1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * 6522 Versatile Interface Adapter (VIA) 4 * 5 * There are two of these on the Mac II. Some IRQs are vectored 6 * via them as are assorted bits and bobs - eg RTC, ADB. 7 * 8 * CSA: Motorola seems to have removed documentation on the 6522 from 9 * their web site; try 10 * http://nerini.drf.com/vectrex/other/text/chips/6522/ 11 * http://www.zymurgy.net/classic/vic20/vicdet1.htm 12 * and 13 * http://193.23.168.87/mikro_laborversuche/via_iobaustein/via6522_1.html 14 * for info. A full-text web search on 6522 AND VIA will probably also 15 * net some usefulness. <cananian@alumni.princeton.edu> 20apr1999 16 * 17 * Additional data is here (the SY6522 was used in the Mac II etc): 18 * http://www.6502.org/documents/datasheets/synertek/synertek_sy6522.pdf 19 * http://www.6502.org/documents/datasheets/synertek/synertek_sy6522_programming_reference.pdf 20 * 21 * PRAM/RTC access algorithms are from the NetBSD RTC toolkit version 1.08b 22 * by Erik Vogan and adapted to Linux by Joshua M. Thompson (funaho@jurai.org) 23 * 24 */ 25 26 #include <linux/types.h> 27 #include <linux/kernel.h> 28 #include <linux/mm.h> 29 #include <linux/delay.h> 30 #include <linux/init.h> 31 #include <linux/module.h> 32 #include <linux/irq.h> 33 34 #include <asm/macintosh.h> 35 #include <asm/macints.h> 36 #include <asm/mac_via.h> 37 #include <asm/mac_psc.h> 38 #include <asm/mac_oss.h> 39 40 volatile __u8 *via1, *via2; 41 int rbv_present; 42 int via_alt_mapping; 43 EXPORT_SYMBOL(via_alt_mapping); 44 static __u8 rbv_clear; 45 46 /* 47 * Globals for accessing the VIA chip registers without having to 48 * check if we're hitting a real VIA or an RBV. Normally you could 49 * just hit the combined register (ie, vIER|rIER) but that seems to 50 * break on AV Macs...probably because they actually decode more than 51 * eight address bits. Why can't Apple engineers at least be 52 * _consistently_ lazy? - 1999-05-21 (jmt) 53 */ 54 55 static int gIER,gIFR,gBufA,gBufB; 56 57 /* 58 * Timer defs. 59 */ 60 61 #define TICK_SIZE 10000 62 #define MAC_CLOCK_TICK (783300/HZ) /* ticks per HZ */ 63 #define MAC_CLOCK_LOW (MAC_CLOCK_TICK&0xFF) 64 #define MAC_CLOCK_HIGH (MAC_CLOCK_TICK>>8) 65 66 67 /* 68 * On Macs with a genuine VIA chip there is no way to mask an individual slot 69 * interrupt. This limitation also seems to apply to VIA clone logic cores in 70 * Quadra-like ASICs. (RBV and OSS machines don't have this limitation.) 71 * 72 * We used to fake it by configuring the relevant VIA pin as an output 73 * (to mask the interrupt) or input (to unmask). That scheme did not work on 74 * (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector 75 * circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE, 76 * p. 10-11 etc) but VIA outputs are not (see datasheet). 77 * 78 * Driving these outputs high must cause the VIA to source current and the 79 * card to sink current when it asserts /NMRQ. Current will flow but the pin 80 * voltage is uncertain and so the /NMRQ condition may still cause a transition 81 * at the VIA2 CA1 input (which explains the lost interrupts). A side effect 82 * is that a disabled slot IRQ can never be tested as pending or not. 83 * 84 * Driving these outputs low doesn't work either. All the slot /NMRQ lines are 85 * (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see 86 * The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a 87 * disabled /NMRQ line low, the falling edge immediately triggers a CA1 88 * interrupt and all slot interrupts after that will generate no transition 89 * and therefore no interrupt, even after being re-enabled. 