1 /* 2 * IEEE 1284.3 Parallel port daisy chain and multiplexor code 3 * 4 * Copyright (C) 1999, 2000 Tim Waugh <tim@cyberelk.demon.co.uk> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 * ??-12-1998: Initial implementation. 12 * 31-01-1999: Make port-cloning transparent. 13 * 13-02-1999: Move DeviceID technique from parport_probe. 14 * 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too. 15 * 22-02-2000: Count devices that are actually detected. 16 * 17 * Any part of this program may be used in documents licensed under 18 * the GNU Free Documentation License, Version 1.1 or any later version 19 * published by the Free Software Foundation. 20 */ 21 22 #include <linux/module.h> 23 #include <linux/parport.h> 24 #include <linux/delay.h> 25 #include <linux/slab.h> 26 #include <linux/sched/signal.h> 27 28 #include <asm/current.h> 29 #include <linux/uaccess.h> 30 31 #undef DEBUG 32 33 #ifdef DEBUG 34 #define DPRINTK(stuff...) printk(stuff) 35 #else 36 #define DPRINTK(stuff...) 37 #endif 38 39 static struct daisydev { 40 struct daisydev *next; 41 struct parport *port; 42 int daisy; 43 int devnum; 44 } *topology = NULL; 45 static DEFINE_SPINLOCK(topology_lock); 46 47 static int numdevs; 48 static bool daisy_init_done; 49 50 /* Forward-declaration of lower-level functions. */ 51 static int mux_present(struct parport *port); 52 static int num_mux_ports(struct parport *port); 53 static int select_port(struct parport *port); 54 static int assign_addrs(struct parport *port); 55 56 /* Add a device to the discovered topology. */ 57 static void add_dev(int devnum, struct parport *port, int daisy) 58 { 59 struct daisydev *newdev, **p; 60 newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL); 61 if (newdev) { 62 newdev->port = port; 63 newdev->daisy = daisy; 64 newdev->devnum = devnum; 65 spin_lock(&topology_lock); 66 for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next) 67 ; 68 newdev->next = *p; 69 *p = newdev; 70 spin_unlock(&topology_lock); 71 } 72 } 73 74 /* Clone a parport (actually, make an alias). */ 75 static struct parport *clone_parport(struct parport *real, int muxport) 76 { 77 struct parport *extra = parport_register_port(real->base, 78 real->irq, 79 real->dma, 80 real->ops); 81 if (extra) { 82 extra->portnum = real->portnum; 83 extra->physport = real; 84 extra->muxport = muxport; 85 real->slaves[muxport-1] = extra; 86 } 87 88 return extra; 89 } 90 91 static int daisy_drv_probe(struct pardevice *par_dev) 92 { 93 struct device_driver *drv = par_dev->dev.driver; 94 95 if (strcmp(drv->name, "daisy_drv")) 96 return -ENODEV; 97 if (strcmp(par_dev->name, daisy_dev_name)) 98 return -ENODEV; 99 100 return 0; 101 } 102 103 static struct parport_driver daisy_driver = { 104 .name = "daisy_drv", 105 .probe = daisy_drv_probe, 106 .devmodel = true, 107 }; 108 109 /* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains. 110 * Return value is number of devices actually detected. */ 111 int parport_daisy_init(struct parport *port) 112 { 113 int detected = 0; 114 char *deviceid; 115 static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" }; 116 int num_ports; 117 int i; 118 int last_try = 0; 119 120 if (!daisy_init_done) { 121 /* 122 * flag should be marked true first as 123 * parport_register_driver() might try to load the low 124 * level driver which will lead to announcing new ports 125 * and which will again come back here at 126 * parport_daisy_init() 127 */ 128 daisy_init_done = true; 129 i = parport_register_driver(&daisy_driver); 130 if (i) { 131 pr_err("daisy registration