drivers/net/ixp2000/ixpdev.c - kernel/msm - Gitiles

 /*
  * IXP2000 MSF network device driver
  * Copyright (C) 2004, 2005 Lennert Buytenhek <buytenh@wantstofly.org>
  * Dedicated to Marija Kulikova.
  *
  * 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.
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/init.h>
 #include <linux/moduleparam.h>
 #include <asm/hardware/uengine.h>
 #include <asm/mach-types.h>
 #include <asm/io.h>
 #include "ixp2400_rx.ucode"
 #include "ixp2400_tx.ucode"
 #include "ixpdev_priv.h"
 #include "ixpdev.h"

 #define DRV_MODULE_VERSION	"0.2"

 static int nds_count;
 static struct net_device **nds;
 static int nds_open;
 static void (*set_port_admin_status)(int port, int up);

 static struct ixpdev_rx_desc * const rx_desc =
 	(struct ixpdev_rx_desc *)(IXP2000_SRAM0_VIRT_BASE + RX_BUF_DESC_BASE);
 static struct ixpdev_tx_desc * const tx_desc =
 	(struct ixpdev_tx_desc *)(IXP2000_SRAM0_VIRT_BASE + TX_BUF_DESC_BASE);
 static int tx_pointer;


 static int ixpdev_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct ixpdev_priv *ip = netdev_priv(dev);
 	struct ixpdev_tx_desc *desc;
 	int entry;

 	if (unlikely(skb->len > PAGE_SIZE)) {
 		/* @@@ Count drops.  */
 		dev_kfree_skb(skb);
 		return 0;
 	}

 	entry = tx_pointer;
 	tx_pointer = (tx_pointer + 1) % TX_BUF_COUNT;

 	desc = tx_desc + entry;
 	desc->pkt_length = skb->len;
 	desc->channel = ip->channel;

 	skb_copy_and_csum_dev(skb, phys_to_virt(desc->buf_addr));
 	dev_kfree_skb(skb);

 	ixp2000_reg_write(RING_TX_PENDING,
 		TX_BUF_DESC_BASE + (entry * sizeof(struct ixpdev_tx_desc)));

 	dev->trans_start = jiffies;

 	local_irq_disable();
 	ip->tx_queue_entries++;
 	if (ip->tx_queue_entries == TX_BUF_COUNT_PER_CHAN)
 		netif_stop_queue(dev);
 	local_irq_enable();

 	return 0;
 }


 static int ixpdev_rx(struct net_device *dev, int *budget)
 {
 	while (*budget > 0) {
 		struct ixpdev_rx_desc *desc;
 		struct sk_buff *skb;
 		void *buf;
 		u32 _desc;

 		_desc = ixp2000_reg_read(RING_RX_DONE);
 		if (_desc == 0)
 			return 0;

 		desc = rx_desc +
 			((_desc - RX_BUF_DESC_BASE) / sizeof(struct ixpdev_rx_desc));
 		buf = phys_to_virt(desc->buf_addr);

 		if (desc->pkt_length < 4 || desc->pkt_length > PAGE_SIZE) {
 			printk(KERN_ERR "ixp2000: rx err, length %d\n",
 					desc->pkt_length);
 			goto err;
 		}

 		if (desc->channel < 0 || desc->channel >= nds_count) {
 			printk(KERN_ERR "ixp2000: rx err, channel %d\n",
 					desc->channel);
 			goto err;
 		}

 		/* @@@ Make FCS stripping configurable.  */
 		desc->pkt_length -= 4;

 		if (unlikely(!netif_running(nds[desc->channel])))
 			goto err;

 		skb = dev_alloc_skb(desc->pkt_length + 2);
 		if (likely(skb != NULL)) {
 			skb->dev = nds[desc->channel];
 			skb_reserve(skb, 2);
 			eth_copy_and_sum(skb, buf, desc->pkt_length, 0);
 			skb_put(skb, desc->pkt_length);
 			skb->protocol = eth_type_trans(skb, skb->dev);

 			skb->dev->last_rx = jiffies;

 			netif_receive_skb(skb);
 		}

 err:
 		ixp2000_reg_write(RING_RX_PENDING, _desc);
 		dev->quota--;
 		(*budget)--;
 	}

