de600.c

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static const char *version =
	"de600.c: $Revision: 1.40 $,  Bjorn Ekwall ([e-mail])\n";
/*
 *	de600.c
 *
 *	Linux driver for the D-Link DE-600 Ethernet pocket adapter.
 *
 *	Portions (C) Copyright 1993, 1994 by Bjorn Ekwall
 *	The Author may be reached as [e-mail]
 *
 *	Based on adapter information gathered from DE600.ASM by D-Link Inc.,
 *	as included on disk C in the v.2.11 of PC/TCP from FTP Software.
 *	For DE600.asm:
 *		Portions (C) Copyright 1990 D-Link, Inc.
 *		Copyright, 1988-1992, Russell Nelson, Crynwr Software
 *
 *	Adapted to the sample network driver core for linux,
 *	written by: Donald Becker <[e-mail]>
 *	C/O Supercomputing Research Ctr., 17100 Science Dr., Bowie MD 20715
 *
 *	compile-command:
 *	"gcc -D__KERNEL__  -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer \
 *	 -m486 -c de600.c
 *
 **************************************************************/
/*
 *	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, or (at your option)
 *	any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with this program; if not, write to the Free Software
 *	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 **************************************************************/
/* Add more time here if your adapter won't work OK: */
#define DE600_SLOW_DOWN udelay(delay_time)

 /*
 * If you still have trouble reading/writing to the adapter,
 * modify the following "#define": (see <asm/io.h> for more info)
#define REALLY_SLOW_IO
 */
#define SLOW_IO_BY_JUMPING /* Looks "better" than dummy write to port 0x80 :-) */

/*
 * If you want to enable automatic continuous checking for the DE600,
 * keep this #define enabled.
 * It doesn't cost much per packet, so I think it is worth it!
 * If you disagree, comment away the #define, and live with it...
 *
 */
#define CHECK_LOST_DE600

/*
 * Enable this #define if you want the adapter to do a "ifconfig down" on
 * itself when we have detected that something is possibly wrong with it.
 * The default behaviour is to retry with "adapter_init()" until success.
 * This should be used for debugging purposes only.
 * (Depends on the CHECK_LOST_DE600 above)
 *
 */
#define SHUTDOWN_WHEN_LOST

/*
 * See comment at "de600_rspace()"!
 * This is an *ugly* hack, but for now it achieves its goal of
 * faking a TCP flow-control that will not flood the poor DE600.
 *
 * Tricks TCP to announce a small max window (max 2 fast packets please :-)
 *
 * Comment away at your own risk!
 *
 * Update: Use the more general per-device maxwindow parameter instead.
 */
#undef FAKE_SMALL_MAX

/* use 0 for production, 1 for verification, >2 for debug */
#ifdef DE600_DEBUG
#define PRINTK(x) if (de600_debug >= 2) printk x
#else
#define DE600_DEBUG 0
#define PRINTK(x) /**/
#endif

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <asm/io.h>
#include <linux/in.h>
#include <linux/ptrace.h>
#include <asm/system.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/delay.h>

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

static unsigned int de600_debug = DE600_DEBUG;
MODULE_PARM(de600_debug, "i");

static unsigned int delay_time = 10;
MODULE_PARM(delay_time, "i");

#ifdef FAKE_SMALL_MAX
static unsigned long de600_rspace(struct sock *sk);
#include <net/sock.h>
#endif

typedef unsigned char byte;

/**************************************************
 *                                                *
 * Definition of D-Link Ethernet Pocket adapter   *
 *                                                *
 **************************************************/
/*
 * D-Link Ethernet pocket adapter ports
 */
/*
 * OK, so I'm cheating, but there are an awful lot of
 * reads and writes in order to get anything in and out
 * of the DE-600 with 4 bits at a time in the parallel port,
 * so every saved instruction really helps :-)
 *
 * That is, I don't care what the device struct says
 * but hope that Space.c will keep the rest of the drivers happy.
 */
#ifndef DE600_IO
#define DE600_IO 0x378
#endif

#define DATA_PORT	(DE600_IO)
#define STATUS_PORT	(DE600_IO + 1)
#define COMMAND_PORT	(DE600_IO + 2)

#ifndef DE600_IRQ
#define DE600_IRQ	7
#endif
/*
 * It really should look like this, and autoprobing as well...
 *
#define DATA_PORT	(dev->base_addr + 0)
#define STATUS_PORT	(dev->base_addr + 1)
#define COMMAND_PORT	(dev->base_addr + 2)
#define DE600_IRQ	dev->irq
 */

