1 files changed, 115 insertions, 0 deletions
diff --git a/arch/m68k/hp300/time.c b/arch/m68k/hp300/time.c
new file mode 100644
index 000000000..1d1b7b3b5
--- /dev/null
+++ b/arch/m68k/hp300/time.c
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  linux/arch/m68k/hp300/time.c
+ *
+ *  Copyright (C) 1998 Philip Blundell <philb@gnu.org>
+ *
+ *  This file contains the HP300-specific time handling code.
+ */
+
+#include <asm/ptrace.h>
+#include <linux/clocksource.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/kernel_stat.h>
+#include <linux/interrupt.h>
+#include <asm/machdep.h>
+#include <asm/irq.h>
+#include <asm/io.h>
+#include <asm/traps.h>
+#include <asm/blinken.h>
+
+static u64 hp300_read_clk(struct clocksource *cs);
+
+static struct clocksource hp300_clk = {
+	.name   = "timer",
+	.rating = 250,
+	.read   = hp300_read_clk,
+	.mask   = CLOCKSOURCE_MASK(32),
+	.flags  = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+static u32 clk_total, clk_offset;
+
+/* Clock hardware definitions */
+
+#define CLOCKBASE	0xf05f8000
+
+#define	CLKCR1		0x1
+#define	CLKCR2		0x3
+#define	CLKCR3		CLKCR1
+#define	CLKSR		CLKCR2
+#define	CLKMSB1		0x5
+#define	CLKLSB1		0x7
+#define	CLKMSB2		0x9
+#define	CLKMSB3		0xD
+
+#define	CLKSR_INT1	BIT(0)
+
+/* This is for machines which generate the exact clock. */
+
+#define HP300_TIMER_CLOCK_FREQ 250000
+#define HP300_TIMER_CYCLES     (HP300_TIMER_CLOCK_FREQ / HZ)
+#define INTVAL                 (HP300_TIMER_CYCLES - 1)
+
+static irqreturn_t hp300_tick(int irq, void *dev_id)
+{
+	unsigned long flags;
+	unsigned long tmp;
+
+	local_irq_save(flags);
+	in_8(CLOCKBASE + CLKSR);
+	asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
+	clk_total += INTVAL;
+	clk_offset = 0;
+	legacy_timer_tick(1);
+	timer_heartbeat();
+	local_irq_restore(flags);
+
+	/* Turn off the network and SCSI leds */
+	blinken_leds(0, 0xe0);
+	return IRQ_HANDLED;
+}
+
+static u64 hp300_read_clk(struct clocksource *cs)
+{
+	unsigned long flags;
+	unsigned char lsb, msb, msb_new;
+	u32 ticks;
+
+	local_irq_save(flags);
+	/* Read current timer 1 value */
+	msb = in_8(CLOCKBASE + CLKMSB1);
+again:
+	if ((in_8(CLOCKBASE + CLKSR) & CLKSR_INT1) && msb > 0)
+		clk_offset = INTVAL;
+	lsb = in_8(CLOCKBASE + CLKLSB1);
+	msb_new = in_8(CLOCKBASE + CLKMSB1);
+	if (msb_new != msb) {
+		msb = msb_new;
+		goto again;
+	}
+
+	ticks = INTVAL - ((msb << 8) | lsb);
+	ticks += clk_offset + clk_total;
+	local_irq_restore(flags);
+
+	return ticks;
+}
+
+void __init hp300_sched_init(void)
+{
+  out_8(CLOCKBASE + CLKCR2, 0x1);		/* select CR1 */
+  out_8(CLOCKBASE + CLKCR1, 0x1);		/* reset */
+
+  asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));
+
+  if (request_irq(IRQ_AUTO_6, hp300_tick, IRQF_TIMER, "timer tick", NULL))
+    pr_err("Couldn't register timer interrupt\n");
+
+  out_8(CLOCKBASE + CLKCR2, 0x1);		/* select CR1 */
+  out_8(CLOCKBASE + CLKCR1, 0x40);		/* enable irq */
+
+  clocksource_register_hz(&hp300_clk, HP300_TIMER_CLOCK_FREQ);
+}