Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
led.c
Go to the documentation of this file.
1 /*
2  * Chassis LCD/LED driver for HP-PARISC workstations
3  *
4  * (c) Copyright 2000 Red Hat Software
5  * (c) Copyright 2000 Helge Deller <[email protected]>
6  * (c) Copyright 2001-2009 Helge Deller <[email protected]>
7  * (c) Copyright 2001 Randolph Chung <[email protected]>
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 <[email protected]>
21  * - Switch from using a tasklet to a work queue, so the led_LCD_driver
22  * can sleep.
23  * David Pye <[email protected]>
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 
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 static int lcd_no_led_support __read_mostly = 0; /* KittyHawk doesn't support LED on its LCD */
68 
69 
70 static struct workqueue_struct *led_wq;
71 static void led_work_func(struct work_struct *);
72 static DECLARE_DELAYED_WORK(led_task, led_work_func);
73 
74 #if 0
75 #define DPRINTK(x) printk x
76 #else
77 #define DPRINTK(x)
78 #endif
79 
80 struct lcd_block {
81  unsigned char command; /* stores the command byte */
82  unsigned char on; /* value for turning LED on */
83  unsigned char off; /* value for turning LED off */
84 };
85 
86 /* Structure returned by PDC_RETURN_CHASSIS_INFO */
87 /* NOTE: we use unsigned long:16 two times, since the following member
88  lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
90  unsigned long model:16; /* DISPLAY_MODEL_XXXX */
91  unsigned long lcd_width:16; /* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
92  unsigned long lcd_cmd_reg_addr; /* ptr to LCD cmd-register & data ptr for LED */
93  unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
94  unsigned int min_cmd_delay; /* delay in uS after cmd-write (LCD only) */
95  unsigned char reset_cmd1; /* command #1 for writing LCD string (LCD only) */
96  unsigned char reset_cmd2; /* command #2 for writing LCD string (LCD only) */
97  unsigned char act_enable; /* 0 = no activity (LCD only) */
102  char _pad;
103 };
104 
105 
106 /* LCD_CMD and LCD_DATA for KittyHawk machines */
107 #define KITTYHAWK_LCD_CMD F_EXTEND(0xf0190000UL) /* 64bit-ready */
108 #define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD+1)
109 
110 /* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's
111  * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
112 static struct pdc_chassis_lcd_info_ret_block
113 lcd_info __attribute__((aligned(8))) __read_mostly =
114 {
115  .model = DISPLAY_MODEL_LCD,
116  .lcd_width = 16,
117  .lcd_cmd_reg_addr = KITTYHAWK_LCD_CMD,
118  .lcd_data_reg_addr = KITTYHAWK_LCD_DATA,
119  .min_cmd_delay = 80,
120  .reset_cmd1 = 0x80,
121  .reset_cmd2 = 0xc0,
122 };
123 
124 
125 /* direct access to some of the lcd_info variables */
126 #define LCD_CMD_REG lcd_info.lcd_cmd_reg_addr
127 #define LCD_DATA_REG lcd_info.lcd_data_reg_addr
128 #define LED_DATA_REG lcd_info.lcd_cmd_reg_addr /* LASI & ASP only */
129 
130 #define LED_HASLCD 1
131 #define LED_NOLCD 0
132 
133 /* The workqueue must be created at init-time */
134 static int start_task(void)
135 {
136  /* Display the default text now */
137  if (led_type == LED_HASLCD) lcd_print( lcd_text_default );
138 
139  /* KittyHawk has no LED support on its LCD */
140  if (lcd_no_led_support) return 0;
141 
142  /* Create the work queue and queue the LED task */
