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
34struct adummy_dev {
35	struct atm_dev *atm_dev;
36
37	struct list_head entry;
38};
39
40/* globals */
41
42static LIST_HEAD(adummy_devs);
43
44static 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
62static 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}
68static DEVICE_ATTR(signal, 0644, __show_signal, __set_signal);
69
70static struct attribute *adummy_attrs[] = {
71	&dev_attr_signal.attr,
72	NULL
73};
74
75static const struct attribute_group adummy_group_attrs = {
76	.name = NULL, /* We want them in dev's root folder */
77	.attrs = adummy_attrs
78};
79
80static int __init
81adummy_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
89static int
90adummy_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
104static void
105adummy_close(struct atm_vcc *vcc)
106{
107	clear_bit(ATM_VF_READY, &vcc->flags);
108	clear_bit(ATM_VF_ADDR, &vcc->flags);
109}
110
111static int
112adummy_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
123static int
124adummy_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
134static 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
143static 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);
178out:
179	return err;
180
181out_unregister:
182	atm_dev_deregister(atm_dev);
183out_kfree:
184	kfree(adummy_dev);
185	goto out;
186}
187
188static 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
198module_init(adummy_init);
199module_exit(adummy_cleanup);
200
201MODULE_AUTHOR("chas williams <chas@cmf.nrl.navy.mil>");
202MODULE_DESCRIPTION("dummy ATM driver");
203MODULE_LICENSE("GPL");
204