 	return 1;
 }

 /* dev always points to nds[0].  */
 static int ixpdev_poll(struct net_device *dev, int *budget)
 {
 	/* @@@ Have to stop polling when nds[0] is administratively
 	 * downed while we are polling.  */
 	do {
 		ixp2000_reg_write(IXP2000_IRQ_THD_RAW_STATUS_A_0, 0x00ff);

 		if (ixpdev_rx(dev, budget))
 			return 1;
 	} while (ixp2000_reg_read(IXP2000_IRQ_THD_RAW_STATUS_A_0) & 0x00ff);

 	netif_rx_complete(dev);
 	ixp2000_reg_write(IXP2000_IRQ_THD_ENABLE_SET_A_0, 0x00ff);

 	return 0;
 }

 static void ixpdev_tx_complete(void)
 {
 	int channel;
 	u32 wake;

 	wake = 0;
 	while (1) {
 		struct ixpdev_priv *ip;
 		u32 desc;
 		int entry;

 		desc = ixp2000_reg_read(RING_TX_DONE);
 		if (desc == 0)
 			break;

 		/* @@@ Check whether entries come back in order.  */
 		entry = (desc - TX_BUF_DESC_BASE) / sizeof(struct ixpdev_tx_desc);
 		channel = tx_desc[entry].channel;

 		if (channel < 0 || channel >= nds_count) {
 			printk(KERN_ERR "ixp2000: txcomp channel index "
 					"out of bounds (%d, %.8i, %d)\n",
 					channel, (unsigned int)desc, entry);
 			continue;
 		}

 		ip = netdev_priv(nds[channel]);
 		if (ip->tx_queue_entries == TX_BUF_COUNT_PER_CHAN)
 			wake |= 1 << channel;
 		ip->tx_queue_entries--;
 	}

 	for (channel = 0; wake != 0; channel++) {
 		if (wake & (1 << channel)) {
 			netif_wake_queue(nds[channel]);
 			wake &= ~(1 << channel);
 		}
 	}
 }

 static irqreturn_t ixpdev_interrupt(int irq, void *dev_id)
 {
 	u32 status;

 	status = ixp2000_reg_read(IXP2000_IRQ_THD_STATUS_A_0);
 	if (status == 0)
 		return IRQ_NONE;

 	/*
 	 * Any of the eight receive units signaled RX?
 	 */
 	if (status & 0x00ff) {
 		ixp2000_reg_wrb(IXP2000_IRQ_THD_ENABLE_CLEAR_A_0, 0x00ff);
 		if (likely(__netif_rx_schedule_prep(nds[0]))) {
 			__netif_rx_schedule(nds[0]);
 		} else {
 			printk(KERN_CRIT "ixp2000: irq while polling!!\n");
 		}
 	}

 	/*
 	 * Any of the eight transmit units signaled TXdone?
 	 */
 	if (status & 0xff00) {
 		ixp2000_reg_wrb(IXP2000_IRQ_THD_RAW_STATUS_A_0, 0xff00);
 		ixpdev_tx_complete();
 	}

 	return IRQ_HANDLED;
 }

 #ifdef CONFIG_NET_POLL_CONTROLLER
 static void ixpdev_poll_controller(struct net_device *dev)
 {
 	disable_irq(IRQ_IXP2000_THDA0);
 	ixpdev_interrupt(IRQ_IXP2000_THDA0, dev, NULL);
 	enable_irq(IRQ_IXP2000_THDA0);
 }
 #endif

 static int ixpdev_open(struct net_device *dev)
 {
 	struct ixpdev_priv *ip = netdev_priv(dev);
 	int err;

 	if (!nds_open++) {
 		err = request_irq(IRQ_IXP2000_THDA0, ixpdev_interrupt,
 					IRQF_SHARED, "ixp2000_eth", nds);
 		if (err) {
 			nds_open--;
 			return err;
 		}

 		ixp2000_reg_write(IXP2000_IRQ_THD_ENABLE_SET_A_0, 0xffff);
 	}

 	set_port_admin_status(ip->channel, 1);
 	netif_start_queue(dev);

 	return 0;
 }

 static int ixpdev_close(struct net_device *dev)
 {
 	struct ixpdev_priv *ip = netdev_priv(dev);

