summaryrefslogtreecommitdiffstats
path: root/drivers/tty/serial/msm_smd_tty.c
blob: b43b4ec3926907010b01e03b40e49897fb5e26b0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
/*
 * Copyright (C) 2007 Google, Inc.
 * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
 * Author: Brian Swetland <swetland@google.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/wait.h>

#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>

#include <mach/msm_smd.h>

#define MAX_SMD_TTYS 32

struct smd_tty_info {
	struct tty_port port;
	smd_channel_t *ch;
};

struct smd_tty_channel_desc {
	int id;
	const char *name;
};

static struct smd_tty_info smd_tty[MAX_SMD_TTYS];

static const struct smd_tty_channel_desc smd_default_tty_channels[] = {
	{ .id = 0, .name = "SMD_DS" },
	{ .id = 27, .name = "SMD_GPSNMEA" },
};

static const struct smd_tty_channel_desc *smd_tty_channels =
		smd_default_tty_channels;
static int smd_tty_channels_len = ARRAY_SIZE(smd_default_tty_channels);

static void smd_tty_notify(void *priv, unsigned event)
{
	unsigned char *ptr;
	int avail;
	struct smd_tty_info *info = priv;
	struct tty_struct *tty;

	if (event != SMD_EVENT_DATA)
		return;

	tty = tty_port_tty_get(&info->port);
	if (!tty)
		return;

	for (;;) {
		if (test_bit(TTY_THROTTLED, &tty->flags))
			break;
		avail = smd_read_avail(info->ch);
		if (avail == 0)
			break;

		avail = tty_prepare_flip_string(&info->port, &ptr, avail);

		if (smd_read(info->ch, ptr, avail) != avail) {
			/* shouldn't be possible since we're in interrupt
			** context here and nobody else could 'steal' our
			** characters.
			*/
			pr_err("OOPS - smd_tty_buffer mismatch?!");
		}

		tty_flip_buffer_push(tty);
	}

	/* XXX only when writable and necessary */
	tty_wakeup(tty);
	tty_kref_put(tty);
}

static int smd_tty_port_activate(struct tty_port *tport, struct tty_struct *tty)
{
	int i, res = 0;
	int n = tty->index;
	const char *name = NULL;
	struct smd_tty_info *info = smd_tty + n;

	for (i = 0; i < smd_tty_channels_len; i++) {
		if (smd_tty_channels[i].id == n) {
			name = smd_tty_channels[i].name;
			break;
		}
	}
	if (!name)
		return -ENODEV;

	if (info->ch)
		smd_kick(info->ch);
	else
		res = smd_open(name, &info->ch, info, smd_tty_notify);

	if (!res)
		tty->driver_data = info;

	return res;
}

static void smd_tty_port_shutdown(struct tty_port *tport)
{
	struct smd_tty_info *info;
	struct tty_struct *tty = tty_port_tty_get(tport);

	info = tty->driver_data;
	if (info->ch) {
		smd_close(info->ch);
		info->ch = 0;
	}

	tty->driver_data = 0;
	tty_kref_put(tty);
}

static int smd_tty_open(struct tty_struct *tty, struct file *f)
{
	struct smd_tty_info *info = smd_tty + tty->index;

	return tty_port_open(&info->port, tty, f);
}

static void smd_tty_close(struct tty_struct *tty, struct file *f)
{
	struct smd_tty_info *info = tty->driver_data;

	tty_port_close(&info->port, tty, f);
}

static int smd_tty_write(struct tty_struct *tty,
			 const unsigned char *buf, int len)
{
	struct smd_tty_info *info = tty->driver_data;
	int avail;

	/* if we're writing to a packet channel we will
	** never be able to write more data than there
	** is currently space for
	*/
	avail = smd_write_avail(info->ch);
	if (len > avail)
		len = avail;

	return smd_write(info->ch, buf, len);
}

static int smd_tty_write_room(struct tty_struct *tty)
{
	struct smd_tty_info *info = tty->driver_data;
	return smd_write_avail(info->ch);
}

static int smd_tty_chars_in_buffer(struct tty_struct *tty)
{
	struct smd_tty_info *info = tty->driver_data;
	return smd_read_avail(info->ch);
}

static void smd_tty_unthrottle(struct tty_struct *tty)
{
	struct smd_tty_info *info = tty->driver_data;
	smd_kick(info->ch);
}

static const struct tty_port_operations smd_tty_port_ops = {
	.shutdown = smd_tty_port_shutdown,
	.activate = smd_tty_port_activate,
};

static const struct tty_operations smd_tty_ops = {
	.open = smd_tty_open,
	.close = smd_tty_close,
	.write = smd_tty_write,
	.write_room = smd_tty_write_room,
	.chars_in_buffer = smd_tty_chars_in_buffer,
	.unthrottle = smd_tty_unthrottle,
};

static struct tty_driver *smd_tty_driver;

static int __init smd_tty_init(void)
{
	int ret, i;

	smd_tty_driver = alloc_tty_driver(MAX_SMD_TTYS);
	if (smd_tty_driver == 0)
		return -ENOMEM;

	smd_tty_driver->driver_name = "smd_tty_driver";
	smd_tty_driver->name = "smd";
	smd_tty_driver->major = 0;
	smd_tty_driver->minor_start = 0;
	smd_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
	smd_tty_driver->subtype = SERIAL_TYPE_NORMAL;
	smd_tty_driver->init_termios = tty_std_termios;
	smd_tty_driver->init_termios.c_iflag = 0;
	smd_tty_driver->init_termios.c_oflag = 0;
	smd_tty_driver->init_termios.c_cflag = B38400 | CS8 | CREAD;
	smd_tty_driver->init_termios.c_lflag = 0;
	smd_tty_driver->flags = TTY_DRIVER_RESET_TERMIOS |
		TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
	tty_set_operations(smd_tty_driver, &smd_tty_ops);

	ret = tty_register_driver(smd_tty_driver);
	if (ret)
		return ret;

	for (i = 0; i < smd_tty_channels_len; i++) {
		struct tty_port *port = &smd_tty[smd_tty_channels[i].id].port;
		tty_port_init(port);
		port->ops = &smd_tty_port_ops;
		tty_port_register_device(port, smd_tty_driver,
				smd_tty_channels[i].id, NULL);
	}

	return 0;
}

module_init(smd_tty_init);