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-rw-r--r--arch/arm/cpu/armv7/zynq/timer.c179
1 files changed, 179 insertions, 0 deletions
diff --git a/arch/arm/cpu/armv7/zynq/timer.c b/arch/arm/cpu/armv7/zynq/timer.c
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+++ b/arch/arm/cpu/armv7/zynq/timer.c
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+/*
+ * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
+ * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
+ *
+ * (C) Copyright 2008
+ * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
+ *
+ * (C) Copyright 2004
+ * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
+ *
+ * (C) Copyright 2002-2004
+ * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
+ *
+ * (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>
+ *
+ * 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 <div64.h>
+#include <asm/io.h>
+#include <asm/arch/hardware.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct scu_timer {
+ u32 load; /* Timer Load Register */
+ u32 counter; /* Timer Counter Register */
+ u32 control; /* Timer Control Register */
+};
+
+static struct scu_timer *timer_base =
+ (struct scu_timer *)ZYNQ_SCUTIMER_BASEADDR;
+
+#define SCUTIMER_CONTROL_PRESCALER_MASK 0x0000FF00 /* Prescaler */
+#define SCUTIMER_CONTROL_PRESCALER_SHIFT 8
+#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK 0x00000002 /* Auto-reload */
+#define SCUTIMER_CONTROL_ENABLE_MASK 0x00000001 /* Timer enable */
+
+#define TIMER_LOAD_VAL 0xFFFFFFFF
+#define TIMER_PRESCALE 255
+#define TIMER_TICK_HZ (CONFIG_CPU_FREQ_HZ / 2 / TIMER_PRESCALE)
+
+int timer_init(void)
+{
+ const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
+ (TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
+ SCUTIMER_CONTROL_ENABLE_MASK;
+
+ /* Load the timer counter register */
+ writel(0xFFFFFFFF, &timer_base->counter);
+
+ /*
+ * Start the A9Timer device
+ * Enable Auto reload mode, Clear prescaler control bits
+ * Set prescaler value, Enable the decrementer
+ */
+ clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK,
+ emask);
+
+ /* Reset time */
+ gd->arch.lastinc = readl(&timer_base->counter) /
+ (TIMER_TICK_HZ / CONFIG_SYS_HZ);
+ gd->arch.tbl = 0;
+
+ return 0;
+}
+
+/*
+ * This function is derived from PowerPC code (read timebase as long long).
+ * On ARM it just returns the timer value.
+ */
+ulong get_timer_masked(void)
+{
+ ulong now;
+
+ now = readl(&timer_base->counter) / (TIMER_TICK_HZ / CONFIG_SYS_HZ);
+
+ if (gd->arch.lastinc >= now) {
+ /* Normal mode */
+ gd->arch.tbl += gd->arch.lastinc - now;
+ } else {
+ /* We have an overflow ... */
+ gd->arch.tbl += gd->arch.lastinc + TIMER_LOAD_VAL - now;
+ }
+ gd->arch.lastinc = now;
+
+ return gd->arch.tbl;
+}
+
+void __udelay(unsigned long usec)
+{
+ u32 countticks;
+ u32 timeend;
+ u32 timediff;
+ u32 timenow;
+
+ if (usec == 0)
+ return;
+
+ countticks = (u32) (((unsigned long long) TIMER_TICK_HZ * usec) /
+ 1000000);
+
+ /* decrementing timer */
+ timeend = readl(&timer_base->counter) - countticks;
+
+#if TIMER_LOAD_VAL != 0xFFFFFFFF
+ /* do not manage multiple overflow */
+ if (countticks >= TIMER_LOAD_VAL)
+ countticks = TIMER_LOAD_VAL - 1;
+#endif
+
+ do {
+ timenow = readl(&timer_base->counter);
+
+ if (timenow >= timeend) {
+ /* normal case */
+ timediff = timenow - timeend;
+ } else {
+ if ((TIMER_LOAD_VAL - timeend + timenow) <=
+ countticks) {
+ /* overflow */
+ timediff = TIMER_LOAD_VAL - timeend + timenow;
+ } else {
+ /* missed the exact match */
+ break;
+ }
+ }
+ } while (timediff > 0);
+}
+
+/* Timer without interrupts */
+ulong get_timer(ulong base)
+{
+ return get_timer_masked() - base;
+}
+
+/*
+ * 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)
+{
+ return CONFIG_SYS_HZ;
+}
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