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/* isa-skeleton.c: A network driver outline for linux.

 *

 *      Written 1993-94 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 General Public License, incorporated herein by reference.

 *

 *      The author may be reached as becker@scyld.com, or C/O

 *      Scyld Computing Corporation

 *      410 Severn Ave., Suite 210

 *      Annapolis MD 21403

 *

 *      This file is an outline for writing a network device driver for the

 *      the Linux operating system.

 *

 *      To write (or understand) a driver, have a look at the "loopback.c" file to

 *      get a feel of what is going on, and then use the code below as a skeleton

 *      for the new driver.

 *

 */

static const char *version =

        "isa-skeleton.c:v1.51 9/24/94 Donald Becker (becker@cesdis.gsfc.nasa.gov)\n";

/*

 *  Sources:

 *      List your sources of programming information to document that

 *      the driver is your own creation, and give due credit to others

 *      that contributed to the work. Remember that GNU project code

 *      cannot use proprietary or trade secret information. Interface

 *      definitions are generally considered non-copyrightable to the

 *      extent that the same names and structures must be used to be

 *      compatible.

 *

 *      Finally, keep in mind that the Linux kernel is has an API, not

 *      ABI. Proprietary object-code-only distributions are not permitted

 *      under the GPL.

 */

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/types.h>

#include <linux/fcntl.h>

#include <linux/interrupt.h>

#include <linux/ioport.h>

#include <linux/in.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/spinlock.h>

#include <linux/errno.h>

#include <linux/init.h>

#include <linux/netdevice.h>

#include <linux/etherdevice.h>

#include <linux/skbuff.h>

#include <linux/bitops.h>

#include <asm/system.h>

#include <asm/io.h>

#include <asm/dma.h>

/*

 * The name of the card. Is used for messages and in the requests for

 * io regions, irqs and dma channels

 */

static const char* cardname = "netcard";

/* First, a few definitions that the brave might change. */

/* A zero-terminated list of I/O addresses to be probed. */

static unsigned int netcard_portlist[] __initdata =

   { 0x200, 0x240, 0x280, 0x2C0, 0x300, 0x320, 0x340, 0};

/* use 0 for production, 1 for verification, >2 for debug */

#ifndef NET_DEBUG

#define NET_DEBUG 2

#endif

static unsigned int net_debug = NET_DEBUG;

/* The number of low I/O ports used by the ethercard. */

#define NETCARD_IO_EXTENT       32

#define MY_TX_TIMEOUT  ((400*HZ)/1000)

/* Information that need to be kept for each board. */

struct net_local {

        struct net_device_stats stats;

        long open_time;                 /* Useless example local info. */

        /* Tx control lock.  This protects the transmit buffer ring

         * state along with the "tx full" state of the driver.  This

         * means all netif_queue flow control actions are protected

         * by this lock as well.

         */

        spinlock_t lock;

};

/* The station (ethernet) address prefix, used for IDing the board. */

#define SA_ADDR0 0x00

#define SA_ADDR1 0x42

#define SA_ADDR2 0x65

/* Index to functions, as function prototypes. */

static int      netcard_probe1(struct net_device *dev, int ioaddr);

static int      net_open(struct net_device *dev);

static int      net_send_packet(struct sk_buff *skb, struct net_device *dev);

static irqreturn_t net_interrupt(int irq, void *dev_id);

static void     net_rx(struct net_device *dev);

static int      net_close(struct net_device *dev);

static struct   net_device_stats *net_get_stats(struct net_device *dev);

static void     set_multicast_list(struct net_device *dev);

static void     net_tx_timeout(struct net_device *dev);

/* Example routines you must write ;->. */

#define tx_done(dev) 1

static void     hardware_send_packet(short ioaddr, char *buf, int length);

static void     chipset_init(struct net_device *dev, int startp);

/*

 * Check for a network adaptor of this type, and return '0' iff one exists.

 * If dev->base_addr == 0, probe all likely locations.

 * If dev->base_addr == 1, always return failure.

 * If dev->base_addr == 2, allocate space for the device and return success

 * (detachable devices only).