143  led_wq = create_singlethread_workqueue("led_wq");
144  queue_delayed_work(led_wq, &led_task, 0);
145 
146  return 0;
147 }
148 
149 device_initcall(start_task);
150 
151 /* ptr to LCD/LED-specific function */
152 static void (*led_func_ptr) (unsigned char) __read_mostly;
153 
154 #ifdef CONFIG_PROC_FS
155 static int led_proc_show(struct seq_file *m, void *v)
156 {
157  switch ((long)m->private)
158  {
159  case LED_NOLCD:
160  seq_printf(m, "Heartbeat: %d\n", led_heartbeat);
161  seq_printf(m, "Disk IO: %d\n", led_diskio);
162  seq_printf(m, "LAN Rx/Tx: %d\n", led_lanrxtx);
163  break;
164  case LED_HASLCD:
165  seq_printf(m, "%s\n", lcd_text);
166  break;
167  default:
168  return 0;
169  }
170  return 0;
171 }
172 
173 static int led_proc_open(struct inode *inode, struct file *file)
174 {
175  return single_open(file, led_proc_show, PDE(inode)->data);
176 }
177 
178 
179 static ssize_t led_proc_write(struct file *file, const char *buf,
180  size_t count, loff_t *pos)
181 {
182  void *data = PDE(file->f_path.dentry->d_inode)->data;
183  char *cur, lbuf[32];
184  int d;
185 
186  if (!capable(CAP_SYS_ADMIN))
187  return -EACCES;
188 
189  if (count >= sizeof(lbuf))
190  count = sizeof(lbuf)-1;
191 
192  if (copy_from_user(lbuf, buf, count))
193  return -EFAULT;
194  lbuf[count] = 0;
195 
196  cur = lbuf;
197 
198  switch ((long)data)
199  {
200  case LED_NOLCD:
201  d = *cur++ - '0';
202  if (d != 0 && d != 1) goto parse_error;
203  led_heartbeat = d;
204 
205  if (*cur++ != ' ') goto parse_error;
206 
207  d = *cur++ - '0';
208  if (d != 0 && d != 1) goto parse_error;
209  led_diskio = d;
210 
211  if (*cur++ != ' ') goto parse_error;
212 
213  d = *cur++ - '0';
214  if (d != 0 && d != 1) goto parse_error;
215  led_lanrxtx = d;
216 
217  break;
218  case LED_HASLCD:
219  if (*cur && cur[strlen(cur)-1] == '\n')
220  cur[strlen(cur)-1] = 0;
221  if (*cur == 0)
222  cur = lcd_text_default;
223  lcd_print(cur);
224  break;
225  default:
226  return 0;
227  }
228 
229  return count;
230 
231 parse_error:
232  if ((long)data == LED_NOLCD)
233  printk(KERN_CRIT "Parse error: expect \"n n n\" (n == 0 or 1) for heartbeat,\ndisk io and lan tx/rx indicators\n");
234  return -EINVAL;
235 }
236 
237 static const struct file_operations led_proc_fops = {
238  .owner = THIS_MODULE,
239  .open = led_proc_open,
240  .read = seq_read,
241  .llseek = seq_lseek,
242  .release = single_release,
243  .write = led_proc_write,
244 };
245 
246 static int __init led_create_procfs(void)
247 {
248  struct proc_dir_entry *proc_pdc_root = NULL;
249  struct proc_dir_entry *ent;
250 
251  if (led_type == -1) return -1;
252 
253  proc_pdc_root = proc_mkdir("pdc", 0);
254  if (!proc_pdc_root) return -1;
255 
256  if (!lcd_no_led_support)
257  {
258  ent = proc_create_data("led", S_IRUGO|S_IWUSR, proc_pdc_root,
259  &led_proc_fops, (void *)LED_NOLCD); /* LED */
260  if (!ent) return -1;
261  }
262 
263  if (led_type == LED_HASLCD)
264  {
265  ent = proc_create_data("lcd", S_IRUGO|S_IWUSR, proc_pdc_root,
266  &led_proc_fops, (void *)LED_HASLCD); /* LCD */
267  if (!ent) return -1;
268  }
269 
270  return 0;
271 }
272 #endif
273 
274 /*
275  **
276  ** led_ASP_driver()
277  **
278  */
279 #define LED_DATA 0x01 /* data to shift (0:on 1:off) */
280 #define LED_STROBE 0x02 /* strobe to clock data */
