cosa.c

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/* $Id: cosa.c,v 1.31 2000/03/08 17:47:16 kas Exp $ */

/*
 *  Copyright (C) 1995-1997  Jan "Yenya" Kasprzak <[email protected]>
 *  Generic HDLC port Copyright (C) 2008 Krzysztof Halasa <[email protected]>
 *
 *  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 of the License, 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.
 */

/*
 * The driver for the SRP and COSA synchronous serial cards.
 *
 * HARDWARE INFO
 *
 * Both cards are developed at the Institute of Computer Science,
 * Masaryk University (http://www.ics.muni.cz/). The hardware is
 * developed by Jiri Novotny <[email protected]>. More information
 * and the photo of both cards is available at
 * http://www.pavoucek.cz/cosa.html. The card documentation, firmwares
 * and other goods can be downloaded from ftp://ftp.ics.muni.cz/pub/cosa/.
 * For Linux-specific utilities, see below in the "Software info" section.
 * If you want to order the card, contact Jiri Novotny.
 *
 * The SRP (serial port?, the Czech word "srp" means "sickle") card
 * is a 2-port intelligent (with its own 8-bit CPU) synchronous serial card
 * with V.24 interfaces up to 80kb/s each.
 *
 * The COSA (communication serial adapter?, the Czech word "kosa" means
 * "scythe") is a next-generation sync/async board with two interfaces
 * - currently any of V.24, X.21, V.35 and V.36 can be selected.
 * It has a 16-bit SAB80166 CPU and can do up to 10 Mb/s per channel.
 * The 8-channels version is in development.
 *
 * Both types have downloadable firmware and communicate via ISA DMA.
 * COSA can be also a bus-mastering device.
 *
 * SOFTWARE INFO
 *
 * The homepage of the Linux driver is at http://www.fi.muni.cz/~kas/cosa/.
 * The CVS tree of Linux driver can be viewed there, as well as the
 * firmware binaries and user-space utilities for downloading the firmware
 * into the card and setting up the card.
 *
 * The Linux driver (unlike the present *BSD drivers :-) can work even
 * for the COSA and SRP in one computer and allows each channel to work
 * in one of the two modes (character or network device).
 *
 * AUTHOR
 *
 * The Linux driver was written by Jan "Yenya" Kasprzak <[email protected]>.
 *
 * You can mail me bugfixes and even success reports. I am especially
 * interested in the SMP and/or muliti-channel success/failure reports
 * (I wonder if I did the locking properly :-).
 *
 * THE AUTHOR USED THE FOLLOWING SOURCES WHEN PROGRAMMING THE DRIVER
 *
 * The COSA/SRP NetBSD driver by Zdenek Salvet and Ivos Cernohlavek
 * The skeleton.c by Donald Becker
 * The SDL Riscom/N2 driver by Mike Natale
 * The Comtrol Hostess SV11 driver by Alan Cox
 * The Sync PPP/Cisco HDLC layer (syncppp.c) ported to Linux by Alan Cox
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/hdlc.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/netdevice.h>
#include <linux/spinlock.h>
#include <linux/mutex.h>
#include <linux/device.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/byteorder.h>

#undef COSA_SLOW_IO /* for testing purposes only */

#include "cosa.h"

/* Maximum length of the identification string. */
#define COSA_MAX_ID_STRING  128

/* Maximum length of the channel name */
#define COSA_MAX_NAME       (sizeof("cosaXXXcXXX")+1)

/* Per-channel data structure */

struct channel_data {
    int usage;  /* Usage count; >0 for chrdev, -1 for netdev */
    int num;    /* Number of the channel */
    struct cosa_data *cosa; /* Pointer to the per-card structure */
    int txsize; /* Size of transmitted data */
    char *txbuf;    /* Transmit buffer */
    char name[COSA_MAX_NAME];   /* channel name */

    /* The HW layer interface */
    /* routine called from the RX interrupt */
    char *(*setup_rx)(struct channel_data *channel, int size);
    /* routine called when the RX is done (from the EOT interrupt) */
    int (*rx_done)(struct channel_data *channel);
    /* routine called when the TX is done (from the EOT interrupt) */
    int (*tx_done)(struct channel_data *channel, int size);

    /* Character device parts */
    struct mutex rlock;
    struct semaphore wsem;
    char *rxdata;
    int rxsize;
    wait_queue_head_t txwaitq, rxwaitq;
    int tx_status, rx_status;

    /* generic HDLC device parts */
    struct net_device *netdev;
    struct sk_buff *rx_skb, *tx_skb;
};

/* cosa->firmware_status bits */
#define COSA_FW_RESET       (1<<0)  /* Is the ROM monitor active? */
#define COSA_FW_DOWNLOAD    (1<<1)  /* Is the microcode downloaded? */
#define COSA_FW_START       (1<<2)  /* Is the microcode running? */

struct cosa_data {
    int num;            /* Card number */
    char name[COSA_MAX_NAME];   /* Card name - e.g "cosa0" */
    unsigned int datareg, statusreg;    /* I/O ports */
    unsigned short irq, dma;    /* IRQ and DMA number */
    unsigned short startaddr;   /* Firmware start address */
    unsigned short busmaster;   /* Use busmastering? */
    int nchannels;          /* # of channels on this card */
    int driver_status;      /* For communicating with firmware */
    int firmware_status;        /* Downloaded, reseted, etc. */
    unsigned long rxbitmap, txbitmap;/* Bitmap of channels who are willing to send/receive data */
    unsigned long rxtx;     /* RX or TX in progress? */
    int enabled;
    int usage;              /* usage count */
    int txchan, txsize, rxsize;
    struct channel_data *rxchan;
    char *bouncebuf;
    char *txbuf, *rxbuf;
    struct channel_data *chan;
    spinlock_t lock;    /* For exclusive operations on this structure */
    char id_string[COSA_MAX_ID_STRING]; /* ROM monitor ID string */
    char *type;             /* card type */
};

/*
 * Define this if you want all the possible ports to be autoprobed.
 * It is here but it probably is not a good idea to use this.
 */
/* #define COSA_ISA_AUTOPROBE   1 */

/*
 * Character device major number. 117 was allocated for us.
 * The value of 0 means to allocate a first free one.
 */
static DEFINE_MUTEX(cosa_chardev_mutex);
static int cosa_major = 117;

/*
 * Encoding of the minor numbers:
 * The lowest CARD_MINOR_BITS bits means the channel on the single card,
 * the highest bits means the card number.
 */
#define CARD_MINOR_BITS 4   /* How many bits in minor number are reserved
                 * for the single card */
/*
 * The following depends on CARD_MINOR_BITS. Unfortunately, the "MODULE_STRING"
 * macro doesn't like anything other than the raw number as an argument :-(
 */
#define MAX_CARDS   16
/* #define MAX_CARDS    (1 << (8-CARD_MINOR_BITS)) */

#define DRIVER_RX_READY     0x0001
#define DRIVER_TX_READY     0x0002
#define DRIVER_TXMAP_SHIFT  2
#define DRIVER_TXMAP_MASK   0x0c    /* FIXME: 0xfc for 8-channel version */

/*
 * for cosa->rxtx - indicates whether either transmit or receive is
 * in progress. These values are mean number of the bit.
 */
#define TXBIT 0
#define RXBIT 1
#define IRQBIT 2

#define COSA_MTU 2000   /* FIXME: I don't know this exactly */

#undef DEBUG_DATA //1   /* Dump the data read or written to the channel */
#undef DEBUG_IRQS //1   /* Print the message when the IRQ is received */
#undef DEBUG_IO   //1   /* Dump the I/O traffic */

#define TX_TIMEOUT  (5*HZ)

/* Maybe the following should be allocated dynamically */
static struct cosa_data cosa_cards[MAX_CARDS];
static int nr_cards;

#ifdef COSA_ISA_AUTOPROBE
static int io[MAX_CARDS+1]  = { 0x220, 0x228, 0x210, 0x218, 0, };
/* NOTE: DMA is not autoprobed!!! */
static int dma[MAX_CARDS+1] = { 1, 7, 1, 7, 1, 7, 1, 7, 0, };
#else
static int io[MAX_CARDS+1];
static int dma[MAX_CARDS+1];
#endif
/* IRQ can be safely autoprobed */
static int irq[MAX_CARDS+1] = { -1, -1, -1, -1, -1, -1, 0, };

/* for class stuff*/
static struct class *cosa_class;

#ifdef MODULE
module_param_array(io, int, NULL, 0);
MODULE_PARM_DESC(io, "The I/O bases of the COSA or SRP cards");
module_param_array(irq, int, NULL, 0);
MODULE_PARM_DESC(irq, "The IRQ lines of the COSA or SRP cards");
module_param_array(dma, int, NULL, 0);
MODULE_PARM_DESC(dma, "The DMA channels of the COSA or SRP cards");

MODULE_AUTHOR("Jan \"Yenya\" Kasprzak, <[email protected]>");
MODULE_DESCRIPTION("Modular driver for the COSA or SRP synchronous card");
MODULE_LICENSE("GPL");
#endif

/* I use this mainly for testing purposes */
#ifdef COSA_SLOW_IO
#define cosa_outb outb_p
#define cosa_outw outw_p
#define cosa_inb  inb_p
#define cosa_inw  inw_p
#else
#define cosa_outb outb
#define cosa_outw outw
#define cosa_inb  inb
#define cosa_inw  inw
#endif

