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); 110 111 /* 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 * Note: the OSS is actually "detected" here and not in oss_init(). It just 119 * seems more logical to do it here since via_init() needs to know 120 * these things anyways. 121 */ 122 123 void __init via_init(void) 124 { 125 switch(macintosh_config->via_type) { 126 127 /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */ 128 129 case MAC_VIA_IICI: 130 via1 = (void *) VIA1_BASE; 131 if (macintosh_config->ident == MAC_MODEL_IIFX) { 132 via2 = NULL; 133 rbv_present = 0; 134 oss_present = 1; 135 } else { 136 via2 = (void *) RBV_BASE; 137 rbv_present = 1; 138 oss_present = 0; 139 } 140 if (macintosh_config->ident == MAC_MODEL_LCIII) { 141 rbv_clear = 0x00; 142 } else { 143 /* on most RBVs (& unlike the VIAs), you */ 144 /* need to set bit 7 when you write to IFR */ 145 /* in order for your clear to occur. */ 146 rbv_clear = 0x80; 147 } 148 gIER = rIER; 149 gIFR = rIFR; 150 gBufA = rSIFR; 151 gBufB = rBufB; 152 break; 153 154 /* Quadra and early MacIIs agree on the VIA locations */ 155 156 case MAC_VIA_QUADRA: 157 case MAC_VIA_II: 158 via1 = (void *) VIA1_BASE; 159 via2 = (void *) VIA2_BASE; 160 rbv_present = 0; 161 oss_present = 0; 162 rbv_clear = 0x00; 163 gIER = vIER; 164 gIFR = vIFR; 165 gBufA = vBufA; 166 gBufB = vBufB; 167 break; 168 default: 169 panic("UNKNOWN VIA TYPE"); 170 } 171 172 printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1); 173 174 printk(KERN_INFO "VIA2 at %p is ", via2); 175 if (rbv_present) { 176 printk("an RBV\n"); 177 } else if (oss_present) { 178 printk("an OSS\n"); 179 } else { 180 printk("a 6522 or clone\n"); 181 } 182 183 #ifdef DEBUG_VIA 184 via_debug_dump(); 185 #endif 186 187 /* 188 * Shut down all IRQ sources, reset the timers, and 189 * kill the timer latch on VIA1. 190 */ 191 192 via1[vIER] = 0x7F; 193 via1[vIFR] = 0x7F; 194 via1[vT1LL] = 0; 195 via1[vT1LH] = 0; 196 via1[vT1CL] = 0; 197 via1[vT1CH] = 0; 198 via1[vT2CL] = 0; 199 via1[vT2CH] = 0; 200 via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 201 via1[vACR] &= ~0x03; /* disable port A & B latches */ 202 203 /* 204 * SE/30: disable video IRQ 205 * XXX: testing for SE/30 VBL 206 */ 207 208 if (macintosh_config->ident == MAC_MODEL_SE30) { 209 via1[vDirB] |= 0x40; 210 via1[vBufB] |= 0x40; 211 } 212 213 /* 214 * Set the RTC bits to a known state: all lines to outputs and 215 * RTC disabled (yes that's 0 to enable and 1 to disable). 216 */ 217 218 via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData); 219 via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk); 220 221 /* Everything below this point is VIA2/RBV only... */ 222 223 if (oss_present) 224 return; 225 226 if ((macintosh_config->via_type == MAC_VIA_QUADRA) && 227 (macintosh_config->adb_type != MAC_ADB_PB1) && 228 (macintosh_config->adb_type != MAC_ADB_PB2) && 229 (macintosh_config->ident != MAC_MODEL_C660) && 230 (macintosh_config->ident != MAC_MODEL_Q840)) { 231 via_alt_mapping = 1; 232 via1[vDirB] |= 0x40; 233 via1[vBufB] &= ~0x40; 234 } else { 235 via_alt_mapping = 0; 236 } 237 238 /* 239 * Now initialize VIA2. For RBV we just kill all interrupts; 240 * for a regular VIA we also reset the timers and stuff. 