 */

static int __init do_netcard_probe(struct net_device *dev)

{

        int i;

        int base_addr = dev->base_addr;

        int irq = dev->irq;

        if (base_addr > 0x1ff)    /* Check a single specified location. */

                return netcard_probe1(dev, base_addr);

        else if (base_addr != 0)  /* Don't probe at all. */

                return -ENXIO;

        for (i = 0; netcard_portlist[i]; i++) {

                int ioaddr = netcard_portlist[i];

                if (netcard_probe1(dev, ioaddr) == 0)

                        return 0;

                dev->irq = irq;

        }

        return -ENODEV;

}

static void cleanup_card(struct net_device *dev)

{

#ifdef jumpered_dma

        free_dma(dev->dma);

#endif

#ifdef jumpered_interrupts

        free_irq(dev->irq, dev);

#endif

        release_region(dev->base_addr, NETCARD_IO_EXTENT);

}

#ifndef MODULE

struct net_device * __init netcard_probe(int unit)

{

        struct net_device *dev = alloc_etherdev(sizeof(struct net_local));

        int err;

        if (!dev)

                return ERR_PTR(-ENOMEM);

        sprintf(dev->name, "eth%d", unit);

        netdev_boot_setup_check(dev);

        err = do_netcard_probe(dev);

        if (err)

                goto out;

        return dev;

out:

        free_netdev(dev);

        return ERR_PTR(err);

}

#endif

/*

 * This is the real probe routine. Linux has a history of friendly device

 * probes on the ISA bus. A good device probes avoids doing writes, and

 * verifies that the correct device exists and functions.

 */

static int __init netcard_probe1(struct net_device *dev, int ioaddr)

{

        struct net_local *np;

        static unsigned version_printed;

        int i;

        int err = -ENODEV;

        DECLARE_MAC_BUF(mac);

        /* Grab the region so that no one else tries to probe our ioports. */

        if (!request_region(ioaddr, NETCARD_IO_EXTENT, cardname))

                return -EBUSY;

        /*

         * For ethernet adaptors the first three octets of the station address

         * contains the manufacturer's unique code. That might be a good probe

         * method. Ideally you would add additional checks.

         */

        if (inb(ioaddr + 0) != SA_ADDR0

                ||       inb(ioaddr + 1) != SA_ADDR1

                ||       inb(ioaddr + 2) != SA_ADDR2)

                goto out;

        if (net_debug  &&  version_printed++ == 0)

                printk(KERN_DEBUG "%s", version);

        printk(KERN_INFO "%s: %s found at %#3x, ", dev->name, cardname, ioaddr);

        /* Fill in the 'dev' fields. */

        dev->base_addr = ioaddr;

        /* Retrieve and print the ethernet address. */

        for (i = 0; i < 6; i++)

                dev->dev_addr[i] = inb(ioaddr + i);

        printk("%s", print_mac(mac, dev->dev_addr));

        err = -EAGAIN;

#ifdef jumpered_interrupts

        /*

         * If this board has jumpered interrupts, allocate the interrupt

         * vector now. There is no point in waiting since no other device

         * can use the interrupt, and this marks the irq as busy. Jumpered

         * interrupts are typically not reported by the boards, and we must

         * used autoIRQ to find them.

         */

        if (dev->irq == -1)

                ;       /* Do nothing: a user-level program will set it. */

        else if (dev->irq < 2) {        /* "Auto-IRQ" */

                unsigned long irq_mask = probe_irq_on();

                /* Trigger an interrupt here. */

                dev->irq = probe_irq_off(irq_mask);

                if (net_debug >= 2)

                        printk(" autoirq is %d", dev->irq);

        } else if (dev->irq == 2)

                /*

                 * Fixup for users that don't know that IRQ 2 is really

                 * IRQ9, or don't know which one to set.

                 */

                dev->irq = 9;

        {

                int irqval = request_irq(dev->irq, &net_interrupt, 0, cardname, dev);

                if (irqval) {

                        printk("%s: unable to get IRQ %d (irqval=%d).\n",

                                   dev->name, dev->irq, irqval);

                        goto out;

                }

        }

#endif  /* jumpered interrupt */

#ifdef jumpered_dma

        /*

         * If we use a jumpered DMA channel, that should be probed for and

         * allocated here as well. See lance.c for an example.

