1 /** 2 * xhci-dbgtty.c - tty glue for xHCI debug capability 3 * 4 * Copyright (C) 2017 Intel Corporation 5 * 6 * Author: Lu Baolu <baolu.lu@linux.intel.com> 7 */ 8 9 #include <linux/slab.h> 10 #include <linux/tty.h> 11 #include <linux/tty_flip.h> 12 13 #include "xhci.h" 14 #include "xhci-dbgcap.h" 15 16 static unsigned int 17 dbc_send_packet(struct dbc_port *port, char *packet, unsigned int size) 18 { 19 unsigned int len; 20 21 len = kfifo_len(&port->write_fifo); 22 if (len < size) 23 size = len; 24 if (size != 0) 25 size = kfifo_out(&port->write_fifo, packet, size); 26 return size; 27 } 28 29 static int dbc_start_tx(struct dbc_port *port) 30 __releases(&port->port_lock) 31 __acquires(&port->port_lock) 32 { 33 int len; 34 struct dbc_request *req; 35 int status = 0; 36 bool do_tty_wake = false; 37 struct list_head *pool = &port->write_pool; 38 39 while (!list_empty(pool)) { 40 req = list_entry(pool->next, struct dbc_request, list_pool); 41 len = dbc_send_packet(port, req->buf, DBC_MAX_PACKET); 42 if (len == 0) 43 break; 44 do_tty_wake = true; 45 46 req->length = len; 47 list_del(&req->list_pool); 48 49 spin_unlock(&port->port_lock); 50 status = dbc_ep_queue(port->out, req, GFP_ATOMIC); 51 spin_lock(&port->port_lock); 52 53 if (status) { 54 list_add(&req->list_pool, pool); 55 break; 56 } 57 } 58 59 if (do_tty_wake && port->port.tty) 60 tty_wakeup(port->port.tty); 61 62 return status; 63 } 64 65 static void dbc_start_rx(struct dbc_port *port) 66 __releases(&port->port_lock) 67 __acquires(&port->port_lock) 68 { 69 struct dbc_request *req; 70 int status; 71 struct list_head *pool = &port->read_pool; 72 73 while (!list_empty(pool)) { 74 if (!port->port.tty) 75 break; 76 77 req = list_entry(pool->next, struct dbc_request, list_pool); 78 list_del(&req->list_pool); 79 req->length = DBC_MAX_PACKET; 80 81 spin_unlock(&port->port_lock); 82 status = dbc_ep_queue(port->in, req, GFP_ATOMIC); 83 spin_lock(&port->port_lock); 84 85 if (status) { 86 list_add(&req->list_pool, pool); 87 break; 88 } 89 } 90 } 91 92 static void 93 dbc_read_complete(struct xhci_hcd *xhci, struct dbc_request *req) 94 { 95 unsigned long flags; 96 struct xhci_dbc *dbc = xhci->dbc; 97 struct dbc_port *port = &dbc->port; 98 99 spin_lock_irqsave(&port->port_lock, flags); 100 list_add_tail(&req->list_pool, &port->read_queue); 101 tasklet_schedule(&port->push); 102 spin_unlock_irqrestore(&port->port_lock, flags); 103 } 104 105 static void dbc_write_complete(struct xhci_hcd *xhci, struct dbc_request *req) 106 { 107 unsigned long flags; 108 struct xhci_dbc *dbc = xhci->dbc; 109 struct dbc_port *port = &dbc->port; 110 111 spin_lock_irqsave(&port->port_lock, flags); 112 list_add(&req->list_pool, &port->write_pool); 113 switch (req->status) { 114 case 0: 115 dbc_start_tx(port); 116 break; 117 case -ESHUTDOWN: 118 break; 119 default: 120 xhci_warn(xhci, "unexpected write complete status %d\n", 121 req->status); 122 break; 123 } 124 spin_unlock_irqrestore(&port->port_lock, flags); 125 } 126 127 static void xhci_dbc_free_req(struct dbc_ep *dep, struct dbc_request *req) 128 { 129 kfree(req->buf); 130 dbc_free_request(dep, req); 131 } 132 133 static int 134 