failed\n"); 132 daisy_init_done = false; 133 return i; 134 } 135 } 136 137 again: 138 /* Because this is called before any other devices exist, 139 * we don't have to claim exclusive access. */ 140 141 /* If mux present on normal port, need to create new 142 * parports for each extra port. */ 143 if (port->muxport < 0 && mux_present(port) && 144 /* don't be fooled: a mux must have 2 or 4 ports. */ 145 ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) { 146 /* Leave original as port zero. */ 147 port->muxport = 0; 148 printk(KERN_INFO 149 "%s: 1st (default) port of %d-way multiplexor\n", 150 port->name, num_ports); 151 for (i = 1; i < num_ports; i++) { 152 /* Clone the port. */ 153 struct parport *extra = clone_parport(port, i); 154 if (!extra) { 155 if (signal_pending(current)) 156 break; 157 158 schedule(); 159 continue; 160 } 161 162 printk(KERN_INFO 163 "%s: %d%s port of %d-way multiplexor on %s\n", 164 extra->name, i + 1, th[i + 1], num_ports, 165 port->name); 166 167 /* Analyse that port too. We won't recurse 168 forever because of the 'port->muxport < 0' 169 test above. */ 170 parport_daisy_init(extra); 171 } 172 } 173 174 if (port->muxport >= 0) 175 select_port(port); 176 177 parport_daisy_deselect_all(port); 178 detected += assign_addrs(port); 179 180 /* Count the potential legacy device at the end. */ 181 add_dev(numdevs++, port, -1); 182 183 /* Find out the legacy device's IEEE 1284 device ID. */ 184 deviceid = kmalloc(1024, GFP_KERNEL); 185 if (deviceid) { 186 if (parport_device_id(numdevs - 1, deviceid, 1024) > 2) 187 detected++; 188 189 kfree(deviceid); 190 } 191 192 if (!detected && !last_try) { 193 /* No devices were detected. Perhaps they are in some 194 funny state; let's try to reset them and see if 195 they wake up. */ 196 parport_daisy_fini(port); 197 parport_write_control(port, PARPORT_CONTROL_SELECT); 198 udelay(50); 199 parport_write_control(port, 200 PARPORT_CONTROL_SELECT | 201 PARPORT_CONTROL_INIT); 202 udelay(50); 203 last_try = 1; 204 goto again; 205 } 206 207 return detected; 208 } 209 210 /* Forget about devices on a physical port. */ 211 void parport_daisy_fini(struct parport *port) 212 { 213 struct daisydev **p; 214 215 spin_lock(&topology_lock); 216 p = &topology; 217 while (*p) { 218 struct daisydev *dev = *p; 219 if (dev->port != port) { 220 p = &dev->next; 221 continue; 222 } 223 *p = dev->next; 224 kfree(dev); 225 } 226 227 /* Gaps in the numbering could be handled better. How should 228 someone enumerate through all IEEE1284.3 devices in the 229 topology?. */ 230 if (!topology) numdevs = 0; 231 spin_unlock(&topology_lock); 232 return; 233 } 234 235 /** 236 * parport_open - find a device by canonical device number 237 * @devnum: canonical device number 238 * @name: name to associate with the device 239 * 240 * This function is similar to parport_register_device(), except 241 * that it locates a device by its number rather than by the port 242 * it is attached to. 243 * 244 * All parameters except for @devnum are the same as for 245 * parport_register_device(). The return value is the same as 246 * for parport_register_device(). 