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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/devicetree/bindings/cpu
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
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Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to 'Documentation/devicetree/bindings/cpu')
-rw-r--r--Documentation/devicetree/bindings/cpu/cpu-topology.txt553
-rw-r--r--Documentation/devicetree/bindings/cpu/idle-states.yaml855
2 files changed, 1408 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/cpu/cpu-topology.txt b/Documentation/devicetree/bindings/cpu/cpu-topology.txt
new file mode 100644
index 000000000..9bd530a35
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpu/cpu-topology.txt
@@ -0,0 +1,553 @@
+===========================================
+CPU topology binding description
+===========================================
+
+===========================================
+1 - Introduction
+===========================================
+
+In a SMP system, the hierarchy of CPUs is defined through three entities that
+are used to describe the layout of physical CPUs in the system:
+
+- socket
+- cluster
+- core
+- thread
+
+The bottom hierarchy level sits at core or thread level depending on whether
+symmetric multi-threading (SMT) is supported or not.
+
+For instance in a system where CPUs support SMT, "cpu" nodes represent all
+threads existing in the system and map to the hierarchy level "thread" above.
+In systems where SMT is not supported "cpu" nodes represent all cores present
+in the system and map to the hierarchy level "core" above.
+
+CPU topology bindings allow one to associate cpu nodes with hierarchical groups
+corresponding to the system hierarchy; syntactically they are defined as device
+tree nodes.
+
+Currently, only ARM/RISC-V intend to use this cpu topology binding but it may be
+used for any other architecture as well.
+
+The cpu nodes, as per bindings defined in [4], represent the devices that
+correspond to physical CPUs and are to be mapped to the hierarchy levels.
+
+A topology description containing phandles to cpu nodes that are not compliant
+with bindings standardized in [4] is therefore considered invalid.
+
+===========================================
+2 - cpu-map node
+===========================================
+
+The ARM/RISC-V CPU topology is defined within the cpu-map node, which is a direct
+child of the cpus node and provides a container where the actual topology
+nodes are listed.
+
+- cpu-map node
+
+ Usage: Optional - On SMP systems provide CPUs topology to the OS.
+ Uniprocessor systems do not require a topology
+ description and therefore should not define a
+ cpu-map node.
+
+ Description: The cpu-map node is just a container node where its
+ subnodes describe the CPU topology.
+
+ Node name must be "cpu-map".
+
+ The cpu-map node's parent node must be the cpus node.
+
+ The cpu-map node's child nodes can be:
+
+ - one or more cluster nodes or
+ - one or more socket nodes in a multi-socket system
+
+ Any other configuration is considered invalid.
+
+The cpu-map node can only contain 4 types of child nodes:
+
+- socket node
+- cluster node
+- core node
+- thread node
+
+whose bindings are described in paragraph 3.
+
+The nodes describing the CPU topology (socket/cluster/core/thread) can
+only be defined within the cpu-map node and every core/thread in the
+system must be defined within the topology. Any other configuration is
+invalid and therefore must be ignored.
+
+===========================================
+2.1 - cpu-map child nodes naming convention
+===========================================
+
+cpu-map child nodes must follow a naming convention where the node name
+must be "socketN", "clusterN", "coreN", "threadN" depending on the node type
+(ie socket/cluster/core/thread) (where N = {0, 1, ...} is the node number; nodes
+which are siblings within a single common parent node must be given a unique and
+sequential N value, starting from 0).
+cpu-map child nodes which do not share a common parent node can have the same
+name (ie same number N as other cpu-map child nodes at different device tree
+levels) since name uniqueness will be guaranteed by the device tree hierarchy.
+
+===========================================
+3 - socket/cluster/core/thread node bindings
+===========================================
+
+Bindings for socket/cluster/cpu/thread nodes are defined as follows:
+
+- socket node
+
+ Description: must be declared within a cpu-map node, one node
+ per physical socket in the system. A system can
+ contain single or multiple physical socket.
+ The association of sockets and NUMA nodes is beyond
+ the scope of this bindings, please refer [2] for
+ NUMA bindings.
+
+ This node is optional for a single socket system.
