ACPI 6.0 introduced LPI(Low Power Idle) states that provides an alternate method to describe processor idle states.

LPI extensions leverages the processor container device(again introduced in ACPI 6.0) allowing to express which parts of the system are affected by a given LPI state. It defines the local power states for each node in a hierarchical processor topology. The OSPM can use _LPI object to select a local power state for each level of processor hierarchy in the system.

This patch adds LPI support on Juno.

Contributed-under: TianoCore Contribution Agreement 1.0 Cc: Ard Biesheuvel ard.biesheuvel@linaro.org Cc: Leif Lindholm leif.lindholm@linaro.org Signed-off-by: Sudeep Holla sudeep.holla@arm.com --- Platforms/ARM/Juno/AcpiTables/Dsdt.asl | 232 ++++++++++++++++++++++++++++++--- 1 file changed, 213 insertions(+), 19 deletions(-)

Hi Lief,

The support in the kernel is now added(latest mainline as of today) and is enabled in defconfig. It's easy to test, just examine the sysfs entries:

/sys/devices/system/cpu/cpu*/cpuidle/state*/desc - Describes the cpuidle state /sys/devices/system/cpu/cpu*/cpuidle/state*/{usage,time} - Should keep ticking with time signifying that the idle states are entered and exited correctly

Regards, Sudeep

diff --git a/Platforms/ARM/Juno/AcpiTables/Dsdt.asl b/Platforms/ARM/Juno/AcpiTables/Dsdt.asl index c324ded471f2..07e32bae21f8 100644 --- a/Platforms/ARM/Juno/AcpiTables/Dsdt.asl +++ b/Platforms/ARM/Juno/AcpiTables/Dsdt.asl @@ -19,29 +19,223 @@ DefinitionBlock("DsdtTable.aml", "DSDT", 1, "ARMLTD", "ARM-JUNO", EFI_ACPI_ARM_O // // A57x2-A53x4 Processor declaration // - Device(CPU0) { // A53-0: Cluster 1, Cpu 0 - Name(_HID, "ACPI0007") - Name(_UID, 0) + Method (_OSC, 4, Serialized) { // _OSC: Operating System Capabilities + CreateDWordField (Arg3, 0x00, STS0) + CreateDWordField (Arg3, 0x04, CAP0) + If ((Arg0 == ToUUID ("0811b06e-4a27-44f9-8d60-3cbbc22e7b48") /* Platform-wide Capabilities */)) { + If (!(Arg1 == One)) { + STS0 &= ~0x1F + STS0 |= 0x0A + } Else { + If ((CAP0 & 0x100)) { + CAP0 &= ~0x100 /* No support for OS Initiated LPI */ + STS0 &= ~0x1F + STS0 |= 0x12 + } + } + } Else { + STS0 &= ~0x1F + STS0 |= 0x06 + } + Return (Arg3) } - Device(CPU1) { // A53-1: Cluster 1, Cpu 1 - Name(_HID, "ACPI0007") + Device (CLU0) { // Cluster0 state + Name(_HID, "ACPI0010") Name(_UID, 1) + Name (_LPI, Package() { + 0, // Version + 0, // Level Index + 1, // Count + Package() { // Power Gating state for Cluster + 2500, // Min residency (uS) + 1150, // Wake latency (uS) + 1, // Flags + 1, // Arch Context Flags + 100, //Residency Counter Frequency + 0, // No Parent State + 0x01000000, // Integer Entry method + ResourceTemplate() { // Null Residency Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + ResourceTemplate() { // Null Usage Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + "CluPwrDn" + }, + }) + Name(PLPI, Package() { + 0, // Version + 1, // Level Index + 2, // Count + Package() { // WFI for CPU + 1, // Min residency (uS) + 1, // Wake latency (uS) + 1, // Flags + 0, // Arch Context Flags + 100, //Residency Counter Frequency + 0, // No parent state + ResourceTemplate () { + // Register Entry method + Register (FFixedHW, + 0x20, // Bit Width + 0x00, // Bit Offset + 0xFFFFFFFF, // Address + 0x03, // Access Size + ) + }, + ResourceTemplate() { // Null Residency Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + ResourceTemplate() { // Null Usage Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + "WFI", + }, + Package() { // Power Gating state for CPU + 150, // Min residency (uS) + 350, // Wake