led.c

来自「linux 内核源代码」· C语言 代码 · 共 764 行 · 第 1/2 页

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

	return retval;
#endif
}


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

	all_vm_events(events);

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

	return (changed ? LED_DISK_IO : 0);
}



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

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

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

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

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

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

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

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

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

	/* blink all LEDs twice a second if we got an Oops (HPMC) */
	if (unlikely(oops_in_progress)) 
		currentleds = (count_HZ<=(HZ/2)) ? 0 : 0xff;

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

	queue_delayed_work(led_wq, &led_task, LED_UPDATE_INTERVAL);
}

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

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

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

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

	if (notifier_disabled)
		return NOTIFY_OK;

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

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

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

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

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

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

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

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

	return 0;
}

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

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


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

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

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

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

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

	return lcd_info.lcd_width;
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

#ifdef CONFIG_PROC_FS
module_init(led_create_procfs)
#endif