1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2012 GCT Semiconductor, Inc. All rights reserved. */
3
4 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
5
6 #include <linux/kernel.h>
7 #include <linux/errno.h>
8 #include <linux/tty.h>
9 #include <linux/tty_driver.h>
10 #include <linux/tty_flip.h>
11 #include <linux/module.h>
12 #include <linux/slab.h>
13 #include <linux/usb/cdc.h>
14 #include <linux/serial.h>
15 #include "gdm_tty.h"
16
17 #define GDM_TTY_MAJOR 0
18 #define GDM_TTY_MINOR 32
19
20 #define WRITE_SIZE 2048
21
22 #define MUX_TX_MAX_SIZE 2048
23
gdm_tty_ready(struct gdm * gdm)24 static inline bool gdm_tty_ready(struct gdm *gdm)
25 {
26 return gdm && gdm->tty_dev && gdm->port.count;
27 }
28
29 static struct tty_driver *gdm_driver[TTY_MAX_COUNT];
30 static struct gdm *gdm_table[TTY_MAX_COUNT][GDM_TTY_MINOR];
31 static DEFINE_MUTEX(gdm_table_lock);
32
33 static const char *DRIVER_STRING[TTY_MAX_COUNT] = {"GCTATC", "GCTDM"};
34 static char *DEVICE_STRING[TTY_MAX_COUNT] = {"GCT-ATC", "GCT-DM"};
35
gdm_port_destruct(struct tty_port * port)36 static void gdm_port_destruct(struct tty_port *port)
37 {
38 struct gdm *gdm = container_of(port, struct gdm, port);
39
40 mutex_lock(&gdm_table_lock);
41 gdm_table[gdm->index][gdm->minor] = NULL;
42 mutex_unlock(&gdm_table_lock);
43
44 kfree(gdm);
45 }
46
47 static const struct tty_port_operations gdm_port_ops = {
48 .destruct = gdm_port_destruct,
49 };
50
gdm_tty_install(struct tty_driver * driver,struct tty_struct * tty)51 static int gdm_tty_install(struct tty_driver *driver, struct tty_struct *tty)
52 {
53 struct gdm *gdm = NULL;
54 int ret;
55
56 ret = match_string(DRIVER_STRING, TTY_MAX_COUNT,
57 tty->driver->driver_name);
58 if (ret < 0)
59 return -ENODEV;
60
61 mutex_lock(&gdm_table_lock);
62 gdm = gdm_table[ret][tty->index];
63 if (!gdm) {
64 mutex_unlock(&gdm_table_lock);
65 return -ENODEV;
66 }
67
68 tty_port_get(&gdm->port);
69
70 ret = tty_standard_install(driver, tty);
71 if (ret) {
72 tty_port_put(&gdm->port);
73 mutex_unlock(&gdm_table_lock);
74 return ret;
75 }
76
77 tty->driver_data = gdm;
78 mutex_unlock(&gdm_table_lock);
79
80 return 0;
81 }
82
gdm_tty_open(struct tty_struct * tty,struct file * filp)83 static int gdm_tty_open(struct tty_struct *tty, struct file *filp)
84 {
85 struct gdm *gdm = tty->driver_data;
86
87 return tty_port_open(&gdm->port, tty, filp);
88 }
89
gdm_tty_cleanup(struct tty_struct * tty)90 static void gdm_tty_cleanup(struct tty_struct *tty)
91 {
92 struct gdm *gdm = tty->driver_data;
93
94 tty_port_put(&gdm->port);
95 }
96
gdm_tty_hangup(struct tty_struct * tty)97 static void gdm_tty_hangup(struct tty_struct *tty)
98 {
99 struct gdm *gdm = tty->driver_data;
100
101 tty_port_hangup(&gdm->port);
102 }
103
gdm_tty_close(struct tty_struct * tty,struct file * filp)104 static void gdm_tty_close(struct tty_struct *tty, struct file *filp)
105 {
106 struct gdm *gdm = tty->driver_data;
107
108 tty_port_close(&gdm->port, tty, filp);
109 }
110
gdm_tty_recv_complete(void * data,int len,int index,struct tty_dev * tty_dev,int complete)111 static int gdm_tty_recv_complete(void *data,
112 int len,
113 int index,
114 struct tty_dev *tty_dev,
115 int complete)
116 {
117 struct gdm *gdm = tty_dev->gdm[index];
118
119 if (!gdm_tty_ready(gdm)) {
120 if (complete == RECV_PACKET_PROCESS_COMPLETE)
121 gdm->tty_dev->recv_func(gdm->tty_dev->priv_dev,
122 gdm_tty_recv_complete);
123 return TO_HOST_PORT_CLOSE;
124 }
125
126 if (data && len) {
127 if (tty_buffer_request_room(&gdm->port, len) == len) {
128 tty_insert_flip_string(&gdm->port, data, len);
129 tty_flip_buffer_push(&gdm->port);
130 } else {
131 return TO_HOST_BUFFER_REQUEST_FAIL;
132 }
133 }
134
135 if (complete == RECV_PACKET_PROCESS_COMPLETE)
136 gdm->tty_dev->recv_func(gdm->tty_dev->priv_dev,
137 gdm_tty_recv_complete);
138
139 return 0;
140 }
141
gdm_tty_send_complete(void * arg)142 static void gdm_tty_send_complete(void *arg)
143 {
144 struct gdm *gdm = arg;
145
146 if (!gdm_tty_ready(gdm))
147 return;
148
149 tty_port_tty_wakeup(&gdm->port);
150 }
151
