From 102b0d2daa97dae68d3eed54d8fe37a9cc38a892 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 11:13:47 +0200 Subject: Adding upstream version 2.8.0+dfsg. Signed-off-by: Daniel Baumann --- drivers/delay_timer/delay_timer.c | 82 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 drivers/delay_timer/delay_timer.c (limited to 'drivers/delay_timer/delay_timer.c') diff --git a/drivers/delay_timer/delay_timer.c b/drivers/delay_timer/delay_timer.c new file mode 100644 index 0000000..a3fd7bf --- /dev/null +++ b/drivers/delay_timer/delay_timer.c @@ -0,0 +1,82 @@ +/* + * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include + +#include + +#include +#include + +/*********************************************************** + * The delay timer implementation + ***********************************************************/ +static const timer_ops_t *timer_ops; + +/*********************************************************** + * Delay for the given number of microseconds. The driver must + * be initialized before calling this function. + ***********************************************************/ +void udelay(uint32_t usec) +{ + assert((timer_ops != NULL) && + (timer_ops->clk_mult != 0U) && + (timer_ops->clk_div != 0U) && + (timer_ops->get_timer_value != NULL)); + + uint32_t start, delta; + uint64_t total_delta; + + 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((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(); + + } 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) +{ + assert((msec * 1000UL) < UINT32_MAX); + udelay(msec * 1000U); +} + +/*********************************************************** + * 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 != 0U) && + (ops_ptr->clk_div != 0U) && + (ops_ptr->get_timer_value != NULL)); + + timer_ops = ops_ptr; +} -- cgit v1.2.3