led.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

/*
   ** 
   ** led_get_diskio_stats()
   ** 
   ** calculate the disk-io througput in the system
   ** (analog to linux/fs/proc/proc_misc.c)
   **   
 */
static unsigned long led_diskio_counter;

static void led_get_diskio_stats(int addvalue)
{	
	static unsigned int diskio_total_last, diskio_max;
	int major, disk, total;
	
	total = 0;
	for (major = 0; major < DK_MAX_MAJOR; major++) {
	    for (disk = 0; disk < DK_MAX_DISK; disk++)
		total += kstat.dk_drive[major][disk];
	}
	total -= diskio_total_last;
	
	if (total) {
	    if (total >= diskio_max) {
		led_diskio_counter += addvalue;
	        diskio_max = total; /* new maximum value found */ 
	    } else
		led_diskio_counter += CALC_ADD(total, diskio_max, addvalue);
	}
	
	diskio_total_last += total; 
}



/*
   ** led_tasklet_func()
   ** 
   ** is scheduled at every timer interrupt from time.c and
   ** updates the chassis LCD/LED 

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

static unsigned char currentleds;	/* stores current value of the LEDs */

#define HEARTBEAT_LEN (HZ*6/100)
#define HEARTBEAT_2ND_RANGE_START (HZ*22/100)
#define HEARTBEAT_2ND_RANGE_END   (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)

static void led_tasklet_func(unsigned long unused)
{
	static unsigned int count, count_HZ;
	static unsigned char lastleds;

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

	/* increment the local counters */
	++count;
	if (++count_HZ == HZ)
	    count_HZ = 0;

	if (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;
		else
		    currentleds &= ~LED_HEARTBEAT;
	}

	/* gather network and diskio statistics and flash LEDs respectively */

	if (led_lanrxtx)
	{
		if ((count & 31) == 0)
			led_get_net_stats(30);

		if (led_net_rx_counter) {
			led_net_rx_counter--;
			currentleds |= LED_LAN_RCV;
		}
		else    
			currentleds &= ~LED_LAN_RCV;

		if (led_net_tx_counter) {
			led_net_tx_counter--;
			currentleds |= LED_LAN_TX;
		}
		else    
			currentleds &= ~LED_LAN_TX;
	}

	if (led_diskio)
	{
		/* avoid to calculate diskio-stats at same irq as netio-stats ! */
		if ((count & 31) == 15) 
			led_get_diskio_stats(30);

		if (led_diskio_counter) {
			led_diskio_counter--;
			currentleds |= LED_DISK_IO;
		}
		else    
			currentleds &= ~LED_DISK_IO;
	}

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

/* main led tasklet struct (scheduled from time.c) */
DECLARE_TASKLET_DISABLED(led_tasklet, led_tasklet_func, 0);


/*
   ** 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 led_halt(struct notifier_block *nb, unsigned long event, void *buf) 
{
	char *txt;
	
	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;
	}
	
	/* completely stop the LED/LCD tasklet */
	tasklet_disable(&led_tasklet);

	if (lcd_info.model == DISPLAY_MODEL_LCD)
		lcd_print(txt);
	else
		if (led_func_ptr)
			led_func_ptr(0xff); /* turn all LEDs ON */
	
	unregister_reboot_notifier(&led_notifier);
	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, char *cmd_reg, char *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) ? NULL : cmd_reg;

	switch (lcd_info.model) {
	case DISPLAY_MODEL_LCD:
		LCD_DATA_REG = data_reg;
		printk(KERN_INFO "LCD display at %p,%p registered\n", 
			LCD_CMD_REG , LCD_DATA_REG);
		led_func_ptr = led_LCD_driver;
		lcd_print( "Linux " UTS_RELEASE );
		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 %p 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 %p 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);

	/* start the led tasklet for the first time */
	tasklet_enable(&led_tasklet);
	
	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 the timer-based led tasklet during its 
   ** execution and enables it afterwards again.
   **
 */
int lcd_print( char *str )
{
	int i;

	if (!led_func_ptr || lcd_info.model != DISPLAY_MODEL_LCD)
	    return 0;
	
	/* temporarily disable the led tasklet */
	tasklet_disable(&led_tasklet);

	/* copy display string to buffer for procfs */
	strncpy(lcd_text, str, sizeof(lcd_text)-1);
	
	/* 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-enable the led tasklet */
	tasklet_enable(&led_tasklet);

	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;

	/* 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;

	if ((ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info))) == 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;
}

#ifdef CONFIG_PROC_FS
module_init(led_create_procfs)
#endif