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636 lines
16 KiB
636 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* 6522 Versatile Interface Adapter (VIA) |
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* |
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* There are two of these on the Mac II. Some IRQs are vectored |
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* via them as are assorted bits and bobs - eg RTC, ADB. |
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* |
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* CSA: Motorola seems to have removed documentation on the 6522 from |
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* their web site; try |
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* http://nerini.drf.com/vectrex/other/text/chips/6522/ |
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* http://www.zymurgy.net/classic/vic20/vicdet1.htm |
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* and |
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* http://193.23.168.87/mikro_laborversuche/via_iobaustein/via6522_1.html |
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* for info. A full-text web search on 6522 AND VIA will probably also |
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* net some usefulness. <[email protected]> 20apr1999 |
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* |
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* Additional data is here (the SY6522 was used in the Mac II etc): |
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* http://www.6502.org/documents/datasheets/synertek/synertek_sy6522.pdf |
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* http://www.6502.org/documents/datasheets/synertek/synertek_sy6522_programming_reference.pdf |
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* |
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* PRAM/RTC access algorithms are from the NetBSD RTC toolkit version 1.08b |
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* by Erik Vogan and adapted to Linux by Joshua M. Thompson ([email protected]) |
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* |
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*/ |
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#include <linux/clocksource.h> |
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/mm.h> |
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#include <linux/delay.h> |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/irq.h> |
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#include <asm/macintosh.h> |
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#include <asm/macints.h> |
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#include <asm/mac_via.h> |
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#include <asm/mac_psc.h> |
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#include <asm/mac_oss.h> |
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volatile __u8 *via1, *via2; |
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int rbv_present; |
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int via_alt_mapping; |
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EXPORT_SYMBOL(via_alt_mapping); |
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static __u8 rbv_clear; |
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|
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/* |
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* Globals for accessing the VIA chip registers without having to |
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* check if we're hitting a real VIA or an RBV. Normally you could |
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* just hit the combined register (ie, vIER|rIER) but that seems to |
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* break on AV Macs...probably because they actually decode more than |
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* eight address bits. Why can't Apple engineers at least be |
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* _consistently_ lazy? - 1999-05-21 (jmt) |
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*/ |
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static int gIER,gIFR,gBufA,gBufB; |
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|
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/* |
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* On Macs with a genuine VIA chip there is no way to mask an individual slot |
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* interrupt. This limitation also seems to apply to VIA clone logic cores in |
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* Quadra-like ASICs. (RBV and OSS machines don't have this limitation.) |
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* |
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* We used to fake it by configuring the relevant VIA pin as an output |
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* (to mask the interrupt) or input (to unmask). That scheme did not work on |
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* (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector |
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* circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE, |
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* p. 10-11 etc) but VIA outputs are not (see datasheet). |
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* |
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* Driving these outputs high must cause the VIA to source current and the |
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* card to sink current when it asserts /NMRQ. Current will flow but the pin |
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* voltage is uncertain and so the /NMRQ condition may still cause a transition |
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* at the VIA2 CA1 input (which explains the lost interrupts). A side effect |
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* is that a disabled slot IRQ can never be tested as pending or not. |
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* |
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* Driving these outputs low doesn't work either. All the slot /NMRQ lines are |
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* (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see |
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* The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a |
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* disabled /NMRQ line low, the falling edge immediately triggers a CA1 |
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* interrupt and all slot interrupts after that will generate no transition |
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* and therefore no interrupt, even after being re-enabled. |
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* |
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* So we make the VIA port A I/O lines inputs and use nubus_disabled to keep |
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* track of their states. When any slot IRQ becomes disabled we mask the CA1 |
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* umbrella interrupt. Only when all slot IRQs become enabled do we unmask |
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* the CA1 interrupt. It must remain enabled even when cards have no interrupt |
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* handler registered. Drivers must therefore disable a slot interrupt at the |
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* device before they call free_irq (like shared and autovector interrupts). |
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* |
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* There is also a related problem when MacOS is used to boot Linux. A network |
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* card brought up by a MacOS driver may raise an interrupt while Linux boots. |
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* This can be fatal since it can't be handled until the right driver loads |
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* (if such a driver exists at all). Apparently related to this hardware |