241 */ 242 243 via2[gIER] = 0x7F; 244 via2[gIFR] = 0x7F | rbv_clear; 245 if (!rbv_present) { 246 via2[vT1LL] = 0; 247 via2[vT1LH] = 0; 248 via2[vT1CL] = 0; 249 via2[vT1CH] = 0; 250 via2[vT2CL] = 0; 251 via2[vT2CH] = 0; 252 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 253 via2[vACR] &= ~0x03; /* disable port A & B latches */ 254 } 255 256 /* Everything below this point is VIA2 only... */ 257 258 if (rbv_present) 259 return; 260 261 /* 262 * Set vPCR for control line interrupts. 263 * 264 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger. 265 * 266 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt. 267 * Testing reveals that PowerBooks do too. However, the SE/30 268 * schematic diagram shows an active high NCR5380 IRQ line. 269 */ 270 271 pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]); 272 if (macintosh_config->via_type == MAC_VIA_II) { 273 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */ 274 via2[vPCR] = 0x66; 275 } else { 276 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */ 277 via2[vPCR] = 0x22; 278 } 279 } 280 281 /* 282 * Start the 100 Hz clock 283 */ 284 285 void __init via_init_clock(irq_handler_t func) 286 { 287 via1[vACR] |= 0x40; 288 via1[vT1LL] = MAC_CLOCK_LOW; 289 via1[vT1LH] = MAC_CLOCK_HIGH; 290 via1[vT1CL] = MAC_CLOCK_LOW; 291 via1[vT1CH] = MAC_CLOCK_HIGH; 292 293 if (request_irq(IRQ_MAC_TIMER_1, func, 0, "timer", func)) 294 pr_err("Couldn't register %s interrupt\n", "timer"); 295 } 296 297 /* 298 * Debugging dump, used in various places to see what's going on. 299 */ 300 301 void via_debug_dump(void) 302 { 303 printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 304 (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]); 305 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 306 (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]); 307 if (oss_present) { 308 printk(KERN_DEBUG "VIA2: <OSS>\n"); 309 } else if (rbv_present) { 310 printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n", 311 (uint) via2[rIFR], (uint) via2[rIER]); 312 printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n", 313 (uint) via2[rSIFR], (uint) via2[rSIER]); 314 } else { 315 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 316 (uint) via2[vDirA], (uint) via2[vDirB], 317 (uint) via2[vACR]); 318 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 319 (uint) via2[vPCR], 320 (uint) via2[vIFR], (uint) via2[vIER]); 321 } 322 } 323 324 /* 325 * This is always executed with interrupts disabled. 326 * 327 * TBI: get time offset between scheduling timer ticks 328 */ 329 330 u32 mac_gettimeoffset(void) 331 { 332 unsigned long ticks, offset = 0; 333 334 /* read VIA1 timer 2 current value */ 335 ticks = via1[vT1CL] | (via1[vT1CH] << 8); 336 /* The probability of underflow is less than 2% */ 337 if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50) 338 /* Check for pending timer interrupt in VIA1 IFR */ 339 if (via1[vIFR] & 0x40) offset = TICK_SIZE; 340 341 ticks = MAC_CLOCK_TICK - ticks; 342 ticks = ticks * 10000L / MAC_CLOCK_TICK; 343 344 return (ticks + offset) * 1000; 345 } 346 347 /* 348 * Flush the L2 cache on Macs that have it by flipping 349 * the system into 24-bit mode for an instant. 