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authorMarkus Klotzbuecher <mk@denx.de>2006-03-24 15:43:16 +0100
committerMarkus Klotzbücher <mk@pollux.denx.de>2006-03-24 15:43:16 +0100
commit2770bcb21c82835a5351176e5b2a9221d7fc8ef9 (patch)
tree78edf9afc584e1a76d219bd64d260224a84f0d10 /cpu/arm926ejs/versatile/timer.c
parent0b953ffc653fc5ab3d3fa47abf0dd9b8bd0703f5 (diff)
parent05d8dce9d07cf4073ea15fbc448c1ce22b6baf0f (diff)
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Merge with http://www.denx.de/git/u-boot.git
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+/*
+ * (C) Copyright 2003
+ * Texas Instruments <www.ti.com>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger@sysgo.de>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Alex Zuepke <azu@sysgo.de>
+ *
+ * (C) Copyright 2002-2004
+ * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
+ *
+ * (C) Copyright 2004
+ * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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
+ */
+
+#include <common.h>
+#include <arm926ejs.h>
+
+#define TIMER_LOAD_VAL 0xffffffff
+
+/* macro to read the 32 bit timer */
+#define READ_TIMER (*(volatile ulong *)(CFG_TIMERBASE+4))
+
+static ulong timestamp;
+static ulong lastdec;
+
+/* nothing really to do with interrupts, just starts up a counter. */
+int timer_init (void)
+{
+ *(volatile ulong *)(CFG_TIMERBASE + 0) = CFG_TIMER_RELOAD; /* TimerLoad */
+ *(volatile ulong *)(CFG_TIMERBASE + 4) = CFG_TIMER_RELOAD; /* TimerValue */
+ *(volatile ulong *)(CFG_TIMERBASE + 8) = 0x8C;
+
+ /* init the timestamp and lastdec value */
+ reset_timer_masked();
+
+ return 0;
+}
+
+/*
+ * timer without interrupts
+ */
+
+void reset_timer (void)
+{
+ reset_timer_masked ();
+}
+
+ulong get_timer (ulong base)
+{
+ return get_timer_masked () - base;
+}
+
+void set_timer (ulong t)
+{
+ timestamp = t;
+}
+
+/* delay x useconds AND perserve advance timstamp value */
+void udelay (unsigned long usec)
+{
+ ulong tmo, tmp;
+
+ if(usec >= 1000){ /* if "big" number, spread normalization to seconds */
+ tmo = usec / 1000; /* start to normalize for usec to ticks per sec */
+ tmo *= CFG_HZ; /* find number of "ticks" to wait to achieve target */
+ tmo /= 1000; /* finish normalize. */
+ }else{ /* else small number, don't kill it prior to HZ multiply */
+ tmo = usec * CFG_HZ;
+ tmo /= (1000*1000);
+ }
+
+ tmp = get_timer (0); /* get current timestamp */
+ if( (tmo + tmp + 1) < tmp ) /* if setting this fordward will roll time stamp */
+ reset_timer_masked (); /* reset "advancing" timestamp to 0, set lastdec value */
+ else
+ tmo += tmp; /* else, set advancing stamp wake up time */
+
+ while (get_timer_masked () < tmo)/* loop till event */
+ /*NOP*/;
+}
+
+void reset_timer_masked (void)
+{
+ /* reset time */
+ lastdec = READ_TIMER; /* capure current decrementer value time */
+ timestamp = 0; /* start "advancing" time stamp from 0 */
+}
+
+ulong get_timer_masked (void)
+{
+ ulong now = READ_TIMER; /* current tick value */
+
+ if (lastdec >= now) { /* normal mode (non roll) */
+ /* normal mode */
+ timestamp += lastdec - now; /* move stamp fordward with absoulte diff ticks */
+ } else { /* we have overflow of the count down timer */
+ /* nts = ts + ld + (TLV - now)
+ * ts=old stamp, ld=time that passed before passing through -1
+ * (TLV-now) amount of time after passing though -1
+ * nts = new "advancing time stamp"...it could also roll and cause problems.
+ */
+ timestamp += lastdec + TIMER_LOAD_VAL - now;
+ }
+ lastdec = now;
+
+ return timestamp;
+}
+
+/* waits specified delay value and resets timestamp */
+void udelay_masked (unsigned long usec)
+{
+ ulong tmo;
+ ulong endtime;
+ signed long diff;
+
+ if (usec >= 1000) { /* if "big" number, spread normalization to seconds */
+ tmo = usec / 1000; /* start to normalize for usec to ticks per sec */
+ tmo *= CFG_HZ; /* find number of "ticks" to wait to achieve target */
+ tmo /= 1000; /* finish normalize. */
+ } else { /* else small number, don't kill it prior to HZ multiply */
+ tmo = usec * CFG_HZ;
+ tmo /= (1000*1000);
+ }
+
+ endtime = get_timer_masked () + tmo;
+
+ do {
+ ulong now = get_timer_masked ();
+ diff = endtime - now;
+ } while (diff >= 0);
+}
+
+/*
+ * This function is derived from PowerPC code (read timebase as long long).
+ * On ARM it just returns the timer value.
+ */
+unsigned long long get_ticks(void)
+{
+ return get_timer(0);
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+ulong get_tbclk (void)
+{
+ ulong tbclk;
+
+ tbclk = CFG_HZ;
+ return tbclk;
+}