1/*
2 * Opticon USB barcode to serial driver
3 *
4 * Copyright (C) 2011 - 2012 Johan Hovold <jhovold@gmail.com>
5 * Copyright (C) 2011 Martin Jansen <martin.jansen@opticon.com>
6 * Copyright (C) 2008 - 2009 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (C) 2008 - 2009 Novell Inc.
8 *
9 *	This program is free software; you can redistribute it and/or
10 *	modify it under the terms of the GNU General Public License version
11 *	2 as published by the Free Software Foundation.
12 */
13
14#include <linux/kernel.h>
15#include <linux/tty.h>
16#include <linux/tty_driver.h>
17#include <linux/slab.h>
18#include <linux/tty_flip.h>
19#include <linux/serial.h>
20#include <linux/module.h>
21#include <linux/usb.h>
22#include <linux/usb/serial.h>
23#include <linux/uaccess.h>
24
25#define CONTROL_RTS			0x02
26#define RESEND_CTS_STATE	0x03
27
28/* max number of write urbs in flight */
29#define URB_UPPER_LIMIT	8
30
31/* This driver works for the Opticon 1D barcode reader
32 * an examples of 1D barcode types are EAN, UPC, Code39, IATA etc.. */
33#define DRIVER_DESC	"Opticon USB barcode to serial driver (1D)"
34
35static const struct usb_device_id id_table[] = {
36	{ USB_DEVICE(0x065a, 0x0009) },
37	{ },
38};
39MODULE_DEVICE_TABLE(usb, id_table);
40
41/* This structure holds all of the individual device information */
42struct opticon_private {
43	spinlock_t lock;	/* protects the following flags */
44	bool rts;
45	bool cts;
46	int outstanding_urbs;
47};
48
49
50static 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
57static 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
71static 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
102static 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, 0);
120	kfree(buffer);
121
122	if (retval < 0)
123		return retval;
124
125	return 0;
126}
127
128static 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
155static void opticon_write_control_callback(struct urb *urb)
156{
157	struct usb_serial_port *port = urb->context;
158	struct opticon_private *priv = usb_get_serial_port_data(port);
159	int status = urb->status;
160	unsigned long flags;
161
162	/* free up the transfer buffer, as usb_free_urb() does not do this */
163	kfree(urb->transfer_buffer);
164
165	/* setup packet may be set if we're using it for writing */
166	kfree(urb->setup_packet);
167
168	if (status)
169		dev_dbg(&port->dev,
170			"%s - non-zero urb status received: %d\n",
171			__func__, status);
172
173	spin_lock_irqsave(&priv->lock, flags);
174	--priv->outstanding_urbs;
175	spin_unlock_irqrestore(&priv->lock, flags);
176
177	usb_serial_port_softint(port);
178}
179
180static int opticon_write(struct tty_struct *tty, struct usb_serial_port *port,
181			 const unsigned char *buf, int count)
182{
183	struct opticon_private *priv = usb_get_serial_port_data(port);
184	struct usb_serial *serial = port->serial;
185	struct urb *urb;
186	unsigned char *buffer;
187	unsigned long flags;
188	int status;
189	struct usb_ctrlrequest *dr;
190
191	spin_lock_irqsave(&priv->lock, flags);
192	if (priv->outstanding_urbs > URB_UPPER_LIMIT) {
193		spin_unlock_irqrestore(&priv->lock, flags);
194		dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
195		return 0;
196	}
197	priv->outstanding_urbs++;
198	spin_unlock_irqrestore(&priv->lock, flags);
199
200	buffer = kmalloc(count, GFP_ATOMIC);
201	if (!buffer) {
202		count = -ENOMEM;
203		goto error_no_buffer;
204	}
205
206	urb = usb_alloc_urb(0, GFP_ATOMIC);
207	if (!urb) {
208		count = -ENOMEM;
209		goto error_no_urb;
210	}
211
212	memcpy(buffer, buf, count);
213
214	usb_serial_debug_data(&port->dev, __func__, count, buffer);
215
216	/* The connected devices do not have a bulk write endpoint,
217	 * to transmit data to de barcode device the control endpoint is used */
218	dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_ATOMIC);
219	if (!dr) {
220		count = -ENOMEM;
221		goto error_no_dr;
222	}
223
224	dr->bRequestType = USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT;
225	dr->bRequest = 0x01;
226	dr->wValue = 0;
227	dr->wIndex = 0;
228	dr->wLength = cpu_to_le16(count);
229
230	usb_fill_control_urb(urb, serial->dev,
231		usb_sndctrlpipe(serial->dev, 0),
232		(unsigned char *)dr, buffer, count,
233		opticon_write_control_callback, port);
234
235	/* send it down the pipe */
236	status = usb_submit_urb(urb, GFP_ATOMIC);
237	if (status) {
238		dev_err(&port->dev,
239		"%s - usb_submit_urb(write endpoint) failed status = %d\n",
240							__func__, status);
241		count = status;
242		goto error;
243	}
244
245	/* we are done with this urb, so let the host driver
246	 * really free it when it is finished with it */
247	usb_free_urb(urb);
248
249	return count;
250error:
251	kfree(dr);
252error_no_dr:
253	usb_free_urb(urb);
254error_no_urb:
255	kfree(buffer);
256error_no_buffer:
257	spin_lock_irqsave(&priv->lock, flags);
258	--priv->outstanding_urbs;
259	spin_unlock_irqrestore(&priv->lock, flags);
260	return count;
261}
262
263static int opticon_write_room(struct tty_struct *tty)
264{
265	struct usb_serial_port *port = tty->driver_data;
266	struct opticon_private *priv = usb_get_serial_port_data(port);
267	unsigned long flags;
268
269	/*
270	 * We really can take almost anything the user throws at us
271	 * but let's pick a nice big number to tell the tty
272	 * layer that we have lots of free space, unless we don't.