350 */ 351 352 void via_flush_cache(void) 353 { 354 via2[gBufB] &= ~VIA2B_vMode32; 355 via2[gBufB] |= VIA2B_vMode32; 356 } 357 358 /* 359 * Return the status of the L2 cache on a IIci 360 */ 361 362 int via_get_cache_disable(void) 363 { 364 /* Safeguard against being called accidentally */ 365 if (!via2) { 366 printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n"); 367 return 1; 368 } 369 370 return (int) via2[gBufB] & VIA2B_vCDis; 371 } 372 373 /* 374 * Initialize VIA2 for Nubus access 375 */ 376 377 void __init via_nubus_init(void) 378 { 379 /* unlock nubus transactions */ 380 381 if ((macintosh_config->adb_type != MAC_ADB_PB1) && 382 (macintosh_config->adb_type != MAC_ADB_PB2)) { 383 /* set the line to be an output on non-RBV machines */ 384 if (!rbv_present) 385 via2[vDirB] |= 0x02; 386 387 /* this seems to be an ADB bit on PMU machines */ 388 /* according to MkLinux. -- jmt */ 389 via2[gBufB] |= 0x02; 390 } 391 392 /* 393 * Disable the slot interrupts. On some hardware that's not possible. 394 * On some hardware it's unclear what all of these I/O lines do. 395 */ 396 397 switch (macintosh_config->via_type) { 398 case MAC_VIA_II: 399 case MAC_VIA_QUADRA: 400 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]); 401 break; 402 case MAC_VIA_IICI: 403 /* RBV. Disable all the slot interrupts. SIER works like IER. */ 404 via2[rSIER] = 0x7F; 405 break; 406 } 407 } 408 409 void via_nubus_irq_startup(int irq) 410 { 411 int irq_idx = IRQ_IDX(irq); 412 413 switch (macintosh_config->via_type) { 414 case MAC_VIA_II: 415 case MAC_VIA_QUADRA: 416 /* Make the port A line an input. Probably redundant. */ 417 if (macintosh_config->via_type == MAC_VIA_II) { 418 /* The top two bits are RAM size outputs. */ 419 via2[vDirA] &= 0xC0 | ~(1 << irq_idx); 420 } else { 421 /* Allow NuBus slots 9 through F. */ 422 via2[vDirA] &= 0x80 | ~(1 << irq_idx); 423 } 424 /* fall through */ 425 case MAC_VIA_IICI: 426 via_irq_enable(irq); 427 break; 428 } 429 } 430 431 void via_nubus_irq_shutdown(int irq) 432 { 433 switch (macintosh_config->via_type) { 434 case MAC_VIA_II: 435 case MAC_VIA_QUADRA: 436 /* Ensure that the umbrella CA1 interrupt remains enabled. */ 437 via_irq_enable(irq); 438 break; 439 case MAC_VIA_IICI: 440 via_irq_disable(irq); 441 break; 442 } 443 } 444 445 /* 446 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's 447 * via6522.c :-), disable/pending masks added. 448 */ 449 450 void via1_irq(struct irq_desc *desc) 451 { 452 int irq_num; 453 unsigned char irq_bit, events; 454 455 events = via1[vIFR] & via1[vIER] & 0x7F; 456 if (!events) 457 return; 458 459 irq_num = VIA1_SOURCE_BASE; 460 irq_bit = 1; 461 do { 462 if (events & irq_bit) { 463 via1[vIFR] = irq_bit; 464 generic_handle_irq(irq_num); 465 } 466 ++irq_num; 467 irq_bit <<= 1; 468 } while (events >= irq_bit); 469 } 470 471 static void via2_irq(struct irq_desc *desc) 472 { 473 int irq_num; 474 unsigned char irq_bit, events; 475 476 events = via2[gIFR] & via2[gIER] & 0x7F; 477 if (!events) 478 return; 479 480 irq_num = VIA2_SOURCE_BASE; 481 irq_bit = 1; 482 do { 483 if (events & irq_bit) { 484 via2[gIFR] = irq_bit | rbv_clear; 485 generic_handle_irq(irq_num); 486 } 487 ++irq_num; 488 irq_bit <<= 1; 489 } while (events >= irq_bit); 490 } 491 492 /* 493 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the 494 * VIA2 dispatcher as a fast interrupt handler. 