cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
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led.c (20221B)


      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *    Chassis LCD/LED driver for HP-PARISC workstations
      4 *
      5 *      (c) Copyright 2000 Red Hat Software
      6 *      (c) Copyright 2000 Helge Deller <hdeller@redhat.com>
      7 *      (c) Copyright 2001-2009 Helge Deller <deller@gmx.de>
      8 *      (c) Copyright 2001 Randolph Chung <tausq@debian.org>
      9 *
     10 * TODO:
     11 *	- speed-up calculations with inlined assembler
     12 *	- interface to write to second row of LCD from /proc (if technically possible)
     13 *
     14 * Changes:
     15 *      - Audit copy_from_user in led_proc_write.
     16 *                                Daniele Bellucci <bellucda@tiscali.it>
     17 *	- Switch from using a tasklet to a work queue, so the led_LCD_driver
     18 *	  	can sleep.
     19 *	  			  David Pye <dmp@davidmpye.dyndns.org>
     20 */
     21
     22#include <linux/module.h>
     23#include <linux/stddef.h>	/* for offsetof() */
     24#include <linux/init.h>
     25#include <linux/types.h>
     26#include <linux/ioport.h>
     27#include <linux/utsname.h>
     28#include <linux/capability.h>
     29#include <linux/delay.h>
     30#include <linux/netdevice.h>
     31#include <linux/inetdevice.h>
     32#include <linux/in.h>
     33#include <linux/interrupt.h>
     34#include <linux/kernel_stat.h>
     35#include <linux/reboot.h>
     36#include <linux/proc_fs.h>
     37#include <linux/seq_file.h>
     38#include <linux/ctype.h>
     39#include <linux/blkdev.h>
     40#include <linux/workqueue.h>
     41#include <linux/rcupdate.h>
     42#include <asm/io.h>
     43#include <asm/processor.h>
     44#include <asm/hardware.h>
     45#include <asm/param.h>		/* HZ */
     46#include <asm/led.h>
     47#include <asm/pdc.h>
     48#include <linux/uaccess.h>
     49
     50/* The control of the LEDs and LCDs on PARISC-machines have to be done 
     51   completely in software. The necessary calculations are done in a work queue
     52   task which is scheduled regularly, and since the calculations may consume a 
     53   relatively large amount of CPU time, some of the calculations can be 
     54   turned off with the following variables (controlled via procfs) */
     55
     56static int led_type __read_mostly = -1;
     57static unsigned char lastleds;	/* LED state from most recent update */
     58static unsigned int led_heartbeat __read_mostly = 1;
     59static unsigned int led_diskio    __read_mostly = 1;
     60static unsigned int led_lanrxtx   __read_mostly = 1;
     61static char lcd_text[32]          __read_mostly;
     62static char lcd_text_default[32]  __read_mostly;
     63static int  lcd_no_led_support    __read_mostly = 0; /* KittyHawk doesn't support LED on its LCD */
     64
     65
     66static struct workqueue_struct *led_wq;
     67static void led_work_func(struct work_struct *);
     68static DECLARE_DELAYED_WORK(led_task, led_work_func);
     69
     70#if 0
     71#define DPRINTK(x)	printk x
     72#else
     73#define DPRINTK(x)
     74#endif
     75
     76struct lcd_block {
     77	unsigned char command;	/* stores the command byte      */
     78	unsigned char on;	/* value for turning LED on     */
     79	unsigned char off;	/* value for turning LED off    */
     80};
     81
     82/* Structure returned by PDC_RETURN_CHASSIS_INFO */
     83/* NOTE: we use unsigned long:16 two times, since the following member 
     84   lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
     85struct pdc_chassis_lcd_info_ret_block {
     86	unsigned long model:16;		/* DISPLAY_MODEL_XXXX */
     87	unsigned long lcd_width:16;	/* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