90 * 91 * So we make the VIA port A I/O lines inputs and use nubus_disabled to keep 92 * track of their states. When any slot IRQ becomes disabled we mask the CA1 93 * umbrella interrupt. Only when all slot IRQs become enabled do we unmask 94 * the CA1 interrupt. It must remain enabled even when cards have no interrupt 95 * handler registered. Drivers must therefore disable a slot interrupt at the 96 * device before they call free_irq (like shared and autovector interrupts). 97 * 98 * There is also a related problem when MacOS is used to boot Linux. A network 99 * card brought up by a MacOS driver may raise an interrupt while Linux boots. 100 * This can be fatal since it can't be handled until the right driver loads 101 * (if such a driver exists at all). Apparently related to this hardware 102 * limitation, "Designing Cards and Drivers", p. 9-8, says that a slot 103 * interrupt with no driver would crash MacOS (the book was written before 104 * the appearance of Macs with RBV or OSS). 105 */ 106 107 static u8 nubus_disabled; 108 109 void via_debug_dump(void); 110 static void via_nubus_init(void); 111 112 /* 113 * Initialize the VIAs 114 * 115 * First we figure out where they actually _are_ as well as what type of 116 * VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.) 117 * Then we pretty much clear them out and disable all IRQ sources. 118 */ 119 120 void __init via_init(void) 121 { 122 via1 = (void *)VIA1_BASE; 123 pr_debug("VIA1 detected at %p\n", via1); 124 125 if (oss_present) { 126 via2 = NULL; 127 rbv_present = 0; 128 } else { 129 switch (macintosh_config->via_type) { 130 131 /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */ 132 133 case MAC_VIA_IICI: 134 via2 = (void *)RBV_BASE; 135 pr_debug("VIA2 (RBV) detected at %p\n", via2); 136 rbv_present = 1; 137 if (macintosh_config->ident == MAC_MODEL_LCIII) { 138 rbv_clear = 0x00; 139 } else { 140 /* on most RBVs (& unlike the VIAs), you */ 141 /* need to set bit 7 when you write to IFR */ 142 /* in order for your clear to occur. */ 143 rbv_clear = 0x80; 144 } 145 gIER = rIER; 146 gIFR = rIFR; 147 gBufA = rSIFR; 148 gBufB = rBufB; 149 break; 150 151 /* Quadra and early MacIIs agree on the VIA locations */ 152 153 case MAC_VIA_QUADRA: 154 case MAC_VIA_II: 155 via2 = (void *) VIA2_BASE; 156 pr_debug("VIA2 detected at %p\n", via2); 157 rbv_present = 0; 158 rbv_clear = 0x00; 159 gIER = vIER; 160 gIFR = vIFR; 161 gBufA = vBufA; 162 gBufB = vBufB; 163 break; 164 165 default: 166 panic("UNKNOWN VIA TYPE"); 167 } 168 } 169 170 #ifdef DEBUG_VIA 171 via_debug_dump(); 172 #endif 173 174 /* 175 * Shut down all IRQ sources, reset the timers, and 176 * kill the timer latch on VIA1. 177 */ 178 179 via1[vIER] = 0x7F; 180 via1[vIFR] = 0x7F; 181 via1[vT1LL] = 0; 182 via1[vT1LH] = 0; 183 via1[vT1CL] = 0; 184 via1[vT1CH] = 0; 185 via1[vT2CL] = 0; 186 via1[vT2CH] = 0; 187 via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 188 via1[vACR] &= ~0x03; /* disable port A & B latches */ 189 190 /* 191 * SE/30: disable video IRQ 192 */ 193 194 if (macintosh_config->ident == MAC_MODEL_SE30) { 195 via1[vDirB] |= 0x40; 196 via1[vBufB] |= 0x40; 197 } 198 199 switch (macintosh_config->adb_type) { 200 case MAC_ADB_IOP: 201 case MAC_ADB_II: 202 case MAC_ADB_PB1: 203 /* 204 * Set the RTC bits to a known state: all lines to outputs and 205 * RTC disabled (yes that's 0 to enable and 1 to disable). 