#ifndef ACPI_H_
#define 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

#define ACPI_VER_1      0
#define ACPI_VER_OTHER  2

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

struct ACPISDTHeader {
  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;
};

struct rsdt {
  struct ACPISDTHeader h;
  uint32_t other_sdt[];
};

struct mcfg_entry {
    uint64_t base_addr;
    uint16_t pci_seg_num;
    uint8_t pci_bus_start;
    uint8_t pci_bus_end;
    uint32_t reserved;
};

struct mcfg {
    struct ACPISDTHeader h;
    uint64_t reserved;
    struct mcfg_entry entries[];
};

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

struct fadt {
    struct   ACPISDTHeader h;
    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;
};

struct rsdp *acpi_locate_rsdp();
int acpi_validate_rsdp_checksum(struct rsdp *s);
int acpi_validate_sdt_checksum(struct ACPISDTHeader *s);
struct ACPISDTHeader *acpi_find_table(struct rsdt *root, const char *signature);
void *acpi_locate_sdt(struct rsdt *rsdt, const char sig[4]);

#endif