1 /* 2 * IEEE-1284 implementation for parport. 3 * 4 * Authors: Phil Blundell <philb@gnu.org> 5 * Carsten Gross <carsten@sol.wohnheim.uni-ulm.de> 6 * Jose Renau <renau@acm.org> 7 * Tim Waugh <tim@cyberelk.demon.co.uk> (largely rewritten) 8 * 9 * This file is responsible for IEEE 1284 negotiation, and for handing 10 * read/write requests to low-level drivers. 11 * 12 * Any part of this program may be used in documents licensed under 13 * the GNU Free Documentation License, Version 1.1 or any later version 14 * published by the Free Software Foundation. 15 * 16 * Various hacks, Fred Barnes <frmb2@ukc.ac.uk>, 04/2000 17 */ 18 19 #include <linux/module.h> 20 #include <linux/threads.h> 21 #include <linux/parport.h> 22 #include <linux/delay.h> 23 #include <linux/kernel.h> 24 #include <linux/interrupt.h> 25 #include <linux/timer.h> 26 #include <linux/sched.h> 27 28 #undef DEBUG /* undef me for production */ 29 30 #ifdef CONFIG_LP_CONSOLE 31 #undef DEBUG /* Don't want a garbled console */ 32 #endif 33 34 #ifdef DEBUG 35 #define DPRINTK(stuff...) printk (stuff) 36 #else 37 #define DPRINTK(stuff...) 38 #endif 39 40 /* Make parport_wait_peripheral wake up. 41 * It will be useful to call this from an interrupt handler. */ 42 static void parport_ieee1284_wakeup (struct parport *port) 43 { 44 up (&port->physport->ieee1284.irq); 45 } 46 47 static struct parport *port_from_cookie[PARPORT_MAX]; 48 static void timeout_waiting_on_port (unsigned long cookie) 49 { 50 parport_ieee1284_wakeup (port_from_cookie[cookie % PARPORT_MAX]); 51 } 52 53 /** 54 * parport_wait_event - wait for an event on a parallel port 55 * @port: port to wait on 56 * @timeout: time to wait (in jiffies) 57 * 58 * This function waits for up to @timeout jiffies for an 59 * interrupt to occur on a parallel port. If the port timeout is 60 * set to zero, it returns immediately. 61 * 62 * If an interrupt occurs before the timeout period elapses, this 63 * function returns zero immediately. If it times out, it returns 64 * one. An error code less than zero indicates an error (most 65 * likely a pending signal), and the calling code should finish 66 * what it's doing as soon as it can. 67 */ 68 69 int parport_wait_event (struct parport *port, signed long timeout) 70 { 71 int ret; 72 struct timer_list timer; 73 74 if (!port->physport->cad->timeout) 75 /* Zero timeout is special, and we can't down() the 76 semaphore. */ 77 return 1; 78 79 init_timer_on_stack(&timer); 80 timer.expires = jiffies + timeout; 81 timer.function = timeout_waiting_on_port; 82 port_from_cookie[port->number % PARPORT_MAX] = port; 83 timer.data = port->number; 84 85 add_timer (&timer); 86 ret = down_interruptible (&port->physport->ieee1284.irq); 87 if (!del_timer_sync(&timer) && !ret) 88 /* Timed out. */ 89 ret = 1; 90 91 destroy_timer_on_stack(&timer); 92 93 return ret; 94 } 95 96 /** 97 * parport_poll_peripheral - poll status lines 98 * @port: port to watch 99 * @mask: status lines to watch 100 * @result: desired values of chosen status lines 101 * @usec: timeout 102 * 103 * This function busy-waits until the masked status lines have 104 * the desired values, or until the timeout period elapses. The 105 * @mask and @result parameters are bitmasks, with the bits 106 * defined by the constants in parport.h: %PARPORT_STATUS_BUSY, 107 * and so on. 108 * 109 * This function does not call schedule(); instead it busy-waits 110 * using udelay(). It currently has a resolution of 5usec. 111 * 112 * If the status lines take on the desired values before the 113 * timeout period elapses, parport_poll_peripheral() returns zero 114 * immediately. A return value greater than zero indicates 115 * a timeout. An error code (less than zero) indicates an error, 116 * most likely a signal that arrived, and the caller should 117 * finish what it is doing as soon as possible. 