led.c

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/*
 *    Chassis LCD/LED driver for HP-PARISC workstations
 *
 *      (c) Copyright 2000 Red Hat Software
 *      (c) Copyright 2000 Helge Deller <[e-mail]>
 *      (c) Copyright 2001-2005 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 (if technically possible)
 *
 * Changes:
 *      - Audit copy_from_user in led_proc_write.
 *                                Daniele Bellucci <[e-mail]>
 *	- Switch from using a tasklet to a work queue, so the led_LCD_driver
 *	  	can sleep.
 *	  			  David Pye <[e-mail]>
 */

#include <linux/module.h>
#include <linux/stddef.h>	/* for offsetof() */
#include <linux/init.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/utsname.h>
#include <linux/capability.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/in.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/reboot.h>
#include <linux/proc_fs.h>
#include <linux/ctype.h>
#include <linux/blkdev.h>
#include <linux/workqueue.h>
#include <linux/rcupdate.h>
#include <asm/io.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 work queue
   task which is scheduled regularly, and since the calculations may consume a 
   relatively large amount of CPU time, some of the calculations can be 
   turned off with the following variables (controlled via procfs) */

static int led_type __read_mostly = -1;
static unsigned char lastleds;	/* LED state from most recent update */
static unsigned int led_heartbeat __read_mostly = 1;
static unsigned int led_diskio    __read_mostly = 1;
static unsigned int led_lanrxtx   __read_mostly = 1;
static char lcd_text[32]          __read_mostly;
static char lcd_text_default[32]  __read_mostly;


static struct workqueue_struct *led_wq;
static void led_work_func(struct work_struct *);
static DECLARE_DELAYED_WORK(led_task, led_work_func);

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

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) */
	unsigned long lcd_cmd_reg_addr;	/* ptr to LCD cmd-register & data ptr for LED */
	unsigned long 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  F_EXTEND(0xf0190000UL) /* 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))) __read_mostly =
{
	.model =		DISPLAY_MODEL_LCD,
	.lcd_width =		16,
	.lcd_cmd_reg_addr =	KITTYHAWK_LCD_CMD,
	.lcd_data_reg_addr =	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 */

#define LED_HASLCD 1
#define LED_NOLCD  0

/* The workqueue must be created at init-time */
static int start_task(void) 
{	
	/* Display the default text now */
	if (led_type == LED_HASLCD) lcd_print( lcd_text_default );

	/* Create the work queue and queue the LED task */
	led_wq = create_singlethread_workqueue("led_wq");	
	queue_delayed_work(led_wq, &led_task, 0);

	return 0;
}

device_initcall(start_task);

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

#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 + 1];
	int d;

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

	memset(lbuf, 0, count + 1);

	if (copy_from_user(lbuf, buf, count))
		return -EFAULT;

	cur = lbuf;

	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 && cur[strlen(cur)-1] == '\n')
			cur[strlen(cur)-1] = 0;
		if (*cur == 0) 
			cur = lcd_text_default;
		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->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->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()
   **   
 */
static void led_LCD_driver(unsigned char leds)
{
	static int i;
	static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
		LED_LAN_RCV, LED_LAN_TX };
	
	static struct lcd_block * blockp[4] = {
		&lcd_info.heartbeat,
		&lcd_info.disk_io,
		&lcd_info.lan_rcv,
		&lcd_info.lan_tx
	};

	/* Convert min_cmd_delay to milliseconds */
	unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);
	
	for (i=0; i<4; ++i) 
	{
		if ((leds & mask[i]) != (lastleds & mask[i])) 
		{
			gsc_writeb( blockp[i]->command, LCD_CMD_REG );
			msleep(msec_cmd_delay);
			
			gsc_writeb( leds & mask[i] ? blockp[i]->on : 
					blockp[i]->off, LCD_DATA_REG );
			msleep(msec_cmd_delay);
		}
	}
}


/*
   ** 
   ** led_get_net_activity()
   ** 
   ** calculate if there was TX- or RX-throughput on the network interfaces
   ** (analog to dev_get_info() from net/core/dev.c)
   **   
 */
static __inline__ int led_get_net_activity(void)
{ 
#ifndef CONFIG_NET
	return 0;
#else
	static unsigned long rx_total_last, tx_total_last;
	unsigned long rx_total, tx_total;
	struct net_device *dev;
	int retval;

	rx_total = tx_total = 0;
	
	/* we are running as a workqueue task, so locking dev_base 
	 * for reading should be OK */
	read_lock(&dev_base_lock);
	rcu_read_lock();
	for_each_netdev(&init_net, dev) {
	    struct net_device_stats *stats;
	    struct in_device *in_dev = __in_dev_get_rcu(dev);
	    if (!in_dev || !in_dev->ifa_list)
		continue;
	    if (LOOPBACK(in_dev->ifa_list->ifa_local))
		continue;
	    stats = dev->get_stats(dev);
	    rx_total += stats->rx_packets;
	    tx_total += stats->tx_packets;
	}
	rcu_read_unlock();
	read_unlock(&dev_base_lock);

	retval = 0;

	if (rx_total != rx_total_last) {
		rx_total_last = rx_total;
		retval |= LED_LAN_RCV;
	}