patch-2.0.34 linux/drivers/net/epic100.c

• Lines: 1180
• Date: Wed Jun 3 15:17:47 1998
• Orig file: v2.0.33/linux/drivers/net/epic100.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.0.33/linux/drivers/net/epic100.c linux/drivers/net/epic100.c
@@ -0,0 +1,1179 @@
+/* epic100.c: A SMC 83c170 EPIC/100 fast ethernet driver for Linux. */
+/*
+	Written 1997-1998 by Donald Becker.
+
+	This software may be used and distributed according to the terms
+	of the GNU Public License, incorporated herein by reference.
+    All other rights reserved.
+
+	This driver is for the SMC83c170/175 "EPIC" series, as used on the
+	SMC EtherPower II 9432 PCI adapter, and several CardBus cards.
+
+	The author may be reached as becker@CESDIS.gsfc.nasa.gov, or C/O
+	Center of Excellence in Space Data and Information Sciences
+	   Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771
+
+	Support and updates available at
+	http://cesdis.gsfc.nasa.gov/linux/drivers/epic100.html
+*/
+
+static const char *version =
+"epic100.c:v0.99B 4/7/98 Donald Becker http://cesdis.gsfc.nasa.gov/linux/drivers/epic100.html\n";
+
+/* A few user-configurable values. */
+
+/* Keep the ring sizes a power of two for efficiency.
+   Making the Tx ring too large decreases the effectiveness of channel
+   bonding and packet priority.
+   There are no ill effects from too-large receive rings. */
+#define TX_RING_SIZE	16
+#define RX_RING_SIZE	32
+
+/* Set the copy breakpoint for the copy-only-tiny-frames scheme.
+   Setting to > 1518 effectively disables this feature. */
+static int rx_copybreak = 200;
+
+/* Maximum events (Rx packets, etc.) to handle at each interrupt. */
+static int max_interrupt_work = 10;
+
+/* Operational parameters that usually are not changed. */
+/* Time in jiffies before concluding the transmitter is hung. */
+#define TX_TIMEOUT  ((2000*HZ)/1000)
+
+#define PKT_BUF_SZ		1536			/* Size of each temporary Rx buffer.*/
+
+/* Bytes transferred to chip before transmission starts. */
+#define TX_FIFO_THRESH 128		/* Rounded down to 4 byte units. */
+#define RX_FIFO_THRESH 1		/* 0-3, 0==32, 64,96, or 3==128 bytes  */
+
+#include <linux/config.h>
+#ifdef MODULE
+#ifdef MODVERSIONS
+#include <linux/modversions.h>
+#endif
+#include <linux/module.h>
+#include <linux/version.h>
+#else
+#define MOD_INC_USE_COUNT
+#define MOD_DEC_USE_COUNT
+#endif
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/timer.h>
+#include <linux/ptrace.h>
+#include <linux/errno.h>
+#include <linux/ioport.h>
+#include <linux/malloc.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/bios32.h>
+#include <linux/delay.h>
+
+#include <asm/processor.h>		/* Processor type for cache alignment. */
+#include <asm/bitops.h>
+#include <asm/io.h>
+#include <asm/dma.h>
+
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+
+#define RUN_AT(x) (jiffies + (x))
+
+#if LINUX_VERSION_CODE < 0x20138
+#define test_and_set_bit(val, addr) set_bit(val, addr)
+#endif
+#if defined(MODULE) && (LINUX_VERSION_CODE >= 0x20115)
+MODULE_AUTHOR("Donald Becker <becker@cesdis.gsfc.nasa.gov>");
+MODULE_DESCRIPTION("SMC 83c170 EPIC series Ethernet driver");
+MODULE_PARM(debug, "i");
+MODULE_PARM(options, "1-" __MODULE_STRING(8) "i");
+MODULE_PARM(full_duplex, "1-" __MODULE_STRING(8) "i");
+MODULE_PARM(rx_copybreak, "i");
+MODULE_PARM(max_interrupt_work, "i");
+#endif
+
+/* The I/O extent. */
+#define EPIC_TOTAL_SIZE 0x100
+
+static int epic_debug = 1;
+
+/*
+				Theory of Operation
+
+I. Board Compatibility
+
+This device driver is designed for the SMC "EPCI/100", the SMC
+single-chip ethernet controllers for PCI.  This chip is used on
+the SMC EtherPower II boards.
+
+
+II. Board-specific settings
+
+PCI bus devices are configured by the system at boot time, so no jumpers
+need to be set on the board.  The system BIOS will assign the
+PCI INTA signal to a (preferably otherwise unused) system IRQ line.
+Note: Kernel versions earlier than 1.3.73 do not support shared PCI
+interrupt lines.