     88	unsigned long lcd_cmd_reg_addr;	/* ptr to LCD cmd-register & data ptr for LED */
     89	unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
     90	unsigned int min_cmd_delay;	/* delay in uS after cmd-write (LCD only) */
     91	unsigned char reset_cmd1;	/* command #1 for writing LCD string (LCD only) */
     92	unsigned char reset_cmd2;	/* command #2 for writing LCD string (LCD only) */
     93	unsigned char act_enable;	/* 0 = no activity (LCD only) */
     94	struct lcd_block heartbeat;
     95	struct lcd_block disk_io;
     96	struct lcd_block lan_rcv;
     97	struct lcd_block lan_tx;
     98	char _pad;
     99};
    100
    101
    102/* LCD_CMD and LCD_DATA for KittyHawk machines */
    103#define KITTYHAWK_LCD_CMD  F_EXTEND(0xf0190000UL) /* 64bit-ready */
    104#define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD+1)
    105
    106/* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's 
    107 * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
    108static struct pdc_chassis_lcd_info_ret_block
    109lcd_info __attribute__((aligned(8))) __read_mostly =
    110{
    111	.model =		DISPLAY_MODEL_LCD,
    112	.lcd_width =		16,
    113	.lcd_cmd_reg_addr =	KITTYHAWK_LCD_CMD,
    114	.lcd_data_reg_addr =	KITTYHAWK_LCD_DATA,
    115	.min_cmd_delay =	80,
    116	.reset_cmd1 =		0x80,
    117	.reset_cmd2 =		0xc0,
    118};
    119
    120
    121/* direct access to some of the lcd_info variables */
    122#define LCD_CMD_REG	lcd_info.lcd_cmd_reg_addr	 
    123#define LCD_DATA_REG	lcd_info.lcd_data_reg_addr	 
    124#define LED_DATA_REG	lcd_info.lcd_cmd_reg_addr	/* LASI & ASP only */
    125
    126#define LED_HASLCD 1
    127#define LED_NOLCD  0
    128
    129/* The workqueue must be created at init-time */
    130static int start_task(void) 
    131{	
    132	/* Display the default text now */
    133	if (led_type == LED_HASLCD) lcd_print( lcd_text_default );
    134
    135	/* KittyHawk has no LED support on its LCD */
    136	if (lcd_no_led_support) return 0;
    137
    138	/* Create the work queue and queue the LED task */
    139	led_wq = create_singlethread_workqueue("led_wq");	
    140	queue_delayed_work(led_wq, &led_task, 0);
    141
    142	return 0;
    143}
    144
    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_data(inode));
    172}
    173
    174
    175static ssize_t led_proc_write(struct file *file, const char __user *buf,
    176	size_t count, loff_t *pos)
    177{
    178	void *data = pde_data(file_inode(file));
    179	char *cur, lbuf[32];
    180	int d;
    181
    182	if (!capable(CAP_SYS_ADMIN))
    183		return -EACCES;
    184
    185	if (count >= sizeof(lbuf))
    186		count = sizeof(lbuf)-1;
    187
    188	if (copy_from_user(lbuf, buf, count))
    189		return -EFAULT;
    190	lbuf[count] = 0;
    191
    192	cur = lbuf;
    193
    194	switch ((long)data)
    195	{
    196	case LED_NOLCD:
    197		d = *cur++ - '0';
    198		if (d != 0 && d != 1) goto parse_error;
    199		led_heartbeat = d;
    200
    201		if (*cur++ != ' ') goto parse_error;
    202
    203		d = *cur++ - '0';
    204		if (d != 0 && d != 1) goto parse_error;
    205		led_diskio = d;
    206
    207		if (*cur++ != ' ') goto parse_error;
    208
    209		d = *cur++ - '0';
    210		if (d != 0 && d != 1) goto parse_error;
    211		led_lanrxtx = d;
    212
    213		break;
    214	case LED_HASLCD:
    215		if (*cur && cur[strlen(cur)-1] == '\n')
    216			cur[strlen(cur)-1] = 0;
    217		if (*cur == 0) 
    218			cur = lcd_text_default;
    219		lcd_print(cur);
    220		break;
    221	default:
    222		return 0;
    223	}
    224	
    225	return count;
    226
    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 proc_ops led_proc_ops = {
    234	.proc_open	= led_proc_open,
    235	.proc_read	= seq_read,
    236	.proc_lseek	= seq_lseek,
