/* 8390.c: A general NS8390 ethernet driver core for linux. */
/*
  Written 1992,1993 by Donald Becker.
  
  Copyright 1993 United States Government as represented by the
  Director, National Security Agency.	 This software may be used and
  distributed according to the terms of the GNU Public License,
  incorporated herein by reference.
  
  This is the chip-specific code for many 8390-based ethernet adaptors.
  This is not a complete driver, it must be combined with board-specific
  code such as ne.c, wd.c, 3c503.c, etc.
  
  The Author may be reached as becker@super.org or
  C/O Supercomputing Research Ctr., 17100 Science Dr., Bowie MD 20715
  */

static char *version =
    "8390.c:v0.99-15e 2/16/94 Donald Becker (becker@super.org)\n";
#include <linux/config.h>

/*
  Braindamage remaining:
  Much of this code should be cleaned up post-1.00, but it has been
  extensively beta tested in the current form.
  
  Sources:
  The National Semiconductor LAN Databook, and the 3Com 3c503 databook.
  The NE* programming info came from the Crynwr packet driver, and figuring
  out that the those boards are similar to the NatSemi evaluation board
  described in AN-729.	Thanks NS, no thanks to Novell/Eagle.
  */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/string.h>
#include <asm/system.h>
#include <asm/segment.h>
#include <asm/bitops.h>
#include <asm/io.h>
#include <errno.h>
#include <linux/fcntl.h>
#include <linux/in.h>
#include <linux/interrupt.h>

#include "dev.h"
#include "eth.h"
#include "ip.h"
#include "protocol.h"
#include "tcp.h"
#include "skbuff.h"
#include "sock.h"
#include "arp.h"

#include "8390.h"

/* These are the operational function interfaces to board-specific
   routines.
	void reset_8390(struct device *dev)
		Resets the board associated with DEV, including a hardware reset of
		the 8390.  This is only called when there is a transmit timeout, and
		it is always followed by 8390_init().
	void block_output(struct device *dev, int count, const unsigned char *buf,
					  int start_page)
		Write the COUNT bytes of BUF to the packet buffer at START_PAGE.  The
		"page" value uses the 8390's 256-byte pages.
	int block_input(struct device *dev, int count, char *buf, int ring_offset)
		Read COUNT bytes from the packet buffer into BUF.  Start reading from
		RING_OFFSET, the address as the 8390 sees it.  The first read will
		always be the 4 byte, page aligned 8390 header.  *If* there is a
		subsequent read, it will be of the rest of the packet.
*/
#define ei_reset_8390 (ei_local->reset_8390)
#define ei_block_output (ei_local->block_output)
#define ei_block_input (ei_local->block_input)

/* use 0 for production, 1 for verification, >2 for debug */
#ifdef EI_DEBUG
int ei_debug = EI_DEBUG;
#else
int ei_debug = 1;
#endif

/* Max number of packets received at one Intr.
   Current this may only be examined by a kernel debugger. */
static int high_water_mark = 0;

/* Index to functions. */
int ei_open(struct device *dev);	/* Put into the device structure. */
void ei_interrupt(int reg_ptr);		/* Installed as the interrupt handler. */

static void ei_tx_intr(struct device *dev);
static void ei_receive(struct device *dev);
static void ei_rx_overrun(struct device *dev);

/* Routines generic to NS8390-based boards. */
void NS8390_init(struct device *dev, int startp);
static void NS8390_trigger_send(struct device *dev, unsigned int length,
								int start_page);
#ifdef HAVE_MULTICAST
static void set_multicast_list(struct device *dev, int num_addrs, void *addrs);
#endif

struct sigaction ei_sigaction = { ei_interrupt, 0, 0, NULL, };

/* Open/initialize the board.  This routine goes all-out, setting everything
   up anew at each open, even though many of these registers should only
   need to be set once at boot.
   */
int ei_open(struct device *dev)
{
    struct ei_device *ei_local = (struct ei_device *) dev->priv;
    
    if ( ! ei_local) {
		printk("%s: Opening a non-existent physical device\n", dev->name);
		return ENXIO;
    }
    
    irq2dev_map[dev->irq] = dev;
    NS8390_init(dev, 1);
    dev->start = 1;
    ei_local->irqlock = 0;
    return 0;
}

static int ei_start_xmit(struct sk_buff *skb, struct device *dev)
{
    int e8390_base = dev->base_addr;
    struct ei_device *ei_local = (struct ei_device *) dev->priv;
    int length, send_length;
    
