/*
* 6522 Versatile Interface Adapter (VIA)
*
* There are two of these on the Mac II. Some IRQs are vectored
* via them as are assorted bits and bobs - eg RTC, ADB.
*
* CSA: Motorola seems to have removed documentation on the 6522 from
* their web site; try
* http://nerini.drf.com/vectrex/other/text/chips/6522/
* http://www.zymurgy.net/classic/vic20/vicdet1.htm
* and
* http://193.23.168.87/mikro_laborversuche/via_iobaustein/via6522_1.html
* for info. A full-text web search on 6522 AND VIA will probably also
* net some usefulness. <cananian@alumni.princeton.edu> 20apr1999
*
* Additional data is here (the SY6522 was used in the Mac II etc):
* http://www.6502.org/documents/datasheets/synertek/synertek_sy6522.pdf
* http://www.6502.org/documents/datasheets/synertek/synertek_sy6522_programming_reference.pdf
*
* PRAM/RTC access algorithms are from the NetBSD RTC toolkit version 1.08b
* by Erik Vogan and adapted to Linux by Joshua M. Thompson (funaho@jurai.org)
*
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/irq.h>
#include <asm/bootinfo.h>
#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/mac_via.h>
#include <asm/mac_psc.h>
#include <asm/mac_oss.h>
volatile __u8 *via1, *via2;
int rbv_present;
int via_alt_mapping;
EXPORT_SYMBOL(via_alt_mapping);
static __u8 rbv_clear;
/*
* Globals for accessing the VIA chip registers without having to
* check if we're hitting a real VIA or an RBV. Normally you could
* just hit the combined register (ie, vIER|rIER) but that seems to
* break on AV Macs...probably because they actually decode more than
* eight address bits. Why can't Apple engineers at least be
* _consistently_ lazy? - 1999-05-21 (jmt)
*/
static int gIER,gIFR,gBufA,gBufB;
/*
* Timer defs.
*/
#define TICK_SIZE 10000
#define MAC_CLOCK_TICK (783300/HZ) /* ticks per HZ */
#define MAC_CLOCK_LOW (MAC_CLOCK_TICK&0xFF)
#define MAC_CLOCK_HIGH (MAC_CLOCK_TICK>>8)
/*
* On Macs with a genuine VIA chip there is no way to mask an individual slot
* interrupt. This limitation also seems to apply to VIA clone logic cores in
* Quadra-like ASICs. (RBV and OSS machines don't have this limitation.)
*
* We used to fake it by configuring the relevent VIA pin as an output
* (to mask the interrupt) or input (to unmask). That scheme did not work on
* (at least) the Quadra 700. A NuBus card's /NMRQ signal is an open-collector
* circuit (see Designing Cards and Drivers for Macintosh II and Macintosh SE,
* p. 10-11 etc) but VIA outputs are not (see datasheet).
*
* Driving these outputs high must cause the VIA to source current and the
* card to sink current when it asserts /NMRQ. Current will flow but the pin
* voltage is uncertain and so the /NMRQ condition may still cause a transition
* at the VIA2 CA1 input (which explains the lost interrupts). A side effect
* is that a disabled slot IRQ can never be tested as pending or not.
*
* Driving these outputs low doesn't work either. All the slot /NMRQ lines are
* (active low) OR'd together to generate the CA1 (aka "SLOTS") interrupt (see
* The Guide To Macintosh Family Hardware, 2nd edition p. 167). If we drive a
* disabled /NMRQ line low, the falling edge immediately triggers a CA1
* interrupt and all slot interrupts after that will generate no transition
* and therefore no interrupt, even after being re-enabled.
*
* So we make the VIA port A I/O lines inputs and use nubus_disabled to keep
* track of their states. When any slot IRQ becomes disabled we mask the CA1
* umbrella interrupt. Only when all slot IRQs become enabled do we unmask
* the CA1 interrupt. It must remain enabled even when cards have no interrupt
* handler registered. Drivers must therefore disable a slot interrupt at the
* device before they call free_irq (like shared and autovector interrupts).
