hpet.h

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#pragma once
 
#include <kernel/acpi/acpi.h>
 
#include <sys/proc.h>
 
typedef enum
{
    HPET_REG_GENERAL_CAPABILITIES_ID = 0x000,
    HPET_REG_GENERAL_CONFIG = 0x010,
    HPET_REG_GENERAL_INTERRUPT = 0x020,
    HPET_REG_MAIN_COUNTER_VALUE = 0x0F0,
    HPET_REG_TIMER0_CONFIG_CAP = 0x100,
    HPET_REG_TIMER0_COMPARATOR = 0x108,
} hpet_register_t;
 
#define HPET_CAP_COUNTER_CLK_PERIOD_SHIFT 32
 
#define HPET_CONF_ENABLE_CNF_BIT (1 << 0)
 
#define HPET_CONF_LEG_RT_CNF_BIT (1 << 1)
 
#define HPET_ADDRESS_SPACE_MEMORY 0
 
#define HPET_ADDRESS_SPACE_IO 1
 
#define HPET_FEMTOSECONDS_PER_SECOND 1000000000000000ULL
 
typedef struct PACKED
{
    sdt_header_t header;
    uint8_t hardwareRevId;
    uint8_t comparatorCount : 5;
    uint8_t counterIs64Bit : 1;
    uint8_t reserved1 : 1;
    uint8_t legacyReplacementCapable : 1;
    uint16_t pciVendorId;
    uint8_t addressSpaceId;
    uint8_t registerBitWidth;
    uint8_t registerBitOffset;
    uint8_t reserved2;
    uint64_t address;
    uint8_t hpetNumber;
    uint16_t minimumTick;
    uint8_t pageProtection;
} hpet_t;
 
clock_t hpet_nanoseconds_per_tick(void);
 
uint64_t hpet_read_counter(void);
 
void hpet_reset_counter(void);
 
void hpet_write(uint64_t reg, uint64_t value);
 
uint64_t hpet_read(uint64_t reg);
 
void hpet_wait(clock_t nanoseconds);