#define is_8bit(cosa)       (!(cosa->datareg & 0x08))

#define cosa_getstatus(cosa)    (cosa_inb(cosa->statusreg))
#define cosa_putstatus(cosa, stat)  (cosa_outb(stat, cosa->statusreg))
#define cosa_getdata16(cosa)    (cosa_inw(cosa->datareg))
#define cosa_getdata8(cosa) (cosa_inb(cosa->datareg))
#define cosa_putdata16(cosa, dt)    (cosa_outw(dt, cosa->datareg))
#define cosa_putdata8(cosa, dt) (cosa_outb(dt, cosa->datareg))

/* Initialization stuff */
static int cosa_probe(int ioaddr, int irq, int dma);

/* HW interface */
static void cosa_enable_rx(struct channel_data *chan);
static void cosa_disable_rx(struct channel_data *chan);
static int cosa_start_tx(struct channel_data *channel, char *buf, int size);
static void cosa_kick(struct cosa_data *cosa);
static int cosa_dma_able(struct channel_data *chan, char *buf, int data);

/* Network device stuff */
static int cosa_net_attach(struct net_device *dev, unsigned short encoding,
               unsigned short parity);
static int cosa_net_open(struct net_device *d);
static int cosa_net_close(struct net_device *d);
static void cosa_net_timeout(struct net_device *d);
static netdev_tx_t cosa_net_tx(struct sk_buff *skb, struct net_device *d);
static char *cosa_net_setup_rx(struct channel_data *channel, int size);
static int cosa_net_rx_done(struct channel_data *channel);
static int cosa_net_tx_done(struct channel_data *channel, int size);
static int cosa_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);

/* Character device */
static char *chrdev_setup_rx(struct channel_data *channel, int size);
static int chrdev_rx_done(struct channel_data *channel);
static int chrdev_tx_done(struct channel_data *channel, int size);
static ssize_t cosa_read(struct file *file,
    char __user *buf, size_t count, loff_t *ppos);
static ssize_t cosa_write(struct file *file,
    const char __user *buf, size_t count, loff_t *ppos);
static unsigned int cosa_poll(struct file *file, poll_table *poll);
static int cosa_open(struct inode *inode, struct file *file);
static int cosa_release(struct inode *inode, struct file *file);
static long cosa_chardev_ioctl(struct file *file, unsigned int cmd,
                unsigned long arg);
#ifdef COSA_FASYNC_WORKING
static int cosa_fasync(struct inode *inode, struct file *file, int on);
#endif

static const struct file_operations cosa_fops = {
    .owner      = THIS_MODULE,
    .llseek     = no_llseek,
    .read       = cosa_read,
    .write      = cosa_write,
    .poll       = cosa_poll,
    .unlocked_ioctl = cosa_chardev_ioctl,
    .open       = cosa_open,
    .release    = cosa_release,
#ifdef COSA_FASYNC_WORKING
    .fasync     = cosa_fasync,
#endif
};

/* Ioctls */
static int cosa_start(struct cosa_data *cosa, int address);
static int cosa_reset(struct cosa_data *cosa);
static int cosa_download(struct cosa_data *cosa, void __user *a);
static int cosa_readmem(struct cosa_data *cosa, void __user *a);

/* COSA/SRP ROM monitor */
static int download(struct cosa_data *cosa, const char __user *data, int addr, int len);
static int startmicrocode(struct cosa_data *cosa, int address);
static int readmem(struct cosa_data *cosa, char __user *data, int addr, int len);
static int cosa_reset_and_read_id(struct cosa_data *cosa, char *id);

/* Auxiliary functions */
static int get_wait_data(struct cosa_data *cosa);
static int put_wait_data(struct cosa_data *cosa, int data);
static int puthexnumber(struct cosa_data *cosa, int number);
static void put_driver_status(struct cosa_data *cosa);
static void put_driver_status_nolock(struct cosa_data *cosa);

/* Interrupt handling */
static irqreturn_t cosa_interrupt(int irq, void *cosa);

/* I/O ops debugging */
#ifdef DEBUG_IO
static void debug_data_in(struct cosa_data *cosa, int data);
static void debug_data_out(struct cosa_data *cosa, int data);
static void debug_data_cmd(struct cosa_data *cosa, int data);
static void debug_status_in(struct cosa_data *cosa, int status);
static void debug_status_out(struct cosa_data *cosa, int status);
#endif

static inline struct channel_data* dev_to_chan(struct net_device *dev)
{
    return (struct channel_data *)dev_to_hdlc(dev)->priv;
}

/* ---------- Initialization stuff ---------- */

static int __init cosa_init(void)
{
    int i, err = 0;

    if (cosa_major > 0) {
        if (register_chrdev(cosa_major, "cosa", &cosa_fops)) {
            pr_warn("unable to get major %d\n", cosa_major);
            err = -EIO;
            goto out;
        }
    } else {
        if (!(cosa_major=register_chrdev(0, "cosa", &cosa_fops))) {
            pr_warn("unable to register chardev\n");
            err = -EIO;
            goto out;
        }
    }
    for (i=0; i<MAX_CARDS; i++)
        cosa_cards[i].num = -1;
    for (i=0; io[i] != 0 && i < MAX_CARDS; i++)
        cosa_probe(io[i], irq[i], dma[i]);
    if (!nr_cards) {
        pr_warn("no devices found\n");
        unregister_chrdev(cosa_major, "cosa");
        err = -ENODEV;
        goto out;
    }
    cosa_class = class_create(THIS_MODULE, "cosa");
    if (IS_ERR(cosa_class)) {
        err = PTR_ERR(cosa_class);
        goto out_chrdev;
    }
    for (i = 0; i < nr_cards; i++)
        device_create(cosa_class, NULL, MKDEV(cosa_major, i), NULL,
                  "cosa%d", i);
    err = 0;
    goto out;

out_chrdev:
    unregister_chrdev(cosa_major, "cosa");
out:
    return err;
}
module_init(cosa_init);

static void __exit cosa_exit(void)
{
    struct cosa_data *cosa;
    int i;

    for (i = 0; i < nr_cards; i++)
        device_destroy(cosa_class, MKDEV(cosa_major, i));
    class_destroy(cosa_class);

    for (cosa = cosa_cards; nr_cards--; cosa++) {
        /* Clean up the per-channel data */
        for (i = 0; i < cosa->nchannels; i++) {
            /* Chardev driver has no alloc'd per-channel data */
            unregister_hdlc_device(cosa->chan[i].netdev);
            free_netdev(cosa->chan[i].netdev);
        }
        /* Clean up the per-card data */
        kfree(cosa->chan);
        kfree(cosa->bouncebuf);
        free_irq(cosa->irq, cosa);
        free_dma(cosa->dma);
        release_region(cosa->datareg, is_8bit(cosa) ? 2 : 4);
    }
    unregister_chrdev(cosa_major, "cosa");
}
module_exit(cosa_exit);

static const struct net_device_ops cosa_ops = {
    .ndo_open       = cosa_net_open,
    .ndo_stop       = cosa_net_close,
    .ndo_change_mtu = hdlc_change_mtu,
    .ndo_start_xmit = hdlc_start_xmit,
    .ndo_do_ioctl   = cosa_net_ioctl,
    .ndo_tx_timeout = cosa_net_timeout,
};

static int cosa_probe(int base, int irq, int dma)
{
    struct cosa_data *cosa = cosa_cards+nr_cards;
    int i, err = 0;

    memset(cosa, 0, sizeof(struct cosa_data));

    /* Checking validity of parameters: */
    /* IRQ should be 2-7 or 10-15; negative IRQ means autoprobe */
    if ((irq >= 0  && irq < 2) || irq > 15 || (irq < 10 && irq > 7)) {
        pr_info("invalid IRQ %d\n", irq);
        return -1;
    }
    /* I/O address should be between 0x100 and 0x3ff and should be
     * multiple of 8. */
    if (base < 0x100 || base > 0x3ff || base & 0x7) {
        pr_info("invalid I/O address 0x%x\n", base);
        return -1;
    }
    /* DMA should be 0,1 or 3-7 */
    if (dma < 0 || dma == 4 || dma > 7) {
        pr_info("invalid DMA %d\n", dma);
        return -1;
    }
    /* and finally, on 16-bit COSA DMA should be 4-7 and 
     * I/O base should not be multiple of 0x10 */
    if (((base & 0x8) && dma < 4) || (!(base & 0x8) && dma > 3)) {
        pr_info("8/16 bit base and DMA mismatch (base=0x%x, dma=%d)\n",
            base, dma);
        return -1;
    }

    cosa->dma = dma;
    cosa->datareg = base;
    cosa->statusreg = is_8bit(cosa)?base+1:base+2;
    spin_lock_init(&cosa->lock);

    if (!request_region(base, is_8bit(cosa)?2:4,"cosa"))
        return -1;
    
    if (cosa_reset_and_read_id(cosa, cosa->id_string) < 0) {
        printk(KERN_DEBUG "probe at 0x%x failed.\n", base);
        err = -1;
        goto err_out;
    }

