/* * * 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))); }