 	netif_stop_queue(dev);
 	set_port_admin_status(ip->channel, 0);

 	if (!--nds_open) {
 		ixp2000_reg_write(IXP2000_IRQ_THD_ENABLE_CLEAR_A_0, 0xffff);
 		free_irq(IRQ_IXP2000_THDA0, nds);
 	}

 	return 0;
 }

 struct net_device *ixpdev_alloc(int channel, int sizeof_priv)
 {
 	struct net_device *dev;
 	struct ixpdev_priv *ip;

 	dev = alloc_etherdev(sizeof_priv);
 	if (dev == NULL)
 		return NULL;

 	dev->hard_start_xmit = ixpdev_xmit;
 	dev->poll = ixpdev_poll;
 	dev->open = ixpdev_open;
 	dev->stop = ixpdev_close;
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	dev->poll_controller = ixpdev_poll_controller;
 #endif

 	dev->features |= NETIF_F_SG | NETIF_F_HW_CSUM;
 	dev->weight = 64;

 	ip = netdev_priv(dev);
 	ip->channel = channel;
 	ip->tx_queue_entries = 0;

 	return dev;
 }

 int ixpdev_init(int __nds_count, struct net_device **__nds,
 		void (*__set_port_admin_status)(int port, int up))
 {
 	int i;
 	int err;

 	BUILD_BUG_ON(RX_BUF_COUNT > 192 || TX_BUF_COUNT > 192);

 	printk(KERN_INFO "IXP2000 MSF ethernet driver %s\n", DRV_MODULE_VERSION);

 	nds_count = __nds_count;
 	nds = __nds;
 	set_port_admin_status = __set_port_admin_status;

 	for (i = 0; i < RX_BUF_COUNT; i++) {
 		void *buf;

 		buf = (void *)get_zeroed_page(GFP_KERNEL);
 		if (buf == NULL) {
 			err = -ENOMEM;
 			while (--i >= 0)
 				free_page((unsigned long)phys_to_virt(rx_desc[i].buf_addr));
 			goto err_out;
 		}
 		rx_desc[i].buf_addr = virt_to_phys(buf);
 		rx_desc[i].buf_length = PAGE_SIZE;
 	}

 	/* @@@ Maybe we shouldn't be preallocating TX buffers.  */
 	for (i = 0; i < TX_BUF_COUNT; i++) {
 		void *buf;

 		buf = (void *)get_zeroed_page(GFP_KERNEL);
 		if (buf == NULL) {
 			err = -ENOMEM;
 			while (--i >= 0)
 				free_page((unsigned long)phys_to_virt(tx_desc[i].buf_addr));
 			goto err_free_rx;
 		}
 		tx_desc[i].buf_addr = virt_to_phys(buf);
 	}

 	/* 256 entries, ring status set means 'empty', base address 0x0000.  */
 	ixp2000_reg_write(RING_RX_PENDING_BASE, 0x44000000);
 	ixp2000_reg_write(RING_RX_PENDING_HEAD, 0x00000000);
 	ixp2000_reg_write(RING_RX_PENDING_TAIL, 0x00000000);

 	/* 256 entries, ring status set means 'full', base address 0x0400.  */
 	ixp2000_reg_write(RING_RX_DONE_BASE, 0x40000400);
 	ixp2000_reg_write(RING_RX_DONE_HEAD, 0x00000000);
 	ixp2000_reg_write(RING_RX_DONE_TAIL, 0x00000000);

 	for (i = 0; i < RX_BUF_COUNT; i++) {
 		ixp2000_reg_write(RING_RX_PENDING,
 			RX_BUF_DESC_BASE + (i * sizeof(struct ixpdev_rx_desc)));
 	}

 	ixp2000_uengine_load(0, &ixp2400_rx);
 	ixp2000_uengine_start_contexts(0, 0xff);

 	/* 256 entries, ring status set means 'empty', base address 0x0800.  */
 	ixp2000_reg_write(RING_TX_PENDING_BASE, 0x44000800);
 	ixp2000_reg_write(RING_TX_PENDING_HEAD, 0x00000000);
 	ixp2000_reg_write(RING_TX_PENDING_TAIL, 0x00000000);