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* limitation, "Designing Cards and Drivers", p. 9-8, says that a slot |
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* interrupt with no driver would crash MacOS (the book was written before |
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* the appearance of Macs with RBV or OSS). |
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*/ |
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static u8 nubus_disabled; |
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void via_debug_dump(void); |
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static void via_nubus_init(void); |
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/* |
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* Initialize the VIAs |
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* |
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* First we figure out where they actually _are_ as well as what type of |
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* VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.) |
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* Then we pretty much clear them out and disable all IRQ sources. |
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*/ |
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void __init via_init(void) |
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{ |
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via1 = (void *)VIA1_BASE; |
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pr_debug("VIA1 detected at %p\n", via1); |
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if (oss_present) { |
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via2 = NULL; |
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rbv_present = 0; |
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} else { |
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switch (macintosh_config->via_type) { |
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/* IIci, IIsi, IIvx, IIvi (P6xx), LC series */ |
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case MAC_VIA_IICI: |
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via2 = (void *)RBV_BASE; |
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pr_debug("VIA2 (RBV) detected at %p\n", via2); |
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rbv_present = 1; |
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if (macintosh_config->ident == MAC_MODEL_LCIII) { |
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rbv_clear = 0x00; |
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} else { |
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/* on most RBVs (& unlike the VIAs), you */ |
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/* need to set bit 7 when you write to IFR */ |
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/* in order for your clear to occur. */ |
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rbv_clear = 0x80; |
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} |
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gIER = rIER; |
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gIFR = rIFR; |
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gBufA = rSIFR; |
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gBufB = rBufB; |
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break; |
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/* Quadra and early MacIIs agree on the VIA locations */ |
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case MAC_VIA_QUADRA: |
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case MAC_VIA_II: |
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via2 = (void *) VIA2_BASE; |
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pr_debug("VIA2 detected at %p\n", via2); |
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rbv_present = 0; |
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rbv_clear = 0x00; |
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gIER = vIER; |
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gIFR = vIFR; |
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gBufA = vBufA; |
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gBufB = vBufB; |
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break; |
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default: |
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panic("UNKNOWN VIA TYPE"); |
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} |
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} |
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#ifdef DEBUG_VIA |
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via_debug_dump(); |
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#endif |
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/* |
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* Shut down all IRQ sources, reset the timers, and |
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* kill the timer latch on VIA1. |
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*/ |
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via1[vIER] = 0x7F; |
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via1[vIFR] = 0x7F; |
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via1[vT1CL] = 0; |
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via1[vT1CH] = 0; |
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via1[vT2CL] = 0; |
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via1[vT2CH] = 0; |
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via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ |
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via1[vACR] &= ~0x03; /* disable port A & B latches */ |
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/* |
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* SE/30: disable video IRQ |
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*/ |
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if (macintosh_config->ident == MAC_MODEL_SE30) { |
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via1[vDirB] |= 0x40; |
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via1[vBufB] |= 0x40; |
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} |
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switch (macintosh_config->adb_type) { |
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case MAC_ADB_IOP: |
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case MAC_ADB_II: |
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case MAC_ADB_PB1: |
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/* |
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* Set the RTC bits to a known state: all lines to outputs and |
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* RTC disabled (yes that's 0 to enable and 1 to disable). |
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*/ |
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via1[vDirB] |= VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData; |
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via1[vBufB] |= VIA1B_vRTCEnb | VIA1B_vRTCClk; |
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break; |
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} |
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/* Everything below this point is VIA2/RBV only... */ |
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if (oss_present) |
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return; |
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if ((macintosh_config->via_type == MAC_VIA_QUADRA) && |
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(macintosh_config->adb_type != MAC_ADB_PB1) && |
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(macintosh_config->adb_type != MAC_ADB_PB2) && |
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(macintosh_config->ident != MAC_MODEL_C660) && |
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(macintosh_config->ident != MAC_MODEL_Q840)) { |
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via_alt_mapping = 1; |
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via1[vDirB] |= 0x40; |
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via1[vBufB] &= ~0x40; |
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} else { |
