comx.c

自己根据lkd和情境分析

/*
 * Device driver framework for the COMX line of synchronous serial boards
 * 
 * for Linux kernel 2.2.X
 *
 * Original authors:  Arpad Bakay <[e-mail]>,
 *                    Peter Bajan <[e-mail]>,
 * Previous maintainer: Tivadar Szemethy <[e-mail]>
 * Current maintainer: Gergely Madarasz <[e-mail]>
 *
 * Copyright (C) 1995-1999 ITConsult-Pro Co.
 *
 * Contributors:
 * Arnaldo Carvalho de Melo <[e-mail]> (0.85)
 *
 * 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.
 *
 * Version 0.80 (99/06/11):
 *		- clean up source code (playing a bit of indent)
 *		- port back to kernel, add support for non-module versions
 *		- add support for board resets when channel protocol is down
 *		- reset the device structure after protocol exit
 *		  the syncppp driver needs it
 *		- add support for /proc/comx/protocols and 
 *		  /proc/comx/boardtypes
 *
 * Version 0.81 (99/06/21):
 *		- comment out the board reset support code, the locomx
 *		  driver seems not buggy now
 *		- printk() levels fixed
 *
 * Version 0.82 (99/07/08):
 *		- Handle stats correctly if the lowlevel driver is
 *		  is not a comx one (locomx - z85230)
 *
 * Version 0.83 (99/07/15):
 *		- reset line_status when interface is down
 *
 * Version 0.84 (99/12/01):
 *		- comx_status should not check for IFF_UP (to report
 *		  line status from dev->open())
 *
 * Version 0.85 (00/08/15):
 * 		- resource release on failure in comx_mkdir
 * 		- fix return value on failure at comx_write_proc
 *
 * Changed      (00/10/29, Henner Eisen):
 * 		- comx_rx() / comxlapb_data_indication() return status.
 */

#define VERSION "0.85"

#include <linux/config.h>
#include <linux/module.h>
#include <linux/version.h>

#include <linux/types.h>
#include <linux/sched.h>
#include <linux/netdevice.h>
#include <linux/proc_fs.h>
#include <asm/uaccess.h>
#include <linux/ctype.h>
#include <linux/init.h>

#ifdef CONFIG_KMOD
#include <linux/kmod.h>
#endif

#ifndef CONFIG_PROC_FS
#error For now, COMX really needs the /proc filesystem
#endif

#include <net/syncppp.h>
#include "comx.h"

MODULE_AUTHOR("Gergely Madarasz <[e-mail]>");
MODULE_DESCRIPTION("Common code for the COMX synchronous serial adapters");
MODULE_LICENSE("GPL");

extern int comx_hw_comx_init(void);
extern int comx_hw_locomx_init(void);
extern int comx_hw_mixcom_init(void);
extern int comx_proto_hdlc_init(void);
extern int comx_proto_ppp_init(void);
extern int comx_proto_syncppp_init(void);
extern int comx_proto_lapb_init(void);
extern int comx_proto_fr_init(void);

static struct comx_hardware *comx_channels = NULL;
static struct comx_protocol *comx_lines = NULL;

static int comx_mkdir(struct inode *, struct dentry *, int);
static int comx_rmdir(struct inode *, struct dentry *);
static struct dentry *comx_lookup(struct inode *, struct dentry *);

static struct inode_operations comx_root_inode_ops = {
	lookup:	comx_lookup,
	mkdir: comx_mkdir,
	rmdir: comx_rmdir,
};

static int comx_delete_dentry(struct dentry *dentry);
static struct proc_dir_entry *create_comx_proc_entry(char *name, int mode,
	int size, struct proc_dir_entry *dir);

static struct dentry_operations comx_dentry_operations = {
	d_delete:	comx_delete_dentry,
};


static struct proc_dir_entry * comx_root_dir;

