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 * XXX: testing for SE/30 VBL 193 */ 194 195 if (macintosh_config->ident == MAC_MODEL_SE30) { 196 via1[vDirB] |= 0x40; 197 via1[vBufB] |= 0x40; 198 } 199 200 /* 201 * Set the RTC bits to a known state: all lines to outputs and 202 * RTC disabled (yes that's 0 to enable and 1 to disable). 203 */ 204 205 via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData); 206 via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk); 207 208 /* Everything below this point is VIA2/RBV only... */ 209 210 if (oss_present) 211 return; 212 213 if ((macintosh_config->via_type == MAC_VIA_QUADRA) && 214 (macintosh_config->adb_type != MAC_ADB_PB1) && 215 (macintosh_config->adb_type != MAC_ADB_PB2) && 216 (macintosh_config->ident != MAC_MODEL_C660) && 217 (macintosh_config->ident != MAC_MODEL_Q840)) { 218 via_alt_mapping = 1; 219 via1[vDirB] |= 0x40; 220 via1[vBufB] &= ~0x40; 221 } else { 222 via_alt_mapping = 0; 223 } 224 225 /* 226 * Now initialize VIA2. For RBV we just kill all interrupts; 227 * for a regular VIA we also reset the timers and stuff. 228 */ 229 230 via2[gIER] = 0x7F; 231 via2[gIFR] = 0x7F | rbv_clear; 232 if (!rbv_present) { 233 via2[vT1LL] = 0; 234 via2[vT1LH] = 0; 235 via2[vT1CL] = 0; 236 via2[vT1CH] = 0; 237 via2[vT2CL] = 0; 238 via2[vT2CH] = 0; 239 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 240 via2[vACR] &= ~0x03; /* disable port A & B latches */ 241 } 242 243 via_nubus_init(); 244 245 /* Everything below this point is VIA2 only... */ 246 247 if (rbv_present) 248 return; 249 250 /* 251 * Set vPCR for control line interrupts. 252 * 253 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger. 254 * 255 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt. 256 * Testing reveals that PowerBooks do too. However, the SE/30 257 * schematic diagram shows an active high NCR5380 IRQ line. 258 */ 259 260 pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]); 261 if (macintosh_config->via_type == MAC_VIA_II) { 262 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */ 263 via2[vPCR] = 0x66; 264 } else { 265 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */ 266 via2[vPCR] = 0x22; 267 } 268 } 269 270 /* 271 * Start the 100 Hz clock 272 */ 273 274 void __init via_init_clock(irq_handler_t func) 275 { 276 via1[vACR] |= 0x40; 277 via1[vT1LL] = MAC_CLOCK_LOW; 278 via1[vT1LH] = MAC_CLOCK_HIGH; 279 via1[vT1CL] = MAC_CLOCK_LOW; 280 via1[vT1CH] = MAC_CLOCK_HIGH; 281 282 if (request_irq(IRQ_MAC_TIMER_1, func, 0, "timer", func)) 283 pr_err("Couldn't register %s interrupt\n", "timer"); 284 } 285 286 /* 287 * Debugging dump, used in various places to see what's going on. 288 */ 289 290 void via_debug_dump(void) 291 { 292 printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 293 (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]); 294 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 295 (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]); 296 if (!via2) 297 return; 298 if (rbv_present) { 299 printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n", 300 (uint) via2[rIFR], (uint) via2[rIER]); 301 printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n", 302 (uint) via2[rSIFR], (uint) via2[rSIER]); 303 } else { 304 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 305 (uint) via2[vDirA], (uint) via2[vDirB], 306 (uint) via2[vACR]); 307 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 308 (uint) via2[vPCR], 309 (uint) via2[vIFR], (uint) via2[vIER]); 310 } 311 } 312 313 /* 314 * This is always executed with interrupts disabled. 