    /* Test the validity of identification string */
    if (!strncmp(cosa->id_string, "SRP", 3))
        cosa->type = "srp";
    else if (!strncmp(cosa->id_string, "COSA", 4))
        cosa->type = is_8bit(cosa)? "cosa8": "cosa16";
    else {
/* Print a warning only if we are not autoprobing */
#ifndef COSA_ISA_AUTOPROBE
        pr_info("valid signature not found at 0x%x\n", base);
#endif
        err = -1;
        goto err_out;
    }
    /* Update the name of the region now we know the type of card */ 
    release_region(base, is_8bit(cosa)?2:4);
    if (!request_region(base, is_8bit(cosa)?2:4, cosa->type)) {
        printk(KERN_DEBUG "changing name at 0x%x failed.\n", base);
        return -1;
    }

    /* Now do IRQ autoprobe */
    if (irq < 0) {
        unsigned long irqs;
/*      pr_info("IRQ autoprobe\n"); */
        irqs = probe_irq_on();
        /* 
         * Enable interrupt on tx buffer empty (it sure is) 
         * really sure ?
         * FIXME: When this code is not used as module, we should
         * probably call udelay() instead of the interruptible sleep.
         */
        set_current_state(TASK_INTERRUPTIBLE);
        cosa_putstatus(cosa, SR_TX_INT_ENA);
        schedule_timeout(30);
        irq = probe_irq_off(irqs);
        /* Disable all IRQs from the card */
        cosa_putstatus(cosa, 0);
        /* Empty the received data register */
        cosa_getdata8(cosa);

        if (irq < 0) {
            pr_info("multiple interrupts obtained (%d, board at 0x%x)\n",
                irq, cosa->datareg);
            err = -1;
            goto err_out;
        }
        if (irq == 0) {
            pr_info("no interrupt obtained (board at 0x%x)\n",
                cosa->datareg);
        /*  return -1; */
        }
    }

    cosa->irq = irq;
    cosa->num = nr_cards;
    cosa->usage = 0;
    cosa->nchannels = 2;    /* FIXME: how to determine this? */

    if (request_irq(cosa->irq, cosa_interrupt, 0, cosa->type, cosa)) {
        err = -1;
        goto err_out;
    }
    if (request_dma(cosa->dma, cosa->type)) {
        err = -1;
        goto err_out1;
    }
    
    cosa->bouncebuf = kmalloc(COSA_MTU, GFP_KERNEL|GFP_DMA);
    if (!cosa->bouncebuf) {
        err = -ENOMEM;
        goto err_out2;
    }
    sprintf(cosa->name, "cosa%d", cosa->num);

    /* Initialize the per-channel data */
    cosa->chan = kcalloc(cosa->nchannels, sizeof(struct channel_data), GFP_KERNEL);
    if (!cosa->chan) {
        err = -ENOMEM;
        goto err_out3;
    }

    for (i = 0; i < cosa->nchannels; i++) {
        struct channel_data *chan = &cosa->chan[i];

        chan->cosa = cosa;
        chan->num = i;
        sprintf(chan->name, "cosa%dc%d", chan->cosa->num, i);

        /* Initialize the chardev data structures */
        mutex_init(&chan->rlock);
        sema_init(&chan->wsem, 1);

        /* Register the network interface */
        if (!(chan->netdev = alloc_hdlcdev(chan))) {
            pr_warn("%s: alloc_hdlcdev failed\n", chan->name);
            goto err_hdlcdev;
        }
        dev_to_hdlc(chan->netdev)->attach = cosa_net_attach;
        dev_to_hdlc(chan->netdev)->xmit = cosa_net_tx;
        chan->netdev->netdev_ops = &cosa_ops;
        chan->netdev->watchdog_timeo = TX_TIMEOUT;
        chan->netdev->base_addr = chan->cosa->datareg;
        chan->netdev->irq = chan->cosa->irq;
        chan->netdev->dma = chan->cosa->dma;
        if (register_hdlc_device(chan->netdev)) {
            netdev_warn(chan->netdev,
                    "register_hdlc_device() failed\n");
            free_netdev(chan->netdev);
            goto err_hdlcdev;
        }
    }

    pr_info("cosa%d: %s (%s at 0x%x irq %d dma %d), %d channels\n",
        cosa->num, cosa->id_string, cosa->type,
        cosa->datareg, cosa->irq, cosa->dma, cosa->nchannels);

    return nr_cards++;

err_hdlcdev:
    while (i-- > 0) {
        unregister_hdlc_device(cosa->chan[i].netdev);
        free_netdev(cosa->chan[i].netdev);
    }
    kfree(cosa->chan);
err_out3:
    kfree(cosa->bouncebuf);
err_out2:
    free_dma(cosa->dma);
err_out1:
    free_irq(cosa->irq, cosa);
err_out:
    release_region(cosa->datareg,is_8bit(cosa)?2:4);
    pr_notice("cosa%d: allocating resources failed\n", cosa->num);
    return err;
}


/*---------- network device ---------- */

static int cosa_net_attach(struct net_device *dev, unsigned short encoding,
               unsigned short parity)
{
    if (encoding == ENCODING_NRZ && parity == PARITY_CRC16_PR1_CCITT)
        return 0;
    return -EINVAL;
}

static int cosa_net_open(struct net_device *dev)
{
    struct channel_data *chan = dev_to_chan(dev);
    int err;
    unsigned long flags;

    if (!(chan->cosa->firmware_status & COSA_FW_START)) {
        pr_notice("%s: start the firmware first (status %d)\n",
              chan->cosa->name, chan->cosa->firmware_status);
        return -EPERM;
    }
    spin_lock_irqsave(&chan->cosa->lock, flags);
    if (chan->usage != 0) {
        pr_warn("%s: cosa_net_open called with usage count %d\n",
            chan->name, chan->usage);
        spin_unlock_irqrestore(&chan->cosa->lock, flags);
        return -EBUSY;
    }
    chan->setup_rx = cosa_net_setup_rx;
    chan->tx_done = cosa_net_tx_done;
    chan->rx_done = cosa_net_rx_done;
    chan->usage = -1;
    chan->cosa->usage++;
    spin_unlock_irqrestore(&chan->cosa->lock, flags);

    err = hdlc_open(dev);
    if (err) {
        spin_lock_irqsave(&chan->cosa->lock, flags);
        chan->usage = 0;
        chan->cosa->usage--;
        spin_unlock_irqrestore(&chan->cosa->lock, flags);
        return err;
    }

    netif_start_queue(dev);
    cosa_enable_rx(chan);
    return 0;
}

static netdev_tx_t cosa_net_tx(struct sk_buff *skb,
                     struct net_device *dev)
{
    struct channel_data *chan = dev_to_chan(dev);

    netif_stop_queue(dev);

    chan->tx_skb = skb;
    cosa_start_tx(chan, skb->data, skb->len);
    return NETDEV_TX_OK;
}

static void cosa_net_timeout(struct net_device *dev)
{
    struct channel_data *chan = dev_to_chan(dev);

    if (test_bit(RXBIT, &chan->cosa->rxtx)) {
        chan->netdev->stats.rx_errors++;
        chan->netdev->stats.rx_missed_errors++;
    } else {
        chan->netdev->stats.tx_errors++;
        chan->netdev->stats.tx_aborted_errors++;
    }
    cosa_kick(chan->cosa);
    if (chan->tx_skb) {
        dev_kfree_skb(chan->tx_skb);
        chan->tx_skb = NULL;
    }
    netif_wake_queue(dev);
}

static int cosa_net_close(struct net_device *dev)
{
    struct channel_data *chan = dev_to_chan(dev);
    unsigned long flags;

    netif_stop_queue(dev);
    hdlc_close(dev);
    cosa_disable_rx(chan);
    spin_lock_irqsave(&chan->cosa->lock, flags);
    if (chan->rx_skb) {
        kfree_skb(chan->rx_skb);
        chan->rx_skb = NULL;
    }
    if (chan->tx_skb) {
        kfree_skb(chan->tx_skb);
        chan->tx_skb = NULL;
    }
    chan->usage = 0;
    chan->cosa->usage--;
    spin_unlock_irqrestore(&chan->cosa->lock, flags);
    return 0;
}

static char *cosa_net_setup_rx(struct channel_data *chan, int size)
{
    /*
     * We can safely fall back to non-dma-able memory, because we have
     * the cosa->bouncebuf pre-allocated.
     */
    kfree_skb(chan->rx_skb);
    chan->rx_skb = dev_alloc_skb(size);
    if (chan->rx_skb == NULL) {
        pr_notice("%s: Memory squeeze, dropping packet\n", chan->name);
        chan->netdev->stats.rx_dropped++;
        return NULL;
    }
    chan->netdev->trans_start = jiffies;
    return skb_put(chan->rx_skb, size);
}

static int cosa_net_rx_done(struct channel_data *chan)
{
    if (!chan->rx_skb) {
        pr_warn("%s: rx_done with empty skb!\n", chan->name);
        chan->netdev->stats.rx_errors++;
        chan->netdev->stats.rx_frame_errors++;
        return 0;
    }
    chan->rx_skb->protocol = hdlc_type_trans(chan->rx_skb, chan->netdev);
    chan->rx_skb->dev = chan->netdev;
    skb_reset_mac_header(chan->rx_skb);
    chan->netdev->stats.rx_packets++;
    chan->netdev->stats.rx_bytes += chan->cosa->rxsize;
    netif_rx(chan->rx_skb);
    chan->rx_skb = NULL;
    return 0;
}

