iforce-serio.c

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