315 * 316 * TBI: get time offset between scheduling timer ticks 317 */ 318 319 u32 mac_gettimeoffset(void) 320 { 321 unsigned long ticks, offset = 0; 322 323 /* read VIA1 timer 2 current value */ 324 ticks = via1[vT1CL] | (via1[vT1CH] << 8); 325 /* The probability of underflow is less than 2% */ 326 if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50) 327 /* Check for pending timer interrupt in VIA1 IFR */ 328 if (via1[vIFR] & 0x40) offset = TICK_SIZE; 329 330 ticks = MAC_CLOCK_TICK - ticks; 331 ticks = ticks * 10000L / MAC_CLOCK_TICK; 332 333 return (ticks + offset) * 1000; 334 } 335 336 /* 337 * Flush the L2 cache on Macs that have it by flipping 338 * the system into 24-bit mode for an instant. 339 */ 340 341 void via_flush_cache(void) 342 { 343 via2[gBufB] &= ~VIA2B_vMode32; 344 via2[gBufB] |= VIA2B_vMode32; 345 } 346 347 /* 348 * Return the status of the L2 cache on a IIci 349 */ 350 351 int via_get_cache_disable(void) 352 { 353 /* Safeguard against being called accidentally */ 354 if (!via2) { 355 printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n"); 356 return 1; 357 } 358 359 return (int) via2[gBufB] & VIA2B_vCDis; 360 } 361 362 /* 363 * Initialize VIA2 for Nubus access 364 */ 365 366 static void __init via_nubus_init(void) 367 { 368 /* unlock nubus transactions */ 369 370 if ((macintosh_config->adb_type != MAC_ADB_PB1) && 371 (macintosh_config->adb_type != MAC_ADB_PB2)) { 372 /* set the line to be an output on non-RBV machines */ 373 if (!rbv_present) 374 via2[vDirB] |= 0x02; 375 376 /* this seems to be an ADB bit on PMU machines */ 377 /* according to MkLinux. -- jmt */ 378 via2[gBufB] |= 0x02; 379 } 380 381 /* 382 * Disable the slot interrupts. On some hardware that's not possible. 383 * On some hardware it's unclear what all of these I/O lines do. 384 */ 385 386 switch (macintosh_config->via_type) { 387 case MAC_VIA_II: 388 case MAC_VIA_QUADRA: 389 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]); 390 break; 391 case MAC_VIA_IICI: 392 /* RBV. Disable all the slot interrupts. SIER works like IER. */ 393 via2[rSIER] = 0x7F; 394 break; 395 } 396 } 397 398 void via_nubus_irq_startup(int irq) 399 { 400 int irq_idx = IRQ_IDX(irq); 401 402 switch (macintosh_config->via_type) { 403 case MAC_VIA_II: 404 case MAC_VIA_QUADRA: 405 /* Make the port A line an input. Probably redundant. */ 406 if (macintosh_config->via_type == MAC_VIA_II) { 407 /* The top two bits are RAM size outputs. */ 408 via2[vDirA] &= 0xC0 | ~(1 << irq_idx); 409 } else { 410 /* Allow NuBus slots 9 through F. */ 411 via2[vDirA] &= 0x80 | ~(1 << irq_idx); 412 } 413 /* fall through */ 414 case MAC_VIA_IICI: 415 via_irq_enable(irq); 416 break; 417 } 418 } 419 420 void via_nubus_irq_shutdown(int irq) 421 { 422 switch (macintosh_config->via_type) { 423 case MAC_VIA_II: 424 case MAC_VIA_QUADRA: 425 /* Ensure that the umbrella CA1 interrupt remains enabled. */ 426 via_irq_enable(irq); 427 break; 428 case MAC_VIA_IICI: 429 via_irq_disable(irq); 430 break; 431 } 432 } 433 434 /* 435 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's 436 * via6522.c :-), disable/pending masks added. 