1 /* 2 * 6522 Versatile Interface Adapter (VIA) 3 * 4 * There are two of these on the Mac II. Some IRQs are vectored 5 * via them as are assorted bits and bobs - eg RTC, ADB. 6 * 7 * CSA: Motorola seems to have removed documentation on the 6522 from 8 * their web site; try 9 * http://nerini.drf.com/vectrex/other/text/chips/6522/ 10 * http://www.zymurgy.net/classic/vic20/vicdet1.htm 11 * and 12 * http://193.23.168.87/mikro_laborversuche/via_iobaustein/via6522_1.html 13 * for info. A full-text web search on 6522 AND VIA will probably also 14 * net some usefulness. <cananian@alumni.princeton.edu> 20apr1999 15 * 16 * Additional data is here (the SY6522 was used in the Mac II etc): 17 * http://www.6502.org/documents/datasheets/synertek/synertek_sy6522.pdf 18 * http://www.6502.org/documents/datasheets/synertek/synertek_sy6522_programming_reference.pdf 19 * 20 * PRAM/RTC access algorithms are from the NetBSD RTC toolkit version 1.08b 21 * by Erik Vogan and adapted to Linux by Joshua M. Thompson (funaho@jurai.org) 22 * 23 */ 24 25 #include <linux/types.h> 26 #include <linux/kernel.h> 27 #include <linux/mm.h> 28 #include <linux/delay.h> 29 #include <linux/init.h> 30 #include <linux/module.h> 31 #include <linux/irq.h> 32 33 #include <asm/macintosh.h> 34 #include <asm/macints.h> 35 #include <asm/mac_via.h> 36 #include <asm/mac_psc.h> 37 #include <asm/mac_oss.h> 38 39 volatile __u8 *via1, *via2; 40 int rbv_present; 41 int via_alt_mapping; 42 EXPORT_SYMBOL(via_alt_mapping); 43 static __u8 rbv_clear; 44 45 /* 46 * Globals for accessing the VIA chip registers without having to 47 * check if we're hitting a real VIA or an RBV. Normally you could 48 * just hit the combined register (ie, vIER|rIER) but that seems to 49 * break on AV Macs...probably because they actually decode more than 50 * eight address bits. Why can't Apple engineers at least be 51 * _consistently_ lazy? - 1999-05-21 (jmt) 52 */ 53 54 static int gIER,gIFR,gBufA,gBufB; 55 56 /* 57 * Timer defs. 58 */ 59 60 #define TICK_SIZE 10000 61 #define MAC_CLOCK_TICK (783300/HZ) /* ticks per HZ */ 62 #define MAC_CLOCK_LOW (MAC_CLOCK_TICK&0xFF) 63 #define MAC_CLOCK_HIGH (MAC_CLOCK_TICK>>8) 64 65 66 /* 67 * On Macs with a genuine VIA chip there is no way to mask an individual slot 68 * interrupt. This limitation also seems to apply to VIA clone logic cores in 69 * Quadra-like ASICs. (RBV and OSS machines don't have this limitation.) 70 * 71 * We used to fake it by configuring the relevant VIA pin as an output 72 * (to mask the interrupt) or input (to unmask). That scheme did not work on 73 * (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector 74 * circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE, 75 * p. 10-11 etc) but VIA outputs are not (see datasheet). 76 * 77 * Driving these outputs high must cause the VIA to source current and the 78 * card to sink current when it asserts /NMRQ. Current will flow but the pin 79 * voltage is uncertain and so the /NMRQ condition may still cause a transition 80 * at the VIA2 CA1 input (which explains the lost interrupts). A side effect 81 * is that a disabled slot IRQ can never be tested as pending or not. 82 * 83 * Driving these outputs low doesn't work either. All the slot /NMRQ lines are 84 * (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see 85 * The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a 86 * disabled /NMRQ line low, the falling edge immediately triggers a CA1 87 * interrupt and all slot interrupts after that will generate no transition 88 * and therefore no interrupt, even after being re-enabled. 