patch-2.1.25 linux/drivers/net/sdla_ppp.c

• Lines: 1026
• Date: Sun Feb 2 16:43:08 1997
• Orig file: v2.1.24/linux/drivers/net/sdla_ppp.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v2.1.24/linux/drivers/net/sdla_ppp.c linux/drivers/net/sdla_ppp.c
@@ -0,0 +1,1025 @@
+/*****************************************************************************
+* sdla_ppp.c	WANPIPE(tm) Multiprotocol WAN Link Driver. PPP module.
+*
+* Author:	Gene Kozin	<genek@compuserve.com>
+*
+* Copyright:	(c) 1995-1997 Sangoma Technologies Inc.
+*
+*		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.
+* ============================================================================
+* Jan 06, 1997	Gene Kozin	Initial version.
+*****************************************************************************/
+
+#if	!defined(__KERNEL__) || !defined(MODULE)
+#error	This code MUST be compiled as a kernel module!
+#endif
+
+#include <linux/kernel.h>	/* printk(), and other useful stuff */
+#include <linux/stddef.h>	/* offsetof(), etc. */
+#include <linux/errno.h>	/* return codes */
+#include <linux/string.h>	/* inline memset(), etc. */
+#include <linux/malloc.h>	/* kmalloc(), kfree() */
+#include <linux/router.h>	/* WAN router definitions */
+#include <linux/wanpipe.h>	/* WANPIPE common user API definitions */
+#include <linux/if_arp.h>	/* ARPHRD_* defines */
+#include <asm/byteorder.h>	/* htons(), etc. */
+
+#define	_GNUC_
+#include <linux/sdla_ppp.h>		/* PPP firmware API definitions */
+
+/****** Defines & Macros ****************************************************/
+
+#ifdef	_DEBUG_
+#define	STATIC
+#else
+#define	STATIC		static
+#endif
+
+#define	CMD_OK		0		/* normal firmware return code */
+#define	CMD_TIMEOUT	0xFF		/* firmware command timed out */
+
+#define	PPP_DFLT_MTU	1500		/* default MTU */
+#define	PPP_MAX_MTU	4000		/* maximum MTU */
+#define PPP_HDR_LEN	1
+
+#define	CONNECT_TIMEOUT	(90*HZ)		/* link connection timeout */
+#define	HOLD_DOWN_TIME	(30*HZ)		/* link hold down time */
+
+/****** Function Prototypes *************************************************/
+
+/* WAN link driver entry points. These are called by the WAN router module. */
+static int update (wan_device_t* wandev);
+static int new_if (wan_device_t* wandev, struct device* dev,
+	wanif_conf_t* conf);
+static int del_if (wan_device_t* wandev, struct device* dev);
+
+/* Network device interface */
+static int if_init   (struct device* dev);
+static int if_open   (struct device* dev);
+static int if_close  (struct device* dev);
+static int if_header (struct sk_buff* skb, struct device* dev,
+	unsigned short type, void* daddr, void* saddr, unsigned len);
+static int if_rebuild_hdr (void* hdr, struct device* dev, unsigned long raddr,
+	struct sk_buff* skb);
+static int if_send (struct sk_buff* skb, struct device* dev);
+static struct enet_statistics* if_stats (struct device* dev);
+
+/* PPP firmware interface functions */
+static int ppp_read_version (sdla_t* card, char* str);
+static int ppp_configure (sdla_t* card, void* data);
+static int ppp_set_intr_mode (sdla_t* card, unsigned mode);
+static int ppp_comm_enable (sdla_t* card);
+static int ppp_comm_disable (sdla_t* card);
+static int ppp_send (sdla_t* card, void* data, unsigned len, unsigned proto);
+static int ppp_error (sdla_t *card, int err, ppp_mbox_t* mb);
+
+/* Interrupt handlers */
+STATIC void wpp_isr (sdla_t* card);
+static void rx_intr (sdla_t* card);
+static void tx_intr (sdla_t* card);
+
+/* Background polling routines */
+static void wpp_poll (sdla_t* card);
+static void poll_active (sdla_t* card);
+static void poll_connecting (sdla_t* card);
+static void poll_disconnected (sdla_t* card);
+
+/* Miscellaneous functions */
+static int config502 (sdla_t* card);
+static int config508 (sdla_t* card);
+static void show_disc_cause (sdla_t* card, unsigned cause);
+static unsigned char bps_to_speed_code (unsigned long bps);
+
+/****** Public Functions ****************************************************/
+
+/*============================================================================
+ * PPP protocol initialization routine.