	/* We normally shouldn't be called if dev->tbusy is set, but the
	   existing code does anyway.
	   If it has been too long (> 100 or 150ms.) since the last Tx we assume
	   the board has died and kick it. */

    if (dev->tbusy) {	/* Do timeouts, just like the 8003 driver. */
		int txsr = inb(e8390_base+EN0_TSR), isr;
		int tickssofar = jiffies - dev->trans_start;
		if (tickssofar < 10	||	(tickssofar < 15 && ! (txsr & ENTSR_PTX))) {
			return 1;
		}
		isr = inb(e8390_base+EN0_ISR);
		printk("%s: transmit timed out, TX status %#2x, ISR %#2x.\n",
			   dev->name, txsr, isr);
		/* Does the 8390 thinks it has posted an interrupt? */
		if (isr)
			printk("%s: Possible IRQ conflict on IRQ%d?\n", dev->name, dev->irq);
		else {
			/* The 8390 probably hasn't gotten on the cable yet. */
			printk("%s: Possible network cable problem?\n", dev->name);
			ei_local->interface_num ^= 1; 	/* Try a different xcvr.  */
		}
		/* Try to restart the card.  Perhaps the user has fixed something. */
		ei_reset_8390(dev);
		NS8390_init(dev, 1);
		dev->trans_start = jiffies;
    }
    
    /* Sending a NULL skb means some higher layer thinks we've missed an
       tx-done interrupt. Caution: dev_tint() handles the cli()/sti()
       itself. */
    if (skb == NULL) {
		dev_tint(dev);
		return 0;
    }
    /* Fill in the ethernet header. */
    if (!skb->arp  &&  dev->rebuild_header(skb->data, dev)) {
		skb->dev = dev;
		arp_queue (skb);
		return 0;
    }
    skb->arp=1;
    
    length = skb->len;
    if (skb->len <= 0)
		return 0;

	/* Block a timer-based transmit from overlapping. */
	if (set_bit(0, (void*)&dev->tbusy) != 0) {
		printk("%s: Transmitter access conflict.\n", dev->name);
		return 1;
	}

    /* Mask interrupts from the ethercard. */
    outb(0x00,	e8390_base + EN0_IMR);
    ei_local->irqlock = 1;

    send_length = ETH_ZLEN < length ? length : ETH_ZLEN;

    if (ei_local->pingpong) {
		int output_page;
		if (ei_local->tx1 == 0) {
			output_page = ei_local->tx_start_page;
			ei_local->tx1 = send_length;
			if (ei_debug  &&  ei_local->tx2 > 0)
				printk("%s: idle transmitter tx2=%d, lasttx=%d, txing=%d.\n",
					   dev->name, ei_local->tx2, ei_local->lasttx,
					   ei_local->txing);
		} else if (ei_local->tx2 == 0) {
			output_page = ei_local->tx_start_page + 6;
			ei_local->tx2 = send_length;
			if (ei_debug  &&  ei_local->tx1 > 0)
				printk("%s: idle transmitter, tx1=%d, lasttx=%d, txing=%d.\n",
					   dev->name, ei_local->tx1, ei_local->lasttx,
					   ei_local->txing);
		} else {	/* We should never get here. */
			if (ei_debug)
				printk("%s: No packet buffer space for ping-pong use.\n",
					   dev->name);
			ei_local->irqlock = 0;
			dev->tbusy = 1;
			outb_p(ENISR_ALL,  e8390_base + EN0_IMR);
			return 1;
		}
		ei_block_output(dev, length, skb->data, output_page);
		if (! ei_local->txing) {
			NS8390_trigger_send(dev, send_length, output_page);
			dev->trans_start = jiffies;
			if (output_page == ei_local->tx_start_page)
				ei_local->tx1 = -1, ei_local->lasttx = -1;
			else
				ei_local->tx2 = -1, ei_local->lasttx = -2;
			ei_local->txing = 1;
		} else
			ei_local->txqueue++;

		dev->tbusy = (ei_local->tx1  &&  ei_local->tx2);
    } else {  /* No pingpong, just a single Tx buffer. */
		ei_block_output(dev, length, skb->data, ei_local->tx_start_page);
		NS8390_trigger_send(dev, send_length, ei_local->tx_start_page);
		dev->trans_start = jiffies;
		dev->tbusy = 1;
    }
    
    /* Turn 8390 interrupts back on. */
    ei_local->irqlock = 0;
    outb_p(ENISR_ALL, e8390_base + EN0_IMR);

    if (skb->free)
		kfree_skb (skb, FREE_WRITE);
    
    return 0;
}

/* The typical workload of the driver:
   Handle the ether interface interrupts. */
void ei_interrupt(int reg_ptr)
{
    int irq = -(((struct pt_regs *)reg_ptr)->orig_eax+2);
    struct device *dev = (struct device *)(irq2dev_map[irq]);
    int e8390_base;
    int interrupts, boguscount = 0;
    struct ei_device *ei_local;
    