/* ARGSUSED */
static int cosa_net_tx_done(struct channel_data *chan, int size)
{
    if (!chan->tx_skb) {
        pr_warn("%s: tx_done with empty skb!\n", chan->name);
        chan->netdev->stats.tx_errors++;
        chan->netdev->stats.tx_aborted_errors++;
        return 1;
    }
    dev_kfree_skb_irq(chan->tx_skb);
    chan->tx_skb = NULL;
    chan->netdev->stats.tx_packets++;
    chan->netdev->stats.tx_bytes += size;
    netif_wake_queue(chan->netdev);
    return 1;
}

/*---------- Character device ---------- */

static ssize_t cosa_read(struct file *file,
    char __user *buf, size_t count, loff_t *ppos)
{
    DECLARE_WAITQUEUE(wait, current);
    unsigned long flags;
    struct channel_data *chan = file->private_data;
    struct cosa_data *cosa = chan->cosa;
    char *kbuf;

    if (!(cosa->firmware_status & COSA_FW_START)) {
        pr_notice("%s: start the firmware first (status %d)\n",
              cosa->name, cosa->firmware_status);
        return -EPERM;
    }
    if (mutex_lock_interruptible(&chan->rlock))
        return -ERESTARTSYS;
    
    if ((chan->rxdata = kmalloc(COSA_MTU, GFP_DMA|GFP_KERNEL)) == NULL) {
        pr_info("%s: cosa_read() - OOM\n", cosa->name);
        mutex_unlock(&chan->rlock);
        return -ENOMEM;
    }

    chan->rx_status = 0;
    cosa_enable_rx(chan);
    spin_lock_irqsave(&cosa->lock, flags);
    add_wait_queue(&chan->rxwaitq, &wait);
    while (!chan->rx_status) {
        current->state = TASK_INTERRUPTIBLE;
        spin_unlock_irqrestore(&cosa->lock, flags);
        schedule();
        spin_lock_irqsave(&cosa->lock, flags);
        if (signal_pending(current) && chan->rx_status == 0) {
            chan->rx_status = 1;
            remove_wait_queue(&chan->rxwaitq, &wait);
            current->state = TASK_RUNNING;
            spin_unlock_irqrestore(&cosa->lock, flags);
            mutex_unlock(&chan->rlock);
            return -ERESTARTSYS;
        }
    }
    remove_wait_queue(&chan->rxwaitq, &wait);
    current->state = TASK_RUNNING;
    kbuf = chan->rxdata;
    count = chan->rxsize;
    spin_unlock_irqrestore(&cosa->lock, flags);
    mutex_unlock(&chan->rlock);

    if (copy_to_user(buf, kbuf, count)) {
        kfree(kbuf);
        return -EFAULT;
    }
    kfree(kbuf);
    return count;
}

static char *chrdev_setup_rx(struct channel_data *chan, int size)
{
    /* Expect size <= COSA_MTU */
    chan->rxsize = size;
    return chan->rxdata;
}

static int chrdev_rx_done(struct channel_data *chan)
{
    if (chan->rx_status) { /* Reader has died */
        kfree(chan->rxdata);
        up(&chan->wsem);
    }
    chan->rx_status = 1;
    wake_up_interruptible(&chan->rxwaitq);
    return 1;
}


static ssize_t cosa_write(struct file *file,
    const char __user *buf, size_t count, loff_t *ppos)
{
    DECLARE_WAITQUEUE(wait, current);
    struct channel_data *chan = file->private_data;
    struct cosa_data *cosa = chan->cosa;
    unsigned long flags;
    char *kbuf;

    if (!(cosa->firmware_status & COSA_FW_START)) {
        pr_notice("%s: start the firmware first (status %d)\n",
              cosa->name, cosa->firmware_status);
        return -EPERM;
    }
    if (down_interruptible(&chan->wsem))
        return -ERESTARTSYS;

    if (count > COSA_MTU)
        count = COSA_MTU;
    
    /* Allocate the buffer */
    if ((kbuf = kmalloc(count, GFP_KERNEL|GFP_DMA)) == NULL) {
        pr_notice("%s: cosa_write() OOM - dropping packet\n",
              cosa->name);
        up(&chan->wsem);
        return -ENOMEM;
    }
    if (copy_from_user(kbuf, buf, count)) {
        up(&chan->wsem);
        kfree(kbuf);
        return -EFAULT;
    }
    chan->tx_status=0;
    cosa_start_tx(chan, kbuf, count);

    spin_lock_irqsave(&cosa->lock, flags);
    add_wait_queue(&chan->txwaitq, &wait);
    while (!chan->tx_status) {
        current->state = TASK_INTERRUPTIBLE;
        spin_unlock_irqrestore(&cosa->lock, flags);
        schedule();
        spin_lock_irqsave(&cosa->lock, flags);
        if (signal_pending(current) && chan->tx_status == 0) {
            chan->tx_status = 1;
            remove_wait_queue(&chan->txwaitq, &wait);
            current->state = TASK_RUNNING;
            chan->tx_status = 1;
            spin_unlock_irqrestore(&cosa->lock, flags);
            up(&chan->wsem);
            return -ERESTARTSYS;
        }
    }
    remove_wait_queue(&chan->txwaitq, &wait);
    current->state = TASK_RUNNING;
    up(&chan->wsem);
    spin_unlock_irqrestore(&cosa->lock, flags);
    kfree(kbuf);
    return count;
}

static int chrdev_tx_done(struct channel_data *chan, int size)
{
    if (chan->tx_status) { /* Writer was interrupted */
        kfree(chan->txbuf);
        up(&chan->wsem);
    }
    chan->tx_status = 1;
    wake_up_interruptible(&chan->txwaitq);
    return 1;
}

static unsigned int cosa_poll(struct file *file, poll_table *poll)
{
    pr_info("cosa_poll is here\n");
    return 0;
}

static int cosa_open(struct inode *inode, struct file *file)
{
    struct cosa_data *cosa;
    struct channel_data *chan;
    unsigned long flags;
    int n;
    int ret = 0;

    mutex_lock(&cosa_chardev_mutex);
    if ((n=iminor(file->f_path.dentry->d_inode)>>CARD_MINOR_BITS)
        >= nr_cards) {
        ret = -ENODEV;
        goto out;
    }
    cosa = cosa_cards+n;

    if ((n=iminor(file->f_path.dentry->d_inode)
        & ((1<<CARD_MINOR_BITS)-1)) >= cosa->nchannels) {
        ret = -ENODEV;
        goto out;
    }
    chan = cosa->chan + n;
    
    file->private_data = chan;

    spin_lock_irqsave(&cosa->lock, flags);

    if (chan->usage < 0) { /* in netdev mode */
        spin_unlock_irqrestore(&cosa->lock, flags);
        ret = -EBUSY;
        goto out;
    }
    cosa->usage++;
    chan->usage++;

    chan->tx_done = chrdev_tx_done;
    chan->setup_rx = chrdev_setup_rx;
    chan->rx_done = chrdev_rx_done;
    spin_unlock_irqrestore(&cosa->lock, flags);
out:
    mutex_unlock(&cosa_chardev_mutex);
    return ret;
}

static int cosa_release(struct inode *inode, struct file *file)
{
    struct channel_data *channel = file->private_data;
    struct cosa_data *cosa;
    unsigned long flags;

    cosa = channel->cosa;
    spin_lock_irqsave(&cosa->lock, flags);
    cosa->usage--;
    channel->usage--;
    spin_unlock_irqrestore(&cosa->lock, flags);
    return 0;
}

#ifdef COSA_FASYNC_WORKING
static struct fasync_struct *fasync[256] = { NULL, };

/* To be done ... */
static int cosa_fasync(struct inode *inode, struct file *file, int on)
{
        int port = iminor(inode);

    return fasync_helper(inode, file, on, &fasync[port]);
}
#endif


/* ---------- Ioctls ---------- */

/*
 * Ioctl subroutines can safely be made inline, because they are called
 * only from cosa_ioctl().
 */
static inline int cosa_reset(struct cosa_data *cosa)
{
    char idstring[COSA_MAX_ID_STRING];
    if (cosa->usage > 1)
        pr_info("cosa%d: WARNING: reset requested with cosa->usage > 1 (%d). Odd things may happen.\n",
            cosa->num, cosa->usage);
    cosa->firmware_status &= ~(COSA_FW_RESET|COSA_FW_START);
    if (cosa_reset_and_read_id(cosa, idstring) < 0) {
        pr_notice("cosa%d: reset failed\n", cosa->num);
        return -EIO;
    }
    pr_info("cosa%d: resetting device: %s\n", cosa->num, idstring);
    cosa->firmware_status |= COSA_FW_RESET;
    return 0;
}

/* High-level function to download data into COSA memory. Calls download() */
static inline int cosa_download(struct cosa_data *cosa, void __user *arg)
{
    struct cosa_download d;
    int i;

    if (cosa->usage > 1)
        pr_info("%s: WARNING: download of microcode requested with cosa->usage > 1 (%d). Odd things may happen.\n",
            cosa->name, cosa->usage);
    if (!(cosa->firmware_status & COSA_FW_RESET)) {
        pr_notice("%s: reset the card first (status %d)\n",
              cosa->name, cosa->firmware_status);
        return -EPERM;
    }
    
    if (copy_from_user(&d, arg, sizeof(d)))
        return -EFAULT;

    if (d.addr < 0 || d.addr > COSA_MAX_FIRMWARE_SIZE)
        return -EINVAL;
    if (d.len < 0 || d.len > COSA_MAX_FIRMWARE_SIZE)
        return -EINVAL;