281 static void led_ASP_driver(unsigned char leds)
282 {
283  int i;
284 
285  leds = ~leds;
286  for (i = 0; i < 8; i++) {
287  unsigned char value;
288  value = (leds & 0x80) >> 7;
289  gsc_writeb( value, LED_DATA_REG );
290  gsc_writeb( value | LED_STROBE, LED_DATA_REG );
291  leds <<= 1;
292  }
293 }
294 
295 
296 /*
297  **
298  ** led_LASI_driver()
299  **
300  */
301 static void led_LASI_driver(unsigned char leds)
302 {
303  leds = ~leds;
304  gsc_writeb( leds, LED_DATA_REG );
305 }
306 
307 
308 /*
309  **
310  ** led_LCD_driver()
311  **
312  */
313 static void led_LCD_driver(unsigned char leds)
314 {
315  static int i;
316  static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
318 
319  static struct lcd_block * blockp[4] = {
320  &lcd_info.heartbeat,
321  &lcd_info.disk_io,
322  &lcd_info.lan_rcv,
323  &lcd_info.lan_tx
324  };
325 
326  /* Convert min_cmd_delay to milliseconds */
327  unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
328 
329  for (i=0; i<4; ++i)
330  {
331  if ((leds & mask[i]) != (lastleds & mask[i]))
332  {
333  gsc_writeb( blockp[i]->command, LCD_CMD_REG );
334  msleep(msec_cmd_delay);
335 
336  gsc_writeb( leds & mask[i] ? blockp[i]->on :
337  blockp[i]->off, LCD_DATA_REG );
338  msleep(msec_cmd_delay);
339  }
340  }
341 }
342 
343 
344 /*
345  **
346  ** led_get_net_activity()
347  **
348  ** calculate if there was TX- or RX-throughput on the network interfaces
349  ** (analog to dev_get_info() from net/core/dev.c)
350  **
351  */
352 static __inline__ int led_get_net_activity(void)
353 {
354 #ifndef CONFIG_NET
355  return 0;
356 #else
357  static u64 rx_total_last, tx_total_last;
358  u64 rx_total, tx_total;
359  struct net_device *dev;
360  int retval;
361 
362  rx_total = tx_total = 0;
363 
364  /* we are running as a workqueue task, so we can use an RCU lookup */
365  rcu_read_lock();
367  const struct rtnl_link_stats64 *stats;
368  struct rtnl_link_stats64 temp;
369  struct in_device *in_dev = __in_dev_get_rcu(dev);
370  if (!in_dev || !in_dev->ifa_list)
371  continue;
372  if (ipv4_is_loopback(in_dev->ifa_list->ifa_local))
373  continue;
374  stats = dev_get_stats(dev, &temp);
375  rx_total += stats->rx_packets;
376  tx_total += stats->tx_packets;
377  }
378  rcu_read_unlock();
379 
380  retval = 0;
381 
382  if (rx_total != rx_total_last) {
383  rx_total_last = rx_total;
384  retval |= LED_LAN_RCV;
385  }
386 
387  if (tx_total != tx_total_last) {
388  tx_total_last = tx_total;
389  retval |= LED_LAN_TX;
390  }
391 
392  return retval;
393 #endif
394 }
395 
396 
397 /*
398  **
399  ** led_get_diskio_activity()
400  **
401  ** calculate if there was disk-io in the system
402  **
403  */
404 static __inline__ int led_get_diskio_activity(void)
405 {
406  static unsigned long last_pgpgin, last_pgpgout;
407  unsigned long events[NR_VM_EVENT_ITEMS];
408  int changed;
409 
410  all_vm_events(events);
411 
412  /* Just use a very simple calculation here. Do not care about overflow,
413  since we only want to know if there was activity or not. */
414  changed = (events[PGPGIN] != last_pgpgin) ||
415  (events[PGPGOUT] != last_pgpgout);
416  last_pgpgin = events[PGPGIN];
417  last_pgpgout = events[PGPGOUT];
418 
419  return (changed ? LED_DISK_IO : 0);
420 }
421 
422 
423 
424 /*
425  ** led_work_func()
426  **
427  ** manages when and which chassis LCD/LED gets updated