 	/* 256 entries, ring status set means 'full', base address 0x0c00.  */
 	ixp2000_reg_write(RING_TX_DONE_BASE, 0x40000c00);
 	ixp2000_reg_write(RING_TX_DONE_HEAD, 0x00000000);
 	ixp2000_reg_write(RING_TX_DONE_TAIL, 0x00000000);

 	ixp2000_uengine_load(1, &ixp2400_tx);
 	ixp2000_uengine_start_contexts(1, 0xff);

 	for (i = 0; i < nds_count; i++) {
 		err = register_netdev(nds[i]);
 		if (err) {
 			while (--i >= 0)
 				unregister_netdev(nds[i]);
 			goto err_free_tx;
 		}
 	}

 	for (i = 0; i < nds_count; i++) {
 		printk(KERN_INFO "%s: IXP2000 MSF ethernet (port %d), "
 			"%.2x:%.2x:%.2x:%.2x:%.2x:%.2x.\n", nds[i]->name, i,
 			nds[i]->dev_addr[0], nds[i]->dev_addr[1],
 			nds[i]->dev_addr[2], nds[i]->dev_addr[3],
 			nds[i]->dev_addr[4], nds[i]->dev_addr[5]);
 	}

 	return 0;

 err_free_tx:
 	for (i = 0; i < TX_BUF_COUNT; i++)
 		free_page((unsigned long)phys_to_virt(tx_desc[i].buf_addr));

 err_free_rx:
 	for (i = 0; i < RX_BUF_COUNT; i++)
 		free_page((unsigned long)phys_to_virt(rx_desc[i].buf_addr));

 err_out:
 	return err;
 }

 void ixpdev_deinit(void)
 {
 	int i;

 	/* @@@ Flush out pending packets.  */

 	for (i = 0; i < nds_count; i++)
 		unregister_netdev(nds[i]);

 	ixp2000_uengine_stop_contexts(1, 0xff);
 	ixp2000_uengine_stop_contexts(0, 0xff);
 	ixp2000_uengine_reset(0x3);

 	for (i = 0; i < TX_BUF_COUNT; i++)
 		free_page((unsigned long)phys_to_virt(tx_desc[i].buf_addr));

 	for (i = 0; i < RX_BUF_COUNT; i++)
 		free_page((unsigned long)phys_to_virt(rx_desc[i].buf_addr));
 }
	/*
	* IXP2000 MSF network device driver
	* Copyright (C) 2004, 2005 Lennert Buytenhek <buytenh@wantstofly.org>
	* Dedicated to Marija Kulikova.
	*
	* 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.
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/netdevice.h>
	#include <linux/etherdevice.h>
	#include <linux/init.h>
	#include <linux/moduleparam.h>
	#include <asm/hardware/uengine.h>
	#include <asm/mach-types.h>
	#include <asm/io.h>
	#include "ixp2400_rx.ucode"
	#include "ixp2400_tx.ucode"
	#include "ixpdev_priv.h"
	#include "ixpdev.h"

	#define DRV_MODULE_VERSION "0.2"

	static int nds_count;
	static struct net_device **nds;
	static int nds_open;
	static void (*set_port_admin_status)(int port, int up);

	static struct ixpdev_rx_desc * const rx_desc =
	(struct ixpdev_rx_desc *)(IXP2000_SRAM0_VIRT_BASE + RX_BUF_DESC_BASE);
	static struct ixpdev_tx_desc * const tx_desc =
	(struct ixpdev_tx_desc *)(IXP2000_SRAM0_VIRT_BASE + TX_BUF_DESC_BASE);
	static int tx_pointer;


	static int ixpdev_xmit(struct sk_buff skb, struct net_device dev)
	{
	struct ixpdev_priv *ip = netdev_priv(dev);
	struct ixpdev_tx_desc *desc;
	int entry;

	if (unlikely(skb->len > PAGE_SIZE)) {
	/* @@@ Count drops. */
	dev_kfree_skb(skb);
	return 0;
	}

	entry = tx_pointer;
	tx_pointer = (tx_pointer + 1) % TX_BUF_COUNT;

	desc = tx_desc + entry;
	desc->pkt_length = skb->len;
	desc->channel = ip->channel;

