diff options
Diffstat (limited to 'nuttx/configs/px4io/src/up_hrt.c')
| -rw-r--r-- | nuttx/configs/px4io/src/up_hrt.c | 664 |
1 files changed, 0 insertions, 664 deletions
diff --git a/nuttx/configs/px4io/src/up_hrt.c b/nuttx/configs/px4io/src/up_hrt.c deleted file mode 100644 index d0c46bd26..000000000 --- a/nuttx/configs/px4io/src/up_hrt.c +++ /dev/null @@ -1,664 +0,0 @@ -/**************************************************************************** - * - * Copyright (C) 2012 PX4 Development Team. All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. 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. - * 3. Neither the name PX4 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. - * - ****************************************************************************/ - -/** - * @file High-resolution timer callouts and timekeeping. - * - * This can use any general or advanced STM32 timer. - * - * Note that really, this could use systick too, but that's - * monopolised by NuttX and stealing it would just be awkward. - * - * We don't use the NuttX STM32 driver per se; rather, we - * claim the timer and then drive it directly. - */ - -#include <nuttx/config.h> -#include <nuttx/arch.h> -#include <nuttx/irq.h> - -#include <sys/types.h> -#include <stdbool.h> - -#include <assert.h> -#include <debug.h> -#include <time.h> -#include <queue.h> -#include <errno.h> -#include <string.h> - -#include <arch/board/board.h> -#include <arch/board/up_hrt.h> - -#include "chip.h" -#include "up_internal.h" -#include "up_arch.h" - -#include "stm32_internal.h" -#include "stm32_gpio.h" -#include "stm32_tim.h" - -#ifdef CONFIG_HRT_TIMER - -/* HRT configuration */ -#if HRT_TIMER == 1 -# define HRT_TIMER_BASE STM32_TIM1_BASE -# define HRT_TIMER_POWER_REG STM32_RCC_APB2ENR -# define HRT_TIMER_POWER_BIT RCC_APB2ENR_TIM1EN -# define HRT_TIMER_VECTOR STM32_IRQ_TIM1CC -# define HRT_TIMER_CLOCK STM32_APB2_TIM1_CLKIN -# if CONFIG_STM32_TIM1 -# error must not set CONFIG_STM32_TIM1=y and HRT_TIMER=1 -# endif -#elif HRT_TIMER == 2 -# define HRT_TIMER_BASE STM32_TIM2_BASE -# define HRT_TIMER_POWER_REG STM32_RCC_APB1ENR -# define HRT_TIMER_POWER_BIT RCC_APB2ENR_TIM2EN -# define HRT_TIMER_VECTOR STM32_IRQ_TIM2 -# define HRT_TIMER_CLOCK STM32_APB1_TIM2_CLKIN -# if CONFIG_STM32_TIM2 -# error must not set CONFIG_STM32_TIM2=y and HRT_TIMER=2 -# endif -#elif HRT_TIMER == 3 -# define HRT_TIMER_BASE STM32_TIM3_BASE -# define HRT_TIMER_POWER_REG STM32_RCC_APB1ENR -# define HRT_TIMER_POWER_BIT RCC_APB2ENR_TIM3EN -# define HRT_TIMER_VECTOR STM32_IRQ_TIM3 -# define HRT_TIMER_CLOCK STM32_APB1_TIM3_CLKIN -# if CONFIG_STM32_TIM3 -# error must not set CONFIG_STM32_TIM3=y and HRT_TIMER=3 -# endif -#elif HRT_TIMER == 4 -# define HRT_TIMER_BASE STM32_TIM4_BASE -# define HRT_TIMER_POWER_REG STM32_RCC_APB1ENR -# define HRT_TIMER_POWER_BIT RCC_APB2ENR_TIM4EN -# define HRT_TIMER_VECTOR STM32_IRQ_TIM4 -# define HRT_TIMER_CLOCK STM32_APB1_TIM4_CLKIN -# if CONFIG_STM32_TIM4 -# error must not set CONFIG_STM32_TIM4=y and HRT_TIMER=4 -# endif -#elif HRT_TIMER == 5 -# define HRT_TIMER_BASE STM32_TIM5_BASE -# define