struct comx_debugflags_struct	comx_debugflags[] = {
	{ "comx_rx",		DEBUG_COMX_RX		},
	{ "comx_tx", 		DEBUG_COMX_TX		},
	{ "hw_tx",		DEBUG_HW_TX		},
	{ "hw_rx", 		DEBUG_HW_RX		},
	{ "hdlc_keepalive",	DEBUG_HDLC_KEEPALIVE	},
	{ "comxppp",		DEBUG_COMX_PPP		},
	{ "comxlapb",		DEBUG_COMX_LAPB		},
	{ "dlci",		DEBUG_COMX_DLCI		},
	{ NULL,			0			} 
};


int comx_debug(struct net_device *dev, char *fmt, ...)
{
	struct comx_channel *ch = dev->priv;
	char *page,*str;
	va_list args;
	int len;

	if (!ch->debug_area) return 0;

	if (!(page = (char *)__get_free_page(GFP_ATOMIC))) return -ENOMEM;

	va_start(args, fmt);
	len = vsprintf(str = page, fmt, args);
	va_end(args);

	if (len >= PAGE_SIZE) {
		printk(KERN_ERR "comx_debug: PANIC! len = %d !!!\n", len);
		free_page((unsigned long)page);
		return -EINVAL;
	}

	while (len) {
		int to_copy;
		int free = (ch->debug_start - ch->debug_end + ch->debug_size) 
			% ch->debug_size;

		to_copy = min_t(int, free ? free : ch->debug_size, 
			      min_t(int, ch->debug_size - ch->debug_end, len));
		memcpy(ch->debug_area + ch->debug_end, str, to_copy);
		str += to_copy;
		len -= to_copy;
		ch->debug_end = (ch->debug_end + to_copy) % ch->debug_size;
		if (ch->debug_start == ch->debug_end) // Full ? push start away
			ch->debug_start = (ch->debug_start + len + 1) % 
					ch->debug_size;
		ch->debug_file->size = (ch->debug_end - ch->debug_start +
					ch->debug_size) % ch->debug_size;
	} 

	free_page((unsigned long)page);
	return 0;
}

int comx_debug_skb(struct net_device *dev, struct sk_buff *skb, char *msg)
{
	struct comx_channel *ch = dev->priv;

	if (!ch->debug_area) return 0;
	if (!skb) comx_debug(dev, "%s: %s NULL skb\n\n", dev->name, msg);
	if (!skb->len) comx_debug(dev, "%s: %s empty skb\n\n", dev->name, msg);

	return comx_debug_bytes(dev, skb->data, skb->len, msg);
}

int comx_debug_bytes(struct net_device *dev, unsigned char *bytes, int len, 
		char *msg)
{
	int pos = 0;
	struct comx_channel *ch = dev->priv;

	if (!ch->debug_area) return 0;

	comx_debug(dev, "%s: %s len %d\n", dev->name, msg, len);

	while (pos != len) {
		char line[80];
		int i = 0;

		memset(line, 0, 80);
		sprintf(line,"%04d ", pos);
		do {
			sprintf(line + 5 + (pos % 16) * 3, "%02x", bytes[pos]);
			sprintf(line + 60 + (pos % 16), "%c", 
				isprint(bytes[pos]) ? bytes[pos] : '.');
			pos++;
		} while (pos != len && pos % 16);

		while ( i++ != 78 ) if (line[i] == 0) line[i] = ' ';
		line[77] = '\n';
		line[78] = 0;
	
		comx_debug(dev, "%s", line);
	}
	comx_debug(dev, "\n");
	return 0;
}

static void comx_loadavg_timerfun(unsigned long d)
{
	struct net_device *dev = (struct net_device *)d;
	struct comx_channel *ch = dev->priv;

	ch->avg_bytes[ch->loadavg_counter] = ch->current_stats->rx_bytes;
	ch->avg_bytes[ch->loadavg_counter + ch->loadavg_size] = 
		ch->current_stats->tx_bytes;

	ch->loadavg_counter = (ch->loadavg_counter + 1) % ch->loadavg_size;

	mod_timer(&ch->loadavg_timer,jiffies + HZ * ch->loadavg[0]);
}

#if 0
static void comx_reset_timerfun(unsigned long d)
{ 
	struct net_device *dev = (struct net_device *)d;
	struct comx_channel *ch = dev->priv;

