8390.c

嵌入式系统的TCP/IP源代码

/* 8390.c: A general NS8390 ethernet driver core for linux. */
/*
	Written 1992-94 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.

	The author may be reached as [e-mail], or C/O
	Center of Excellence in Space Data and Information Sciences
	   Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771
  
  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.

  Seeing how at least eight drivers use this code, (not counting the
  PCMCIA ones either) it is easy to break some card by what seems like
  a simple innocent change. Please contact me or Donald if you think
  you have found something that needs changing. -- PG


  Changelog:

  Paul Gortmaker	: remove set_bit lock, other cleanups.
  Paul Gortmaker	: add ei_get_8390_hdr() so we can pass skb's to 
			  ei_block_input() for eth_io_copy_and_sum().
  Paul Gortmaker	: exchange static int ei_pingpong for a #define,
			  also add better Tx error handling.
  Paul Gortmaker	: rewrite Rx overrun handling as per NS specs.
  Alexey Kuznetsov	: use the 8390's six bit hash multicast filter.
  Paul Gortmaker	: tweak ANK's above multicast changes a bit.
  Paul Gortmaker	: update packet statistics for v2.1.x
  Alan Cox		: support arbitary stupid port mappings on the
  			  68K Macintosh. Support >16bit I/O spaces
  Paul Gortmaker	: add kmod support for auto-loading of the 8390
			  module by all drivers that require it.
  Alan Cox		: Spinlocking work, added 'BUG_83C690'

  Sources:
  The National Semiconductor LAN Databook, and the 3Com 3c503 databook.

  */

static const char *version =
    "8390.c:v1.10cvs 9/23/94 Donald Becker ([e-mail])\n";

#include <linux/module.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/uaccess.h>
#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/in.h>
#include <linux/interrupt.h>
#include <linux/init.h>

#include <linux/netdevice.h>
#include <linux/etherdevice.h>

#define NS8390_CORE
#include "8390.h"

#define BUG_83C690

/* 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.
	void get_8390_hdr(struct device *dev, struct e8390_hdr *hdr, int ring_page)
		Read the 4 byte, page aligned 8390 header. *If* there is a
		subsequent read, it will be of the rest of the packet.
	void block_input(struct device *dev, int count, struct sk_buff *skb, int ring_offset)
		Read COUNT bytes from the packet buffer into the skb data area. Start 
		reading from RING_OFFSET, the address as the 8390 sees it.  This will always
		follow the read of the 8390 header. 
*/
#define ei_reset_8390 (ei_local->reset_8390)
#define ei_block_output (ei_local->block_output)
#define ei_block_input (ei_local->block_input)
#define ei_get_8390_hdr (ei_local->get_8390_hdr)

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

/* Index to functions. */
static void ei_tx_intr(struct device *dev);
static void ei_tx_err(struct device *dev);
static void ei_receive(struct device *dev);
static void ei_rx_overrun(struct device *dev);

/* Routines generic to NS8390-based boards. */
static void NS8390_trigger_send(struct device *dev, unsigned int length,
								int start_page);
static void set_multicast_list(struct device *dev);
static void do_set_multicast_list(struct device *dev);

/*
 *	SMP and the 8390 setup.
 *
 *	The 8390 isnt exactly designed to be multithreaded on RX/TX. There is
 *	a page register that controls bank and packet buffer access. We guard
 *	this with ei_local->page_lock. Nobody should assume or set the page other
 *	than zero when the lock is not held. Lock holders must restore page 0
 *	before unlocking. Even pure readers must take the lock to protect in 
 *	page 0.
 *
 *	To make life difficult the chip can also be very slow. We therefore can't
 *	just use spinlocks. For the longer lockups we disable the irq the device
 *	sits on and hold the lock. We must hold the lock because there is a dual
 *	processor case other than interrupts (get stats/set multicast list in
 *	parallel with each other and transmit).
 *
 *	Note: in theory we can just disable the irq on the card _but_ there is
 *	a latency on SMP irq delivery. So we can easily go "disable irq" "sync irqs"
 *	enter lock, take the queued irq. So we waddle instead of flying.
 *
 *	Finally by special arrangement for the purpose of being generally 
 *	annoying the transmit function is called bh atomic. That places
 *	restrictions on the user context callers as disable_irq won't save
 *	them.
 */
 


/* 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)
{
	unsigned long flags;
	struct ei_device *ei_local = (struct ei_device *) dev->priv;

	/* This can't happen unless somebody forgot to call ethdev_init(). */
	if (ei_local == NULL) 
	{
		printk(KERN_EMERG "%s: ei_open passed a non-existent device!\n", dev->name);
		return -ENXIO;
	}
    
	/*
	 *	Grab the page lock so we own the register set, then call
	 *	the init function.
	 */
      
      	spin_lock_irqsave(&ei_local->page_lock, flags);
	NS8390_init(dev, 1);
	/* Set the flag before we drop the lock, That way the IRQ arrives
	   after its set and we get no silly warnings */
	dev->start = 1;
      	spin_unlock_irqrestore(&ei_local->page_lock, flags);
	ei_local->irqlock = 0;
	return 0;
}

/* Opposite of above. Only used when "ifconfig <devname> down" is done. */
int ei_close(struct device *dev)
{
	struct ei_device *ei_local = (struct ei_device *) dev->priv;
	unsigned long flags;

	/*
	 *	Hold the page lock during close
	 */
	 	
      	spin_lock_irqsave(&ei_local->page_lock, flags);
	NS8390_init(dev, 0);
      	spin_unlock_irqrestore(&ei_local->page_lock, flags);
	dev->start = 0;
	return 0;
}

static int ei_start_xmit(struct sk_buff *skb, struct device *dev)
{
	long e8390_base = dev->base_addr;
	struct ei_device *ei_local = (struct ei_device *) dev->priv;
	int length, send_length, output_page;
	unsigned long flags;