+ *
+ * This routine is called by the main WANPIPE module during setup.  At this
+ * point adapter is completely initialized and firmware is running.
+ *  o read firmware version (to make sure it's alive)
+ *  o configure adapter
+ *  o initialize protocol-specific fields of the adapter data space.
+ *
+ * Return:	0	o.k.
+ *		< 0	failure.
+ */
+int wpp_init (sdla_t* card, wandev_conf_t* conf)
+{
+	union
+	{
+		char str[80];
+	} u;
+
+	/* Verify configuration ID */
+	if (conf->config_id != WANCONFIG_PPP)
+	{
+		printk(KERN_INFO "%s: invalid configuration ID %u!\n",
+			card->devname, conf->config_id)
+		;
+		return -EINVAL;
+	}
+
+	/* Initialize protocol-specific fields */
+	switch (card->hw.fwid)
+	{
+	case SFID_PPP502:
+		card->mbox  = (void*)(card->hw.dpmbase + PPP502_MB_OFFS);
+		card->flags = (void*)(card->hw.dpmbase + PPP502_FLG_OFFS);
+		break;
+
+	case SFID_PPP508:
+		card->mbox  = (void*)(card->hw.dpmbase + PPP508_MB_OFFS);
+		card->flags = (void*)(card->hw.dpmbase + PPP508_FLG_OFFS);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	/* Read firmware version.  Note that when adapter initializes, it
+	 * clears the mailbox, so it may appear that the first command was
+	 * executed successfully when in fact it was merely erased. To work
+	 * around this, we execute the first command twice.
+	 */
+	if (ppp_read_version(card, NULL) || ppp_read_version(card, u.str))
+		return -EIO
+	;
+	printk(KERN_INFO "%s: running PPP firmware v%s\n",
+		card->devname, u.str)
+	;
+
+	/* Adjust configuration and set defaults */
+	card->wandev.mtu = (conf->mtu) ?
+		min(conf->mtu, PPP_MAX_MTU) : PPP_DFLT_MTU
+	;
+	card->wandev.bps	= conf->bps;
+	card->wandev.interface	= conf->interface;
+	card->wandev.clocking	= conf->clocking;
+	card->wandev.station	= conf->station;
+	card->isr		= &wpp_isr;
+	card->poll		= &wpp_poll;
+	card->wandev.update	= &update;
+	card->wandev.new_if	= &new_if;
+	card->wandev.del_if	= &del_if;
+	card->wandev.state	= WAN_DISCONNECTED;
+	return 0;
+}
+
+/******* WAN Device Driver Entry Points *************************************/
+
+/*============================================================================
+ * Update device status & statistics.
+ */
+static int update (wan_device_t* wandev)
+{
+/*
+	sdla_t* card = wandev->private;
+*/
+	return 0;
+}
+
+/*============================================================================
+ * Create new logical channel.
+ * This routine is called by the router when ROUTER_IFNEW IOCTL is being
+ * handled.
+ * o parse media- and hardware-specific configuration
+ * o make sure that a new channel can be created
+ * o allocate resources, if necessary
+ * o prepare network device structure for registaration.
+ *
+ * Return:	0	o.k.
+ *		< 0	failure (channel will not be created)
+ */
+static int new_if (wan_device_t* wandev, struct device* dev, wanif_conf_t* conf)
+{
+	sdla_t* card = wandev->private;
+
+	if (wandev->ndev)
+		return -EEXIST
+	;
+	if ((conf->name[0] == '\0') || (strlen(conf->name) > WAN_IFNAME_SZ))
+	{
+		printk(KERN_INFO "%s: invalid interface name!\n",
+			card->devname)
+		;
+		return -EINVAL;
+	}
+
+	/* initialize data */
+	strcpy(card->u.p.if_name, conf->name);
+
+	/* prepare network device data space for registration */
+	dev->name = card->u.p.if_name;
+	dev->init = &if_init;
+	dev->priv = card;
+	return 0;
+}
+
+/*============================================================================
+ * Delete logical channel.
+ */
+static int del_if (wan_device_t* wandev, struct device* dev)
+{
+	return 0;
+}
+
+/****** Network Device Interface ********************************************/
+
+/*============================================================================
+ * Initialize Linux network interface.