	if(!(ch->line_status & (PROTO_LOOP | PROTO_UP))) {
		if(test_and_set_bit(0,&ch->reset_pending) && ch->HW_reset) {
			ch->HW_reset(dev);
		}
	}

	mod_timer(&ch->reset_timer, jiffies + HZ * ch->reset_timeout);
}
#endif                                            

static int comx_open(struct net_device *dev)
{
	struct comx_channel *ch = dev->priv;
	struct proc_dir_entry *comxdir = ch->procdir->subdir;
	int ret=0;

	if (!ch->protocol || !ch->hardware) return -ENODEV;

	if ((ret = ch->HW_open(dev))) return ret;
	if ((ret = ch->LINE_open(dev))) { 
		ch->HW_close(dev); 
		return ret; 
	};

	for (; comxdir ; comxdir = comxdir->next) {
		if (strcmp(comxdir->name, FILENAME_HARDWARE) == 0 ||
		   strcmp(comxdir->name, FILENAME_PROTOCOL) == 0)
			comxdir->mode = S_IFREG | 0444;
	}

#if 0
	ch->reset_pending = 1;
	ch->reset_timeout = 30;
	ch->reset_timer.function = comx_reset_timerfun;
	ch->reset_timer.data = (unsigned long)dev;
	ch->reset_timer.expires = jiffies + HZ * ch->reset_timeout;
	add_timer(&ch->reset_timer);
#endif

	return 0;
}

static int comx_close(struct net_device *dev)
{
	struct comx_channel *ch = dev->priv;
	struct proc_dir_entry *comxdir = ch->procdir->subdir;
	int ret = -ENODEV;

	if (test_and_clear_bit(0, &ch->lineup_pending)) {
		del_timer(&ch->lineup_timer);
	}

#if 0	
	del_timer(&ch->reset_timer);
#endif

	if (ch->init_status & LINE_OPEN && ch->protocol && ch->LINE_close) {
		ret = ch->LINE_close(dev);
	}

	if (ret) return ret;

	if (ch->init_status & HW_OPEN && ch->hardware && ch->HW_close) {
		ret = ch->HW_close(dev);
	}
	
	ch->line_status=0;

	for (; comxdir ; comxdir = comxdir->next) {
		if (strcmp(comxdir->name, FILENAME_HARDWARE) == 0 ||
		    strcmp(comxdir->name, FILENAME_PROTOCOL) == 0)
			comxdir->mode = S_IFREG | 0644;
	}

	return ret;
}

void comx_status(struct net_device *dev, int status)
{
	struct comx_channel *ch = dev->priv;

#if 0
	if(status & (PROTO_UP | PROTO_LOOP)) {
		clear_bit(0,&ch->reset_pending);
	}
#endif

	printk(KERN_NOTICE "Interface %s: modem status %s, line protocol %s\n",
		    dev->name, status & LINE_UP ? "UP" : "DOWN", 
		    status & PROTO_LOOP ? "LOOP" : status & PROTO_UP ? 
		    "UP" : "DOWN");
	
	ch->line_status = status;
}

static int comx_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct comx_channel *ch = dev->priv;
	int rc;

	if (skb->len > dev->mtu + dev->hard_header_len) {
		printk(KERN_ERR "comx_xmit: %s: skb->len %d > dev->mtu %d\n", dev->name,
		(int)skb->len, dev->mtu);
	}
	
	if (ch->debug_flags & DEBUG_COMX_TX) {
		comx_debug_skb(dev, skb, "comx_xmit skb");
	}
	
	rc=ch->LINE_xmit(skb, dev);
//	if (!rc) dev_kfree_skb(skb);

	return rc;
}

static int comx_header(struct sk_buff *skb, struct net_device *dev, 
	unsigned short type, void *daddr, void *saddr, unsigned len) 
{
	struct comx_channel *ch = dev->priv;

	if (ch->LINE_header) {
		return (ch->LINE_header(skb, dev, type, daddr, saddr, len));
	} else {
		return 0;
	}
}

static int comx_rebuild_header(struct sk_buff *skb) 
{
	struct net_device *dev = skb->dev;
	struct comx_channel *ch = dev->priv;