    /* If something fails, force the user to reset the card */
    cosa->firmware_status &= ~(COSA_FW_RESET|COSA_FW_DOWNLOAD);

    i = download(cosa, d.code, d.len, d.addr);
    if (i < 0) {
        pr_notice("cosa%d: microcode download failed: %d\n",
              cosa->num, i);
        return -EIO;
    }
    pr_info("cosa%d: downloading microcode - 0x%04x bytes at 0x%04x\n",
        cosa->num, d.len, d.addr);
    cosa->firmware_status |= COSA_FW_RESET|COSA_FW_DOWNLOAD;
    return 0;
}

/* High-level function to read COSA memory. Calls readmem() */
static inline int cosa_readmem(struct cosa_data *cosa, void __user *arg)
{
    struct cosa_download d;
    int i;

    if (cosa->usage > 1)
        pr_info("cosa%d: WARNING: readmem requested with cosa->usage > 1 (%d). Odd things may happen.\n",
            cosa->num, cosa->usage);
    if (!(cosa->firmware_status & COSA_FW_RESET)) {
        pr_notice("%s: reset the card first (status %d)\n",
              cosa->name, cosa->firmware_status);
        return -EPERM;
    }

    if (copy_from_user(&d, arg, sizeof(d)))
        return -EFAULT;

    /* If something fails, force the user to reset the card */
    cosa->firmware_status &= ~COSA_FW_RESET;

    i = readmem(cosa, d.code, d.len, d.addr);
    if (i < 0) {
        pr_notice("cosa%d: reading memory failed: %d\n", cosa->num, i);
        return -EIO;
    }
    pr_info("cosa%d: reading card memory - 0x%04x bytes at 0x%04x\n",
        cosa->num, d.len, d.addr);
    cosa->firmware_status |= COSA_FW_RESET;
    return 0;
}

/* High-level function to start microcode. Calls startmicrocode(). */
static inline int cosa_start(struct cosa_data *cosa, int address)
{
    int i;

    if (cosa->usage > 1)
        pr_info("cosa%d: WARNING: start microcode requested with cosa->usage > 1 (%d). Odd things may happen.\n",
            cosa->num, cosa->usage);

    if ((cosa->firmware_status & (COSA_FW_RESET|COSA_FW_DOWNLOAD))
        != (COSA_FW_RESET|COSA_FW_DOWNLOAD)) {
        pr_notice("%s: download the microcode and/or reset the card first (status %d)\n",
              cosa->name, cosa->firmware_status);
        return -EPERM;
    }
    cosa->firmware_status &= ~COSA_FW_RESET;
    if ((i=startmicrocode(cosa, address)) < 0) {
        pr_notice("cosa%d: start microcode at 0x%04x failed: %d\n",
              cosa->num, address, i);
        return -EIO;
    }
    pr_info("cosa%d: starting microcode at 0x%04x\n", cosa->num, address);
    cosa->startaddr = address;
    cosa->firmware_status |= COSA_FW_START;
    return 0;
}
        
/* Buffer of size at least COSA_MAX_ID_STRING is expected */
static inline int cosa_getidstr(struct cosa_data *cosa, char __user *string)
{
    int l = strlen(cosa->id_string)+1;
    if (copy_to_user(string, cosa->id_string, l))
        return -EFAULT;
    return l;
}

/* Buffer of size at least COSA_MAX_ID_STRING is expected */
static inline int cosa_gettype(struct cosa_data *cosa, char __user *string)
{
    int l = strlen(cosa->type)+1;
    if (copy_to_user(string, cosa->type, l))
        return -EFAULT;
    return l;
}

static int cosa_ioctl_common(struct cosa_data *cosa,
    struct channel_data *channel, unsigned int cmd, unsigned long arg)
{
    void __user *argp = (void __user *)arg;
    switch (cmd) {
    case COSAIORSET:    /* Reset the device */
        if (!capable(CAP_NET_ADMIN))
            return -EACCES;
        return cosa_reset(cosa);
    case COSAIOSTRT:    /* Start the firmware */
        if (!capable(CAP_SYS_RAWIO))
            return -EACCES;
        return cosa_start(cosa, arg);
    case COSAIODOWNLD:  /* Download the firmware */
        if (!capable(CAP_SYS_RAWIO))
            return -EACCES;
        
        return cosa_download(cosa, argp);
    case COSAIORMEM:
        if (!capable(CAP_SYS_RAWIO))
            return -EACCES;
        return cosa_readmem(cosa, argp);
    case COSAIORTYPE:
        return cosa_gettype(cosa, argp);
    case COSAIORIDSTR:
        return cosa_getidstr(cosa, argp);
    case COSAIONRCARDS:
        return nr_cards;
    case COSAIONRCHANS:
        return cosa->nchannels;
    case COSAIOBMSET:
        if (!capable(CAP_SYS_RAWIO))
            return -EACCES;
        if (is_8bit(cosa))
            return -EINVAL;
        if (arg != COSA_BM_OFF && arg != COSA_BM_ON)
            return -EINVAL;
        cosa->busmaster = arg;
        return 0;
    case COSAIOBMGET:
        return cosa->busmaster;
    }
    return -ENOIOCTLCMD;
}

static int cosa_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
    int rv;
    struct channel_data *chan = dev_to_chan(dev);
    rv = cosa_ioctl_common(chan->cosa, chan, cmd,
                   (unsigned long)ifr->ifr_data);
    if (rv != -ENOIOCTLCMD)
        return rv;
    return hdlc_ioctl(dev, ifr, cmd);
}

static long cosa_chardev_ioctl(struct file *file, unsigned int cmd,
                            unsigned long arg)
{
    struct channel_data *channel = file->private_data;
    struct cosa_data *cosa;
    long ret;

    mutex_lock(&cosa_chardev_mutex);
    cosa = channel->cosa;
    ret = cosa_ioctl_common(cosa, channel, cmd, arg);
    mutex_unlock(&cosa_chardev_mutex);
    return ret;
}


/*---------- HW layer interface ---------- */

/*
 * The higher layer can bind itself to the HW layer by setting the callbacks
 * in the channel_data structure and by using these routines.
 */
static void cosa_enable_rx(struct channel_data *chan)
{
    struct cosa_data *cosa = chan->cosa;

    if (!test_and_set_bit(chan->num, &cosa->rxbitmap))
        put_driver_status(cosa);
}

static void cosa_disable_rx(struct channel_data *chan)
{
    struct cosa_data *cosa = chan->cosa;

    if (test_and_clear_bit(chan->num, &cosa->rxbitmap))
        put_driver_status(cosa);
}

/*
 * FIXME: This routine probably should check for cosa_start_tx() called when
 * the previous transmit is still unfinished. In this case the non-zero
 * return value should indicate to the caller that the queuing(sp?) up
 * the transmit has failed.
 */
static int cosa_start_tx(struct channel_data *chan, char *buf, int len)
{
    struct cosa_data *cosa = chan->cosa;
    unsigned long flags;
#ifdef DEBUG_DATA
    int i;

    pr_info("cosa%dc%d: starting tx(0x%x)",
        chan->cosa->num, chan->num, len);
    for (i=0; i<len; i++)
        pr_cont(" %02x", buf[i]&0xff);
    pr_cont("\n");
#endif
    spin_lock_irqsave(&cosa->lock, flags);
    chan->txbuf = buf;
    chan->txsize = len;
    if (len > COSA_MTU)
        chan->txsize = COSA_MTU;
    spin_unlock_irqrestore(&cosa->lock, flags);

    /* Tell the firmware we are ready */
    set_bit(chan->num, &cosa->txbitmap);
    put_driver_status(cosa);

    return 0;
}

static void put_driver_status(struct cosa_data *cosa)
{
    unsigned long flags;
    int status;

    spin_lock_irqsave(&cosa->lock, flags);

    status = (cosa->rxbitmap ? DRIVER_RX_READY : 0)
        | (cosa->txbitmap ? DRIVER_TX_READY : 0)
        | (cosa->txbitmap? ~(cosa->txbitmap<<DRIVER_TXMAP_SHIFT)
            &DRIVER_TXMAP_MASK : 0);
    if (!cosa->rxtx) {
        if (cosa->rxbitmap|cosa->txbitmap) {
            if (!cosa->enabled) {
                cosa_putstatus(cosa, SR_RX_INT_ENA);
#ifdef DEBUG_IO
                debug_status_out(cosa, SR_RX_INT_ENA);
#endif
                cosa->enabled = 1;
            }
        } else if (cosa->enabled) {
            cosa->enabled = 0;
            cosa_putstatus(cosa, 0);
#ifdef DEBUG_IO
            debug_status_out(cosa, 0);
#endif
        }
        cosa_putdata8(cosa, status);
#ifdef DEBUG_IO
        debug_data_cmd(cosa, status);
#endif
    }
    spin_unlock_irqrestore(&cosa->lock, flags);
}

static void put_driver_status_nolock(struct cosa_data *cosa)
{
    int status;

    status = (cosa->rxbitmap ? DRIVER_RX_READY : 0)
        | (cosa->txbitmap ? DRIVER_TX_READY : 0)
        | (cosa->txbitmap? ~(cosa->txbitmap<<DRIVER_TXMAP_SHIFT)
            &DRIVER_TXMAP_MASK : 0);

    if (cosa->rxbitmap|cosa->txbitmap) {
        cosa_putstatus(cosa, SR_RX_INT_ENA);
#ifdef DEBUG_IO
        debug_status_out(cosa, SR_RX_INT_ENA);
#endif
        cosa->enabled = 1;
    } else {
        cosa_putstatus(cosa, 0);
#ifdef DEBUG_IO
        debug_status_out(cosa, 0);
#endif
        cosa->enabled = 0;
    }
    cosa_putdata8(cosa, status);
#ifdef DEBUG_IO
    debug_data_cmd(cosa, status);
#endif
}

