patch-2.3.17 linux/arch/m68k/mac/via.c
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- Lines: 775
- Date:
Sat Sep 4 13:06:41 1999
- Orig file:
v2.3.16/linux/arch/m68k/mac/via.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -u --recursive --new-file v2.3.16/linux/arch/m68k/mac/via.c linux/arch/m68k/mac/via.c
@@ -0,0 +1,774 @@
+/*
+ * 6522 Versatile Interface Adapter (VIA)
+ *
+ * There are two of these on the Mac II. Some IRQ's 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
+ *
+ * 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 <asm/traps.h>
+#include <asm/bootinfo.h>
+#include <asm/macintosh.h>
+#include <asm/macints.h>
+#include <asm/machw.h>
+#include <asm/mac_via.h>
+#include <asm/mac_psc.h>
+
+volatile __u8 *via1, *via2;
+#if 0
+/* See note in mac_via.h about how this is possibly not useful */
+volatile long *via_memory_bogon=(long *)&via_memory_bogon;
+#endif
+int rbv_present,via_alt_mapping;
+__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
+ * _consistantly_ 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)
+
+static int nubus_active;
+
+void via_debug_dump(void);
+void via1_irq(int, void *, struct pt_regs *);
+void via2_irq(int, void *, struct pt_regs *);
+void via_nubus_irq(int, void *, struct pt_regs *);
+void via_irq_enable(int irq);
+void via_irq_disable(int irq);
+void via_irq_clear(int irq);
+
+extern void mac_bang(int, void *, struct pt_regs *);
+extern void mac_SCC_handler(int, void *, struct pt_regs *);
+extern int console_loglevel;
+extern int oss_present;
+
+/*
+ * 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("VIA1 at %p is a 6522 or clone\n", via1);
+
+ printk("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] &= 0x3F;
+
+ /*
+ * 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 1
+ /* Some machines support an alternate IRQ mapping that spreads */
+ /* Ethernet and Sound out to their own autolevel IRQs and moves */
+ /* VIA1 to level 6. A/UX uses this mapping and we do too. Note */
+ /* that the IIfx emulates this alternate mapping using the OSS. */
+
+ switch(macintosh_config->ident) {
+ case MAC_MODEL_C610:
+ case MAC_MODEL_Q610:
+ case MAC_MODEL_C650:
+ case MAC_MODEL_Q650:
+ case MAC_MODEL_Q700:
+ case MAC_MODEL_Q800:
+ case MAC_MODEL_Q900:
+ case MAC_MODEL_Q950:
+ via_alt_mapping = 1;
+ via1[vDirB] |= 0x40;
+ via1[vBufB] &= ~0x40;
+ break;
+ default:
+ via_alt_mapping = 0;
+ break;
+ }
+#else
+ /* The alernate IRQ mapping seems to just not work. Anyone with a */
+ /* supported machine is welcome to take a stab at fixing it. It */
+ /* _should_ work on the following Quadras: 610,650,700,800,900,950 */
+ /* - 1999-06-12 (jmt) */
+
+ via_alt_mapping = 0;
+#endif
+
+ /*
+ * 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] &= 0x3F;
+ }
+}
+
+/*
+ * Start the 100 Hz clock
+ */
+
+void __init via_init_clock(void (*func)(int, void *, struct pt_regs *))
+{
+ via1[vACR] |= 0x40;
+ via1[vT1LL] = MAC_CLOCK_LOW;
+ via1[vT1LH] = MAC_CLOCK_HIGH;
+ via1[vT1CL] = MAC_CLOCK_LOW;
+ via1[vT1CH] = MAC_CLOCK_HIGH;
+
+ request_irq(IRQ_MAC_TIMER_1, func, IRQ_FLG_LOCK, "timer", func);
+}
+
+/*
+ * Register the interrupt dispatchers for VIA or RBV machines only.