+ *
+ * This routine is called only once for each interface, during Linux network
+ * interface registration.  Returning anything but zero will fail interface
+ * registration.
+ */
+static int if_init (struct device* dev)
+{
+	sdla_t* card = dev->priv;
+	wan_device_t* wandev = &card->wandev;
+	int i;
+
+	/* Initialize device driver entry points */
+	dev->open		= &if_open;
+	dev->stop		= &if_close;
+	dev->hard_header	= &if_header;
+	dev->rebuild_header	= &if_rebuild_hdr;
+	dev->hard_start_xmit	= &if_send;
+	dev->get_stats		= &if_stats;
+
+	/* Initialize media-specific parameters */
+	dev->family		= AF_INET;	/* address family */
+	dev->type		= ARPHRD_PPP;	/* ARP h/w type */
+	dev->mtu		= wandev->mtu;
+	dev->hard_header_len	= PPP_HDR_LEN;	/* media header length */
+
+	/* Initialize hardware parameters (just for reference) */
+	dev->irq		= wandev->irq;
+	dev->dma		= wandev->dma;
+	dev->base_addr		= wandev->ioport;
+	dev->mem_start		= wandev->maddr;
+	dev->mem_end		= wandev->maddr + wandev->msize - 1;
+
+	/* Initialize socket buffers */
+	for (i = 0; i < DEV_NUMBUFFS; ++i)
+		skb_queue_head_init(&dev->buffs[i])
+	;
+	return 0;
+}
+
+/*============================================================================
+ * Open network interface.
+ * o enable communications and interrupts.
+ * o prevent module from unloading by incrementing use count
+ *
+ * Return 0 if O.k. or errno.
+ */
+static int if_open (struct device* dev)
+{
+	sdla_t* card = dev->priv;
+	int err = 0;
+
+	if (dev->start)
+		return -EBUSY		/* only one open is allowed */
+	;
+	if (set_bit(0, (void*)&card->wandev.critical))
+		return -EAGAIN;
+	;
+	if ((card->hw.fwid == SFID_PPP502) ? config502(card) : config508(card))
+	{
+		err = -EIO;
+		goto split;
+	}
+
+	/* Initialize Rx/Tx buffer control fields */
+	if (card->hw.fwid == SFID_PPP502)
+	{
+		ppp502_buf_info_t* info =
+			(void*)(card->hw.dpmbase + PPP502_BUF_OFFS)
+		;
+
+		card->u.p.txbuf_base = (void*)(card->hw.dpmbase +
+			info->txb_offs)
+		;
+		card->u.p.txbuf_last = (ppp_buf_ctl_t*)card->u.p.txbuf_base +
+			(info->txb_num - 1)
+		;
+		card->u.p.rxbuf_base = (void*)(card->hw.dpmbase +
+			info->rxb_offs)
+		;
+		card->u.p.rxbuf_last = (ppp_buf_ctl_t*)card->u.p.rxbuf_base +
+			(info->rxb_num - 1)
+		;
+	}
+	else
+	{
+		ppp508_buf_info_t* info =
+			(void*)(card->hw.dpmbase + PPP508_BUF_OFFS)
+		;
+
+		card->u.p.txbuf_base = (void*)(card->hw.dpmbase +
+			(info->txb_ptr - PPP508_MB_VECT))
+		;
+		card->u.p.txbuf_last = (ppp_buf_ctl_t*)card->u.p.txbuf_base +
+			(info->txb_num - 1)
+		;
+		card->u.p.rxbuf_base = (void*)(card->hw.dpmbase +
+			(info->rxb_ptr - PPP508_MB_VECT))
+		;
+		card->u.p.rxbuf_last = (ppp_buf_ctl_t*)card->u.p.rxbuf_base +
+			(info->rxb_num - 1)
+		;
+		card->u.p.rx_base = info->rxb_base;
+		card->u.p.rx_top  = info->rxb_end;
+	}
+	card->u.p.txbuf = card->u.p.txbuf_base;
+	card->rxmb = card->u.p.rxbuf_base;
+
+	if (ppp_set_intr_mode(card, 0x03) || ppp_comm_enable(card))
+	{
+		err = -EIO;
+		goto split;
+	}
+	wanpipe_set_state(card, WAN_CONNECTING);
+	wanpipe_open(card);
+	dev->mtu = min(dev->mtu, card->wandev.mtu);
+	dev->interrupt = 0;
+	dev->tbusy = 0;
+	dev->start = 1;
+
+split:
+	card->wandev.critical = 0;
+	return err;
+}
+
+/*============================================================================
+ * Close network interface.
