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

/*
 *    Chassis LCD/LED driver for HP-PARISC workstations
 *
 *      (c) Copyright 2000 Red Hat Software
 *      (c) Copyright 2000 Helge Deller <[e-mail]>
 *      (c) Copyright 2001-2002 Helge Deller <[e-mail]>
 *      (c) Copyright 2001 Randolph Chung <[e-mail]>
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License as published by
 *      the Free Software Foundation; either version 2 of the License, or
 *      (at your option) any later version.
 *
 * TODO:
 *	- speed-up calculations with inlined assembler
 *	- interface to write to second row of LCD from /proc
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/stddef.h>	/* for offsetof() */
#include <linux/init.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/bitops.h>
#include <linux/version.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/reboot.h>
#include <linux/proc_fs.h>
#include <linux/ctype.h>
#include <asm/io.h>
#include <asm/gsc.h>
#include <asm/processor.h>
#include <asm/hardware.h>
#include <asm/param.h>		/* HZ */
#include <asm/led.h>
#include <asm/pdc.h>
#include <asm/uaccess.h>

/* The control of the LEDs and LCDs on PARISC-machines have to be done 
   completely in software. The necessary calculations are done in a tasklet
   which is scheduled at every timer interrupt and since the calculations 
   may consume relatively much CPU-time some of the calculations can be 
   turned off with the following variables (controlled via procfs) */

static int led_type = -1;
static int led_heartbeat = 1;
static int led_diskio = 1;
static int led_lanrxtx = 1;
static char lcd_text[32];

#if 0
#define DPRINTK(x)	printk x
#else
#define DPRINTK(x)
#endif


#define CALC_ADD(val, comp, add) \
 (val<=(comp/8) ? add/16 : val<=(comp/4) ? add/8 : val<=(comp/2) ? add/4 : add)


struct lcd_block {
	unsigned char command;	/* stores the command byte      */
	unsigned char on;	/* value for turning LED on     */
	unsigned char off;	/* value for turning LED off    */
};

/* Structure returned by PDC_RETURN_CHASSIS_INFO */
/* NOTE: we use unsigned long:16 two times, since the following member 
   lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
struct pdc_chassis_lcd_info_ret_block {
	unsigned long model:16;		/* DISPLAY_MODEL_XXXX */
	unsigned long lcd_width:16;	/* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
	char *lcd_cmd_reg_addr;		/* ptr to LCD cmd-register & data ptr for LED */
	char *lcd_data_reg_addr;	/* ptr to LCD data-register (LCD only) */
	unsigned int min_cmd_delay;	/* delay in uS after cmd-write (LCD only) */
	unsigned char reset_cmd1;	/* command #1 for writing LCD string (LCD only) */
	unsigned char reset_cmd2;	/* command #2 for writing LCD string (LCD only) */
	unsigned char act_enable;	/* 0 = no activity (LCD only) */
	struct lcd_block heartbeat;
	struct lcd_block disk_io;
	struct lcd_block lan_rcv;
	struct lcd_block lan_tx;
	char _pad;
};


/* LCD_CMD and LCD_DATA for KittyHawk machines */
#define KITTYHAWK_LCD_CMD  (0xfffffffff0190000UL) /* 64bit-ready */
#define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD+1)

/* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's 
 * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
static struct pdc_chassis_lcd_info_ret_block
lcd_info __attribute__((aligned(8))) =
{
      model:		DISPLAY_MODEL_LCD,
      lcd_width:	16,
      lcd_cmd_reg_addr:	(char *) KITTYHAWK_LCD_CMD,
      lcd_data_reg_addr:(char *) KITTYHAWK_LCD_DATA,
      min_cmd_delay:	40,
      reset_cmd1:	0x80,
      reset_cmd2:	0xc0,
};


/* direct access to some of the lcd_info variables */
#define LCD_CMD_REG	lcd_info.lcd_cmd_reg_addr	 
#define LCD_DATA_REG	lcd_info.lcd_data_reg_addr	 
#define LED_DATA_REG	lcd_info.lcd_cmd_reg_addr	/* LASI & ASP only */