	skb_copy_and_csum_dev(skb, phys_to_virt(desc->buf_addr));
	dev_kfree_skb(skb);

	ixp2000_reg_write(RING_TX_PENDING,
	TX_BUF_DESC_BASE + (entry * sizeof(struct ixpdev_tx_desc)));

	dev->trans_start = jiffies;

	local_irq_disable();
	ip->tx_queue_entries++;
	if (ip->tx_queue_entries == TX_BUF_COUNT_PER_CHAN)
	netif_stop_queue(dev);
	local_irq_enable();

	return 0;
	}


	static int ixpdev_rx(struct net_device dev, int budget)
	{
	while (*budget > 0) {
	struct ixpdev_rx_desc *desc;
	struct sk_buff *skb;
	void *buf;
	u32 _desc;

	_desc = ixp2000_reg_read(RING_RX_DONE);
	if (_desc == 0)
	return 0;

	desc = rx_desc +
	((_desc - RX_BUF_DESC_BASE) / sizeof(struct ixpdev_rx_desc));
	buf = phys_to_virt(desc->buf_addr);

	if (desc->pkt_length < 4 \|\| desc->pkt_length > PAGE_SIZE) {
	printk(KERN_ERR "ixp2000: rx err, length %d\n",
	desc->pkt_length);
	goto err;
	}

	if (desc->channel < 0 \|\| desc->channel >= nds_count) {
	printk(KERN_ERR "ixp2000: rx err, channel %d\n",
	desc->channel);
	goto err;
	}

	/* @@@ Make FCS stripping configurable. */
	desc->pkt_length -= 4;

	if (unlikely(!netif_running(nds[desc->channel])))
	goto err;

	skb = dev_alloc_skb(desc->pkt_length + 2);
	if (likely(skb != NULL)) {
	skb->dev = nds[desc->channel];
	skb_reserve(skb, 2);
	eth_copy_and_sum(skb, buf, desc->pkt_length, 0);
	skb_put(skb, desc->pkt_length);
	skb->protocol = eth_type_trans(skb, skb->dev);

	skb->dev->last_rx = jiffies;

	netif_receive_skb(skb);
	}

	err:
	ixp2000_reg_write(RING_RX_PENDING, _desc);
	dev->quota--;
	(*budget)--;
	}

	return 1;
	}

	/* dev always points to nds[0]. */
	static int ixpdev_poll(struct net_device dev, int budget)
	{
	/* @@@ Have to stop polling when nds[0] is administratively
	* downed while we are polling. */
	do {
	ixp2000_reg_write(IXP2000_IRQ_THD_RAW_STATUS_A_0, 0x00ff);

	if (ixpdev_rx(dev, budget))
	return 1;
	} while (ixp2000_reg_read(IXP2000_IRQ_THD_RAW_STATUS_A_0) & 0x00ff);

	netif_rx_complete(dev);
	ixp2000_reg_write(IXP2000_IRQ_THD_ENABLE_SET_A_0, 0x00ff);

	return 0;
	}

	static void ixpdev_tx_complete(void)
	{
	int channel;
	u32 wake;

	wake = 0;
	while (1) {
	struct ixpdev_priv *ip;
	u32 desc;
	int entry;

	desc = ixp2000_reg_read(RING_TX_DONE);
	if (desc == 0)
	break;

	/* @@@ Check whether entries come back in order. */
	entry = (desc - TX_BUF_DESC_BASE) / sizeof(struct ixpdev_tx_desc);
	channel = tx_desc[entry].channel;

	if (channel < 0 \|\| channel >= nds_count) {
	printk(KERN_ERR "ixp2000: txcomp channel index "
	"out of bounds (%d, %.8i, %d)\n",
	channel, (unsigned int)desc, entry);
	continue;
	}

	ip = netdev_priv(nds[channel]);
	if (ip->tx_queue_entries == TX_BUF_COUNT_PER_CHAN)
	wake \|= 1 << channel;
	ip->tx_queue_entries--;
	}

	for (channel = 0; wake != 0; channel++) {
	if (wake & (1 << channel)) {
	netif_wake_queue(nds[channel]);
	wake &= ~(1 << channel);
	}
	}
	}

	static irqreturn_t ixpdev_interrupt(int irq, void *dev_id)
	{
	u32 status;

	status = ixp2000_reg_read(IXP2000_IRQ_THD_STATUS_A_0);
	if (status == 0)
	return IRQ_NONE;