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via_alt_mapping = 0; |
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} |
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/* |
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* Now initialize VIA2. For RBV we just kill all interrupts; |
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* for a regular VIA we also reset the timers and stuff. |
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*/ |
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via2[gIER] = 0x7F; |
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via2[gIFR] = 0x7F | rbv_clear; |
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if (!rbv_present) { |
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via2[vT1CL] = 0; |
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via2[vT1CH] = 0; |
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via2[vT2CL] = 0; |
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via2[vT2CH] = 0; |
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via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */ |
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via2[vACR] &= ~0x03; /* disable port A & B latches */ |
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} |
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via_nubus_init(); |
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/* Everything below this point is VIA2 only... */ |
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if (rbv_present) |
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return; |
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/* |
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* Set vPCR for control line interrupts. |
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* |
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* CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger. |
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* |
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* Macs with ESP SCSI have a negative edge triggered SCSI interrupt. |
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* Testing reveals that PowerBooks do too. However, the SE/30 |
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* schematic diagram shows an active high NCR5380 IRQ line. |
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*/ |
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pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]); |
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if (macintosh_config->via_type == MAC_VIA_II) { |
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/* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */ |
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via2[vPCR] = 0x66; |
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} else { |
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/* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */ |
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via2[vPCR] = 0x22; |
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} |
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} |
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/* |
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* Debugging dump, used in various places to see what's going on. |
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*/ |
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void via_debug_dump(void) |
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{ |
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printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", |
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(uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]); |
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printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", |
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(uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]); |
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if (!via2) |
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return; |
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if (rbv_present) { |
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printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n", |
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(uint) via2[rIFR], (uint) via2[rIER]); |
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printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n", |
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(uint) via2[rSIFR], (uint) via2[rSIER]); |
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} else { |
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printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n", |
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(uint) via2[vDirA], (uint) via2[vDirB], |
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(uint) via2[vACR]); |
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printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n", |
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(uint) via2[vPCR], |
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(uint) via2[vIFR], (uint) via2[vIER]); |
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} |
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} |
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/* |
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* Flush the L2 cache on Macs that have it by flipping |
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* the system into 24-bit mode for an instant. |
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*/ |
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void via_l2_flush(int writeback) |
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{ |
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unsigned long flags; |
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local_irq_save(flags); |
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via2[gBufB] &= ~VIA2B_vMode32; |
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via2[gBufB] |= VIA2B_vMode32; |
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local_irq_restore(flags); |
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} |
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/* |
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* Initialize VIA2 for Nubus access |
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*/ |
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static void __init via_nubus_init(void) |
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{ |
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/* unlock nubus transactions */ |
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if ((macintosh_config->adb_type != MAC_ADB_PB1) && |
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(macintosh_config->adb_type != MAC_ADB_PB2)) { |
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/* set the line to be an output on non-RBV machines */ |
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if (!rbv_present) |
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via2[vDirB] |= 0x02; |
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/* this seems to be an ADB bit on PMU machines */ |
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/* according to MkLinux. -- jmt */ |
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via2[gBufB] |= 0x02; |
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} |
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/* |
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* Disable the slot interrupts. On some hardware that's not possible. |
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* On some hardware it's unclear what all of these I/O lines do. |
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*/ |
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switch (macintosh_config->via_type) { |
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case MAC_VIA_II: |
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case MAC_VIA_QUADRA: |
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pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]); |
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break; |