/*
 * D-Link COMMAND_PORT commands
 */
#define SELECT_NIC	0x04 /* select Network Interface Card */
#define SELECT_PRN	0x1c /* select Printer */
#define NML_PRN		0xec /* normal Printer situation */
#define IRQEN		0x10 /* enable IRQ line */

/*
 * D-Link STATUS_PORT
 */
#define RX_BUSY		0x80
#define RX_GOOD		0x40
#define TX_FAILED16	0x10
#define TX_BUSY		0x08

/*
 * D-Link DATA_PORT commands
 * command in low 4 bits
 * data in high 4 bits
 * select current data nibble with HI_NIBBLE bit
 */
#define WRITE_DATA	0x00 /* write memory */
#define READ_DATA	0x01 /* read memory */
#define STATUS		0x02 /* read  status register */
#define COMMAND		0x03 /* write command register (see COMMAND below) */
#define NULL_COMMAND	0x04 /* null command */
#define RX_LEN		0x05 /* read  received packet length */
#define TX_ADDR		0x06 /* set adapter transmit memory address */
#define RW_ADDR		0x07 /* set adapter read/write memory address */
#define HI_NIBBLE	0x08 /* read/write the high nibble of data,
				or-ed with rest of command */

/*
 * command register, accessed through DATA_PORT with low bits = COMMAND
 */
#define RX_ALL		0x01 /* PROMISCUOUS */
#define RX_BP		0x02 /* default: BROADCAST & PHYSICAL ADDRESS */
#define RX_MBP		0x03 /* MULTICAST, BROADCAST & PHYSICAL ADDRESS */

#define TX_ENABLE	0x04 /* bit 2 */
#define RX_ENABLE	0x08 /* bit 3 */

#define RESET		0x80 /* set bit 7 high */
#define STOP_RESET	0x00 /* set bit 7 low */

/*
 * data to command register
 * (high 4 bits in write to DATA_PORT)
 */
#define RX_PAGE2_SELECT	0x10 /* bit 4, only 2 pages to select */
#define RX_BASE_PAGE	0x20 /* bit 5, always set when specifying RX_ADDR */
#define FLIP_IRQ	0x40 /* bit 6 */

/*
 * D-Link adapter internal memory:
 *
 * 0-2K 1:st transmit page (send from pointer up to 2K)
 * 2-4K	2:nd transmit page (send from pointer up to 4K)
 *
 * 4-6K 1:st receive page (data from 4K upwards)
 * 6-8K 2:nd receive page (data from 6K upwards)
 *
 * 8K+	Adapter ROM (contains magic code and last 3 bytes of Ethernet address)
 */
#define MEM_2K		0x0800 /* 2048 */
#define MEM_4K		0x1000 /* 4096 */
#define MEM_6K		0x1800 /* 6144 */
#define NODE_ADDRESS	0x2000 /* 8192 */

#define RUNT 60		/* Too small Ethernet packet */

/**************************************************
 *                                                *
 *             End of definition                  *
 *                                                *
 **************************************************/

/*
 * Index to functions, as function prototypes.
 */
/* Routines used internally. (See "convenience macros") */
static byte	de600_read_status(struct net_device *dev);
static byte	de600_read_byte(unsigned char type, struct net_device *dev);

/* Put in the device structure. */
static int	de600_open(struct net_device *dev);
static int	de600_close(struct net_device *dev);
static struct net_device_stats *get_stats(struct net_device *dev);
static int	de600_start_xmit(struct sk_buff *skb, struct net_device *dev);

/* Dispatch from interrupts. */
static void	de600_interrupt(int irq, void *dev_id, struct pt_regs *regs);
static int	de600_tx_intr(struct net_device *dev, int irq_status);
static void	de600_rx_intr(struct net_device *dev);

/* Initialization */
static void	trigger_interrupt(struct net_device *dev);
int		de600_probe(struct net_device *dev);
static int	adapter_init(struct net_device *dev);

/*
 * D-Link driver variables:
 */
static volatile int		rx_page		= 0;

#define TX_PAGES 2
static volatile int		tx_fifo[TX_PAGES];
static volatile int		tx_fifo_in = 0;
static volatile int		tx_fifo_out = 0;
static volatile int		free_tx_pages = TX_PAGES;
static int			was_down = 0;

/*
 * Convenience macros/functions for D-Link adapter
 */

#define select_prn() outb_p(SELECT_PRN, COMMAND_PORT); DE600_SLOW_DOWN
#define select_nic() outb_p(SELECT_NIC, COMMAND_PORT); DE600_SLOW_DOWN