HRT_TIMER_POWER_REG STM32_RCC_APB1ENR -# define HRT_TIMER_POWER_BIT RCC_APB2ENR_TIM5EN -# define HRT_TIMER_VECTOR STM32_IRQ_TIM5 -# define HRT_TIMER_CLOCK STM32_APB1_TIM5_CLKIN -# if CONFIG_STM32_TIM5 -# error must not set CONFIG_STM32_TIM5=y and HRT_TIMER=5 -# endif -#elif HRT_TIMER == 8 -# define HRT_TIMER_BASE STM32_TIM8_BASE -# define HRT_TIMER_POWER_REG STM32_RCC_APB2ENR -# define HRT_TIMER_POWER_BIT RCC_APB2ENR_TIM8EN -# define HRT_TIMER_VECTOR STM32_IRQ_TIM8CC -# define HRT_TIMER_CLOCK STM32_APB2_TIM8_CLKIN -# if CONFIG_STM32_TIM8 -# error must not set CONFIG_STM32_TIM8=y and HRT_TIMER=6 -# endif -#elif HRT_TIMER == 9 -# define HRT_TIMER_BASE STM32_TIM9_BASE -# define HRT_TIMER_POWER_REG STM32_RCC_APB1ENR -# define HRT_TIMER_POWER_BIT RCC_APB2ENR_TIM9EN -# define HRT_TIMER_VECTOR STM32_IRQ_TIM1BRK -# define HRT_TIMER_CLOCK STM32_APB1_TIM9_CLKIN -# if CONFIG_STM32_TIM9 -# error must not set CONFIG_STM32_TIM9=y and HRT_TIMER=9 -# endif -#elif HRT_TIMER == 10 -# define HRT_TIMER_BASE STM32_TIM10_BASE -# define HRT_TIMER_POWER_REG STM32_RCC_APB1ENR -# define HRT_TIMER_POWER_BIT RCC_APB2ENR_TIM10EN -# define HRT_TIMER_VECTOR STM32_IRQ_TIM1UP -# define HRT_TIMER_CLOCK STM32_APB1_TIM10_CLKIN -# if CONFIG_STM32_TIM10 -# error must not set CONFIG_STM32_TIM11=y and HRT_TIMER=10 -# endif -#elif HRT_TIMER == 11 -# define HRT_TIMER_BASE STM32_TIM11_BASE -# define HRT_TIMER_POWER_REG STM32_RCC_APB1ENR -# define HRT_TIMER_POWER_BIT RCC_APB2ENR_TIM11EN -# define HRT_TIMER_VECTOR STM32_IRQ_TIM1TRGCOM -# define HRT_TIMER_CLOCK STM32_APB1_TIM11_CLKIN -# if CONFIG_STM32_TIM11 -# error must not set CONFIG_STM32_TIM11=y and HRT_TIMER=11 -# endif -#else -# error HRT_TIMER must be set in board.h if CONFIG_HRT_TIMER=y -#endif - -/* - * HRT clock must be a multiple of 1MHz greater than 1MHz - */ -#if (HRT_TIMER_CLOCK % 1000000) != 0 -# error HRT_TIMER_CLOCK must be a multiple of 1MHz -#endif -#if HRT_TIMER_CLOCK <= 1000000 -# error HRT_TIMER_CLOCK must be greater than 1MHz -#endif - -/* - * Minimum/maximum deadlines. - * - * These are suitable for use with a 16-bit timer/counter clocked - * at 1MHz. The high-resolution timer need only guarantee that it - * not wrap more than once in the 50ms period for absolute time to - * be consistently maintained. - * - * The minimum deadline must be such that the time taken between - * reading a time and writing a deadline to the timer cannot - * result in missing the deadline. - */ -#define HRT_INTERVAL_MIN 50 -#define HRT_INTERVAL_MAX 50000 - -/* - * Period of the free-running counter, in microseconds. - */ -#define HRT_COUNTER_PERIOD 65536 - -/* - * Scaling factor(s) for the free-running counter; convert an input - * in counts to a time in microseconds. - */ -#define HRT_COUNTER_SCALE(_c) (_c) - -/* - * Timer register accessors - */ -#define REG(_reg) (*(volatile uint32_t *)(HRT_TIMER_BASE + _reg)) - -#define rCR1 REG(STM32_GTIM_CR1_OFFSET) -#define rCR2 REG(STM32_GTIM_CR2_OFFSET) -#define rSMCR REG(STM32_GTIM_SMCR_OFFSET) -#define rDIER REG(STM32_GTIM_DIER_OFFSET) -#define rSR REG(STM32_GTIM_SR_OFFSET) -#define rEGR REG(STM32_GTIM_EGR_OFFSET) -#define