206 */ 207 via1[vDirB] |= VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData; 208 via1[vBufB] |= VIA1B_vRTCEnb | VIA1B_vRTCClk; 209 break; 210 } 211 212 /* Everything below this point is VIA2/RBV only... */ 213 214 if (oss_present) 215 return; 216 217 if ((macintosh_config->via_type == MAC_VIA_QUADRA) && 218 (macintosh_config->adb_type != MAC_ADB_PB1) && 219 (macintosh_config->adb_type != MAC_ADB_PB2) && 220 (macintosh_config->ident != MAC_MODEL_C660) && 221 (macintosh_config->ident != MAC_MODEL_Q840)) { 222 via_alt_mapping = 1; 223 via1[vDirB] |= 0x40; 224 via1[vBufB] &= ~0x40; 225 } else { 226 via_alt_mapping = 0; 227 } 228 229 /* 230 * Now initialize VIA2. For RBV we just kill all interrupts; 231 * for a regular VIA we also reset the timers and stuff. 232 */ 233 234 via2[gIER] = 0x7F; 235 via2[gIFR] = 0x7F | rbv_clear; 236 if (!rbv_present) { 237 via2[vT1LL] = 0; 238 via2[vT1LH] = 0; 239 via2[vT1CL] = 0; 240 via2[vT1CH] = 0; 241 via2[vT2CL] = 0; 242 via2[vT2CH] = 0; 243 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 244 via2[vACR] &= ~0x03; /* disable port A & B latches */ 245 } 246 247 via_nubus_init(); 248 249 /* Everything below this point is VIA2 only... */ 250 251 if (rbv_present) 252 return; 253 254 /* 255 * Set vPCR for control line interrupts. 256 * 257 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger. 258 * 259 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt. 260 * Testing reveals that PowerBooks do too. However, the SE/30 261 * schematic diagram shows an active high NCR5380 IRQ line. 262 */ 263 264 pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]); 265 if (macintosh_config->via_type == MAC_VIA_II) { 266 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */ 267 via2[vPCR] = 0x66; 268 } else { 269 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */ 270 via2[vPCR] = 0x22; 271 } 272 } 273 274 /* 275 * Start the 100 Hz clock 276 */ 277 278 void __init via_init_clock(irq_handler_t func) 279 { 280 via1[vACR] |= 0x40; 281 via1[vT1LL] = MAC_CLOCK_LOW; 282 via1[vT1LH] = MAC_CLOCK_HIGH; 283 via1[vT1CL] = MAC_CLOCK_LOW; 284 via1[vT1CH] = MAC_CLOCK_HIGH; 285 286 if (request_irq(IRQ_MAC_TIMER_1, func, 0, "timer", func)) 287 pr_err("Couldn't register %s interrupt\n", "timer"); 288 } 289 290 /* 291 * Debugging dump, used in various places to see what's going on. 292 */ 293 294 void via_debug_dump(void) 295 { 296 printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 297 (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]); 298 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 299 (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]); 300 if (!via2) 301 return; 302 if (rbv_present) { 303 printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n", 304 (uint) via2[rIFR], (uint) via2[rIER]); 305 printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n", 306 (uint) via2[rSIFR], (uint) via2[rSIER]); 307 } else { 308 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 309 (uint) via2[vDirA], (uint) via2[vDirB], 310 (uint) via2[vACR]); 311 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 312 (uint) via2[vPCR], 313 (uint) via2[vIFR], (uint) via2[vIER]); 314 } 315 } 316 317 /* 318 * This is always executed with interrupts disabled. 