1 files changed, 66 insertions, 0 deletions
diff --git a/drivers/delay_timer/delay_timer.c b/drivers/delay_timer/delay_timer.c
new file mode 100644
index 00000000..43f5af7b
--- /dev/null
+++ b/drivers/delay_timer/delay_timer.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <delay_timer.h>
+#include <platform_def.h>
+
+/***********************************************************
+ * The delay timer implementation
+ ***********************************************************/
+static const timer_ops_t *ops;
+
+/***********************************************************
+ * Delay for the given number of microseconds. The driver must
+ * be initialized before calling this function.
+ ***********************************************************/
+void udelay(uint32_t usec)
+{
+	assert(ops != NULL &&
+		(ops->clk_mult != 0) &&
+		(ops->clk_div != 0) &&
+		(ops->get_timer_value != NULL));
+
+	uint32_t start, delta, total_delta;
+
+	assert(usec < UINT32_MAX / ops->clk_div);
+
+	start = ops->get_timer_value();
+
+	total_delta = (usec * ops->clk_div) / ops->clk_mult;
+
+	do {
+		/*
+		 * If the timer value wraps around, the subtraction will
+		 * overflow and it will still give the correct result.
+		 */
+		delta = start - ops->get_timer_value(); /* Decreasing counter */
+
+	} while (delta < total_delta);
+}
+
+/***********************************************************
+ * Delay for the given number of milliseconds. The driver must
+ * be initialized before calling this function.
+ ***********************************************************/
+void mdelay(uint32_t msec)
+{
+	udelay(msec*1000);
+}
+
+/***********************************************************
+ * Initialize the timer. The fields in the provided timer
+ * ops pointer must be valid.
+ ***********************************************************/
+void timer_init(const timer_ops_t *ops_ptr)
+{
+	assert(ops_ptr != NULL  &&
+		(ops_ptr->clk_mult != 0) &&
+		(ops_ptr->clk_div != 0) &&
+		(ops_ptr->get_timer_value != NULL));
+
+	ops = ops_ptr;
+}