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/clocksource.h> 27 #include <linux/types.h> 28 #include <linux/kernel.h> 29 #include <linux/mm.h> 30 #include <linux/delay.h> 31 #include <linux/init.h> 32 #include <linux/module.h> 33 #include <linux/irq.h> 34 35 #include <asm/macintosh.h> 36 #include <asm/macints.h> 37 #include <asm/mac_via.h> 38 #include <asm/mac_psc.h> 39 #include <asm/mac_oss.h> 40 41 volatile __u8 *via1, *via2; 42 int rbv_present; 43 int via_alt_mapping; 44 EXPORT_SYMBOL(via_alt_mapping); 45 static __u8 rbv_clear; 46 47 /* 48 * Globals for accessing the VIA chip registers without having to 49 * check if we're hitting a real VIA or an RBV. Normally you could 50 * just hit the combined register (ie, vIER|rIER) but that seems to 51 * break on AV Macs...probably because they actually decode more than 52 * eight address bits. Why can't Apple engineers at least be 53 * _consistently_ lazy? - 1999-05-21 (jmt) 54 */ 55 56 static int gIER,gIFR,gBufA,gBufB; 57 58 /* 59 * On Macs with a genuine VIA chip there is no way to mask an individual slot 60 * interrupt. This limitation also seems to apply to VIA clone logic cores in 61 * Quadra-like ASICs. (RBV and OSS machines don't have this limitation.) 62 * 63 * We used to fake it by configuring the relevant VIA pin as an output 64 * (to mask the interrupt) or input (to unmask). That scheme did not work on 65 * (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector 66 * circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE, 67 * p. 10-11 etc) but VIA outputs are not (see datasheet). 68 * 69 * Driving these outputs high must cause the VIA to source current and the 70 * card to sink current when it asserts /NMRQ. Current will flow but the pin 71 * voltage is uncertain and so the /NMRQ condition may still cause a transition 72 * at the VIA2 CA1 input (which explains the lost interrupts). A side effect 73 * is that a disabled slot IRQ can never be tested as pending or not. 74 * 75 * Driving these outputs low doesn't work either. All the slot /NMRQ lines are 76 * (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see 77 * The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a 78 * disabled /NMRQ line low, the falling edge immediately triggers a CA1 79 * interrupt and all slot interrupts after that will generate no transition 80 * and therefore no interrupt, even after being re-enabled. 81 * 82 * So we make the VIA port A I/O lines inputs and use nubus_disabled to keep 83 * track of their states. When any slot IRQ becomes disabled we mask the CA1 84 * umbrella interrupt. Only when all slot IRQs become enabled do we unmask 85 * the CA1 interrupt. It must remain enabled even when cards have no interrupt 86 * handler registered. Drivers must therefore disable a slot interrupt at the 87 * device before they call free_irq (like shared and autovector interrupts). 88 * 89 * There is also a related problem when MacOS is used to boot Linux. A network 90 * card brought up by a MacOS driver may raise an interrupt while Linux boots. 91 * This can be fatal since it can't be handled until the right driver loads 92 * (if such a driver exists at all). Apparently related to this hardware 93 * limitation, "Designing Cards and Drivers", p. 9-8, says that a slot 94 * interrupt with no driver would crash MacOS (the book was written before 95 * the appearance of Macs with RBV or OSS). 