/*
 * The "kickme" function: When the DMA times out, this is called to
 * clean up the driver status.
 * FIXME: Preliminary support, the interface is probably wrong.
 */
static void cosa_kick(struct cosa_data *cosa)
{
    unsigned long flags, flags1;
    char *s = "(probably) IRQ";

    if (test_bit(RXBIT, &cosa->rxtx))
        s = "RX DMA";
    if (test_bit(TXBIT, &cosa->rxtx))
        s = "TX DMA";

    pr_info("%s: %s timeout - restarting\n", cosa->name, s);
    spin_lock_irqsave(&cosa->lock, flags);
    cosa->rxtx = 0;

    flags1 = claim_dma_lock();
    disable_dma(cosa->dma);
    clear_dma_ff(cosa->dma);
    release_dma_lock(flags1);

    /* FIXME: Anything else? */
    udelay(100);
    cosa_putstatus(cosa, 0);
    udelay(100);
    (void) cosa_getdata8(cosa);
    udelay(100);
    cosa_putdata8(cosa, 0);
    udelay(100);
    put_driver_status_nolock(cosa);
    spin_unlock_irqrestore(&cosa->lock, flags);
}

/*
 * Check if the whole buffer is DMA-able. It means it is below the 16M of
 * physical memory and doesn't span the 64k boundary. For now it seems
 * SKB's never do this, but we'll check this anyway.
 */
static int cosa_dma_able(struct channel_data *chan, char *buf, int len)
{
    static int count;
    unsigned long b = (unsigned long)buf;
    if (b+len >= MAX_DMA_ADDRESS)
        return 0;
    if ((b^ (b+len)) & 0x10000) {
        if (count++ < 5)
            pr_info("%s: packet spanning a 64k boundary\n",
                chan->name);
        return 0;
    }
    return 1;
}


/* ---------- The SRP/COSA ROM monitor functions ---------- */

/*
 * Downloading SRP microcode: say "w" to SRP monitor, it answers by "w=",
 * drivers need to say 4-digit hex number meaning start address of the microcode
 * separated by a single space. Monitor replies by saying " =". Now driver
 * has to write 4-digit hex number meaning the last byte address ended
 * by a single space. Monitor has to reply with a space. Now the download
 * begins. After the download monitor replies with "\r\n." (CR LF dot).
 */
static int download(struct cosa_data *cosa, const char __user *microcode, int length, int address)
{
    int i;

    if (put_wait_data(cosa, 'w') == -1) return -1;
    if ((i=get_wait_data(cosa)) != 'w') { printk("dnld: 0x%04x\n",i); return -2;}
    if (get_wait_data(cosa) != '=') return -3;

    if (puthexnumber(cosa, address) < 0) return -4;
    if (put_wait_data(cosa, ' ') == -1) return -10;
    if (get_wait_data(cosa) != ' ') return -11;
    if (get_wait_data(cosa) != '=') return -12;

    if (puthexnumber(cosa, address+length-1) < 0) return -13;
    if (put_wait_data(cosa, ' ') == -1) return -18;
    if (get_wait_data(cosa) != ' ') return -19;

    while (length--) {
        char c;
#ifndef SRP_DOWNLOAD_AT_BOOT
        if (get_user(c, microcode))
            return -23; /* ??? */
#else
        c = *microcode;
#endif
        if (put_wait_data(cosa, c) == -1)
            return -20;
        microcode++;
    }

    if (get_wait_data(cosa) != '\r') return -21;
    if (get_wait_data(cosa) != '\n') return -22;
    if (get_wait_data(cosa) != '.') return -23;
#if 0
    printk(KERN_DEBUG "cosa%d: download completed.\n", cosa->num);
#endif
    return 0;
}


/*
 * Starting microcode is done via the "g" command of the SRP monitor.
 * The chat should be the following: "g" "g=" "<addr><CR>"
 * "<CR><CR><LF><CR><LF>".
 */
static int startmicrocode(struct cosa_data *cosa, int address)
{
    if (put_wait_data(cosa, 'g') == -1) return -1;
    if (get_wait_data(cosa) != 'g') return -2;
    if (get_wait_data(cosa) != '=') return -3;

    if (puthexnumber(cosa, address) < 0) return -4;
    if (put_wait_data(cosa, '\r') == -1) return -5;
    
    if (get_wait_data(cosa) != '\r') return -6;
    if (get_wait_data(cosa) != '\r') return -7;
    if (get_wait_data(cosa) != '\n') return -8;
    if (get_wait_data(cosa) != '\r') return -9;
    if (get_wait_data(cosa) != '\n') return -10;
#if 0
    printk(KERN_DEBUG "cosa%d: microcode started\n", cosa->num);
#endif
    return 0;
}

/*
 * Reading memory is done via the "r" command of the SRP monitor.
 * The chat is the following "r" "r=" "<addr> " " =" "<last_byte> " " "
 * Then driver can read the data and the conversation is finished
 * by SRP monitor sending "<CR><LF>." (dot at the end).
 *
 * This routine is not needed during the normal operation and serves
 * for debugging purposes only.
 */
static int readmem(struct cosa_data *cosa, char __user *microcode, int length, int address)
{
    if (put_wait_data(cosa, 'r') == -1) return -1;
    if ((get_wait_data(cosa)) != 'r') return -2;
    if ((get_wait_data(cosa)) != '=') return -3;

    if (puthexnumber(cosa, address) < 0) return -4;
    if (put_wait_data(cosa, ' ') == -1) return -5;
    if (get_wait_data(cosa) != ' ') return -6;
    if (get_wait_data(cosa) != '=') return -7;

    if (puthexnumber(cosa, address+length-1) < 0) return -8;
    if (put_wait_data(cosa, ' ') == -1) return -9;
    if (get_wait_data(cosa) != ' ') return -10;

    while (length--) {
        char c;
        int i;
        if ((i=get_wait_data(cosa)) == -1) {
            pr_info("0x%04x bytes remaining\n", length);
            return -11;
        }
        c=i;
#if 1
        if (put_user(c, microcode))
            return -23; /* ??? */
#else
        *microcode = c;
#endif
        microcode++;
    }

    if (get_wait_data(cosa) != '\r') return -21;
    if (get_wait_data(cosa) != '\n') return -22;
    if (get_wait_data(cosa) != '.') return -23;
#if 0
    printk(KERN_DEBUG "cosa%d: readmem completed.\n", cosa->num);
#endif
    return 0;
}

/*
 * This function resets the device and reads the initial prompt
 * of the device's ROM monitor.
 */
static int cosa_reset_and_read_id(struct cosa_data *cosa, char *idstring)
{
    int i=0, id=0, prev=0, curr=0;

    /* Reset the card ... */
    cosa_putstatus(cosa, 0);
    cosa_getdata8(cosa);
    cosa_putstatus(cosa, SR_RST);
#ifdef MODULE
    msleep(500);
#else
    udelay(5*100000);
#endif
    /* Disable all IRQs from the card */
    cosa_putstatus(cosa, 0);

    /*
     * Try to read the ID string. The card then prints out the
     * identification string ended by the "\n\x2e".
     *
     * The following loop is indexed through i (instead of id)
     * to avoid looping forever when for any reason
     * the port returns '\r', '\n' or '\x2e' permanently.
     */
    for (i=0; i<COSA_MAX_ID_STRING-1; i++, prev=curr) {
        if ((curr = get_wait_data(cosa)) == -1) {
            return -1;
        }
        curr &= 0xff;
        if (curr != '\r' && curr != '\n' && curr != 0x2e)
            idstring[id++] = curr;
        if (curr == 0x2e && prev == '\n')
            break;
    }
    /* Perhaps we should fail when i==COSA_MAX_ID_STRING-1 ? */
    idstring[id] = '\0';
    return id;
}


/* ---------- Auxiliary routines for COSA/SRP monitor ---------- */

/*
 * This routine gets the data byte from the card waiting for the SR_RX_RDY
 * bit to be set in a loop. It should be used in the exceptional cases
 * only (for example when resetting the card or downloading the firmware.
 */
static int get_wait_data(struct cosa_data *cosa)
{
    int retries = 1000;

    while (--retries) {
        /* read data and return them */
        if (cosa_getstatus(cosa) & SR_RX_RDY) {
            short r;
            r = cosa_getdata8(cosa);
#if 0
            pr_info("get_wait_data returning after %d retries\n",
                999-retries);
#endif
            return r;
        }
        /* sleep if not ready to read */
        schedule_timeout_interruptible(1);
    }
    pr_info("timeout in get_wait_data (status 0x%x)\n",
        cosa_getstatus(cosa));
    return -1;
}