+
+III. Driver operation
+
+IIIa. Ring buffers
+
+IVb. References
+
+http://www.smc.com/components/catalog/smc83c170.html
+http://cesdis.gsfc.nasa.gov/linux/misc/NWay.html
+http://www.national.com/pf/DP/DP83840.html
+
+IVc. Errata
+
+*/
+
+#ifndef PCI_VENDOR_ID_SMC
+#define PCI_VENDOR_ID_SMC			0x10B8
+#endif
+#ifndef PCI_DEVICE_ID_SMC_EPIC100
+#define PCI_DEVICE_ID_SMC_EPIC100	0x0005
+#endif
+
+/* The rest of these values should never change. */
+/* Offsets to registers, using the (ugh) SMC names. */
+enum epic_registers {
+  COMMAND=0, INTSTAT=4, INTMASK=8, GENCTL=0x0C, NVCTL=0x10, EECTL=0x14,
+  TEST1=0x1C, CRCCNT=0x20, ALICNT=0x24, MPCNT=0x28,	/* Rx error counters. */
+  MIICtrl=0x30, MIIData=0x34, MIICfg=0x38,
+  LAN0=64,						/* MAC address. */
+  MC0=80,						/* Multicast filter table. */
+  RxCtrl=96, TxCtrl=112, TxSTAT=0x74,
+  PRxCDAR=0x84, RxSTAT=0xA4, EarlyRx=0xB0, PTxCDAR=0xC4, TxThresh=0xDC,
+};
+
+/* Interrupt register bits, using my own meaningful names. */
+enum IntrStatus {
+  TxIdle=0x40000, RxIdle=0x20000,
+  CntFull=0x0200, TxUnderrun=0x0100,
+  TxEmpty=0x0080, TxDone=0x0020, RxError=0x0010,
+  RxOverflow=0x0008, RxFull=0x0004, RxHeader=0x0002, RxDone=0x0001,
+};
+
+/* The EPIC100 Rx and Tx buffer descriptors. */
+
+struct epic_tx_desc {
+	s16 status;
+	u16 txlength;
+	u32 bufaddr;
+	u16 buflength;
+	u16 control;
+    u32 next;
+};
+
+struct epic_rx_desc {
+	s16 status;
+	u16 rxlength;
+	u32 bufaddr;
+	u32 buflength;
+    u32 next;
+};
+
+struct epic_private {
+	char devname[8];			/* Used only for kernel debugging. */
+	const char *product_name;
+	struct device *next_module;
+
+	/* Rx and Rx rings here so that they remain paragraph aligned. */
+	struct epic_rx_desc rx_ring[RX_RING_SIZE];
+	struct epic_tx_desc tx_ring[TX_RING_SIZE];
+	/* The saved address of a sent-in-place packet/buffer, for skfree(). */
+	struct sk_buff* tx_skbuff[TX_RING_SIZE];
+	/* The addresses of receive-in-place skbuffs. */
+	struct sk_buff* rx_skbuff[RX_RING_SIZE];
+
+	/* Ring pointers. */
+	unsigned int cur_rx, cur_tx;		/* The next free ring entry */
+	unsigned int dirty_rx, dirty_tx;	/* The ring entries to be free()ed. */
+
+	u8 pci_bus, pci_dev_fn;				/* PCI bus location. */
+	u16 chip_id;
+
+	struct enet_statistics stats;
+	struct timer_list timer;			/* Media selection timer. */
+	unsigned char mc_filter[8];
+	signed char phys[4];				/* MII device addresses. */
+	unsigned int tx_full:1;				/* The Tx queue is full. */
+	unsigned int full_duplex:1;			/* Full-duplex operation requested. */
+	unsigned int default_port:4;		/* Last dev->if_port value. */
+	unsigned int media2:4;				/* Secondary monitored media port. */
+	unsigned int medialock:1;			/* Don't sense media type. */
+	unsigned int mediasense:1;			/* Media sensing in progress. */
+	int pad0, pad1;						/* Used for 8-byte alignment */
+};
+
+/* Used to pass the full-duplex flag, etc. */
+#define MAX_UNITS 8
+static int full_duplex[MAX_UNITS] = {-1, -1, -1, -1, -1, -1, -1, -1};
+static int options[MAX_UNITS] = {-1, -1, -1, -1, -1, -1, -1, -1};
+
+static struct device *epic100_probe1(int pci_bus, int pci_devfn,
+									 struct device *dev, int card_idx);
+static int epic_open(struct device *dev);
+static int read_eeprom(int ioaddr, int location);
+static int mii_read(int ioaddr, int phy_id, int location);
+static void epic_timer(unsigned long data);
+static void epic_tx_timeout(struct device *dev);
+static void epic_init_ring(struct device *dev);
+static int epic_start_xmit(struct sk_buff *skb, struct device *dev);
+static int epic_rx(struct device *dev);
+static void epic_interrupt(int irq, void *dev_instance, struct pt_regs *regs);
+static int epic_close(struct device *dev);
+static struct enet_statistics *epic_get_stats(struct device *dev);
+static void set_rx_mode(struct device *dev);
+
+
+/* A list of all installed EPIC devices, for removing the driver module. */
+static struct device *root_epic_dev = NULL;
+
+int epic100_probe(struct device *dev)
+{
+	static int cards_found = 0;
+	static int pci_index = 0;	/* Static, for multiple probe calls. */
+
+	/* Ideally we would detect all network cards in slot order.  That would
+	   be best done a central PCI probe dispatch, which wouldn't work
+	   well with the current structure.  So instead we detect just the
+	   Epic cards in slot order. */
+
+	if (pcibios_present()) {
+		unsigned char pci_bus, pci_device_fn;
+
+		for (;pci_index < 0xff; pci_index++) {
+			u8  pci_latency;
+			u16 pci_command, new_command, vendor, device;
+			u32 pci_ioaddr;
+
+			if (pcibios_find_class (PCI_CLASS_NETWORK_ETHERNET << 8,
+#ifdef REVERSE_PROBE_ORDER
+									0xff - pci_index,
+#else
+									pci_index,
+#endif
+									&pci_bus, &pci_device_fn)
+				!= PCIBIOS_SUCCESSFUL)
+				break;
+			pcibios_read_config_word(pci_bus, pci_device_fn,
+									 PCI_VENDOR_ID, &vendor);
+			pcibios_read_config_word(pci_bus, pci_device_fn,
+									 PCI_DEVICE_ID, &device);
+			if (vendor != PCI_VENDOR_ID_SMC)
+				continue;
+			if (device != PCI_DEVICE_ID_SMC_EPIC100) {
+				printk("Unknown SMC PCI ethernet chip type %4.4x detected:"
+					   " not configured.\n", device);
+				continue;
+			}
+
+			/* Activate the card: fix for brain-damaged Win98 BIOSes. */
+			pcibios_read_config_word(pci_bus, pci_device_fn,
+									 PCI_COMMAND, &pci_command);
+			new_command = pci_command | PCI_COMMAND_MASTER|PCI_COMMAND_IO;
+			if (pci_command != new_command) {
+				printk(KERN_INFO "  The PCI BIOS has not enabled Ethernet"
+					   " device %4.4x-%4.4x."