89 * 90 * So we make the VIA port A I/O lines inputs and use nubus_disabled to keep 91 * track of their states. When any slot IRQ becomes disabled we mask the CA1 92 * umbrella interrupt. Only when all slot IRQs become enabled do we unmask 93 * the CA1 interrupt. It must remain enabled even when cards have no interrupt 94 * handler registered. Drivers must therefore disable a slot interrupt at the 95 * device before they call free_irq (like shared and autovector interrupts). 96 * 97 * There is also a related problem when MacOS is used to boot Linux. A network 98 * card brought up by a MacOS driver may raise an interrupt while Linux boots. 99 * This can be fatal since it can't be handled until the right driver loads 100 * (if such a driver exists at all). Apparently related to this hardware 101 * limitation, "Designing Cards and Drivers", p. 9-8, says that a slot 102 * interrupt with no driver would crash MacOS (the book was written before 103 * the appearance of Macs with RBV or OSS). 104 */ 105 106 static u8 nubus_disabled; 107 108 void via_debug_dump(void); 109 static void via_nubus_init(void); 110 111 /* 112 * Initialize the VIAs 113 * 114 * First we figure out where they actually _are_ as well as what type of 115 * VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.) 116 * Then we pretty much clear them out and disable all IRQ sources. 117 */ 118 119 void __init via_init(void) 120 { 121 via1 = (void *)VIA1_BASE; 122 pr_debug("VIA1 detected at %p\n", via1); 123 124 if (oss_present) { 125 via2 = NULL; 126 rbv_present = 0; 127 } else { 128 switch (macintosh_config->via_type) { 129 130 /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */ 131 132 case MAC_VIA_IICI: 133 via2 = (void *)RBV_BASE; 134 pr_debug("VIA2 (RBV) detected at %p\n", via2); 135 rbv_present = 1; 136 if (macintosh_config->ident == MAC_MODEL_LCIII) { 137 rbv_clear = 0x00; 138 } else { 139 /* on most RBVs (& unlike the VIAs), you */ 140 /* need to set bit 7 when you write to IFR */ 141 /* in order for your clear to occur. */ 142 rbv_clear = 0x80; 143 } 144 gIER = rIER; 145 gIFR = rIFR; 146 gBufA = rSIFR; 147 gBufB = rBufB; 148 break; 149 150 /* Quadra and early MacIIs agree on the VIA locations */ 151 152 case MAC_VIA_QUADRA: 153 case MAC_VIA_II: 154 via2 = (void *) VIA2_BASE; 155 pr_debug("VIA2 detected at %p\n", via2); 156 rbv_present = 0; 157 rbv_clear = 0x00; 158 gIER = vIER; 159 gIFR = vIFR; 160 gBufA = vBufA; 161 gBufB = vBufB; 162 break; 163 164 default: 165 panic("UNKNOWN VIA TYPE"); 166 } 167 } 168 169 #ifdef DEBUG_VIA 170 via_debug_dump(); 171 #endif 172 173 /* 174 * Shut down all IRQ sources, reset the timers, and 175 * kill the timer latch on VIA1. 176 */ 177 178 via1[vIER] = 0x7F; 179 via1[vIFR] = 0x7F; 180 via1[vT1LL] = 0; 181 via1[vT1LH] = 0; 182 via1[vT1CL] = 0; 183 via1[vT1CH] = 0; 184 via1[vT2CL] = 0; 185 via1[vT2CH] = 0; 186 via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 187 via1[vACR] &= ~0x03; /* disable port A & B latches */ 188 189 /* 190 * SE/30: disable video IRQ 191 * XXX: testing for SE/30 VBL 192 */ 193 194 if (macintosh_config->ident == MAC_MODEL_SE30) { 195 via1[vDirB] |= 0x40; 196 via1[vBufB] |= 0x40; 197 } 198 199 /* 200 * Set the RTC bits to a known state: all lines to outputs and 201 * RTC disabled (yes that's 0 to enable and 1 to disable). 