    237	.proc_release	= single_release,
    238	.proc_write	= led_proc_write,
    239};
    240
    241static int __init led_create_procfs(void)
    242{
    243	struct proc_dir_entry *proc_pdc_root = NULL;
    244	struct proc_dir_entry *ent;
    245
    246	if (led_type == -1) return -1;
    247
    248	proc_pdc_root = proc_mkdir("pdc", NULL);
    249	if (!proc_pdc_root) return -1;
    250
    251	if (!lcd_no_led_support)
    252	{
    253		ent = proc_create_data("led", 0644, proc_pdc_root,
    254					&led_proc_ops, (void *)LED_NOLCD); /* LED */
    255		if (!ent) return -1;
    256	}
    257
    258	if (led_type == LED_HASLCD)
    259	{
    260		ent = proc_create_data("lcd", 0644, proc_pdc_root,
    261					&led_proc_ops, (void *)LED_HASLCD); /* LCD */
    262		if (!ent) return -1;
    263	}
    264
    265	return 0;
    266}
    267#endif
    268
    269/*
    270   ** 
    271   ** led_ASP_driver()
    272   ** 
    273 */
    274#define	LED_DATA	0x01	/* data to shift (0:on 1:off) */
    275#define	LED_STROBE	0x02	/* strobe to clock data */
    276static void led_ASP_driver(unsigned char leds)
    277{
    278	int i;
    279
    280	leds = ~leds;
    281	for (i = 0; i < 8; i++) {
    282		unsigned char value;
    283		value = (leds & 0x80) >> 7;
    284		gsc_writeb( value,		 LED_DATA_REG );
    285		gsc_writeb( value | LED_STROBE,	 LED_DATA_REG );
    286		leds <<= 1;
    287	}
    288}
    289
    290
    291/*
    292   ** 
    293   ** led_LASI_driver()
    294   ** 
    295 */
    296static void led_LASI_driver(unsigned char leds)
    297{
    298	leds = ~leds;
    299	gsc_writeb( leds, LED_DATA_REG );
    300}
    301
    302
    303/*
    304   ** 
    305   ** led_LCD_driver()
    306   **   
    307 */
    308static void led_LCD_driver(unsigned char leds)
    309{
    310	static int i;
    311	static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
    312		LED_LAN_RCV, LED_LAN_TX };
    313	
    314	static struct lcd_block * blockp[4] = {
    315		&lcd_info.heartbeat,
    316		&lcd_info.disk_io,
    317		&lcd_info.lan_rcv,
    318		&lcd_info.lan_tx
    319	};
    320
    321	/* Convert min_cmd_delay to milliseconds */
    322	unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
    323	
    324	for (i=0; i<4; ++i) 
    325	{
    326		if ((leds & mask[i]) != (lastleds & mask[i])) 
    327		{
    328			gsc_writeb( blockp[i]->command, LCD_CMD_REG );
    329			msleep(msec_cmd_delay);
    330			
    331			gsc_writeb( leds & mask[i] ? blockp[i]->on : 
    332					blockp[i]->off, LCD_DATA_REG );
    333			msleep(msec_cmd_delay);
    334		}
    335	}
    336}
    337
    338
    339/*
    340   ** 
    341   ** led_get_net_activity()
    342   ** 
    343   ** calculate if there was TX- or RX-throughput on the network interfaces
    344   ** (analog to dev_get_info() from net/core/dev.c)
    345   **   
    346 */
    347static __inline__ int led_get_net_activity(void)
    348{ 
    349#ifndef CONFIG_NET
    350	return 0;
    351#else
    352	static u64 rx_total_last, tx_total_last;
    353	u64 rx_total, tx_total;
    354	struct net_device *dev;
    355	int retval;
    356
    357	rx_total = tx_total = 0;
    358	
    359	/* we are running as a workqueue task, so we can use an RCU lookup */
    360	rcu_read_lock();
    361	for_each_netdev_rcu(&init_net, dev) {
    362	    const struct rtnl_link_stats64 *stats;
    363	    struct rtnl_link_stats64 temp;
    364	    struct in_device *in_dev = __in_dev_get_rcu(dev);
    365	    if (!in_dev || !in_dev->ifa_list)
    366		continue;
    367	    if (ipv4_is_loopback(in_dev->ifa_list->ifa_local))
    368		continue;
    369	    stats = dev_get_stats(dev, &temp);
    370	    rx_total += stats->rx_packets;
    371	    tx_total += stats->tx_packets;
    372	}
    373	rcu_read_unlock();
    374
