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 #include "mac.h" 42 43 volatile __u8 *via1, *via2; 44 int rbv_present; 45 int via_alt_mapping; 46 EXPORT_SYMBOL(via_alt_mapping); 47 static __u8 rbv_clear; 48 49 /* 50 * Globals for accessing the VIA chip registers without having to 51 * check if we're hitting a real VIA or an RBV. Normally you could 52 * just hit the combined register (ie, vIER|rIER) but that seems to 53 * break on AV Macs...probably because they actually decode more than 54 * eight address bits. Why can't Apple engineers at least be 55 * _consistently_ lazy? - 1999-05-21 (jmt) 56 */ 57 58 static int gIER,gIFR,gBufA,gBufB; 59 60 /* 61 * On Macs with a genuine VIA chip there is no way to mask an individual slot 62 * interrupt. This limitation also seems to apply to VIA clone logic cores in 63 * Quadra-like ASICs. (RBV and OSS machines don't have this limitation.) 64 * 65 * We used to fake it by configuring the relevant VIA pin as an output 66 * (to mask the interrupt) or input (to unmask). That scheme did not work on 67 * (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector 68 * circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE, 69 * p. 10-11 etc) but VIA outputs are not (see datasheet). 70 * 71 * Driving these outputs high must cause the VIA to source current and the 72 * card to sink current when it asserts /NMRQ. Current will flow but the pin 73 * voltage is uncertain and so the /NMRQ condition may still cause a transition 74 * at the VIA2 CA1 input (which explains the lost interrupts). A side effect 75 * is that a disabled slot IRQ can never be tested as pending or not. 76 * 77 * Driving these outputs low doesn't work either. All the slot /NMRQ lines are 78 * (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see 79 * The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a 80 * disabled /NMRQ line low, the falling edge immediately triggers a CA1 81 * interrupt and all slot interrupts after that will generate no transition 82 * and therefore no interrupt, even after being re-enabled. 83 * 84 * So we make the VIA port A I/O lines inputs and use nubus_disabled to keep 85 * track of their states. When any slot IRQ becomes disabled we mask the CA1 86 * umbrella interrupt. Only when all slot IRQs become enabled do we unmask 87 * the CA1 interrupt. It must remain enabled even when cards have no interrupt 88 * handler registered. Drivers must therefore disable a slot interrupt at the 89 * device before they call free_irq (like shared and autovector interrupts). 90 * 91 * There is also a related problem when MacOS is used to boot Linux. A network 92 * card brought up by a MacOS driver may raise an interrupt while Linux boots. 93 * This can be fatal since it can't be handled until the right driver loads 94 * (if such a driver exists at all). Apparently related to this hardware 95 * limitation, "Designing Cards and Drivers", p. 9-8, says that a slot 96 * interrupt with no driver would crash MacOS (the book was written before 97 * the appearance of Macs with RBV or OSS). 98 */ 99 100 static u8 nubus_disabled; 101 102 void via_debug_dump(void); 103 static void via_nubus_init(void); 104 105 /* 106 * Initialize the VIAs 107 * 108 * First we figure out where they actually _are_ as well as what type of 109 * VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.) 110 * Then we pretty much clear them out and disable all IRQ sources. 