96 */ 97 98 static u8 nubus_disabled; 99 100 void via_debug_dump(void); 101 static void via_nubus_init(void); 102 103 /* 104 * Initialize the VIAs 105 * 106 * First we figure out where they actually _are_ as well as what type of 107 * VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.) 108 * Then we pretty much clear them out and disable all IRQ sources. 109 */ 110 111 void __init via_init(void) 112 { 113 via1 = (void *)VIA1_BASE; 114 pr_debug("VIA1 detected at %p\n", via1); 115 116 if (oss_present) { 117 via2 = NULL; 118 rbv_present = 0; 119 } else { 120 switch (macintosh_config->via_type) { 121 122 /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */ 123 124 case MAC_VIA_IICI: 125 via2 = (void *)RBV_BASE; 126 pr_debug("VIA2 (RBV) detected at %p\n", via2); 127 rbv_present = 1; 128 if (macintosh_config->ident == MAC_MODEL_LCIII) { 129 rbv_clear = 0x00; 130 } else { 131 /* on most RBVs (& unlike the VIAs), you */ 132 /* need to set bit 7 when you write to IFR */ 133 /* in order for your clear to occur. */ 134 rbv_clear = 0x80; 135 } 136 gIER = rIER; 137 gIFR = rIFR; 138 gBufA = rSIFR; 139 gBufB = rBufB; 140 break; 141 142 /* Quadra and early MacIIs agree on the VIA locations */ 143 144 case MAC_VIA_QUADRA: 145 case MAC_VIA_II: 146 via2 = (void *) VIA2_BASE; 147 pr_debug("VIA2 detected at %p\n", via2); 148 rbv_present = 0; 149 rbv_clear = 0x00; 150 gIER = vIER; 151 gIFR = vIFR; 152 gBufA = vBufA; 153 gBufB = vBufB; 154 break; 155 156 default: 157 panic("UNKNOWN VIA TYPE"); 158 } 159 } 160 161 #ifdef DEBUG_VIA 162 via_debug_dump(); 163 #endif 164 165 /* 166 * Shut down all IRQ sources, reset the timers, and 167 * kill the timer latch on VIA1. 168 */ 169 170 via1[vIER] = 0x7F; 171 via1[vIFR] = 0x7F; 172 via1[vT1LL] = 0; 173 via1[vT1LH] = 0; 174 via1[vT1CL] = 0; 175 via1[vT1CH] = 0; 176 via1[vT2CL] = 0; 177 via1[vT2CH] = 0; 178 via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 179 via1[vACR] &= ~0x03; /* disable port A & B latches */ 180 181 /* 182 * SE/30: disable video IRQ 183 */ 184 185 if (macintosh_config->ident == MAC_MODEL_SE30) { 186 via1[vDirB] |= 0x40; 187 via1[vBufB] |= 0x40; 188 } 189 190 switch (macintosh_config->adb_type) { 191 case MAC_ADB_IOP: 192 case MAC_ADB_II: 193 case MAC_ADB_PB1: 194 /* 195 * Set the RTC bits to a known state: all lines to outputs and 196 * RTC disabled (yes that's 0 to enable and 1 to disable). 197 */ 198 via1[vDirB] |= VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData; 199 via1[vBufB] |= VIA1B_vRTCEnb | VIA1B_vRTCClk; 200 break; 201 } 202 203 /* Everything below this point is VIA2/RBV only... */ 204 205 if (oss_present) 206 return; 207 208 if ((macintosh_config->via_type == MAC_VIA_QUADRA) && 209 (macintosh_config->adb_type != MAC_ADB_PB1) && 210 (macintosh_config->adb_type != MAC_ADB_PB2) && 211 (macintosh_config->ident != MAC_MODEL_C660) && 212 (macintosh_config->ident != MAC_MODEL_Q840)) { 213 via_alt_mapping = 1; 214 via1[vDirB] |= 0x40; 215 via1[vBufB] &= ~0x40; 216 } else { 217 via_alt_mapping = 0; 218 } 219 220 /* 221 * Now initialize VIA2. For RBV we just kill all interrupts; 222 * for a regular VIA we also reset the timers and stuff. 223 */ 224 225 via2[gIER] = 0x7F; 226 via2[gIFR] = 0x7F | rbv_clear; 227 if (!rbv_present) { 228 via2[vT1LL] = 0; 229 via2[vT1LH] = 0; 230 via2[vT1CL] = 0; 231 via2[vT1CH] = 0; 232 via2[vT2CL] = 0; 233 via2[vT2CH] = 0; 234 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 235 via2[vACR] &= ~0x03; /* disable port A & B latches */ 236 } 237 238 via_nubus_init(); 239 240 /* Everything below this point is VIA2 only... */ 241 242 if (rbv_present) 243 return; 244 245 /* 246 * Set vPCR for control line interrupts. 