+ * o if this is the last open, then disable communications and interrupts.
+ * o reset flags.
+ */
+static int if_close (struct device* dev)
+{
+	sdla_t* card = dev->priv;
+
+	if (set_bit(0, (void*)&card->wandev.critical))
+		return -EAGAIN;
+	;
+	dev->start = 0;
+	wanpipe_close(card);
+	wanpipe_set_state(card, WAN_DISCONNECTED);
+	ppp_set_intr_mode(card, 0);
+	ppp_comm_disable(card);
+	card->wandev.critical = 0;
+	return 0;
+}
+
+/*============================================================================
+ * Build media header.
+ *
+ * The trick here is to put packet type (Ethertype) into 'protocol' field of
+ * the socket buffer, so that we don't forget it.  If packet type is not
+ * supported, set skb->protocol to 0 and discard packet later.
+ *
+ * Return:	media header length.
+ */
+static int if_header (struct sk_buff* skb, struct device* dev,
+	unsigned short type, void* daddr, void* saddr, unsigned len)
+{
+	switch (type)
+	{
+	case ETH_P_IP:
+	case ETH_P_IPX:
+		skb->protocol = type;
+		break;
+
+	default:
+		skb->protocol = 0;
+	}
+	return PPP_HDR_LEN;
+}
+
+/*============================================================================
+ * Re-build media header.
+ *
+ * Return:	1	physical address resolved.
+ *		0	physical address not resolved
+ */
+static int if_rebuild_hdr (void* hdr, struct device* dev, unsigned long raddr,
+			   struct sk_buff* skb)
+{
+	sdla_t* card = dev->priv;
+
+	printk(KERN_INFO "%s: rebuild_header() called for interface %s!\n",
+		card->devname, dev->name)
+	;
+	return 1;
+}
+
+/*============================================================================
+ * Send a packet on a network interface.
+ * o set tbusy flag (marks start of the transmission) to block a timer-based
+ *   transmit from overlapping.
+ * o check link state. If link is not up, then drop the packet.
+ * o execute adapter send command.
+ * o free socket buffer
+ *
+ * Return:	0	complete (socket buffer must be freed)
+ *		non-0	packet may be re-transmitted (tbusy must be set)
+ *
+ * Notes:
+ * 1. This routine is called either by the protocol stack or by the "net
+ *    bottom half" (with interrupts enabled).
+ * 2. Setting tbusy flag will inhibit further transmit requests from the
+ *    protocol stack and can be used for flow control with protocol layer.
+ */
+static int if_send (struct sk_buff* skb, struct device* dev)
+{
+	sdla_t* card = dev->priv;
+	int retry = 0;
+
+	if (skb == NULL)
+	{
+		/* If we get here, some higher layer thinks we've missed an
+		 * tx-done interrupt.
+		 */
+#ifdef _DEBUG_
+		printk(KERN_INFO "%s: interface %s got kicked!\n",
+			card->devname, dev->name)
+		;
+#endif
+		dev_tint(dev);
+		return 0;
+	}
+
+	if (set_bit(0, (void*)&card->wandev.critical))
+	{
+#ifdef _DEBUG_
+		printk(KERN_INFO "%s: if_send() hit critical section!\n",
+			card->devname)
+		;
+#endif
+		return 1;
+	}
+
+	if (set_bit(0, (void*)&dev->tbusy))
+	{
+#ifdef _DEBUG_
+		printk(KERN_INFO "%s: Tx collision on interface %s!\n",
+			card->devname, dev->name)
+		;
+#endif
+		++card->wandev.stats.collisions;
+		retry = 1;
+	}
+	else if (card->wandev.state != WAN_CONNECTED)
+		++card->wandev.stats.tx_dropped
+	;
+	else if (!skb->protocol)
+		++card->wandev.stats.tx_errors
+	;
+	else if (ppp_send(card, skb->data, skb->len, skb->protocol))
+	{
+		ppp_flags_t* flags = card->flags;
+
+		flags->imask |= 0x02;	/* unmask Tx interrupts */
+		retry = 1;
+	}
+	else ++card->wandev.stats.tx_packets;
+
+	if (!retry)
+	{
+		dev_kfree_skb(skb, FREE_WRITE);
+		dev->tbusy = 0;
+	}
+	card->wandev.critical = 0;
+	return retry;
+}
+
+/*============================================================================
+ * Get ethernet-style interface statistics.
