647 lines
17 KiB
C
647 lines
17 KiB
C
/*
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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. <cananian@alumni.princeton.edu> 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 (funaho@jurai.org)
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*
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*/
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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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* 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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* 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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/*
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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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* Note: the OSS is actually "detected" here and not in oss_init(). It just
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* seems more logical to do it here since via_init() needs to know
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* these things anyways.
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*/
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void __init via_init(void)
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{
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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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via1 = (void *) VIA1_BASE;
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if (macintosh_config->ident == MAC_MODEL_IIFX) {
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via2 = NULL;
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rbv_present = 0;
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oss_present = 1;
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} else {
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via2 = (void *) RBV_BASE;
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rbv_present = 1;
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oss_present = 0;
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}
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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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via1 = (void *) VIA1_BASE;
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via2 = (void *) VIA2_BASE;
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rbv_present = 0;
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oss_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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printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1);
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printk(KERN_INFO "VIA2 at %p is ", via2);
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if (rbv_present) {
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printk("an RBV\n");
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} else if (oss_present) {
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printk("an OSS\n");
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} else {
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printk("a 6522 or clone\n");
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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[vT1LL] = 0;
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via1[vT1LH] = 0;
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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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* XXX: testing for SE/30 VBL
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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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/*
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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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/* 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[vT1LL] = 0;
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via2[vT1LH] = 0;
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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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/* 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 (oss_present) {
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printk(KERN_DEBUG "VIA2: <OSS>\n");
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} else 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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* Return the status of the L2 cache on a IIci
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*/
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int via_get_cache_disable(void)
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{
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/* Safeguard against being called accidentally */
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if (!via2) {
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printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n");
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return 1;
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}
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return (int) via2[gBufB] & VIA2B_vCDis;
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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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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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/* fall through */
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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) {
|
|
events &= ~slot_bit;
|
|
generic_handle_irq(slot_irq);
|
|
}
|
|
--slot_irq;
|
|
slot_bit >>= 1;
|
|
} while (events);
|
|
|
|
/* clear the CA1 interrupt and make certain there's no more. */
|
|
via2[gIFR] = 0x02 | rbv_clear;
|
|
events = ~via2[gBufA] & 0x7F;
|
|
if (rbv_present)
|
|
events &= via2[rSIER];
|
|
else
|
|
events &= ~via2[vDirA];
|
|
} while (events);
|
|
}
|
|
|
|
/*
|
|
* Register the interrupt dispatchers for VIA or RBV machines only.
|
|
*/
|
|
|
|
void __init via_register_interrupts(void)
|
|
{
|
|
if (via_alt_mapping) {
|
|
/* software interrupt */
|
|
irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
|
|
/* via1 interrupt */
|
|
irq_set_chained_handler(IRQ_AUTO_6, via1_irq);
|
|
} else {
|
|
irq_set_chained_handler(IRQ_AUTO_1, via1_irq);
|
|
}
|
|
irq_set_chained_handler(IRQ_AUTO_2, via2_irq);
|
|
irq_set_chained_handler(IRQ_MAC_NUBUS, via_nubus_irq);
|
|
}
|
|
|
|
void via_irq_enable(int irq) {
|
|
int irq_src = IRQ_SRC(irq);
|
|
int irq_idx = IRQ_IDX(irq);
|
|
|
|
#ifdef DEBUG_IRQUSE
|
|
printk(KERN_DEBUG "via_irq_enable(%d)\n", irq);
|
|
#endif
|
|
|
|
if (irq_src == 1) {
|
|
via1[vIER] = IER_SET_BIT(irq_idx);
|
|
} else if (irq_src == 2) {
|
|
if (irq != IRQ_MAC_NUBUS || nubus_disabled == 0)
|
|
via2[gIER] = IER_SET_BIT(irq_idx);
|
|
} else if (irq_src == 7) {
|
|
switch (macintosh_config->via_type) {
|
|
case MAC_VIA_II:
|
|
case MAC_VIA_QUADRA:
|
|
nubus_disabled &= ~(1 << irq_idx);
|
|
/* Enable the CA1 interrupt when no slot is disabled. */
|
|
if (!nubus_disabled)
|
|
via2[gIER] = IER_SET_BIT(1);
|
|
break;
|
|
case MAC_VIA_IICI:
|
|
/* On RBV, enable the slot interrupt.
|
|
* SIER works like IER.
|
|
*/
|
|
via2[rSIER] = IER_SET_BIT(irq_idx);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void via_irq_disable(int irq) {
|
|
int irq_src = IRQ_SRC(irq);
|
|
int irq_idx = IRQ_IDX(irq);
|
|
|
|
#ifdef DEBUG_IRQUSE
|
|
printk(KERN_DEBUG "via_irq_disable(%d)\n", irq);
|
|
#endif
|
|
|
|
if (irq_src == 1) {
|
|
via1[vIER] = IER_CLR_BIT(irq_idx);
|
|
} else if (irq_src == 2) {
|
|
via2[gIER] = IER_CLR_BIT(irq_idx);
|
|
} else if (irq_src == 7) {
|
|
switch (macintosh_config->via_type) {
|
|
case MAC_VIA_II:
|
|
case MAC_VIA_QUADRA:
|
|
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_INTERVAL (1000000 / HZ) /* microseconds per jiffy */
|
|
#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)
|
|
|
|
void __init via_init_clock(irq_handler_t timer_routine)
|
|
{
|
|
if (request_irq(IRQ_MAC_TIMER_1, timer_routine, 0, "timer", NULL)) {
|
|
pr_err("Couldn't register %s interrupt\n", "timer");
|
|
return;
|
|
}
|
|
|
|
via1[vT1LL] = VIA_TC_LOW;
|
|
via1[vT1LH] = VIA_TC_HIGH;
|
|
via1[vT1CL] = VIA_TC_LOW;
|
|
via1[vT1CH] = VIA_TC_HIGH;
|
|
via1[vACR] |= 0x40;
|
|
}
|
|
|
|
u32 mac_gettimeoffset(void)
|
|
{
|
|
unsigned long flags;
|
|
u8 count_high;
|
|
u16 count, offset = 0;
|
|
|
|
/*
|
|
* 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))
|
|
offset = VIA_TIMER_CYCLES;
|
|
local_irq_restore(flags);
|
|
|
|
count = count_high << 8;
|
|
count = VIA_TIMER_CYCLES - count + offset;
|
|
|
|
return ((count * VIA_TIMER_INTERVAL) / VIA_TIMER_CYCLES) * 1000;
|
|
}
|