319 * 320 * TBI: get time offset between scheduling timer ticks 321 */ 322 323 u32 mac_gettimeoffset(void) 324 { 325 unsigned long ticks, offset = 0; 326 327 /* read VIA1 timer 2 current value */ 328 ticks = via1[vT1CL] | (via1[vT1CH] << 8); 329 /* The probability of underflow is less than 2% */ 330 if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50) 331 /* Check for pending timer interrupt in VIA1 IFR */ 332 if (via1[vIFR] & 0x40) offset = TICK_SIZE; 333 334 ticks = MAC_CLOCK_TICK - ticks; 335 ticks = ticks * 10000L / MAC_CLOCK_TICK; 336 337 return (ticks + offset) * 1000; 338 } 339 340 /* 341 * Flush the L2 cache on Macs that have it by flipping 342 * the system into 24-bit mode for an instant. 343 */ 344 345 void via_flush_cache(void) 346 { 347 via2[gBufB] &= ~VIA2B_vMode32; 348 via2[gBufB] |= VIA2B_vMode32; 349 } 350 351 /* 352 * Return the status of the L2 cache on a IIci 353 */ 354 355 int via_get_cache_disable(void) 356 { 357 /* Safeguard against being called accidentally */ 358 if (!via2) { 359 printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n"); 360 return 1; 361 } 362 363 return (int) via2[gBufB] & VIA2B_vCDis; 364 } 365 366 /* 367 * Initialize VIA2 for Nubus access 368 */ 369 370 static void __init via_nubus_init(void) 371 { 372 /* unlock nubus transactions */ 373 374 if ((macintosh_config->adb_type != MAC_ADB_PB1) && 375 (macintosh_config->adb_type != MAC_ADB_PB2)) { 376 /* set the line to be an output on non-RBV machines */ 377 if (!rbv_present) 378 via2[vDirB] |= 0x02; 379 380 /* this seems to be an ADB bit on PMU machines */ 381 /* according to MkLinux. -- jmt */ 382 via2[gBufB] |= 0x02; 383 } 384 385 /* 386 * Disable the slot interrupts. On some hardware that's not possible. 387 * On some hardware it's unclear what all of these I/O lines do. 388 */ 389 390 switch (macintosh_config->via_type) { 391 case MAC_VIA_II: 392 case MAC_VIA_QUADRA: 393 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]); 394 break; 395 case MAC_VIA_IICI: 396 /* RBV. Disable all the slot interrupts. SIER works like IER. */ 397 via2[rSIER] = 0x7F; 398 break; 399 } 400 } 401 402 void via_nubus_irq_startup(int irq) 403 { 404 int irq_idx = IRQ_IDX(irq); 405 406 switch (macintosh_config->via_type) { 407 case MAC_VIA_II: 408 case MAC_VIA_QUADRA: 409 /* Make the port A line an input. Probably redundant. */ 410 if (macintosh_config->via_type == MAC_VIA_II) { 411 /* The top two bits are RAM size outputs. */ 412 via2[vDirA] &= 0xC0 | ~(1 << irq_idx); 413 } else { 414 /* Allow NuBus slots 9 through F. */ 415 via2[vDirA] &= 0x80 | ~(1 << irq_idx); 416 } 417 /* fall through */ 418 case MAC_VIA_IICI: 419 via_irq_enable(irq); 420 break; 421 } 422 } 423 424 void via_nubus_irq_shutdown(int irq) 425 { 426 switch (macintosh_config->via_type) { 427 case MAC_VIA_II: 428 case MAC_VIA_QUADRA: 429 /* Ensure that the umbrella CA1 interrupt remains enabled. */ 430 via_irq_enable(irq); 431 break; 432 case MAC_VIA_IICI: 433 via_irq_disable(irq); 434 break; 435 } 436 } 437 438 /* 439 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's 440 * via6522.c :-), disable/pending masks added. 