	/*
	* Any of the eight receive units signaled RX?
	*/
	if (status & 0x00ff) {
	ixp2000_reg_wrb(IXP2000_IRQ_THD_ENABLE_CLEAR_A_0, 0x00ff);
	if (likely(__netif_rx_schedule_prep(nds[0]))) {
	__netif_rx_schedule(nds[0]);
	} else {
	printk(KERN_CRIT "ixp2000: irq while polling!!\n");
	}
	}

	/*
	* Any of the eight transmit units signaled TXdone?
	*/
	if (status & 0xff00) {
	ixp2000_reg_wrb(IXP2000_IRQ_THD_RAW_STATUS_A_0, 0xff00);
	ixpdev_tx_complete();
	}

	return IRQ_HANDLED;
	}

	#ifdef CONFIG_NET_POLL_CONTROLLER
	static void ixpdev_poll_controller(struct net_device *dev)
	{
	disable_irq(IRQ_IXP2000_THDA0);
	ixpdev_interrupt(IRQ_IXP2000_THDA0, dev, NULL);
	enable_irq(IRQ_IXP2000_THDA0);
	}
	#endif

	static int ixpdev_open(struct net_device *dev)
	{
	struct ixpdev_priv *ip = netdev_priv(dev);
	int err;

	if (!nds_open++) {
	err = request_irq(IRQ_IXP2000_THDA0, ixpdev_interrupt,
	IRQF_SHARED, "ixp2000_eth", nds);
	if (err) {
	nds_open--;
	return err;
	}

	ixp2000_reg_write(IXP2000_IRQ_THD_ENABLE_SET_A_0, 0xffff);
	}

	set_port_admin_status(ip->channel, 1);
	netif_start_queue(dev);

	return 0;
	}

	static int ixpdev_close(struct net_device *dev)
	{
	struct ixpdev_priv *ip = netdev_priv(dev);

	netif_stop_queue(dev);
	set_port_admin_status(ip->channel, 0);

	if (!--nds_open) {
	ixp2000_reg_write(IXP2000_IRQ_THD_ENABLE_CLEAR_A_0, 0xffff);
	free_irq(IRQ_IXP2000_THDA0, nds);
	}

	return 0;
	}

	struct net_device *ixpdev_alloc(int channel, int sizeof_priv)
	{
	struct net_device *dev;
	struct ixpdev_priv *ip;

	dev = alloc_etherdev(sizeof_priv);
	if (dev == NULL)
	return NULL;

	dev->hard_start_xmit = ixpdev_xmit;
	dev->poll = ixpdev_poll;
	dev->open = ixpdev_open;
	dev->stop = ixpdev_close;
	#ifdef CONFIG_NET_POLL_CONTROLLER
	dev->poll_controller = ixpdev_poll_controller;
	#endif

	dev->features \|= NETIF_F_SG \| NETIF_F_HW_CSUM;
	dev->weight = 64;

	ip = netdev_priv(dev);
	ip->channel = channel;
	ip->tx_queue_entries = 0;

	return dev;
	}

	int ixpdev_init(int __nds_count, struct net_device **__nds,
	void (*__set_port_admin_status)(int port, int up))
	{
	int i;
	int err;

	BUILD_BUG_ON(RX_BUF_COUNT > 192 \|\| TX_BUF_COUNT > 192);

	printk(KERN_INFO "IXP2000 MSF ethernet driver %s\n", DRV_MODULE_VERSION);

	nds_count = __nds_count;
	nds = __nds;
	set_port_admin_status = __set_port_admin_status;

	for (i = 0; i < RX_BUF_COUNT; i++) {
	void *buf;

	buf = (void *)get_zeroed_page(GFP_KERNEL);
	if (buf == NULL) {
	err = -ENOMEM;
	while (--i >= 0)
	free_page((unsigned long)phys_to_virt(rx_desc[i].buf_addr));
	goto err_out;
	}
	rx_desc[i].buf_addr = virt_to_phys(buf);
	rx_desc[i].buf_length = PAGE_SIZE;
	}