118 */ 119 120 int parport_poll_peripheral(struct parport *port, 121 unsigned char mask, 122 unsigned char result, 123 int usec) 124 { 125 /* Zero return code is success, >0 is timeout. */ 126 int count = usec / 5 + 2; 127 int i; 128 unsigned char status; 129 for (i = 0; i < count; i++) { 130 status = parport_read_status (port); 131 if ((status & mask) == result) 132 return 0; 133 if (signal_pending (current)) 134 return -EINTR; 135 if (need_resched()) 136 break; 137 if (i >= 2) 138 udelay (5); 139 } 140 141 return 1; 142 } 143 144 /** 145 * parport_wait_peripheral - wait for status lines to change in 35ms 146 * @port: port to watch 147 * @mask: status lines to watch 148 * @result: desired values of chosen status lines 149 * 150 * This function waits until the masked status lines have the 151 * desired values, or until 35ms have elapsed (see IEEE 1284-1994 152 * page 24 to 25 for why this value in particular is hardcoded). 153 * The @mask and @result parameters are bitmasks, with the bits 154 * defined by the constants in parport.h: %PARPORT_STATUS_BUSY, 155 * and so on. 156 * 157 * The port is polled quickly to start off with, in anticipation 158 * of a fast response from the peripheral. This fast polling 159 * time is configurable (using /proc), and defaults to 500usec. 160 * If the timeout for this port (see parport_set_timeout()) is 161 * zero, the fast polling time is 35ms, and this function does 162 * not call schedule(). 163 * 164 * If the timeout for this port is non-zero, after the fast 165 * polling fails it uses parport_wait_event() to wait for up to 166 * 10ms, waking up if an interrupt occurs. 167 */ 168 169 int parport_wait_peripheral(struct parport *port, 170 unsigned char mask, 171 unsigned char result) 172 { 173 int ret; 174 int usec; 175 unsigned long deadline; 176 unsigned char status; 177 178 usec = port->physport->spintime; /* usecs of fast polling */ 179 if (!port->physport->cad->timeout) 180 /* A zero timeout is "special": busy wait for the 181 entire 35ms. */ 182 usec = 35000; 183 184 /* Fast polling. 185 * 186 * This should be adjustable. 187 * How about making a note (in the device structure) of how long 188 * it takes, so we know for next time? 189 */ 190 ret = parport_poll_peripheral (port, mask, result, usec); 191 if (ret != 1) 192 return ret; 193 194 if (!port->physport->cad->timeout) 195 /* We may be in an interrupt handler, so we can't poll 196 * slowly anyway. */ 197 return 1; 198 199 /* 40ms of slow polling. */ 200 deadline = jiffies + msecs_to_jiffies(40); 201 while (time_before (jiffies, deadline)) { 202 if (signal_pending (current)) 203 return -EINTR; 204 205 /* Wait for 10ms (or until an interrupt occurs if 206 * the handler is set) */ 207 if ((ret = parport_wait_event (port, msecs_to_jiffies(10))) < 0) 208 return ret; 209 210 status = parport_read_status (port); 211 if ((status & mask) == result) 212 return 0; 213 214 if (!ret) { 215 /* parport_wait_event didn't time out, but the 216 * peripheral wasn't actually ready either. 