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/**
* @file
*
* @ingroup bsp_clock
*
* @brief riscv clock support.
*/
/*
* riscv_generic Clock driver
*
* COPYRIGHT (c) 2015 Hesham Alatary <hesham@alumni.york.ac.uk>
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <rtems.h>
#include <bsp.h>
#include <bsp/irq.h>
#include <rtems/score/riscv-utility.h>
#include <rtems/score/cpu.h>
#include <rtems/timecounter.h>
/* The number of clock cycles before generating a tick timer interrupt. */
#define TTMR_NUM_OF_CLOCK_TICKS_INTERRUPT 1000
#define RISCV_CLOCK_CYCLE_TIME_NANOSECONDS 1
static struct timecounter riscv_generic_tc;
/* CPU counter */
static CPU_Counter_ticks cpu_counter_ticks;
/* This prototype is added here to Avoid warnings */
void Clock_isr(void *arg);
static void riscv_generic_clock_at_tick(void)
{
REG(MTIME_MM) = 0;
REG(MTIMECMP_MM) = TTMR_NUM_OF_CLOCK_TICKS_INTERRUPT;
cpu_counter_ticks += TTMR_NUM_OF_CLOCK_TICKS_INTERRUPT * 10000;
}
static void riscv_generic_clock_handler_install(proc_ptr new_isr)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
_CPU_ISR_install_vector(RISCV_MACHINE_TIMER_INTERRUPT,
new_isr,
NULL);
if (sc != RTEMS_SUCCESSFUL) {
rtems_fatal_error_occurred(0xdeadbeef);
}
}
static uint32_t riscv_generic_get_timecount(struct timecounter *tc)
{
uint32_t ticks_since_last_timer_interrupt = REG(MTIME_MM);
return cpu_counter_ticks + ticks_since_last_timer_interrupt;
}
CPU_Counter_ticks _CPU_Counter_read(void)
{
return riscv_generic_get_timecount(NULL);
}
static void riscv_generic_clock_initialize(void)
{
uint32_t mtimecmp = TTMR_NUM_OF_CLOCK_TICKS_INTERRUPT;
uint64_t frequency = (1000000000 / RISCV_CLOCK_CYCLE_TIME_NANOSECONDS);
REG(MTIME_MM) = 0;
REG(MTIMECMP_MM) = TTMR_NUM_OF_CLOCK_TICKS_INTERRUPT;
/* Enable mtimer interrupts */
set_csr(mie, MIP_MTIP);
set_csr(mip, MIP_MTIP);
/* Initialize timecounter */
riscv_generic_tc.tc_get_timecount = riscv_generic_get_timecount;
riscv_generic_tc.tc_counter_mask = 0xffffffff;
riscv_generic_tc.tc_frequency = frequency;
riscv_generic_tc.tc_quality = RTEMS_TIMECOUNTER_QUALITY_CLOCK_DRIVER;
rtems_timecounter_install(&riscv_generic_tc);
}
CPU_Counter_ticks _CPU_Counter_difference(
CPU_Counter_ticks second,
CPU_Counter_ticks first
)
{
return second - first;
}
#define Clock_driver_support_at_tick() riscv_generic_clock_at_tick()
#define Clock_driver_support_initialize_hardware() riscv_generic_clock_initialize()
#define Clock_driver_support_install_isr(isr) \
riscv_generic_clock_handler_install(isr)
#include "../../../shared/dev/clock/clockimpl.h"
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