117 lines
2.1 KiB
C
117 lines
2.1 KiB
C
#include <stdint.h>
|
|
#include <stdio.h>
|
|
#include <unistd.h>
|
|
|
|
#include "platform.h"
|
|
#include "encoding.h"
|
|
|
|
extern int main(int argc, char** argv);
|
|
extern void trap_entry();
|
|
|
|
static unsigned long mtime_lo(void)
|
|
{
|
|
unsigned long ret;
|
|
__asm volatile("rdtime %0":"=r"(ret));
|
|
return ret;
|
|
}
|
|
|
|
|
|
#if __riscv_xlen==32
|
|
|
|
static uint32_t mtime_hi(void)
|
|
{
|
|
unsigned long ret;
|
|
__asm volatile("rdtimeh %0":"=r"(ret));
|
|
return ret;
|
|
}
|
|
|
|
uint64_t get_timer_value()
|
|
{
|
|
while (1) {
|
|
uint32_t hi = mtime_hi();
|
|
uint32_t lo = mtime_lo();
|
|
if (hi == mtime_hi())
|
|
return ((uint64_t)hi << 32) | lo;
|
|
}
|
|
}
|
|
|
|
#elif __riscv_xlen==64
|
|
|
|
uint64_t get_timer_value()
|
|
{
|
|
return mtime_lo();
|
|
}
|
|
|
|
#endif
|
|
|
|
unsigned long get_timer_freq()
|
|
{
|
|
return 32768;
|
|
}
|
|
|
|
unsigned long get_cpu_freq()
|
|
{
|
|
return 10000000;
|
|
}
|
|
|
|
void init_pll(void){
|
|
|
|
}
|
|
|
|
static void uart_init(size_t baud_rate)
|
|
{
|
|
GPIO_REG(GPIO_IOF_SEL) &= ~IOF0_UART0_MASK;
|
|
GPIO_REG(GPIO_IOF_EN) |= IOF0_UART0_MASK;
|
|
UART0_REG(UART_REG_DIV) = get_cpu_freq() / baud_rate - 1;
|
|
UART0_REG(UART_REG_TXCTRL) |= UART_TXEN;
|
|
}
|
|
|
|
#ifdef USE_PLIC
|
|
extern void handle_m_ext_interrupt();
|
|
#endif
|
|
|
|
#ifdef USE_M_TIME
|
|
extern void handle_m_time_interrupt();
|
|
#endif
|
|
|
|
uintptr_t handle_trap(uintptr_t mcause, uintptr_t epc)
|
|
{
|
|
if (0){
|
|
#ifdef USE_PLIC
|
|
// External Machine-Level interrupt from PLIC
|
|
} else if ((mcause & MCAUSE_INT) && ((mcause & MCAUSE_CAUSE) == IRQ_M_EXT)) {
|
|
handle_m_ext_interrupt();
|
|
#endif
|
|
#ifdef USE_M_TIME
|
|
// External Machine-Level interrupt from PLIC
|
|
} else if ((mcause & MCAUSE_INT) && ((mcause & MCAUSE_CAUSE) == IRQ_M_TIMER)){
|
|
handle_m_time_interrupt();
|
|
#endif
|
|
}
|
|
else {
|
|
write(1, "trap\n", 5);
|
|
_exit(1 + mcause);
|
|
}
|
|
return epc;
|
|
}
|
|
|
|
void _init()
|
|
{
|
|
|
|
#ifndef NO_INIT
|
|
init_pll();
|
|
uart_init(115200);
|
|
printf("core freq at %d Hz\n", get_cpu_freq());
|
|
write_csr(mtvec, &trap_entry);
|
|
if (read_csr(misa) & (1 << ('F' - 'A'))) { // if F extension is present
|
|
write_csr(mstatus, MSTATUS_FS); // allow FPU instructions without trapping
|
|
write_csr(fcsr, 0); // initialize rounding mode, undefined at reset
|
|
}
|
|
#endif
|
|
|
|
}
|
|
|
|
void _fini()
|
|
{
|
|
}
|