xhci_dbc_alloc_requests(struct dbc_ep *dep, struct list_head *head, 135 void (*fn)(struct xhci_hcd *, struct dbc_request *)) 136 { 137 int i; 138 struct dbc_request *req; 139 140 for (i = 0; i < DBC_QUEUE_SIZE; i++) { 141 req = dbc_alloc_request(dep, GFP_ATOMIC); 142 if (!req) 143 break; 144 145 req->length = DBC_MAX_PACKET; 146 req->buf = kmalloc(req->length, GFP_KERNEL); 147 if (!req->buf) { 148 xhci_dbc_free_req(dep, req); 149 break; 150 } 151 152 req->complete = fn; 153 list_add_tail(&req->list_pool, head); 154 } 155 156 return list_empty(head) ? -ENOMEM : 0; 157 } 158 159 static void 160 xhci_dbc_free_requests(struct dbc_ep *dep, struct list_head *head) 161 { 162 struct dbc_request *req; 163 164 while (!list_empty(head)) { 165 req = list_entry(head->next, struct dbc_request, list_pool); 166 list_del(&req->list_pool); 167 xhci_dbc_free_req(dep, req); 168 } 169 } 170 171 static int dbc_tty_install(struct tty_driver *driver, struct tty_struct *tty) 172 { 173 struct dbc_port *port = driver->driver_state; 174 175 tty->driver_data = port; 176 177 return tty_port_install(&port->port, driver, tty); 178 } 179 180 static int dbc_tty_open(struct tty_struct *tty, struct file *file) 181 { 182 struct dbc_port *port = tty->driver_data; 183 184 return tty_port_open(&port->port, tty, file); 185 } 186 187 static void dbc_tty_close(struct tty_struct *tty, struct file *file) 188 { 189 struct dbc_port *port = tty->driver_data; 190 191 tty_port_close(&port->port, tty, file); 192 } 193 194 static int dbc_tty_write(struct tty_struct *tty, 195 const unsigned char *buf, 196 int count) 197 { 198 struct dbc_port *port = tty->driver_data; 199 unsigned long flags; 200 201 spin_lock_irqsave(&port->port_lock, flags); 202 if (count) 203 count = kfifo_in(&port->write_fifo, buf, count); 204 dbc_start_tx(port); 205 spin_unlock_irqrestore(&port->port_lock, flags); 206 207 return count; 208 } 209 210 static int dbc_tty_put_char(struct tty_struct *tty, unsigned char ch) 211 { 212 struct dbc_port *port = tty->driver_data; 213 unsigned long flags; 214 int status; 215 216 spin_lock_irqsave(&port->port_lock, flags); 217 status = kfifo_put(&port->write_fifo, ch); 218 spin_unlock_irqrestore(&port->port_lock, flags); 219 220 return status; 221 } 222 223 static void dbc_tty_flush_chars(struct tty_struct *tty) 224 { 225 struct dbc_port *port = tty->driver_data; 226 unsigned long flags; 227 228 spin_lock_irqsave(&port->port_lock, flags); 229 dbc_start_tx(port); 230 spin_unlock_irqrestore(&port->port_lock, flags); 231 } 232 233 static int dbc_tty_write_room(struct tty_struct *tty) 234 { 235 struct dbc_port *port = tty->driver_data; 236 unsigned long flags; 237 int room = 0; 238 239 spin_lock_irqsave(&port->port_lock, flags); 240 room = kfifo_avail(&port->write_fifo); 241 spin_unlock_irqrestore(&port->port_lock, flags); 242 243 return room; 244 } 245 246 static int dbc_tty_chars_in_buffer(struct tty_struct *tty) 247 { 248 struct dbc_port *port = tty->driver_data; 249 unsigned long flags; 250 int chars = 0; 251 252 spin_lock_irqsave(&port->port_lock, flags); 253 chars = kfifo_len(&port->write_fifo); 254 spin_unlock_irqrestore(&port->port_lock, flags); 255 256 return chars; 