*
* There is also a related problem when MacOS is used to boot Linux. A network
* card brought up by a MacOS driver may raise an interrupt while Linux boots.
* This can be fatal since it can't be handled until the right driver loads
* (if such a driver exists at all). Apparently related to this hardware
* limitation, "Designing Cards and Drivers", p. 9-8, says that a slot
* interrupt with no driver would crash MacOS (the book was written before
* the appearance of Macs with RBV or OSS).
*/
static u8 nubus_disabled;
void via_debug_dump(void);
/*
* Initialize the VIAs
*
* First we figure out where they actually _are_ as well as what type of
* VIA we have for VIA2 (it could be a real VIA or an RBV or even an OSS.)
* Then we pretty much clear them out and disable all IRQ sources.
*
* Note: the OSS is actually "detected" here and not in oss_init(). It just
* seems more logical to do it here since via_init() needs to know
* these things anyways.
*/
void __init via_init(void)
{
switch(macintosh_config->via_type) {
/* IIci, IIsi, IIvx, IIvi (P6xx), LC series */
case MAC_VIA_IICI:
via1 = (void *) VIA1_BASE;
if (macintosh_config->ident == MAC_MODEL_IIFX) {
via2 = NULL;
rbv_present = 0;
oss_present = 1;
} else {
via2 = (void *) RBV_BASE;
rbv_present = 1;
oss_present = 0;
}
if (macintosh_config->ident == MAC_MODEL_LCIII) {
rbv_clear = 0x00;
} else {
/* on most RBVs (& unlike the VIAs), you */
/* need to set bit 7 when you write to IFR */
/* in order for your clear to occur. */
rbv_clear = 0x80;
}
gIER = rIER;
gIFR = rIFR;
gBufA = rSIFR;
gBufB = rBufB;
break;
/* Quadra and early MacIIs agree on the VIA locations */
case MAC_VIA_QUADRA:
case MAC_VIA_II:
via1 = (void *) VIA1_BASE;
via2 = (void *) VIA2_BASE;
rbv_present = 0;
oss_present = 0;
rbv_clear = 0x00;
gIER = vIER;
gIFR = vIFR;
gBufA = vBufA;
gBufB = vBufB;
break;
default:
panic("UNKNOWN VIA TYPE");
}
printk(KERN_INFO "VIA1 at %p is a 6522 or clone\n", via1);
printk(KERN_INFO "VIA2 at %p is ", via2);
if (rbv_present) {
printk("an RBV\n");
} else if (oss_present) {
printk("an OSS\n");
} else {
printk("a 6522 or clone\n");
}
#ifdef DEBUG_VIA
via_debug_dump();
#endif
/*
* Shut down all IRQ sources, reset the timers, and
* kill the timer latch on VIA1.
*/
via1[vIER] = 0x7F;
via1[vIFR] = 0x7F;
via1[vT1LL] = 0;
via1[vT1LH] = 0;
via1[vT1CL] = 0;
via1[vT1CH] = 0;
via1[vT2CL] = 0;
via1[vT2CH] = 0;
via1[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
via1[vACR] &= ~0x03; /* disable port A & B latches */
/*
* SE/30: disable video IRQ
* XXX: testing for SE/30 VBL
*/
if (macintosh_config->ident == MAC_MODEL_SE30) {
via1[vDirB] |= 0x40;
via1[vBufB] |= 0x40;
}
/*
* Set the RTC bits to a known state: all lines to outputs and
* RTC disabled (yes that's 0 to enable and 1 to disable).
*/
via1[vDirB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk | VIA1B_vRTCData);
via1[vBufB] |= (VIA1B_vRTCEnb | VIA1B_vRTCClk);
/* Everything below this point is VIA2/RBV only... */
if (oss_present)
return;
if ((macintosh_config->via_type == MAC_VIA_QUADRA) &&
(macintosh_config->adb_type != MAC_ADB_PB1) &&
(macintosh_config->adb_type != MAC_ADB_PB2) &&
(macintosh_config->ident != MAC_MODEL_C660) &&
(macintosh_config->ident != MAC_MODEL_Q840)) {
via_alt_mapping = 1;
via1[vDirB] |= 0x40;
via1[vBufB] &= ~0x40;
} else {
via_alt_mapping = 0;
}
/*
* Now initialize VIA2. For RBV we just kill all interrupts;
* for a regular VIA we also reset the timers and stuff.