+					   "  Updating PCI command %4.4x->%4.4x.\n",
+					   vendor, device, pci_command, new_command);
+				pcibios_write_config_word(pci_bus, pci_device_fn,
+										  PCI_COMMAND, new_command);
+			}
+
+			pcibios_read_config_dword(pci_bus, pci_device_fn,
+									  PCI_BASE_ADDRESS_0, &pci_ioaddr);
+			/* Remove I/O space marker in bit 0. */
+			pci_ioaddr &= ~3;
+
+			if (check_region(pci_ioaddr, EPIC_TOTAL_SIZE))
+				continue;
+
+			dev = epic100_probe1(pci_bus, pci_device_fn, dev, cards_found);
+
+			if (dev) {
+				pcibios_read_config_byte(pci_bus, pci_device_fn,
+										 PCI_LATENCY_TIMER, &pci_latency);
+				if (pci_latency < 32) {
+					printk("  PCI latency timer (CFLT) value of %d is "
+						   "unreasonably low, setting to 32.\n", pci_latency);
+					pcibios_write_config_byte(pci_bus, pci_device_fn,
+											  PCI_LATENCY_TIMER, 32);
+				} else if (epic_debug > 1)
+					printk("  PCI latency timer (CFLT) is %#x.\n",
+						   pci_latency);
+				dev = 0;
+				cards_found++;
+			}
+		}
+	}
+
+	return cards_found ? 0 : -ENODEV;
+}
+
+static struct device *epic100_probe1(int bus, int devfn, struct device *dev,
+									 int card_idx)
+{
+	static int did_version = 0;			/* Already printed version info. */
+	struct epic_private *tp;
+	int i, option = 0, duplex = 0;
+	u8 irq;
+	u16 chip_id;
+	u32 ioaddr;
+
+	if (epic_debug > 0  &&  did_version++ == 0)
+		printk(version);
+
+	if (dev && dev->mem_start) {
+		option = dev->mem_start;
+		duplex = (dev->mem_start & 16) ? 1 : 0;
+	} else if (card_idx >= 0  &&  card_idx < MAX_UNITS) {
+		if (options[card_idx] >= 0)
+			option = options[card_idx];
+		if (full_duplex[card_idx] >= 0)
+			duplex = full_duplex[card_idx];
+	}
+
+	dev = init_etherdev(dev, 0);
+
+	pcibios_read_config_dword(bus, devfn, PCI_BASE_ADDRESS_0, &ioaddr);
+	pcibios_read_config_byte(bus, devfn, PCI_INTERRUPT_LINE, &irq);
+	pcibios_read_config_word(bus, devfn, PCI_DEVICE_ID, &chip_id);
+	ioaddr &= ~3;
+
+	printk("%s: SMC EPIC/100 at %#3x, IRQ %d, ", dev->name, ioaddr, irq);
+
+	/* Bring the chip out of low-power mode. */
+	outl(0x0200, ioaddr + GENCTL);
+	/* Magic?!  If we don't set this bit the MII interface won't work. */
+	outl(0x0008, ioaddr + TEST1);
+
+	/* This could also be read from the EEPROM. */
+	for (i = 0; i < 3; i++)
+		((u16 *)dev->dev_addr)[i] = inw(ioaddr + LAN0 + i*4);
+
+	for (i = 0; i < 5; i++)
+		printk("%2.2x:", dev->dev_addr[i]);
+	printk("%2.2x.\n", dev->dev_addr[i]);
+
+	if (epic_debug > 1) {
+	  printk("%s: EEPROM contents\n", dev->name);
+	  for (i = 0; i < 64; i++)
+		printk(" %4.4x%s", read_eeprom(ioaddr, i), i % 16 == 15 ? "\n" : "");
+	}
+
+	/* We do a request_region() to register /proc/ioports info. */
+	request_region(ioaddr, EPIC_TOTAL_SIZE, "SMC EPIC/100");
+
+	dev->base_addr = ioaddr;
+	dev->irq = irq;
+
+	/* The data structures must be quadword aligned. */
+	tp = kmalloc(sizeof(*tp), GFP_KERNEL | GFP_DMA);
+	memset(tp, 0, sizeof(*tp));
+	dev->priv = tp;
+
+	tp->next_module = root_epic_dev;
+	root_epic_dev = dev;
+
+	tp->chip_id = chip_id;
+
+	/* Find the connected MII xcvrs.
+	   Doing this in open() would allow detecting external xcvrs later, but
+	   takes too much time. */
+	{
+		int phy, phy_idx;
+		for (phy = 0, phy_idx = 0; phy < 32 && phy_idx < sizeof(tp->phys);
+			 phy++) {
+			int mii_status = mii_read(ioaddr, phy, 0);
+			if (mii_status != 0xffff  && mii_status != 0x0000) {
+				tp->phys[phy_idx++] = phy;
+				printk("%s: MII transceiver found at address %d.\n",
+					   dev->name, phy);
+			}
+		}
+		if (phy_idx == 0) {
+			printk("%s: ***WARNING***: No MII transceiver found!\n",
+				   dev->name);
+			/* Use the known PHY address of the EPII. */
+			tp->phys[0] = 3;
+		}
+	}
+
+	/* Leave the chip in low-power mode. */
+	outl(0x0008, ioaddr + GENCTL);
+
+	/* The lower four bits are the media type. */
+	tp->full_duplex = duplex;
+	tp->default_port = option;
+	if (tp->default_port)
+		tp->medialock = 1;
+
+	/* The Epic-specific entries in the device structure. */
+	dev->open = &epic_open;
+	dev->hard_start_xmit = &epic_start_xmit;
+	dev->stop = &epic_close;
+	dev->get_stats = &epic_get_stats;
+	dev->set_multicast_list = &set_rx_mode;
+
+	return dev;
+}
+
+/* Serial EEPROM section. */
+
+/*  EEPROM_Ctrl bits. */
+#define EE_SHIFT_CLK	0x04	/* EEPROM shift clock. */
+#define EE_CS			0x02	/* EEPROM chip select. */
+#define EE_DATA_WRITE	0x08	/* EEPROM chip data in. */
+#define EE_WRITE_0		0x01
+#define EE_WRITE_1		0x09
+#define EE_DATA_READ	0x10	/* EEPROM chip data out. */
+#define EE_ENB			(0x0001 | EE_CS)
+
+/* Delay between EEPROM clock transitions.