+ */
+
+void __init via_register_interrupts(void)
+{
+ if (via_alt_mapping) {
+ request_irq(IRQ_AUTO_1, via1_irq, IRQ_FLG_LOCK|IRQ_FLG_FAST,
+ "Software IRQ", (void *) via1);
+ request_irq(IRQ_AUTO_6, via1_irq, IRQ_FLG_LOCK|IRQ_FLG_FAST,
+ "VIA1 Dispatch", (void *) via1);
+ } else {
+ request_irq(IRQ_AUTO_1, via1_irq, IRQ_FLG_LOCK|IRQ_FLG_FAST,
+ "VIA1 Dispatch", (void *) via1);
+#if 0 /* interferes with serial on some machines */
+ if (!psc_present) {
+ request_irq(IRQ_AUTO_6, mac_bang, IRQ_FLG_LOCK,
+ "Off Switch", mac_bang);
+ }
+#endif
+ }
+ request_irq(IRQ_AUTO_2, via2_irq, IRQ_FLG_LOCK|IRQ_FLG_FAST,
+ "VIA2 Dispatch", (void *) via2);
+ if (!psc_present) {
+ request_irq(IRQ_AUTO_4, mac_SCC_handler, IRQ_FLG_LOCK,
+ "SCC Dispatch", mac_SCC_handler);
+ }
+ request_irq(IRQ_MAC_NUBUS, via_nubus_irq, IRQ_FLG_LOCK|IRQ_FLG_FAST,
+ "Nubus Dispatch", (void *) via2);
+}
+
+/*
+ * Debugging dump, used in various places to see what's going on.
+ */
+
+void via_debug_dump(void)
+{
+ printk("VIA1: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
+ (uint) via1[vDirA], (uint) via1[vDirB], (uint) via1[vACR]);
+ printk(" PCR = 0x%02X IFR = 0x%02X IER = 0x%02X\n",
+ (uint) via1[vPCR], (uint) via1[vIFR], (uint) via1[vIER]);
+ if (oss_present) {
+ printk("VIA2: <OSS>\n");
+ } else if (rbv_present) {
+ printk("VIA2: IFR = 0x%02X IER = 0x%02X\n",
+ (uint) via2[rIFR], (uint) via2[rIER]);
+ printk(" SIFR = 0x%02X SIER = 0x%02X\n",
+ (uint) via2[rSIFR], (uint) via2[rSIER]);
+ } else {
+ printk("VIA2: DDRA = 0x%02X DDRB = 0x%02X ACR = 0x%02X\n",
+ (uint) via2[vDirA], (uint) via2[vDirB],
+ (uint) via2[vACR]);
+ printk(" 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;
+}
+
+/*
+ * VIA-based power switch, for machines that support it.
+ */
+
+void via_poweroff(void)
+{
+ if (rbv_present) {
+ via2[rBufB] &= ~0x04;
+ } else {
+ /* Direction of vDirB is output */
+ via2[vDirB] |= 0x04;
+ /* Send a value of 0 on that line */
+ via2[vBufB] &= ~0x04;
+ /* Otherwise it prints "It is now.." then shuts off */
+ mdelay(1000);
+ }
+
+ /* We should never make it this far... */
+ printk ("It is now safe to switch off your machine.\n");
+ while(1);
+}
+
+/*
+ * Initialize VIA2 for Nubus access
+ */
+
+void __init via_nubus_init(void)
+{
+ nubus_active = 0;
+
+ /* unlock nubus transactions */
+
+ if (!rbv_present) {
+ /* set the line to be an output on non-RBV machines */
+ via2[vDirB] |= 0x02;
+ }
+ via2[gBufB] |= 0x02;
+
+ /* disable nubus slot interrupts. */
+ if (rbv_present) {
+ via2[rSIER] = 0x7F; /* like VIA; bit 7=clr,set */
+ } else {
+ via2[vBufA] = 0xFF; /* active low irqs, force high */
+ via2[vDirA] = 0xFF; /* ddr to output. */
+ }
+}
+
+/*
+ * The generic VIA interrupt routines (shamelessly stolen from Alan Cox's
+ * via6522.c :-), disable/pending masks added.
