4b8bed320d
The comment that PRECISION is too low when the assert fails was wrong. PRECISION should have no influence on it. Signed-off-by: Gerwin Klein <gerwin.klein@proofcraft.systems>
88 lines
2.2 KiB
C
88 lines
2.2 KiB
C
/*
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* Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
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*
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* SPDX-License-Identifier: GPL-2.0-only
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*/
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#pragma once
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#include <util.h>
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#include <config.h>
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#include <model/statedata.h>
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#ifndef CONFIG_KERNEL_MCS
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#error "This driver should only be selected for MCS kernel"
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#endif /* CONFIG_KERNEL_MCS */
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/* ARM Cortex-A9 MPCore global timer driver
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* Documentation for this timer is available in
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* the Cortex-A9 MPCore Technical Reference Manual
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* section "Global Timer Counter Registers"
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*/
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struct timer {
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uint32_t countLower;
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uint32_t countUpper;
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uint32_t control;
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uint32_t isr;
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uint32_t comparatorLower;
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uint32_t comparatorUpper;
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uint32_t autoInc;
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};
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typedef volatile struct timer timer_t;
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extern timer_t *const globalTimer;
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enum control {
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ENABLE = 0,
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COMP_ENABLE = 1,
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IRQ_ENABLE = 2,
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AUTO_INC = 3,
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RESERVED = 4,
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PRESCALER = 8,
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RESERVED_2 = 16
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};
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/** DONT_TRANSLATE */
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static inline ticks_t getCurrentTime(void)
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{
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uint32_t upper, upper2, lower;
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upper = globalTimer->countUpper;
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lower = globalTimer->countLower;
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upper2 = globalTimer->countUpper;
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/* account for race: upper could have increased while we
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* read lower */
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if (upper != upper2) {
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lower = globalTimer->countLower;
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}
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return (((ticks_t) upper2 << 32llu) + (ticks_t) lower);
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}
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/** DONT_TRANSLATE */
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static inline void setDeadline(ticks_t deadline)
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{
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/* disable cmp */
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globalTimer->control &= ~(BIT(COMP_ENABLE));
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/* set low bits */
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globalTimer->comparatorLower = (uint32_t) deadline;
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/* set high bits */
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globalTimer->comparatorUpper = (uint32_t)(deadline >> 32llu);
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/* enable cmp */
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globalTimer->control |= BIT(COMP_ENABLE);
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/* Assert that either the deadline is in the future or that the IRQ has already been raised.
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This should be guaranteed by hardware from r2p0 on of the Cortex-A9 MPCore Technical
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Reference Manual (r2p0 published in 2009) */
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assert(getCurrentTime() < deadline || globalTimer->isr == 1u);
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}
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/** DONT_TRANSLATE */
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static inline void ackDeadlineIRQ(void)
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{
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/* disable cmp */
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globalTimer->control &= ~(BIT(COMP_ENABLE));
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/* ack the isr */
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globalTimer->isr = 1;
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}
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