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case MAC_VIA_IICI: |
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/* RBV. Disable all the slot interrupts. SIER works like IER. */ |
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via2[rSIER] = 0x7F; |
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break; |
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} |
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} |
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void via_nubus_irq_startup(int irq) |
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{ |
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int irq_idx = IRQ_IDX(irq); |
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switch (macintosh_config->via_type) { |
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case MAC_VIA_II: |
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case MAC_VIA_QUADRA: |
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/* Make the port A line an input. Probably redundant. */ |
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if (macintosh_config->via_type == MAC_VIA_II) { |
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/* The top two bits are RAM size outputs. */ |
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via2[vDirA] &= 0xC0 | ~(1 << irq_idx); |
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} else { |
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/* Allow NuBus slots 9 through F. */ |
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via2[vDirA] &= 0x80 | ~(1 << irq_idx); |
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} |
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fallthrough; |
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case MAC_VIA_IICI: |
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via_irq_enable(irq); |
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break; |
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} |
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} |
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void via_nubus_irq_shutdown(int irq) |
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{ |
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switch (macintosh_config->via_type) { |
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case MAC_VIA_II: |
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case MAC_VIA_QUADRA: |
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/* Ensure that the umbrella CA1 interrupt remains enabled. */ |
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via_irq_enable(irq); |
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break; |
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case MAC_VIA_IICI: |
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via_irq_disable(irq); |
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break; |
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} |
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} |
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/* |
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* The generic VIA interrupt routines (shamelessly stolen from Alan Cox's |
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* via6522.c :-), disable/pending masks added. |
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*/ |
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#define VIA_TIMER_1_INT BIT(6) |
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void via1_irq(struct irq_desc *desc) |
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{ |
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int irq_num; |
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unsigned char irq_bit, events; |
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events = via1[vIFR] & via1[vIER] & 0x7F; |
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if (!events) |
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return; |
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irq_num = IRQ_MAC_TIMER_1; |
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irq_bit = VIA_TIMER_1_INT; |
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if (events & irq_bit) { |
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unsigned long flags; |
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local_irq_save(flags); |
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via1[vIFR] = irq_bit; |
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generic_handle_irq(irq_num); |
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local_irq_restore(flags); |
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events &= ~irq_bit; |
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if (!events) |
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return; |
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} |
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irq_num = VIA1_SOURCE_BASE; |
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irq_bit = 1; |
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do { |
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if (events & irq_bit) { |
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via1[vIFR] = irq_bit; |
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generic_handle_irq(irq_num); |
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} |
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++irq_num; |
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irq_bit <<= 1; |
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} while (events >= irq_bit); |
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} |
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static void via2_irq(struct irq_desc *desc) |
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{ |
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int irq_num; |
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unsigned char irq_bit, events; |
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events = via2[gIFR] & via2[gIER] & 0x7F; |
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if (!events) |
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return; |
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irq_num = VIA2_SOURCE_BASE; |
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irq_bit = 1; |
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do { |
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if (events & irq_bit) { |
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via2[gIFR] = irq_bit | rbv_clear; |
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generic_handle_irq(irq_num); |
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} |
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++irq_num; |
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irq_bit <<= 1; |
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} while (events >= irq_bit); |
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} |
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/* |
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* Dispatch Nubus interrupts. We are called as a secondary dispatch by the |
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* VIA2 dispatcher as a fast interrupt handler. |
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*/ |
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static void via_nubus_irq(struct irq_desc *desc) |
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{ |
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int slot_irq; |
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unsigned char slot_bit, events; |
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events = ~via2[gBufA] & 0x7F; |
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if (rbv_present) |
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events &= via2[rSIER]; |
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else |
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events &= ~via2[vDirA]; |
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if (!events) |
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return; |
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do { |
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slot_irq = IRQ_NUBUS_F; |
