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 2048UL 21 22 #define MUX_TX_MAX_SIZE 2048UL 23 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 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 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 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 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 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 } 103 104 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 } 110 111 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 } 141 142 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 } 151 152 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 if (!len) 162 return 0; 163 164 while (1) { 165 size_t sending_len = min(MUX_TX_MAX_SIZE, remain); 166 gdm->tty_dev->send_func(gdm->tty_dev->priv_dev, 167 (void *)(buf + sent_len), 168 sending_len, 169 gdm->index, 170 gdm_tty_send_complete, 171 gdm); 172 sent_len += sending_len; 173 remain -= sending_len; 174 if (remain <= 0) 175 break; 176 } 177 178 return len; 179 } 180 181 static unsigned int gdm_tty_write_room(struct tty_struct *tty) 182 { 183 struct gdm *gdm = tty->driver_data; 184 185 if (!gdm_tty_ready(gdm)) 186 return 0; 187 188 return WRITE_SIZE; 189 } 190 191 int register_lte_tty_device(struct tty_dev *tty_dev, struct device *device) 192 { 193 struct gdm *gdm; 194 int i; 195 int j; 196 197 for (i = 0; i < TTY_MAX_COUNT; i++) { 198 gdm = kmalloc(sizeof(*gdm), GFP_KERNEL); 199 if (!gdm) 200 return -ENOMEM; 201 202 mutex_lock(&gdm_table_lock); 203 for (j = 0; j < GDM_TTY_MINOR; j++) { 204 if (!gdm_table[i][j]) 205 break; 206 } 207 208 if (j == GDM_TTY_MINOR) { 209 kfree(gdm); 210 mutex_unlock(&gdm_table_lock); 211 return -EINVAL; 212 } 213 214 gdm_table[i][j] = gdm; 215 mutex_unlock(&gdm_table_lock); 216 217 tty_dev->gdm[i] = gdm; 218 tty_port_init(&gdm->port); 219 220 gdm->port.ops = &gdm_port_ops; 221 gdm->index = i; 222 gdm->minor = j; 223 gdm->tty_dev = tty_dev; 224 225 tty_port_register_device(&gdm->port, gdm_driver[i], 226 gdm->minor, device); 227 } 228 229 for (i = 0; i < MAX_ISSUE_NUM; i++) 230 gdm->tty_dev->recv_func(gdm->tty_dev->priv_dev, 231 gdm_tty_recv_complete); 232 233 return 0; 234 } 235 236 void unregister_lte_tty_device(struct tty_dev *tty_dev) 237 { 238 struct gdm *gdm; 239 struct tty_struct *tty; 240 int i; 241 242 for (i = 0; i < TTY_MAX_COUNT; i++) { 243 gdm = tty_dev->gdm[i]; 244 if (!gdm) 245 continue; 246 247 mutex_lock(&gdm_table_lock); 248 gdm_table[gdm->index][gdm->minor] = NULL; 249 mutex_unlock(&gdm_table_lock); 250 251 tty = tty_port_tty_get(&gdm->port); 252 if (tty) { 253 tty_vhangup(tty); 254 tty_kref_put(tty); 255 } 256 257 tty_unregister_device(gdm_driver[i], gdm->minor); 258 tty_port_put(&gdm->port); 259 } 260 } 261 262 static const struct tty_operations gdm_tty_ops = { 263 .install = gdm_tty_install, 264 .open = gdm_tty_open, 265 .close = gdm_tty_close, 266 .cleanup = gdm_tty_cleanup, 267 .hangup = gdm_tty_hangup, 268 .write = gdm_tty_write, 269 .write_room = gdm_tty_write_room, 270 }; 271 272 int register_lte_tty_driver(void) 273 { 274 struct tty_driver *tty_driver; 275 int i; 276 int ret; 277 278 for (i = 0; i < TTY_MAX_COUNT; i++) { 279 tty_driver = tty_alloc_driver(GDM_TTY_MINOR, 280 TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV); 281 if (IS_ERR(tty_driver)) 282 return PTR_ERR(tty_driver); 283 284 tty_driver->owner = THIS_MODULE; 285 tty_driver->driver_name = DRIVER_STRING[i]; 286 tty_driver->name = DEVICE_STRING[i]; 287 tty_driver->major = GDM_TTY_MAJOR; 288 tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 289 tty_driver->subtype = SERIAL_TYPE_NORMAL; 290 tty_driver->init_termios = tty_std_termios; 291 tty_driver->init_termios.c_cflag = B9600 | CS8 | HUPCL | CLOCAL; 292 tty_driver->init_termios.c_lflag = ISIG | ICANON | IEXTEN; 293 tty_set_operations(tty_driver, &gdm_tty_ops); 294 295 ret = tty_register_driver(tty_driver); 296 if (ret) { 297 tty_driver_kref_put(tty_driver); 298 return ret; 299 } 300 301 gdm_driver[i] = tty_driver; 302 } 303 304 return ret; 305 } 306 307 void unregister_lte_tty_driver(void) 308 { 309 struct tty_driver *tty_driver; 310 int i; 311 312 for (i = 0; i < TTY_MAX_COUNT; i++) { 313 tty_driver = gdm_driver[i]; 314 if (tty_driver) { 315 tty_unregister_driver(tty_driver); 316 tty_driver_kref_put(tty_driver); 317 } 318 } 319 } 320 321