257 } 258 259 static void dbc_tty_unthrottle(struct tty_struct *tty) 260 { 261 struct dbc_port *port = tty->driver_data; 262 unsigned long flags; 263 264 spin_lock_irqsave(&port->port_lock, flags); 265 tasklet_schedule(&port->push); 266 spin_unlock_irqrestore(&port->port_lock, flags); 267 } 268 269 static const struct tty_operations dbc_tty_ops = { 270 .install = dbc_tty_install, 271 .open = dbc_tty_open, 272 .close = dbc_tty_close, 273 .write = dbc_tty_write, 274 .put_char = dbc_tty_put_char, 275 .flush_chars = dbc_tty_flush_chars, 276 .write_room = dbc_tty_write_room, 277 .chars_in_buffer = dbc_tty_chars_in_buffer, 278 .unthrottle = dbc_tty_unthrottle, 279 }; 280 281 static struct tty_driver *dbc_tty_driver; 282 283 int xhci_dbc_tty_register_driver(struct xhci_hcd *xhci) 284 { 285 int status; 286 struct xhci_dbc *dbc = xhci->dbc; 287 288 dbc_tty_driver = tty_alloc_driver(1, TTY_DRIVER_REAL_RAW | 289 TTY_DRIVER_DYNAMIC_DEV); 290 if (IS_ERR(dbc_tty_driver)) { 291 status = PTR_ERR(dbc_tty_driver); 292 dbc_tty_driver = NULL; 293 return status; 294 } 295 296 dbc_tty_driver->driver_name = "dbc_serial"; 297 dbc_tty_driver->name = "ttyDBC"; 298 299 dbc_tty_driver->type = TTY_DRIVER_TYPE_SERIAL; 300 dbc_tty_driver->subtype = SERIAL_TYPE_NORMAL; 301 dbc_tty_driver->init_termios = tty_std_termios; 302 dbc_tty_driver->init_termios.c_cflag = 303 B9600 | CS8 | CREAD | HUPCL | CLOCAL; 304 dbc_tty_driver->init_termios.c_ispeed = 9600; 305 dbc_tty_driver->init_termios.c_ospeed = 9600; 306 dbc_tty_driver->driver_state = &dbc->port; 307 308 tty_set_operations(dbc_tty_driver, &dbc_tty_ops); 309 310 status = tty_register_driver(dbc_tty_driver); 311 if (status) { 312 xhci_err(xhci, 313 "can't register dbc tty driver, err %d\n", status); 314 put_tty_driver(dbc_tty_driver); 315 dbc_tty_driver = NULL; 316 } 317 318 return status; 319 } 320 321 void xhci_dbc_tty_unregister_driver(void) 322 { 323 tty_unregister_driver(dbc_tty_driver); 324 put_tty_driver(dbc_tty_driver); 325 dbc_tty_driver = NULL; 326 } 327 328 static void dbc_rx_push(unsigned long _port) 329 { 330 struct dbc_request *req; 331 struct tty_struct *tty; 332 unsigned long flags; 333 bool do_push = false; 334 bool disconnect = false; 335 struct dbc_port *port = (void *)_port; 336 struct list_head *queue = &port->read_queue; 337 338 spin_lock_irqsave(&port->port_lock, flags); 339 tty = port->port.tty; 340 while (!list_empty(queue)) { 341 req = list_first_entry(queue, struct dbc_request, list_pool); 342 343 if (tty && tty_throttled(tty)) 344 break; 345 346 switch (req->status) { 347 case 0: 348 break; 349 case -ESHUTDOWN: 350 disconnect = true; 351 break; 352 default: 353 pr_warn("ttyDBC0: unexpected RX status %d\n", 354 req->status); 355 break; 356 } 357 358 if (req->actual) { 359 char *packet = req->buf; 360 unsigned int n, size = req->actual; 361 int count; 362 363 n = port->n_read; 364 if (n) { 365 packet += n; 366 size -= n; 367 } 368 369 count = tty_insert_flip_string(&port->port, packet, 370 size); 371 if (count) 372 do_push = true; 373 if (count != size) { 374 port->n_read += count; 375 break; 376 } 377 port->n_read = 0; 378 } 379 380 list_move(&req->list_pool, &port->read_pool); 381 } 382 383 if (do_push) 384 tty_flip_buffer_push(&port->port); 385 386 if (!list_empty(queue) && tty) { 387 if (!tty_throttled(tty)) { 388 if (do_push) 389 tasklet_schedule(&port->push); 390 else 391 pr_warn("ttyDBC0: RX not scheduled?