         */

        if (dev->dma == 0) {

                if (request_dma(dev->dma, cardname)) {

                        printk("DMA %d allocation failed.\n", dev->dma);

                        goto out1;

                } else

                        printk(", assigned DMA %d.\n", dev->dma);

        } else {

                short dma_status, new_dma_status;

                /* Read the DMA channel status registers. */

                dma_status = ((inb(DMA1_STAT_REG) >> 4) & 0x0f) |

                        (inb(DMA2_STAT_REG) & 0xf0);

                /* Trigger a DMA request, perhaps pause a bit. */

                outw(0x1234, ioaddr + 8);

                /* Re-read the DMA status registers. */

                new_dma_status = ((inb(DMA1_STAT_REG) >> 4) & 0x0f) |

                        (inb(DMA2_STAT_REG) & 0xf0);

                /*

                 * Eliminate the old and floating requests,

                 * and DMA4 the cascade.

                 */

                new_dma_status ^= dma_status;

                new_dma_status &= ~0x10;

                for (i = 7; i > 0; i--)

                        if (test_bit(i, &new_dma_status)) {

                                dev->dma = i;

                                break;

                        }

                if (i <= 0) {

                        printk("DMA probe failed.\n");

                        goto out1;

                }

                if (request_dma(dev->dma, cardname)) {

                        printk("probed DMA %d allocation failed.\n", dev->dma);

                        goto out1;

                }

        }

#endif  /* jumpered DMA */

        np = netdev_priv(dev);

        spin_lock_init(&np->lock);

        dev->open               = net_open;

        dev->stop               = net_close;

        dev->hard_start_xmit    = net_send_packet;

        dev->get_stats          = net_get_stats;

        dev->set_multicast_list = &set_multicast_list;

        dev->tx_timeout         = &net_tx_timeout;

        dev->watchdog_timeo     = MY_TX_TIMEOUT;

        err = register_netdev(dev);

        if (err)

                goto out2;

        return 0;

out2:

#ifdef jumpered_dma

        free_dma(dev->dma);

#endif

out1:

#ifdef jumpered_interrupts

        free_irq(dev->irq, dev);

#endif

out:

        release_region(base_addr, NETCARD_IO_EXTENT);

        return err;

}

static void net_tx_timeout(struct net_device *dev)

{

        struct net_local *np = netdev_priv(dev);

        printk(KERN_WARNING "%s: transmit timed out, %s?\n", dev->name,

               tx_done(dev) ? "IRQ conflict" : "network cable problem");

        /* Try to restart the adaptor. */

        chipset_init(dev, 1);

        np->stats.tx_errors++;

        /* If we have space available to accept new transmit

         * requests, wake up the queueing layer.  This would

         * be the case if the chipset_init() call above just

         * flushes out the tx queue and empties it.

         *

         * If instead, the tx queue is retained then the

         * netif_wake_queue() call should be placed in the

         * TX completion interrupt handler of the driver instead

         * of here.

         */

        if (!tx_full(dev))

                netif_wake_queue(dev);

}

/*

 * Open/initialize the board. This is called (in the current kernel)

 * sometime after booting when the 'ifconfig' program is run.

 *

 * 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 non-reboot way to recover if something goes wrong.

 */

static int

net_open(struct net_device *dev)

{

        struct net_local *np = netdev_priv(dev);

        int ioaddr = dev->base_addr;

        /*

         * This is used if the interrupt line can turned off (shared).

         * See 3c503.c for an example of selecting the IRQ at config-time.

         */

        if (request_irq(dev->irq, &net_interrupt, 0, cardname, dev)) {

                return -EAGAIN;

        }

        /*

         * Always allocate the DMA channel after the IRQ,

         * and clean up on failure.

         */

        if (request_dma(dev->dma, cardname)) {

                free_irq(dev->irq, dev);

                return -EAGAIN;

        }

        /* Reset the hardware here. Don't forget to set the station address. */

        chipset_init(dev, 1);

        outb(0x00, ioaddr);

        np->open_time = jiffies;

        /* We are now ready to accept transmit requeusts from

         * the queueing layer of the networking.

         */

        netif_start_queue(dev);

        return 0;

}

/* This will only be invoked if your driver is _not_ in XOFF state.

 * What this means is that you need not check it, and that this

 * invariant will hold if you make sure that the netif_*_queue()

 * calls are done at the proper times.