    375	retval = 0;
    376
    377	if (rx_total != rx_total_last) {
    378		rx_total_last = rx_total;
    379		retval |= LED_LAN_RCV;
    380	}
    381
    382	if (tx_total != tx_total_last) {
    383		tx_total_last = tx_total;
    384		retval |= LED_LAN_TX;
    385	}
    386
    387	return retval;
    388#endif
    389}
    390
    391
    392/*
    393   ** 
    394   ** led_get_diskio_activity()
    395   ** 
    396   ** calculate if there was disk-io in the system
    397   **   
    398 */
    399static __inline__ int led_get_diskio_activity(void)
    400{	
    401	static unsigned long last_pgpgin, last_pgpgout;
    402	unsigned long events[NR_VM_EVENT_ITEMS];
    403	int changed;
    404
    405	all_vm_events(events);
    406
    407	/* Just use a very simple calculation here. Do not care about overflow,
    408	   since we only want to know if there was activity or not. */
    409	changed = (events[PGPGIN] != last_pgpgin) ||
    410		  (events[PGPGOUT] != last_pgpgout);
    411	last_pgpgin  = events[PGPGIN];
    412	last_pgpgout = events[PGPGOUT];
    413
    414	return (changed ? LED_DISK_IO : 0);
    415}
    416
    417
    418
    419/*
    420   ** led_work_func()
    421   ** 
    422   ** manages when and which chassis LCD/LED gets updated
    423
    424    TODO:
    425    - display load average (older machines like 715/64 have 4 "free" LED's for that)
    426    - optimizations
    427 */
    428
    429#define HEARTBEAT_LEN (HZ*10/100)
    430#define HEARTBEAT_2ND_RANGE_START (HZ*28/100)
    431#define HEARTBEAT_2ND_RANGE_END   (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)
    432
    433#define LED_UPDATE_INTERVAL (1 + (HZ*19/1000))
    434
    435static void led_work_func (struct work_struct *unused)
    436{
    437	static unsigned long last_jiffies;
    438	static unsigned long count_HZ; /* counter in range 0..HZ */
    439	unsigned char currentleds = 0; /* stores current value of the LEDs */
    440
    441	/* exit if not initialized */
    442	if (!led_func_ptr)
    443	    return;
    444
    445	/* increment the heartbeat timekeeper */
    446	count_HZ += jiffies - last_jiffies;
    447	last_jiffies = jiffies;
    448	if (count_HZ >= HZ)
    449	    count_HZ = 0;
    450
    451	if (likely(led_heartbeat))
    452	{
    453		/* flash heartbeat-LED like a real heart
    454		 * (2 x short then a long delay)
    455		 */
    456		if (count_HZ < HEARTBEAT_LEN || 
    457				(count_HZ >= HEARTBEAT_2ND_RANGE_START &&
    458				count_HZ < HEARTBEAT_2ND_RANGE_END)) 
    459			currentleds |= LED_HEARTBEAT;
    460	}
    461
    462	if (likely(led_lanrxtx))  currentleds |= led_get_net_activity();
    463	if (likely(led_diskio))   currentleds |= led_get_diskio_activity();
    464
    465	/* blink LEDs if we got an Oops (HPMC) */
    466	if (unlikely(oops_in_progress)) {
    467		if (boot_cpu_data.cpu_type >= pcxl2) {
    468			/* newer machines don't have loadavg. LEDs, so we
    469			 * let all LEDs blink twice per second instead */
    470			currentleds = (count_HZ <= (HZ/2)) ? 0 : 0xff;
    471		} else {
    472			/* old machines: blink loadavg. LEDs twice per second */
    473			if (count_HZ <= (HZ/2))
    474				currentleds &= ~(LED4|LED5|LED6|LED7);
    475			else
    476				currentleds |= (LED4|LED5|LED6|LED7);
    477		}
    478	}
    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
    497static int led_halt(struct notifier_block *, unsigned long, void *);
    498
    499static struct notifier_block led_notifier = {
    500	.notifier_call = led_halt,
    501};
    502static int notifier_disabled = 0;
    503
    504static 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_delayed_work_sync(&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
    546int __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		/* Skip to register LED in QEMU */