217 * Wait for another 10ms. */ 218 schedule_timeout_interruptible(msecs_to_jiffies(10)); 219 } 220 } 221 222 return 1; 223 } 224 225 #ifdef CONFIG_PARPORT_1284 226 /* Terminate a negotiated mode. */ 227 static void parport_ieee1284_terminate (struct parport *port) 228 { 229 int r; 230 port = port->physport; 231 232 /* EPP terminates differently. */ 233 switch (port->ieee1284.mode) { 234 case IEEE1284_MODE_EPP: 235 case IEEE1284_MODE_EPPSL: 236 case IEEE1284_MODE_EPPSWE: 237 /* Terminate from EPP mode. */ 238 239 /* Event 68: Set nInit low */ 240 parport_frob_control (port, PARPORT_CONTROL_INIT, 0); 241 udelay (50); 242 243 /* Event 69: Set nInit high, nSelectIn low */ 244 parport_frob_control (port, 245 PARPORT_CONTROL_SELECT 246 | PARPORT_CONTROL_INIT, 247 PARPORT_CONTROL_SELECT 248 | PARPORT_CONTROL_INIT); 249 break; 250 251 case IEEE1284_MODE_ECP: 252 case IEEE1284_MODE_ECPRLE: 253 case IEEE1284_MODE_ECPSWE: 254 /* In ECP we can only terminate from fwd idle phase. */ 255 if (port->ieee1284.phase != IEEE1284_PH_FWD_IDLE) { 256 /* Event 47: Set nInit high */ 257 parport_frob_control (port, 258 PARPORT_CONTROL_INIT 259 | PARPORT_CONTROL_AUTOFD, 260 PARPORT_CONTROL_INIT 261 | PARPORT_CONTROL_AUTOFD); 262 263 /* Event 49: PError goes high */ 264 r = parport_wait_peripheral (port, 265 PARPORT_STATUS_PAPEROUT, 266 PARPORT_STATUS_PAPEROUT); 267 if (r) 268 DPRINTK (KERN_INFO "%s: Timeout at event 49\n", 269 port->name); 270 271 parport_data_forward (port); 272 DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n", 273 port->name); 274 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE; 275 } 276 277 /* fall-though.. */ 278 279 default: 280 /* Terminate from all other modes. */ 281 282 /* Event 22: Set nSelectIn low, nAutoFd high */ 283 parport_frob_control (port, 284 PARPORT_CONTROL_SELECT 285 | PARPORT_CONTROL_AUTOFD, 286 PARPORT_CONTROL_SELECT); 287 288 /* Event 24: nAck goes low */ 289 r = parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0); 290 if (r) 291 DPRINTK (KERN_INFO "%s: Timeout at event 24\n", 292 port->name); 293 294 /* Event 25: Set nAutoFd low */ 295 parport_frob_control (port, 296 PARPORT_CONTROL_AUTOFD, 297 PARPORT_CONTROL_AUTOFD); 298 299 /* Event 27: nAck goes high */ 300 r = parport_wait_peripheral (port, 301 PARPORT_STATUS_ACK, 302 PARPORT_STATUS_ACK); 303 if (r) 304 DPRINTK (KERN_INFO "%s: Timeout at event 27\n", 305 port->name); 306 307 /* Event 29: Set nAutoFd high */ 308 parport_frob_control (port, PARPORT_CONTROL_AUTOFD, 0); 309 } 310 311 port->ieee1284.mode = IEEE1284_MODE_COMPAT; 312 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE; 313 314 DPRINTK (KERN_DEBUG "%s: In compatibility (forward idle) mode\n", 315 port->name); 316 } 317 #endif /* IEEE1284 support */ 318 319 /** 320 * parport_negotiate - negotiate an IEEE 1284 mode 321 * @port: port to use 322 * @mode: mode to negotiate to 323 * 324 * Use this to negotiate to a particular IEEE 1284 transfer mode. 325 * The @mode parameter should be one of the constants in 326 * parport.h starting %IEEE1284_MODE_xxx. 327 * 328 * The return value is 0 if the peripheral has accepted the 329 * negotiation to the mode specified, -1 if the peripheral is not 330 * IEEE 1284 compliant (or not present), or 1 if the peripheral 331 * has rejected the negotiation. 