273	 */
274	spin_lock_irqsave(&priv->lock, flags);
275	if (priv->outstanding_urbs > URB_UPPER_LIMIT * 2 / 3) {
276		spin_unlock_irqrestore(&priv->lock, flags);
277		dev_dbg(&port->dev, "%s - write limit hit\n", __func__);
278		return 0;
279	}
280	spin_unlock_irqrestore(&priv->lock, flags);
281
282	return 2048;
283}
284
285static int opticon_tiocmget(struct tty_struct *tty)
286{
287	struct usb_serial_port *port = tty->driver_data;
288	struct opticon_private *priv = usb_get_serial_port_data(port);
289	unsigned long flags;
290	int result = 0;
291
292	spin_lock_irqsave(&priv->lock, flags);
293	if (priv->rts)
294		result |= TIOCM_RTS;
295	if (priv->cts)
296		result |= TIOCM_CTS;
297	spin_unlock_irqrestore(&priv->lock, flags);
298
299	dev_dbg(&port->dev, "%s - %x\n", __func__, result);
300	return result;
301}
302
303static int opticon_tiocmset(struct tty_struct *tty,
304			   unsigned int set, unsigned int clear)
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	bool rts;
310	bool changed = false;
311	int ret;
312
313	/* We only support RTS so we only handle that */
314	spin_lock_irqsave(&priv->lock, flags);
315
316	rts = priv->rts;
317	if (set & TIOCM_RTS)
318		priv->rts = true;
319	if (clear & TIOCM_RTS)
320		priv->rts = false;
321	changed = rts ^ priv->rts;
322	spin_unlock_irqrestore(&priv->lock, flags);
323
324	if (!changed)
325		return 0;
326
327	ret = send_control_msg(port, CONTROL_RTS, !rts);
328	if (ret)
329		return usb_translate_errors(ret);
330
331	return 0;
332}
333
334static int get_serial_info(struct usb_serial_port *port,
335			   struct serial_struct __user *serial)
336{
337	struct serial_struct tmp;
338
339	if (!serial)
340		return -EFAULT;
341
342	memset(&tmp, 0x00, sizeof(tmp));
343
344	/* fake emulate a 16550 uart to make userspace code happy */
345	tmp.type		= PORT_16550A;
346	tmp.line		= port->minor;
347	tmp.port		= 0;
348	tmp.irq			= 0;
349	tmp.flags		= ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
350	tmp.xmit_fifo_size	= 1024;
351	tmp.baud_base		= 9600;
352	tmp.close_delay		= 5*HZ;
353	tmp.closing_wait	= 30*HZ;
354
355	if (copy_to_user(serial, &tmp, sizeof(*serial)))
356		return -EFAULT;
357	return 0;
358}
359
360static int opticon_ioctl(struct tty_struct *tty,
361			 unsigned int cmd, unsigned long arg)
362{
363	struct usb_serial_port *port = tty->driver_data;
364
365	switch (cmd) {
366	case TIOCGSERIAL:
367		return get_serial_info(port,
368				       (struct serial_struct __user *)arg);
369	}
370
371	return -ENOIOCTLCMD;
372}
373
374static int opticon_startup(struct usb_serial *serial)
375{
376	if (!serial->num_bulk_in) {
377		dev_err(&serial->dev->dev, "no bulk in endpoint\n");
378		return -ENODEV;
379	}
380
381	return 0;
382}
383
384static int opticon_port_probe(struct usb_serial_port *port)
385{
386	struct opticon_private *priv;
387
388	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
389	if (!priv)
390		return -ENOMEM;
391
392	spin_lock_init(&priv->lock);
393
394	usb_set_serial_port_data(port, priv);
395
396	return 0;
397}
398
399static int opticon_port_remove(struct usb_serial_port *port)
400{
401	struct opticon_private *priv = usb_get_serial_port_data(port);
402
403	kfree(priv);
404
405	return 0;
406}
407
408static struct usb_serial_driver opticon_device = {
409	.driver = {
410		.owner =	THIS_MODULE,
411		.name =		"opticon",
412	},
413	.id_table =		id_table,
414	.num_ports =		1,
415	.bulk_in_size =		256,
416	.attach =		opticon_startup,
417	.port_probe =		opticon_port_probe,
418	.port_remove =		opticon_port_remove,
419	.open =			opticon_open,
420	.write =		opticon_write,
421	.write_room = 		opticon_write_room,
422	.throttle =		usb_serial_generic_throttle,
423	.unthrottle =		usb_serial_generic_unthrottle,
424	.ioctl =		opticon_ioctl,
425	.tiocmget =		opticon_tiocmget,
426	.tiocmset =		opticon_tiocmset,
427	.process_read_urb =	opticon_process_read_urb,
428};
429
430static struct usb_serial_driver * const serial_drivers[] = {
431	&opticon_device, NULL
432};
433
434module_usb_serial_driver(serial_drivers, id_table);
435
436MODULE_DESCRIPTION(DRIVER_DESC);
437MODULE_LICENSE("GPL");
438