428 
429  TODO:
430  - display load average (older machines like 715/64 have 4 "free" LED's for that)
431  - optimizations
432  */
433 
434 #define HEARTBEAT_LEN (HZ*10/100)
435 #define HEARTBEAT_2ND_RANGE_START (HZ*28/100)
436 #define HEARTBEAT_2ND_RANGE_END (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)
437 
438 #define LED_UPDATE_INTERVAL (1 + (HZ*19/1000))
439 
440 static void led_work_func (struct work_struct *unused)
441 {
442  static unsigned long last_jiffies;
443  static unsigned long count_HZ; /* counter in range 0..HZ */
444  unsigned char currentleds = 0; /* stores current value of the LEDs */
445 
446  /* exit if not initialized */
447  if (!led_func_ptr)
448  return;
449 
450  /* increment the heartbeat timekeeper */
451  count_HZ += jiffies - last_jiffies;
452  last_jiffies = jiffies;
453  if (count_HZ >= HZ)
454  count_HZ = 0;
455 
456  if (likely(led_heartbeat))
457  {
458  /* flash heartbeat-LED like a real heart
459  * (2 x short then a long delay)
460  */
461  if (count_HZ < HEARTBEAT_LEN ||
462  (count_HZ >= HEARTBEAT_2ND_RANGE_START &&
463  count_HZ < HEARTBEAT_2ND_RANGE_END))
464  currentleds |= LED_HEARTBEAT;
465  }
466 
467  if (likely(led_lanrxtx)) currentleds |= led_get_net_activity();
468  if (likely(led_diskio)) currentleds |= led_get_diskio_activity();
469 
470  /* blink LEDs if we got an Oops (HPMC) */
471  if (unlikely(oops_in_progress)) {
472  if (boot_cpu_data.cpu_type >= pcxl2) {
473  /* newer machines don't have loadavg. LEDs, so we
474  * let all LEDs blink twice per second instead */
475  currentleds = (count_HZ <= (HZ/2)) ? 0 : 0xff;
476  } else {
477  /* old machines: blink loadavg. LEDs twice per second */
478  if (count_HZ <= (HZ/2))
479  currentleds &= ~(LED4|LED5|LED6|LED7);
480  else
481  currentleds |= (LED4|LED5|LED6|LED7);
482  }
483  }
484 
485  if (currentleds != lastleds)
486  {
487  led_func_ptr(currentleds); /* Update the LCD/LEDs */
488  lastleds = currentleds;
489  }
490 
491  queue_delayed_work(led_wq, &led_task, LED_UPDATE_INTERVAL);
492 }
493 
494 /*
495  ** led_halt()
496  **
497  ** called by the reboot notifier chain at shutdown and stops all
498  ** LED/LCD activities.
499  **
500  */
501 
502 static int led_halt(struct notifier_block *, unsigned long, void *);
503 
504 static struct notifier_block led_notifier = {
505  .notifier_call = led_halt,
506 };
507 static int notifier_disabled = 0;
508 
509 static int led_halt(struct notifier_block *nb, unsigned long event, void *buf)
510 {
511  char *txt;
512 
513  if (notifier_disabled)
514  return NOTIFY_OK;
515 
516  notifier_disabled = 1;
517  switch (event) {
518  case SYS_RESTART: txt = "SYSTEM RESTART";
519  break;
520  case SYS_HALT: txt = "SYSTEM HALT";
521  break;
522  case SYS_POWER_OFF: txt = "SYSTEM POWER OFF";
523  break;
524  default: return NOTIFY_DONE;
525  }
526 
527  /* Cancel the work item and delete the queue */
528  if (led_wq) {
529  cancel_delayed_work_sync(&led_task);
530  destroy_workqueue(led_wq);
531  led_wq = NULL;
532  }
533 
534  if (lcd_info.model == DISPLAY_MODEL_LCD)
535  lcd_print(txt);
536  else
537  if (led_func_ptr)
538  led_func_ptr(0xff); /* turn all LEDs ON */
539 
540  return NOTIFY_OK;
541 }
542 
543 /*
544  ** register_led_driver()
545  **
546  ** registers an external LED or LCD for usage by this driver.
