1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Symbol USB barcode to serial driver
4 *
5 * Copyright (C) 2013 Johan Hovold <jhovold@gmail.com>
6 * Copyright (C) 2009 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (C) 2009 Novell Inc.
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/tty.h>
12 #include <linux/slab.h>
13 #include <linux/tty_driver.h>
14 #include <linux/tty_flip.h>
15 #include <linux/module.h>
16 #include <linux/usb.h>
17 #include <linux/usb/serial.h>
18 #include <linux/uaccess.h>
19
20 static const struct usb_device_id id_table[] = {
21 { USB_DEVICE(0x05e0, 0x0600) },
22 { },
23 };
24 MODULE_DEVICE_TABLE(usb, id_table);
25
26 struct symbol_private {
27 spinlock_t lock; /* protects the following flags */
28 bool throttled;
29 bool actually_throttled;
30 };
31
symbol_int_callback(struct urb * urb)32 static void symbol_int_callback(struct urb *urb)
33 {
34 struct usb_serial_port *port = urb->context;
35 struct symbol_private *priv = usb_get_serial_port_data(port);
36 unsigned char *data = urb->transfer_buffer;
37 int status = urb->status;
38 unsigned long flags;
39 int result;
40 int data_length;
41
42 switch (status) {
43 case 0:
44 /* success */
45 break;
46 case -ECONNRESET:
47 case -ENOENT:
48 case -ESHUTDOWN:
49 /* this urb is terminated, clean up */
50 dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
51 __func__, status);
52 return;
53 default:
54 dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
55 __func__, status);
56 goto exit;
57 }
58
59 usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
60
61 /*
62 * Data from the device comes with a 1 byte header:
63 *
64 * <size of data> <data>...
65 */
66 if (urb->actual_length > 1) {
67 data_length = data[0];
68 if (data_length > (urb->actual_length - 1))
69 data_length = urb->actual_length - 1;
70 tty_insert_flip_string(&port->port, &data[1], data_length);
71 tty_flip_buffer_push(&port->port);
72 } else {
73 dev_dbg(&port->dev, "%s - short packet\n", __func__);
74 }
75
76 exit:
77 spin_lock_irqsave(&priv->lock, flags);
78
79 /* Continue trying to always read if we should */
80 if (!priv->throttled) {
81 result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
82 if (result)
83 dev_err(&port->dev,
84 "%s - failed resubmitting read urb, error %d\n",
85 __func__, result);
86 } else
87 priv->actually_throttled = true;
88 spin_unlock_irqrestore(&priv->lock, flags);
89 }
90
symbol_open(struct tty_struct * tty,struct usb_serial_port * port)91 static int symbol_open(struct tty_struct *tty, struct usb_serial_port *port)
92 {
93 struct symbol_private *priv = usb_get_serial_port_data(port);
94 unsigned long flags;
95 int result = 0;
96
97 spin_lock_irqsave(&priv->lock, flags);
98 priv->throttled = false;
99 priv->actually_throttled = false;
100 spin_unlock_irqrestore(&priv->lock, flags);
101
102 /* Start reading from the device */
103 result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
104 if (result)
105 dev_err(&port->dev,
106 "%s - failed resubmitting read urb, error %d\n",
107 __func__, result);
108 return result;
109 }
110
symbol_close(struct usb_serial_port * port)111 static void symbol_close(struct usb_serial_port *port)
112 {
113 usb_kill_urb(port->interrupt_in_urb);
114 }
115
symbol_throttle(struct tty_struct * tty)116 static void symbol_throttle(struct tty_struct *tty)
117 {
118 struct usb_serial_port *port = tty->driver_data;
119 struct symbol_private *priv = usb_get_serial_port_data(port);
120
121 spin_lock_irq(&priv->lock);
122 priv->throttled = true;
123 spin_unlock_irq(&priv->lock);
124 }
125
symbol_unthrottle(struct tty_struct * tty)126 static void symbol_unthrottle(struct tty_struct *tty)
127 {
128 struct usb_serial_port *port = tty->driver_data;
129 struct symbol_private *priv = usb_get_serial_port_data(port);
130 int result;
131 bool was_throttled;
132
133 spin_lock_irq(&priv->lock);
134 priv->throttled = false;
135 was_throttled = priv->actually_throttled;
136 priv->actually_throttled = false;
137 spin_unlock_irq(&priv->lock);
138
139 if (was_throttled) {
140 result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
141 if (result)
142 dev_err(&port->dev,
143 "%s - failed submitting read urb, error %d\n",
144 __func__, result);
145 }
146 }
147
symbol_port_probe(struct usb_serial_port * port)148 static int symbol_port_probe(struct usb_serial_port *port)
149 {
150 struct symbol_private *priv;
151
152 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
153 if (!priv)
154 return -ENOMEM;
155
156 spin_lock_init(&priv->lock);
157
158 usb_set_serial_port_data(port, priv);
159
160 return 0;
161 }
162
symbol_port_remove(struct usb_serial_port * port)163 static void symbol_port_remove(struct usb_serial_port *port)
164 {
165 struct symbol_private *priv = usb_get_serial_port_data(port);
166
167 kfree(priv);
168 }
169
170 static struct usb_serial_driver symbol_device = {
171 .driver = {
172 .owner = THIS_MODULE,
173 .name = "symbol",
174 },
175 .id_table = id_table,
176 .num_ports = 1,
177 .num_interrupt_in = 1,
178 .port_probe = symbol_port_probe,
179 .port_remove = symbol_port_remove,
180 .open = symbol_open,
181 .close = symbol_close,
182 .throttle = symbol_throttle,
183 .unthrottle = symbol_unthrottle,
184 .read_int_callback = symbol_int_callback,
185 };
186
187 static struct usb_serial_driver * const serial_drivers[] = {
188 &symbol_device, NULL
189 };
190
191 module_usb_serial_driver(serial_drivers, id_table);
192
193 MODULE_LICENSE("GPL v2");
194