patch-2.4.22 linux-2.4.22/include/asm-arm/arch-at91rm9200/time.h

• Lines: 95
• Date: 2003-08-25 04:44:43.000000000 -0700
• Orig file: linux-2.4.21/include/asm-arm/arch-at91rm9200/time.h
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.21/include/asm-arm/arch-at91rm9200/time.h linux-2.4.22/include/asm-arm/arch-at91rm9200/time.h
@@ -0,0 +1,94 @@
+/*
+ * linux/include/asm-arm/arch-at91rm9200/time.h
+ *
+ *  Copyright (C) 2003 SAN People
+ *  Copyright (C) 2003 ATMEL
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef __ASM_ARCH_TIME_H
+#define __ASM_ARCH_TIME_H
+
+#include <asm/system.h>
+
+extern unsigned long (*gettimeoffset)(void);
+
+/*
+ * Returns number of microseconds since last timer interrupt.  Note that interrupts
+ * will have been disabled by do_gettimeofday()
+ *  'LATCH' is hwclock ticks (see CLOCK_TICK_RATE in timex.h) per jiffy.
+ *  'tick' is usecs per jiffy (linux/timex.h).
+ */
+static unsigned long at91rm9200_gettimeoffset(void)
+{
+	unsigned long elapsed;
+
+	elapsed = (AT91_SYS->ST_CRTR - AT91_SYS->ST_RTAR) & AT91C_ST_ALMV;
+
+	return (unsigned long)(elapsed * tick) / LATCH;
+}
+
+/*
+ * IRQ handler for the timer.
+ */
+static void at91rm9200_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+{
+	if (AT91_SYS->ST_SR & AT91C_ST_PITS) {	/* This is a shared interrupt */
+		do {
+			do_timer(regs);
+
+			AT91_SYS->ST_RTAR = (AT91_SYS->ST_RTAR + LATCH) & AT91C_ST_ALMV;
+
+		} while (((AT91_SYS->ST_CRTR - AT91_SYS->ST_RTAR) & AT91C_ST_ALMV) >= LATCH);
+
+		do_profile(regs);
+	}
+}
+
+/*
+ * Set up timer interrupt.
+ */
+static inline void setup_timer(void)
+{
+	/* Disable all timer interrupts */
+	AT91_SYS->ST_IDR = AT91C_ST_PITS | AT91C_ST_WDOVF | AT91C_ST_RTTINC | AT91C_ST_ALMS;
+	(void) AT91_SYS->ST_SR;		/* Clear any pending interrupts */
+
+	/*
+	 * Make IRQs happen for the system timer.
+	 */
+	timer_irq.handler = at91rm9200_timer_interrupt;
+	timer_irq.flags = SA_SHIRQ | SA_INTERRUPT;
+	setup_arm_irq(AT91C_ID_SYS, &timer_irq);
+	gettimeoffset = at91rm9200_gettimeoffset;
+
+	/* Set initial alarm to 0 */
+	AT91_SYS->ST_RTAR = 0;
+
+	/* Real time counter incremented every 30.51758 microseconds */
+	AT91_SYS->ST_RTMR = 1;
+
+	/* Set Period Interval timer */
+	AT91_SYS->ST_PIMR = LATCH;
+
+	/* Change the kernel's 'tick' value to 10009 usec. (the default is 10000) */
+	tick = (LATCH * 1000000) / CLOCK_TICK_RATE;
+
+	/* Enable Period Interval Timer interrupt */
+	AT91_SYS->ST_IER = AT91C_ST_PITS;
+}
+
+#endif