90 lines
2.8 KiB
C
90 lines
2.8 KiB
C
/* deshab/tsc.h - TSC 时钟校准与延时
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*
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* 整合 dkm_shared.h 的 dkm_tsc_calibrate/delay_ms/delay_us/serial_wait_tx
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* 与 net_stack.h 的 ns_tsc_calibrate/rdtsc，统一前缀为 dsb_。
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*
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* 用法：
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* dsb_tsc_calibrate() - 在模块入口开头调用，PIT ch0 ~10ms 校准 TSC
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* dsb_rdtsc() - 读取 TSC 时间戳
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* dsb_delay_ms/us() - 基于 TSC 的忙等延时
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* dsb_deadline_reached()- 截止时间判定
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* dsb_serial_wait_tx() - 串口发送就绪等待（100us 超时）
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*
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* 每个 .elf/.drv 包含本头后获得独立 file-local dsb_tsc_per_ms 副本。
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*/
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#ifndef DESHAB_TSC_H
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#define DESHAB_TSC_H
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#include "types.h"
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#include "portio.h"
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static u64 dsb_tsc_per_ms = 0;
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static inline u64 dsb_rdtsc(void) {
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u32 lo, hi;
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__asm__ volatile("rdtsc" : "=a"(lo), "=d"(hi));
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return ((u64)hi << 32) | lo;
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}
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/* PIT ch0 + TSC 校准 ~10ms 区间，推算每毫秒 TSC 周期数。 */
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static inline void dsb_tsc_calibrate(void) {
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if (dsb_tsc_per_ms) return;
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dsb_outb(0x43, 0x30); /* ch0, lo+hi, mode 0, binary */
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dsb_outb(0x40, 0x7C); /* 11932 low = ~10ms */
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dsb_outb(0x40, 0x2E); /* 11932 high */
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u64 tsc_start = dsb_rdtsc();
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u16 prev = 0;
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u64 loops = 0;
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for (;;) {
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dsb_outb(0x43, 0x00);
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u16 cur = (u16)dsb_inb(0x40) | ((u16)dsb_inb(0x40) << 8);
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if (cur > prev && loops > 10) break;
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prev = cur;
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loops++;
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}
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dsb_tsc_per_ms = (dsb_rdtsc() - tsc_start) / 10;
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if (!dsb_tsc_per_ms) dsb_tsc_per_ms = 3000; /* 兜底 ~3GHz */
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}
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static inline int dsb_deadline_reached(u64 deadline) {
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return (i64)(dsb_rdtsc() - deadline) >= 0;
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}
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static inline void dsb_delay_ms(u32 ms) {
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if (!dsb_tsc_per_ms) {
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for (volatile u32 i = 0; i < 100000 * ms; i++) __asm__ volatile("pause");
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return;
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}
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u64 target = dsb_tsc_per_ms * ms;
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u64 start = dsb_rdtsc();
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while (dsb_rdtsc() - start < target) __asm__ volatile("pause");
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}
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static inline void dsb_delay_us(u32 us) {
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if (!dsb_tsc_per_ms) {
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for (volatile u32 i = 0; i < 100 * us; i++) __asm__ volatile("pause");
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return;
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}
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u64 target = dsb_tsc_per_ms * us / 1000;
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u64 start = dsb_rdtsc();
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while (dsb_rdtsc() - start < target) __asm__ volatile("pause");
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}
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/* 串口发送就绪等待（100us 超时）。com_port = 0x3F8 (COM1)。 */
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static inline void dsb_serial_wait_tx(u16 com_port) {
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if (!dsb_tsc_per_ms) {
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for (volatile u32 i = 0; i < 100000; i++) {
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if (dsb_inb((u16)(com_port + 5)) & 0x20) break;
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__asm__ volatile("pause");
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}
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return;
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}
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u64 deadline = dsb_rdtsc() + dsb_tsc_per_ms / 10;
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while (dsb_rdtsc() < deadline) {
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if (dsb_inb((u16)(com_port + 5)) & 0x20) break;
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__asm__ volatile("pause");
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}
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}
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#endif /* DESHAB_TSC_H */
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