    if (dev == NULL) {
		printk ("net_interrupt(): irq %d for unknown device.\n", irq);
		return;
    }
    e8390_base = dev->base_addr;
    ei_local = (struct ei_device *) dev->priv;
    if (dev->interrupt || ei_local->irqlock) {
		/* The "irqlock" check is only for testing. */
		sti();
		printk(ei_local->irqlock
			   ? "%s: Interrupted while interrupts are masked! isr=%#2x imr=%#2x.\n"
			   : "%s: Reentering the interrupt handler! isr=%#2x imr=%#2x.\n",
			   dev->name, inb_p(e8390_base + EN0_ISR),
			   inb_p(e8390_base + EN0_IMR));
		return;
    }
    
    dev->interrupt = 1;
    sti(); /* Allow other interrupts. */
    
    /* Change to page 0 and read the intr status reg. */
    outb_p(E8390_NODMA+E8390_PAGE0, e8390_base + E8390_CMD);
    if (ei_debug > 3)
		printk("%s: interrupt(isr=%#2.2x).\n", dev->name,
			   inb_p(e8390_base + EN0_ISR));
    
    /* !!Assumption!! -- we stay in page 0.	 Don't break this. */
    while ((interrupts = inb_p(e8390_base + EN0_ISR)) != 0
		   && ++boguscount < 5) {
		if (interrupts & ENISR_RDC) {
			/* Ack meaningless DMA complete. */
			outb_p(ENISR_RDC, e8390_base + EN0_ISR);
		}
		if (interrupts & ENISR_OVER) {
			ei_rx_overrun(dev);
		} else if (interrupts & (ENISR_RX+ENISR_RX_ERR)) {
			/* Got a good (?) packet. */
			ei_receive(dev);
		}
		/* Push the next to-transmit packet through. */
		if (interrupts & ENISR_TX) {
			ei_tx_intr(dev);
		} else if (interrupts & ENISR_COUNTERS) {
			struct ei_device *ei_local = (struct ei_device *) dev->priv;
			ei_local->stat.rx_frame_errors += inb_p(e8390_base + EN0_COUNTER0);
			ei_local->stat.rx_crc_errors   += inb_p(e8390_base + EN0_COUNTER1);
			ei_local->stat.rx_missed_errors+= inb_p(e8390_base + EN0_COUNTER2);
			outb_p(ENISR_COUNTERS, e8390_base + EN0_ISR); /* Ack intr. */
		}
		
		/* Ignore the transmit errs and reset intr for now. */
		if (interrupts & ENISR_TX_ERR) {
			outb_p(ENISR_TX_ERR, e8390_base + EN0_ISR); /* Ack intr. */
		}
		outb_p(E8390_NODMA+E8390_PAGE0+E8390_START, e8390_base + E8390_CMD);
    }
    
    if (interrupts && ei_debug) {
		printk("%s: unknown interrupt %#2x\n", dev->name, interrupts);
		outb_p(E8390_NODMA+E8390_PAGE0+E8390_START, e8390_base + E8390_CMD);
		outb_p(0xff, e8390_base + EN0_ISR); /* Ack. all intrs. */
    }
    dev->interrupt = 0;
    return;
}

/* We have finished a transmit: check for errors and then trigger the next
   packet to be sent. */
static void ei_tx_intr(struct device *dev)
{
    int e8390_base = dev->base_addr;
    int status = inb(e8390_base + EN0_TSR);
    struct ei_device *ei_local = (struct ei_device *) dev->priv;
    
    outb_p(ENISR_TX, e8390_base + EN0_ISR); /* Ack intr. */
    
    if (ei_local->pingpong) {
		ei_local->txqueue--;
		if (ei_local->tx1 < 0) {
			if (ei_local->lasttx != 1 && ei_local->lasttx != -1)
				printk("%s: bogus last_tx_buffer %d, tx1=%d.\n",
					   ei_local->name, ei_local->lasttx, ei_local->tx1);
			ei_local->tx1 = 0;
			dev->tbusy = 0;
			if (ei_local->tx2 > 0) {
				NS8390_trigger_send(dev, ei_local->tx2, ei_local->tx_start_page + 6);
				dev->trans_start = jiffies;
				ei_local->txing = 1;
				ei_local->tx2 = -1,
				ei_local->lasttx = 2;
			} else
				ei_local->lasttx = 20, ei_local->txing = 0;
		} else if (ei_local->tx2 < 0) {
			if (ei_local->lasttx != 2  &&  ei_local->lasttx != -2)
				printk("%s: bogus last_tx_buffer %d, tx2=%d.\n",
					   ei_local->name, ei_local->lasttx, ei_local->tx2);
			ei_local->tx2 = 0;
			dev->tbusy = 0;
			if (ei_local->tx1 > 0) {
				NS8390_trigger_send(dev, ei_local->tx1, ei_local->tx_start_page);
				dev->trans_start = jiffies;
				ei_local->txing = 1;
				ei_local->tx1 = -1;
				ei_local->lasttx = 1;
			} else