247 * 248 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger. 249 * 250 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt. 251 * Testing reveals that PowerBooks do too. However, the SE/30 252 * schematic diagram shows an active high NCR5380 IRQ line. 253 */ 254 255 pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]); 256 if (macintosh_config->via_type == MAC_VIA_II) { 257 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */ 258 via2[vPCR] = 0x66; 259 } else { 260 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */ 261 via2[vPCR] = 0x22; 262 } 263 } 264 265 /* 266 * Debugging dump, used in various places to see what's going on. 267 */ 268 269 void via_debug_dump(void) 270 { 271 printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 272 (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]); 273 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 274 (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]); 275 if (!via2) 276 return; 277 if (rbv_present) { 278 printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n", 279 (uint) via2[rIFR], (uint) via2[rIER]); 280 printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n", 281 (uint) via2[rSIFR], (uint) via2[rSIER]); 282 } else { 283 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 284 (uint) via2[vDirA], (uint) via2[vDirB], 285 (uint) via2[vACR]); 286 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 287 (uint) via2[vPCR], 288 (uint) via2[vIFR], (uint) via2[vIER]); 289 } 290 } 291 292 /* 293 * Flush the L2 cache on Macs that have it by flipping 294 * the system into 24-bit mode for an instant. 295 */ 296 297 void via_l2_flush(int writeback) 298 { 299 unsigned long flags; 300 301 local_irq_save(flags); 302 via2[gBufB] &= ~VIA2B_vMode32; 303 via2[gBufB] |= VIA2B_vMode32; 304 local_irq_restore(flags); 305 } 306 307 /* 308 * Return the status of the L2 cache on a IIci 309 */ 310 311 int via_get_cache_disable(void) 312 { 313 /* Safeguard against being called accidentally */ 314 if (!via2) { 315 printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n"); 316 return 1; 317 } 318 319 return (int) via2[gBufB] & VIA2B_vCDis; 320 } 321 322 /* 323 * Initialize VIA2 for Nubus access 324 */ 325 326 static void __init via_nubus_init(void) 327 { 328 /* unlock nubus transactions */ 329 330 if ((macintosh_config->adb_type != MAC_ADB_PB1) && 331 (macintosh_config->adb_type != MAC_ADB_PB2)) { 332 /* set the line to be an output on non-RBV machines */ 333 if (!rbv_present) 334 via2[vDirB] |= 0x02; 335 336 /* this seems to be an ADB bit on PMU machines */ 337 /* according to MkLinux. -- jmt */ 338 via2[gBufB] |= 0x02; 339 } 340 341 /* 342 * Disable the slot interrupts. On some hardware that's not possible. 343 * On some hardware it's unclear what all of these I/O lines do. 344 */ 345 346 switch (macintosh_config->via_type) { 347 case MAC_VIA_II: 348 case MAC_VIA_QUADRA: 349 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]); 350 break; 351 case MAC_VIA_IICI: 352 /* RBV. Disable all the slot interrupts. SIER works like IER. */ 353 via2[rSIER] = 0x7F; 354 break; 355 } 356 } 357 358 void via_nubus_irq_startup(int irq) 359 { 360 int irq_idx = IRQ_IDX(irq); 361 362 switch (macintosh_config->via_type) { 363 case MAC_VIA_II: 364 case MAC_VIA_QUADRA: 365 /* Make the port A line an input. Probably redundant. */ 366 if (macintosh_config->via_type == MAC_VIA_II) { 367 /* The top two bits are RAM size outputs. */ 368 via2[vDirA] &= 0xC0 | ~(1 << irq_idx); 369 } else { 370 /* Allow NuBus slots 9 through F. */ 371 via2[vDirA] &= 0x80 | ~(1 << irq_idx); 372 } 373 fallthrough; 374 case MAC_VIA_IICI: 375 via_irq_enable(irq); 376 break; 377 } 378 } 379 380 void via_nubus_irq_shutdown(int irq) 381 { 382 switch (macintosh_config->via_type) { 383 case MAC_VIA_II: 384 case MAC_VIA_QUADRA: 385 /* Ensure that the umbrella CA1 interrupt remains enabled. */ 386 via_irq_enable(irq); 387 break; 388 case MAC_VIA_IICI: 389 via_irq_disable(irq); 390 break; 391 } 392 } 393 394 /* 395 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's 396 * via6522.c :-), disable/pending masks added. 397 */ 398 399 #define VIA_TIMER_1_INT BIT(6) 400 401 void via1_irq(struct irq_desc *desc) 402 { 403 int irq_num; 404 unsigned char irq_bit, events; 405 406 events = via1[vIFR] & via1[vIER] & 0x7F; 407 if (!events) 408 return; 409 410 irq_num = IRQ_MAC_TIMER_1; 411 irq_bit = VIA_TIMER_1_INT; 412 if (events & irq_bit) { 413 unsigned long flags; 414 415 local_irq_save(flags); 416 via1[vIFR] = irq_bit; 417 generic_handle_irq(irq_num); 418 local_irq_restore(flags); 419 420 events &= ~irq_bit; 421 if (!events) 422 return; 423 } 424 425 irq_num = VIA1_SOURCE_BASE; 426 irq_bit = 1; 427 do { 428 if (events & irq_bit) { 429 via1[vIFR] = irq_bit; 430 generic_handle_irq(irq_num); 431 } 432 ++irq_num; 433 irq_bit <<= 1; 434 } while (events >= irq_bit); 435 } 436 437 static void via2_irq(struct irq_desc *desc) 438 { 439 int irq_num; 440 unsigned char irq_bit, events; 441 442 events = via2[gIFR] & via2[gIER] & 0x7F; 443 if (!events) 444 return; 445 446 irq_num = VIA2_SOURCE_BASE; 447 irq_bit = 1; 448 do { 449 if (events & irq_bit) { 450 via2[gIFR] = irq_bit | rbv_clear; 451 generic_handle_irq(irq_num); 452 } 453 ++irq_num; 454 irq_bit <<= 1; 455 } while (events >= irq_bit); 456 } 457 458 /* 459 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the 460 * VIA2 dispatcher as a fast interrupt handler. 461 */ 462 463 static void via_nubus_irq(struct irq_desc *desc) 464 { 465 int slot_irq; 466 unsigned char slot_bit, events; 467 468 events = ~via2[gBufA] & 0x7F; 469 if (rbv_present) 470 events &= via2[rSIER]; 471 else 472 events &= ~via2[vDirA]; 473 if (!events) 474 return; 475 476 do { 477 slot_irq = IRQ_NUBUS_F; 478 slot_bit = 0x40; 479 do { 480 if (events & slot_bit) { 481 events &= ~slot_bit; 482 generic_handle_irq(slot_irq); 483 } 484 --slot_irq; 485 slot_bit >>= 1; 486 } while (events); 487 488 /* clear the CA1 interrupt and make certain there's no more. */ 489 via2[gIFR] = 0x02 | rbv_clear; 490 events = ~via2[gBufA] & 0x7F; 491 if (rbv_present) 492 events &= via2[rSIER]; 493 else 494 events &= ~via2[vDirA]; 495 } while (events); 496 } 497 498 /* 499 * Register the interrupt dispatchers for VIA or RBV machines only. 500 */ 501 502 void __init via_register_interrupts(void) 503 { 504 if (via_alt_mapping) { 505 /* software interrupt */ 506 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 507 /* via1 interrupt */ 508 irq_set_chained_handler(IRQ_AUTO_6, via1_irq); 509 } else { 510 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 511 } 512 irq_set_chained_handler(IRQ_AUTO_2, via2_irq); 513 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq); 514 } 515 516 void via_irq_enable(int irq) { 517 int irq_src = IRQ_SRC(irq); 518 int irq_idx = IRQ_IDX(irq); 519 520 if (irq_src == 1) { 521 via1[vIER] = IER_SET_BIT(irq_idx); 522 } else if (irq_src == 2) { 523 if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0) 524 via2[gIER] = IER_SET_BIT(irq_idx); 525 } else if (irq_src == 7) { 526 switch (macintosh_config->via_type) { 527 case MAC_VIA_II: 528 case MAC_VIA_QUADRA: 529 nubus_disabled &= ~(1 << irq_idx); 530 /* Enable the CA1 interrupt when no slot is disabled. */ 531 if (!nubus_disabled) 532 via2[gIER] = IER_SET_BIT(1); 533 break; 534 case MAC_VIA_IICI: 535 /* On RBV, enable the slot interrupt. 