/* ptr to LCD/LED-specific function */
static void (*led_func_ptr) (unsigned char);

#define LED_HASLCD 1
#define LED_NOLCD  0
#ifdef CONFIG_PROC_FS
static int led_proc_read(char *page, char **start, off_t off, int count, 
	int *eof, void *data)
{
	char *out = page;
	int len;

	switch ((long)data)
	{
	case LED_NOLCD:
		out += sprintf(out, "Heartbeat: %d\n", led_heartbeat);
		out += sprintf(out, "Disk IO: %d\n", led_diskio);
		out += sprintf(out, "LAN Rx/Tx: %d\n", led_lanrxtx);
		break;
	case LED_HASLCD:
		out += sprintf(out, "%s\n", lcd_text);
		break;
	default:
		*eof = 1;
		return 0;
	}

	len = out - page - off;
	if (len < count) {
		*eof = 1;
		if (len <= 0) return 0;
	} else {
		len = count;
	}
	*start = page + off;
	return len;
}

static int led_proc_write(struct file *file, const char *buf, 
	unsigned long count, void *data)
{
	char *cur, lbuf[count];
	int d;

	if (!capable(CAP_SYS_ADMIN))
		return -EACCES;

	memset(lbuf, 0, count);

	copy_from_user(lbuf, buf, count);
	cur = lbuf;

	/* skip initial spaces */
	while (*cur && isspace(*cur))
	{
		cur++;
	}

	switch ((long)data)
	{
	case LED_NOLCD:
		d = *cur++ - '0';
		if (d != 0 && d != 1) goto parse_error;
		led_heartbeat = d;

		if (*cur++ != ' ') goto parse_error;

		d = *cur++ - '0';
		if (d != 0 && d != 1) goto parse_error;
		led_diskio = d;

		if (*cur++ != ' ') goto parse_error;

		d = *cur++ - '0';
		if (d != 0 && d != 1) goto parse_error;
		led_lanrxtx = d;

		break;
	case LED_HASLCD:
		if (*cur == 0) 
		{
			/* reset to default */
			lcd_print("Linux " UTS_RELEASE);
		}
		else
		{
			/* chop off trailing \n.. if the user gives multiple
			 * \n then it's all their fault.. */
			if (*cur && cur[strlen(cur)-1] == '\n')
				cur[strlen(cur)-1] = 0;
			lcd_print(cur);
		}
		break;
	default:
		return 0;
	}
	
	return count;

parse_error:
	if ((long)data == LED_NOLCD)
		printk(KERN_CRIT "Parse error: expect \"n n n\" (n == 0 or 1) for heartbeat,\ndisk io and lan tx/rx indicators\n");
	return -EINVAL;
}

static int __init led_create_procfs(void)
{
	struct proc_dir_entry *proc_pdc_root = NULL;
	struct proc_dir_entry *ent;

	if (led_type == -1) return -1;

	proc_pdc_root = proc_mkdir("pdc", 0);
	if (!proc_pdc_root) return -1;
	proc_pdc_root->owner = THIS_MODULE;
	ent = create_proc_entry("led", S_IFREG|S_IRUGO|S_IWUSR, proc_pdc_root);
	if (!ent) return -1;
	ent->nlink = 1;
	ent->data = (void *)LED_NOLCD; /* LED */
	ent->read_proc = led_proc_read;
	ent->write_proc = led_proc_write;
	ent->owner = THIS_MODULE;

	if (led_type == LED_HASLCD)
	{
		ent = create_proc_entry("lcd", S_IFREG|S_IRUGO|S_IWUSR, proc_pdc_root);
		if (!ent) return -1;
		ent->nlink = 1;
		ent->data = (void *)LED_HASLCD; /* LCD */
		ent->read_proc = led_proc_read;
		ent->write_proc = led_proc_write;
		ent->owner = THIS_MODULE;
	}

	return 0;
}
#endif

/*
   ** 
   ** led_ASP_driver()
   ** 
 */
#define	LED_DATA	0x01	/* data to shift (0:on 1:off) */
#define	LED_STROBE	0x02	/* strobe to clock data */
static void led_ASP_driver(unsigned char leds)
{
	int i;

	leds = ~leds;
	for (i = 0; i < 8; i++) {
		unsigned char value;
		value = (leds & 0x80) >> 7;
		gsc_writeb( value,		 LED_DATA_REG );
		gsc_writeb( value | LED_STROBE,	 LED_DATA_REG );
		leds <<= 1;
	}
}