 */

static int net_send_packet(struct sk_buff *skb, struct net_device *dev)

{

        struct net_local *np = netdev_priv(dev);

        int ioaddr = dev->base_addr;

        short length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;

        unsigned char *buf = skb->data;

        /* If some error occurs while trying to transmit this

         * packet, you should return '1' from this function.

         * In such a case you _may not_ do anything to the

         * SKB, it is still owned by the network queueing

         * layer when an error is returned.  This means you

         * may not modify any SKB fields, you may not free

         * the SKB, etc.

         */

#if TX_RING

        /* This is the most common case for modern hardware.

         * The spinlock protects this code from the TX complete

         * hardware interrupt handler.  Queue flow control is

         * thus managed under this lock as well.

         */

        spin_lock_irq(&np->lock);

        add_to_tx_ring(np, skb, length);

        dev->trans_start = jiffies;

        /* If we just used up the very last entry in the

         * TX ring on this device, tell the queueing

         * layer to send no more.

         */

        if (tx_full(dev))

                netif_stop_queue(dev);

        /* When the TX completion hw interrupt arrives, this

         * is when the transmit statistics are updated.

         */

        spin_unlock_irq(&np->lock);

#else

        /* This is the case for older hardware which takes

         * a single transmit buffer at a time, and it is

         * just written to the device via PIO.

         *

         * No spin locking is needed since there is no TX complete

         * event.  If by chance your card does have a TX complete

         * hardware IRQ then you may need to utilize np->lock here.

         */

        hardware_send_packet(ioaddr, buf, length);

        np->stats.tx_bytes += skb->len;

        dev->trans_start = jiffies;

        /* You might need to clean up and record Tx statistics here. */

        if (inw(ioaddr) == /*RU*/81)

                np->stats.tx_aborted_errors++;

        dev_kfree_skb (skb);

#endif

        return 0;

}

#if TX_RING

/* This handles TX complete events posted by the device

 * via interrupts.

 */

void net_tx(struct net_device *dev)

{

        struct net_local *np = netdev_priv(dev);

        int entry;

        /* This protects us from concurrent execution of

         * our dev->hard_start_xmit function above.

         */

        spin_lock(&np->lock);

        entry = np->tx_old;

        while (tx_entry_is_sent(np, entry)) {

                struct sk_buff *skb = np->skbs[entry];

                np->stats.tx_bytes += skb->len;

                dev_kfree_skb_irq (skb);

                entry = next_tx_entry(np, entry);

        }

        np->tx_old = entry;

        /* If we had stopped the queue due to a "tx full"

         * condition, and space has now been made available,

         * wake up the queue.

         */

        if (netif_queue_stopped(dev) && ! tx_full(dev))

                netif_wake_queue(dev);

        spin_unlock(&np->lock);

}

#endif

/*

 * The typical workload of the driver:

 * Handle the network interface interrupts.

 */

static irqreturn_t net_interrupt(int irq, void *dev_id)

{

        struct net_device *dev = dev_id;

        struct net_local *np;

        int ioaddr, status;

        int handled = 0;

        ioaddr = dev->base_addr;

        np = netdev_priv(dev);

        status = inw(ioaddr + 0);

        if (status == 0)

                goto out;

        handled = 1;

        if (status & RX_INTR) {

                /* Got a packet(s). */

                net_rx(dev);

        }

#if TX_RING

        if (status & TX_INTR) {

                /* Transmit complete. */

                net_tx(dev);

                np->stats.tx_packets++;

                netif_wake_queue(dev);

        }

#endif

        if (status & COUNTERS_INTR) {

                /* Increment the appropriate 'localstats' field. */

                np->stats.tx_window_errors++;

        }

out:

        return IRQ_RETVAL(handled);

}

/* We have a good packet(s), get it/them out of the buffers. */

static void

net_rx(struct net_device *dev)

{

        struct net_local *lp = netdev_priv(dev);

        int ioaddr = dev->base_addr;

        int boguscount = 10;

        do {

                int status = inw(ioaddr);

                int pkt_len = inw(ioaddr);

                if (pkt_len == 0)                /* Read all the frames? */

                        break;                  /* Done for now */

                if (status & 0x40) {    /* There was an error. */

                        lp->stats.rx_errors++;