202 */ 203 204 via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData); 205 via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk); 206 207 /* Everything below this point is VIA2/RBV only... */ 208 209 if (oss_present) 210 return; 211 212 if ((macintosh_config->via_type == MAC_VIA_QUADRA) && 213 (macintosh_config->adb_type != MAC_ADB_PB1) && 214 (macintosh_config->adb_type != MAC_ADB_PB2) && 215 (macintosh_config->ident != MAC_MODEL_C660) && 216 (macintosh_config->ident != MAC_MODEL_Q840)) { 217 via_alt_mapping = 1; 218 via1[vDirB] |= 0x40; 219 via1[vBufB] &= ~0x40; 220 } else { 221 via_alt_mapping = 0; 222 } 223 224 /* 225 * Now initialize VIA2. For RBV we just kill all interrupts; 226 * for a regular VIA we also reset the timers and stuff. 227 */ 228 229 via2[gIER] = 0x7F; 230 via2[gIFR] = 0x7F | rbv_clear; 231 if (!rbv_present) { 232 via2[vT1LL] = 0; 233 via2[vT1LH] = 0; 234 via2[vT1CL] = 0; 235 via2[vT1CH] = 0; 236 via2[vT2CL] = 0; 237 via2[vT2CH] = 0; 238 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 239 via2[vACR] &= ~0x03; /* disable port A & B latches */ 240 } 241 242 via_nubus_init(); 243 244 /* Everything below this point is VIA2 only... */ 245 246 if (rbv_present) 247 return; 248 249 /* 250 * Set vPCR for control line interrupts. 251 * 252 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger. 253 * 254 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt. 255 * Testing reveals that PowerBooks do too. However, the SE/30 256 * schematic diagram shows an active high NCR5380 IRQ line. 257 */ 258 259 pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]); 260 if (macintosh_config->via_type == MAC_VIA_II) { 261 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */ 262 via2[vPCR] = 0x66; 263 } else { 264 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */ 265 via2[vPCR] = 0x22; 266 } 267 } 268 269 /* 270 * Start the 100 Hz clock 271 */ 272 273 void __init via_init_clock(irq_handler_t func) 274 { 275 via1[vACR] |= 0x40; 276 via1[vT1LL] = MAC_CLOCK_LOW; 277 via1[vT1LH] = MAC_CLOCK_HIGH; 278 via1[vT1CL] = MAC_CLOCK_LOW; 279 via1[vT1CH] = MAC_CLOCK_HIGH; 280 281 if (request_irq(IRQ_MAC_TIMER_1, func, 0, "timer", func)) 282 pr_err("Couldn't register %s interrupt\n", "timer"); 283 } 284 285 /* 286 * Debugging dump, used in various places to see what's going on. 287 */ 288 289 void via_debug_dump(void) 290 { 291 printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 292 (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]); 293 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 294 (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]); 295 if (!via2) 296 return; 297 if (rbv_present) { 298 printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n", 299 (uint) via2[rIFR], (uint) via2[rIER]); 300 printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n", 301 (uint) via2[rSIFR], (uint) via2[rSIER]); 302 } else { 303 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 304 (uint) via2[vDirA], (uint) via2[vDirB], 305 (uint) via2[vACR]); 306 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 307 (uint) via2[vPCR], 308 (uint) via2[vIFR], (uint) via2[vIER]); 309 } 310 } 311 312 /* 313 * This is always executed with interrupts disabled. 