1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 *  Copyright (c) 2000-2001 Vojtech Pavlik <vojtech@ucw.cz>
4 *  Copyright (c) 2001, 2007 Johann Deneux <johann.deneux@gmail.com>
5 *
6 *  USB/RS232 I-Force joysticks and wheels.
7 */
8
9#include <linux/serio.h>
10#include "iforce.h"
11
12struct iforce_serio {
13	struct iforce iforce;
14
15	struct serio *serio;
16	int idx, pkt, len, id;
17	u8 csum;
18	u8 expect_packet;
19	u8 cmd_response[IFORCE_MAX_LENGTH];
20	u8 cmd_response_len;
21	u8 data_in[IFORCE_MAX_LENGTH];
22};
23
24static void iforce_serio_xmit(struct iforce *iforce)
25{
26	struct iforce_serio *iforce_serio = container_of(iforce,
27							 struct iforce_serio,
28							 iforce);
29	unsigned char cs;
30	int i;
31	unsigned long flags;
32
33	if (test_and_set_bit(IFORCE_XMIT_RUNNING, iforce->xmit_flags)) {
34		set_bit(IFORCE_XMIT_AGAIN, iforce->xmit_flags);
35		return;
36	}
37
38	spin_lock_irqsave(&iforce->xmit_lock, flags);
39
40again:
41	if (iforce->xmit.head == iforce->xmit.tail) {
42		iforce_clear_xmit_and_wake(iforce);
43		spin_unlock_irqrestore(&iforce->xmit_lock, flags);
44		return;
45	}
46
47	cs = 0x2b;
48
49	serio_write(iforce_serio->serio, 0x2b);
50
51	serio_write(iforce_serio->serio, iforce->xmit.buf[iforce->xmit.tail]);
52	cs ^= iforce->xmit.buf[iforce->xmit.tail];
53	XMIT_INC(iforce->xmit.tail, 1);
54
55	for (i=iforce->xmit.buf[iforce->xmit.tail]; i >= 0; --i) {
56		serio_write(iforce_serio->serio,
57			    iforce->xmit.buf[iforce->xmit.tail]);
58		cs ^= iforce->xmit.buf[iforce->xmit.tail];
59		XMIT_INC(iforce->xmit.tail, 1);
60	}
61
62	serio_write(iforce_serio->serio, cs);
63
64	if (test_and_clear_bit(IFORCE_XMIT_AGAIN, iforce->xmit_flags))
65		goto again;
66
67	iforce_clear_xmit_and_wake(iforce);
68
69	spin_unlock_irqrestore(&iforce->xmit_lock, flags);
70}
71
72static int iforce_serio_get_id(struct iforce *iforce, u8 id,
73			       u8 *response_data, size_t *response_len)
74{
75	struct iforce_serio *iforce_serio = container_of(iforce,
76							 struct iforce_serio,
77							 iforce);
78
79	iforce_serio->expect_packet = HI(FF_CMD_QUERY);
80	iforce_serio->cmd_response_len = 0;
81
82	iforce_send_packet(iforce, FF_CMD_QUERY, &id);
83
84	wait_event_interruptible_timeout(iforce->wait,
85					 !iforce_serio->expect_packet, HZ);
86
87	if (iforce_serio->expect_packet) {
88		iforce_serio->expect_packet = 0;
89		return -ETIMEDOUT;
90	}
91
92	if (iforce_serio->cmd_response[0] != id)
93		return -EIO;
94
95	memcpy(response_data, iforce_serio->cmd_response,
96	       iforce_serio->cmd_response_len);
97	*response_len = iforce_serio->cmd_response_len;
98
99	return 0;
100}
101
102static int iforce_serio_start_io(struct iforce *iforce)
103{
104	/* No special handling required */
105	return 0;
106}
107
108static void iforce_serio_stop_io(struct iforce *iforce)
109{
110	//TODO: Wait for the last packets to be sent
111}
112
113static const struct iforce_xport_ops iforce_serio_xport_ops = {
114	.xmit		= iforce_serio_xmit,
115	.get_id		= iforce_serio_get_id,
116	.start_io	= iforce_serio_start_io,
117	.stop_io	= iforce_serio_stop_io,
118};
119
120static void iforce_serio_write_wakeup(struct serio *serio)
121{
122	struct iforce *iforce = serio_get_drvdata(serio);
123
124	iforce_serio_xmit(iforce);
125}
126
127static irqreturn_t iforce_serio_irq(struct serio *serio,
128				    unsigned char data, unsigned int flags)
129{