536 * SIER works like IER. 537 */ 538 via2[rSIER] = IER_SET_BIT(irq_idx); 539 break; 540 } 541 } 542 } 543 544 void via_irq_disable(int irq) { 545 int irq_src = IRQ_SRC(irq); 546 int irq_idx = IRQ_IDX(irq); 547 548 if (irq_src == 1) { 549 via1[vIER] = IER_CLR_BIT(irq_idx); 550 } else if (irq_src == 2) { 551 via2[gIER] = IER_CLR_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 if (nubus_disabled) 558 via2[gIER] = IER_CLR_BIT(1); 559 break; 560 case MAC_VIA_IICI: 561 via2[rSIER] = IER_CLR_BIT(irq_idx); 562 break; 563 } 564 } 565 } 566 567 void via1_set_head(int head) 568 { 569 if (head == 0) 570 via1[vBufA] &= ~VIA1A_vHeadSel; 571 else 572 via1[vBufA] |= VIA1A_vHeadSel; 573 } 574 EXPORT_SYMBOL(via1_set_head); 575 576 int via2_scsi_drq_pending(void) 577 { 578 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ)); 579 } 580 EXPORT_SYMBOL(via2_scsi_drq_pending); 581 582 /* timer and clock source */ 583 584 #define VIA_CLOCK_FREQ 783360 /* VIA "phase 2" clock in Hz */ 585 #define VIA_TIMER_CYCLES (VIA_CLOCK_FREQ / HZ) /* clock cycles per jiffy */ 586 587 #define VIA_TC (VIA_TIMER_CYCLES - 2) /* including 0 and -1 */ 588 #define VIA_TC_LOW (VIA_TC & 0xFF) 589 #define VIA_TC_HIGH (VIA_TC >> 8) 590 591 static u64 mac_read_clk(struct clocksource *cs); 592 593 static struct clocksource mac_clk = { 594 .name = "via1", 595 .rating = 250, 596 .read = mac_read_clk, 597 .mask = CLOCKSOURCE_MASK(32), 598 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 599 }; 600 601 static u32 clk_total, clk_offset; 602 603 static irqreturn_t via_timer_handler(int irq, void *dev_id) 604 { 605 irq_handler_t timer_routine = dev_id; 606 607 clk_total += VIA_TIMER_CYCLES; 608 clk_offset = 0; 609 timer_routine(0, NULL); 610 611 return IRQ_HANDLED; 612 } 613 614 void __init via_init_clock(irq_handler_t timer_routine) 615 { 616 if (request_irq(IRQ_MAC_TIMER_1, via_timer_handler, IRQF_TIMER, "timer", 617 timer_routine)) { 618 pr_err("Couldn't register %s interrupt\n", "timer"); 619 return; 620 } 621 622 via1[vT1LL] = VIA_TC_LOW; 623 via1[vT1LH] = VIA_TC_HIGH; 624 via1[vT1CL] = VIA_TC_LOW; 625 via1[vT1CH] = VIA_TC_HIGH; 626 via1[vACR] |= 0x40; 627 628 clocksource_register_hz(&mac_clk, VIA_CLOCK_FREQ); 629 } 630 631 static u64 mac_read_clk(struct clocksource *cs) 632 { 633 unsigned long flags; 634 u8 count_high; 635 u16 count; 636 u32 ticks; 637 638 /* 639 * Timer counter wrap-around is detected with the timer interrupt flag 640 * but reading the counter low byte (vT1CL) would reset the flag. 641 * Also, accessing both counter registers is essentially a data race. 642 * These problems are avoided by ignoring the low byte. Clock accuracy 643 * is 256 times worse (error can reach 0.327 ms) but CPU overhead is 644 * reduced by avoiding slow VIA register accesses. 645 */ 646 647 local_irq_save(flags); 648 count_high = via1[vT1CH]; 649 if (count_high == 0xFF) 650 count_high = 0; 651 if (count_high > 0 && (via1[vIFR] & VIA_TIMER_1_INT)) 652 clk_offset = VIA_TIMER_CYCLES; 653 count = count_high << 8; 654 ticks = VIA_TIMER_CYCLES - count; 655 ticks += clk_offset + clk_total; 656 local_irq_restore(flags); 657 658 return ticks; 659 } 660