/*
 * This routine puts the data byte to the card waiting for the SR_TX_RDY
 * bit to be set in a loop. It should be used in the exceptional cases
 * only (for example when resetting the card or downloading the firmware).
 */
static int put_wait_data(struct cosa_data *cosa, int data)
{
    int retries = 1000;
    while (--retries) {
        /* read data and return them */
        if (cosa_getstatus(cosa) & SR_TX_RDY) {
            cosa_putdata8(cosa, data);
#if 0
            pr_info("Putdata: %d retries\n", 999-retries);
#endif
            return 0;
        }
#if 0
        /* sleep if not ready to read */
        schedule_timeout_interruptible(1);
#endif
    }
    pr_info("cosa%d: timeout in put_wait_data (status 0x%x)\n",
        cosa->num, cosa_getstatus(cosa));
    return -1;
}
    
/* 
 * The following routine puts the hexadecimal number into the SRP monitor
 * and verifies the proper echo of the sent bytes. Returns 0 on success,
 * negative number on failure (-1,-3,-5,-7) means that put_wait_data() failed,
 * (-2,-4,-6,-8) means that reading echo failed.
 */
static int puthexnumber(struct cosa_data *cosa, int number)
{
    char temp[5];
    int i;

    /* Well, I should probably replace this by something faster. */
    sprintf(temp, "%04X", number);
    for (i=0; i<4; i++) {
        if (put_wait_data(cosa, temp[i]) == -1) {
            pr_notice("cosa%d: puthexnumber failed to write byte %d\n",
                  cosa->num, i);
            return -1-2*i;
        }
        if (get_wait_data(cosa) != temp[i]) {
            pr_notice("cosa%d: puthexhumber failed to read echo of byte %d\n",
                  cosa->num, i);
            return -2-2*i;
        }
    }
    return 0;
}


/* ---------- Interrupt routines ---------- */

/*
 * There are three types of interrupt:
 * At the beginning of transmit - this handled is in tx_interrupt(),
 * at the beginning of receive - it is in rx_interrupt() and
 * at the end of transmit/receive - it is the eot_interrupt() function.
 * These functions are multiplexed by cosa_interrupt() according to the
 * COSA status byte. I have moved the rx/tx/eot interrupt handling into
 * separate functions to make it more readable. These functions are inline,
 * so there should be no overhead of function call.
 * 
 * In the COSA bus-master mode, we need to tell the card the address of a
 * buffer. Unfortunately, COSA may be too slow for us, so we must busy-wait.
 * It's time to use the bottom half :-(
 */

/*
 * Transmit interrupt routine - called when COSA is willing to obtain
 * data from the OS. The most tricky part of the routine is selection
 * of channel we (OS) want to send packet for. For SRP we should probably
 * use the round-robin approach. The newer COSA firmwares have a simple
 * flow-control - in the status word has bits 2 and 3 set to 1 means that the
 * channel 0 or 1 doesn't want to receive data.
 *
 * It seems there is a bug in COSA firmware (need to trace it further):
 * When the driver status says that the kernel has no more data for transmit
 * (e.g. at the end of TX DMA) and then the kernel changes its mind
 * (e.g. new packet is queued to hard_start_xmit()), the card issues
 * the TX interrupt but does not mark the channel as ready-to-transmit.
 * The fix seems to be to push the packet to COSA despite its request.
 * We first try to obey the card's opinion, and then fall back to forced TX.
 */
static inline void tx_interrupt(struct cosa_data *cosa, int status)
{
    unsigned long flags, flags1;
#ifdef DEBUG_IRQS
    pr_info("cosa%d: SR_DOWN_REQUEST status=0x%04x\n", cosa->num, status);
#endif
    spin_lock_irqsave(&cosa->lock, flags);
    set_bit(TXBIT, &cosa->rxtx);
    if (!test_bit(IRQBIT, &cosa->rxtx)) {
        /* flow control, see the comment above */
        int i=0;
        if (!cosa->txbitmap) {
            pr_warn("%s: No channel wants data in TX IRQ. Expect DMA timeout.\n",
                cosa->name);
            put_driver_status_nolock(cosa);
            clear_bit(TXBIT, &cosa->rxtx);
            spin_unlock_irqrestore(&cosa->lock, flags);
            return;
        }
        while (1) {
            cosa->txchan++;
            i++;
            if (cosa->txchan >= cosa->nchannels)
                cosa->txchan = 0;
            if (!(cosa->txbitmap & (1<<cosa->txchan)))
                continue;
            if (~status & (1 << (cosa->txchan+DRIVER_TXMAP_SHIFT)))
                break;
            /* in second pass, accept first ready-to-TX channel */
            if (i > cosa->nchannels) {
                /* Can be safely ignored */
#ifdef DEBUG_IRQS
                printk(KERN_DEBUG "%s: Forcing TX "
                    "to not-ready channel %d\n",
                    cosa->name, cosa->txchan);
#endif
                break;
            }
        }

        cosa->txsize = cosa->chan[cosa->txchan].txsize;
        if (cosa_dma_able(cosa->chan+cosa->txchan,
            cosa->chan[cosa->txchan].txbuf, cosa->txsize)) {
            cosa->txbuf = cosa->chan[cosa->txchan].txbuf;
        } else {
            memcpy(cosa->bouncebuf, cosa->chan[cosa->txchan].txbuf,
                cosa->txsize);
            cosa->txbuf = cosa->bouncebuf;
        }
    }

    if (is_8bit(cosa)) {
        if (!test_bit(IRQBIT, &cosa->rxtx)) {
            cosa_putstatus(cosa, SR_TX_INT_ENA);
            cosa_putdata8(cosa, ((cosa->txchan << 5) & 0xe0)|
                ((cosa->txsize >> 8) & 0x1f));
#ifdef DEBUG_IO
            debug_status_out(cosa, SR_TX_INT_ENA);
            debug_data_out(cosa, ((cosa->txchan << 5) & 0xe0)|
                                ((cosa->txsize >> 8) & 0x1f));
            debug_data_in(cosa, cosa_getdata8(cosa));
#else
            cosa_getdata8(cosa);
#endif
            set_bit(IRQBIT, &cosa->rxtx);
            spin_unlock_irqrestore(&cosa->lock, flags);
            return;
        } else {
            clear_bit(IRQBIT, &cosa->rxtx);
            cosa_putstatus(cosa, 0);
            cosa_putdata8(cosa, cosa->txsize&0xff);
#ifdef DEBUG_IO
            debug_status_out(cosa, 0);
            debug_data_out(cosa, cosa->txsize&0xff);
#endif
        }
    } else {
        cosa_putstatus(cosa, SR_TX_INT_ENA);
        cosa_putdata16(cosa, ((cosa->txchan<<13) & 0xe000)
            | (cosa->txsize & 0x1fff));
#ifdef DEBUG_IO
        debug_status_out(cosa, SR_TX_INT_ENA);
        debug_data_out(cosa, ((cosa->txchan<<13) & 0xe000)
                        | (cosa->txsize & 0x1fff));
        debug_data_in(cosa, cosa_getdata8(cosa));
        debug_status_out(cosa, 0);
#else
        cosa_getdata8(cosa);
#endif
        cosa_putstatus(cosa, 0);
    }

    if (cosa->busmaster) {
        unsigned long addr = virt_to_bus(cosa->txbuf);
        int count=0;
        pr_info("busmaster IRQ\n");
        while (!(cosa_getstatus(cosa)&SR_TX_RDY)) {
            count++;
            udelay(10);
            if (count > 1000) break;
        }
        pr_info("status %x\n", cosa_getstatus(cosa));
        pr_info("ready after %d loops\n", count);
        cosa_putdata16(cosa, (addr >> 16)&0xffff);

        count = 0;
        while (!(cosa_getstatus(cosa)&SR_TX_RDY)) {
            count++;
            if (count > 1000) break;
            udelay(10);
        }
        pr_info("ready after %d loops\n", count);
        cosa_putdata16(cosa, addr &0xffff);
        flags1 = claim_dma_lock();
        set_dma_mode(cosa->dma, DMA_MODE_CASCADE);
        enable_dma(cosa->dma);
        release_dma_lock(flags1);
    } else {
        /* start the DMA */
        flags1 = claim_dma_lock();
        disable_dma(cosa->dma);
        clear_dma_ff(cosa->dma);
        set_dma_mode(cosa->dma, DMA_MODE_WRITE);
        set_dma_addr(cosa->dma, virt_to_bus(cosa->txbuf));
        set_dma_count(cosa->dma, cosa->txsize);
        enable_dma(cosa->dma);
        release_dma_lock(flags1);
    }
    cosa_putstatus(cosa, SR_TX_DMA_ENA|SR_USR_INT_ENA);
#ifdef DEBUG_IO
    debug_status_out(cosa, SR_TX_DMA_ENA|SR_USR_INT_ENA);
#endif
    spin_unlock_irqrestore(&cosa->lock, flags);
}

static inline void rx_interrupt(struct cosa_data *cosa, int status)
{
    unsigned long flags;
#ifdef DEBUG_IRQS
    pr_info("cosa%d: SR_UP_REQUEST\n", cosa->num);
#endif

