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-rw-r--r--arch/m68k/mac/via.c278
1 files changed, 155 insertions, 123 deletions
diff --git a/arch/m68k/mac/via.c b/arch/m68k/mac/via.c
index 5d1458bb871b..9cb813eda4fd 100644
--- a/arch/m68k/mac/via.c
+++ b/arch/m68k/mac/via.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* 6522 Versatile Interface Adapter (VIA)
*
@@ -22,6 +23,7 @@
*
*/
+#include <linux/clocksource.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
@@ -30,13 +32,14 @@
#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>
+#include "mac.h"
+
volatile __u8 *via1, *via2;
int rbv_present;
int via_alt_mapping;
@@ -55,21 +58,11 @@ static __u8 rbv_clear;
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
+ * We used to fake it by configuring the relevant 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,
@@ -107,6 +100,7 @@ static int gIER,gIFR,gBufA,gBufB;
static u8 nubus_disabled;
void via_debug_dump(void);
+static void via_nubus_init(void);
/*
* Initialize the VIAs
@@ -114,29 +108,25 @@ void via_debug_dump(void);
* 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) {
+ via1 = (void *)VIA1_BASE;
+ pr_debug("VIA1 detected at %p\n", via1);
+
+ if (oss_present) {
+ via2 = NULL;
+ rbv_present = 0;
+ } else {
+ 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;
- }
+ via2 = (void *)RBV_BASE;
+ pr_debug("VIA2 (RBV) detected at %p\n", via2);
+ rbv_present = 1;
if (macintosh_config->ident == MAC_MODEL_LCIII) {
rbv_clear = 0x00;
} else {
@@ -155,29 +145,19 @@ void __init via_init(void)
case MAC_VIA_QUADRA:
case MAC_VIA_II:
- via1 = (void *) VIA1_BASE;
via2 = (void *) VIA2_BASE;
+ pr_debug("VIA2 detected at %p\n", via2);
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
@@ -191,8 +171,6 @@ void __init via_init(void)
via1[vIER] = 0x7F;
via1[vIFR] = 0x7F;
- via1[vT1LL] = 0;
- via1[vT1LH] = 0;
via1[vT1CL] = 0;
via1[vT1CH] = 0;
via1[vT2CL] = 0;
@@ -202,7 +180,6 @@ void __init via_init(void)
/*
* SE/30: disable video IRQ
- * XXX: testing for SE/30 VBL
*/
if (macintosh_config->ident == MAC_MODEL_SE30) {
@@ -210,13 +187,18 @@ void __init via_init(void)
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);
+ switch (macintosh_config->adb_type) {
+ case MAC_ADB_IOP:
+ case MAC_ADB_II:
+ case MAC_ADB_PB1:
+ /*
+ * 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;
+ break;
+ }
/* Everything below this point is VIA2/RBV only... */
@@ -243,8 +225,6 @@ void __init via_init(void)
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;
@@ -253,6 +233,8 @@ void __init via_init(void)
via2[vACR] &= ~0x03; /* disable port A & B latches */
}
+ via_nubus_init();
+
/* Everything below this point is VIA2 only... */
if (rbv_present)
@@ -279,22 +261,6 @@ void __init via_init(void)
}
/*
- * 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.
*/
@@ -304,9 +270,9 @@ void via_debug_dump(void)
(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) {
+ if (!via2)
+ return;
+ 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",
@@ -322,59 +288,25 @@ void via_debug_dump(void)
}
/*
- * This is always executed with interrupts disabled.
- *
- * TBI: get time offset between scheduling timer ticks
- */
-
-u32 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) * 1000;
-}
-
-/*
* 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)
+void via_l2_flush(int writeback)
{
+ unsigned long flags;
+
+ local_irq_save(flags);
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;
+ local_irq_restore(flags);
}
/*
* Initialize VIA2 for Nubus access
*/
-void __init via_nubus_init(void)
+static void __init via_nubus_init(void)
{
/* unlock nubus transactions */
@@ -421,7 +353,7 @@ void via_nubus_irq_startup(int irq)
/* Allow NuBus slots 9 through F. */
via2[vDirA] &= 0x80 | ~(1 << irq_idx);
}
- /* fall through */
+ fallthrough;
case MAC_VIA_IICI:
via_irq_enable(irq);
break;
@@ -447,7 +379,9 @@ void via_nubus_irq_shutdown(int irq)
* via6522.c :-), disable/pending masks added.
*/
-void via1_irq(unsigned int irq, struct irq_desc *desc)
+#define VIA_TIMER_1_INT BIT(6)
+
+void via1_irq(struct irq_desc *desc)
{
int irq_num;
unsigned char irq_bit, events;
@@ -456,6 +390,21 @@ void via1_irq(unsigned int irq, struct irq_desc *desc)
if (!events)
return;
+ irq_num = IRQ_MAC_TIMER_1;
+ irq_bit = VIA_TIMER_1_INT;
+ if (events & irq_bit) {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ via1[vIFR] = irq_bit;
+ generic_handle_irq(irq_num);
+ local_irq_restore(flags);
+
+ events &= ~irq_bit;
+ if (!events)
+ return;
+ }
+
irq_num = VIA1_SOURCE_BASE;
irq_bit = 1;
do {
@@ -468,7 +417,7 @@ void via1_irq(unsigned int irq, struct irq_desc *desc)
} while (events >= irq_bit);
}
-static void via2_irq(unsigned int irq, struct irq_desc *desc)
+static void via2_irq(struct irq_desc *desc)
{
int irq_num;
unsigned char irq_bit, events;
@@ -494,7 +443,7 @@ static void via2_irq(unsigned int irq, struct irq_desc *desc)
* VIA2 dispatcher as a fast interrupt handler.
*/
-void via_nubus_irq(unsigned int irq, struct irq_desc *desc)
+static void via_nubus_irq(struct irq_desc *desc)
{
int slot_irq;
unsigned char slot_bit, events;
@@ -551,10 +500,6 @@ 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) {
@@ -583,10 +528,6 @@ 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) {
@@ -620,3 +561,94 @@ 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.
+ *
+ * The VIA timer counter observably decrements to 0xFFFF before the
+ * counter reload interrupt gets raised. That complicates things a bit.
+ *
+ * State | vT1CH | VIA_TIMER_1_INT | inference drawn
+ * ------+------------+-----------------+-----------------------------
+ * i | FE thru 00 | false | counter is decrementing
+ * ii | FF | false | counter wrapped
+ * iii | FF | true | wrapped, interrupt raised
+ * iv | FF | false | wrapped, interrupt handled
+ * v | FE thru 00 | true | wrapped, interrupt unhandled
+ *
+ * State iv is never observed because handling the interrupt involves
+ * a 6522 register access and every access consumes a "phi 2" clock
+ * cycle. So 0xFF implies either state ii or state iii, depending on
+ * the value of the VIA_TIMER_1_INT bit.
+ */
+
+ 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;
+}
generated by cgit (git 2.34.1) at 2025-12-25 17:20:51 +0000