314 * 315 * TBI: get time offset between scheduling timer ticks 316 */ 317 318 u32 mac_gettimeoffset(void) 319 { 320 unsigned long ticks, offset = 0; 321 322 /* read VIA1 timer 2 current value */ 323 ticks = via1[vT1CL] | (via1[vT1CH] << 8); 324 /* The probability of underflow is less than 2% */ 325 if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50) 326 /* Check for pending timer interrupt in VIA1 IFR */ 327 if (via1[vIFR] & 0x40) offset = TICK_SIZE; 328 329 ticks = MAC_CLOCK_TICK - ticks; 330 ticks = ticks * 10000L / MAC_CLOCK_TICK; 331 332 return (ticks + offset) * 1000; 333 } 334 335 /* 336 * Flush the L2 cache on Macs that have it by flipping 337 * the system into 24-bit mode for an instant. 338 */ 339 340 void via_flush_cache(void) 341 { 342 via2[gBufB] &= ~VIA2B_vMode32; 343 via2[gBufB] |= VIA2B_vMode32; 344 } 345 346 /* 347 * Return the status of the L2 cache on a IIci 348 */ 349 350 int via_get_cache_disable(void) 351 { 352 /* Safeguard against being called accidentally */ 353 if (!via2) { 354 printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n"); 355 return 1; 356 } 357 358 return (int) via2[gBufB] & VIA2B_vCDis; 359 } 360 361 /* 362 * Initialize VIA2 for Nubus access 363 */ 364 365 static void __init via_nubus_init(void) 366 { 367 /* unlock nubus transactions */ 368 369 if ((macintosh_config->adb_type != MAC_ADB_PB1) && 370 (macintosh_config->adb_type != MAC_ADB_PB2)) { 371 /* set the line to be an output on non-RBV machines */ 372 if (!rbv_present) 373 via2[vDirB] |= 0x02; 374 375 /* this seems to be an ADB bit on PMU machines */ 376 /* according to MkLinux. -- jmt */ 377 via2[gBufB] |= 0x02; 378 } 379 380 /* 381 * Disable the slot interrupts. On some hardware that's not possible. 382 * On some hardware it's unclear what all of these I/O lines do. 383 */ 384 385 switch (macintosh_config->via_type) { 386 case MAC_VIA_II: 387 case MAC_VIA_QUADRA: 388 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]); 389 break; 390 case MAC_VIA_IICI: 391 /* RBV. Disable all the slot interrupts. SIER works like IER. */ 392 via2[rSIER] = 0x7F; 393 break; 394 } 395 } 396 397 void via_nubus_irq_startup(int irq) 398 { 399 int irq_idx = IRQ_IDX(irq); 400 401 switch (macintosh_config->via_type) { 402 case MAC_VIA_II: 403 case MAC_VIA_QUADRA: 404 /* Make the port A line an input. Probably redundant. */ 405 if (macintosh_config->via_type == MAC_VIA_II) { 406 /* The top two bits are RAM size outputs. */ 407 via2[vDirA] &= 0xC0 | ~(1 << irq_idx); 408 } else { 409 /* Allow NuBus slots 9 through F. */ 410 via2[vDirA] &= 0x80 | ~(1 << irq_idx); 411 } 412 /* fall through */ 413 case MAC_VIA_IICI: 414 via_irq_enable(irq); 415 break; 416 } 417 } 418 419 void via_nubus_irq_shutdown(int irq) 420 { 421 switch (macintosh_config->via_type) { 422 case MAC_VIA_II: 423 case MAC_VIA_QUADRA: 424 /* Ensure that the umbrella CA1 interrupt remains enabled. */ 425 via_irq_enable(irq); 426 break; 427 case MAC_VIA_IICI: 428 via_irq_disable(irq); 429 break; 430 } 431 } 432 433 /* 434 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's 435 * via6522.c :-), disable/pending masks added. 