latency (uS) + 1, // Flags + 1, // Arch Context Flags + 100, //Residency Counter Frequency + 1, // Parent node can be in any state + ResourceTemplate () { + // Register Entry method + Register (FFixedHW, + 0x20, // Bit Width + 0x00, // Bit Offset + 0x00010000, // Address + 0x03, // Access Size + ) + }, + ResourceTemplate() { // Null Residency Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + ResourceTemplate() { // Null Usage Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + "CorePwrDn" + }, + }) + Device(CPU0) { // A57-0: Cluster 0, Cpu 0 + Name(_HID, "ACPI0007") + Name(_UID, 4) + Method (_LPI, 0, NotSerialized) { + return(PLPI) + } + } + Device(CPU1) { // A57-1: Cluster 0, Cpu 1 + Name(_HID, "ACPI0007") + Name(_UID, 5) + Method (_LPI, 0, NotSerialized) { + return(PLPI) + } + } } - Device(CPU2) { // A53-2: Cluster 1, Cpu 2 - Name(_HID, "ACPI0007") + Device (CLU1) { // Cluster1 state + Name(_HID, "ACPI0010") Name(_UID, 2) - } - Device(CPU3) { // A53-3: Cluster 1, Cpu 3 - Name(_HID, "ACPI0007") - Name(_UID, 3) - } - Device(CPU4) { // A57-0: Cluster 0, Cpu 0 - Name(_HID, "ACPI0007") - Name(_UID, 4) - } - Device(CPU5) { // A57-1: Cluster 0, Cpu 1 - Name(_HID, "ACPI0007") - Name(_UID, 5) + Name (_LPI, Package() { + 0, // Version + 0, // Level Index + 1, // Count + Package() { // Power Gating state for Cluster + 2500, // Min residency (uS) + 1150, // Wake latency (uS) + 1, // Flags + 1, // Arch Context Flags + 100, //Residency Counter Frequency + 0, // No Parent State + 0x01000000, // Integer Entry method + ResourceTemplate() { // Null Residency Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + ResourceTemplate() { // Null Usage Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + "CluPwrDn" + }, + }) + Name(PLPI, Package() { + 0, // Version + 1, // Level Index + 2, // Count + Package() { // WFI for CPU + 1, // Min residency (uS) + 1, // Wake latency (uS) + 1, // Flags + 0, // Arch Context Flags + 100, //Residency Counter Frequency + 0, // No parent state + ResourceTemplate () { + // Register Entry method + Register (FFixedHW, + 0x20, // Bit Width + 0x00, // Bit Offset + 0xFFFFFFFF, // Address + 0x03, // Access Size + ) + }, + ResourceTemplate() { // Null Residency Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + ResourceTemplate() { // Null Usage Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + "WFI", + }, + Package() { // Power Gating state for CPU + 150, // Min residency (uS) + 350, // Wake latency (uS) + 1, // Flags + 1, // Arch Context Flags + 100, //Residency Counter Frequency + 1, // Parent node can be in any state + ResourceTemplate () { + // Register Entry method + Register (FFixedHW, + 0x20, // Bit Width + 0x00, // Bit Offset + 0x00010000, // Address + 0x03, // Access Size + ) + }, + ResourceTemplate() { // Null Residency Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + ResourceTemplate() { // Null Usage Counter + Register (SystemMemory, 0, 0, 0, 0) + }, + "CorePwrDn" + }, + }) + Device(CPU2) { // A53-0: Cluster 1, Cpu 0 + Name(_HID, "ACPI0007") + Name(_UID, 0) + Method (_LPI, 0, NotSerialized) { + return(PLPI) + } + } + Device(CPU3) { // A53-1: Cluster 1, Cpu 1 + Name(_HID, "ACPI0007") + Name(_UID, 1) + Method (_LPI, 0, NotSerialized) { + return(PLPI) + } + } + Device(CPU4) { // A53-2: Cluster 1, Cpu 2 + Name(_HID, "ACPI0007") + Name(_UID, 2) + Method (_LPI, 0, NotSerialized) { + return(PLPI) + } + } + Device(CPU5) { // A53-3: Cluster 1, Cpu 3 + Name(_HID, "ACPI0007") + Name(_UID, 3) + Method (_LPI, 0, NotSerialized) { + return(PLPI) + } + } }

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