437 */ 438 439 void via1_irq(struct irq_desc *desc) 440 { 441 int irq_num; 442 unsigned char irq_bit, events; 443 444 events = via1[vIFR] & via1[vIER] & 0x7F; 445 if (!events) 446 return; 447 448 irq_num = VIA1_SOURCE_BASE; 449 irq_bit = 1; 450 do { 451 if (events & irq_bit) { 452 via1[vIFR] = irq_bit; 453 generic_handle_irq(irq_num); 454 } 455 ++irq_num; 456 irq_bit <<= 1; 457 } while (events >= irq_bit); 458 } 459 460 static void via2_irq(struct irq_desc *desc) 461 { 462 int irq_num; 463 unsigned char irq_bit, events; 464 465 events = via2[gIFR] & via2[gIER] & 0x7F; 466 if (!events) 467 return; 468 469 irq_num = VIA2_SOURCE_BASE; 470 irq_bit = 1; 471 do { 472 if (events & irq_bit) { 473 via2[gIFR] = irq_bit | rbv_clear; 474 generic_handle_irq(irq_num); 475 } 476 ++irq_num; 477 irq_bit <<= 1; 478 } while (events >= irq_bit); 479 } 480 481 /* 482 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the 483 * VIA2 dispatcher as a fast interrupt handler. 484 */ 485 486 static void via_nubus_irq(struct irq_desc *desc) 487 { 488 int slot_irq; 489 unsigned char slot_bit, events; 490 491 events = ~via2[gBufA] & 0x7F; 492 if (rbv_present) 493 events &= via2[rSIER]; 494 else 495 events &= ~via2[vDirA]; 496 if (!events) 497 return; 498 499 do { 500 slot_irq = IRQ_NUBUS_F; 501 slot_bit = 0x40; 502 do { 503 if (events & slot_bit) { 504 events &= ~slot_bit; 505 generic_handle_irq(slot_irq); 506 } 507 --slot_irq; 508 slot_bit >>= 1; 509 } while (events); 510 511 /* clear the CA1 interrupt and make certain there's no more. */ 512 via2[gIFR] = 0x02 | rbv_clear; 513 events = ~via2[gBufA] & 0x7F; 514 if (rbv_present) 515 events &= via2[rSIER]; 516 else 517 events &= ~via2[vDirA]; 518 } while (events); 519 } 520 521 /* 522 * Register the interrupt dispatchers for VIA or RBV machines only. 523 */ 524 525 void __init via_register_interrupts(void) 526 { 527 if (via_alt_mapping) { 528 /* software interrupt */ 529 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 530 /* via1 interrupt */ 531 irq_set_chained_handler(IRQ_AUTO_6, via1_irq); 532 } else { 533 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 534 } 535 irq_set_chained_handler(IRQ_AUTO_2, via2_irq); 536 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq); 537 } 538 539 void via_irq_enable(int irq) { 540 int irq_src = IRQ_SRC(irq); 541 int irq_idx = IRQ_IDX(irq); 542 543 if (irq_src == 1) { 544 via1[vIER] = IER_SET_BIT(irq_idx); 545 } else if (irq_src == 2) { 546 if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0) 547 via2[gIER] = IER_SET_BIT(irq_idx); 548 } else if (irq_src == 7) { 549 switch (macintosh_config->via_type) { 550 case MAC_VIA_II: 551 case MAC_VIA_QUADRA: 552 nubus_disabled &= ~(1 << irq_idx); 553 /* Enable the CA1 interrupt when no slot is disabled. */ 554 if (!nubus_disabled) 555 via2[gIER] = IER_SET_BIT(1); 556 break; 557 case MAC_VIA_IICI: 558 /* On RBV, enable the slot interrupt. 559 * SIER works like IER. 560 */ 561 via2[rSIER] = IER_SET_BIT(irq_idx); 562 break; 563 } 564 } 565 } 566 567 void via_irq_disable(int irq) { 568 int irq_src = IRQ_SRC(irq); 569 int irq_idx = IRQ_IDX(irq); 570 571 if (irq_src == 1) { 572 via1[vIER] = IER_CLR_BIT(irq_idx); 573 } else if (irq_src == 2) { 574 via2[gIER] = IER_CLR_BIT(irq_idx); 575 } else if (irq_src == 7) { 576 switch (macintosh_config->via_type) { 577 case MAC_VIA_II: 578 case MAC_VIA_QUADRA: 579 nubus_disabled |= 1 << irq_idx; 580 if (nubus_disabled) 581 via2[gIER] = IER_CLR_BIT(1); 582 break; 583 case MAC_VIA_IICI: 584 via2[rSIER] = IER_CLR_BIT(irq_idx); 585 break; 586 } 587 } 588 } 589 590 void via1_set_head(int head) 591 { 592 if (head == 0) 593 via1[vBufA] &= ~VIA1A_vHeadSel; 594 else 595 via1[vBufA] |= VIA1A_vHeadSel; 596 } 597 EXPORT_SYMBOL(via1_set_head); 598 599 int via2_scsi_drq_pending(void) 600 { 601 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ)); 602 } 603 EXPORT_SYMBOL(via2_scsi_drq_pending); 604