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/**
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 * @file
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 *
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 * @brief RISC-V build-in timer
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 *
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 * @date 12.12.2019
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 * @author Anastasia Nizharadze
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 */
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#include <errno.h>
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#include <stdint.h>
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#include <asm/interrupts.h>
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#include <asm/regs.h>
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#include <framework/mod/options.h>
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#include <hal/clock.h>
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#include <hal/reg.h>
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#include <hal/system.h>
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#include <kernel/irq.h>
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#include <kernel/time/clock_source.h>
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#include <kernel/time/time.h>
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#include <drivers/interrupt/riscv_clint.h>
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#define COUNT_OFFSET  (RTC_CLOCK / JIFFIES_PERIOD)
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#define RTC_CLOCK     OPTION_GET(NUMBER, rtc_freq)
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#define OPENSBI_TIMER 0x54494D45
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static int clock_handler(unsigned int irq_nr, void *dev_id) {
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#if SMODE
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	register uintptr_t a7 asm("a7") = (uintptr_t)(OPENSBI_TIMER);
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	register uintptr_t a6 asm("a6") = (uintptr_t)(0);
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	register uintptr_t a0 asm("a0") = 0;
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	asm volatile("rdtime a0");
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	a0 = a0 + COUNT_OFFSET;
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	(void)a7;
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	(void)a6;
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	asm volatile("ecall");
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#else
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	clint_set_mtimecmp(clint_get_mtime() + COUNT_OFFSET);
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#endif
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	clock_tick_handler(dev_id);
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	return IRQ_HANDLED;
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}
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static int riscv_clock_setup(struct clock_source *cs) {
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#if SMODE
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	register uintptr_t a7 asm("a7") = (uintptr_t)(OPENSBI_TIMER);
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	register uintptr_t a6 asm("a6") = (uintptr_t)(0);
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	register uintptr_t a0 asm("a0") = 0;
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	asm volatile("rdtime a0");
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	a0 = a0 + COUNT_OFFSET;
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	(void)a7;
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	(void)a6;
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	asm volatile("ecall");
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#else
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	clint_set_mtimecmp(clint_get_mtime() + COUNT_OFFSET);
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#endif
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	enable_timer_interrupts();
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	return ENOERR;
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}
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static struct time_event_device riscv_event_device = {
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    .set_periodic = riscv_clock_setup,
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    .name = "riscv_clk",
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    .irq_nr = IRQ_TIMER,
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};
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CLOCK_SOURCE_DEF(riscv_clk, NULL, NULL, &riscv_event_device, NULL);
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RISCV_TIMER_IRQ_DEF(clock_handler, &CLOCK_SOURCE_NAME(riscv_clk));
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