436 */ 437 438 void via1_irq(struct irq_desc *desc) 439 { 440 int irq_num; 441 unsigned char irq_bit, events; 442 443 events = via1[vIFR] & via1[vIER] & 0x7F; 444 if (!events) 445 return; 446 447 irq_num = VIA1_SOURCE_BASE; 448 irq_bit = 1; 449 do { 450 if (events & irq_bit) { 451 via1[vIFR] = irq_bit; 452 generic_handle_irq(irq_num); 453 } 454 ++irq_num; 455 irq_bit <<= 1; 456 } while (events >= irq_bit); 457 } 458 459 static void via2_irq(struct irq_desc *desc) 460 { 461 int irq_num; 462 unsigned char irq_bit, events; 463 464 events = via2[gIFR] & via2[gIER] & 0x7F; 465 if (!events) 466 return; 467 468 irq_num = VIA2_SOURCE_BASE; 469 irq_bit = 1; 470 do { 471 if (events & irq_bit) { 472 via2[gIFR] = irq_bit | rbv_clear; 473 generic_handle_irq(irq_num); 474 } 475 ++irq_num; 476 irq_bit <<= 1; 477 } while (events >= irq_bit); 478 } 479 480 /* 481 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the 482 * VIA2 dispatcher as a fast interrupt handler. 483 */ 484 485 static void via_nubus_irq(struct irq_desc *desc) 486 { 487 int slot_irq; 488 unsigned char slot_bit, events; 489 490 events = ~via2[gBufA] & 0x7F; 491 if (rbv_present) 492 events &= via2[rSIER]; 493 else 494 events &= ~via2[vDirA]; 495 if (!events) 496 return; 497 498 do { 499 slot_irq = IRQ_NUBUS_F; 500 slot_bit = 0x40; 501 do { 502 if (events & slot_bit) { 503 events &= ~slot_bit; 504 generic_handle_irq(slot_irq); 505 } 506 --slot_irq; 507 slot_bit >>= 1; 508 } while (events); 509 510 /* clear the CA1 interrupt and make certain there's no more. */ 511 via2[gIFR] = 0x02 | rbv_clear; 512 events = ~via2[gBufA] & 0x7F; 513 if (rbv_present) 514 events &= via2[rSIER]; 515 else 516 events &= ~via2[vDirA]; 517 } while (events); 518 } 519 520 /* 521 * Register the interrupt dispatchers for VIA or RBV machines only. 522 */ 523 524 void __init via_register_interrupts(void) 525 { 526 if (via_alt_mapping) { 527 /* software interrupt */ 528 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 529 /* via1 interrupt */ 530 irq_set_chained_handler(IRQ_AUTO_6, via1_irq); 531 } else { 532 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 533 } 534 irq_set_chained_handler(IRQ_AUTO_2, via2_irq); 535 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq); 536 } 537 538 void via_irq_enable(int irq) { 539 int irq_src = IRQ_SRC(irq); 540 int irq_idx = IRQ_IDX(irq); 541 542 if (irq_src == 1) { 543 via1[vIER] = IER_SET_BIT(irq_idx); 544 } else if (irq_src == 2) { 545 if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0) 546 via2[gIER] = IER_SET_BIT(irq_idx); 547 } else if (irq_src == 7) { 548 switch (macintosh_config->via_type) { 549 case MAC_VIA_II: 550 case MAC_VIA_QUADRA: 551 nubus_disabled &= ~(1 << irq_idx); 552 /* Enable the CA1 interrupt when no slot is disabled. */ 553 if (!nubus_disabled) 554 via2[gIER] = IER_SET_BIT(1); 555 break; 556 case MAC_VIA_IICI: 557 /* On RBV, enable the slot interrupt. 558 * SIER works like IER. 559 */ 560 via2[rSIER] = IER_SET_BIT(irq_idx); 561 break; 562 } 563 } 564 } 565 566 void via_irq_disable(int irq) { 567 int irq_src = IRQ_SRC(irq); 568 int irq_idx = IRQ_IDX(irq); 569 570 if (irq_src == 1) { 571 via1[vIER] = IER_CLR_BIT(irq_idx); 572 } else if (irq_src == 2) { 573 via2[gIER] = IER_CLR_BIT(irq_idx); 574 } else if (irq_src == 7) { 575 switch (macintosh_config->via_type) { 576 case MAC_VIA_II: 577 case MAC_VIA_QUADRA: 578 nubus_disabled |= 1 << irq_idx; 579 if (nubus_disabled) 580 via2[gIER] = IER_CLR_BIT(1); 581 break; 582 case MAC_VIA_IICI: 583 via2[rSIER] = IER_CLR_BIT(irq_idx); 584 break; 585 } 586 } 587 } 588 589 void via1_set_head(int head) 590 { 591 if (head == 0) 592 via1[vBufA] &= ~VIA1A_vHeadSel; 593 else 594 via1[vBufA] |= VIA1A_vHeadSel; 595 } 596 EXPORT_SYMBOL(via1_set_head); 597 598 int via2_scsi_drq_pending(void) 599 { 600 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ)); 601 } 602 EXPORT_SYMBOL(via2_scsi_drq_pending); 603