1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Opticon USB barcode to serial driver
4 *
5 * Copyright (C) 2011 - 2012 Johan Hovold <jhovold@gmail.com>
6 * Copyright (C) 2011 Martin Jansen <martin.jansen@opticon.com>
7 * Copyright (C) 2008 - 2009 Greg Kroah-Hartman <gregkh@suse.de>
8 * Copyright (C) 2008 - 2009 Novell Inc.
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/tty.h>
13 #include <linux/tty_driver.h>
14 #include <linux/slab.h>
15 #include <linux/tty_flip.h>
16 #include <linux/serial.h>
17 #include <linux/module.h>
18 #include <linux/usb.h>
19 #include <linux/usb/serial.h>
20 #include <linux/uaccess.h>
21
22 #define CONTROL_RTS 0x02
23 #define RESEND_CTS_STATE 0x03
24
25 /* max number of write urbs in flight */
26 #define URB_UPPER_LIMIT 8
27
28 /* This driver works for the Opticon 1D barcode reader
29 * an examples of 1D barcode types are EAN, UPC, Code39, IATA etc.. */
30 #define DRIVER_DESC "Opticon USB barcode to serial driver (1D)"
31
32 static const struct usb_device_id id_table[] = {
33 { USB_DEVICE(0x065a, 0x0009) },
34 { },
35 };
36 MODULE_DEVICE_TABLE(usb, id_table);
37
38 /* This structure holds all of the individual device information */
39 struct opticon_private {
40 spinlock_t lock; /* protects the following flags */
41 bool rts;
42 bool cts;
43 int outstanding_urbs;
44 int outstanding_bytes;
45
46 struct usb_anchor anchor;
47 };
48
49
opticon_process_data_packet(struct usb_serial_port * port,const unsigned char * buf,size_t len)50 static void opticon_process_data_packet(struct usb_serial_port *port,
51 const unsigned char *buf, size_t len)
52 {
53 tty_insert_flip_string(&port->port, buf, len);
54 tty_flip_buffer_push(&port->port);
55 }
56
opticon_process_status_packet(struct usb_serial_port * port,const unsigned char * buf,size_t len)57 static void opticon_process_status_packet(struct usb_serial_port *port,
58 const unsigned char *buf, size_t len)
59 {
60 struct opticon_private *priv = usb_get_serial_port_data(port);
61 unsigned long flags;
62
63 spin_lock_irqsave(&priv->lock, flags);
64 if (buf[0] == 0x00)
65 priv->cts = false;
66 else
67 priv->cts = true;
68 spin_unlock_irqrestore(&priv->lock, flags);
69 }
70
opticon_process_read_urb(struct urb * urb)71 static void opticon_process_read_urb(struct urb *urb)
72 {
73 struct usb_serial_port *port = urb->context;
74 const unsigned char *hdr = urb->transfer_buffer;
75 const unsigned char *data = hdr + 2;
76 size_t data_len = urb->actual_length - 2;
77
78 if (urb->actual_length <= 2) {
79 dev_dbg(&port->dev, "malformed packet received: %d bytes\n",
80 urb->actual_length);
81 return;
82 }
83 /*
84 * Data from the device comes with a 2 byte header:
85 *
86 * <0x00><0x00>data...
87 * This is real data to be sent to the tty layer
88 * <0x00><0x01>level
89 * This is a CTS level change, the third byte is the CTS
90 * value (0 for low, 1 for high).
