s: chassis info: model=%d (%s), "
 708                          "lcd_width=%d, cmd_delay=%u,\n"
 709                          "%s: sizecnt=%d, actcnt=%ld, maxcnt=%ld\n",
 710                          __FILE__, lcd_info.model,
 711                          (lcd_info.model==DISPLAY_MODEL_LCD) ? "LCD" :
 712                           (lcd_info.model==DISPLAY_MODEL_LASI) ? "LED" : "unknown",
 713                          lcd_info.lcd_width, lcd_info.min_cmd_delay,
 714                          __FILE__, sizeof(lcd_info),
 715                          chassis_info.actcnt, chassis_info.maxcnt));
 716                 DPRINTK((KERN_INFO "%s: cmd=%p, data=%p, reset1=%x, reset2=%x, act_enable=%d\n",
 717                         __FILE__, lcd_info.lcd_cmd_reg_addr,
 718                         lcd_info.lcd_data_reg_addr, lcd_info.reset_cmd1,
 719                         lcd_info.reset_cmd2, lcd_info.act_enable ));
 720
 721                 /* check the results. Some machines have a buggy PDC */
 722                 if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
 723                         goto not_found;
 724
 725                 switch (lcd_info.model) {
 726                 case DISPLAY_MODEL_LCD:         /* LCD display */
 727                         if (chassis_info.actcnt <
 728                                 offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
 729                                 goto not_found;
 730                         if (!lcd_info.act_enable) {
 731                                 DPRINTK((KERN_INFO "PDC prohibited usage of the LCD.\n"));
 732                                 goto not_found;
 733                         }
 734                         break;
 735
 736                 case DISPLAY_MODEL_NONE:        /* no LED or LCD available */
 737                         printk(KERN_INFO "PDC reported no LCD or LED.\n");
 738                         goto not_found;
 739
 740                 case DISPLAY_MODEL_LASI:        /* Lasi style 8 bit LED display */
 741                         if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
 742                                 goto not_found;
 743                         break;
 744
 745                 default:
 746                         printk(KERN_WARNING "PDC reported unknown LCD/LED model %d\n",
 747                                lcd_info.model);
 748                         goto not_found;
 749                 } /* switch() */
 750
 751 found:
 752                 /* register the LCD/LED driver */
 753                 register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
 754                 return 0;
 755
 756         } else { /* if() */
 757                 DPRINTK((KERN_INFO "pdc_chassis_info call failed with retval = %d\n", ret));
 758         }
 759
 760 not_found:
 761         lcd_info.model = DISPLAY_MODEL_NONE;
 762         return 1;
 763 }
 764
 765 static void __exit led_exit(void)
 766 {
 767         unregister_reboot_notifier(&led_notifier);
 768         return;
 769 }
 770
 771 #ifdef CONFIG_PROC_FS
 772 module_init(led_create_procfs)
 773 #endif