547  ** currently only LCD-, LASI- and ASP-style LCD/LED's are supported.
548  **
549  */
550 
551 int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
552 {
553  static int initialized;
554 
555  if (initialized || !data_reg)
556  return 1;
557 
558  lcd_info.model = model; /* store the values */
559  LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;
560 
561  switch (lcd_info.model) {
562  case DISPLAY_MODEL_LCD:
563  LCD_DATA_REG = data_reg;
564  printk(KERN_INFO "LCD display at %lx,%lx registered\n",
566  led_func_ptr = led_LCD_driver;
568  break;
569 
570  case DISPLAY_MODEL_LASI:
571  LED_DATA_REG = data_reg;
572  led_func_ptr = led_LASI_driver;
573  printk(KERN_INFO "LED display at %lx registered\n", LED_DATA_REG);
575  break;
576 
578  LED_DATA_REG = data_reg;
579  led_func_ptr = led_ASP_driver;
580  printk(KERN_INFO "LED (ASP-style) display at %lx registered\n",
581  LED_DATA_REG);
583  break;
584 
585  default:
586  printk(KERN_ERR "%s: Wrong LCD/LED model %d !\n",
587  __func__, lcd_info.model);
588  return 1;
589  }
590 
591  /* mark the LCD/LED driver now as initialized and
592  * register to the reboot notifier chain */
593  initialized++;
594  register_reboot_notifier(&led_notifier);
595 
596  /* Ensure the work is queued */
597  if (led_wq) {
598  queue_delayed_work(led_wq, &led_task, 0);
599  }
600 
601  return 0;
602 }
603 
604 /*
605  ** register_led_regions()
606  **
607  ** register_led_regions() registers the LCD/LED regions for /procfs.
608  ** At bootup - where the initialisation of the LCD/LED normally happens -
609  ** not all internal structures of request_region() are properly set up,
610  ** so that we delay the led-registration until after busdevices_init()
611  ** has been executed.
612  **
613  */
614 
616 {
617  switch (lcd_info.model) {
618  case DISPLAY_MODEL_LCD:
619  request_mem_region((unsigned long)LCD_CMD_REG, 1, "lcd_cmd");
620  request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
621  break;
622  case DISPLAY_MODEL_LASI:
624  request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
625  break;
626  }
627 }
628 
629 
630 /*
631  **
632  ** lcd_print()
633  **
634  ** Displays the given string on the LCD-Display of newer machines.
635  ** lcd_print() disables/enables the timer-based led work queue to
636  ** avoid a race condition while writing the CMD/DATA register pair.
637  **
638  */
639 int lcd_print( const char *str )
640 {
641  int i;
642 
643  if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
644  return 0;
645 
646  /* temporarily disable the led work task */
647  if (led_wq)
648  cancel_delayed_work_sync(&led_task);
649 
650  /* copy display string to buffer for procfs */
651  strlcpy(lcd_text, str, sizeof(lcd_text));
652 
653  /* Set LCD Cursor to 1st character */
654  gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
655  udelay(lcd_info.min_cmd_delay);
656 
657  /* Print the string */
658  for (i=0; i < lcd_info.lcd_width; i++) {
659  if (str && *str)
660  gsc_writeb(*str++, LCD_DATA_REG);
661  else
662  gsc_writeb(' ', LCD_DATA_REG);
663  udelay(lcd_info.min_cmd_delay);
664  }
665 
666  /* re-queue the work */
667  if (led_wq) {
668  queue_delayed_work(led_wq, &led_task, 0);
669  }
670 
671  return lcd_info.lcd_width;
672 }
673 
674 /*
675  ** led_init()
676  **
677  ** led_init() is called very early in the bootup-process from setup.c
678  ** and asks the PDC for an usable chassis LCD or LED.
679  ** If the PDC doesn't return any info, then the LED
680  ** is detected by lasi.c or asp.c and registered with the
681  ** above functions lasi_led_init() or asp_led_init().