                        if (status & 0x20) lp->stats.rx_frame_errors++;

                        if (status & 0x10) lp->stats.rx_over_errors++;

                        if (status & 0x08) lp->stats.rx_crc_errors++;

                        if (status & 0x04) lp->stats.rx_fifo_errors++;

                } else {

                        /* Malloc up new buffer. */

                        struct sk_buff *skb;

                        lp->stats.rx_bytes+=pkt_len;

                        skb = dev_alloc_skb(pkt_len);

                        if (skb == NULL) {

                                printk(KERN_NOTICE "%s: Memory squeeze, dropping packet.\n",

                                           dev->name);

                                lp->stats.rx_dropped++;

                                break;

                        }

                        skb->dev = dev;

                        /* 'skb->data' points to the start of sk_buff data area. */

                        memcpy(skb_put(skb,pkt_len), (void*)dev->rmem_start,

                                   pkt_len);

                        /* or */

                        insw(ioaddr, skb->data, (pkt_len + 1) >> 1);

                        netif_rx(skb);

                        dev->last_rx = jiffies;

                        lp->stats.rx_packets++;

                        lp->stats.rx_bytes += pkt_len;

                }

        } while (--boguscount);

        return;

}

/* The inverse routine to net_open(). */

static int

net_close(struct net_device *dev)

{

        struct net_local *lp = netdev_priv(dev);

        int ioaddr = dev->base_addr;

        lp->open_time = 0;

        netif_stop_queue(dev);

        /* Flush the Tx and disable Rx here. */

        disable_dma(dev->dma);

        /* If not IRQ or DMA jumpered, free up the line. */

        outw(0x00, ioaddr+0);    /* Release the physical interrupt line. */

        free_irq(dev->irq, dev);

        free_dma(dev->dma);

        /* Update the statistics here. */

        return 0;

}

/*

 * Get the current statistics.

 * This may be called with the card open or closed.

 */

static struct net_device_stats *net_get_stats(struct net_device *dev)

{

        struct net_local *lp = netdev_priv(dev);

        short ioaddr = dev->base_addr;

        /* Update the statistics from the device registers. */

        lp->stats.rx_missed_errors = inw(ioaddr+1);

        return &lp->stats;

}

/*

 * Set or clear the multicast filter for this adaptor.

 * num_addrs == -1      Promiscuous mode, receive all packets

 * num_addrs == 0       Normal mode, clear multicast list

 * num_addrs > 0        Multicast mode, receive normal and MC packets,

 *                      and do best-effort filtering.

 */

static void

set_multicast_list(struct net_device *dev)

{

        short ioaddr = dev->base_addr;

        if (dev->flags&IFF_PROMISC)

        {

                /* Enable promiscuous mode */

                outw(MULTICAST|PROMISC, ioaddr);

        }

        else if((dev->flags&IFF_ALLMULTI) || dev->mc_count > HW_MAX_ADDRS)

        {

                /* Disable promiscuous mode, use normal mode. */

                hardware_set_filter(NULL);

                outw(MULTICAST, ioaddr);

        }

        else if(dev->mc_count)

        {

                /* Walk the address list, and load the filter */

                hardware_set_filter(dev->mc_list);

                outw(MULTICAST, ioaddr);

        }

        else

                outw(0, ioaddr);

}

#ifdef MODULE

static struct net_device *this_device;

static int io = 0x300;

static int irq;

static int dma;

static int mem;

MODULE_LICENSE("GPL");

int init_module(void)

{

        struct net_device *dev;

        int result;

        if (io == 0)

                printk(KERN_WARNING "%s: You shouldn't use auto-probing with insmod!\n",

                           cardname);

        dev = alloc_etherdev(sizeof(struct net_local));

        if (!dev)

                return -ENOMEM;

        /* Copy the parameters from insmod into the device structure. */

        dev->base_addr = io;

        dev->irq       = irq;

        dev->dma       = dma;

        dev->mem_start = mem;

        if (do_netcard_probe(dev) == 0) {

                this_device = dev;

                return 0;

        }

        free_netdev(dev);

        return -ENXIO;

}

void

cleanup_module(void)

{

        unregister_netdev(this_device);

        cleanup_card(this_device);

        free_netdev(this_device);

}