gdm_tty_write(struct tty_struct * tty,const u8 * buf,size_t len)152 static ssize_t gdm_tty_write(struct tty_struct *tty, const u8 *buf, size_t len)
153 {
154 struct gdm *gdm = tty->driver_data;
155 size_t remain = len;
156 size_t sent_len = 0;
157
158 if (!gdm_tty_ready(gdm))
159 return -ENODEV;
160
161 while (remain) {
162 size_t sending_len = min_t(size_t, MUX_TX_MAX_SIZE, remain);
163 gdm->tty_dev->send_func(gdm->tty_dev->priv_dev,
164 (void *)(buf + sent_len),
165 sending_len,
166 gdm->index,
167 gdm_tty_send_complete,
168 gdm);
169 sent_len += sending_len;
170 remain -= sending_len;
171 }
172
173 return len;
174 }
175
gdm_tty_write_room(struct tty_struct * tty)176 static unsigned int gdm_tty_write_room(struct tty_struct *tty)
177 {
178 struct gdm *gdm = tty->driver_data;
179
180 if (!gdm_tty_ready(gdm))
181 return 0;
182
183 return WRITE_SIZE;
184 }
185
register_lte_tty_device(struct tty_dev * tty_dev,struct device * device)186 int register_lte_tty_device(struct tty_dev *tty_dev, struct device *device)
187 {
188 struct gdm *gdm;
189 int i;
190 int j;
191
192 for (i = 0; i < TTY_MAX_COUNT; i++) {
193 gdm = kmalloc(sizeof(*gdm), GFP_KERNEL);
194 if (!gdm)
195 return -ENOMEM;
196
197 mutex_lock(&gdm_table_lock);
198 for (j = 0; j < GDM_TTY_MINOR; j++) {
199 if (!gdm_table[i][j])
200 break;
201 }
202
203 if (j == GDM_TTY_MINOR) {
204 kfree(gdm);
205 mutex_unlock(&gdm_table_lock);
206 return -EINVAL;
207 }
208
209 gdm_table[i][j] = gdm;
210 mutex_unlock(&gdm_table_lock);
211
212 tty_dev->gdm[i] = gdm;
213 tty_port_init(&gdm->port);
214
215 gdm->port.ops = &gdm_port_ops;
216 gdm->index = i;
217 gdm->minor = j;
218 gdm->tty_dev = tty_dev;
219
220 tty_port_register_device(&gdm->port, gdm_driver[i],
221 gdm->minor, device);
222 }
223
224 for (i = 0; i < MAX_ISSUE_NUM; i++)
225 gdm->tty_dev->recv_func(gdm->tty_dev->priv_dev,
226 gdm_tty_recv_complete);
227
228 return 0;
229 }
230
unregister_lte_tty_device(struct tty_dev * tty_dev)231 void unregister_lte_tty_device(struct tty_dev *tty_dev)
232 {
233 struct gdm *gdm;
234 struct tty_struct *tty;
235 int i;
236
237 for (i = 0; i < TTY_MAX_COUNT; i++) {
238 gdm = tty_dev->gdm[i];
239 if (!gdm)
240 continue;
241
242 mutex_lock(&gdm_table_lock);
243 gdm_table[gdm->index][gdm->minor] = NULL;
244 mutex_unlock(&gdm_table_lock);
245
246 tty = tty_port_tty_get(&gdm->port);
247 if (tty) {
248 tty_vhangup(tty);
249 tty_kref_put(tty);
250 }
251
252 tty_unregister_device(gdm_driver[i], gdm->minor);
253 tty_port_put(&gdm->port);
254 }
255 }
256
257 static const struct tty_operations gdm_tty_ops = {
258 .install = gdm_tty_install,
259 .open = gdm_tty_open,
260 .close = gdm_tty_close,
261 .cleanup = gdm_tty_cleanup,
262 .hangup = gdm_tty_hangup,
263 .write = gdm_tty_write,
264 .write_room = gdm_tty_write_room,
265 };
266
register_lte_tty_driver(void)267 int register_lte_tty_driver(void)
268 {
269 struct tty_driver *tty_driver;
270 int i;
271 int ret;
272
273 for (i = 0; i < TTY_MAX_COUNT; i++) {
274 tty_driver = tty_alloc_driver(GDM_TTY_MINOR,
275 TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV);
276 if (IS_ERR(tty_driver))
277 return PTR_ERR(tty_driver);
278
279 tty_driver->owner = THIS_MODULE;
280 tty_driver->driver_name = DRIVER_STRING[i];
281 tty_driver->name = DEVICE_STRING[i];
282 tty_driver->major = GDM_TTY_MAJOR;
283 tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
284 tty_driver->subtype = SERIAL_TYPE_NORMAL;
285 tty_driver->init_termios = tty_std_termios;
286 tty_driver->init_termios.c_cflag = B9600 | CS8 | HUPCL | CLOCAL;
287 tty_driver->init_termios.c_lflag = ISIG | ICANON | IEXTEN;
288 tty_set_operations(tty_driver, &gdm_tty_ops);
289
290 ret = tty_register_driver(tty_driver);
291 if (ret) {
292 tty_driver_kref_put(tty_driver);
293 return ret;
294 }
295
296 gdm_driver[i] = tty_driver;
297 }
298
299 return ret;
300 }
301
unregister_lte_tty_driver(void)302 void unregister_lte_tty_driver(void)
303 {
304 struct tty_driver *tty_driver;
305 int i;
306
307 for (i = 0; i < TTY_MAX_COUNT; i++) {
308 tty_driver = gdm_driver[i];
309 if (tty_driver) {
310 tty_unregister_driver(tty_driver);
311 tty_driver_kref_put(tty_driver);
312 }
313 }
314 }
315
316