3c505.c

/*
 * Linux Ethernet device driver for the 3Com Etherlink Plus (3C505)
 *      By Craig Southeren, Juha Laiho and Philip Blundell
 *
 * 3c505.c      This module implements an interface to the 3Com
 *              Etherlink Plus (3c505) Ethernet card. Linux device
 *              driver interface reverse engineered from the Linux 3C509
 *              device drivers. Some 3C505 information gleaned from
 *              the Crynwr packet driver. Still this driver would not
 *              be here without 3C505 technical reference provided by
 *              3Com.
 *
 * $Id: 3c505.c,v 1.10 1996/04/16 13:06:27 phil Exp $
 *
 * Authors:     Linux 3c505 device driver by
 *                      Craig Southeren, <craigs@ineluki.apana.org.au>
 *              Final debugging by
 *                      Andrew Tridgell, <tridge@nimbus.anu.edu.au>
 *              Auto irq/address, tuning, cleanup and v1.1.4+ kernel mods by
 *                      Juha Laiho, <jlaiho@ichaos.nullnet.fi>
 *              Linux 3C509 driver by
 *                      Donald Becker, <becker@super.org>
 *			(Now at <becker@scyld.com>)
 *              Crynwr packet driver by
 *                      Krishnan Gopalan and Gregg Stefancik,
 *                      Clemson University Engineering Computer Operations.
 *                      Portions of the code have been adapted from the 3c505
 *                         driver for NCSA Telnet by Bruce Orchard and later
 *                         modified by Warren Van Houten and krus@diku.dk.
 *              3C505 technical information provided by
 *                      Terry Murphy, of 3Com Network Adapter Division
 *              Linux 1.3.0 changes by
 *                      Alan Cox <Alan.Cox@linux.org>
 *              More debugging, DMA support, currently maintained by
 *                      Philip Blundell <philb@gnu.org>
 *              Multicard/soft configurable dma channel/rev 2 hardware support
 *                      by Christopher Collins <ccollins@pcug.org.au>
 *		Ethtool support (jgarzik), 11/17/2001
 */

#define DRV_NAME	"3c505"
#define DRV_VERSION	"1.10a"


/* Theory of operation:
 *
 * The 3c505 is quite an intelligent board.  All communication with it is done
 * by means of Primary Command Blocks (PCBs); these are transferred using PIO
 * through the command register.  The card has 256k of on-board RAM, which is
 * used to buffer received packets.  It might seem at first that more buffers
 * are better, but in fact this isn't true.  From my tests, it seems that
 * more than about 10 buffers are unnecessary, and there is a noticeable
 * performance hit in having more active on the card.  So the majority of the
 * card's memory isn't, in fact, used.  Sadly, the card only has one transmit
 * buffer and, short of loading our own firmware into it (which is what some
 * drivers resort to) there's nothing we can do about this.
 *
 * We keep up to 4 "receive packet" commands active on the board at a time.
 * When a packet comes in, so long as there is a receive command active, the
 * board will send us a "packet received" PCB and then add the data for that
 * packet to the DMA queue.  If a DMA transfer is not already in progress, we
 * set one up to start uploading the data.  We have to maintain a list of
 * backlogged receive packets, because the card may decide to tell us about
 * a newly-arrived packet at any time, and we may not be able to start a DMA
 * transfer immediately (ie one may already be going on).  We can't NAK the
 * PCB, because then it would throw the packet away.
 *
 * Trying to send a PCB to the card at the wrong moment seems to have bad
 * effects.  If we send it a transmit PCB while a receive DMA is happening,
 * it will just NAK the PCB and so we will have wasted our time.  Worse, it
 * sometimes seems to interrupt the transfer.  The majority of the low-level
 * code is protected by one huge semaphore -- "busy" -- which is set whenever
 * it probably isn't safe to do anything to the card.  The receive routine
 * must gain a lock on "busy" before it can start a DMA transfer, and the
 * transmit routine must gain a lock before it sends the first PCB to the card.
 * The send_pcb() routine also has an internal semaphore to protect it against
 * being re-entered (which would be disastrous) -- this is needed because
 * several things can happen asynchronously (re-priming the receiver and
 * asking the card for statistics, for example).  send_pcb() will also refuse
 * to talk to the card at all if a DMA upload is happening.  The higher-level
 * networking code will reschedule a later retry if some part of the driver
 * is blocked.  In practice, this doesn't seem to happen very often.
 */

/* This driver may now work with revision 2.x hardware, since all the read
 * operations on the HCR have been removed (we now keep our own softcopy).
 * But I don't have an old card to test it on.
 *
 * This has had the bad effect that the autoprobe routine is now a bit
 * less friendly to other devices.  However, it was never very good.
 * before, so I doubt it will hurt anybody.
 */

/* The driver is a mess.  I took Craig's and Juha's code, and hacked it firstly
 * to make it more reliable, and secondly to add DMA mode.  Many things could
 * probably be done better; the concurrency protection is particularly awful.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/in.h>
#include <linux/ioport.h>
#include <linux/spinlock.h>
#include <linux/ethtool.h>
#include <linux/delay.h>
#include <linux/bitops.h>
#include <linux/gfp.h>

#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/dma.h>

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

#include "3c505.h"

/*********************************************************
 *
 *  define debug messages here as common strings to reduce space
 *
 *********************************************************/

#define filename __FILE__

#define timeout_msg "*** timeout at %s:%s (line %d) ***\n"
#define TIMEOUT_MSG(lineno) \
	pr_notice(timeout_msg, filename, __func__, (lineno))

#define invalid_pcb_msg "*** invalid pcb length %d at %s:%s (line %d) ***\n"
#define INVALID_PCB_MSG(len) \
	pr_notice(invalid_pcb_msg, (len), filename, __func__, __LINE__)

#define search_msg "%s: Looking for 3c505 adapter at address %#x..."

#define stilllooking_msg "still looking..."

#define found_msg "found.\n"

#define notfound_msg "not found (reason = %d)\n"

#define couldnot_msg "%s: 3c505 not found\n"

/*********************************************************
 *
 *  various other debug stuff
 *
 *********************************************************/

#ifdef ELP_DEBUG
static int elp_debug = ELP_DEBUG;
#else
static int elp_debug;
#endif
#define debug elp_debug

/*
 *  0 = no messages (well, some)
 *  1 = messages when high level commands performed
 *  2 = messages when low level commands performed
 *  3 = messages when interrupts received
 */

/*****************************************************************
 *
 * List of I/O-addresses we try to auto-sense
 * Last element MUST BE 0!
 *****************************************************************/

static int addr_list[] __initdata = {0x300, 0x280, 0x310, 0};

/* Dma Memory related stuff */

static unsigned long dma_mem_alloc(int size)
{
	int order = get_order(size);
	return __get_dma_pages(GFP_KERNEL, order);
}


/*****************************************************************
 *
 * Functions for I/O (note the inline !)
 *
 *****************************************************************/

static inline unsigned char inb_status(unsigned int base_addr)
{
	return inb(base_addr + PORT_STATUS);
}

static inline int inb_command(unsigned int base_addr)
{
	return inb(base_addr + PORT_COMMAND);
}