682  ** KittyHawk machines have often a buggy PDC, so that
683  ** we explicitly check for those machines here.
684  */
685 
686 int __init led_init(void)
687 {
688  struct pdc_chassis_info chassis_info;
689  int ret;
690 
691  snprintf(lcd_text_default, sizeof(lcd_text_default),
692  "Linux %s", init_utsname()->release);
693 
694  /* Work around the buggy PDC of KittyHawk-machines */
695  switch (CPU_HVERSION) {
696  case 0x580: /* KittyHawk DC2-100 (K100) */
697  case 0x581: /* KittyHawk DC3-120 (K210) */
698  case 0x582: /* KittyHawk DC3 100 (K400) */
699  case 0x583: /* KittyHawk DC3 120 (K410) */
700  case 0x58B: /* KittyHawk DC2 100 (K200) */
701  printk(KERN_INFO "%s: KittyHawk-Machine (hversion 0x%x) found, "
702  "LED detection skipped.\n", __FILE__, CPU_HVERSION);
703  lcd_no_led_support = 1;
704  goto found; /* use the preinitialized values of lcd_info */
705  }
706 
707  /* initialize the struct, so that we can check for valid return values */
708  lcd_info.model = DISPLAY_MODEL_NONE;
709  chassis_info.actcnt = chassis_info.maxcnt = 0;
710 
711  ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
712  if (ret == PDC_OK) {
713  DPRINTK((KERN_INFO "%s: chassis info: model=%d (%s), "
714  "lcd_width=%d, cmd_delay=%u,\n"
715  "%s: sizecnt=%d, actcnt=%ld, maxcnt=%ld\n",
716  __FILE__, lcd_info.model,
717  (lcd_info.model==DISPLAY_MODEL_LCD) ? "LCD" :
718  (lcd_info.model==DISPLAY_MODEL_LASI) ? "LED" : "unknown",
719  lcd_info.lcd_width, lcd_info.min_cmd_delay,
720  __FILE__, sizeof(lcd_info),
721  chassis_info.actcnt, chassis_info.maxcnt));
722  DPRINTK((KERN_INFO "%s: cmd=%p, data=%p, reset1=%x, reset2=%x, act_enable=%d\n",
723  __FILE__, lcd_info.lcd_cmd_reg_addr,
724  lcd_info.lcd_data_reg_addr, lcd_info.reset_cmd1,
725  lcd_info.reset_cmd2, lcd_info.act_enable ));
726 
727  /* check the results. Some machines have a buggy PDC */
728  if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
729  goto not_found;
730 
731  switch (lcd_info.model) {
732  case DISPLAY_MODEL_LCD: /* LCD display */
733  if (chassis_info.actcnt <
735  goto not_found;
736  if (!lcd_info.act_enable) {
737  DPRINTK((KERN_INFO "PDC prohibited usage of the LCD.\n"));
738  goto not_found;
739  }
740  break;
741 
742  case DISPLAY_MODEL_NONE: /* no LED or LCD available */
743  printk(KERN_INFO "PDC reported no LCD or LED.\n");
744  goto not_found;
745 
746  case DISPLAY_MODEL_LASI: /* Lasi style 8 bit LED display */
747  if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
748  goto not_found;
749  break;
750 
751  default:
752  printk(KERN_WARNING "PDC reported unknown LCD/LED model %d\n",
753  lcd_info.model);
754  goto not_found;
755  } /* switch() */
756 
757 found:
758  /* register the LCD/LED driver */
759  register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
760  return 0;
761 
762  } else { /* if() */
763  DPRINTK((KERN_INFO "pdc_chassis_info call failed with retval = %d\n", ret));
764  }
765 
766 not_found:
767  lcd_info.model = DISPLAY_MODEL_NONE;
768  return 1;
769 }
770 
771 static void __exit led_exit(void)
772 {
773  unregister_reboot_notifier(&led_notifier);
774  return;
775 }
776 
777 #ifdef CONFIG_PROC_FS
778 module_init(led_create_procfs)
779 #endif