+   No extra delay is needed with 33Mhz PCI, but 66Mhz is untested.
+ */
+
+#ifdef _LINUX_DELAY_H
+#define eeprom_delay(nanosec)	udelay(1)
+#else
+#define eeprom_delay(nanosec)	do { ; } while (0)
+#endif
+
+/* The EEPROM commands include the alway-set leading bit. */
+#define EE_WRITE_CMD	(5 << 6)
+#define EE_READ_CMD		(6 << 6)
+#define EE_ERASE_CMD	(7 << 6)
+
+static int read_eeprom(int ioaddr, int location)
+{
+	int i;
+	int retval = 0;
+	int ee_addr = ioaddr + EECTL;
+	int read_cmd = location | EE_READ_CMD;
+	
+	outl(EE_ENB & ~EE_CS, ee_addr);
+	outl(EE_ENB, ee_addr);
+	
+	/* Shift the read command bits out. */
+	for (i = 10; i >= 0; i--) {
+		short dataval = (read_cmd & (1 << i)) ? EE_DATA_WRITE : 0;
+		outl(EE_ENB | dataval, ee_addr);
+		eeprom_delay(100);
+		outl(EE_ENB | dataval | EE_SHIFT_CLK, ee_addr);
+		eeprom_delay(150);
+		outl(EE_ENB | dataval, ee_addr);	/* Finish EEPROM a clock tick. */
+		eeprom_delay(250);
+	}
+	outl(EE_ENB, ee_addr);
+	
+	for (i = 16; i > 0; i--) {
+		outl(EE_ENB | EE_SHIFT_CLK, ee_addr);
+		eeprom_delay(100);
+		retval = (retval << 1) | ((inl(ee_addr) & EE_DATA_READ) ? 1 : 0);
+		outl(EE_ENB, ee_addr);
+		eeprom_delay(100);
+	}
+
+	/* Terminate the EEPROM access. */
+	outl(EE_ENB & ~EE_CS, ee_addr);
+	return retval;
+}
+
+#define MII_READOP		1
+#define MII_WRITEOP		2
+static int mii_read(int ioaddr, int phy_id, int location)
+{
+	int i;
+
+	outl((phy_id << 9) | (location << 4) | MII_READOP, ioaddr + MIICtrl);
+	/* Typical operation takes < 50 ticks. */
+	for (i = 4000; i > 0; i--)
+		if ((inl(ioaddr + MIICtrl) & MII_READOP) == 0)
+			break;
+	return inw(ioaddr + MIIData);
+}
+
+
+static int
+epic_open(struct device *dev)
+{
+	struct epic_private *tp = (struct epic_private *)dev->priv;
+	int ioaddr = dev->base_addr;
+	int i;
+	int mii_reg5;
+	int full_duplex = 0;
+
+	/* Soft reset the chip. */
+	outl(0x0001, ioaddr + GENCTL);
+
+	if (request_irq(dev->irq, &epic_interrupt, SA_SHIRQ, "SMC EPIC/100", dev))
+		return -EAGAIN;
+
+	MOD_INC_USE_COUNT;
+
+	epic_init_ring(dev);
+
+	/* This next line by Ken Yamaguchi.. ?? */
+	outl(0x8, ioaddr + 0x1c);
+
+	/* Pull the chip out of low-power mode, enable interrupts, and set for
+	   PCI read multiple. */
+	outl(0x0412 | (RX_FIFO_THRESH<<8), ioaddr + GENCTL);
+
+	for (i = 0; i < 3; i++)
+		outl(((u16*)dev->dev_addr)[i], ioaddr + LAN0 + i*4);
+
+	outl(TX_FIFO_THRESH, ioaddr + TxThresh);
+	full_duplex = tp->full_duplex;
+
+	mii_reg5 = mii_read(ioaddr, tp->phys[0], 5);
+	if (mii_reg5 != 0xffff && (mii_reg5 & 0x0100)) {
+		full_duplex = 1;
+		if (epic_debug > 1)
+			printk("%s: Setting %s-duplex based on MII xcvr %d"
+				   " register read of %4.4x.\n", dev->name,
+				   full_duplex ? "full" : "half", tp->phys[0],
+				   mii_read(ioaddr, tp->phys[0], 5));
+	}
+
+	outl(full_duplex ? 0x7F : 0x79, ioaddr + TxCtrl);
+	outl(virt_to_bus(tp->rx_ring), ioaddr + PRxCDAR);
+	outl(virt_to_bus(tp->tx_ring), ioaddr + PTxCDAR);
+
+	/* Start the chip's Rx process. */
+	set_rx_mode(dev);
+	outl(0x000A, ioaddr + COMMAND);
+
+	dev->tbusy = 0;
+	dev->interrupt = 0;
+	dev->start = 1;
+
+	/* Enable interrupts by setting the interrupt mask. */
+	outl(CntFull | TxUnderrun | TxDone
+		 | RxError | RxOverflow | RxFull | RxHeader | RxDone,
+		 ioaddr + INTMASK);
+
+	if (epic_debug > 1)
+		printk("%s: epic_open() ioaddr %4.4x IRQ %d status %4.4x %s-duplex.\n",
+			   dev->name, ioaddr, dev->irq, inl(ioaddr + GENCTL),
+			   full_duplex ? "full" : "half");
+
+	/* Set the timer to switch to check for link beat and perhaps switch
+	   to an alternate media type. */
+	init_timer(&tp->timer);
+	tp->timer.expires = RUN_AT((24*HZ)/10);			/* 2.4 sec. */
+	tp->timer.data = (unsigned long)dev;
+	tp->timer.function = &epic_timer;				/* timer handler */
+	add_timer(&tp->timer);
+
+	return 0;
+}
+
+static void epic_timer(unsigned long data)
+{
+	struct device *dev = (struct device *)data;
+	struct epic_private *tp = (struct epic_private *)dev->priv;
+	int ioaddr = dev->base_addr;
+	int next_tick = 0;
+
+	if (epic_debug > 3) {
+		printk("%s: Media selection tick, Tx status %8.8x.\n",
+			   dev->name, inl(ioaddr + TxSTAT));
+		printk("%s: Other registers are IntMask %4.4x IntStatus %4.4x RxStatus"
+			   " %4.4x.\n",
+			   dev->name, inl(ioaddr + INTMASK), inl(ioaddr + INTSTAT),
+			   inl(ioaddr + RxSTAT));
+	}
+
+	if (next_tick) {
+		tp->timer.expires = RUN_AT(next_tick);
+		add_timer(&tp->timer);
+	}
+}
+
+static void epic_tx_timeout(struct device *dev)
+{
+	struct epic_private *tp = (struct epic_private *)dev->priv;
+	int ioaddr = dev->base_addr;
+
+	if (epic_debug > 0) {
+		printk("%s: Transmit timeout using MII device, Tx status %4.4x.\n",
+			   dev->name, inw(ioaddr + TxSTAT));
+		if (epic_debug > 1) {
