Merge "TF-A: Fix non-standard frequency issue in udelay" into integration
diff --git a/drivers/delay_timer/delay_timer.c b/drivers/delay_timer/delay_timer.c
index 8c2996e..a3fd7bf 100644
--- a/drivers/delay_timer/delay_timer.c
+++ b/drivers/delay_timer/delay_timer.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -27,23 +27,32 @@
(timer_ops->clk_div != 0U) &&
(timer_ops->get_timer_value != NULL));
- uint32_t start, delta, total_delta;
+ uint32_t start, delta;
+ uint64_t total_delta;
- assert(usec < (UINT32_MAX / timer_ops->clk_div));
+ assert(usec < (UINT64_MAX / timer_ops->clk_div));
start = timer_ops->get_timer_value();
/* Add an extra tick to avoid delaying less than requested. */
total_delta =
- div_round_up(usec * timer_ops->clk_div,
+ div_round_up((uint64_t)usec * timer_ops->clk_div,
timer_ops->clk_mult) + 1U;
+ /*
+ * Precaution for the total_delta ~ UINT32_MAX and the fact that we
+ * cannot catch every tick of the timer.
+ * For example 100MHz timer over 25MHz APB will miss at least 4 ticks.
+ * 1000U is an arbitrary big number which is believed to be sufficient.
+ */
+ assert(total_delta < (UINT32_MAX - 1000U));
do {
/*
* If the timer value wraps around, the subtraction will
* overflow and it will still give the correct result.
+ * delta is decreasing counter
*/
- delta = start - timer_ops->get_timer_value(); /* Decreasing counter */
+ delta = start - timer_ops->get_timer_value();
} while (delta < total_delta);
}
@@ -54,6 +63,7 @@
***********************************************************/
void mdelay(uint32_t msec)
{
+ assert((msec * 1000UL) < UINT32_MAX);
udelay(msec * 1000U);
}