diff options
Diffstat (limited to 'drivers/delay_timer')
| -rw-r--r-- | drivers/delay_timer/delay_timer.c | 87 |
1 files changed, 87 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..0bee876f --- /dev/null +++ b/drivers/delay_timer/delay_timer.c @@ -0,0 +1,87 @@ +/* + * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * + * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * Neither the name of ARM nor the names of its contributors may be used + * to endorse or promote products derived from this software without specific + * prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#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 != 0 && + (ops->clk_mult != 0) && + (ops->clk_div != 0) && + (ops->get_timer_value != 0)); + + uint32_t start, cnt, delta, delta_us; + + /* counter is decreasing */ + start = ops->get_timer_value(); + do { + cnt = ops->get_timer_value(); + if (cnt > start) { + delta = UINT32_MAX - cnt; + delta += start; + } else + delta = start - cnt; + delta_us = (delta * ops->clk_mult) / ops->clk_div; + } while (delta_us < usec); +} + +/*********************************************************** + * 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 != 0 && + (ops_ptr->clk_mult != 0) && + (ops_ptr->clk_div != 0) && + (ops_ptr->get_timer_value != 0)); + + ops = ops_ptr; +} |