+ * Return a pointer to struct enet_statistics.
+ */
+static struct enet_statistics* if_stats (struct device* dev)
+{
+	sdla_t* card = dev->priv;
+
+	return &card->wandev.stats;
+}
+
+/****** PPP Firmware Interface Functions ************************************/
+
+/*============================================================================
+ * Read firmware code version.
+ *	Put code version as ASCII string in str. 
+ */
+static int ppp_read_version (sdla_t* card, char* str)
+{
+	ppp_mbox_t* mb = card->mbox;
+	int err;
+
+	memset(&mb->cmd, 0, sizeof(ppp_cmd_t));
+	mb->cmd.command = PPP_READ_CODE_VERSION;
+	err = sdla_exec(mb) ? mb->cmd.result : CMD_TIMEOUT;
+	if (err != CMD_OK) ppp_error(card, err, mb);
+	else if (str)
+	{
+		int len = mb->cmd.length;
+
+		memcpy(str, mb->data, len);
+		str[len] = '\0';
+	}
+	return err;
+}
+
+/*============================================================================
+ * Configure PPP firmware.
+ */
+static int ppp_configure (sdla_t* card, void* data)
+{
+	ppp_mbox_t* mb = card->mbox;
+	int data_len = (card->hw.fwid == SFID_PPP502) ?
+		sizeof(ppp502_conf_t) : sizeof(ppp508_conf_t)
+	;
+	int err;
+
+	memset(&mb->cmd, 0, sizeof(ppp_cmd_t));
+	memcpy(mb->data, data, data_len);
+	mb->cmd.length  = data_len;
+	mb->cmd.command = PPP_SET_CONFIG;
+	err = sdla_exec(mb) ? mb->cmd.result : CMD_TIMEOUT;
+	if (err != CMD_OK) ppp_error(card, err, mb);
+	return err;
+}
+
+/*============================================================================
+ * Set interrupt mode.
+ */
+static int ppp_set_intr_mode (sdla_t* card, unsigned mode)
+{
+	ppp_mbox_t* mb = card->mbox;
+	int err;
+
+	memset(&mb->cmd, 0, sizeof(ppp_cmd_t));
+	mb->data[0] = mode;
+	switch (card->hw.fwid)
+	{
+	case SFID_PPP502:
+		mb->cmd.length  = 1;
+		break;
+
+	case SFID_PPP508:
+	default:
+		mb->data[1] = card->hw.irq;
+		mb->cmd.length = 2;
+	}
+	mb->cmd.command = PPP_SET_INTR_FLAGS;
+	err = sdla_exec(mb) ? mb->cmd.result : CMD_TIMEOUT;
+	if (err != CMD_OK) ppp_error(card, err, mb);
+	return err;
+}
+
+/*============================================================================
+ * Enable communications.
+ */
+static int ppp_comm_enable (sdla_t* card)
+{
+	ppp_mbox_t* mb = card->mbox;
+	int err;
+
+	memset(&mb->cmd, 0, sizeof(ppp_cmd_t));
+	mb->cmd.command = PPP_COMM_ENABLE;
+	err = sdla_exec(mb) ? mb->cmd.result : CMD_TIMEOUT;
+	if (err != CMD_OK) ppp_error(card, err, mb);
+	return err;
+}
+
+/*============================================================================
+ * Disable communications.
+ */
+static int ppp_comm_disable (sdla_t* card)
+{
+	ppp_mbox_t* mb = card->mbox;
+	int err;
+
+	memset(&mb->cmd, 0, sizeof(ppp_cmd_t));
+	mb->cmd.command = PPP_COMM_DISABLE;
+	err = sdla_exec(mb) ? mb->cmd.result : CMD_TIMEOUT;
+	if (err != CMD_OK) ppp_error(card, err, mb);
+	return err;
+}
+
+/*============================================================================
+ * Send packet.
+ *	Return:	0 - o.k.
