55 lines
1.6 KiB
C
55 lines
1.6 KiB
C
#include "clint.h"
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volatile const uint32_t * const mtime_high = (volatile const uint32_t*)(CLINT_BASE + CLINT_MTIME_HIGH);
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volatile const uint32_t * const mtime_low = (volatile const uint32_t*)(CLINT_BASE + CLINT_MTIME_LOW);
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volatile uint32_t * const mtimecmp_high = (volatile const uint32_t*)(CLINT_BASE + CLINT_MTIMECMP_HIGH);
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volatile uint32_t * const mtimecmp_low = (volatile const uint32_t*)(CLINT_BASE + CLINT_MTIMECMP_LOW);
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volatile uint32_t mtimer_int_flag = 0;
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void set_mtimecmp(uint64_t value)
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{
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*mtimecmp_high = 0xFFFFFFFF; // 先写入高 32 位为全 1（禁用中断）
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*mtimecmp_low = (uint32_t)value; // 写入低 32 位
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*mtimecmp_high = (uint32_t)(value >> 32); // 写入高 32 位
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}
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uint64_t read_mtimer()
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{
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uint32_t hi, lo;
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do {
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hi = *mtime_high; // 读取高 32 位
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lo = *mtime_low; // 读取低 32 位
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} while (hi != *mtime_high); // 检查高 32 位是否变化（避免进位）
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return (((uint64_t)hi << 32) | lo);
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}
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void enable_mtimer_int()
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{
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__asm__ volatile ("csrs mie, %0" :: "r"(0x80)); // mie.MTIE = 1
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__asm__ volatile ("csrs mstatus, %0" :: "r"(0x8)); // mstatus.MIE = 1
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}
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void disable_mtimer_int()
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{
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__asm__ volatile ("csrc mie, %0" :: "r"(0x80)); // mie.MTIE = 0
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__asm__ volatile ("csrc mstatus, %0" :: "r"(0x8)); // mstatus.MIE = 0
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}
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void set_mtimer(uint32_t delta_t)
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{
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#if 0
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uint64_t t;
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t = read_mtimer();
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t += delta_t;
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set_mtimecmp(t);
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#else
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uint64_t t;
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t = *(volatile uint64_t *)(CLINT_BASE + CLINT_MTIME_LOW);
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t += delta_t;
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*(volatile uint64_t *)(CLINT_BASE + CLINT_MTIMECMP_LOW) = t;
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#endif
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} |