111 */ 112 113 void __init via_init(void) 114 { 115 via1 = (void *)VIA1_BASE; 116 pr_debug("VIA1 detected at %p\n", via1); 117 118 if (oss_present) { 119 via2 = NULL; 120 rbv_present = 0; 121 } else { 122 switch (macintosh_config->via_type) { 123 124 /* IIci, IIsi, IIvx, IIvi (P6xx), LC series */ 125 126 case MAC_VIA_IICI: 127 via2 = (void *)RBV_BASE; 128 pr_debug("VIA2 (RBV) detected at %p\n", via2); 129 rbv_present = 1; 130 if (macintosh_config->ident == MAC_MODEL_LCIII) { 131 rbv_clear = 0x00; 132 } else { 133 /* on most RBVs (& unlike the VIAs), you */ 134 /* need to set bit 7 when you write to IFR */ 135 /* in order for your clear to occur. */ 136 rbv_clear = 0x80; 137 } 138 gIER = rIER; 139 gIFR = rIFR; 140 gBufA = rSIFR; 141 gBufB = rBufB; 142 break; 143 144 /* Quadra and early MacIIs agree on the VIA locations */ 145 146 case MAC_VIA_QUADRA: 147 case MAC_VIA_II: 148 via2 = (void *) VIA2_BASE; 149 pr_debug("VIA2 detected at %p\n", via2); 150 rbv_present = 0; 151 rbv_clear = 0x00; 152 gIER = vIER; 153 gIFR = vIFR; 154 gBufA = vBufA; 155 gBufB = vBufB; 156 break; 157 158 default: 159 panic("UNKNOWN VIA TYPE"); 160 } 161 } 162 163 #ifdef DEBUG_VIA 164 via_debug_dump(); 165 #endif 166 167 /* 168 * Shut down all IRQ sources, reset the timers, and 169 * kill the timer latch on VIA1. 170 */ 171 172 via1[vIER] = 0x7F; 173 via1[vIFR] = 0x7F; 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[vT1CL] = 0; 229 via2[vT1CH] = 0; 230 via2[vT2CL] = 0; 231 via2[vT2CH] = 0; 232 via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ 233 via2[vACR] &= ~0x03; /* disable port A & B latches */ 234 } 235 236 via_nubus_init(); 237 238 /* Everything below this point is VIA2 only... */ 239 240 if (rbv_present) 241 return; 242 243 /* 244 * Set vPCR for control line interrupts. 245 * 246 * CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger. 247 * 248 * Macs with ESP SCSI have a negative edge triggered SCSI interrupt. 249 * Testing reveals that PowerBooks do too. However, the SE/30 250 * schematic diagram shows an active high NCR5380 IRQ line. 251 */ 252 253 pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]); 254 if (macintosh_config->via_type == MAC_VIA_II) { 255 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */ 256 via2[vPCR] = 0x66; 257 } else { 258 /* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */ 259 via2[vPCR] = 0x22; 260 } 261 } 262 263 /* 264 * Debugging dump, used in various places to see what's going on. 265 */ 266 267 void via_debug_dump(void) 268 { 269 printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 270 (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]); 271 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 272 (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]); 273 if (!via2) 274 return; 275 if (rbv_present) { 276 printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n", 277 (uint) via2[rIFR], (uint) via2[rIER]); 278 printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n", 279 (uint) via2[rSIFR], (uint) via2[rSIER]); 280 } else { 281 printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", 282 (uint) via2[vDirA], (uint) via2[vDirB], 283 (uint) via2[vACR]); 284 printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", 285 (uint) via2[vPCR], 286 (uint) via2[vIFR], (uint) via2[vIER]); 287 } 288 } 289 290 /* 291 * Flush the L2 cache on Macs that have it by flipping 292 * the system into 24-bit mode for an instant. 293 */ 294 295 void via_l2_flush(int writeback) 296 { 297 unsigned long flags; 298 299 local_irq_save(flags); 300 via2[gBufB] &= ~VIA2B_vMode32; 301 via2[gBufB] |= VIA2B_vMode32; 302 local_irq_restore(flags); 303 } 304 305 /* 306 * Initialize VIA2 for Nubus access 307 */ 308 309 static void __init via_nubus_init(void) 310 { 311 /* unlock nubus transactions */ 312 313 if ((macintosh_config->adb_type != MAC_ADB_PB1) && 314 (macintosh_config->adb_type != MAC_ADB_PB2)) { 315 /* set the line to be an output on non-RBV machines */ 316 if (!rbv_present) 317 via2[vDirB] |= 0x02; 318 319 /* this seems to be an ADB bit on PMU machines */ 320 /* according to MkLinux. -- jmt */ 321 via2[gBufB] |= 0x02; 322 } 323 324 /* 325 * Disable the slot interrupts. On some hardware that's not possible. 