/*
   ** 
   ** led_LASI_driver()
   ** 
 */
static void led_LASI_driver(unsigned char leds)
{
	leds = ~leds;
	gsc_writeb( leds, LED_DATA_REG );
}


/*
   ** 
   ** led_LCD_driver()
   ** 
   ** The logic of the LCD driver is, that we write at every scheduled call
   ** only to one of LCD_CMD_REG _or_ LCD_DATA_REG - registers.
   ** That way we don't need to let this tasklet busywait for min_cmd_delay
   ** milliseconds.
   **
   ** TODO: check the value of "min_cmd_delay" against the value of HZ.
   **   
 */
static void led_LCD_driver(unsigned char leds)
{
	static int last_index;	/* 0:heartbeat, 1:disk, 2:lan_in, 3:lan_out */
	static int last_was_cmd;/* 0: CMD was written last, 1: DATA was last */
	struct lcd_block *block_ptr;
	int value;

	switch (last_index) {
	    case 0:	block_ptr = &lcd_info.heartbeat;
			value = leds & LED_HEARTBEAT;
			break;
	    case 1:	block_ptr = &lcd_info.disk_io;
			value = leds & LED_DISK_IO;
			break;					
	    case 2:	block_ptr = &lcd_info.lan_rcv;
			value = leds & LED_LAN_RCV;
			break;					
	    case 3:	block_ptr = &lcd_info.lan_tx;
			value = leds & LED_LAN_TX;
			break;
	    default:	/* should never happen: */
			return;
	}

	if (last_was_cmd) {
	    /* write the value to the LCD data port */
    	    gsc_writeb( value ? block_ptr->on : block_ptr->off, LCD_DATA_REG );
	} else {
	    /* write the command-byte to the LCD command register */
    	    gsc_writeb( block_ptr->command, LCD_CMD_REG );
	}    
	
	/* now update the vars for the next interrupt iteration */ 
	if (++last_was_cmd == 2) { /* switch between cmd & data */
	    last_was_cmd = 0;
	    if (++last_index == 4) 
		last_index = 0;	 /* switch back to heartbeat index */
	}
}


/*
   ** 
   ** led_get_net_stats()
   ** 
   ** calculate the TX- & RX-troughput on the network interfaces in
   ** the system for usage in the LED code
   **
   ** (analog to dev_get_info() from net/core/dev.c)
   **   
 */
static unsigned long led_net_rx_counter, led_net_tx_counter;

static void led_get_net_stats(int addvalue)
{
	static unsigned long rx_total_last, tx_total_last;
	unsigned long rx_total, tx_total;
	struct net_device *dev;
	struct net_device_stats *stats;

	rx_total = tx_total = 0;
	
	/* we are running as a tasklet, so locking dev_base 
	 * for reading should be OK */
	read_lock(&dev_base_lock);
	for (dev = dev_base; dev != NULL; dev = dev->next) {
	    if (dev->get_stats) { 
	        stats = dev->get_stats(dev);
		rx_total += stats->rx_packets;
		tx_total += stats->tx_packets;
	    }
	}
	read_unlock(&dev_base_lock);

	rx_total -= rx_total_last;
	tx_total -= tx_total_last;
	
	if (rx_total)
	    led_net_rx_counter += CALC_ADD(rx_total, tx_total, addvalue);

	if (tx_total)
	    led_net_tx_counter += CALC_ADD(tx_total, rx_total, addvalue);
        
	rx_total_last += rx_total;
        tx_total_last += tx_total;
}