247 **/ 248 249 struct pardevice *parport_open(int devnum, const char *name) 250 { 251 struct daisydev *p = topology; 252 struct pardev_cb par_cb; 253 struct parport *port; 254 struct pardevice *dev; 255 int daisy; 256 257 memset(&par_cb, 0, sizeof(par_cb)); 258 spin_lock(&topology_lock); 259 while (p && p->devnum != devnum) 260 p = p->next; 261 262 if (!p) { 263 spin_unlock(&topology_lock); 264 return NULL; 265 } 266 267 daisy = p->daisy; 268 port = parport_get_port(p->port); 269 spin_unlock(&topology_lock); 270 271 dev = parport_register_dev_model(port, name, &par_cb, devnum); 272 parport_put_port(port); 273 if (!dev) 274 return NULL; 275 276 dev->daisy = daisy; 277 278 /* Check that there really is a device to select. */ 279 if (daisy >= 0) { 280 int selected; 281 parport_claim_or_block(dev); 282 selected = port->daisy; 283 parport_release(dev); 284 285 if (selected != daisy) { 286 /* No corresponding device. */ 287 parport_unregister_device(dev); 288 return NULL; 289 } 290 } 291 292 return dev; 293 } 294 295 /** 296 * parport_close - close a device opened with parport_open() 297 * @dev: device to close 298 * 299 * This is to parport_open() as parport_unregister_device() is to 300 * parport_register_device(). 301 **/ 302 303 void parport_close(struct pardevice *dev) 304 { 305 parport_unregister_device(dev); 306 } 307 308 /* Send a daisy-chain-style CPP command packet. */ 309 static int cpp_daisy(struct parport *port, int cmd) 310 { 311 unsigned char s; 312 313 parport_data_forward(port); 314 parport_write_data(port, 0xaa); udelay(2); 315 parport_write_data(port, 0x55); udelay(2); 316 parport_write_data(port, 0x00); udelay(2); 317 parport_write_data(port, 0xff); udelay(2); 318 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 319 | PARPORT_STATUS_PAPEROUT 320 | PARPORT_STATUS_SELECT 321 | PARPORT_STATUS_ERROR); 322 if (s != (PARPORT_STATUS_BUSY 323 | PARPORT_STATUS_PAPEROUT 324 | PARPORT_STATUS_SELECT 325 | PARPORT_STATUS_ERROR)) { 326 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n", 327 port->name, s); 328 return -ENXIO; 329 } 330 331 parport_write_data(port, 0x87); udelay(2); 332 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 333 | PARPORT_STATUS_PAPEROUT 334 | PARPORT_STATUS_SELECT 335 | PARPORT_STATUS_ERROR); 336 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) { 337 DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n", 338 port->name, s); 339 return -ENXIO; 340 } 341 342 parport_write_data(port, 0x78); udelay(2); 343 parport_write_data(port, cmd); udelay(2); 344 parport_frob_control(port, 345 PARPORT_CONTROL_STROBE, 346 PARPORT_CONTROL_STROBE); 347 udelay(1); 348 s = parport_read_status(port); 349 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0); 350 udelay(1); 351 parport_write_data(port, 0xff); udelay(2); 352 353 return s; 354 } 355 356 /* Send a mux-style CPP command packet. */ 357 static int cpp_mux(struct parport *port, int cmd) 358 { 359 unsigned char s; 360 int rc; 361 362 parport_data_forward(port); 363 parport_write_data(port, 0xaa); udelay(2); 364 parport_write_data(port, 0x55); udelay(2); 365 parport_write_data(port, 0xf0); udelay(2); 366 parport_write_data(port, 0x0f); udelay(2); 367 parport_write_data(port, 0x52); udelay(2); 368 parport_write_data(port, 0xad); udelay(2); 369 parport_write_data(port, cmd); udelay(2); 370 371 s = parport_read_status(port); 372 if (!(s & PARPORT_STATUS_ACK)) { 373 DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n", 374 port->name, cmd, s); 375 return -EIO; 376 } 377 378 rc = (((s & PARPORT_STATUS_SELECT ? 1 : 0) << 0) | 379 ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) | 380 ((s & PARPORT_STATUS_BUSY ? 0 : 1) << 2) | 381 ((s & PARPORT_STATUS_ERROR ? 0 : 1) << 3)); 382 383 return rc; 384 } 385 386 void parport_daisy_deselect_all(struct parport *port) 387 { 388 cpp_daisy(port, 0x30); 389 } 390 391 int parport_daisy_select(struct parport *port, int daisy, int mode) 392 { 393 switch (mode) 394 { 395 // For these modes we should switch to EPP mode: 396 case IEEE1284_MODE_EPP: 397 case IEEE1284_MODE_EPPSL: 398 case IEEE1284_MODE_EPPSWE: 399 return !