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