    spin_lock_irqsave(&cosa->lock, flags);
    set_bit(RXBIT, &cosa->rxtx);

    if (is_8bit(cosa)) {
        if (!test_bit(IRQBIT, &cosa->rxtx)) {
            set_bit(IRQBIT, &cosa->rxtx);
            put_driver_status_nolock(cosa);
            cosa->rxsize = cosa_getdata8(cosa) <<8;
#ifdef DEBUG_IO
            debug_data_in(cosa, cosa->rxsize >> 8);
#endif
            spin_unlock_irqrestore(&cosa->lock, flags);
            return;
        } else {
            clear_bit(IRQBIT, &cosa->rxtx);
            cosa->rxsize |= cosa_getdata8(cosa) & 0xff;
#ifdef DEBUG_IO
            debug_data_in(cosa, cosa->rxsize & 0xff);
#endif
#if 0
            pr_info("cosa%d: receive rxsize = (0x%04x)\n",
                cosa->num, cosa->rxsize);
#endif
        }
    } else {
        cosa->rxsize = cosa_getdata16(cosa);
#ifdef DEBUG_IO
        debug_data_in(cosa, cosa->rxsize);
#endif
#if 0
        pr_info("cosa%d: receive rxsize = (0x%04x)\n",
            cosa->num, cosa->rxsize);
#endif
    }
    if (((cosa->rxsize & 0xe000) >> 13) >= cosa->nchannels) {
        pr_warn("%s: rx for unknown channel (0x%04x)\n",
            cosa->name, cosa->rxsize);
        spin_unlock_irqrestore(&cosa->lock, flags);
        goto reject;
    }
    cosa->rxchan = cosa->chan + ((cosa->rxsize & 0xe000) >> 13);
    cosa->rxsize &= 0x1fff;
    spin_unlock_irqrestore(&cosa->lock, flags);

    cosa->rxbuf = NULL;
    if (cosa->rxchan->setup_rx)
        cosa->rxbuf = cosa->rxchan->setup_rx(cosa->rxchan, cosa->rxsize);

    if (!cosa->rxbuf) {
reject:     /* Reject the packet */
        pr_info("cosa%d: rejecting packet on channel %d\n",
            cosa->num, cosa->rxchan->num);
        cosa->rxbuf = cosa->bouncebuf;
    }

    /* start the DMA */
    flags = claim_dma_lock();
    disable_dma(cosa->dma);
    clear_dma_ff(cosa->dma);
    set_dma_mode(cosa->dma, DMA_MODE_READ);
    if (cosa_dma_able(cosa->rxchan, cosa->rxbuf, cosa->rxsize & 0x1fff)) {
        set_dma_addr(cosa->dma, virt_to_bus(cosa->rxbuf));
    } else {
        set_dma_addr(cosa->dma, virt_to_bus(cosa->bouncebuf));
    }
    set_dma_count(cosa->dma, (cosa->rxsize&0x1fff));
    enable_dma(cosa->dma);
    release_dma_lock(flags);
    spin_lock_irqsave(&cosa->lock, flags);
    cosa_putstatus(cosa, SR_RX_DMA_ENA|SR_USR_INT_ENA);
    if (!is_8bit(cosa) && (status & SR_TX_RDY))
        cosa_putdata8(cosa, DRIVER_RX_READY);
#ifdef DEBUG_IO
    debug_status_out(cosa, SR_RX_DMA_ENA|SR_USR_INT_ENA);
    if (!is_8bit(cosa) && (status & SR_TX_RDY))
        debug_data_cmd(cosa, DRIVER_RX_READY);
#endif
    spin_unlock_irqrestore(&cosa->lock, flags);
}

static inline void eot_interrupt(struct cosa_data *cosa, int status)
{
    unsigned long flags, flags1;
    spin_lock_irqsave(&cosa->lock, flags);
    flags1 = claim_dma_lock();
    disable_dma(cosa->dma);
    clear_dma_ff(cosa->dma);
    release_dma_lock(flags1);
    if (test_bit(TXBIT, &cosa->rxtx)) {
        struct channel_data *chan = cosa->chan+cosa->txchan;
        if (chan->tx_done)
            if (chan->tx_done(chan, cosa->txsize))
                clear_bit(chan->num, &cosa->txbitmap);
    } else if (test_bit(RXBIT, &cosa->rxtx)) {
#ifdef DEBUG_DATA
    {
        int i;
        pr_info("cosa%dc%d: done rx(0x%x)",
            cosa->num, cosa->rxchan->num, cosa->rxsize);
        for (i=0; i<cosa->rxsize; i++)
            pr_cont(" %02x", cosa->rxbuf[i]&0xff);
        pr_cont("\n");
    }
#endif
        /* Packet for unknown channel? */
        if (cosa->rxbuf == cosa->bouncebuf)
            goto out;
        if (!cosa_dma_able(cosa->rxchan, cosa->rxbuf, cosa->rxsize))
            memcpy(cosa->rxbuf, cosa->bouncebuf, cosa->rxsize);
        if (cosa->rxchan->rx_done)
            if (cosa->rxchan->rx_done(cosa->rxchan))
                clear_bit(cosa->rxchan->num, &cosa->rxbitmap);
    } else {
        pr_notice("cosa%d: unexpected EOT interrupt\n", cosa->num);
    }
    /*
     * Clear the RXBIT, TXBIT and IRQBIT (the latest should be
     * cleared anyway). We should do it as soon as possible
     * so that we can tell the COSA we are done and to give it a time
     * for recovery.
     */
out:
    cosa->rxtx = 0;
    put_driver_status_nolock(cosa);
    spin_unlock_irqrestore(&cosa->lock, flags);
}

static irqreturn_t cosa_interrupt(int irq, void *cosa_)
{
    unsigned status;
    int count = 0;
    struct cosa_data *cosa = cosa_;
again:
    status = cosa_getstatus(cosa);
#ifdef DEBUG_IRQS
    pr_info("cosa%d: got IRQ, status 0x%02x\n", cosa->num, status & 0xff);
#endif
#ifdef DEBUG_IO
    debug_status_in(cosa, status);
#endif
    switch (status & SR_CMD_FROM_SRP_MASK) {
    case SR_DOWN_REQUEST:
        tx_interrupt(cosa, status);
        break;
    case SR_UP_REQUEST:
        rx_interrupt(cosa, status);
        break;
    case SR_END_OF_TRANSFER:
        eot_interrupt(cosa, status);
        break;
    default:
        /* We may be too fast for SRP. Try to wait a bit more. */
        if (count++ < 100) {
            udelay(100);
            goto again;
        }
        pr_info("cosa%d: unknown status 0x%02x in IRQ after %d retries\n",
            cosa->num, status & 0xff, count);
    }
#ifdef DEBUG_IRQS
    if (count)
        pr_info("%s: %d-times got unknown status in IRQ\n",
            cosa->name, count);
    else
        pr_info("%s: returning from IRQ\n", cosa->name);
#endif
    return IRQ_HANDLED;
}


/* ---------- I/O debugging routines ---------- */
/*
 * These routines can be used to monitor COSA/SRP I/O and to printk()
 * the data being transferred on the data and status I/O port in a
 * readable way.
 */

#ifdef DEBUG_IO
static void debug_status_in(struct cosa_data *cosa, int status)
{
    char *s;
    switch (status & SR_CMD_FROM_SRP_MASK) {
    case SR_UP_REQUEST:
        s = "RX_REQ";
        break;
    case SR_DOWN_REQUEST:
        s = "TX_REQ";
        break;
    case SR_END_OF_TRANSFER:
        s = "ET_REQ";
        break;
    default:
        s = "NO_REQ";
        break;
    }
    pr_info("%s: IO: status -> 0x%02x (%s%s%s%s)\n",
        cosa->name,
        status,
        status & SR_USR_RQ ? "USR_RQ|" : "",
        status & SR_TX_RDY ? "TX_RDY|" : "",
        status & SR_RX_RDY ? "RX_RDY|" : "",
        s);
}

static void debug_status_out(struct cosa_data *cosa, int status)
{
    pr_info("%s: IO: status <- 0x%02x (%s%s%s%s%s%s)\n",
        cosa->name,
        status,
        status & SR_RX_DMA_ENA  ? "RXDMA|"  : "!rxdma|",
        status & SR_TX_DMA_ENA  ? "TXDMA|"  : "!txdma|",
        status & SR_RST         ? "RESET|"  : "",
        status & SR_USR_INT_ENA ? "USRINT|" : "!usrint|",
        status & SR_TX_INT_ENA  ? "TXINT|"  : "!txint|",
        status & SR_RX_INT_ENA  ? "RXINT"   : "!rxint");
}

static void debug_data_in(struct cosa_data *cosa, int data)
{
    pr_info("%s: IO: data -> 0x%04x\n", cosa->name, data);
}

static void debug_data_out(struct cosa_data *cosa, int data)
{
    pr_info("%s: IO: data <- 0x%04x\n", cosa->name, data);
}

static void debug_data_cmd(struct cosa_data *cosa, int data)
{
    pr_info("%s: IO: data <- 0x%04x (%s|%s)\n",
        cosa->name, data,
        data & SR_RDY_RCV ? "RX_RDY" : "!rx_rdy",
        data & SR_RDY_SND ? "TX_RDY" : "!tx_rdy");
}
#endif

/* EOF -- this file has not been truncated */