	if (ch->LINE_rebuild_header) {
		return(ch->LINE_rebuild_header(skb));
	} else {
		return 0;
	}
}

int comx_rx(struct net_device *dev, struct sk_buff *skb)
{
	struct comx_channel *ch = dev->priv;

	if (ch->debug_flags & DEBUG_COMX_RX) {
		comx_debug_skb(dev, skb, "comx_rx skb");
	}
	if (skb) {
		netif_rx(skb);
		dev->last_rx = jiffies;
	}
	return 0;
}

static struct net_device_stats *comx_stats(struct net_device *dev)
{
	struct comx_channel *ch = (struct comx_channel *)dev->priv;

	return ch->current_stats;
}

void comx_lineup_func(unsigned long d)
{
	struct net_device *dev = (struct net_device *)d;
	struct comx_channel *ch = dev->priv;

	del_timer(&ch->lineup_timer);
	clear_bit(0, &ch->lineup_pending);

	if (ch->LINE_status) {
		ch->LINE_status(dev, ch->line_status |= LINE_UP);
	}
}

#define LOADAVG(avg, off) (int) \
	((ch->avg_bytes[(ch->loadavg_counter - 1 + ch->loadavg_size * 2) \
	% ch->loadavg_size + off] -  ch->avg_bytes[(ch->loadavg_counter - 1 \
		- ch->loadavg[avg] / ch->loadavg[0] + ch->loadavg_size * 2) \
		% ch->loadavg_size + off]) / ch->loadavg[avg] * 8)

static int comx_statistics(struct net_device *dev, char *page)
{
	struct comx_channel *ch = dev->priv;
	int len = 0;
	int tmp;
	int i = 0;
	char tmpstr[20];
	int tmpstrlen = 0;

	len += sprintf(page + len, "Interface administrative status is %s, "
		"modem status is %s, protocol is %s\n", 
		dev->flags & IFF_UP ? "UP" : "DOWN",
		ch->line_status & LINE_UP ? "UP" : "DOWN",
		ch->line_status & PROTO_LOOP ? "LOOP" : 
		ch->line_status & PROTO_UP ? "UP" : "DOWN");
	len += sprintf(page + len, "Modem status changes: %lu, Transmitter status "
		"is %s, tbusy: %d\n", ch->current_stats->tx_carrier_errors, ch->HW_txe ? 
		ch->HW_txe(dev) ? "IDLE" : "BUSY" : "NOT READY", netif_running(dev));
	len += sprintf(page + len, "Interface load (input): %d / %d / %d bits/s (",
		LOADAVG(0,0), LOADAVG(1, 0), LOADAVG(2, 0));
	tmpstr[0] = 0;
	for (i=0; i != 3; i++) {
		char tf;

		tf = ch->loadavg[i] % 60 == 0 && 
			ch->loadavg[i] / 60 > 0 ? 'm' : 's';
		tmpstrlen += sprintf(tmpstr + tmpstrlen, "%d%c%s", 
			ch->loadavg[i] / (tf == 'm' ? 60 : 1), tf, 
			i == 2 ? ")\n" : "/");
	}
	len += sprintf(page + len, 
		"%s              (output): %d / %d / %d bits/s (%s", tmpstr, 
		LOADAVG(0,ch->loadavg_size), LOADAVG(1, ch->loadavg_size), 
		LOADAVG(2, ch->loadavg_size), tmpstr);

	len += sprintf(page + len, "Debug flags: ");
	tmp = len; i = 0;
	while (comx_debugflags[i].name) {
		if (ch->debug_flags & comx_debugflags[i].value) 
			len += sprintf(page + len, "%s ", 
				comx_debugflags[i].name);
		i++;
	}
	len += sprintf(page + len, "%s\n", tmp == len ? "none" : "");

	len += sprintf(page + len, "RX errors: len: %lu, overrun: %lu, crc: %lu, "
		"aborts: %lu\n           buffer overrun: %lu, pbuffer overrun: %lu\n"
		"TX errors: underrun: %lu\n",
		ch->current_stats->rx_length_errors, ch->current_stats->rx_over_errors, 
		ch->current_stats->rx_crc_errors, ch->current_stats->rx_frame_errors, 
		ch->current_stats->rx_missed_errors, ch->current_stats->rx_fifo_errors,
		ch->current_stats->tx_fifo_errors);