*/
via2[gIER] = 0x7F;
via2[gIFR] = 0x7F | rbv_clear;
if (!rbv_present) {
via2[vT1LL] = 0;
via2[vT1LH] = 0;
via2[vT1CL] = 0;
via2[vT1CH] = 0;
via2[vT2CL] = 0;
via2[vT2CH] = 0;
via2[vACR] &= ~0xC0; /* setup T1 timer with no PB7 output */
via2[vACR] &= ~0x03; /* disable port A & B latches */
}
/* Everything below this point is VIA2 only... */
if (rbv_present)
return;
/*
* Set vPCR for control line interrupts.
*
* CA1 (SLOTS IRQ), CB1 (ASC IRQ): negative edge trigger.
*
* Macs with ESP SCSI have a negative edge triggered SCSI interrupt.
* Testing reveals that PowerBooks do too. However, the SE/30
* schematic diagram shows an active high NCR5380 IRQ line.
*/
pr_debug("VIA2 vPCR is 0x%02X\n", via2[vPCR]);
if (macintosh_config->via_type == MAC_VIA_II) {
/* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, pos. edge */
via2[vPCR] = 0x66;
} else {
/* CA2 (SCSI DRQ), CB2 (SCSI IRQ): indep. input, neg. edge */
via2[vPCR] = 0x22;
}
}
/*
* Start the 100 Hz clock
*/
void __init via_init_clock(irq_handler_t func)
{
via1[vACR] |= 0x40;
via1[vT1LL] = MAC_CLOCK_LOW;
via1[vT1LH] = MAC_CLOCK_HIGH;
via1[vT1CL] = MAC_CLOCK_LOW;
via1[vT1CH] = MAC_CLOCK_HIGH;
if (request_irq(IRQ_MAC_TIMER_1, func, 0, "timer", func))
pr_err("Couldn't register %s interrupt\n", "timer");
}
/*
* Debugging dump, used in various places to see what's going on.
*/
void via_debug_dump(void)
{
printk(KERN_DEBUG "VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
(uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]);
printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
(uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]);
if (oss_present) {
printk(KERN_DEBUG "VIA2: <OSS>\n");
} else if (rbv_present) {
printk(KERN_DEBUG "VIA2: IFR = 0x%02X IER = 0x%02X\n",
(uint) via2[rIFR], (uint) via2[rIER]);
printk(KERN_DEBUG " SIFR = 0x%02X SIER = 0x%02X\n",
(uint) via2[rSIFR], (uint) via2[rSIER]);
} else {
printk(KERN_DEBUG "VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
(uint) via2[vDirA], (uint) via2[vDirB],
(uint) via2[vACR]);
printk(KERN_DEBUG " PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
(uint) via2[vPCR],
(uint) via2[vIFR], (uint) via2[vIER]);
}
}
/*
* This is always executed with interrupts disabled.
*
* TBI: get time offset between scheduling timer ticks
*/
unsigned long mac_gettimeoffset (void)
{
unsigned long ticks, offset = 0;
/* read VIA1 timer 2 current value */
ticks = via1[vT1CL] | (via1[vT1CH] << 8);
/* The probability of underflow is less than 2% */
if (ticks > MAC_CLOCK_TICK - MAC_CLOCK_TICK / 50)
/* Check for pending timer interrupt in VIA1 IFR */
if (via1[vIFR] & 0x40) offset = TICK_SIZE;
ticks = MAC_CLOCK_TICK - ticks;
ticks = ticks * 10000L / MAC_CLOCK_TICK;
return ticks + offset;
}
/*
* Flush the L2 cache on Macs that have it by flipping
* the system into 24-bit mode for an instant.