+			printk("%s: Tx indices: dirty_tx %d, cur_tx %d.\n",
+			 dev->name, tp->dirty_tx, tp->cur_tx);
+		}
+	}
+	/* Perhaps stop and restart the chip's Tx processes . */
+	/* Trigger a transmit demand. */
+	outl(0x0004, dev->base_addr + COMMAND);
+
+	dev->trans_start = jiffies;
+	tp->stats.tx_errors++;
+	return;
+}
+
+/* Initialize the Rx and Tx rings, along with various 'dev' bits. */
+static void
+epic_init_ring(struct device *dev)
+{
+	struct epic_private *tp = (struct epic_private *)dev->priv;
+	int i;
+
+	tp->tx_full = 0;
+	tp->cur_rx = tp->cur_tx = 0;
+	tp->dirty_rx = tp->dirty_tx = 0;
+
+	for (i = 0; i < RX_RING_SIZE; i++) {
+		tp->rx_ring[i].status = 0x8000;		/* Owned by Epic chip */
+		tp->rx_ring[i].buflength = PKT_BUF_SZ;
+		{
+			/* Note the receive buffer must be longword aligned.
+			   dev_alloc_skb() provides 16 byte alignment.  But do *not*
+			   use skb_reserve() to align the IP header! */
+			struct sk_buff *skb;
+			skb = dev_alloc_skb(PKT_BUF_SZ);
+			tp->rx_skbuff[i] = skb;
+			if (skb == NULL)
+				break;			/* Bad news!  */
+			skb->dev = dev;			/* Mark as being used by this device. */
+			skb_reserve(skb, 2); /* Align IP on 16 byte boundaries */
+			tp->rx_ring[i].bufaddr = virt_to_bus(skb->tail);
+		}
+		tp->rx_ring[i].next = virt_to_bus(&tp->rx_ring[i+1]);
+	}
+	/* Mark the last entry as wrapping the ring. */
+	tp->rx_ring[i-1].next = virt_to_bus(&tp->rx_ring[0]);
+
+	/* The Tx buffer descriptor is filled in as needed, but we
+	   do need to clear the ownership bit. */
+	for (i = 0; i < TX_RING_SIZE; i++) {
+		tp->tx_skbuff[i] = 0;
+		tp->tx_ring[i].status = 0x0000;
+		tp->tx_ring[i].next = virt_to_bus(&tp->tx_ring[i+1]);
+	}
+	tp->tx_ring[i-1].next = virt_to_bus(&tp->tx_ring[0]);
+}
+
+static int
+epic_start_xmit(struct sk_buff *skb, struct device *dev)
+{
+	struct epic_private *tp = (struct epic_private *)dev->priv;
+	int entry;
+	u32 flag;
+
+	/* Block a timer-based transmit from overlapping.  This could better be
+	   done with atomic_swap(1, dev->tbusy), but set_bit() works as well. */
+	if (test_and_set_bit(0, (void*)&dev->tbusy) != 0) {
+		if (jiffies - dev->trans_start < TX_TIMEOUT)
+			return 1;
+		epic_tx_timeout(dev);
+		return 1;
+	}
+
+	/* Caution: the write order is important here, set the base address
+	   with the "ownership" bits last. */
+
+	/* Calculate the next Tx descriptor entry. */
+	entry = tp->cur_tx % TX_RING_SIZE;
+
+	tp->tx_skbuff[entry] = skb;
+	tp->tx_ring[entry].txlength = (skb->len >= ETH_ZLEN ? skb->len : ETH_ZLEN);
+	tp->tx_ring[entry].bufaddr = virt_to_bus(skb->data);
+	tp->tx_ring[entry].buflength = skb->len;
+
+	if (tp->cur_tx - tp->dirty_tx < TX_RING_SIZE/2) {/* Typical path */
+	  flag = 0x10; /* No interrupt */
+	  clear_bit(0, (void*)&dev->tbusy);
+	} else if (tp->cur_tx - tp->dirty_tx == TX_RING_SIZE/2) {
+	  flag = 0x14; /* Tx-done intr. */
+	  clear_bit(0, (void*)&dev->tbusy);
+	} else if (tp->cur_tx - tp->dirty_tx < TX_RING_SIZE - 2) {
+	  flag = 0x10; /* No Tx-done intr. */
+	  clear_bit(0, (void*)&dev->tbusy);
+	} else {
+	  /* Leave room for two additional entries. */
+	  flag = 0x14; /* Tx-done intr. */
+	  tp->tx_full = 1;
+	}
+
+	tp->tx_ring[entry].control = flag;
+	tp->tx_ring[entry].status = 0x8000;	/* Pass ownership to the chip. */
+	tp->cur_tx++;
+	/* Trigger an immediate transmit demand. */
+	outl(0x0004, dev->base_addr + COMMAND);
+
+	dev->trans_start = jiffies;
+	if (epic_debug > 4)
+		printk("%s: Queued Tx packet size %d to slot %d, "
+			   "flag %2.2x Tx status %8.8x.\n",
+			   dev->name, (int)skb->len, entry, flag,
+			   inl(dev->base_addr + TxSTAT));
+
+	return 0;
+}
+
+/* The interrupt handler does all of the Rx thread work and cleans up
+   after the Tx thread. */
+static void epic_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
+{
+	struct device *dev = (struct device *)dev_instance;
+	struct epic_private *lp;
+	int status, ioaddr, boguscnt = max_interrupt_work;
+
+	ioaddr = dev->base_addr;
+	lp = (struct epic_private *)dev->priv;
+	if (dev->interrupt) {
+		printk("%s: Re-entering the interrupt handler.\n", dev->name);
+		return;
+	}
+	dev->interrupt = 1;
+
+	do {
+		status = inl(ioaddr + INTSTAT);
+		/* Acknowledge all of the current interrupt sources ASAP. */
+		outl(status & 0x00007fff, ioaddr + INTSTAT);
+
+		if (epic_debug > 4)
+			printk("%s: interrupt  interrupt=%#8.8x new intstat=%#8.8x.\n",
+				   dev->name, status, inl(ioaddr + INTSTAT));
+
+		if ((status & (RxDone | TxEmpty | TxDone)) == 0)
+			break;
+
+		if (status & RxDone)			/* Rx interrupt */
+			epic_rx(dev);
+
+		if (status & (TxEmpty | TxDone)) {
+			int dirty_tx;
+
+			for (dirty_tx = lp->dirty_tx; dirty_tx < lp->cur_tx; dirty_tx++) {
+				int entry = dirty_tx % TX_RING_SIZE;
+				int txstatus = lp->tx_ring[entry].status;