326 * On some hardware it's unclear what all of these I/O lines do. 327 */ 328 329 switch (macintosh_config->via_type) { 330 case MAC_VIA_II: 331 case MAC_VIA_QUADRA: 332 pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]); 333 break; 334 case MAC_VIA_IICI: 335 /* RBV. Disable all the slot interrupts. SIER works like IER. */ 336 via2[rSIER] = 0x7F; 337 break; 338 } 339 } 340 341 void via_nubus_irq_startup(int irq) 342 { 343 int irq_idx = IRQ_IDX(irq); 344 345 switch (macintosh_config->via_type) { 346 case MAC_VIA_II: 347 case MAC_VIA_QUADRA: 348 /* Make the port A line an input. Probably redundant. */ 349 if (macintosh_config->via_type == MAC_VIA_II) { 350 /* The top two bits are RAM size outputs. */ 351 via2[vDirA] &= 0xC0 | ~(1 << irq_idx); 352 } else { 353 /* Allow NuBus slots 9 through F. */ 354 via2[vDirA] &= 0x80 | ~(1 << irq_idx); 355 } 356 fallthrough; 357 case MAC_VIA_IICI: 358 via_irq_enable(irq); 359 break; 360 } 361 } 362 363 void via_nubus_irq_shutdown(int irq) 364 { 365 switch (macintosh_config->via_type) { 366 case MAC_VIA_II: 367 case MAC_VIA_QUADRA: 368 /* Ensure that the umbrella CA1 interrupt remains enabled. */ 369 via_irq_enable(irq); 370 break; 371 case MAC_VIA_IICI: 372 via_irq_disable(irq); 373 break; 374 } 375 } 376 377 /* 378 * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's 379 * via6522.c :-), disable/pending masks added. 380 */ 381 382 #define VIA_TIMER_1_INT BIT(6) 383 384 void via1_irq(struct irq_desc *desc) 385 { 386 int irq_num; 387 unsigned char irq_bit, events; 388 389 events = via1[vIFR] & via1[vIER] & 0x7F; 390 if (!events) 391 return; 392 393 irq_num = IRQ_MAC_TIMER_1; 394 irq_bit = VIA_TIMER_1_INT; 395 if (events & irq_bit) { 396 unsigned long flags; 397 398 local_irq_save(flags); 399 via1[vIFR] = irq_bit; 400 generic_handle_irq(irq_num); 401 local_irq_restore(flags); 402 403 events &= ~irq_bit; 404 if (!events) 405 return; 406 } 407 408 irq_num = VIA1_SOURCE_BASE; 409 irq_bit = 1; 410 do { 411 if (events & irq_bit) { 412 via1[vIFR] = irq_bit; 413 generic_handle_irq(irq_num); 414 } 415 ++irq_num; 416 irq_bit <<= 1; 417 } while (events >= irq_bit); 418 } 419 420 static void via2_irq(struct irq_desc *desc) 421 { 422 int irq_num; 423 unsigned char irq_bit, events; 424 425 events = via2[gIFR] & via2[gIER] & 0x7F; 426 if (!events) 427 return; 428 429 irq_num = VIA2_SOURCE_BASE; 430 irq_bit = 1; 431 do { 432 if (events & irq_bit) { 433 via2[gIFR] = irq_bit | rbv_clear; 434 generic_handle_irq(irq_num); 435 } 436 ++irq_num; 437 irq_bit <<= 1; 438 } while (events >= irq_bit); 439 } 440 441 /* 442 * Dispatch Nubus interrupts. We are called as a secondary dispatch by the 443 * VIA2 dispatcher as a fast interrupt handler. 444 */ 445 446 static void via_nubus_irq(struct irq_desc *desc) 447 { 448 int slot_irq; 449 unsigned char slot_bit, events; 450 451 events = ~via2[gBufA] & 0x7F; 452 if (rbv_present) 453 events &= via2[rSIER]; 454 else 455 events &= ~via2[vDirA]; 456 if (!events) 457 return; 458 459 do { 460 slot_irq = IRQ_NUBUS_F; 461 slot_bit = 0x40; 462 do { 463 if (events & slot_bit) { 464 events &= ~slot_bit; 465 generic_handle_irq(slot_irq); 466 } 467 --slot_irq; 468 slot_bit >>= 1; 469 } while (events); 470 471 /* clear the CA1 interrupt and make certain there's no more. */ 472 via2[gIFR] = 0x02 | rbv_clear; 473 events = ~via2[gBufA] & 0x7F; 474 if (rbv_present) 475 events &= via2[rSIER]; 476 else 477 events &= ~via2[vDirA]; 478 } while (events); 479 } 480 481 /* 482 * Register the interrupt dispatchers for VIA or RBV machines only. 483 */ 484 485 void __init via_register_interrupts(void) 486 { 487 if (via_alt_mapping) { 488 /* software interrupt */ 489 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 490 /* via1 interrupt */ 491 irq_set_chained_handler(IRQ_AUTO_6, via1_irq); 492 } else { 493 irq_set_chained_handler(IRQ_AUTO_1, via1_irq); 494 } 495 irq_set_chained_handler(IRQ_AUTO_2, via2_irq); 496 irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq); 497 } 498 499 void via_irq_enable(int irq) { 500 int irq_src = IRQ_SRC(irq); 501 int irq_idx = IRQ_IDX(irq); 502 503 if (irq_src == 1) { 504 via1[vIER] = IER_SET_BIT(irq_idx); 505 } else if (irq_src == 2) { 506 if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0) 507 via2[gIER] = IER_SET_BIT(irq_idx); 508 } else if (irq_src == 7) { 509 switch (macintosh_config->via_type) { 510 case MAC_VIA_II: 511 case MAC_VIA_QUADRA: 512 nubus_disabled &= ~(1 << irq_idx); 513 /* Enable the CA1 interrupt when no slot is disabled. */ 514 if (!nubus_disabled) 515 via2[gIER] = IER_SET_BIT(1); 516 break; 517 case MAC_VIA_IICI: 518 /* On RBV, enable the slot interrupt. 519 * SIER works like IER. 520 */ 521 via2[rSIER] = IER_SET_BIT(irq_idx); 522 break; 523 } 524 } 525 } 526 527 void via_irq_disable(int irq) { 528 int irq_src = IRQ_SRC(irq); 529 int irq_idx = IRQ_IDX(irq); 530 531 if (irq_src == 1) { 532 via1[vIER] = IER_CLR_BIT(irq_idx); 533 } else if (irq_src == 2) { 534 via2[gIER] = IER_CLR_BIT(irq_idx); 535 } else if (irq_src == 7) { 536 switch (macintosh_config->via_type) { 537 case MAC_VIA_II: 538 case MAC_VIA_QUADRA: 539 nubus_disabled |= 1 << irq_idx; 540 if (nubus_disabled) 541 via2[gIER] = IER_CLR_BIT(1); 542 break; 543 case MAC_VIA_IICI: 544 via2[rSIER] = IER_CLR_BIT(irq_idx); 545 break; 546 } 547 } 548 } 549 550 void via1_set_head(int head) 551 { 552 if (head == 0) 553 via1[vBufA] &= ~VIA1A_vHeadSel; 554 else 555 via1[vBufA] |= VIA1A_vHeadSel; 556 } 557 EXPORT_SYMBOL(via1_set_head); 558 559 int via2_scsi_drq_pending(void) 560 { 561 return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ)); 562 } 563 EXPORT_SYMBOL(via2_scsi_drq_pending); 564 565 /* timer and clock source */ 566 567 #define VIA_CLOCK_FREQ 783360 /* VIA "phase 2" clock in Hz */ 568 #define VIA_TIMER_CYCLES (VIA_CLOCK_FREQ / HZ) /* clock cycles per jiffy */ 569 570 #define VIA_TC (VIA_TIMER_CYCLES - 2) /* including 0 and -1 */ 571 #define VIA_TC_LOW (VIA_TC & 0xFF) 572 #define VIA_TC_HIGH (VIA_TC >> 8) 573 574 static u64 mac_read_clk(struct clocksource *cs); 575 576 static struct clocksource mac_clk = { 577 .name = "via1", 578 .rating = 250, 579 .read = mac_read_clk, 580 .mask = CLOCKSOURCE_MASK(32), 581 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 582 }; 583 584 static u32 clk_total, clk_offset; 585 586 static irqreturn_t via_timer_handler(int irq, void *dev_id) 587 { 588 clk_total += VIA_TIMER_CYCLES; 589 clk_offset = 0; 590 legacy_timer_tick(1); 591 592 return IRQ_HANDLED; 593 } 594 595 void __init via_init_clock(void) 596 { 597 if (request_irq(IRQ_MAC_TIMER_1, via_timer_handler, IRQF_TIMER, "timer", 598 NULL)) { 599 pr_err("Couldn't register %s interrupt\n", "timer"); 600 return; 601 } 602 603 via1[vT1CL] = VIA_TC_LOW; 604 via1[vT1CH] = VIA_TC_HIGH; 605 via1[vACR] |= 0x40; 606 607 clocksource_register_hz(&mac_clk, VIA_CLOCK_FREQ); 608 } 609 610 static u64 mac_read_clk(struct clocksource *cs) 611 { 612 unsigned long flags; 613 u8 count_high; 614 u16 count; 615 u32 ticks; 616 617 /* 618 * Timer counter wrap-around is detected with the timer interrupt flag 619 * but reading the counter low byte (vT1CL) would reset the flag. 620 * Also, accessing both counter registers is essentially a data race. 621 * These problems are avoided by ignoring the low byte. Clock accuracy 622 * is 256 times worse (error can reach 0.327 ms) but CPU overhead is 623 * reduced by avoiding slow VIA register accesses. 624 */ 625 626 local_irq_save(flags); 627 count_high = via1[vT1CH]; 628 if (count_high == 0xFF) 629 count_high = 0; 630 if (count_high > 0 && (via1[vIFR] & VIA_TIMER_1_INT)) 631 clk_offset = VIA_TIMER_CYCLES; 632 count = count_high << 8; 633 ticks = VIA_TIMER_CYCLES - count; 634 ticks += clk_offset + clk_total; 635 local_irq_restore(flags); 636 637 return ticks; 638 } 639