93 lines
1.7 KiB
C++
93 lines
1.7 KiB
C++
/*
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* \brief Timer driver for core
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* \author Sebastian Sumpf
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* \date 2015-08-22
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*/
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/*
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* Copyright (C) 2015-2017 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU Affero General Public License version 3.
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*/
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#ifndef _CORE__SPEC__RISCV__TIMER_H_
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#define _CORE__SPEC__RISCV__TIMER_H_
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/* base-hw includes */
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#include <kernel/types.h>
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#include <hw/spec/riscv/machine_call.h>
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/* Genode includes */
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#include <base/stdint.h>
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namespace Genode { class Timer; }
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/**
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* Timer driver for core
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*/
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struct Genode::Timer
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{
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private:
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using time_t = Kernel::time_t;
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enum {
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SPIKE_TIMER_HZ = 500000,
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TICS_PER_MS = SPIKE_TIMER_HZ / 1000,
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};
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addr_t _timeout = 0;
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addr_t _stime()
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{
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addr_t t;
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asm volatile ("csrr %0, stime\n" : "=r"(t));
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return t;
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}
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public:
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Timer()
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{
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/* enable timer interrupt */
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enum { STIE = 0x20 };
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asm volatile ("csrs sie, %0" : : "r"(STIE));
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}
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/**
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* Start single timeout run
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*
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* \param tics delay of timer interrupt
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*/
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void start_one_shot(time_t const tics, unsigned const)
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{
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_timeout = _stime() + tics;
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Hw::set_sys_timer(_timeout);
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}
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time_t tics_to_us(time_t const tics) const {
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return (tics / TICS_PER_MS) * 1000; }
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time_t us_to_tics(time_t const us) const {
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return (us / 1000) * TICS_PER_MS; }
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time_t max_value() { return (addr_t)~0; }
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/**
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* Return current native timer value
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*/
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time_t value(unsigned const)
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{
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addr_t time = _stime();
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return time < _timeout ? _timeout - time : 0;
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}
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static unsigned interrupt_id(unsigned const) { return 1; }
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};
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namespace Kernel { class Timer : public Genode::Timer { }; }
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#endif /* _CORE__SPEC__RISCV__TIMER_H_ */
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