rCCMR1 REG(STM32_GTIM_CCMR1_OFFSET) -#define rCCMR2 REG(STM32_GTIM_CCMR2_OFFSET) -#define rCCER REG(STM32_GTIM_CCER_OFFSET) -#define rCNT REG(STM32_GTIM_CNT_OFFSET) -#define rPSC REG(STM32_GTIM_PSC_OFFSET) -#define rARR REG(STM32_GTIM_ARR_OFFSET) -#define rCCR1 REG(STM32_GTIM_CCR1_OFFSET) -#define rCCR2 REG(STM32_GTIM_CCR2_OFFSET) -#define rCCR3 REG(STM32_GTIM_CCR3_OFFSET) -#define rCCR4 REG(STM32_GTIM_CCR4_OFFSET) -#define rDCR REG(STM32_GTIM_DCR_OFFSET) -#define rDMAR REG(STM32_GTIM_DMAR_OFFSET) - -/* - * Specific registers and bits used by HRT sub-functions - */ -#if HRT_TIMER_CHANNEL == 1 -# define rCCR_HRT rCCR1 /* compare register for HRT */ -# define DIER_HRT GTIM_DIER_CC1IE /* interrupt enable for HRT */ -# define SR_INT_HRT GTIM_SR_CC1IF /* interrupt status for HRT */ -#elif HRT_TIMER_CHANNEL == 2 -# define rCCR_HRT rCCR2 /* compare register for HRT */ -# define DIER_HRT GTIM_DIER_CC2IE /* interrupt enable for HRT */ -# define SR_INT_HRT GTIM_SR_CC2IF /* interrupt status for HRT */ -#elif HRT_TIMER_CHANNEL == 3 -# define rCCR_HRT rCCR3 /* compare register for HRT */ -# define DIER_HRT GTIM_DIER_CC3IE /* interrupt enable for HRT */ -# define SR_INT_HRT GTIM_SR_CC3IF /* interrupt status for HRT */ -#elif HRT_TIMER_CHANNEL == 4 -# define rCCR_HRT rCCR4 /* compare register for HRT */ -# define DIER_HRT GTIM_DIER_CC4IE /* interrupt enable for HRT */ -# define SR_INT_HRT GTIM_SR_CC4IF /* interrupt status for HRT */ -#else -# error HRT_TIMER_CHANNEL must be a value between 1 and 4 -#endif - -/* - * Queue of callout entries. - */ -static struct sq_queue_s callout_queue; - -/* - * The time corresponding to a counter value of zero, as of the - * last time that hrt_absolute_time() was called. - */ -static hrt_abstime base_time; - -/* timer-specific functions */ -static void hrt_tim_init(int timer); -static int hrt_tim_isr(int irq, void *context); - -/* callout list manipulation */ -static void hrt_call_enter(struct hrt_call *entry); -static void hrt_call_reschedule(void); -static void hrt_call_invoke(void); - -/* - * Specific registers and bits used by PPM sub-functions - */ -#ifdef CONFIG_HRT_PPM -# include <arch/board/drv_ppm_input.h> - -/* - * If the timer hardware doesn't support GTIM_CCER_CCxNP, then we will work around it. - */ -# ifndef GTIM_CCER_CC1NP -# define GTIM_CCER_CC1NP 0 -# define GTIM_CCER_CC2NP 0 -# define GTIM_CCER_CC3NP 0 -# define GTIM_CCER_CC4NP 0 -# define PPM_EDGE_FLIP -# endif - -# if HRT_PPM_CHANNEL == 1 -# define rCCR_PPM rCCR1 /* capture register for PPM */ -# define DIER_PPM GTIM_DIER_CC1IE /* capture interrupt (non-DMA mode) */ -# define SR_INT_PPM GTIM_SR_CC1IF /* capture interrupt (non-DMA mode) */ -# define SR_OVF_PPM GTIM_SR_CC1OF /* capture overflow (non-DMA mode) */ -# define CCMR1_PPM 1 /* on TI1 */ -# define CCMR2_PPM 0 -# define CCER_PPM (GTIM_CCER_CC1E | GTIM_CCER_CC1P | GTIM_CCER_CC1NP) /* CC1, both edges */ -# define CCER_PPM_FLIP GTIM_CCER_CC1P -# elif HRT_PPM_CHANNEL == 2 -# define rCCR_PPM rCCR2 /* capture register for PPM */ -# define DIER_PPM GTIM_DIER_CC2IE /* capture interrupt (non-DMA mode) */ -# define SR_INT_PPM GTIM_SR_CC2IF /* capture interrupt (non-DMA mode) */ -# define SR_OVF_PPM GTIM_SR_CC2OF /* capture overflow (non-DMA mode) */ -# define CCMR1_PPM 2 /* on TI2 */ -# define CCMR2_PPM 0 -# define CCER_PPM (GTIM_CCER_CC2E | GTIM_CCER_CC2P | GTIM_CCER_CC2NP) /* CC2, both edges */ -# define CCER_PPM_FLIP GTIM_CCER_CC2P -# elif HRT_PPM_CHANNEL == 3 -# define rCCR_PPM rCCR3 /* capture register for PPM */ -# define DIER_PPM GTIM_DIER_CC3IE /* capture interrupt (non-DMA mode) */ -# define SR_INT_PPM GTIM_SR_CC3IF /* capture interrupt (non-DMA mode) */ -# define SR_OVF_PPM GTIM_SR_CC3OF /* capture overflow (non-DMA mode) */ -# define CCMR1_PPM 0 -# define CCMR2_PPM 1 /* on TI3 */ -# define CCER_PPM (GTIM_CCER_CC3E | GTIM_CCER_CC3P | GTIM_CCER_CC3NP) /* CC3, both edges */ -# define CCER_PPM_FLIP GTIM_CCER_CC3P -# elif HRT_PPM_CHANNEL == 4 -# define rCCR_PPM rCCR4 /* capture register for PPM */ -# define DIER_PPM GTIM_DIER_CC4IE /* capture interrupt (non-DMA mode) */ -# define SR_INT_PPM GTIM_SR_CC4IF /* capture interrupt (non-DMA mode) */ -# define SR_OVF_PPM GTIM_SR_CC4OF /* capture overflow (non-DMA mode) */ -# define CCMR1_PPM 0 -# define CCMR2_PPM 2 /* on TI4 */ -# define CCER_PPM (GTIM_CCER_CC4E | GTIM_CCER_CC4P | GTIM_CCER_CC4NP) /* CC4, both edges */ -# define CCER_PPM_FLIP GTIM_CCER_CC4P -# else -# error HRT_PPM_CHANNEL must be a value between 1 and 4 if CONFIG_HRT_PPM is set -# endif -#else -/* disable the PPM configuration */ -# define rCCR_PPM 0 -# define DIER_PPM 0 -# define SR_INT_PPM 0 -# define SR_OVF_PPM 0 -# define CCMR1_PPM 0 -# define CCMR2_PPM 0 -# define CCER_PPM 0 -#endif /* CONFIG_HRT_PPM */ - -/* - * Initialise the timer we are going to use. - * - * We expect that we'll own one of the reduced-function STM32 general - * timers, and that we can use channel 1 in compare mode. - */ -static void -hrt_tim_init(int timer) -{ - /* clock/power on our timer */ - modifyreg32(HRT_TIMER_POWER_REG, 0, HRT_TIMER_POWER_BIT); - - /* claim our interrupt vector */ - irq_attach(HRT_TIMER_VECTOR, hrt_tim_isr); - - /* disable and configure the timer */ - rCR1 = 0; - rCR2 = 0; - rSMCR = 0; - rDIER = DIER_HRT | DIER_PPM; - rCCER = 0; /* unlock CCMR* registers */ - rCCMR1 = CCMR1_PPM; - rCCMR2 = CCMR2_PPM; - rCCER = CCER_PPM; - rDCR = 0; - - /* configure the timer to free-run at 1MHz */ - rPSC = (HRT_TIMER_CLOCK / 1000000) - 1; /* this really only works for whole-MHz clocks */ - - /* run the full span of the counter */ - rARR = 0xffff; - - /* set an initial capture a little ways off */ - rCCR_HRT = 1000; - - /* generate an update event; reloads the counter, all registers */ - rEGR = GTIM_EGR_UG; - - /* enable the timer */ - rCR1 = GTIM_CR1_CEN; - - /* enable interrupts */ - up_enable_irq(HRT_TIMER_VECTOR); -} - -/* - * Handle the compare interupt by calling the callout dispatcher - * and then re-scheduling the next deadline. - */ -static int -hrt_tim_isr(int irq, void *context) -{ - uint32_t status; - - /* copy interrupt status */ - status = rSR; - - /* ack the interrupts we just read */ - rSR = ~status; - -#ifdef CONFIG_HRT_PPM - /* was this a PPM