*/
void via_flush_cache(void)
{
via2[gBufB] &= ~VIA2B_vMode32;
via2[gBufB] |= VIA2B_vMode32;
}
/*
* Return the status of the L2 cache on a IIci
*/
int via_get_cache_disable(void)
{
/* Safeguard against being called accidentally */
if (!via2) {
printk(KERN_ERR "via_get_cache_disable called on a non-VIA machine!\n");
return 1;
}
return (int) via2[gBufB] & VIA2B_vCDis;
}
/*
* Initialize VIA2 for Nubus access
*/
void __init via_nubus_init(void)
{
/* unlock nubus transactions */
if ((macintosh_config->adb_type != MAC_ADB_PB1) &&
(macintosh_config->adb_type != MAC_ADB_PB2)) {
/* set the line to be an output on non-RBV machines */
if (!rbv_present)
via2[vDirB] |= 0x02;
/* this seems to be an ADB bit on PMU machines */
/* according to MkLinux. -- jmt */
via2[gBufB] |= 0x02;
}
/*
* Disable the slot interrupts. On some hardware that's not possible.
* On some hardware it's unclear what all of these I/O lines do.
*/
switch (macintosh_config->via_type) {
case MAC_VIA_II:
case MAC_VIA_QUADRA:
pr_debug("VIA2 vDirA is 0x%02X\n", via2[vDirA]);
break;
case MAC_VIA_IICI:
/* RBV. Disable all the slot interrupts. SIER works like IER. */
via2[rSIER] = 0x7F;
break;
}
}
void via_nubus_irq_startup(int irq)
{
int irq_idx = IRQ_IDX(irq);
switch (macintosh_config->via_type) {
case MAC_VIA_II:
case MAC_VIA_QUADRA:
/* Make the port A line an input. Probably redundant. */
if (macintosh_config->via_type == MAC_VIA_II) {
/* The top two bits are RAM size outputs. */
via2[vDirA] &= 0xC0 | ~(1 << irq_idx);
} else {
/* Allow NuBus slots 9 through F. */
via2[vDirA] &= 0x80 | ~(1 << irq_idx);
}
/* fall through */
case MAC_VIA_IICI:
via_irq_enable(irq);
break;
}
}
void via_nubus_irq_shutdown(int irq)
{
switch (macintosh_config->via_type) {
case MAC_VIA_II:
case MAC_VIA_QUADRA:
/* Ensure that the umbrella CA1 interrupt remains enabled. */
via_irq_enable(irq);
break;
case MAC_VIA_IICI:
via_irq_disable(irq);
break;
}
}
/*
* The generic VIA interrupt routines (shamelessly stolen from Alan Cox's
* via6522.c :-), disable/pending masks added.
*/
void via1_irq(unsigned int irq, struct irq_desc *desc)
{
int irq_num;
unsigned char irq_bit, events;
events = via1[vIFR] & via1[vIER] & 0x7F;
if (!events)
return;
irq_num = VIA1_SOURCE_BASE;
irq_bit = 1;
do {
if (events & irq_bit) {
via1[vIFR] = irq_bit;
generic_handle_irq(irq_num);
}
++irq_num;
irq_bit <<= 1;
} while (events >= irq_bit);
}
static void via2_irq(unsigned int irq, struct irq_desc *desc)
{
int irq_num;
unsigned char irq_bit, events;
events = via2[gIFR] & via2[gIER] & 0x7F;
if (!events)
return;
irq_num = VIA2_SOURCE_BASE;
irq_bit = 1;
do {
if (events & irq_bit) {
via2[gIFR] = irq_bit | rbv_clear;
generic_handle_irq(irq_num);
}
++irq_num;
irq_bit <<= 1;
} while (events >= irq_bit);
}
/*
* Dispatch Nubus interrupts. We are called as a secondary dispatch by the
* VIA2 dispatcher as a fast interrupt handler.
*/
void via_nubus_irq(unsigned int irq, struct irq_desc *desc)
{
int slot_irq;
unsigned char slot_bit, events;
events = ~via2[gBufA] & 0x7F;
if (rbv_present)
events &= via2[rSIER];
else
events &= ~via2[vDirA];
if (!events)
return;
do {
slot_irq = IRQ_NUBUS_F;
slot_bit = 0x40;
do {
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);