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/*
* Copyright (c) 2011 - 2014 The Linux Foundation. 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 Google, Inc. 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 OWNER 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 <delay.h>
#include <soc/iomap.h>
#include <soc/ipq_timer.h>
#include <timer.h>
/*
* DGT runs at 25 MHz / 4, or 6.25 ticks per microsecond
*/
#define DGT_MHZ_NUM 25
#define DGT_MHZ_DEN 4
#define TIMER_TICKS(us) ((DGT_MHZ_NUM*(us) + (DGT_MHZ_DEN - 1)) / DGT_MHZ_DEN)
#define TIMER_USECS(ticks) (DGT_MHZ_DEN*(ticks) / DGT_MHZ_NUM)
/* Clock divider values for the timer. */
#define DGT_CLK_DIV_1 0
#define DGT_CLK_DIV_2 1
#define DGT_CLK_DIV_3 2
#define DGT_CLK_DIV_4 3
/**
* init_timer - initialize timer
*/
void init_timer(void)
{
/* disable timer */
writel_i(0, DGT_ENABLE);
/* DGT uses TCXO source which is 25MHz.
* The timer should run at 1/4th the frequency of TCXO
* according to clock plan.
* Set clock divider to 4.
*/
writel_i(DGT_CLK_DIV_4, DGT_CLK_CTL);
/* Enable timer */
writel_i(0, DGT_CLEAR);
writel_i(DGT_ENABLE_EN, DGT_ENABLE);
}
/**
* udelay - generates micro second delay.
* @param usec: delay duration in microseconds
*/
void udelay(unsigned int usec)
{
uint32_t now;
uint32_t last;
uint32_t ticks;
uint32_t curr_ticks = 0;
/* Calculate number of ticks required. */
ticks = TIMER_TICKS(usec);
/* Obtain the current timer value. */
last = readl_i(DGT_COUNT_VAL);
/* Loop until the right number of ticks. */
while (curr_ticks < ticks) {
now = readl_i(DGT_COUNT_VAL);
curr_ticks += now - last;
last = now;
}
}
void timer_monotonic_get(struct mono_time *mt)
{
mono_time_set_usecs(mt, TIMER_USECS(readl_i(DGT_COUNT_VAL)));
}
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