+
+ The socket node name must be "socketN" as described in 2.1 above.
+ A socket node can not be a leaf node.
+
+ A socket node's child nodes must be one or more cluster nodes.
+
+ Any other configuration is considered invalid.
+
+- cluster node
+
+ Description: must be declared within a cpu-map node, one node
+ per cluster. A system can contain several layers of
+ clustering within a single physical socket and cluster
+ nodes can be contained in parent cluster nodes.
+
+ The cluster node name must be "clusterN" as described in 2.1 above.
+ A cluster node can not be a leaf node.
+
+ A cluster node's child nodes must be:
+
+ - one or more cluster nodes; or
+ - one or more core nodes
+
+ Any other configuration is considered invalid.
+
+- core node
+
+ Description: must be declared in a cluster node, one node per core in
+ the cluster. If the system does not support SMT, core
+ nodes are leaf nodes, otherwise they become containers of
+ thread nodes.
+
+ The core node name must be "coreN" as described in 2.1 above.
+
+ A core node must be a leaf node if SMT is not supported.
+
+ Properties for core nodes that are leaf nodes:
+
+ - cpu
+ Usage: required
+ Value type: <phandle>
+ Definition: a phandle to the cpu node that corresponds to the
+ core node.
+
+ If a core node is not a leaf node (CPUs supporting SMT) a core node's
+ child nodes can be:
+
+ - one or more thread nodes
+
+ Any other configuration is considered invalid.
+
+- thread node
+
+ Description: must be declared in a core node, one node per thread
+ in the core if the system supports SMT. Thread nodes are
+ always leaf nodes in the device tree.
+
+ The thread node name must be "threadN" as described in 2.1 above.
+
+ A thread node must be a leaf node.
+
+ A thread node must contain the following property:
+
+ - cpu
+ Usage: required
+ Value type: <phandle>
+ Definition: a phandle to the cpu node that corresponds to
+ the thread node.
+
+===========================================
+4 - Example dts
+===========================================
+
+Example 1 (ARM 64-bit, 16-cpu system, two clusters of clusters in a single
+physical socket):
+
+cpus {
+ #size-cells = <0>;
+ #address-cells = <2>;
+
+ cpu-map {
+ socket0 {
+ cluster0 {
+ cluster0 {
+ core0 {
+ thread0 {
+ cpu = <&CPU0>;
+ };
+ thread1 {
+ cpu = <&CPU1>;
+ };
+ };
+
+ core1 {
+ thread0 {
+ cpu = <&CPU2>;
+ };
+ thread1 {
+ cpu = <&CPU3>;
+ };
+ };
+ };
+
+ cluster1 {
+ core0 {
+ thread0 {
+ cpu = <&CPU4>;
+ };
+ thread1 {
+ cpu = <&CPU5>;
+ };
+ };
+
+ core1 {
+ thread0 {
+ cpu = <&CPU6>;
+ };
+ thread1 {
+ cpu = <&CPU7>;
+ };
+ };
+ };
+ };
+
+ cluster1 {
+ cluster0 {
+ core0 {
+ thread0 {
+ cpu = <&CPU8>;
+ };
+ thread1 {
+ cpu = <&CPU9>;
+ };
+ };
+ core1 {
+ thread0 {
+ cpu = <&CPU10>;
+ };
+ thread1 {
+ cpu = <&CPU11>;
+ };
+ };
+ };
+
+ cluster1 {
+ core0 {
+ thread0 {
+ cpu = <&CPU12>;
+ };
+ thread1 {
+ cpu = <&CPU13>;
+ };
+ };
+ core1 {
+ thread0 {
+ cpu = <&CPU14>;
+ };
+ thread1 {
+ cpu = <&CPU15>;
+ };
+ };
+ };
+ };
+ };
+ };
+
+ CPU0: cpu@0 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x0>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU1: cpu@1 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x1>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU2: cpu@100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x100>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU3: cpu@101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x101>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU4: cpu@10000 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x10000>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU5: cpu@10001 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x10001>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU6: cpu@10100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x10100>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU7: cpu@10101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x10101>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU8: cpu@100000000 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x1 0x0>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU9: cpu@100000001 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x1 0x1>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU10: cpu@100000100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x1 0x100>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU11: cpu@100000101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x1 0x101>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU12: cpu@100010000 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x1 0x10000>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU13: cpu@100010001 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x1 0x10001>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU14: cpu@100010100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x1 0x10100>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU15: cpu@100010101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x1 0x10101>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+};
+
+Example 2 (ARM 32-bit, dual-cluster, 8-cpu system, no SMT):
+
+cpus {
+ #size-cells = <0>;
+ #address-cells = <1>;
+
+ cpu-map {
+ cluster0 {
+ core0 {
+ cpu = <&CPU0>;
+ };
+ core1 {
+ cpu = <&CPU1>;
+ };
+ core2 {
+ cpu = <&CPU2>;
+ };
+ core3 {
+ cpu = <&CPU3>;
+ };
+ };
+
+ cluster1 {
+ core0 {
+ cpu = <&CPU4>;
+ };
+ core1 {
+ cpu = <&CPU5>;
+ };
+ core2 {
+ cpu = <&CPU6>;
+ };
+ core3 {
+ cpu = <&CPU7>;
+ };
+ };
+ };
+
+ CPU0: cpu@0 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a15";
+ reg = <0x0>;
+ };
+
+ CPU1: cpu@1 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a15";
+ reg = <0x1>;
+ };
+
+ CPU2: cpu@2 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a15";
+ reg = <0x2>;
+ };
+
+ CPU3: cpu@3 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a15";
+ reg = <0x3>;
+ };
+
+ CPU4: cpu@100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a7";
+ reg = <0x100>;
+ };
+
+ CPU5: cpu@101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a7";
+ reg = <0x101>;
+ };
+
+ CPU6: cpu@102 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a7";
+ reg = <0x102>;
+ };
+
+ CPU7: cpu@103 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a7";
+ reg = <0x103>;
+ };
+};
+
+Example 3: HiFive Unleashed (RISC-V 64 bit, 4 core system)
+
+{
+ #address-cells = <2>;
+ #size-cells = <2>;
+ compatible = "sifive,fu540g", "sifive,fu500";
+ model = "sifive,hifive-unleashed-a00";
+
+ ...
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ cpu-map {
+ socket0 {
+ cluster0 {
+ core0 {
+ cpu = <&CPU1>;
+ };
+ core1 {
+ cpu = <&CPU2>;
+ };
+ core2 {
+ cpu0 = <&CPU2>;
+ };
+ core3 {
+ cpu0 = <&CPU3>;
+ };
+ };
+ };
+ };
+
+ CPU1: cpu@1 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x1>;
+ }
+
+ CPU2: cpu@2 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x2>;
+ }
+ CPU3: cpu@3 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x3>;
+ }
+ CPU4: cpu@4 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x4>;
+ }
+ }
+};
+===============================================================================
+[1] ARM Linux kernel documentation
+ Documentation/devicetree/bindings/arm/cpus.yaml
+[2] Devicetree NUMA binding description
+ Documentation/devicetree/bindings/numa.txt
+[3] RISC-V Linux kernel documentation
+ Documentation/devicetree/bindings/riscv/cpus.yaml
+[4] https://www.devicetree.org/specifications/
diff --git a/Documentation/devicetree/bindings/cpu/idle-states.yaml b/Documentation/devicetree/bindings/cpu/idle-states.yaml
new file mode 100644
index 000000000..b8cc826c9
--- /dev/null
+++ b/Documentation/devicetree/bindings/cpu/idle-states.yaml
@@ -0,0 +1,855 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/cpu/idle-states.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Idle states
+
+maintainers:
+ - Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
+ - Anup Patel <anup@brainfault.org>
+
+description: |+
+ ==========================================
+ 1 - Introduction
+ ==========================================
+
+ ARM and RISC-V systems contain HW capable of managing power consumption
+ dynamically, where cores can be put in different low-power states (ranging
+ from simple wfi to power gating) according to OS PM policies. The CPU states
+ representing the range of dynamic idle states that a processor can enter at
+ run-time, can be specified through device tree bindings representing the
+ parameters required to enter/exit specific idle states on a given processor.