+
+				if (txstatus < 0)
+					break;			/* It still hasn't been Txed */
+
+				if ( ! (txstatus & 0x0001)) {
+					/* There was an major error, log it. */
+#ifndef final_version
+					if (epic_debug > 1)
+						printk("%s: Transmit error, Tx status %8.8x.\n",
+							   dev->name, txstatus);
+#endif
+					lp->stats.tx_errors++;
+					if (txstatus & 0x1050) lp->stats.tx_aborted_errors++;
+					if (txstatus & 0x0008) lp->stats.tx_carrier_errors++;
+					if (txstatus & 0x0040) lp->stats.tx_window_errors++;
+					if (txstatus & 0x0010) lp->stats.tx_fifo_errors++;
+#ifdef ETHER_STATS
+					if (txstatus & 0x1000) lp->stats.collisions16++;
+#endif
+				} else {
+#ifdef ETHER_STATS
+					if ((txstatus & 0x0002) != 0) lp->stats.tx_deferred++;
+#endif
+					lp->stats.collisions += (txstatus >> 8) & 15;
+					lp->stats.tx_packets++;
+				}
+
+				/* Free the original skb. */
+				dev_kfree_skb(lp->tx_skbuff[entry], FREE_WRITE);
+				lp->tx_skbuff[entry] = 0;
+			}
+
+#ifndef final_version
+			if (lp->cur_tx - dirty_tx > TX_RING_SIZE) {
+				printk("%s: Out-of-sync dirty pointer, %d vs. %d, full=%d.\n",
+					   dev->name, dirty_tx, lp->cur_tx, lp->tx_full);
+				dirty_tx += TX_RING_SIZE;
+			}
+#endif
+
+			if (lp->tx_full && dev->tbusy
+				&& dirty_tx > lp->cur_tx - TX_RING_SIZE + 2) {
+				/* The ring is no longer full, clear tbusy. */
+				lp->tx_full = 0;
+				clear_bit(0, (void*)&dev->tbusy);
+				mark_bh(NET_BH);
+			}
+
+			lp->dirty_tx = dirty_tx;
+		}
+
+		/* Check uncommon events all at once. */
+		if (status & (CntFull | TxUnderrun | RxOverflow)) {
+			/* Always update the error counts to avoid overhead later. */
+			lp->stats.rx_missed_errors += inb(ioaddr + MPCNT);
+			lp->stats.rx_frame_errors += inb(ioaddr + ALICNT);
+			lp->stats.rx_crc_errors += inb(ioaddr + CRCCNT);
+
+			if (status & TxUnderrun) { /* Tx FIFO underflow. */
+			  lp->stats.tx_fifo_errors++;
+			  /* Restart the transmit process. */
+			  outl(0x0080, ioaddr + COMMAND);
+			}
+			if (status & RxOverflow) {		/* Missed a Rx frame. */
+				lp->stats.rx_errors++;
+			}
+			/* Clear all error sources. */
+			outl(status & 0x7f18, ioaddr + INTSTAT);
+		}
+		if (--boguscnt < 0) {
+			printk("%s: Too much work at interrupt, IntrStatus=0x%8.8x.\n",
+				   dev->name, status);
+			/* Clear all interrupt sources. */
+			outl(0x0001ffff, ioaddr + INTSTAT);
+			break;
+		}
+	} while (1);
+
+	if (epic_debug > 3)
+		printk("%s: exiting interrupt, intr_status=%#4.4x.\n",
+			   dev->name, inl(ioaddr + INTSTAT));
+
+	dev->interrupt = 0;
+	return;
+}
+
+static int
+epic_rx(struct device *dev)
+{
+	struct epic_private *lp = (struct epic_private *)dev->priv;
+	int entry = lp->cur_rx % RX_RING_SIZE;
+
+	if (epic_debug > 4)
+		printk(" In epic_rx(), entry %d %8.8x.\n", entry,
+			   lp->rx_ring[entry].status);
+	/* If we own the next entry, it's a new packet. Send it up. */
+	while (lp->rx_ring[entry].status >= 0) {
+		int status = lp->rx_ring[entry].status;
+
+		if (epic_debug > 4)
+			printk("  epic_rx() status was %8.8x.\n", status);
+		if (status & 0x2000) {
+			printk("%s: Oversized Ethernet frame spanned multiple buffers,"
+				   " status %4.4x!\n", dev->name, status);
+			  lp->stats.rx_length_errors++;
+		} else if (status & 0x0006) {
+			/* Rx Frame errors are counted in hardware. */
+			lp->stats.rx_errors++;
+		} else {
+			/* Malloc up new buffer, compatible with net-2e. */
+			/* Omit the four octet CRC from the length. */
+			short pkt_len = lp->rx_ring[entry].rxlength - 4;
+			struct sk_buff *skb;
+			int rx_in_place = 0;
+
+			/* Check if the packet is long enough to just accept without
+			   copying to a properly sized skbuff. */
+			if (pkt_len > rx_copybreak) {
+				struct sk_buff *newskb;
+				char *temp;
+
+				/* Pass up the skb already on the Rx ring. */
+				skb = lp->rx_skbuff[entry];
+				temp = skb_put(skb, pkt_len);
+				if (bus_to_virt(lp->rx_ring[entry].bufaddr) != temp)
+					printk("%s: Warning -- the skbuff addresses do not match"
+						   " in epic_rx: %p vs. %p / %p.\n", dev->name,
+						   bus_to_virt(lp->rx_ring[entry].bufaddr),
+						   skb->head, temp);
+				/* Get a fresh skbuff to replace the filled one. */
+				newskb = dev_alloc_skb(PKT_BUF_SZ);
+				if (newskb) {
+					rx_in_place = 1;
+					lp->rx_skbuff[entry] = newskb;
+					newskb->dev = dev;
+					/* Align IP on 16 byte boundaries */
+					skb_reserve(newskb, 2);
+					lp->rx_ring[entry].bufaddr = virt_to_bus(newskb->tail);
+				} else			/* No memory, drop the packet. */
+				  skb = 0;
+			} else
+				skb = dev_alloc_skb(pkt_len + 2);
+			if (skb == NULL) {
+				int i;
+				printk("%s: Memory squeeze, deferring packet.\n", dev->name);
+				/* Check that at least two ring entries are free.