	/* @@@ Maybe we shouldn't be preallocating TX buffers. */
	for (i = 0; i < TX_BUF_COUNT; i++) {
	void *buf;

	buf = (void *)get_zeroed_page(GFP_KERNEL);
	if (buf == NULL) {
	err = -ENOMEM;
	while (--i >= 0)
	free_page((unsigned long)phys_to_virt(tx_desc[i].buf_addr));
	goto err_free_rx;
	}
	tx_desc[i].buf_addr = virt_to_phys(buf);
	}

	/* 256 entries, ring status set means 'empty', base address 0x0000. */
	ixp2000_reg_write(RING_RX_PENDING_BASE, 0x44000000);
	ixp2000_reg_write(RING_RX_PENDING_HEAD, 0x00000000);
	ixp2000_reg_write(RING_RX_PENDING_TAIL, 0x00000000);

	/* 256 entries, ring status set means 'full', base address 0x0400. */
	ixp2000_reg_write(RING_RX_DONE_BASE, 0x40000400);
	ixp2000_reg_write(RING_RX_DONE_HEAD, 0x00000000);
	ixp2000_reg_write(RING_RX_DONE_TAIL, 0x00000000);

	for (i = 0; i < RX_BUF_COUNT; i++) {
	ixp2000_reg_write(RING_RX_PENDING,
	RX_BUF_DESC_BASE + (i * sizeof(struct ixpdev_rx_desc)));
	}

	ixp2000_uengine_load(0, &ixp2400_rx);
	ixp2000_uengine_start_contexts(0, 0xff);

	/* 256 entries, ring status set means 'empty', base address 0x0800. */
	ixp2000_reg_write(RING_TX_PENDING_BASE, 0x44000800);
	ixp2000_reg_write(RING_TX_PENDING_HEAD, 0x00000000);
	ixp2000_reg_write(RING_TX_PENDING_TAIL, 0x00000000);

	/* 256 entries, ring status set means 'full', base address 0x0c00. */
	ixp2000_reg_write(RING_TX_DONE_BASE, 0x40000c00);
	ixp2000_reg_write(RING_TX_DONE_HEAD, 0x00000000);
	ixp2000_reg_write(RING_TX_DONE_TAIL, 0x00000000);

	ixp2000_uengine_load(1, &ixp2400_tx);
	ixp2000_uengine_start_contexts(1, 0xff);

	for (i = 0; i < nds_count; i++) {
	err = register_netdev(nds[i]);
	if (err) {
	while (--i >= 0)
	unregister_netdev(nds[i]);
	goto err_free_tx;
	}
	}

	for (i = 0; i < nds_count; i++) {
	printk(KERN_INFO "%s: IXP2000 MSF ethernet (port %d), "
	"%.2x:%.2x:%.2x:%.2x:%.2x:%.2x.\n", nds[i]->name, i,
	nds[i]->dev_addr[0], nds[i]->dev_addr[1],
	nds[i]->dev_addr[2], nds[i]->dev_addr[3],
	nds[i]->dev_addr[4], nds[i]->dev_addr[5]);
	}

	return 0;

	err_free_tx:
	for (i = 0; i < TX_BUF_COUNT; i++)
	free_page((unsigned long)phys_to_virt(tx_desc[i].buf_addr));

	err_free_rx:
	for (i = 0; i < RX_BUF_COUNT; i++)
	free_page((unsigned long)phys_to_virt(rx_desc[i].buf_addr));

	err_out:
	return err;
	}

	void ixpdev_deinit(void)
	{
	int i;

	/* @@@ Flush out pending packets. */

	for (i = 0; i < nds_count; i++)
	unregister_netdev(nds[i]);

	ixp2000_uengine_stop_contexts(1, 0xff);
	ixp2000_uengine_stop_contexts(0, 0xff);
	ixp2000_uengine_reset(0x3);

	for (i = 0; i < TX_BUF_COUNT; i++)
	free_page((unsigned long)phys_to_virt(tx_desc[i].buf_addr));

	for (i = 0; i < RX_BUF_COUNT; i++)
	free_page((unsigned long)phys_to_virt(rx_desc[i].buf_addr));
	}