	/*
	 *  We normally shouldn't be called if dev->tbusy is set, but the
	 *  existing code does anyway. If it has been too long since the
	 *  last Tx, we assume the board has died and kick it. We are
	 *  bh_atomic here.
	 */
 
	if (dev->tbusy) 
	{	/* Do timeouts, just like the 8003 driver. */
		int txsr;
		int isr;
		int tickssofar = jiffies - dev->trans_start;

		/*
		 *	Need the page lock. Now see what went wrong. This bit is
		 *	fast.
		 */
		 		
		spin_lock_irqsave(&ei_local->page_lock, flags);
		txsr = inb(e8390_base+EN0_TSR);
		if (tickssofar < TX_TIMEOUT ||	(tickssofar < (TX_TIMEOUT+5) && ! (txsr & ENTSR_PTX))) 
		{
			spin_unlock_irqrestore(&ei_local->page_lock, flags);
			return 1;
		}

		ei_local->stat.tx_errors++;
		isr = inb(e8390_base+EN0_ISR);
		if (dev->start == 0) 
		{
			spin_unlock_irqrestore(&ei_local->page_lock, flags);
			printk(KERN_WARNING "%s: xmit on stopped card\n", dev->name);
			return 1;
		}

		/*
		 * Note that if the Tx posted a TX_ERR interrupt, then the
		 * error will have been handled from the interrupt handler
		 * and not here. Error statistics are handled there as well.
		 */

		printk(KERN_DEBUG "%s: Tx timed out, %s TSR=%#2x, ISR=%#2x, t=%d.\n",
			dev->name, (txsr & ENTSR_ABT) ? "excess collisions." :
			(isr) ? "lost interrupt?" : "cable problem?", txsr, isr, tickssofar);

		if (!isr && !ei_local->stat.tx_packets) 
		{
			/* The 8390 probably hasn't gotten on the cable yet. */
			ei_local->interface_num ^= 1;   /* Try a different xcvr.  */
		}

		/*
		 *	Play shuffle the locks, a reset on some chips takes a few
		 *	mS. We very rarely hit this point.
		 */
		 
		spin_unlock_irqrestore(&ei_local->page_lock, flags);

		/* Ugly but a reset can be slow, yet must be protected */
		
		disable_irq_nosync(dev->irq);
		spin_lock(&ei_local->page_lock);
		
		/* Try to restart the card.  Perhaps the user has fixed something. */
		ei_reset_8390(dev);
		NS8390_init(dev, 1);
		
		spin_unlock(&ei_local->page_lock);
		enable_irq(dev->irq);
		dev->trans_start = jiffies;
	}
    
	length = skb->len;

	/* Mask interrupts from the ethercard. 
	   SMP: We have to grab the lock here otherwise the IRQ handler
	   on another CPU can flip window and race the IRQ mask set. We end
	   up trashing the mcast filter not disabling irqs if we dont lock */
	   
	spin_lock_irqsave(&ei_local->page_lock, flags);
	outb_p(0x00, e8390_base + EN0_IMR);
	spin_unlock_irqrestore(&ei_local->page_lock, flags);
	
	
	/*
	 *	Slow phase with lock held.
	 */
	 
	disable_irq_nosync(dev->irq);
	
	spin_lock(&ei_local->page_lock);
	
	if (dev->interrupt) 
	{
		printk(KERN_WARNING "%s: Tx request while isr active.\n",dev->name);
		outb_p(ENISR_ALL, e8390_base + EN0_IMR);
		spin_unlock(&ei_local->page_lock);
		enable_irq(dev->irq);
		ei_local->stat.tx_errors++;
		dev_kfree_skb(skb);
		return 0;
	}
	ei_local->irqlock = 1;

	send_length = ETH_ZLEN < length ? length : ETH_ZLEN;
    
#ifdef EI_PINGPONG

	/*
	 * We have two Tx slots available for use. Find the first free
	 * slot, and then perform some sanity checks. With two Tx bufs,
	 * you get very close to transmitting back-to-back packets. With
	 * only one Tx buf, the transmitter sits idle while you reload the
	 * card, leaving a substantial gap between each transmitted packet.
	 */

	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(KERN_DEBUG "%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 + TX_1X_PAGES;
		ei_local->tx2 = send_length;
		if (ei_debug  &&  ei_local->tx1 > 0)
			printk(KERN_DEBUG "%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(KERN_DEBUG "%s: No Tx buffers free! irq=%ld tx1=%d tx2=%d last=%d\n",
				dev->name, dev->interrupt, ei_local->tx1, ei_local->tx2, ei_local->lasttx);
		ei_local->irqlock = 0;
		dev->tbusy = 1;
		outb_p(ENISR_ALL, e8390_base + EN0_IMR);
		spin_unlock(&ei_local->page_lock);
		enable_irq(dev->irq);
		ei_local->stat.tx_errors++;
		return 1;
	}

	/*
	 * Okay, now upload the packet and trigger a send if the transmitter
	 * isn't already sending. If it is busy, the interrupt handler will
	 * trigger the send later, upon receiving a Tx done interrupt.
	 */

	ei_block_output(dev, length, skb->data, output_page);
	if (! ei_local->txing) 
	{
		ei_local->txing = 1;
		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;
		}
	}
	else ei_local->txqueue++;

	dev->tbusy = (ei_local->tx1  &&  ei_local->tx2);

#else	/* EI_PINGPONG */

	/*
	 * Only one Tx buffer in use. You need two Tx bufs to come close to
	 * back-to-back transmits. Expect a 20 -> 25% performance hit on
	 * reasonable hardware if you only use one Tx buffer.
	 */