+ *
+ * The new interrupt architecture in macints.c takes care of a lot of the
+ * gruntwork for us, including tallying the interrupts and calling the
+ * handlers on the linked list. All we need to do here is basically generate
+ * the machspec interrupt number after clearing the interrupt.
+ */
+
+void via1_irq(int irq, void *dev_id, struct pt_regs *regs)
+{
+ int irq_bit, i;
+ unsigned char events, mask;
+
+ irq -= VEC_SPUR;
+
+ mask = via1[vIER] & 0x7F;
+ if (!(events = via1[vIFR] & mask)) return;
+
+ for (i = 0, irq_bit = 1 ; i < 7 ; i++, irq_bit <<= 1)
+ if (events & irq_bit) {
+ via1[vIER] = irq_bit;
+ mac_do_irq_list(VIA1_SOURCE_BASE + i, regs);
+ via1[vIFR] = irq_bit;
+ via1[vIER] = irq_bit | 0x80;
+ }
+
+ if (!oss_present) {
+ /* This (still) seems to be necessary to get IDE
+ working. However, if you enable VBL interrupts,
+ you're screwed... */
+ /* FIXME: should we check the SLOTIRQ bit before
+ pulling this stunt? */
+ /* No, it won't be set. that's why we're doing this. */
+ via_irq_disable(IRQ_MAC_NUBUS);
+ via_irq_clear(IRQ_MAC_NUBUS);
+ mac_do_irq_list(IRQ_MAC_NUBUS, regs);
+ via_irq_enable(IRQ_MAC_NUBUS);
+ }
+}
+
+void via2_irq(int irq, void *dev_id, struct pt_regs *regs)
+{
+ int irq_bit, i;
+ unsigned char events, mask;
+
+ irq -= VEC_SPUR;
+
+ mask = via2[gIER] & 0x7F;
+ if (!(events = via2[gIFR] & mask)) return;
+
+ for (i = 0, irq_bit = 1 ; i < 7 ; i++, irq_bit <<= 1)
+ if (events & irq_bit) {
+ via2[gIER] = irq_bit;
+ mac_do_irq_list(VIA2_SOURCE_BASE + i, regs);
+ via2[gIFR] = irq_bit | rbv_clear;
+ via2[gIER] = irq_bit | 0x80;
+ }
+}
+
+/*
+ * Dispatch Nubus interrupts. We are called as a secondary dispatch by the
+ * VIA2 dispatcher as a fast interrupt handler.
+ */
+
+void via_nubus_irq(int irq, void *dev_id, struct pt_regs *regs)
+{
+ int irq_bit, i;
+ unsigned char events;
+
+ if (!(events = ~via2[gBufA] & nubus_active)) return;
+
+ for (i = 0, irq_bit = 1 ; i < 7 ; i++, irq_bit <<= 1) {
+ if (events & irq_bit) {
+ via_irq_disable(NUBUS_SOURCE_BASE + i);
+ mac_do_irq_list(NUBUS_SOURCE_BASE + i, regs);
+ via_irq_enable(NUBUS_SOURCE_BASE + i);
+ }
+ }
+}
+
+void via_irq_enable(int irq) {
+ int irq_src = IRQ_SRC(irq);
+ int irq_idx = IRQ_IDX(irq);
+ int irq_bit = 1 << irq_idx;
+
+#ifdef DEBUG_IRQUSE
+ printk("via_irq_enable(%d)\n", irq);
+#endif
+
+ if (irq_src == 1) {
+ via1[vIER] = irq_bit | 0x80;
+ } else if (irq_src == 2) {
+ /*
+ * Set vPCR for SCSI interrupts (but not on RBV)
