drivers/atm/adummy.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * adummy.c: a dummy ATM driver
   4  */
   5
   6 #include <linux/module.h>
   7 #include <linux/kernel.h>
   8 #include <linux/skbuff.h>
   9 #include <linux/errno.h>
  10 #include <linux/types.h>
  11 #include <linux/string.h>
  12 #include <linux/delay.h>
  13 #include <linux/init.h>
  14 #include <linux/mm.h>
  15 #include <linux/timer.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/slab.h>
  18 #include <asm/io.h>
  19 #include <asm/byteorder.h>
  20 #include <linux/uaccess.h>
  21
  22 #include <linux/atmdev.h>
  23 #include <linux/atm.h>
  24 #include <linux/sonet.h>
  25
  26 /* version definition */
  27
  28 #define DRV_VERSION "1.0"
  29
  30 #define DEV_LABEL "adummy"
  31
  32 #define ADUMMY_DEV(dev) ((struct adummy_dev *) (dev)->dev_data)
  33
  34 struct adummy_dev {
  35         struct atm_dev *atm_dev;
  36
  37         struct list_head entry;
  38 };
  39
  40 /* globals */
  41
  42 static LIST_HEAD(adummy_devs);
  43
  44 static ssize_t __set_signal(struct device *dev,
  45                 struct device_attribute *attr,
  46                 const char *buf, size_t len)
  47 {
  48         struct atm_dev *atm_dev = container_of(dev, struct atm_dev, class_dev);
  49         int signal;
  50
  51         if (sscanf(buf, "%d", &signal) == 1) {
  52
  53                 if (signal < ATM_PHY_SIG_LOST || signal > ATM_PHY_SIG_FOUND)
  54                         signal = ATM_PHY_SIG_UNKNOWN;
  55
  56                 atm_dev_signal_change(atm_dev, signal);
  57                 return 1;
  58         }
  59         return -EINVAL;
  60 }
  61
  62 static ssize_t __show_signal(struct device *dev,
  63         struct device_attribute *attr, char *buf)
  64 {
  65         struct atm_dev *atm_dev = container_of(dev, struct atm_dev, class_dev);
  66         return sprintf(buf, "%d\n", atm_dev->signal);
  67 }
  68 static DEVICE_ATTR(signal, 0644, __show_signal, __set_signal);
  69
  70 static struct attribute *adummy_attrs[] = {
  71         &dev_attr_signal.attr,
  72         NULL
  73 };
  74
  75 static const struct attribute_group adummy_group_attrs = {
  76         .name = NULL, /* We want them in dev's root folder */
  77         .attrs = adummy_attrs
  78 };
  79
  80 static int __init
  81 adummy_start(struct atm_dev *dev)
  82 {
  83         dev->ci_range.vpi_bits = 4;
  84         dev->ci_range.vci_bits = 12;
  85
  86         return 0;
  87 }
  88
  89 static int
  90 adummy_open(struct atm_vcc *vcc)
  91 {
  92         short vpi = vcc->vpi;
  93         int vci = vcc->vci;
  94
  95         if (vci == ATM_VCI_UNSPEC || vpi == ATM_VPI_UNSPEC)
  96                 return 0;
  97
  98         set_bit(ATM_VF_ADDR, &vcc->flags);
  99         set_bit(ATM_VF_READY, &vcc->flags);
 100
 101         return 0;
 102 }
 103
 104 static void
 105 adummy_close(struct atm_vcc *vcc)
 106 {
 107         clear_bit(ATM_VF_READY, &vcc->flags);
 108         clear_bit(ATM_VF_ADDR, &vcc->flags);
 109 }
 110
 111 static int
 112 adummy_send(struct atm_vcc *vcc, struct sk_buff *skb)
 113 {
 114         if (vcc->pop)
 115                 vcc->pop(vcc, skb);
 116         else
 117                 dev_kfree_skb_any(skb);
 118         atomic_inc(&vcc->stats->tx);
 119
 120         return 0;
 121 }
 122
 123 static int
 124 adummy_proc_read(struct atm_dev *dev, loff_t *pos, char *page)
 125 {
 126         int left = *pos;
 127
 128         if (!left--)
 129                 return sprintf(page, "version %s\n", DRV_VERSION);
 130
 131         return 0;
 132 }
 133
 134 static const struct atmdev_ops adummy_ops =
 135 {
 136         .open =         adummy_open,
 137         .close =        adummy_close,
 138         .send =         adummy_send,
 139         .proc_read =    adummy_proc_read,
 140         .owner =        THIS_MODULE
 141 };
 142
 143 static int __init adummy_init(void)
 144 {
 145         struct atm_dev *atm_dev;
 146         struct adummy_dev *adummy_dev;
 147         int err = 0;
 148
 149         printk(KERN_ERR "adummy: version %s\n", DRV_VERSION);
 150
 151         adummy_dev = kzalloc(sizeof(struct adummy_dev),
 152                                                    GFP_KERNEL);
 153         if (!adummy_dev) {
 154                 printk(KERN_ERR DEV_LABEL ": kzalloc() failed\n");
 155                 err = -ENOMEM;
 156                 goto out;
 157         }
 158         atm_dev = atm_dev_register(DEV_LABEL, NULL, &adummy_ops, -1, NULL);
 159         if (!atm_dev) {
 160                 printk(KERN_ERR DEV_LABEL ": atm_dev_register() failed\n");
 161                 err = -ENODEV;
 162                 goto out_kfree;
 163         }
 164
 165         adummy_dev->atm_dev = atm_dev;
 166         atm_dev->dev_data = adummy_dev;
 167
 168         if (sysfs_create_group(&atm_dev->class_dev.kobj, &adummy_group_attrs))
 169                 dev_err(&atm_dev->class_dev, "Could not register attrs for adummy\n");
 170
 171         if (adummy_start(atm_dev)) {
 172                 printk(KERN_ERR DEV_LABEL ": adummy_start() failed\n");
 173                 err = -ENODEV;
 174                 goto out_unregister;
 175         }
 176
 177         list_add(&adummy_dev->entry, &adummy_devs);
 178 out:
 179         return err;
 180
 181 out_unregister:
 182         atm_dev_deregister(atm_dev);
 183 out_kfree:
 184         kfree(adummy_dev);
 185         goto out;
 186 }
 187
 188 static void __exit adummy_cleanup(void)
 189 {
 190         struct adummy_dev *adummy_dev, *next;
 191
 192         list_for_each_entry_safe(adummy_dev, next, &adummy_devs, entry) {
 193                 atm_dev_deregister(adummy_dev->atm_dev);
 194                 kfree(adummy_dev);
 195         }
 196 }
 197
 198 module_init(adummy_init);
 199 module_exit(adummy_cleanup);
 200
 201 MODULE_AUTHOR("chas williams <chas@cmf.nrl.navy.mil>");
 202 MODULE_DESCRIPTION("dummy ATM driver");
 203 MODULE_LICENSE("GPL");