(cpp_daisy(port, 0x20 + daisy) & 400 PARPORT_STATUS_ERROR); 401 402 // For these modes we should switch to ECP mode: 403 case IEEE1284_MODE_ECP: 404 case IEEE1284_MODE_ECPRLE: 405 case IEEE1284_MODE_ECPSWE: 406 return !(cpp_daisy(port, 0xd0 + daisy) & 407 PARPORT_STATUS_ERROR); 408 409 // Nothing was told for BECP in Daisy chain specification. 410 // May be it's wise to use ECP? 411 case IEEE1284_MODE_BECP: 412 // Others use compat mode 413 case IEEE1284_MODE_NIBBLE: 414 case IEEE1284_MODE_BYTE: 415 case IEEE1284_MODE_COMPAT: 416 default: 417 return !(cpp_daisy(port, 0xe0 + daisy) & 418 PARPORT_STATUS_ERROR); 419 } 420 } 421 422 static int mux_present(struct parport *port) 423 { 424 return cpp_mux(port, 0x51) == 3; 425 } 426 427 static int num_mux_ports(struct parport *port) 428 { 429 return cpp_mux(port, 0x58); 430 } 431 432 static int select_port(struct parport *port) 433 { 434 int muxport = port->muxport; 435 return cpp_mux(port, 0x60 + muxport) == muxport; 436 } 437 438 static int assign_addrs(struct parport *port) 439 { 440 unsigned char s; 441 unsigned char daisy; 442 int thisdev = numdevs; 443 int detected; 444 char *deviceid; 445 446 parport_data_forward(port); 447 parport_write_data(port, 0xaa); udelay(2); 448 parport_write_data(port, 0x55); udelay(2); 449 parport_write_data(port, 0x00); udelay(2); 450 parport_write_data(port, 0xff); udelay(2); 451 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 452 | PARPORT_STATUS_PAPEROUT 453 | PARPORT_STATUS_SELECT 454 | PARPORT_STATUS_ERROR); 455 if (s != (PARPORT_STATUS_BUSY 456 | PARPORT_STATUS_PAPEROUT 457 | PARPORT_STATUS_SELECT 458 | PARPORT_STATUS_ERROR)) { 459 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n", 460 port->name, s); 461 return 0; 462 } 463 464 parport_write_data(port, 0x87); udelay(2); 465 s = parport_read_status(port) & (PARPORT_STATUS_BUSY 466 | PARPORT_STATUS_PAPEROUT 467 | PARPORT_STATUS_SELECT 468 | PARPORT_STATUS_ERROR); 469 if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) { 470 DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n", 471 port->name, s); 472 return 0; 473 } 474 475 parport_write_data(port, 0x78); udelay(2); 476 s = parport_read_status(port); 477 478 for (daisy = 0; 479 (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)) 480 == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT) 481 && daisy < 4; 482 ++daisy) { 483 parport_write_data(port, daisy); 484 udelay(2); 485 parport_frob_control(port, 486 PARPORT_CONTROL_STROBE, 487 PARPORT_CONTROL_STROBE); 488 udelay(1); 489 parport_frob_control(port, PARPORT_CONTROL_STROBE, 0); 490 udelay(1); 491 492 add_dev(numdevs++, port, daisy); 493 494 /* See if this device thought it was the last in the 495 * chain. */ 496 if (!(s & PARPORT_STATUS_BUSY)) 497 break; 498 499 /* We are seeing pass through status now. We see 500 last_dev from next device or if last_dev does not 501 work status lines from some non-daisy chain 502 device. */ 503 s = parport_read_status(port); 504 } 505 506 parport_write_data(port, 0xff); udelay(2); 507 detected = numdevs - thisdev; 508 DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name, 509 detected); 510 511 /* Ask the new devices to introduce themselves. */ 512 deviceid = kmalloc(1024, GFP_KERNEL); 513 if (!deviceid) return 0; 514 515 for (daisy = 0; thisdev < numdevs; thisdev++, daisy++) 516 parport_device_id(thisdev, deviceid, 1024); 517 518 kfree(deviceid); 519 return detected; 520 } 521