    567		if (running_on_qemu)
    568			return 1;
    569		LED_DATA_REG = data_reg;
    570		led_func_ptr = led_LASI_driver;
    571		printk(KERN_INFO "LED display at %lx registered\n", LED_DATA_REG);
    572		led_type = LED_NOLCD;
    573		break;
    574
    575	case DISPLAY_MODEL_OLD_ASP:
    576		LED_DATA_REG = data_reg;
    577		led_func_ptr = led_ASP_driver;
    578		printk(KERN_INFO "LED (ASP-style) display at %lx registered\n", 
    579		    LED_DATA_REG);
    580		led_type = LED_NOLCD;
    581		break;
    582
    583	default:
    584		printk(KERN_ERR "%s: Wrong LCD/LED model %d !\n",
    585		       __func__, lcd_info.model);
    586		return 1;
    587	}
    588	
    589	/* mark the LCD/LED driver now as initialized and 
    590	 * register to the reboot notifier chain */
    591	initialized++;
    592	register_reboot_notifier(&led_notifier);
    593
    594	/* Ensure the work is queued */
    595	if (led_wq) {
    596		queue_delayed_work(led_wq, &led_task, 0);
    597	}
    598
    599	return 0;
    600}
    601
    602/*
    603   ** register_led_regions()
    604   ** 
    605   ** register_led_regions() registers the LCD/LED regions for /procfs.
    606   ** At bootup - where the initialisation of the LCD/LED normally happens - 
    607   ** not all internal structures of request_region() are properly set up,
    608   ** so that we delay the led-registration until after busdevices_init() 
    609   ** has been executed.
    610   **
    611 */
    612
    613void __init register_led_regions(void)
    614{
    615	switch (lcd_info.model) {
    616	case DISPLAY_MODEL_LCD:
    617		request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
    618		request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
    619		break;
    620	case DISPLAY_MODEL_LASI:
    621	case DISPLAY_MODEL_OLD_ASP:
    622		request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
    623		break;
    624	}
    625}
    626
    627
    628/*
    629   ** 
    630   ** lcd_print()
    631   ** 
    632   ** Displays the given string on the LCD-Display of newer machines.
    633   ** lcd_print() disables/enables the timer-based led work queue to
    634   ** avoid a race condition while writing the CMD/DATA register pair.
    635   **
    636 */
    637int lcd_print( const char *str )
    638{
    639	int i;
    640
    641	if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
    642	    return 0;
    643	
    644	/* temporarily disable the led work task */
    645	if (led_wq)
    646		cancel_delayed_work_sync(&led_task);
    647
    648	/* copy display string to buffer for procfs */
    649	strlcpy(lcd_text, str, sizeof(lcd_text));
    650
    651	/* Set LCD Cursor to 1st character */
    652	gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
    653	udelay(lcd_info.min_cmd_delay);
    654
    655	/* Print the string */
    656	for (i=0; i < lcd_info.lcd_width; i++) {
    657	    if (str && *str)
    658		gsc_writeb(*str++, LCD_DATA_REG);
    659	    else
    660		gsc_writeb(' ', LCD_DATA_REG);
    661	    udelay(lcd_info.min_cmd_delay);
    662	}
    663	
    664	/* re-queue the work */
    665	if (led_wq) {
    666		queue_delayed_work(led_wq, &led_task, 0);
    667	}
    668
    669	return lcd_info.lcd_width;
    670}
    671
    672/*
    673   ** led_init()
    674   ** 
    675   ** led_init() is called very early in the bootup-process from setup.c 
    676   ** and asks the PDC for an usable chassis LCD or LED.
    677   ** If the PDC doesn't return any info, then the LED
    678   ** is detected by lasi.c or asp.c and registered with the
    679   ** above functions lasi_led_init() or asp_led_init().
    680   ** KittyHawk machines have often a buggy PDC, so that
    681   ** we explicitly check for those machines here.