332 */ 333 334 int parport_negotiate (struct parport *port, int mode) 335 { 336 #ifndef CONFIG_PARPORT_1284 337 if (mode == IEEE1284_MODE_COMPAT) 338 return 0; 339 printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n"); 340 return -1; 341 #else 342 int m = mode & ~IEEE1284_ADDR; 343 int r; 344 unsigned char xflag; 345 346 port = port->physport; 347 348 /* Is there anything to do? */ 349 if (port->ieee1284.mode == mode) 350 return 0; 351 352 /* Is the difference just an address-or-not bit? */ 353 if ((port->ieee1284.mode & ~IEEE1284_ADDR) == (mode & ~IEEE1284_ADDR)){ 354 port->ieee1284.mode = mode; 355 return 0; 356 } 357 358 /* Go to compatibility forward idle mode */ 359 if (port->ieee1284.mode != IEEE1284_MODE_COMPAT) 360 parport_ieee1284_terminate (port); 361 362 if (mode == IEEE1284_MODE_COMPAT) 363 /* Compatibility mode: no negotiation. */ 364 return 0; 365 366 switch (mode) { 367 case IEEE1284_MODE_ECPSWE: 368 m = IEEE1284_MODE_ECP; 369 break; 370 case IEEE1284_MODE_EPPSL: 371 case IEEE1284_MODE_EPPSWE: 372 m = IEEE1284_MODE_EPP; 373 break; 374 case IEEE1284_MODE_BECP: 375 return -ENOSYS; /* FIXME (implement BECP) */ 376 } 377 378 if (mode & IEEE1284_EXT_LINK) 379 m = 1<<7; /* request extensibility link */ 380 381 port->ieee1284.phase = IEEE1284_PH_NEGOTIATION; 382 383 /* Start off with nStrobe and nAutoFd high, and nSelectIn low */ 384 parport_frob_control (port, 385 PARPORT_CONTROL_STROBE 386 | PARPORT_CONTROL_AUTOFD 387 | PARPORT_CONTROL_SELECT, 388 PARPORT_CONTROL_SELECT); 389 udelay(1); 390 391 /* Event 0: Set data */ 392 parport_data_forward (port); 393 parport_write_data (port, m); 394 udelay (400); /* Shouldn't need to wait this long. */ 395 396 /* Event 1: Set nSelectIn high, nAutoFd low */ 397 parport_frob_control (port, 398 PARPORT_CONTROL_SELECT 399 | PARPORT_CONTROL_AUTOFD, 400 PARPORT_CONTROL_AUTOFD); 401 402 /* Event 2: PError, Select, nFault go high, nAck goes low */ 403 if (parport_wait_peripheral (port, 404 PARPORT_STATUS_ERROR 405 | PARPORT_STATUS_SELECT 406 | PARPORT_STATUS_PAPEROUT 407 | PARPORT_STATUS_ACK, 408 PARPORT_STATUS_ERROR 409 | PARPORT_STATUS_SELECT 410 | PARPORT_STATUS_PAPEROUT)) { 411 /* Timeout */ 412 parport_frob_control (port, 413 PARPORT_CONTROL_SELECT 414 | PARPORT_CONTROL_AUTOFD, 415 PARPORT_CONTROL_SELECT); 416 DPRINTK (KERN_DEBUG 417 "%s: Peripheral not IEEE1284 compliant (0x%02X)\n", 418 port->name, parport_read_status (port)); 419 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE; 420 return -1; /* Not IEEE1284 compliant */ 421 } 422 423 /* Event 3: Set nStrobe low */ 424 parport_frob_control (port, 425 PARPORT_CONTROL_STROBE, 426 PARPORT_CONTROL_STROBE); 427 428 /* Event 4: Set nStrobe and nAutoFd high */ 429 udelay (5); 430 parport_frob_control (port, 431 PARPORT_CONTROL_STROBE 432 | PARPORT_CONTROL_AUTOFD, 433 0); 434 435 /* Event 6: nAck goes high */ 436 if (parport_wait_peripheral (port, 437 PARPORT_STATUS_ACK, 438 PARPORT_STATUS_ACK)) { 439 /* This shouldn't really happen with a compliant device. */ 440 DPRINTK (KERN_DEBUG 441 "%s: Mode 0x%02x not supported? (0x%02x)\n", 442 port->name, mode, port->ops->read_status (port)); 443 parport_ieee1284_terminate (port); 444 return 1; 445 } 446 447 xflag = parport_read_status (port) & PARPORT_STATUS_SELECT; 448 449 /* xflag should be high for all modes other than nibble (0). */ 450 if (mode && !xflag) { 451 /* Mode not supported. */ 452 DPRINTK (KERN_DEBUG "%s: Mode 0x%02x rejected by peripheral\n", 453 port->name, mode); 454 parport_ieee1284_terminate (port); 455 return 1; 456 } 457 458 /* More to do if we've requested extensibility link. */ 459 if (mode & IEEE1284_EXT_LINK) { 460 m = mode & 0x7f; 461 udelay (1); 462 parport_write_data (port, m); 463 udelay (1); 464 465 /* Event 51: Set nStrobe low */ 466 parport_frob_control (port, 467 PARPORT_CONTROL_STROBE, 468 PARPORT_CONTROL_STROBE); 469 470 /* Event 52: nAck goes low */ 471 if (parport_wait_peripheral (port, PARPORT_STATUS_ACK, 