+ */
+ if ((irq_idx == 0) && !rbv_present) {
+ if (macintosh_config->scsi_type == MAC_SCSI_OLD) {
+ /* CB2 (IRQ) indep. input, positive edge */
+ /* CA2 (DRQ) indep. input, positive edge */
+ via2[vPCR] = 0x66;
+ } else {
+ /* CB2 (IRQ) indep. input, negative edge */
+ /* CA2 (DRQ) indep. input, negative edge */
+ via2[vPCR] = 0x22;
+ }
+ }
+ via2[gIER] = irq_bit | 0x80;
+ } else if (irq_src == 7) {
+ if (rbv_present) {
+ /* enable the slot interrupt. SIER works like IER. */
+ via2[rSIER] = IER_SET_BIT(irq_idx);
+ } else {
+ /* Make sure the bit is an input, to enable the irq */
+ via2[vDirA] &= ~irq_bit;
+ }
+ nubus_active |= irq_bit;
+ }
+}
+
+void via_irq_disable(int irq) {
+ int irq_src = IRQ_SRC(irq);
+ int irq_idx = IRQ_IDX(irq);
+ int irq_bit = 1 << irq_idx;
+
+#ifdef DEBUG_IRQUSE
+ printk("via_irq_disable(%d)\n", irq);
+#endif
+
+ if (irq_src == 1) {
+ via1[vIER] = irq_bit;
+ } else if (irq_src == 2) {
+ via2[gIER] = irq_bit;
+ } else if (irq_src == 7) {
+ if (rbv_present) {
+ /* disable the slot interrupt. SIER works like IER. */
+ via2[rSIER] = IER_CLR_BIT(irq_idx);
+ } else {
+ /* disable the nubus irq by changing dir to output */
+ via2[vDirA] |= irq_bit;
+ }
+ nubus_active &= ~irq_bit;
+ }
+}
+
+void via_irq_clear(int irq) {
+ int irq_src = IRQ_SRC(irq);
+ int irq_idx = IRQ_IDX(irq);
+ int irq_bit = 1 << irq_idx;
+
+ if (irq_src == 1) {
+ via1[vIFR] = irq_bit;
+ } else if (irq_src == 2) {
+ via2[gIFR] = irq_bit | rbv_clear;
+ } else if (irq_src == 7) {
+ /* FIXME: hmm.. */
+ }
+}
+
+/*
+ * Returns nonzero if an interrupt is pending on the given
+ * VIA/IRQ combination.
+ */
+
+int via_irq_pending(int irq)
+{
+ int irq_src = IRQ_SRC(irq);
+ int irq_idx = IRQ_IDX(irq);
+ int irq_bit = 1 << irq_idx;
+
+ if (irq_src == 1) {
+ return via1[vIFR] & irq_bit;
+ } else if (irq_src == 2) {
+ return via2[gIFR] & irq_bit;
+ } else if (irq_src == 7) {
+ return ~via2[gBufA] & irq_bit;
+ }
+ return 0;
+}
+
+void via_scsi_clear(void)
+{
+ volatile unsigned char deep_magic;
+
+#ifdef DEBUG_IRQUSE
+ printk("via_scsi_clear()\n");
+#endif
+
+ /* We handle this in oss.c , but this gets called in mac_scsinew.c */
+ if(oss_present) return;
+
+ if (rbv_present) {
+ via2[rIFR] = (1<<3) | (1<<0) | rbv_clear;
+ deep_magic = via2[rBufB];
+ } else {
+ deep_magic = via2[vBufB];
+ }
+ mac_enable_irq(IRQ_MAC_SCSI);
+}
+
+/*
+ * PRAM/RTC access routines
+ *
+ * Must be called with interrupts disabled and
+ * the RTC should be enabled.