+				   If not, free one and mark stats->rx_dropped++. */
+				for (i = 0; i < RX_RING_SIZE; i++)
+					if (lp->rx_ring[(entry+i) % RX_RING_SIZE].status < 0)
+						break;
+
+				if (i > RX_RING_SIZE -2) {
+					lp->stats.rx_dropped++;
+					lp->rx_ring[entry].status = 0x8000;
+					lp->cur_rx++;
+				}
+				break;
+			}
+			skb->dev = dev;
+			if (! rx_in_place) {
+				skb_reserve(skb, 2);	/* 16 byte align the data fields */
+				memcpy(skb_put(skb, pkt_len),
+					   bus_to_virt(lp->rx_ring[entry].bufaddr), pkt_len);
+			}
+			skb->protocol = eth_type_trans(skb, dev);
+			netif_rx(skb);
+			lp->stats.rx_packets++;
+		}
+
+		lp->rx_ring[entry].status = 0x8000;
+		entry = (++lp->cur_rx) % RX_RING_SIZE;
+	}
+
+	return 0;
+}
+
+static int
+epic_close(struct device *dev)
+{
+	int ioaddr = dev->base_addr;
+	struct epic_private *tp = (struct epic_private *)dev->priv;
+	int i;
+
+	dev->start = 0;
+	dev->tbusy = 1;
+
+	if (epic_debug > 1)
+		printk("%s: Shutting down ethercard, status was %2.2x.\n",
+			   dev->name, inl(ioaddr + INTSTAT));
+
+	/* Disable interrupts by clearing the interrupt mask. */
+	outl(0x00000000, ioaddr + INTMASK);
+	/* Stop the chip's Tx and Rx DMA processes. */
+	outw(0x0061, ioaddr + COMMAND);
+
+	/* Update the error counts. */
+	tp->stats.rx_missed_errors += inb(ioaddr + MPCNT);
+	tp->stats.rx_frame_errors += inb(ioaddr + ALICNT);
+	tp->stats.rx_crc_errors += inb(ioaddr + CRCCNT);
+
+	del_timer(&tp->timer);
+
+	free_irq(dev->irq, dev);
+
+	/* Free all the skbuffs in the Rx queue. */
+	for (i = 0; i < RX_RING_SIZE; i++) {
+		struct sk_buff *skb = tp->rx_skbuff[i];
+		tp->rx_skbuff[i] = 0;
+		tp->rx_ring[i].status = 0;		/* Not owned by Epic chip. */
+		tp->rx_ring[i].buflength = 0;
+		tp->rx_ring[i].bufaddr = 0xBADF00D0; /* An invalid address. */
+		if (skb) {
+#if LINUX_VERSION_CODE < 0x20100
+			skb->free = 1;
+#endif
+			dev_kfree_skb(skb, FREE_WRITE);
+		}
+	}
+	for (i = 0; i < TX_RING_SIZE; i++) {
+		if (tp->tx_skbuff[i])
+			dev_kfree_skb(tp->tx_skbuff[i], FREE_WRITE);
+		tp->tx_skbuff[i] = 0;
+	}
+
+
+	/* Green! Leave the chip in low-power mode. */
+	outl(0x0008, ioaddr + GENCTL);
+	
+	MOD_DEC_USE_COUNT;
+
+	return 0;
+}
+
+static struct enet_statistics *
+epic_get_stats(struct device *dev)
+{
+	struct epic_private *tp = (struct epic_private *)dev->priv;
+	int ioaddr = dev->base_addr;
+
+	if (dev->start) {
+		/* Update the error counts. */
+		tp->stats.rx_missed_errors += inb(ioaddr + MPCNT);
+		tp->stats.rx_frame_errors += inb(ioaddr + ALICNT);
+		tp->stats.rx_crc_errors += inb(ioaddr + CRCCNT);
+	}
+
+	return &tp->stats;
+}
+
+/* Set or clear the multicast filter for this adaptor.
+   Note that we only use exclusion around actually queueing the
+   new frame, not around filling tp->setup_frame.  This is non-deterministic
+   when re-entered but still correct. */
+
+/* The little-endian AUTODIN II ethernet CRC calculation.
+   N.B. Do not use for bulk data, use a table-based routine instead.