441 */ 442 443 void via1_irq(struct irq_desc *desc) 444 { 445 int irq_num; 446 unsigned char irq_bit, events; 447 448 events = via1[vIFR] & via1[vIER] & 0x7F; 449 if (!events) 450 return; 451 452 irq_num = VIA1_SOURCE_BASE; 453 irq_bit = 1; 454 do { 455 if (events & irq_bit) { 456 via1[vIFR] = irq_bit; 457 generic_handle_irq(irq_num); 458 } 459 ++irq_num; 460 irq_bit <<= 1; 461 } while (events >= irq_bit); 462 } 463 464 static void via2_irq(struct irq_desc *desc) 465 { 466 int irq_num; 467 unsigned char irq_bit, events; 468 469 events = via2[gIFR] & via2[gIER] & 0x7F; 470 if (!events) 471 return; 472 473 irq_num = VIA2_SOURCE_BASE; 474 irq_bit = 1; 475 do { 476 if (events & irq_bit) { 477 via2[gIFR] = irq_bit | rbv_clear; 478 generic_handle_irq(irq_num); 479 } 480 ++irq_num; 481 irq_bit <<= 1; 482 } while (events >= irq_bit); 483 } 484 485 /* 486 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the 487 * VIA2 dispatcher as a fast interrupt handler. 488 */ 489 490 static void via_nubus_irq(struct irq_desc *desc) 491 { 492 int slot_irq; 493 unsigned char slot_bit, events; 494 495 events = ~via2[gBufA] & 0x7F; 496 if (rbv_present) 497 events &= via2[rSIER]; 498 else 499 events &= ~via2[vDirA]; 500 if (!events) 501 return; 502 503 do { 504 slot_irq = IRQ_NUBUS_F; 505 slot_bit = 0x40; 506 do { 507 if (events & slot_bit) { 508 events &= ~slot_bit; 509 generic_handle_irq(slot_irq); 510 } 511 --slot_irq; 512 slot_bit >>= 1; 513 } while (events); 514 515 /* clear the CA1 interrupt and make certain there's no more. */ 516 via2[gIFR] = 0x02 | rbv_clear; 517 events = ~via2[gBufA] & 0x7F; 518 if (rbv_present) 519 events &= via2[rSIER]; 520 else 521 events &= ~via2[vDirA]; 522 } while (events); 523 } 524 525 /* 526 * Register the interrupt dispatchers for VIA or RBV machines only. 527 */ 528 529 void __init via_register_interrupts(void) 530 { 531 if (via_alt_mapping) { 532 /* software interrupt */ 533 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 534 /* via1 interrupt */ 535 irq_set_chained_handler(IRQ_AUTO_6, via1_irq); 536 } else { 537 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 538 } 539 irq_set_chained_handler(IRQ_AUTO_2, via2_irq); 540 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq); 541 } 542 543 void via_irq_enable(int irq) { 544 int irq_src = IRQ_SRC(irq); 545 int irq_idx = IRQ_IDX(irq); 546 547 if (irq_src == 1) { 548 via1[vIER] = IER_SET_BIT(irq_idx); 549 } else if (irq_src == 2) { 550 if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0) 551 via2[gIER] = IER_SET_BIT(irq_idx); 552 } else if (irq_src == 7) { 553 switch (macintosh_config->via_type) { 554 case MAC_VIA_II: 555 case MAC_VIA_QUADRA: 556 nubus_disabled &= ~(1 << irq_idx); 557 /* Enable the CA1 interrupt when no slot is disabled. */ 558 if (!nubus_disabled) 559 via2[gIER] = IER_SET_BIT(1); 560 break; 561 case MAC_VIA_IICI: 562 /* On RBV, enable the slot interrupt. 563 * SIER works like IER. 564 */ 565 via2[rSIER] = IER_SET_BIT(irq_idx); 566 break; 567 } 568 } 569 } 570 571 void via_irq_disable(int irq) { 572 int irq_src = IRQ_SRC(irq); 573 int irq_idx = IRQ_IDX(irq); 574 575 if (irq_src == 1) { 576 via1[vIER] = IER_CLR_BIT(irq_idx); 577 } else if (irq_src == 2) { 578 via2[gIER] = IER_CLR_BIT(irq_idx); 579 } else if (irq_src == 7) { 580 switch (macintosh_config->via_type) { 581 case MAC_VIA_II: 582 case MAC_VIA_QUADRA: 583 nubus_disabled |= 1 << irq_idx; 584 if (nubus_disabled) 585 via2[gIER] = IER_CLR_BIT(1); 586 break; 587 case MAC_VIA_IICI: 588 via2[rSIER] = IER_CLR_BIT(irq_idx); 589 break; 590 } 591 } 592 } 593 594 void via1_set_head(int head) 595 { 596 if (head == 0) 597 via1[vBufA] &= ~VIA1A_vHeadSel; 598 else 599 via1[vBufA] |= VIA1A_vHeadSel; 600 } 601 EXPORT_SYMBOL(via1_set_head); 602 603 int via2_scsi_drq_pending(void) 604 { 605 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ)); 606 } 607 EXPORT_SYMBOL(via2_scsi_drq_pending); 608