patch-2.4.22 linux-2.4.22/include/asm-arm/arch-riscstation/time.h

• Lines: 199
• Date: 2003-08-25 04:44:43.000000000 -0700
• Orig file: linux-2.4.21/include/asm-arm/arch-riscstation/time.h
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.21/include/asm-arm/arch-riscstation/time.h linux-2.4.22/include/asm-arm/arch-riscstation/time.h
@@ -0,0 +1,198 @@
+/*
+ *  linux/include/asm-arm/arch-rs/time.h
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * (c) 2002 Simtec Electronics / Ben Dooks
+ *
+ * Bits taken from linux/include/asm-arm/arch-rpc/time.h
+ *
+ * (c) 1996-2002 Russell King
+ *
+ * Bits taken from linux/include/asm-arm/arch-ebsa285/time.h
+ *
+ * Copyright (C) 1998 Russell King.
+ * Copyright (C) 1998 Phil Blundell
+*/
+
+#define RTC_PORT(x)    (0x70 + (x))
+#define RTC_ALWAYS_BCD (0)
+
+#include <linux/mc146818rtc.h>
+#include <asm/mach-types.h>
+
+extern void ioctime_init(void);
+
+/* timer interrut - update things like profiling information and our
+ * copy of the RTC's time
+*/
+
+static void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	do_timer(regs);
+	do_set_rtc();
+	do_profile(regs);
+}
+
+/* get_isa_cmos_time()
+ *
+ * get the time from the CMOS RTC
+ *
+ * from linux/include/asm-arm/arch-ebsa285/time.h
+*/
+
+static unsigned long get_isa_cmos_time(void)
+{
+	unsigned int year, mon, day, hour, min, sec;
+	int i;
+
+	// check to see if the RTC makes sense.....
+	if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0)
+		return mktime(1970, 1, 1, 0, 0, 0);
+
+	/* The Linux interpretation of the CMOS clock register contents:
+	 * When the Update-In-Progress (UIP) flag goes from 1 to 0, the
+	 * RTC registers show the second which has precisely just started.
+	 * Let's hope other operating systems interpret the RTC the same way.
+	 */
+	/* read RTC exactly on falling edge of update flag */
+	for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
+		if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
+			break;
+
+	for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
+		if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
+			break;
+
+	do { /* Isn't this overkill ? UIP above should guarantee consistency */
+		sec  = CMOS_READ(RTC_SECONDS);
+		min  = CMOS_READ(RTC_MINUTES);
+		hour = CMOS_READ(RTC_HOURS);
+		day  = CMOS_READ(RTC_DAY_OF_MONTH);
+		mon  = CMOS_READ(RTC_MONTH);
+		year = CMOS_READ(RTC_YEAR);
+	} while (sec != CMOS_READ(RTC_SECONDS));
+
+	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+		BCD_TO_BIN(sec);
+		BCD_TO_BIN(min);
+		BCD_TO_BIN(hour);
+		BCD_TO_BIN(day);
+		BCD_TO_BIN(mon);
+		BCD_TO_BIN(year);
+	}
+	if ((year += 1900) < 1970)
+		year += 100;
+	return mktime(year, mon, day, hour, min, sec);
+}
+
+/* set_isa_cmos_time()
+ *
+ * set the CMOS RTC time
+ *
+ * from linux/include/asm-arm/arch-ebsa285/time.h
+*/
+
+static int
+set_isa_cmos_time(void)
+{
+	int retval = 0;
+	int real_seconds, real_minutes, cmos_minutes;
+	unsigned char save_control, save_freq_select;
+	unsigned long nowtime = xtime.tv_sec;
+
+	save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
+	CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
+
+	save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
+	CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
+
+	cmos_minutes = CMOS_READ(RTC_MINUTES);
+	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+		BCD_TO_BIN(cmos_minutes);
+
+	/*
+	 * since we're only adjusting minutes and seconds,
+	 * don't interfere with hour overflow. This avoids
+	 * messing with unknown time zones but requires your
+	 * RTC not to be off by more than 15 minutes
+	 */
+	real_seconds = nowtime % 60;
+	real_minutes = nowtime / 60;
+	if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
+		real_minutes += 30;		/* correct for half hour time zone */
+	real_minutes %= 60;
+
+	if (abs(real_minutes - cmos_minutes) < 30) {
+		if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+			BIN_TO_BCD(real_seconds);
+			BIN_TO_BCD(real_minutes);
+		}
+		CMOS_WRITE(real_seconds,RTC_SECONDS);
+		CMOS_WRITE(real_minutes,RTC_MINUTES);
+	} else
+		retval = -1;
+
+	/* The following flags have to be released exactly in this order,
+	 * otherwise the DS12887 (popular MC146818A clone with integrated
+	 * battery and quartz) will not reset the oscillator and will not
+	 * update precisely 500 ms later. You won't find this mentioned in
+	 * the Dallas Semiconductor data sheets, but who believes data
+	 * sheets anyway ...                           -- Markus Kuhn
+	 */
+	CMOS_WRITE(save_control, RTC_CONTROL);
+	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
+
+	return retval;
+}
+
+
+/*
+ * Set up timer interrupt.
+ */
+static inline void setup_timer(void)
+{
+	int reg_b, reg_d;
+
+	ioctime_init();
+
+	/* ensure we have an RTC chip, and initialise it... */
+
+	reg_d = CMOS_READ(RTC_REG_D);
+
+	CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A);
+
+	/*
+	 * Set control reg B
+	 *   (24 hour mode, update enabled)
+	 */
+	reg_b = CMOS_READ(RTC_REG_B) & 0x7f;
+	reg_b |= 2;
+	CMOS_WRITE(reg_b, RTC_REG_B);
+
+	if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ &&
+	    CMOS_READ(RTC_REG_B) == reg_b) {
+
+		/*
+		 * We have a RTC.  Check the battery
+		 */
+		if ((reg_d & 0x80) == 0)
+			printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n");
+
+		printk("RTC: detected\n");
+
+		xtime.tv_sec = get_isa_cmos_time();
+		set_rtc = set_isa_cmos_time;
+	} else {
+		printk("RTC: Warning: No RTC detected\n");
+	}
+
+	/* ensure we have the IOC time interrupt setup */
+
+	timer_irq.handler = timer_interrupt;
+
+	setup_arm_irq(IRQ_TIMER, &timer_irq);
+}
+