1 files changed, 71 insertions, 0 deletions

diff --git a/arch/arm/lib/delay.c b/arch/arm/lib/delay.c
new file mode 100644
index 000000000000..d6dacc69254e
--- /dev/null
+++ b/arch/arm/lib/delay.c
@@ -0,0 +1,71 @@
+/*
+ * Delay loops based on the OpenRISC implementation.
+ *
+ * Copyright (C) 2012 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/timex.h>
+
+/*
+ * Default to the loop-based delay implementation.
+ */
+struct arm_delay_ops arm_delay_ops = {
+        .delay          = __loop_delay,
+        .const_udelay   = __loop_const_udelay,
+        .udelay         = __loop_udelay,
+};
+
+#ifdef ARCH_HAS_READ_CURRENT_TIMER
+static void __timer_delay(unsigned long cycles)
+{
+        cycles_t start = get_cycles();
+
+        while ((get_cycles() - start) < cycles)
+                cpu_relax();
+}
+
+static void __timer_const_udelay(unsigned long xloops)
+{
+        unsigned long long loops = xloops;
+        loops *= loops_per_jiffy;
+        __timer_delay(loops >> UDELAY_SHIFT);
+}
+
+static void __timer_udelay(unsigned long usecs)
+{
+        __timer_const_udelay(usecs * UDELAY_MULT);
+}
+
+void __init init_current_timer_delay(unsigned long freq)
+{
+        pr_info("Switching to timer-based delay loop\n");
+        lpj_fine                        = freq / HZ;
+        arm_delay_ops.delay             = __timer_delay;
+        arm_delay_ops.const_udelay      = __timer_const_udelay;
+        arm_delay_ops.udelay            = __timer_udelay;
+}
+
+unsigned long __cpuinit calibrate_delay_is_known(void)
+{
+        return lpj_fine;
+}
+#endif