Files
TencentOS-tiny/arch/risc-v/rv32i/port_c.c
2019-09-18 12:53:38 +08:00

149 lines
3.5 KiB
C

/*
* port_c.c
*
* Created on: Sep 9, 2019
* Author: ace
*/
#include "riscv_encoding.h"
#include <tos.h>
#define CLINT_CTRL_ADDR 0x2000000
#define CLINT_MSIP 0x0000
#define CLINT_MTIMECMP 0x4000
#define CLINT_MTIME 0xBFF8
static uint32_t mtime_lo(void)
{
return *(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIME);
}
static uint32_t mtime_hi(void)
{
return *(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIME + 4);
}
uint64_t get_mtime_val()
{
while (1) {
uint32_t hi = mtime_hi();
uint32_t lo = mtime_lo();
uint32_t nhi = mtime_hi();
if (hi == nhi) {
return (((uint64_t)hi) << 32) | lo;
} {
uint32_t a = hi;
uint32_t b = nhi;
}
}
}
void set_mtimecmp_lo(uint32_t v)
{
*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP) = v;
}
void set_mtimecmp_hi(uint32_t v)
{
*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 4) = v;
}
void set_mtimecmp_val(uint64_t v)
{
uint32_t hi = (v >> 32) & 0xFFFFFFFF;
uint32_t lo = (v >> 0) & 0xFFFFFFFF;
set_mtimecmp_lo(0xFFFFFFFF); // No smaller than old value.
set_mtimecmp_hi(hi); // No smaller than new value.
set_mtimecmp_lo(lo); // New value.
}
__PORT__ void port_systick_config(uint32_t cycle_per_tick)
{
#if 0
asm("csrc mie, %0"::"r"(MIP_MTIP));
#if 1
uint64_t mtime = get_mtime_val();
#else
static uint64_t last_mtime = 0;
if(last_mtime == 0) {
last_mtime = get_mtime_val();
}
uint64_t mtime = get_mtime_val();
if((mtime - last_mtime)/cycle_per_tick >= 4) {
mtime = last_mtime+2*cycle_per_tick;
}
last_mtime = mtime;
#endif
uint64_t mtimecmp;
do {
tick_inc();
mtimecmp = ((uint64_t)tos_get_tick())* cycle_per_tick;
} while(mtimecmp <= mtime);
set_mtimecmp_val(mtimecmp);
asm("csrs mie, %0"::"r"(MIP_MTIP));
#endif
#if 0
clear_csr(mie, MIP_MTIP);
static uint64_t then = 0;
volatile uint64_t * mtime = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIME);
volatile uint64_t * mtimecmp = (uint64_t*) (CLINT_CTRL_ADDR + CLINT_MTIMECMP);
if(then != 0) {
//next timer irq is 1 second from previous
then += 1*cycle_per_tick;
} else{ //first time setting the timer
uint64_t now = *mtime;
then = now + 1*cycle_per_tick;
}
*mtimecmp = then;
set_csr(mie, MIP_MTIP);
#endif
//asm("csrc mie, %0"::"r"(MIP_MTIP));
#if 0
uint64_t next_tick = get_mtime_val();
next_tick += cycle_per_tick;
set_mtimecmp_val(next_tick);
#endif
#if 0
uint64_t new_tick = get_mtime_val() + cycle_per_tick;
uint64_t tick = 0;
if(new_tick - next_tick > 50000) {
tick = get_mtime_val() + cycle_per_tick;
}
next_tick = new_tick;
set_mtimecmp_val(next_tick);
#endif
#if 1
// this is illegal in ricsv-32
// it cost cpu read two times, first mtime_lo and then mtime_hi
// if mtime_lo == 0xFFFFFFFF and mtime_hi = 0 at first read
// then mtime_lo == 0 and mtime_hi = 1 at next read
// the result will be 0x1FFFFFFFF, not 0x100000000
//*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 4) = 0xFFFFFFFF;
//*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 0) = 0xFFFFFFFF;
uint64_t mtime = *(volatile uint64_t *)(CLINT_CTRL_ADDR + CLINT_MTIME);
mtime += cycle_per_tick;
*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 4) = (mtime >> 32) & 0xFFFFFFFF;
asm("csrc mip, %0"::"r"(MIP_MTIP));
*(volatile uint32_t *)(CLINT_CTRL_ADDR + CLINT_MTIMECMP + 0) = (mtime >> 0) & 0xFFFFFFFF;
//asm("csrc mip, %0"::"r"(MIP_MTIP));
#endif
//asm("csrs mie, %0"::"r"(MIP_MTIP));
}
__PORT__ void port_systick_priority_set(uint32_t prio)
{
//NVIC_SetPriority(SysTick_IRQn, prio);
}