+   This is common code and should be moved to net/core/crc.c */
+static unsigned const ethernet_polynomial_le = 0xedb88320U;
+static inline unsigned ether_crc_le(int length, unsigned char *data)
+{
+	unsigned int crc = 0xffffffff;	/* Initial value. */
+	while(--length >= 0) {
+		unsigned char current_octet = *data++;
+		int bit;
+		for (bit = 8; --bit >= 0; current_octet >>= 1) {
+			if ((crc ^ current_octet) & 1) {
+				crc >>= 1;
+				crc ^= ethernet_polynomial_le;
+			} else
+				crc >>= 1;
+		}
+	}
+	return crc;
+}
+
+
+static void set_rx_mode(struct device *dev)
+{
+	int ioaddr = dev->base_addr;
+	struct epic_private *tp = (struct epic_private *)dev->priv;
+	unsigned char mc_filter[8];		 /* Multicast hash filter */
+	int i;
+
+	if (dev->flags & IFF_PROMISC) {			/* Set promiscuous. */
+		outl(0x002C, ioaddr + RxCtrl);
+		/* Unconditionally log net taps. */
+		printk("%s: Promiscuous mode enabled.\n", dev->name);
+		memset(mc_filter, 0xff, sizeof(mc_filter));
+	} else if ((dev->mc_count > 0)  ||  (dev->flags & IFF_ALLMULTI)) {
+		/* There is apparently a chip bug, so the multicast filter
+		   is never enabled. */
+		/* Too many to filter perfectly -- accept all multicasts. */
+		memset(mc_filter, 0xff, sizeof(mc_filter));
+		outl(0x000C, ioaddr + RxCtrl);
+	} else if (dev->mc_count == 0) {
+		outl(0x0004, ioaddr + RxCtrl);
+		return;
+	} else {					/* Never executed, for now. */
+		struct dev_mc_list *mclist;
+
+		memset(mc_filter, 0, sizeof(mc_filter));
+		for (i = 0, mclist = dev->mc_list; mclist && i < dev->mc_count;
+			 i++, mclist = mclist->next)
+			set_bit(ether_crc_le(ETH_ALEN, mclist->dmi_addr) & 0x3f,
+					mc_filter);
+	}
+	/* ToDo: perhaps we need to stop the Tx and Rx process here? */
+	if (memcmp(mc_filter, tp->mc_filter, sizeof(mc_filter))) {
+		for (i = 0; i < 4; i++)
+			outw(((u16 *)mc_filter)[i], ioaddr + MC0 + i*4);
+		memcpy(tp->mc_filter, mc_filter, sizeof(mc_filter));
+	}
+	return;
+}
+
+
+#ifdef CARDBUS
+
+#include <pcmcia/driver_ops.h>
+
+static dev_node_t *epic_attach(dev_locator_t *loc)
+{
+	struct device *dev;
+	u16 dev_id;
+	u32 io;
+	u8 bus, devfn, irq;
+
+	if (loc->bus != LOC_PCI) return NULL;
+	bus = loc->b.pci.bus; devfn = loc->b.pci.devfn;
+	printk(KERN_INFO "epic_attach(bus %d, function %d)\n", bus, devfn);
+	pcibios_read_config_dword(bus, devfn, PCI_BASE_ADDRESS_0, &io);
+	pcibios_read_config_byte(bus, devfn, PCI_INTERRUPT_LINE, &irq);
+	pcibios_read_config_word(bus, devfn, PCI_DEVICE_ID, &dev_id);
+	io &= ~3;
+	dev = epic100_probe1(bus, devfn, NULL, -1);
+	if (dev) {
+		dev_node_t *node = kmalloc(sizeof(dev_node_t), GFP_KERNEL);
+		strcpy(node->dev_name, dev->name);
+		node->major = node->minor = 0;
+		node->next = NULL;
+		MOD_INC_USE_COUNT;
+		return node;
+	}
+	return NULL;
+}
+
+static void epic_detach(dev_node_t *node)
+{
+	struct device **devp, **next;
+	printk(KERN_INFO "epic_detach(%s)\n", node->dev_name);
+	for (devp = &root_epic_dev; *devp; devp = next) {
+		next = &((struct epic_private *)(*devp)->priv)->next_module;
+		if (strcmp((*devp)->name, node->dev_name) == 0) break;
+	}
+	if (*devp) {
+		unregister_netdev(*devp);
+		kfree(*devp);
+		*devp = *next;
+		kfree(node);
+		MOD_DEC_USE_COUNT;
+	}
+}
+
+struct driver_operations epic_ops = {
+	"epic_cb", epic_attach, NULL, NULL, epic_detach
+};
+
+#endif  /* Cardbus support */
+
+
+#ifdef MODULE
+
+/* An additional parameter that may be passed in... */
+static int debug = -1;
+
+int
+init_module(void)
+{
+	if (debug >= 0)
+		epic_debug = debug;
+
+#ifdef CARDBUS
+	register_driver(&epic_ops);
+	return 0;
+#else
+	return epic100_probe(0);
+#endif
+}
+
+void
+cleanup_module(void)
+{
+	struct device *next_dev;
+
+#ifdef CARDBUS
+	unregister_driver(&epic_ops);
+#endif
+
+	/* No need to check MOD_IN_USE, as sys_delete_module() checks. */
+	while (root_epic_dev) {
+		next_dev = ((struct epic_private *)root_epic_dev->priv)->next_module;
+		unregister_netdev(root_epic_dev);
+		release_region(root_epic_dev->base_addr, EPIC_TOTAL_SIZE);
+		kfree(root_epic_dev);
+		root_epic_dev = next_dev;
+	}
+}
+
+#endif  /* MODULE */
+
+/*
+ * Local variables:
+ *  compile-command: "gcc -DMODULE -D__KERNEL__ -Wall -Wstrict-prototypes -O6 -c epic100.c"
+ *  alt-compile-command: "gcc -DMODVERSIONS -DMODULE -D__KERNEL__ -Wall -Wstrict-prototypes -O6 -c epic100.c"
+ *  alt-compile-command: "gcc -DCARDBUS -DMODULE -D__KERNEL__ -Wall -Wstrict-prototypes -O6 -c epic.c -o epic_cb.c -I/usr/src/pcmcia-cs-3.0.0/include/"
+ *  c-indent-level: 4
+ *  c-basic-offset: 4
+ *  tab-width: 4
+ * End:
+ */