adummy.c

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/*
 * adummy.c: a dummy ATM driver
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <asm/io.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>

#include <linux/atmdev.h>
#include <linux/atm.h>
#include <linux/sonet.h>

/* version definition */

#define DRV_VERSION "1.0"

#define DEV_LABEL "adummy"

#define ADUMMY_DEV(dev) ((struct adummy_dev *) (dev)->dev_data)

struct adummy_dev {
    struct atm_dev *atm_dev;

    struct list_head entry;
};

/* globals */

static LIST_HEAD(adummy_devs);

static ssize_t __set_signal(struct device *dev,
        struct device_attribute *attr,
        const char *buf, size_t len)
{
    struct atm_dev *atm_dev = container_of(dev, struct atm_dev, class_dev);
    int signal;

    if (sscanf(buf, "%d", &signal) == 1) {

        if (signal < ATM_PHY_SIG_LOST || signal > ATM_PHY_SIG_FOUND)
            signal = ATM_PHY_SIG_UNKNOWN;

        atm_dev_signal_change(atm_dev, signal);
        return 1;
    }
    return -EINVAL;
}

static ssize_t __show_signal(struct device *dev,
    struct device_attribute *attr, char *buf)
{
    struct atm_dev *atm_dev = container_of(dev, struct atm_dev, class_dev);
    return sprintf(buf, "%d\n", atm_dev->signal);
}
static DEVICE_ATTR(signal, 0644, __show_signal, __set_signal);

static struct attribute *adummy_attrs[] = {
    &dev_attr_signal.attr,
    NULL
};

static struct attribute_group adummy_group_attrs = {
    .name = NULL, /* We want them in dev's root folder */
    .attrs = adummy_attrs
};

static int __init
adummy_start(struct atm_dev *dev)
{
    dev->ci_range.vpi_bits = 4;
    dev->ci_range.vci_bits = 12;

    return 0;
}

static int
adummy_open(struct atm_vcc *vcc)
{
    short vpi = vcc->vpi;
    int vci = vcc->vci;

    if (vci == ATM_VCI_UNSPEC || vpi == ATM_VPI_UNSPEC)
        return 0;

    set_bit(ATM_VF_ADDR, &vcc->flags);
    set_bit(ATM_VF_READY, &vcc->flags);

    return 0;
}

static void
adummy_close(struct atm_vcc *vcc)
{
    clear_bit(ATM_VF_READY, &vcc->flags);
    clear_bit(ATM_VF_ADDR, &vcc->flags);
}

static int
adummy_send(struct atm_vcc *vcc, struct sk_buff *skb)
{
    if (vcc->pop)
        vcc->pop(vcc, skb);
    else
        dev_kfree_skb_any(skb);
    atomic_inc(&vcc->stats->tx);

    return 0;
}

static int
adummy_proc_read(struct atm_dev *dev, loff_t *pos, char *page)
{
    int left = *pos;

    if (!left--)
        return sprintf(page, "version %s\n", DRV_VERSION);

    return 0;
}

static struct atmdev_ops adummy_ops =
{
    .open =     adummy_open,
    .close =    adummy_close,   
    .send =     adummy_send,
    .proc_read =    adummy_proc_read,
    .owner =    THIS_MODULE
};

static int __init adummy_init(void)
{
    struct atm_dev *atm_dev;
    struct adummy_dev *adummy_dev;
    int err = 0;

    printk(KERN_ERR "adummy: version %s\n", DRV_VERSION);

    adummy_dev = kzalloc(sizeof(struct adummy_dev),
                           GFP_KERNEL);
    if (!adummy_dev) {
        printk(KERN_ERR DEV_LABEL ": kzalloc() failed\n");
        err = -ENOMEM;
        goto out;
    }
    atm_dev = atm_dev_register(DEV_LABEL, NULL, &adummy_ops, -1, NULL);
    if (!atm_dev) {
        printk(KERN_ERR DEV_LABEL ": atm_dev_register() failed\n");
        err = -ENODEV;
        goto out_kfree;
    }

    adummy_dev->atm_dev = atm_dev;
    atm_dev->dev_data = adummy_dev;

    if (sysfs_create_group(&atm_dev->class_dev.kobj, &adummy_group_attrs))
        dev_err(&atm_dev->class_dev, "Could not register attrs for adummy\n");

    if (adummy_start(atm_dev)) {
        printk(KERN_ERR DEV_LABEL ": adummy_start() failed\n");
        err = -ENODEV;
        goto out_unregister;
    }

    list_add(&adummy_dev->entry, &adummy_devs);
out:
    return err;

out_unregister:
    atm_dev_deregister(atm_dev);
out_kfree:
    kfree(adummy_dev);
    goto out;
}

static void __exit adummy_cleanup(void)
{
    struct adummy_dev *adummy_dev, *next;

    list_for_each_entry_safe(adummy_dev, next, &adummy_devs, entry) {
        atm_dev_deregister(adummy_dev->atm_dev);
        kfree(adummy_dev);
    }
}

module_init(adummy_init);
module_exit(adummy_cleanup);

MODULE_AUTHOR("chas williams <[email protected]>");
MODULE_DESCRIPTION("dummy ATM driver");
MODULE_LICENSE("GPL");