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authorWolfgang Denk <wd@denx.de>2008-08-12 22:02:27 +0200
committerWolfgang Denk <wd@denx.de>2008-08-12 22:02:27 +0200
commit8641ff266ae6638da201747c239fd39ba34c4958 (patch)
tree0470bdb1e588449a9133ed62ac6b49d0213948e4 /cpu/arm926ejs/at91/timer.c
parent195ccfc5991d48764b2519941e3507f693851d5d (diff)
parent8ed2f5f950e2581214d20b011a8f27a6396d65d2 (diff)
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Merge branch 'master' of git://www.denx.de/git/u-boot-at91
Diffstat (limited to 'cpu/arm926ejs/at91/timer.c')
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diff --git a/cpu/arm926ejs/at91/timer.c b/cpu/arm926ejs/at91/timer.c
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+/*
+ * (C) Copyright 2007-2008
+ * Stelian Pop <stelian.pop@leadtechdesign.com>
+ * Lead Tech Design <www.leadtechdesign.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 <asm/arch/hardware.h>
+#include <asm/arch/at91_pit.h>
+#include <asm/arch/at91_pmc.h>
+#include <asm/arch/at91_rstc.h>
+#include <asm/arch/io.h>
+
+/*
+ * We're using the AT91CAP9/SAM9 PITC in 32 bit mode, by
+ * setting the 20 bit counter period to its maximum (0xfffff).
+ */
+#define TIMER_LOAD_VAL 0xfffff
+#define READ_RESET_TIMER at91_sys_read(AT91_PIT_PIVR)
+#define READ_TIMER at91_sys_read(AT91_PIT_PIIR)
+#define TIMER_FREQ (AT91C_MASTER_CLOCK << 4)
+#define TICKS_TO_USEC(ticks) ((ticks) / 6)
+
+ulong get_timer_masked(void);
+ulong resettime;
+
+/* nothing really to do with interrupts, just starts up a counter. */
+int timer_init(void)
+{
+ /*
+ * Enable PITC Clock
+ * The clock is already enabled for system controller in boot
+ */
+ at91_sys_write(AT91_PMC_PCER, 1 << AT91_ID_SYS);
+
+ /* Enable PITC */
+ at91_sys_write(AT91_PIT_MR, TIMER_LOAD_VAL | AT91_PIT_PITEN);
+
+ reset_timer_masked();
+
+ return 0;
+}
+
+/*
+ * timer without interrupts
+ */
+
+static inline ulong get_timer_raw(void)
+{
+ ulong now = READ_TIMER;
+
+ if (now >= resettime)
+ return now - resettime;
+ else
+ return 0xFFFFFFFFUL - (resettime - now) ;
+}
+
+void reset_timer_masked(void)
+{
+ resettime = READ_TIMER;
+}
+
+ulong get_timer_masked(void)
+{
+ return TICKS_TO_USEC(get_timer_raw());
+
+}
+
+void udelay_masked(unsigned long usec)
+{
+ ulong tmp;
+
+ tmp = get_timer(0);
+ while (get_timer(tmp) < usec) /* our timer works in usecs */
+ ; /* NOP */
+}
+
+void reset_timer(void)
+{
+ reset_timer_masked();
+}
+
+ulong get_timer(ulong base)
+{
+ ulong now = get_timer_masked();
+
+ if (now >= base)
+ return now - base;
+ else
+ return TICKS_TO_USEC(0xFFFFFFFFUL) - (base - now) ;
+}
+
+void udelay(unsigned long usec)
+{
+ udelay_masked(usec);
+}
+
+/*
+ * 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;
+}
+
+/*
+ * Reset the cpu by setting up the watchdog timer and let him time out.
+ */
+void reset_cpu(ulong ignored)
+{
+ /* this is the way Linux does it */
+ at91_sys_write(AT91_RSTC_CR, AT91_RSTC_KEY |
+ AT91_RSTC_PROCRST |
+ AT91_RSTC_PERRST);
+
+ while (1);
+ /* Never reached */
+}