+ *		1 - no transmit buffers available
+ */
+static int ppp_send (sdla_t* card, void* data, unsigned len, unsigned proto)
+{
+	ppp_buf_ctl_t* txbuf = card->u.p.txbuf;
+	unsigned long addr, cpu_flags;
+
+	if (txbuf->flag)
+		return 1
+	;
+	if (card->hw.fwid == SFID_PPP502)
+		addr = (txbuf->buf.o_p[1] << 8) + txbuf->buf.o_p[0]
+	; 
+	else addr = txbuf->buf.ptr;
+
+	save_flags(cpu_flags);
+	cli();
+	sdla_poke(&card->hw, addr, data, len);
+	restore_flags(cpu_flags);
+	txbuf->length = len;		/* frame length */
+	if (proto == ETH_P_IPX)
+		txbuf->proto = 0x01	/* protocol ID */
+	;
+	txbuf->flag = 1;		/* start transmission */
+
+	/* Update transmit buffer control fields */
+	card->u.p.txbuf = ++txbuf;
+	if ((void*)txbuf > card->u.p.txbuf_last)
+		card->u.p.txbuf = card->u.p.txbuf_base
+	;
+	return 0;
+}
+
+/****** Firmware Error Handler **********************************************/
+
+/*============================================================================
+ * Firmware error handler.
+ *	This routine is called whenever firmware command returns non-zero
+ *	return code.
+ *
+ * Return zero if previous command has to be cancelled.
+ */
+static int ppp_error (sdla_t *card, int err, ppp_mbox_t* mb)
+{
+	unsigned cmd = mb->cmd.command;
+
+	switch (err)
+	{
+	case CMD_TIMEOUT:
+		printk(KERN_ERR "%s: command 0x%02X timed out!\n",
+			card->devname, cmd)
+		;
+		break;
+
+	default:
+		printk(KERN_INFO "%s: command 0x%02X returned 0x%02X!\n",
+			card->devname, cmd, err)
+		;
+	}
+	return 0;
+}
+
+/****** Interrupt Handlers **************************************************/
+
+/*============================================================================
+ * PPP interrupt service routine.
+ */
+STATIC void wpp_isr (sdla_t* card)
+{
+	ppp_flags_t* flags = card->flags;
+
+	switch (flags->iflag)
+	{
+	case 0x01:	/* receive interrupt */
+		rx_intr(card);
+		break;
+
+	case 0x02:	/* transmit interrupt */
+		flags->imask &= ~0x02;
+		tx_intr(card);
+		break;
+
+	default:	/* unexpected interrupt */
+		printk(KERN_INFO "%s: spurious interrupt 0x%02X!\n",
+			card->devname, flags->iflag)
+		;
+	}
+	flags->iflag = 0;
+}
+
+/*============================================================================
+ * Receive interrupt handler.
+ */
+static void rx_intr (sdla_t* card)
+{
+	ppp_buf_ctl_t* rxbuf = card->rxmb;
+	struct device* dev = card->wandev.dev;
+	struct sk_buff* skb;
+	unsigned len;
+	void* buf;
+
+	if (rxbuf->flag != 0x01)
+	{
+		printk(KERN_INFO "%s: corrupted Rx buffer @ 0x%X!\n",
+			card->devname, (unsigned)rxbuf)
+		;
+		return;
+	}
+
+	if (!dev || !dev->start)
+		goto rx_done
+	;
+	len  = rxbuf->length;
+
+	/* Allocate socket buffer */
+	skb = dev_alloc_skb(len);
+	if (skb == NULL)
+	{
+		printk(KERN_INFO "%s: no socket buffers available!\n",
+			card->devname)
+		;
+		++card->wandev.stats.rx_dropped;
+		goto rx_done;
+	}
+
+	/* Copy data to the socket buffer */
+	if (card->hw.fwid == SFID_PPP502)
+	{
+		unsigned addr = (rxbuf->buf.o_p[1] << 8) + rxbuf->buf.o_p[0]; 
+
+		buf = skb_put(skb, len);
+		sdla_peek(&card->hw, addr, buf, len);
+	}
+	else
+	{
+		unsigned addr = rxbuf->buf.ptr;
+
+		if ((addr + len) > card->u.p.rx_top)
+		{
+			unsigned tmp = card->u.p.rx_top - addr;
+
+			buf = skb_put(skb, tmp);
+			sdla_peek(&card->hw, addr, buf, tmp);
+			addr = card->u.p.rx_base;
+			len -= tmp;
+		}
+		buf = skb_put(skb, len);
+		sdla_peek(&card->hw, addr, buf, len);
+	}
+
+	/* Decapsulate packet and pass it up the protocol stack */
+	switch (rxbuf->proto)
+	{
+	case 0x00:
+		skb->protocol = htons(ETH_P_IP);
+		break;
+
+	case 0x01:
+		skb->protocol = htons(ETH_P_IPX);
+		break;
+	}
+	skb->dev = dev;
+	netif_rx(skb);
+	++card->wandev.stats.rx_packets;
+
+rx_done:
+	/* Release buffer element and calculate a pointer to the next one */
+	rxbuf->flag = (card->hw.fwid == SFID_PPP502) ? 0xFF : 0x00;
+	card->rxmb = ++rxbuf;
+	if ((void*)rxbuf > card->u.p.rxbuf_last)
+		card->rxmb = card->u.p.rxbuf_base
+	;
+}
+
+/*============================================================================
+ * Transmit interrupt handler.