edge? */ - if (status & (SR_INT_PPM | SR_OVF_PPM)) { - - /* if required, flip edge sensitivity */ -# ifdef PPM_EDGE_FLIP - rCCER ^= CCER_PPM_FLIP; -# endif - - /* feed the edge to the PPM decoder */ - ppm_input_decode(status & SR_OVF_PPM, rCCR_PPM); - } -#endif - - /* was this a timer tick? */ - if (status & SR_INT_HRT) { - /* run any callouts that have met their deadline */ - hrt_call_invoke(); - - /* and schedule the next interrupt */ - hrt_call_reschedule(); - } - - return OK; -} - -/* - * Fetch a never-wrapping absolute time value in microseconds from - * some arbitrary epoch shortly after system start. - */ -hrt_abstime -hrt_absolute_time(void) -{ - static uint32_t last_count; - uint32_t count; - uint32_t flags = irqsave(); - - count = rCNT; - - //lldbg("count %u last_count %u\n", count, last_count); - - /* This simple test is made possible by the guarantee that - * we are always called at least once per counter period. - */ - if (count < last_count) - base_time += HRT_COUNTER_PERIOD; - - last_count = count; - - irqrestore(flags); - - return HRT_COUNTER_SCALE(base_time + count); -} - -/* - * Convert a timespec to absolute time - */ -hrt_abstime -ts_to_abstime(struct timespec *ts) -{ - hrt_abstime result; - - result = (hrt_abstime)(ts->tv_sec) * 1000000; - result += ts->tv_nsec / 1000; - - return result; -} - -/* - * Convert absolute time to a timespec. - */ -void -abstime_to_ts(struct timespec *ts, hrt_abstime abstime) -{ - ts->tv_sec = abstime / 1000000; - abstime -= ts->tv_sec * 1000000; - ts->tv_nsec = abstime * 1000; -} - -/* - * Initalise the high-resolution timing module. - */ -void -hrt_init(int timer) -{ - sq_init(&callout_queue); - hrt_tim_init(timer); -} - -/* - * Call callout(arg) after interval has elapsed. - */ -void -hrt_call_after(struct hrt_call *entry, hrt_abstime delay, hrt_callout callout, void *arg) -{ - entry->deadline = hrt_absolute_time() + delay; - entry->period = 0; - entry->callout = callout; - entry->arg = arg; - - hrt_call_enter(entry); -} - -/* - * Call callout(arg) at calltime. - */ -void -hrt_call_at(struct hrt_call *entry, hrt_abstime calltime, hrt_callout callout, void *arg) -{ - entry->deadline = calltime; - entry->period = 0; - entry->callout = callout; - entry->arg = arg; - - hrt_call_enter(entry); -} - -/* - * Call callout(arg) every period. - */ -void -hrt_call_every(struct hrt_call *entry, hrt_abstime delay, hrt_abstime interval, hrt_callout callout, void *arg) -{ - entry->deadline = hrt_absolute_time() + delay; - entry->period = interval; - entry->callout = callout; - entry->arg = arg; - - hrt_call_enter(entry); -} - -/* - * If this returns true, the call has been invoked and removed from the callout list. - * - * Always returns false for repeating callouts. - */ -bool -hrt_called(struct hrt_call *entry) -{ - bool result; - - irqstate_t flags = irqsave(); - result = (entry->deadline == 0); - irqrestore(flags); - - return result; -} - -/* - * Remove the entry from the callout list. - */ -void -hrt_cancel(struct hrt_call *entry) -{ - irqstate_t flags = irqsave(); - - sq_rem(&entry->link, &callout_queue); - entry->deadline = 0; - - /* if this is a periodic call being removed by the callout, prevent it from - * being re-entered when the callout returns. - */ - entry->period = 0; - - irqrestore(flags); -} - -static void -hrt_call_enter(struct hrt_call *entry) -{ - irqstate_t flags = irqsave(); - struct hrt_call *call, *next; - - call = (struct hrt_call *)sq_peek(&callout_queue); - - if ((call == NULL) || (entry->deadline < call->deadline)) { - sq_addfirst(&entry->link, &callout_queue); - //lldbg("call enter at head, reschedule\n"); - /* we changed the next deadline, reschedule the timer event */ - hrt_call_reschedule(); - } else { - do { - next = (struct hrt_call *)sq_next(&call->link); - if ((next == NULL) || (entry->deadline < next->deadline)) { - //lldbg("call enter after head\n"); - sq_addafter(&call->link, &entry->link, &callout_queue); - break; - } - } while ((call = next) != NULL); - } - - //lldbg("scheduled\n"); - irqrestore(flags); -} - -static void -hrt_call_invoke(void) -{ - struct hrt_call *call; - hrt_abstime deadline; - - while (true) { - /* get the current time */ - hrt_abstime now = hrt_absolute_time(); - - call = (struct hrt_call *)sq_peek(&callout_queue); - if (call == NULL) - break; - if (call->deadline > now) - break; - - sq_rem(&call->link, &callout_queue); - //lldbg("call pop\n"); - - /* save the intended deadline for periodic calls */ - deadline = call->deadline; - - /* zero the deadline, as the call has occurred */ - call->deadline = 0; - - /* invoke the callout (if there is one) */ - if (call->callout) { - //lldbg("call %p: %p(%p)\n", call, call->callout, call->arg); - call->callout(call->arg); - } - - /* if the callout has a non-zero period, it has to be re-entered */ - if (call->period != 0) { - call->deadline = deadline + call->period; - hrt_call_enter(call); - } - } -} - -/* - * Reschedule the next timer interrupt. - * - * This routine must be called with interrupts disabled. - */ -static void -hrt_call_reschedule() -{ - hrt_abstime now = hrt_absolute_time(); - struct hrt_call *next = (struct hrt_call *)sq_peek(&callout_queue); - hrt_abstime deadline = now + HRT_INTERVAL_MAX; - - /* - * Determine what the next deadline will be. - * - * Note that we ensure that this will be within the counter - * period, so that when we truncate all but the low 16 bits - * the next time the compare matches it will be the deadline - * we want. - * - * It is important for accurate timekeeping that the compare - * interrupt fires sufficiently often that the base_time update in - * hrt_absolute_time runs at least once per timer period. - */ - if (next != NULL) { - //lldbg("entry in queue\n"); - if (next->deadline <= (now + HRT_INTERVAL_MIN)) { - //lldbg("pre-expired\n"); - /* set a minimal deadline so that we call ASAP */ - deadline = now + HRT_INTERVAL_MIN; - } else if (next->deadline < deadline) { - //lldbg("due soon\n"); - deadline = next->deadline; - } - } - //lldbg("schedule for %u at %u\n", (unsigned)(deadline & 0xffffffff), (unsigned)(now & 0xffffffff)); - - /* set the new compare value */ - rCCR_HRT = deadline & 0xffff; -} - -#endif /* CONFIG_HRT_TIMER */ |