kernel: initial hpet support

kernel-src/include/time.h

@@ -0,0 +1,11 @@
+#ifndef _TIME_H
+#define _TIME_H
+
+typedef long time_t;
+
+typedef struct {
+	time_t s;
+	time_t ns;
+} timespec_t;
+
+#endif

kernel-src/include/x86-64/arch/acpi.h

@@ -45,6 +45,24 @@ typedef struct {
 	uint32_t flags;
 } __attribute__((packed)) madt_t;
 
+typedef struct {
+	sdtheader_t header;
+	uint8_t hwrev;
+	uint8_t comparatorcount:5;
+	uint8_t countersize:1;
+	uint8_t reserved:1;
+	uint8_t legacy_replacement:1;
+	uint16_t pcivendor;
+	uint8_t addrid;
+	uint8_t bitwidth;
+	uint8_t bitoffset;
+	uint8_t reserved2;
+	uint64_t addr;
+	uint8_t hpetnum;
+	uint16_t mintick;
+	uint8_t pageprot;
+} __attribute__((packed)) hpet_t;
+
 #define ACPI_MADT_TYPE_LAPIC 0
 #define ACPI_MADT_TYPE_IOAPIC 1
 #define ACPI_MADT_TYPE_OVERRIDE 2

kernel-src/include/x86-64/arch/hpet.h

@@ -0,0 +1,12 @@
+#ifndef _HPET_H
+#define _HPET_h
+
+#include <stdbool.h>
+#include <time.h>
+
+void arch_hpet_waitticks(time_t ticks);
+void arch_hpet_waitus(time_t us);
+bool arch_hpet_exists();
+void arch_hpet_init();
+
+#endif