140 lines
2.8 KiB
C
140 lines
2.8 KiB
C
#include <stdint.h>
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#include <stdio.h>
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#include <unistd.h>
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#include "platform.h"
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#include "encoding.h"
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#if __riscv_xlen == 32
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#define MCAUSE_INT 0x80000000UL
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#define MCAUSE_CAUSE 0x000003FFUL
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#else
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#define MCAUSE_INT 0x8000000000000000UL
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#define MCAUSE_CAUSE 0x00000000000003FFUL
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#endif
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extern int main(int argc, char** argv);
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extern void trap_entry();
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#define IRQ_M_SOFT 3
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#define IRQ_M_TIMER 7
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#define IRQ_M_EXT 11
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#define NUM_INTERRUPTS 16
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#define MTIMER_NEXT_TICK_INC 1000
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void handle_m_ext_interrupt(void);
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void handle_m_time_interrupt(void);
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uint32_t handle_trap(uint32_t mcause, uint32_t mepc, uint32_t sp);
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void default_handler(void);
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void _init(void);
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typedef void (*my_interrupt_function_ptr_t) (void);
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my_interrupt_function_ptr_t localISR[NUM_INTERRUPTS] __attribute__((aligned(64)));
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static unsigned long mtime_lo(void)
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{
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unsigned long ret;
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__asm volatile("rdtime %0":"=r"(ret));
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return ret;
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}
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#if __riscv_xlen==32
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static uint32_t mtime_hi(void)
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{
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unsigned long ret;
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__asm volatile("rdtimeh %0":"=r"(ret));
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return ret;
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}
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uint64_t get_timer_value()
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{
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while (1) {
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uint32_t hi = mtime_hi();
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uint32_t lo = mtime_lo();
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if (hi == mtime_hi())
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return ((uint64_t)hi << 32) | lo;
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}
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}
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#elif __riscv_xlen==64
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uint64_t get_timer_value()
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{
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return mtime_lo();
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}
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#endif
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unsigned long get_timer_freq()
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{
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return 32768;
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}
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unsigned long get_cpu_freq()
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{
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return 100000000;
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}
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void init_pll(void){
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//TODO: implement initialization
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}
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static void uart_init(size_t baud_rate)
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{
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//TODO: implement initialization
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}
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void __attribute__((weak)) handle_m_ext_interrupt(){
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}
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void __attribute__((weak)) handle_m_time_interrupt(){
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uint64_t time = ((uint64_t)mtimer->mtimeh)<<32 || mtimer->mtime;
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time+=MTIMER_NEXT_TICK_INC;
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mtimer->mtimecmph = time>>32;
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mtimer->mtimecmp = time;
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}
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void __attribute__((weak)) default_handler(void) {
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puts("default handler\n");
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}
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uint32_t handle_trap(uint32_t mcause, uint32_t mepc, uint32_t sp){
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if ((mcause & MCAUSE_INT) && ((mcause & MCAUSE_CAUSE) == IRQ_M_EXT)) {
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handle_m_ext_interrupt();
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// External Machine-Level interrupt from PLIC
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} else if ((mcause & MCAUSE_INT) && ((mcause & MCAUSE_CAUSE) == IRQ_M_TIMER)){
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handle_m_time_interrupt();
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} else {
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write(1, "trap\n", 5);
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_exit(1 + mcause);
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}
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return mepc;
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}
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void _init()
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{
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#ifndef NO_INIT
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init_pll();
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uart_init(115200);
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printf("core freq at %d Hz\n", get_cpu_freq());
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write_csr(mtvec, &trap_entry);
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if (read_csr(misa) & (1 << ('F' - 'A'))) { // if F extension is present
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write_csr(mstatus, MSTATUS_FS); // allow FPU instructions without trapping
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write_csr(fcsr, 0); // initialize rounding mode, undefined at reset
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}
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int i=0;
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while(i<NUM_INTERRUPTS) {
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localISR[i++] = default_handler;
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}
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#endif
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}
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void _fini()
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{
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}
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