91 */
92 if ((hdr[0] == 0x00) && (hdr[1] == 0x00)) {
93 opticon_process_data_packet(port, data, data_len);
94 } else if ((hdr[0] == 0x00) && (hdr[1] == 0x01)) {
95 opticon_process_status_packet(port, data, data_len);
96 } else {
97 dev_dbg(&port->dev, "unknown packet received: %02x %02x\n",
98 hdr[0], hdr[1]);
99 }
100 }
101
send_control_msg(struct usb_serial_port * port,u8 requesttype,u8 val)102 static int send_control_msg(struct usb_serial_port *port, u8 requesttype,
103 u8 val)
104 {
105 struct usb_serial *serial = port->serial;
106 int retval;
107 u8 *buffer;
108
109 buffer = kzalloc(1, GFP_KERNEL);
110 if (!buffer)
111 return -ENOMEM;
112
113 buffer[0] = val;
114 /* Send the message to the vendor control endpoint
115 * of the connected device */
116 retval = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
117 requesttype,
118 USB_DIR_OUT|USB_TYPE_VENDOR|USB_RECIP_INTERFACE,
119 0, 0, buffer, 1, USB_CTRL_SET_TIMEOUT);
120 kfree(buffer);
121
122 if (retval < 0)
123 return retval;
124
125 return 0;
126 }
127
opticon_open(struct tty_struct * tty,struct usb_serial_port * port)128 static int opticon_open(struct tty_struct *tty, struct usb_serial_port *port)
129 {
130 struct opticon_private *priv = usb_get_serial_port_data(port);
131 unsigned long flags;
132 int res;
133
134 spin_lock_irqsave(&priv->lock, flags);
135 priv->rts = false;
136 spin_unlock_irqrestore(&priv->lock, flags);
137
138 /* Clear RTS line */
139 send_control_msg(port, CONTROL_RTS, 0);
140
141 /* clear the halt status of the endpoint */
142 usb_clear_halt(port->serial->dev, port->read_urb->pipe);
143
144 res = usb_serial_generic_open(tty, port);
145 if (res)
146 return res;
147
148 /* Request CTS line state, sometimes during opening the current
149 * CTS state can be missed. */
150 send_control_msg(port, RESEND_CTS_STATE, 1);
151
152 return res;
153 }
154
opticon_close(struct usb_serial_port * port)155 static void opticon_close(struct usb_serial_port *port)
156 {
157 struct opticon_private *priv = usb_get_serial_port_data(port);
158
159 usb_kill_anchored_urbs(&priv->anchor);
160
161 usb_serial_generic_close(port);
162 }
163
opticon_write_control_callback(struct urb * urb)164 static void opticon_write_control_callback(struct urb *urb)
165 {
166 struct usb_serial_port *port = urb->context;
167 struct opticon_private *priv = usb_get_serial_port_data(port);
168 int status = urb->status;
169 unsigned long flags;
170
171 /* free up the transfer buffer, as usb_free_urb() does not do this */
172 kfree(urb->transfer_buffer);
173
174 /* setup packet may be set if we're using it for writing */
175 kfree(urb->setup_packet);
176
177 if (status)
178 dev_dbg(&port->dev,
179 "%s - non-zero urb status received: %d\n",
180 __func__, status);
181
182 spin_lock_irqsave(&priv->lock, flags);
183 --priv->outstanding_urbs;
184 priv->outstanding_bytes -= urb->transfer_buffer_length;
185 spin_unlock_irqrestore(&priv->lock, flags);
186
187 usb_serial_port_softint(port);
188 }
189
opticon_write(struct tty_struct * tty,struct usb_serial_port * port,const unsigned char * buf,int count)190 static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
191 const unsigned char *buf, int count)
192 {
193 struct opticon_private *priv = usb_get_serial_port_data(port);
194 struct usb_serial *serial = port->serial;
195 struct urb *urb;
196 unsigned char *buffer;
197 unsigned long flags;
198 struct usb_ctrlrequest *dr;
199 int ret = -ENOMEM;
200
201 spin_lock_irqsave(&priv->lock, flags);
202 if (priv->outstanding_urbs > URB_UPPER_LIMIT) {
203 spin_unlock_irqrestore(&priv->lock, flags);
204 dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
205 return 0;
206 }
207 priv->outstanding_urbs++;
208 priv->outstanding_bytes += count;
209 spin_unlock_irqrestore(&priv->lock, flags);
210
211 buffer = kmemdup(buf, count, GFP_ATOMIC);
212 if (!buffer)
213 goto error_no_buffer;
214
215 urb = usb_alloc_urb(0, GFP_ATOMIC);
216 if (!urb)
217 goto error_no_urb;
218
219 usb_serial_debug_data(&port->dev, __func__, count, buffer);
220
221 /* The connected devices do not have a bulk write endpoint,
222 * to transmit data to de barcode device the control endpoint is used */
223 dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
224 if (!dr)
225 goto error_no_dr;
226
227 dr->bRequestType = USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT;
228 dr->bRequest = 0x01;
229 dr->wValue = 0;
230 dr->wIndex = 0;
231 dr->wLength = cpu_to_le16(count);
232
233 usb_fill_control_urb(urb, serial->dev,
234 usb_sndctrlpipe(serial->dev, 0),
235 (unsigned char *)dr, buffer, count,
236 opticon_write_control_callback, port);
237
238 usb_anchor_urb(urb, &priv->anchor);
239
240 /* send it down the pipe */
241 ret = usb_submit_urb(urb, GFP_ATOMIC);
242 if (ret) {
243 dev_err(&port->dev, "failed to submit write urb: %d\n", ret);
244 usb_unanchor_urb(urb);
245 goto error;
246 }
247
248 /* we are done with this urb, so let the host driver
249 * really free it when it is finished with it */
250 usb_free_urb(urb);
251
252 return count;
253 error:
254 kfree(dr);
255 error_no_dr:
256 usb_free_urb(urb);
257 error_no_urb:
258 kfree(buffer);
259 error_no_buffer:
260 spin_lock_irqsave(&priv->lock, flags);
261 --priv->outstanding_urbs;
262 priv->outstanding_bytes -= count;
263 spin_unlock_irqrestore(&priv->lock, flags);
264
265 return ret;
266 }
267
opticon_write_room(struct tty_struct * tty)268 static unsigned int opticon_write_room(struct tty_struct *tty)
269 {
270 struct usb_serial_port *port = tty->driver_data;
271 struct opticon_private *priv = usb_get_serial_port_data(port);
272 unsigned long flags;
273
274 /*
275 * We really can take almost anything the user throws at us
276 * but let's pick a nice big number to tell the tty
277 * layer that we have lots of free space, unless we don't.