    682 */
    683
    684int __init led_init(void)
    685{
    686	struct pdc_chassis_info chassis_info;
    687	int ret;
    688
    689	snprintf(lcd_text_default, sizeof(lcd_text_default),
    690		"Linux %s", init_utsname()->release);
    691
    692	/* Work around the buggy PDC of KittyHawk-machines */
    693	switch (CPU_HVERSION) {
    694	case 0x580:		/* KittyHawk DC2-100 (K100) */
    695	case 0x581:		/* KittyHawk DC3-120 (K210) */
    696	case 0x582:		/* KittyHawk DC3 100 (K400) */
    697	case 0x583:		/* KittyHawk DC3 120 (K410) */
    698	case 0x58B:		/* KittyHawk DC2 100 (K200) */
    699		printk(KERN_INFO "%s: KittyHawk-Machine (hversion 0x%x) found, "
    700				"LED detection skipped.\n", __FILE__, CPU_HVERSION);
    701		lcd_no_led_support = 1;
    702		goto found;	/* use the preinitialized values of lcd_info */
    703	}
    704
    705	/* initialize the struct, so that we can check for valid return values */
    706	lcd_info.model = DISPLAY_MODEL_NONE;
    707	chassis_info.actcnt = chassis_info.maxcnt = 0;
    708
    709	ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
    710	if (ret == PDC_OK) {
    711		DPRINTK((KERN_INFO "%s: chassis info: model=%d (%s), "
    712			 "lcd_width=%d, cmd_delay=%u,\n"
    713			 "%s: sizecnt=%d, actcnt=%ld, maxcnt=%ld\n",
    714		         __FILE__, lcd_info.model,
    715			 (lcd_info.model==DISPLAY_MODEL_LCD) ? "LCD" :
    716			  (lcd_info.model==DISPLAY_MODEL_LASI) ? "LED" : "unknown",
    717			 lcd_info.lcd_width, lcd_info.min_cmd_delay,
    718			 __FILE__, sizeof(lcd_info), 
    719			 chassis_info.actcnt, chassis_info.maxcnt));
    720		DPRINTK((KERN_INFO "%s: cmd=%p, data=%p, reset1=%x, reset2=%x, act_enable=%d\n",
    721			__FILE__, lcd_info.lcd_cmd_reg_addr, 
    722			lcd_info.lcd_data_reg_addr, lcd_info.reset_cmd1,  
    723			lcd_info.reset_cmd2, lcd_info.act_enable ));
    724	
    725		/* check the results. Some machines have a buggy PDC */
    726		if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
    727			goto not_found;
    728
    729		switch (lcd_info.model) {
    730		case DISPLAY_MODEL_LCD:		/* LCD display */
    731			if (chassis_info.actcnt < 
    732				offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
    733				goto not_found;
    734			if (!lcd_info.act_enable) {
    735				DPRINTK((KERN_INFO "PDC prohibited usage of the LCD.\n"));
    736				goto not_found;
    737			}
    738			break;
    739
    740		case DISPLAY_MODEL_NONE:	/* no LED or LCD available */
    741			printk(KERN_INFO "PDC reported no LCD or LED.\n");
    742			goto not_found;
    743
    744		case DISPLAY_MODEL_LASI:	/* Lasi style 8 bit LED display */
    745			if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
    746				goto not_found;
    747			break;
    748
    749		default:
    750			printk(KERN_WARNING "PDC reported unknown LCD/LED model %d\n",
    751			       lcd_info.model);
    752			goto not_found;
    753		} /* switch() */
    754
    755found:
    756		/* register the LCD/LED driver */
    757		register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
    758		return 0;
    759
    760	} else { /* if() */
    761		DPRINTK((KERN_INFO "pdc_chassis_info call failed with retval = %d\n", ret));
    762	}
    763
    764not_found:
    765	lcd_info.model = DISPLAY_MODEL_NONE;
    766	return 1;
    767}
    768
    769static void __exit led_exit(void)
    770{
    771	unregister_reboot_notifier(&led_notifier);
    772	return;
    773}
    774
    775#ifdef CONFIG_PROC_FS
    776module_init(led_create_procfs)
    777#endif