130	struct iforce_serio *iforce_serio = serio_get_drvdata(serio);
131	struct iforce *iforce = &iforce_serio->iforce;
132
133	if (!iforce_serio->pkt) {
134		if (data == 0x2b)
135			iforce_serio->pkt = 1;
136		goto out;
137	}
138
139	if (!iforce_serio->id) {
140		if (data > 3 && data != 0xff)
141			iforce_serio->pkt = 0;
142		else
143			iforce_serio->id = data;
144		goto out;
145	}
146
147	if (!iforce_serio->len) {
148		if (data > IFORCE_MAX_LENGTH) {
149			iforce_serio->pkt = 0;
150			iforce_serio->id = 0;
151		} else {
152			iforce_serio->len = data;
153		}
154		goto out;
155	}
156
157	if (iforce_serio->idx < iforce_serio->len) {
158		iforce_serio->data_in[iforce_serio->idx++] = data;
159		iforce_serio->csum += data;
160		goto out;
161	}
162
163	if (iforce_serio->idx == iforce_serio->len) {
164		/* Handle command completion */
165		if (iforce_serio->expect_packet == iforce_serio->id) {
166			iforce_serio->expect_packet = 0;
167			memcpy(iforce_serio->cmd_response,
168			       iforce_serio->data_in, IFORCE_MAX_LENGTH);
169			iforce_serio->cmd_response_len = iforce_serio->len;
170
171			/* Signal that command is done */
172			wake_up_all(&iforce->wait);
173		} else if (likely(iforce->type)) {
174			iforce_process_packet(iforce, iforce_serio->id,
175					      iforce_serio->data_in,
176					      iforce_serio->len);
177		}
178
179		iforce_serio->pkt = 0;
180		iforce_serio->id  = 0;
181		iforce_serio->len = 0;
182		iforce_serio->idx = 0;
183		iforce_serio->csum = 0;
184	}
185out:
186	return IRQ_HANDLED;
187}
188
189static int iforce_serio_connect(struct serio *serio, struct serio_driver *drv)
190{
191	struct iforce_serio *iforce_serio;
192	int err;
193
194	iforce_serio = kzalloc(sizeof(*iforce_serio), GFP_KERNEL);
195	if (!iforce_serio)
196		return -ENOMEM;
197
198	iforce_serio->iforce.xport_ops = &iforce_serio_xport_ops;
199
200	iforce_serio->serio = serio;
201	serio_set_drvdata(serio, iforce_serio);
202
203	err = serio_open(serio, drv);
204	if (err)
205		goto fail1;
206
207	err = iforce_init_device(&serio->dev, BUS_RS232, &iforce_serio->iforce);
208	if (err)
209		goto fail2;
210
211	return 0;
212
213 fail2:	serio_close(serio);
214 fail1:	serio_set_drvdata(serio, NULL);
215	kfree(iforce_serio);
216	return err;
217}
218
219static void iforce_serio_disconnect(struct serio *serio)
220{
221	struct iforce_serio *iforce_serio = serio_get_drvdata(serio);
222
223	input_unregister_device(iforce_serio->iforce.dev);
224	serio_close(serio);
225	serio_set_drvdata(serio, NULL);
226	kfree(iforce_serio);
227}
228
229static const struct serio_device_id iforce_serio_ids[] = {
230	{
231		.type	= SERIO_RS232,
232		.proto	= SERIO_IFORCE,
233		.id	= SERIO_ANY,
234		.extra	= SERIO_ANY,
235	},
236	{ 0 }
237};
238
239MODULE_DEVICE_TABLE(serio, iforce_serio_ids);
240
241struct serio_driver iforce_serio_drv = {
242	.driver		= {
243		.name	= "iforce",
244	},
245	.description	= "RS232 I-Force joysticks and wheels driver",
246	.id_table	= iforce_serio_ids,
247	.write_wakeup	= iforce_serio_write_wakeup,
248	.interrupt	= iforce_serio_irq,
249	.connect	= iforce_serio_connect,
250	.disconnect	= iforce_serio_disconnect,
251};
252
253module_serio_driver(iforce_serio_drv);
254
255MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>, Johann Deneux <johann.deneux@gmail.com>");
256MODULE_DESCRIPTION("RS232 I-Force joysticks and wheels driver");
257MODULE_LICENSE("GPL");
258