patch-2.3.43 linux/arch/arm/kernel/time-acorn.c

• Lines: 72
• Date: Sun Feb 6 17:45:25 2000
• Orig file: v2.3.42/linux/arch/arm/kernel/time-acorn.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.42/linux/arch/arm/kernel/time-acorn.c linux/arch/arm/kernel/time-acorn.c
@@ -0,0 +1,71 @@
+/*
+ * linux/arch/arm/kernel/time-acorn.c
+ *
+ * Copyright (c) 1996-2000 Russell King.
+ *
+ * Changelog:
+ *  24-Sep-1996	RMK	Created
+ *  10-Oct-1996	RMK	Brought up to date with arch-sa110eval
+ *  04-Dec-1997	RMK	Updated for new arch/arm/time.c
+ */
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+
+#include <asm/hardware.h>
+#include <asm/io.h>
+#include <asm/ioc.h>
+#include <asm/irq.h>
+
+extern unsigned long (*gettimeoffset)(void);
+
+static unsigned long ioctime_gettimeoffset(void)
+{
+	unsigned int count1, count2, status1, status2;
+	unsigned long offset = 0;
+
+	status1 = inb(IOC_IRQREQA);
+	barrier ();
+	outb (0, IOC_T0LATCH);
+	barrier ();
+	count1 = inb(IOC_T0CNTL) | (inb(IOC_T0CNTH) << 8);
+	barrier ();
+	status2 = inb(IOC_IRQREQA);
+	barrier ();
+	outb (0, IOC_T0LATCH);
+	barrier ();
+	count2 = inb(IOC_T0CNTL) | (inb(IOC_T0CNTH) << 8);
+
+	if (count2 < count1) {
+		/*
+		 * This means that we haven't just had an interrupt
+		 * while reading into status2.
+		 */
+		if (status2 & (1 << 5))
+			offset = tick;
+		count1 = count2;
+	} else if (count2 > count1) {
+		/*
+		 * We have just had another interrupt while reading
+		 * status2.
+		 */
+		offset += tick;
+		count1 = count2;
+	}
+
+	count1 = LATCH - count1;
+	/*
+	 * count1 = number of clock ticks since last interrupt
+	 */
+	offset += count1 * tick / LATCH;
+	return offset;
+}
+
+void __init ioctime_init(void)
+{
+	outb(LATCH & 255, IOC_T0LTCHL);
+	outb(LATCH >> 8, IOC_T0LTCHH);
+	outb(0, IOC_T0GO);
+
+	gettimeoffset = ioctime_gettimeoffset;
+}