278 */
279 spin_lock_irqsave(&priv->lock, flags);
280 if (priv->outstanding_urbs > URB_UPPER_LIMIT * 2 / 3) {
281 spin_unlock_irqrestore(&priv->lock, flags);
282 dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
283 return 0;
284 }
285 spin_unlock_irqrestore(&priv->lock, flags);
286
287 return 2048;
288 }
289
opticon_chars_in_buffer(struct tty_struct * tty)290 static unsigned int opticon_chars_in_buffer(struct tty_struct *tty)
291 {
292 struct usb_serial_port *port = tty->driver_data;
293 struct opticon_private *priv = usb_get_serial_port_data(port);
294 unsigned long flags;
295 unsigned int count;
296
297 spin_lock_irqsave(&priv->lock, flags);
298 count = priv->outstanding_bytes;
299 spin_unlock_irqrestore(&priv->lock, flags);
300
301 return count;
302 }
303
opticon_tiocmget(struct tty_struct * tty)304 static int opticon_tiocmget(struct tty_struct *tty)
305 {
306 struct usb_serial_port *port = tty->driver_data;
307 struct opticon_private *priv = usb_get_serial_port_data(port);
308 unsigned long flags;
309 int result = 0;
310
311 spin_lock_irqsave(&priv->lock, flags);
312 if (priv->rts)
313 result |= TIOCM_RTS;
314 if (priv->cts)
315 result |= TIOCM_CTS;
316 spin_unlock_irqrestore(&priv->lock, flags);
317
318 dev_dbg(&port->dev, "%s - %x\n", __func__, result);
319 return result;
320 }
321
opticon_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)322 static int opticon_tiocmset(struct tty_struct *tty,
323 unsigned int set, unsigned int clear)
324 {
325 struct usb_serial_port *port = tty->driver_data;
326 struct opticon_private *priv = usb_get_serial_port_data(port);
327 unsigned long flags;
328 bool rts;
329 bool changed = false;
330 int ret;
331
332 /* We only support RTS so we only handle that */
333 spin_lock_irqsave(&priv->lock, flags);
334
335 rts = priv->rts;
336 if (set & TIOCM_RTS)
337 priv->rts = true;
338 if (clear & TIOCM_RTS)
339 priv->rts = false;
340 changed = rts ^ priv->rts;
341 spin_unlock_irqrestore(&priv->lock, flags);
342
343 if (!changed)
344 return 0;
345
346 ret = send_control_msg(port, CONTROL_RTS, !rts);
347 if (ret)
348 return usb_translate_errors(ret);
349
350 return 0;
351 }
352
opticon_port_probe(struct usb_serial_port * port)353 static int opticon_port_probe(struct usb_serial_port *port)
354 {
355 struct opticon_private *priv;
356
357 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
358 if (!priv)
359 return -ENOMEM;
360
361 spin_lock_init(&priv->lock);
362 init_usb_anchor(&priv->anchor);
363
364 usb_set_serial_port_data(port, priv);
365
366 return 0;
367 }
368
opticon_port_remove(struct usb_serial_port * port)369 static void opticon_port_remove(struct usb_serial_port *port)
370 {
371 struct opticon_private *priv = usb_get_serial_port_data(port);
372
373 kfree(priv);
374 }
375
376 static struct usb_serial_driver opticon_device = {
377 .driver = {
378 .owner = THIS_MODULE,
379 .name = "opticon",
380 },
381 .id_table = id_table,
382 .num_ports = 1,
383 .num_bulk_in = 1,
384 .bulk_in_size = 256,
385 .port_probe = opticon_port_probe,
386 .port_remove = opticon_port_remove,
387 .open = opticon_open,
388 .close = opticon_close,
389 .write = opticon_write,
390 .write_room = opticon_write_room,
391 .chars_in_buffer = opticon_chars_in_buffer,
392 .throttle = usb_serial_generic_throttle,
393 .unthrottle = usb_serial_generic_unthrottle,
394 .tiocmget = opticon_tiocmget,
395 .tiocmset = opticon_tiocmset,
396 .process_read_urb = opticon_process_read_urb,
397 };
398
399 static struct usb_serial_driver * const serial_drivers[] = {
400 &opticon_device, NULL
401 };
402
403 module_usb_serial_driver(serial_drivers, id_table);
404
405 MODULE_DESCRIPTION(DRIVER_DESC);
406 MODULE_LICENSE("GPL v2");
407