#ifndef HAZEL_ACPI_H_
#define HAZEL_ACPI_H_

#include <stdint.h>

#define BIOS_START   0x000E0000
#define BIOS_END     0x000FFFFF
#define RSDP_SIG     "RSD PTR "
#define RSDP_SIG_LEN 8
#define RSDP_SIZE    20

struct RSDP {
    char Signature[RSDP_SIG_LEN];
    uint8_t Checksum;
    char OEMID[6];
    uint8_t Revision;
    uint32_t RsdtAddress;
} __attribute__ ((packed));
typedef struct RSDP rsdp_t;

typedef struct {
    char Signature[4];
    uint32_t Length;
    uint8_t Revision;
    uint8_t Checksum;
    char OEMID[6];
    char OEMTableID[8];
    uint32_t OEMRevision;
    uint32_t CreatorID;
    uint32_t CreatorRevision;
} sdt_hdr_t;

typedef struct {
    sdt_hdr_t hdr;
    uint32_t other_tables[];
} rsdt_t;

struct GenericAddressStructure
{
    uint8_t AddressSpace;
    uint8_t BitWidth;
    uint8_t BitOffset;
    uint8_t AccessSize;
    uint64_t Address;
};

struct fadt {
    sdt_hdr_t hdr;
    uint32_t FirmwareCtrl;
    uint32_t Dsdt;
 
    // field used in ACPI 1.0; no longer in use, for compatibility only
    uint8_t  Reserved;
 
    uint8_t  PreferredPowerManagementProfile;
    uint16_t SCI_Interrupt;
    uint32_t SMI_CommandPort;
    uint8_t  AcpiEnable;
    uint8_t  AcpiDisable;
    uint8_t  S4BIOS_REQ;
    uint8_t  PSTATE_Control;
    uint32_t PM1aEventBlock;
    uint32_t PM1bEventBlock;
    uint32_t PM1aControlBlock;
    uint32_t PM1bControlBlock;
    uint32_t PM2ControlBlock;
    uint32_t PMTimerBlock;
    uint32_t GPE0Block;
    uint32_t GPE1Block;
    uint8_t  PM1EventLength;
    uint8_t  PM1ControlLength;
    uint8_t  PM2ControlLength;
    uint8_t  PMTimerLength;
    uint8_t  GPE0Length;
    uint8_t  GPE1Length;
    uint8_t  GPE1Base;
    uint8_t  CStateControl;
    uint16_t WorstC2Latency;
    uint16_t WorstC3Latency;
    uint16_t FlushSize;
    uint16_t FlushStride;
    uint8_t  DutyOffset;
    uint8_t  DutyWidth;
    uint8_t  DayAlarm;
    uint8_t  MonthAlarm;
    uint8_t  Century;
 
    // reserved in ACPI 1.0; used since ACPI 2.0+
    uint16_t BootArchitectureFlags;
 
    uint8_t  Reserved2;
    uint32_t Flags;
 
    // 12 byte structure; see below for details
    struct GenericAddressStructure ResetReg;
 
    uint8_t  ResetValue;
    uint8_t  Reserved3[3];
 
    // 64bit pointers - Available on ACPI 2.0+
    uint64_t                X_FirmwareControl;
    uint64_t                X_Dsdt;
 
    struct GenericAddressStructure X_PM1aEventBlock;
    struct GenericAddressStructure X_PM1bEventBlock;
    struct GenericAddressStructure X_PM1aControlBlock;
    struct GenericAddressStructure X_PM1bControlBlock;
    struct GenericAddressStructure X_PM2ControlBlock;
    struct GenericAddressStructure X_PMTimerBlock;
    struct GenericAddressStructure X_GPE0Block;
    struct GenericAddressStructure X_GPE1Block;
};

rsdp_t *acpi_find_rsdp();
uint32_t acpi_checksum(void *s, int size);
void *acpi_find_sdt(rsdt_t *rsdt, const char sig[6]);

#endif