patch-2.4.10 linux/arch/sh/kernel/rtc-aica.c

• Lines: 71
• Date: Sat Sep 8 12:29:09 2001
• Orig file: v2.4.9/linux/arch/sh/kernel/rtc-aica.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.9/linux/arch/sh/kernel/rtc-aica.c linux/arch/sh/kernel/rtc-aica.c
@@ -0,0 +1,70 @@
+/* arch/sh/kernel/rtc-aica.c
+ *
+ * Dreamcast AICA RTC routines.
+ *
+ * Copyright (c) 2001 M. R. Brown <mrbrown@0xd6.org>
+ *
+ * Released under the terms of the GNU GPL v2.0.
+ *
+ */
+
+#include <linux/time.h>
+
+#include <asm/io.h>
+
+/* The AICA RTC has an Epoch of 1/1/1950, so we must subtract 20 years (in
+   seconds to get the standard Unix Epoch when getting the time, and add 20
+   years when setting the time. */
+#define TWENTY_YEARS ((20 * 365LU + 5) * 86400)
+
+/* The AICA RTC is represented by a 32-bit seconds counter stored in 2 16-bit
+   registers.*/
+#define AICA_RTC_SECS_H		0xa0710000
+#define AICA_RTC_SECS_L		0xa0710004
+
+/**
+ * aica_rtc_gettimeofday - Get the time from the AICA RTC
+ * @tv: pointer to resulting timeval
+ *
+ * Grabs the current RTC seconds counter and adjusts it to the Unix Epoch.
+ */
+void aica_rtc_gettimeofday(struct timeval *tv) {
+	unsigned long val1, val2;
+
+	do {
+		val1 = ((ctrl_inl(AICA_RTC_SECS_H) & 0xffff) << 16) |
+			(ctrl_inl(AICA_RTC_SECS_L) & 0xffff);
+
+		val2 = ((ctrl_inl(AICA_RTC_SECS_H) & 0xffff) << 16) |
+			(ctrl_inl(AICA_RTC_SECS_L) & 0xffff);
+	} while (val1 != val2);
+
+	tv->tv_sec = val1 - TWENTY_YEARS;
+
+	/* Can't get microseconds with just a seconds counter. */
+	tv->tv_usec = 0;
+}
+
+/**
+ * aica_rtc_settimeofday - Set the AICA RTC to the current time
+ * @tv: contains the timeval to set
+ *
+ * Adjusts the given @tv to the AICA Epoch and sets the RTC seconds counter.
+ */
+int aica_rtc_settimeofday(const struct timeval *tv) {
+	unsigned long val1, val2;
+	unsigned long secs = tv->tv_sec + TWENTY_YEARS;
+
+	do {
+		ctrl_outl((secs & 0xffff0000) >> 16, AICA_RTC_SECS_H);
+		ctrl_outl((secs & 0xffff), AICA_RTC_SECS_L);
+
+		val1 = ((ctrl_inl(AICA_RTC_SECS_H) & 0xffff) << 16) |
+			(ctrl_inl(AICA_RTC_SECS_L) & 0xffff);
+
+		val2 = ((ctrl_inl(AICA_RTC_SECS_H) & 0xffff) << 16) |
+			(ctrl_inl(AICA_RTC_SECS_L) & 0xffff);
+	} while (val1 != val2);
+
+	return 0;
+}