+ */
+
+static __u8 via_pram_readbyte(void)
+{
+ int i,reg;
+ __u8 data;
+
+ reg = via1[vBufB] & ~VIA1B_vRTCClk;
+
+ /* Set the RTC data line to be an input. */
+
+ via1[vDirB] &= ~VIA1B_vRTCData;
+
+ /* The bits of the byte come out in MSB order */
+
+ data = 0;
+ for (i = 0 ; i < 8 ; i++) {
+ via1[vBufB] = reg;
+ via1[vBufB] = reg | VIA1B_vRTCClk;
+ data = (data << 1) | (via1[vBufB] & VIA1B_vRTCData);
+ }
+
+ /* Return RTC data line to output state */
+
+ via1[vDirB] |= VIA1B_vRTCData;
+
+ return data;
+}
+
+static void via_pram_writebyte(__u8 data)
+{
+ int i,reg,bit;
+
+ reg = via1[vBufB] & ~(VIA1B_vRTCClk | VIA1B_vRTCData);
+
+ /* The bits of the byte go in in MSB order */
+
+ for (i = 0 ; i < 8 ; i++) {
+ bit = data & 0x80? 1 : 0;
+ data <<= 1;
+ via1[vBufB] = reg | bit;
+ via1[vBufB] = reg | bit | VIA1B_vRTCClk;
+ }
+}
+
+/*
+ * Execute a PRAM/RTC command. For read commands
+ * data should point to a one-byte buffer for the
+ * resulting data. For write commands it should point
+ * to the data byte to for the command.
+ *
+ * This function disables all interrupts while running.
+ */
+
+void via_pram_command(int command, __u8 *data)
+{
+ unsigned long cpu_flags;
+ int is_read;
+
+ save_flags(cpu_flags);
+ cli();
+
+ /* Enable the RTC and make sure the strobe line is high */
+
+ via1[vBufB] = (via1[vBufB] | VIA1B_vRTCClk) & ~VIA1B_vRTCEnb;
+
+ if (command & 0xFF00) { /* extended (two-byte) command */
+ via_pram_writebyte((command & 0xFF00) >> 8);
+ via_pram_writebyte(command & 0xFF);
+ is_read = command & 0x8000;
+ } else { /* one-byte command */
+ via_pram_writebyte(command);
+ is_read = command & 0x80;
+ }
+ if (is_read) {
+ *data = via_pram_readbyte();
+ } else {
+ via_pram_writebyte(*data);
+ }
+
+ /* All done, disable the RTC */
+
+ via1[vBufB] |= VIA1B_vRTCEnb;
+
+ restore_flags(cpu_flags);
+}
+
+/*
+ * Return the current time in seconds since January 1, 1904.
+ *
+ * This only works on machines with the VIA-based PRAM/RTC, which
+ * is basically any machine with Mac II-style ADB.
+ */
+
+__u32 via_read_time(void)
+{
+ union {
+ __u8 cdata[4];
+ __u32 idata;
+ } result, last_result;
+ int ct;
+
+ /*
+ * The NetBSD guys say to loop until you get the same reading
+ * twice in a row.
+ */
+
+ ct = 0;
+ do {
+ if (++ct > 10) {
+ printk("via_read_time: couldn't get valid time, "
+ "last read = 0x%08X and 0x%08X\n", last_result.idata,
+ result.idata);
+ break;
+ }
+
+ last_result.idata = result.idata;
+ result.idata = 0;
+
+ via_pram_command(0x81, &result.cdata[3]);
+ via_pram_command(0x85, &result.cdata[2]);
+ via_pram_command(0x89, &result.cdata[1]);
+ via_pram_command(0x8D, &result.cdata[0]);
+ } while (result.idata != last_result.idata);
+
+ return result.idata;
+}
+
+/*
+ * Set the current time to a number of seconds since January 1, 1904.
+ *
+ * This only works on machines with the VIA-based PRAM/RTC, which
+ * is basically any machine with Mac II-style ADB.
+ */
+
+void via_write_time(__u32 time)
+{
+ union {
+ __u8 cdata[4];
+ __u32 idata;
+ } data;
+ __u8 temp;
+
+ /* Clear the write protect bit */
+
+ temp = 0x55;
+ via_pram_command(0x35, &temp);
+
+ data.idata = time;
+ via_pram_command(0x01, &data.cdata[3]);
+ via_pram_command(0x05, &data.cdata[2]);
+ via_pram_command(0x09, &data.cdata[1]);
+ via_pram_command(0x0D, &data.cdata[0]);
+
+ /* Set the write protect bit */
+
+ temp = 0xD5;
+ via_pram_command(0x35, &temp);
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)