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GT Block,
Server Base System Architecture (SBSA) Generic Watchdog.
GTDT table structure
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SW Status
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ACPI table defined in UEFI:
typedef struct {
UINT32 Signature;
UINT32 Length;
UINT8 Revision;
UINT8 Checksum;
UINT8 OemId[6];
UINT64 OemTableId;
UINT32 OemRevision;
UINT32 CreatorId;
UINT32 CreatorRevision;
} EFI_ACPI_DESCRIPTION_HEADER;
///
/// Generic Timer Description Table definition.
///
typedef struct {
EFI_ACPI_DESCRIPTION_HEADER Header;
UINT64 PhysicalAddress;
UINT32 GlobalFlags;
UINT32 SecurePL1TimerGSIV;
UINT32 SecurePL1TimerFlags;
UINT32 NonSecurePL1TimerGSIV;
UINT32 NonSecurePL1TimerFlags;
UINT32 VirtualTimerGSIV;
UINT32 VirtualTimerFlags;
UINT32 NonSecurePL2TimerGSIV;
UINT32 NonSecurePL2TimerFlags;
} EFI_ACPI_5_0_GENERIC_TIMER_DESCRIPTION_TABLE;
SW Status
Generic timer work well on i.MX8MP.
Code for ACPI
GTDT table for i.MX8MP:
| Code Block |
|---|
# ARM Architectural Timer Interrupt(GIC PPI) numbers
gArmTokenSpaceGuid.PcdArmArchTimerSecIntrNum|29|UINT32|0x00000035
gArmTokenSpaceGuid.PcdArmArchTimerIntrNum|30|UINT32|0x00000036
gArmTokenSpaceGuid.PcdArmArchTimerHypIntrNum|26|UINT32|0x00000040
gArmTokenSpaceGuid.PcdArmArchTimerVirtIntrNum|27|UINT32|0x00000041
#define GTDT_GLOBAL_FLAGS_MAPPED EFI_ACPI_5_0_GTDT_GLOBAL_FLAG_MEMORY_MAPPED_BLOCK_PRESENT
#define GTDT_GLOBAL_FLAGS_NOT_MAPPED 0
#define GTDT_GLOBAL_FLAGS_EDGE EFI_ACPI_5_0_GTDT_GLOBAL_FLAG_INTERRUPT_MODE
#define GTDT_GLOBAL_FLAGS_LEVEL 0
// Note: We could have a build flag that switches between memory mapped/non-memory mapped timer
#ifdef SYSTEM_TIMER_BASE_ADDRESS
#define GTDT_GLOBAL_FLAGS (GTDT_GLOBAL_FLAGS_MAPPED | GTDT_GLOBAL_FLAGS_LEVEL)
#else
#define GTDT_GLOBAL_FLAGS (GTDT_GLOBAL_FLAGS_NOT_MAPPED | GTDT_GLOBAL_FLAGS_LEVEL)
#define SYSTEM_TIMER_BASE_ADDRESS 0xFFFFFFFFFFFFFFFF
#endif
#define GTDT_TIMER_EDGE_TRIGGERED EFI_ACPI_5_0_GTDT_TIMER_FLAG_TIMER_INTERRUPT_MODE
#define GTDT_TIMER_LEVEL_TRIGGERED 0
#define GTDT_TIMER_ACTIVE_LOW EFI_ACPI_5_0_GTDT_TIMER_FLAG_TIMER_INTERRUPT_POLARITY
#define GTDT_TIMER_ACTIVE_HIGH 0
#define GTDT_GTIMER_FLAGS (GTDT_TIMER_ACTIVE_LOW | GTDT_TIMER_LEVEL_TRIGGERED)
EFI_ACPI_5_0_GENERIC_TIMER_DESCRIPTION_TABLE Gtdt = {
ARM_ACPI_HEADER(
EFI_ACPI_5_0_GENERIC_TIMER_DESCRIPTION_TABLE_SIGNATURE,
EFI_ACPI_5_0_GENERIC_TIMER_DESCRIPTION_TABLE,
EFI_ACPI_5_0_GENERIC_TIMER_DESCRIPTION_TABLE_REVISION
),
SYSTEM_TIMER_BASE_ADDRESS, // UINT64 PhysicalAddress
GTDT_GLOBAL_FLAGS, // UINT32 GlobalFlags
FixedPcdGet32 (PcdArmArchTimerSecIntrNum), // UINT32 SecurePL1TimerGSIV
GTDT_GTIMER_FLAGS, // UINT32 SecurePL1TimerFlags
FixedPcdGet32 (PcdArmArchTimerIntrNum), // UINT32 NonSecurePL1TimerGSIV
GTDT_GTIMER_FLAGS, // UINT32 NonSecurePL1TimerFlags
FixedPcdGet32 (PcdArmArchTimerVirtIntrNum), // UINT32 VirtualTimerGSIV
GTDT_GTIMER_FLAGS, // UINT32 VirtualTimerFlags
FixedPcdGet32 (PcdArmArchTimerHypIntrNum), // UINT32 NonSecurePL2TimerGSIV
GTDT_GTIMER_FLAGS // UINT32 NonSecurePL2TimerFlags
}; |