+
+ ==========================================
+ 2 - ARM idle states
+ ==========================================
+
+ According to the Server Base System Architecture document (SBSA, [3]), the
+ power states an ARM CPU can be put into are identified by the following list:
+
+ - Running
+ - Idle_standby
+ - Idle_retention
+ - Sleep
+ - Off
+
+ The power states described in the SBSA document define the basic CPU states on
+ top of which ARM platforms implement power management schemes that allow an OS
+ PM implementation to put the processor in different idle states (which include
+ states listed above; "off" state is not an idle state since it does not have
+ wake-up capabilities, hence it is not considered in this document).
+
+ Idle state parameters (e.g. entry latency) are platform specific and need to
+ be characterized with bindings that provide the required information to OS PM
+ code so that it can build the required tables and use them at runtime.
+
+ The device tree binding definition for ARM idle states is the subject of this
+ document.
+
+ ==========================================
+ 3 - RISC-V idle states
+ ==========================================
+
+ On RISC-V systems, the HARTs (or CPUs) [6] can be put in platform specific
+ suspend (or idle) states (ranging from simple WFI, power gating, etc). The
+ RISC-V SBI v0.3 (or higher) [7] hart state management extension provides a
+ standard mechanism for OS to request HART state transitions.
+
+ The platform specific suspend (or idle) states of a hart can be either
+ retentive or non-rententive in nature. A retentive suspend state will
+ preserve HART registers and CSR values for all privilege modes whereas
+ a non-retentive suspend state will not preserve HART registers and CSR
+ values.
+
+ ===========================================
+ 4 - idle-states definitions
+ ===========================================
+
+ Idle states are characterized for a specific system through a set of
+ timing and energy related properties, that underline the HW behaviour
+ triggered upon idle states entry and exit.
+
+ The following diagram depicts the CPU execution phases and related timing
+ properties required to enter and exit an idle state:
+
+ ..__[EXEC]__|__[PREP]__|__[ENTRY]__|__[IDLE]__|__[EXIT]__|__[EXEC]__..
+ | | | | |
+
+ |<------ entry ------->|
+ | latency |
+ |<- exit ->|
+ | latency |
+ |<-------- min-residency -------->|
+ |<------- wakeup-latency ------->|
+
+ Diagram 1: CPU idle state execution phases
+
+ EXEC: Normal CPU execution.
+
+ PREP: Preparation phase before committing the hardware to idle mode
+ like cache flushing. This is abortable on pending wake-up
+ event conditions. The abort latency is assumed to be negligible
+ (i.e. less than the ENTRY + EXIT duration). If aborted, CPU
+ goes back to EXEC. This phase is optional. If not abortable,
+ this should be included in the ENTRY phase instead.
+
+ ENTRY: The hardware is committed to idle mode. This period must run
+ to completion up to IDLE before anything else can happen.
+
+ IDLE: This is the actual energy-saving idle period. This may last
+ between 0 and infinite time, until a wake-up event occurs.
+
+ EXIT: Period during which the CPU is brought back to operational
+ mode (EXEC).
+
+ entry-latency: Worst case latency required to enter the idle state. The
+ exit-latency may be guaranteed only after entry-latency has passed.
+
+ min-residency: Minimum period, including preparation and entry, for a given
+ idle state to be worthwhile energywise.
+
+ wakeup-latency: Maximum delay between the signaling of a wake-up event and the
+ CPU being able to execute normal code again. If not specified, this is assumed
+ to be entry-latency + exit-latency.
+
+ These timing parameters can be used by an OS in different circumstances.
+
+ An idle CPU requires the expected min-residency time to select the most
+ appropriate idle state based on the expected expiry time of the next IRQ
+ (i.e. wake-up) that causes the CPU to return to the EXEC phase.
+
+ An operating system scheduler may need to compute the shortest wake-up delay
+ for CPUs in the system by detecting how long will it take to get a CPU out
+ of an idle state, e.g.:
+
+ wakeup-delay = exit-latency + max(entry-latency - (now - entry-timestamp), 0)
+
+ In other words, the scheduler can make its scheduling decision by selecting
+ (e.g. waking-up) the CPU with the shortest wake-up delay.