/* Thanks for hints from Mark Burton <[e-mail]> */
#define de600_put_byte(data) ( \
	outb_p(((data) << 4)   | WRITE_DATA            , DATA_PORT), \
	outb_p(((data) & 0xf0) | WRITE_DATA | HI_NIBBLE, DATA_PORT))

/*
 * The first two outb_p()'s below could perhaps be deleted if there
 * would be more delay in the last two. Not certain about it yet...
 */
#define de600_put_command(cmd) ( \
	outb_p(( rx_page        << 4)   | COMMAND            , DATA_PORT), \
	outb_p(( rx_page        & 0xf0) | COMMAND | HI_NIBBLE, DATA_PORT), \
	outb_p(((rx_page | cmd) << 4)   | COMMAND            , DATA_PORT), \
	outb_p(((rx_page | cmd) & 0xf0) | COMMAND | HI_NIBBLE, DATA_PORT))

#define de600_setup_address(addr,type) ( \
	outb_p((((addr) << 4) & 0xf0) | type            , DATA_PORT), \
	outb_p(( (addr)       & 0xf0) | type | HI_NIBBLE, DATA_PORT), \
	outb_p((((addr) >> 4) & 0xf0) | type            , DATA_PORT), \
	outb_p((((addr) >> 8) & 0xf0) | type | HI_NIBBLE, DATA_PORT))

#define rx_page_adr() ((rx_page & RX_PAGE2_SELECT)?(MEM_6K):(MEM_4K))

/* Flip bit, only 2 pages */
#define next_rx_page() (rx_page ^= RX_PAGE2_SELECT)

#define tx_page_adr(a) (((a) + 1) * MEM_2K)

static inline byte
de600_read_status(struct net_device *dev)
{
	byte status;

	outb_p(STATUS, DATA_PORT);
	status = inb(STATUS_PORT);
	outb_p(NULL_COMMAND | HI_NIBBLE, DATA_PORT);

	return status;
}

static inline byte
de600_read_byte(unsigned char type, struct net_device *dev) { /* dev used by macros */
	byte lo;

	(void)outb_p((type), DATA_PORT);
	lo = ((unsigned char)inb(STATUS_PORT)) >> 4;
	(void)outb_p((type) | HI_NIBBLE, DATA_PORT);
	return ((unsigned char)inb(STATUS_PORT) & (unsigned char)0xf0) | lo;
}

/*
 * Open/initialize the board.  This is called (in the current kernel)
 * after booting when 'ifconfig <dev->name> $IP_ADDR' is run (in rc.inet1).
 *
 * This routine should set everything up anew at each open, even
 * registers that "should" only need to be set once at boot, so that
 * there is a non-reboot way to recover if something goes wrong.
 */
static int
de600_open(struct net_device *dev)
{
	int ret = request_irq(DE600_IRQ, de600_interrupt, 0, dev->name, dev);
	if (ret) {
		printk ("%s: unable to get IRQ %d\n", dev->name, DE600_IRQ);
		return ret;
	}

	if (adapter_init(dev))
		return -EIO;

	return 0;
}

/*
 * The inverse routine to de600_open().
 */
static int
de600_close(struct net_device *dev)
{
	select_nic();
	rx_page = 0;
	de600_put_command(RESET);
	de600_put_command(STOP_RESET);
	de600_put_command(0);
	select_prn();

	if (netif_running(dev)) { /* perhaps not needed? */
		free_irq(DE600_IRQ, dev);
	}
	return 0;
}

static struct net_device_stats *
get_stats(struct net_device *dev)
{
    return (struct net_device_stats *)(dev->priv);
}

static inline void
trigger_interrupt(struct net_device *dev)
{
	de600_put_command(FLIP_IRQ);
	select_prn();
	DE600_SLOW_DOWN;
	select_nic();
	de600_put_command(0);
}

/*
 * Copy a buffer to the adapter transmit page memory.
 * Start sending.
 */
static int
de600_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	unsigned long flags;
	int	transmit_from;
	int	len;
	int	tickssofar;
	byte	*buffer = skb->data;

	if (free_tx_pages <= 0) {	/* Do timeouts, to avoid hangs. */
		tickssofar = jiffies - dev->trans_start;

		if (tickssofar < 5)
			return 1;

		/* else */
		printk("%s: transmit timed out (%d), %s?\n",
			dev->name,
			tickssofar,
			"network cable problem"
			);
		/* Restart the adapter. */
		if (adapter_init(dev)) {
			return 1;
		}
	}

	/* Start real output */
	PRINTK(("de600_start_xmit:len=%d, page %d/%d\n", skb->len, tx_fifo_in, free_tx_pages));