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slot_bit = 0x40; |
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do { |
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if (events & slot_bit) { |
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events &= ~slot_bit; |
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generic_handle_irq(slot_irq); |
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} |
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--slot_irq; |
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slot_bit >>= 1; |
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} while (events); |
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/* clear the CA1 interrupt and make certain there's no more. */ |
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via2[gIFR] = 0x02 | rbv_clear; |
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events = ~via2[gBufA] & 0x7F; |
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if (rbv_present) |
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events &= via2[rSIER]; |
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else |
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events &= ~via2[vDirA]; |
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} while (events); |
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} |
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/* |
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* Register the interrupt dispatchers for VIA or RBV machines only. |
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*/ |
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void __init via_register_interrupts(void) |
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{ |
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if (via_alt_mapping) { |
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/* software interrupt */ |
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irq_set_chained_handler(IRQ_AUTO_1, via1_irq); |
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/* via1 interrupt */ |
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irq_set_chained_handler(IRQ_AUTO_6, via1_irq); |
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} else { |
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irq_set_chained_handler(IRQ_AUTO_1, via1_irq); |
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} |
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irq_set_chained_handler(IRQ_AUTO_2, via2_irq); |
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irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq); |
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} |
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void via_irq_enable(int irq) { |
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int irq_src = IRQ_SRC(irq); |
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int irq_idx = IRQ_IDX(irq); |
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if (irq_src == 1) { |
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via1[vIER] = IER_SET_BIT(irq_idx); |
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} else if (irq_src == 2) { |
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if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0) |
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via2[gIER] = IER_SET_BIT(irq_idx); |
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} else if (irq_src == 7) { |
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switch (macintosh_config->via_type) { |
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case MAC_VIA_II: |
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case MAC_VIA_QUADRA: |
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nubus_disabled &= ~(1 << irq_idx); |
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/* Enable the CA1 interrupt when no slot is disabled. */ |
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if (!nubus_disabled) |
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via2[gIER] = IER_SET_BIT(1); |
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break; |
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case MAC_VIA_IICI: |
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/* On RBV, enable the slot interrupt. |
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* SIER works like IER. |
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*/ |
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via2[rSIER] = IER_SET_BIT(irq_idx); |
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break; |
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} |
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} |
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} |
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void via_irq_disable(int irq) { |
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int irq_src = IRQ_SRC(irq); |
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int irq_idx = IRQ_IDX(irq); |
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if (irq_src == 1) { |
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via1[vIER] = IER_CLR_BIT(irq_idx); |
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} else if (irq_src == 2) { |
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via2[gIER] = IER_CLR_BIT(irq_idx); |
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} else if (irq_src == 7) { |
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switch (macintosh_config->via_type) { |
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case MAC_VIA_II: |
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case MAC_VIA_QUADRA: |
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nubus_disabled |= 1 << irq_idx; |
|
if (nubus_disabled) |
|
via2[gIER] = IER_CLR_BIT(1); |
|
break; |
|
case MAC_VIA_IICI: |
|
via2[rSIER] = IER_CLR_BIT(irq_idx); |
|
break; |
|
} |
|
} |
|
} |
|
|
|
void via1_set_head(int head) |
|
{ |
|
if (head == 0) |
|
via1[vBufA] &= ~VIA1A_vHeadSel; |
|
else |
|
via1[vBufA] |= VIA1A_vHeadSel; |
|
} |
|
EXPORT_SYMBOL(via1_set_head); |
|
|
|
int via2_scsi_drq_pending(void) |
|
{ |
|
return via2[gIFR] & (1 << IRQ_IDX(IRQ_MAC_SCSIDRQ)); |
|
} |
|
EXPORT_SYMBOL(via2_scsi_drq_pending); |
|
|
|
/* timer and clock source */ |
|
|
|
#define VIA_CLOCK_FREQ 783360 /* VIA "phase 2" clock in Hz */ |
|
#define VIA_TIMER_CYCLES (VIA_CLOCK_FREQ / HZ) /* clock cycles per jiffy */ |
|
|
|
#define VIA_TC (VIA_TIMER_CYCLES - 2) /* including 0 and -1 */ |
|
#define VIA_TC_LOW (VIA_TC & 0xFF) |
|
#define VIA_TC_HIGH (VIA_TC >> 8) |
|
|
|
static u64 mac_read_clk(struct clocksource *cs); |
|
|
|
static struct clocksource mac_clk = { |
|
.name = "via1", |
|
.rating = 250, |
|
.read = mac_read_clk, |
|
.mask = CLOCKSOURCE_MASK(32), |
|
.flags = CLOCK_SOURCE_IS_CONTINUOUS, |
|
}; |
|
|
|
static u32 clk_total, clk_offset; |
|
|
|
static irqreturn_t via_timer_handler(int irq, void *dev_id) |
|
{ |
|
clk_total += VIA_TIMER_CYCLES; |
|
clk_offset = 0; |
|
legacy_timer_tick(1); |
|
|
|
return IRQ_HANDLED; |
|
} |
|
|
|
void __init via_init_clock(void) |
|
{ |
|
if (request_irq(IRQ_MAC_TIMER_1, via_timer_handler, IRQF_TIMER, "timer", |
|
NULL)) { |
|
pr_err("Couldn't register %s interrupt\n", "timer"); |
|
return; |
|
} |
|
|
|
via1[vT1CL] = VIA_TC_LOW; |
|
via1[vT1CH] = VIA_TC_HIGH; |
|
via1[vACR] |= 0x40; |
|
|
|
clocksource_register_hz(&mac_clk, VIA_CLOCK_FREQ); |
|
} |
|
|
|
static u64 mac_read_clk(struct clocksource *cs) |
|
{ |
|
unsigned long flags; |
|
u8 count_high; |
|
u16 count; |
|
u32 ticks; |
|
|
|
/* |
|
* Timer counter wrap-around is detected with the timer interrupt flag |
|
* but reading the counter low byte (vT1CL) would reset the flag. |
|
* Also, accessing both counter registers is essentially a data race. |
|
* These problems are avoided by ignoring the low byte. Clock accuracy |
|
* is 256 times worse (error can reach 0.327 ms) but CPU overhead is |
|
* reduced by avoiding slow VIA register accesses. |
|
*/ |
|
|
|
local_irq_save(flags); |
|
count_high = via1[vT1CH]; |
|
if (count_high == 0xFF) |
|
count_high = 0; |
|
if (count_high > 0 && (via1[vIFR] & VIA_TIMER_1_INT)) |
|
clk_offset = VIA_TIMER_CYCLES; |
|
count = count_high << 8; |
|
ticks = VIA_TIMER_CYCLES - count; |
|
ticks += clk_offset + clk_total; |
|
local_irq_restore(flags); |
|
|
|
return ticks; |
|
}
|
|
|