+ */
+static void tx_intr (sdla_t* card)
+{
+	struct device* dev = card->wandev.dev;
+
+	if (!dev || !dev->start)
+		return
+	;
+	dev->tbusy = 0;
+	dev_tint(dev);
+}
+
+/****** Background Polling Routines  ****************************************/
+
+/*============================================================================
+ * Main polling routine.
+ * This routine is repeatedly called by the WANPIPE 'thread' to allow for
+ * time-dependent housekeeping work.
+ *
+ * Notes:
+ * 1. This routine may be called on interrupt context with all interrupts
+ *    enabled. Beware!
+ */
+static void wpp_poll (sdla_t* card)
+{
+	switch(card->wandev.state)
+	{
+	case WAN_CONNECTED:
+		poll_active(card);
+		break;
+
+	case WAN_CONNECTING:
+		poll_connecting(card);
+		break;
+
+	case WAN_DISCONNECTED:
+		poll_disconnected(card);
+		break;
+	}
+}
+
+/*============================================================================
+ * Monitor active link phase.
+ */
+static void poll_active (sdla_t* card)
+{
+	ppp_flags_t* flags = card->flags;
+
+	if (flags->disc_cause & 0x03)
+	{
+		wanpipe_set_state(card, WAN_DISCONNECTED);
+		show_disc_cause(card, flags->disc_cause);
+	}
+}
+
+/*============================================================================
+ * Monitor link establishment phase.
+ * o if connection timed out, disconnect the link.
+ */
+static void poll_connecting (sdla_t* card)
+{
+	ppp_flags_t* flags = card->flags;
+
+	if (flags->lcp_state == 0x09)
+	{
+		wanpipe_set_state(card, WAN_CONNECTED);
+	}
+	else if (flags->disc_cause & 0x03)
+	{
+		wanpipe_set_state(card, WAN_DISCONNECTED);
+		show_disc_cause(card, flags->disc_cause);
+	}
+}
+
+/*============================================================================
+ * Monitor physical link disconnected phase.
+ *  o if interface is up and the hold-down timeout has expired, then retry
+ *    connection.
+ */
+static void poll_disconnected (sdla_t* card)
+{
+	struct device* dev = card->wandev.dev;
+
+	if (dev && dev->start &&
+	    ((jiffies - card->state_tick) > HOLD_DOWN_TIME))
+	{
+		wanpipe_set_state(card, WAN_CONNECTING);
+		ppp_comm_enable(card);
+	}
+}
+
+/****** Miscellaneous Functions *********************************************/
+
+/*============================================================================
+ * Configure S502 adapter.
+ */
+static int config502 (sdla_t* card)
+{
+	ppp502_conf_t cfg;
+
+	/* Prepare PPP configuration structure */
+	memset(&cfg, 0, sizeof(ppp502_conf_t));
+
+	if (card->wandev.clocking)
+		cfg.line_speed = bps_to_speed_code(card->wandev.bps)
+	;
+	cfg.txbuf_num		= 4;
+	cfg.mtu_local		= card->wandev.mtu;
+	cfg.mtu_remote		= card->wandev.mtu;
+	cfg.restart_tmr		= 30;
+	cfg.auth_rsrt_tmr	= 30;
+	cfg.auth_wait_tmr	= 300;
+	cfg.mdm_fail_tmr	= 5;
+	cfg.dtr_drop_tmr	= 1;
+	cfg.connect_tmout	= 900;
+	cfg.conf_retry		= 10;
+	cfg.term_retry		= 2;
+	cfg.fail_retry		= 5;
+	cfg.auth_retry		= 10;
+	cfg.ip_options		= 0x80;
+	cfg.ipx_options		= 0xA0;
+/*
+	cfg.ip_local		= dev->pa_addr;
+	cfg.ip_remote		= dev->pa_dstaddr;
+*/
+	return ppp_configure(card, &cfg);
+}
+
+/*============================================================================
+ * Configure S508 adapter.