0)) { 472 /* This peripheral is _very_ slow. */ 473 DPRINTK (KERN_DEBUG 474 "%s: Event 52 didn't happen\n", 475 port->name); 476 parport_ieee1284_terminate (port); 477 return 1; 478 } 479 480 /* Event 53: Set nStrobe high */ 481 parport_frob_control (port, 482 PARPORT_CONTROL_STROBE, 483 0); 484 485 /* Event 55: nAck goes high */ 486 if (parport_wait_peripheral (port, 487 PARPORT_STATUS_ACK, 488 PARPORT_STATUS_ACK)) { 489 /* This shouldn't really happen with a compliant 490 * device. */ 491 DPRINTK (KERN_DEBUG 492 "%s: Mode 0x%02x not supported? (0x%02x)\n", 493 port->name, mode, 494 port->ops->read_status (port)); 495 parport_ieee1284_terminate (port); 496 return 1; 497 } 498 499 /* Event 54: Peripheral sets XFlag to reflect support */ 500 xflag = parport_read_status (port) & PARPORT_STATUS_SELECT; 501 502 /* xflag should be high. */ 503 if (!xflag) { 504 /* Extended mode not supported. */ 505 DPRINTK (KERN_DEBUG "%s: Extended mode 0x%02x not " 506 "supported\n", port->name, mode); 507 parport_ieee1284_terminate (port); 508 return 1; 509 } 510 511 /* Any further setup is left to the caller. */ 512 } 513 514 /* Mode is supported */ 515 DPRINTK (KERN_DEBUG "%s: In mode 0x%02x\n", port->name, mode); 516 port->ieee1284.mode = mode; 517 518 /* But ECP is special */ 519 if (!(mode & IEEE1284_EXT_LINK) && (m & IEEE1284_MODE_ECP)) { 520 port->ieee1284.phase = IEEE1284_PH_ECP_SETUP; 521 522 /* Event 30: Set nAutoFd low */ 523 parport_frob_control (port, 524 PARPORT_CONTROL_AUTOFD, 525 PARPORT_CONTROL_AUTOFD); 526 527 /* Event 31: PError goes high. */ 528 r = parport_wait_peripheral (port, 529 PARPORT_STATUS_PAPEROUT, 530 PARPORT_STATUS_PAPEROUT); 531 if (r) { 532 DPRINTK (KERN_INFO "%s: Timeout at event 31\n", 533 port->name); 534 } 535 536 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE; 537 DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n", 538 port->name); 539 } else switch (mode) { 540 case IEEE1284_MODE_NIBBLE: 541 case IEEE1284_MODE_BYTE: 542 port->ieee1284.phase = IEEE1284_PH_REV_IDLE; 543 break; 544 default: 545 port->ieee1284.phase = IEEE1284_PH_FWD_IDLE; 546 } 547 548 549 return 0; 550 #endif /* IEEE1284 support */ 551 } 552 553 /* Acknowledge that the peripheral has data available. 554 * Events 18-20, in order to get from Reverse Idle phase 555 * to Host Busy Data Available. 556 * This will most likely be called from an interrupt. 557 * Returns zero if data was available. 558 */ 559 #ifdef CONFIG_PARPORT_1284 560 static int parport_ieee1284_ack_data_avail (struct parport *port) 561 { 562 if (parport_read_status (port) & PARPORT_STATUS_ERROR) 563 /* Event 18 didn't happen. */ 564 return -1; 565 566 /* Event 20: nAutoFd goes high. */ 567 port->ops->frob_control (port, PARPORT_CONTROL_AUTOFD, 0); 568 port->ieee1284.phase = IEEE1284_PH_HBUSY_DAVAIL; 569 return 0; 570 } 571 #endif /* IEEE1284 support */ 572 573 /* Handle an interrupt. */ 574 void parport_ieee1284_interrupt (void *handle) 575 { 576 struct parport *port = handle; 577 parport_ieee1284_wakeup (port); 578 579 #ifdef CONFIG_PARPORT_1284 580 if (port->ieee1284.phase == IEEE1284_PH_REV_IDLE) { 581 /* An interrupt in this phase means that data 582 * is now available. */ 583 DPRINTK (KERN_DEBUG "%s: Data available\n", port->name); 584 parport_ieee1284_ack_data_avail (port); 585 } 586 #endif /* IEEE1284 support */ 587 } 588 589 /** 590 * parport_write - write a block of data to a parallel port 591 * @port: port to write to 592 * @buffer: data buffer (in kernel space) 593 * @len: number of bytes of data to transfer 594 * 595 * This will write up to @len bytes of @buffer to the port 596 * specified, using the IEEE 1284 transfer mode most recently 597 * negotiated to (using parport_negotiate()), as long as that 598 * mode supports forward transfers (host to peripheral). 