\n"); 392 } 393 } 394 395 if (!disconnect) 396 dbc_start_rx(port); 397 398 spin_unlock_irqrestore(&port->port_lock, flags); 399 } 400 401 static int dbc_port_activate(struct tty_port *_port, struct tty_struct *tty) 402 { 403 unsigned long flags; 404 struct dbc_port *port = container_of(_port, struct dbc_port, port); 405 406 spin_lock_irqsave(&port->port_lock, flags); 407 dbc_start_rx(port); 408 spin_unlock_irqrestore(&port->port_lock, flags); 409 410 return 0; 411 } 412 413 static const struct tty_port_operations dbc_port_ops = { 414 .activate = dbc_port_activate, 415 }; 416 417 static void 418 xhci_dbc_tty_init_port(struct xhci_hcd *xhci, struct dbc_port *port) 419 { 420 tty_port_init(&port->port); 421 spin_lock_init(&port->port_lock); 422 tasklet_init(&port->push, dbc_rx_push, (unsigned long)port); 423 INIT_LIST_HEAD(&port->read_pool); 424 INIT_LIST_HEAD(&port->read_queue); 425 INIT_LIST_HEAD(&port->write_pool); 426 427 port->in = get_in_ep(xhci); 428 port->out = get_out_ep(xhci); 429 port->port.ops = &dbc_port_ops; 430 port->n_read = 0; 431 } 432 433 static void 434 xhci_dbc_tty_exit_port(struct dbc_port *port) 435 { 436 tasklet_kill(&port->push); 437 tty_port_destroy(&port->port); 438 } 439 440 int xhci_dbc_tty_register_device(struct xhci_hcd *xhci) 441 { 442 int ret; 443 struct device *tty_dev; 444 struct xhci_dbc *dbc = xhci->dbc; 445 struct dbc_port *port = &dbc->port; 446 447 xhci_dbc_tty_init_port(xhci, port); 448 tty_dev = tty_port_register_device(&port->port, 449 dbc_tty_driver, 0, NULL); 450 if (IS_ERR(tty_dev)) { 451 ret = PTR_ERR(tty_dev); 452 goto register_fail; 453 } 454 455 ret = kfifo_alloc(&port->write_fifo, DBC_WRITE_BUF_SIZE, GFP_KERNEL); 456 if (ret) 457 goto buf_alloc_fail; 458 459 ret = xhci_dbc_alloc_requests(port->in, &port->read_pool, 460 dbc_read_complete); 461 if (ret) 462 goto request_fail; 463 464 ret = xhci_dbc_alloc_requests(port->out, &port->write_pool, 465 dbc_write_complete); 466 if (ret) 467 goto request_fail; 468 469 port->registered = true; 470 471 return 0; 472 473 request_fail: 474 xhci_dbc_free_requests(port->in, &port->read_pool); 475 xhci_dbc_free_requests(port->out, &port->write_pool); 476 kfifo_free(&port->write_fifo); 477 478 buf_alloc_fail: 479 tty_unregister_device(dbc_tty_driver, 0); 480 481 register_fail: 482 xhci_dbc_tty_exit_port(port); 483 484 xhci_err(xhci, "can't register tty port, err %d\n", ret); 485 486 return ret; 487 } 488 489 void xhci_dbc_tty_unregister_device(struct xhci_hcd *xhci) 490 { 491 struct xhci_dbc *dbc = xhci->dbc; 492 struct dbc_port *port = &dbc->port; 493 494 tty_unregister_device(dbc_tty_driver, 0); 495 xhci_dbc_tty_exit_port(port); 496 port->registered = false; 497 498 kfifo_free(&port->write_fifo); 499 xhci_dbc_free_requests(get_out_ep(xhci), &port->read_pool); 500 xhci_dbc_free_requests(get_out_ep(xhci), &port->read_queue); 501 xhci_dbc_free_requests(get_in_ep(xhci), &port->write_pool); 502 } 503