495 */ 496 497 static void via_nubus_irq(struct irq_desc *desc) 498 { 499 int slot_irq; 500 unsigned char slot_bit, events; 501 502 events = ~via2[gBufA] & 0x7F; 503 if (rbv_present) 504 events &= via2[rSIER]; 505 else 506 events &= ~via2[vDirA]; 507 if (!events) 508 return; 509 510 do { 511 slot_irq = IRQ_NUBUS_F; 512 slot_bit = 0x40; 513 do { 514 if (events & slot_bit) { 515 events &= ~slot_bit; 516 generic_handle_irq(slot_irq); 517 } 518 --slot_irq; 519 slot_bit >>= 1; 520 } while (events); 521 522 /* clear the CA1 interrupt and make certain there's no more. */ 523 via2[gIFR] = 0x02 | rbv_clear; 524 events = ~via2[gBufA] & 0x7F; 525 if (rbv_present) 526 events &= via2[rSIER]; 527 else 528 events &= ~via2[vDirA]; 529 } while (events); 530 } 531 532 /* 533 * Register the interrupt dispatchers for VIA or RBV machines only. 534 */ 535 536 void __init via_register_interrupts(void) 537 { 538 if (via_alt_mapping) { 539 /* software interrupt */ 540 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 541 /* via1 interrupt */ 542 irq_set_chained_handler(IRQ_AUTO_6, via1_irq); 543 } else { 544 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 545 } 546 irq_set_chained_handler(IRQ_AUTO_2, via2_irq); 547 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq); 548 } 549 550 void via_irq_enable(int irq) { 551 int irq_src = IRQ_SRC(irq); 552 int irq_idx = IRQ_IDX(irq); 553 554 if (irq_src == 1) { 555 via1[vIER] = IER_SET_BIT(irq_idx); 556 } else if (irq_src == 2) { 557 if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0) 558 via2[gIER] = IER_SET_BIT(irq_idx); 559 } else if (irq_src == 7) { 560 switch (macintosh_config->via_type) { 561 case MAC_VIA_II: 562 case MAC_VIA_QUADRA: 563 nubus_disabled &= ~(1 << irq_idx); 564 /* Enable the CA1 interrupt when no slot is disabled. */ 565 if (!nubus_disabled) 566 via2[gIER] = IER_SET_BIT(1); 567 break; 568 case MAC_VIA_IICI: 569 /* On RBV, enable the slot interrupt. 570 * SIER works like IER. 571 */ 572 via2[rSIER] = IER_SET_BIT(irq_idx); 573 break; 574 } 575 } 576 } 577 578 void via_irq_disable(int irq) { 579 int irq_src = IRQ_SRC(irq); 580 int irq_idx = IRQ_IDX(irq); 581 582 if (irq_src == 1) { 583 via1[vIER] = IER_CLR_BIT(irq_idx); 584 } else if (irq_src == 2) { 585 via2[gIER] = IER_CLR_BIT(irq_idx); 586 } else if (irq_src == 7) { 587 switch (macintosh_config->via_type) { 588 case MAC_VIA_II: 589 case MAC_VIA_QUADRA: 590 nubus_disabled |= 1 << irq_idx; 591 if (nubus_disabled) 592 via2[gIER] = IER_CLR_BIT(1); 593 break; 594 case MAC_VIA_IICI: 595 via2[rSIER] = IER_CLR_BIT(irq_idx); 596 break; 597 } 598 } 599 } 600 601 void via1_set_head(int head) 602 { 603 if (head == 0) 604 via1[vBufA] &= ~VIA1A_vHeadSel; 605 else 606 via1[vBufA] |= VIA1A_vHeadSel; 607 } 608 EXPORT_SYMBOL(via1_set_head); 609 610 int via2_scsi_drq_pending(void) 611 { 612 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ)); 613 } 614 EXPORT_SYMBOL(via2_scsi_drq_pending); 615