599 * 600 * It is the caller's responsibility to ensure that the first 601 * @len bytes of @buffer are valid. 602 * 603 * This function returns the number of bytes transferred (if zero 604 * or positive), or else an error code. 605 */ 606 607 ssize_t parport_write (struct parport *port, const void *buffer, size_t len) 608 { 609 #ifndef CONFIG_PARPORT_1284 610 return port->ops->compat_write_data (port, buffer, len, 0); 611 #else 612 ssize_t retval; 613 int mode = port->ieee1284.mode; 614 int addr = mode & IEEE1284_ADDR; 615 size_t (*fn) (struct parport *, const void *, size_t, int); 616 617 /* Ignore the device-ID-request bit and the address bit. */ 618 mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR); 619 620 /* Use the mode we're in. */ 621 switch (mode) { 622 case IEEE1284_MODE_NIBBLE: 623 case IEEE1284_MODE_BYTE: 624 parport_negotiate (port, IEEE1284_MODE_COMPAT); 625 case IEEE1284_MODE_COMPAT: 626 DPRINTK (KERN_DEBUG "%s: Using compatibility mode\n", 627 port->name); 628 fn = port->ops->compat_write_data; 629 break; 630 631 case IEEE1284_MODE_EPP: 632 DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name); 633 if (addr) { 634 fn = port->ops->epp_write_addr; 635 } else { 636 fn = port->ops->epp_write_data; 637 } 638 break; 639 case IEEE1284_MODE_EPPSWE: 640 DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n", 641 port->name); 642 if (addr) { 643 fn = parport_ieee1284_epp_write_addr; 644 } else { 645 fn = parport_ieee1284_epp_write_data; 646 } 647 break; 648 case IEEE1284_MODE_ECP: 649 case IEEE1284_MODE_ECPRLE: 650 DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name); 651 if (addr) { 652 fn = port->ops->ecp_write_addr; 653 } else { 654 fn = port->ops->ecp_write_data; 655 } 656 break; 657 658 case IEEE1284_MODE_ECPSWE: 659 DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n", 660 port->name); 661 /* The caller has specified that it must be emulated, 662 * even if we have ECP hardware! */ 663 if (addr) { 664 fn = parport_ieee1284_ecp_write_addr; 665 } else { 666 fn = parport_ieee1284_ecp_write_data; 667 } 668 break; 669 670 default: 671 DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name, 672 port->ieee1284.mode); 673 return -ENOSYS; 674 } 675 676 retval = (*fn) (port, buffer, len, 0); 677 DPRINTK (KERN_DEBUG "%s: wrote %d/%d bytes\n", port->name, retval, len); 678 return retval; 679 #endif /* IEEE1284 support */ 680 } 681 682 /** 683 * parport_read - read a block of data from a parallel port 684 * @port: port to read from 685 * @buffer: data buffer (in kernel space) 686 * @len: number of bytes of data to transfer 687 * 688 * This will read up to @len bytes of @buffer to the port 689 * specified, using the IEEE 1284 transfer mode most recently 690 * negotiated to (using parport_negotiate()), as long as that 691 * mode supports reverse transfers (peripheral to host). 