	if (ch->LINE_statistics && (ch->init_status & LINE_OPEN)) {
		len += ch->LINE_statistics(dev, page + len);
	} else {
		len += sprintf(page+len, "Line status: driver not initialized\n");
	}
	if (ch->HW_statistics && (ch->init_status & HW_OPEN)) {
		len += ch->HW_statistics(dev, page + len);
	} else {
		len += sprintf(page+len, "Board status: driver not initialized\n");
	}

	return len;
}

static int comx_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
	struct comx_channel *ch = dev->priv;

	if (ch->LINE_ioctl) {
		return(ch->LINE_ioctl(dev, ifr, cmd));
	}
	return -EINVAL;
}

static void comx_reset_dev(struct net_device *dev)
{
	dev->open = comx_open;
	dev->stop = comx_close;
	dev->hard_start_xmit = comx_xmit;
	dev->hard_header = comx_header;
	dev->rebuild_header = comx_rebuild_header;
	dev->get_stats = comx_stats;
	dev->do_ioctl = comx_ioctl;
	dev->change_mtu = NULL;
	dev->tx_queue_len = 20;
	dev->flags = IFF_NOARP;
}

static int comx_init_dev(struct net_device *dev)
{
	struct comx_channel *ch;

	if ((ch = kmalloc(sizeof(struct comx_channel), GFP_KERNEL)) == NULL) {
		return -ENOMEM;
	}
	memset(ch, 0, sizeof(struct comx_channel));

	ch->loadavg[0] = 5;
	ch->loadavg[1] = 300;
	ch->loadavg[2] = 900;
	ch->loadavg_size = ch->loadavg[2] / ch->loadavg[0] + 1; 
	if ((ch->avg_bytes = kmalloc(ch->loadavg_size * 
		sizeof(unsigned long) * 2, GFP_KERNEL)) == NULL) {
		kfree(ch);
		return -ENOMEM;
	}

	memset(ch->avg_bytes, 0, ch->loadavg_size * sizeof(unsigned long) * 2);
	ch->loadavg_counter = 0;
	ch->loadavg_timer.function = comx_loadavg_timerfun;
	ch->loadavg_timer.data = (unsigned long)dev;
	ch->loadavg_timer.expires = jiffies + HZ * ch->loadavg[0];
	add_timer(&ch->loadavg_timer);

	dev->priv = (void *)ch;
	ch->dev = dev;
	ch->line_status &= ~LINE_UP;

	ch->current_stats = &ch->stats;

	comx_reset_dev(dev);
	return 0;
}

static int comx_read_proc(char *page, char **start, off_t off, int count, 
	int *eof, void *data)
{
	struct proc_dir_entry *file = (struct proc_dir_entry *)data;
	struct net_device *dev = file->parent->data;
	struct comx_channel *ch=(struct comx_channel *)dev->priv;
	int len = 0;

	if (strcmp(file->name, FILENAME_STATUS) == 0) {
		len = comx_statistics(dev, page);
	} else if (strcmp(file->name, FILENAME_HARDWARE) == 0) {
		len = sprintf(page, "%s\n", ch->hardware ? 
			ch->hardware->name : HWNAME_NONE);
	} else if (strcmp(file->name, FILENAME_PROTOCOL) == 0) {
		len = sprintf(page, "%s\n", ch->protocol ? 
			ch->protocol->name : PROTONAME_NONE);
	} else if (strcmp(file->name, FILENAME_LINEUPDELAY) == 0) {
		len = sprintf(page, "%01d\n", ch->lineup_delay);
	}

	if (off >= len) {
		*eof = 1;
		return 0;
	}

	*start = page + off;
	if (count >= len - off) {
		*eof = 1;
	}
	return min_t(int, count, len - off);
}


static int comx_root_read_proc(char *page, char **start, off_t off, int count, 
	int *eof, void *data)
{
	struct proc_dir_entry *file = (struct proc_dir_entry *)data;
	struct comx_hardware *hw;