+ */
+static int config508 (sdla_t* card)
+{
+	ppp508_conf_t cfg;
+
+	/* Prepare PPP configuration structure */
+	memset(&cfg, 0, sizeof(ppp508_conf_t));
+
+	if (card->wandev.clocking)
+		cfg.line_speed = card->wandev.bps
+	;
+	if (card->wandev.interface == WANOPT_RS232)
+		cfg.conf_flags |= 0x0020;
+	;
+	cfg.txbuf_percent	= 60;	/* % of Tx bufs */
+	cfg.mtu_local		= card->wandev.mtu;
+	cfg.mtu_remote		= card->wandev.mtu;
+	cfg.restart_tmr		= 30;
+	cfg.auth_rsrt_tmr	= 30;
+	cfg.auth_wait_tmr	= 300;
+	cfg.mdm_fail_tmr	= 5;
+	cfg.dtr_drop_tmr	= 1;
+	cfg.connect_tmout	= 900;
+	cfg.conf_retry		= 10;
+	cfg.term_retry		= 2;
+	cfg.fail_retry		= 5;
+	cfg.auth_retry		= 10;
+	cfg.ip_options		= 0x80;
+	cfg.ipx_options		= 0xA0;
+/*
+	cfg.ip_local		= dev->pa_addr;
+	cfg.ip_remote		= dev->pa_dstaddr;
+*/
+	return ppp_configure(card, &cfg);
+}
+
+/*============================================================================
+ * Show disconnection cause.
+ */
+static void show_disc_cause (sdla_t* card, unsigned cause)
+{
+	if (cause & 0x0002) printk(KERN_INFO
+		"%s: link terminated by peer\n", card->devname)
+	;
+	else if (cause & 0x0004) printk(KERN_INFO
+		"%s: link terminated by user\n", card->devname)
+	;
+	else if (cause & 0x0008) printk(KERN_INFO
+		"%s: authentication failed\n", card->devname)
+	;
+	else if (cause & 0x0010) printk(KERN_INFO
+		"%s: authentication protocol negotiation failed\n",
+		card->devname)
+	;
+	else if (cause & 0x0020) printk(KERN_INFO
+		"%s: peer's request for authentication rejected\n",
+		card->devname)
+	;
+	else if (cause & 0x0040) printk(KERN_INFO
+		"%s: MRU option rejected by peer\n", card->devname)
+	;
+	else if (cause & 0x0080) printk(KERN_INFO
+		"%s: peer's MRU was too small\n", card->devname)
+	;
+	else if (cause & 0x0100) printk(KERN_INFO
+		"%s: failed to negotiate peer's LCP options\n",
+		card->devname)
+	;
+	else if (cause & 0x0200) printk(KERN_INFO
+		"%s: failed to negotiate peer's IPCP options\n",
+		card->devname)
+	;
+	else if (cause & 0x0400) printk(KERN_INFO
+		"%s: failed to negotiate peer's IPXCP options\n",
+		card->devname)
+	;
+}
+
+/*============================================================================
+ * Convert line speed in bps to a number used by S502 code.
+ */
+static unsigned char bps_to_speed_code (unsigned long bps)
+{
+	unsigned char	number;
+
+	if (bps <= 1200)        number = 0x01 ;
+	else if (bps <= 2400)   number = 0x02;
+	else if (bps <= 4800)   number = 0x03;
+	else if (bps <= 9600)   number = 0x04;
+	else if (bps <= 19200)  number = 0x05;
+	else if (bps <= 38400)  number = 0x06;
+	else if (bps <= 45000)  number = 0x07;
+	else if (bps <= 56000)  number = 0x08;
+	else if (bps <= 64000)  number = 0x09;
+	else if (bps <= 74000)  number = 0x0A;
+	else if (bps <= 112000) number = 0x0B;
+	else if (bps <= 128000) number = 0x0C;
+	else number = 0x0D;
+
+	return number;
+}
+
+/****** End *****************************************************************/