692 * 693 * It is the caller's responsibility to ensure that the first 694 * @len bytes of @buffer are available to write to. 695 * 696 * This function returns the number of bytes transferred (if zero 697 * or positive), or else an error code. 698 */ 699 700 ssize_t parport_read (struct parport *port, void *buffer, size_t len) 701 { 702 #ifndef CONFIG_PARPORT_1284 703 printk (KERN_ERR "parport: IEEE1284 not supported in this kernel\n"); 704 return -ENODEV; 705 #else 706 int mode = port->physport->ieee1284.mode; 707 int addr = mode & IEEE1284_ADDR; 708 size_t (*fn) (struct parport *, void *, size_t, int); 709 710 /* Ignore the device-ID-request bit and the address bit. */ 711 mode &= ~(IEEE1284_DEVICEID | IEEE1284_ADDR); 712 713 /* Use the mode we're in. */ 714 switch (mode) { 715 case IEEE1284_MODE_COMPAT: 716 /* if we can tri-state use BYTE mode instead of NIBBLE mode, 717 * if that fails, revert to NIBBLE mode -- ought to store somewhere 718 * the device's ability to do BYTE mode reverse transfers, so we don't 719 * end up needlessly calling negotiate(BYTE) repeately.. (fb) 720 */ 721 if ((port->physport->modes & PARPORT_MODE_TRISTATE) && 722 !parport_negotiate (port, IEEE1284_MODE_BYTE)) { 723 /* got into BYTE mode OK */ 724 DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name); 725 fn = port->ops->byte_read_data; 726 break; 727 } 728 if (parport_negotiate (port, IEEE1284_MODE_NIBBLE)) { 729 return -EIO; 730 } 731 /* fall through to NIBBLE */ 732 case IEEE1284_MODE_NIBBLE: 733 DPRINTK (KERN_DEBUG "%s: Using nibble mode\n", port->name); 734 fn = port->ops->nibble_read_data; 735 break; 736 737 case IEEE1284_MODE_BYTE: 738 DPRINTK (KERN_DEBUG "%s: Using byte mode\n", port->name); 739 fn = port->ops->byte_read_data; 740 break; 741 742 case IEEE1284_MODE_EPP: 743 DPRINTK (KERN_DEBUG "%s: Using EPP mode\n", port->name); 744 if (addr) { 745 fn = port->ops->epp_read_addr; 746 } else { 747 fn = port->ops->epp_read_data; 748 } 749 break; 750 case IEEE1284_MODE_EPPSWE: 751 DPRINTK (KERN_DEBUG "%s: Using software-emulated EPP mode\n", 752 port->name); 753 if (addr) { 754 fn = parport_ieee1284_epp_read_addr; 755 } else { 756 fn = parport_ieee1284_epp_read_data; 757 } 758 break; 759 case IEEE1284_MODE_ECP: 760 case IEEE1284_MODE_ECPRLE: 761 DPRINTK (KERN_DEBUG "%s: Using ECP mode\n", port->name); 762 fn = port->ops->ecp_read_data; 763 break; 764 765 case IEEE1284_MODE_ECPSWE: 766 DPRINTK (KERN_DEBUG "%s: Using software-emulated ECP mode\n", 767 port->name); 768 fn = parport_ieee1284_ecp_read_data; 769 break; 770 771 default: 772 DPRINTK (KERN_DEBUG "%s: Unknown mode 0x%02x\n", port->name, 773 port->physport->ieee1284.mode); 774 return -ENOSYS; 775 } 776 777 return (*fn) (port, buffer, len, 0); 778 #endif /* IEEE1284 support */ 779 } 780 781 /** 782 * parport_set_timeout - set the inactivity timeout for a device 783 * @dev: device on a port 784 * @inactivity: inactivity timeout (in jiffies) 785 * 786 * This sets the inactivity timeout for a particular device on a 787 * port. This affects functions like parport_wait_peripheral(). 788 * The special value 0 means not to call schedule() while dealing 789 * with this device. 790 * 791 * The return value is the previous inactivity timeout. 792 * 793 * Any callers of parport_wait_event() for this device are woken 794 * up. 795 */ 796 797 long parport_set_timeout (struct pardevice *dev, long inactivity) 798 { 799 long int old = dev->timeout; 800 801 dev->timeout = inactivity; 802 803 if (dev->port->physport->cad == dev) 804 parport_ieee1284_wakeup (dev->port); 805 806 return old; 807 } 808 809 /* Exported symbols for modules. */ 810 811 EXPORT_SYMBOL(parport_negotiate); 812 EXPORT_SYMBOL(parport_write); 813 EXPORT_SYMBOL(parport_read); 814 EXPORT_SYMBOL(parport_wait_peripheral); 815 EXPORT_SYMBOL(parport_wait_event); 816 EXPORT_SYMBOL(parport_set_timeout); 817 EXPORT_SYMBOL(parport_ieee1284_interrupt); 818