+ The wake-up delay must take into account the entry latency if that period
+ has not expired. The abortable nature of the PREP period can be ignored
+ if it cannot be relied upon (e.g. the PREP deadline may occur much sooner than
+ the worst case since it depends on the CPU operating conditions, i.e. caches
+ state).
+
+ An OS has to reliably probe the wakeup-latency since some devices can enforce
+ latency constraint guarantees to work properly, so the OS has to detect the
+ worst case wake-up latency it can incur if a CPU is allowed to enter an
+ idle state, and possibly to prevent that to guarantee reliable device
+ functioning.
+
+ The min-residency time parameter deserves further explanation since it is
+ expressed in time units but must factor in energy consumption coefficients.
+
+ The energy consumption of a cpu when it enters a power state can be roughly
+ characterised by the following graph:
+
+ |
+ |
+ |
+ e |
+ n | /---
+ e | /------
+ r | /------
+ g | /-----
+ y | /------
+ | ----
+ | /|
+ | / |
+ | / |
+ | / |
+ | / |
+ | / |
+ |/ |
+ -----|-------+----------------------------------
+ 0| 1 time(ms)
+
+ Graph 1: Energy vs time example
+
+ The graph is split in two parts delimited by time 1ms on the X-axis.
+ The graph curve with X-axis values = { x | 0 < x < 1ms } has a steep slope
+ and denotes the energy costs incurred while entering and leaving the idle
+ state.
+ The graph curve in the area delimited by X-axis values = {x | x > 1ms } has
+ shallower slope and essentially represents the energy consumption of the idle
+ state.
+
+ min-residency is defined for a given idle state as the minimum expected
+ residency time for a state (inclusive of preparation and entry) after
+ which choosing that state become the most energy efficient option. A good
+ way to visualise this, is by taking the same graph above and comparing some
+ states energy consumptions plots.
+
+ For sake of simplicity, let's consider a system with two idle states IDLE1,
+ and IDLE2:
+
+ |
+ |
+ |
+ | /-- IDLE1
+ e | /---
+ n | /----
+ e | /---
+ r | /-----/--------- IDLE2
+ g | /-------/---------
+ y | ------------ /---|
+ | / /---- |
+ | / /--- |
+ | / /---- |
+ | / /--- |
+ | --- |
+ | / |
+ | / |
+ |/ | time
+ ---/----------------------------+------------------------
+ |IDLE1-energy < IDLE2-energy | IDLE2-energy < IDLE1-energy
+ |
+ IDLE2-min-residency
+
+ Graph 2: idle states min-residency example
+
+ In graph 2 above, that takes into account idle states entry/exit energy
+ costs, it is clear that if the idle state residency time (i.e. time till next
+ wake-up IRQ) is less than IDLE2-min-residency, IDLE1 is the better idle state
+ choice energywise.
+
+ This is mainly down to the fact that IDLE1 entry/exit energy costs are lower
+ than IDLE2.
+
+ However, the lower power consumption (i.e. shallower energy curve slope) of
+ idle state IDLE2 implies that after a suitable time, IDLE2 becomes more energy
+ efficient.
+
+ The time at which IDLE2 becomes more energy efficient than IDLE1 (and other
+ shallower states in a system with multiple idle states) is defined
+ IDLE2-min-residency and corresponds to the time when energy consumption of
+ IDLE1 and IDLE2 states breaks even.
+
+ The definitions provided in this section underpin the idle states
+ properties specification that is the subject of the following sections.
+
+ ===========================================
+ 5 - idle-states node
+ ===========================================
+
+ The processor idle states are defined within the idle-states node, which is
+ a direct child of the cpus node [1] and provides a container where the
+ processor idle states, defined as device tree nodes, are listed.
+
+ On ARM systems, it is a container of processor idle states nodes. If the
+ system does not provide CPU power management capabilities, or the processor
+ just supports idle_standby, an idle-states node is not required.
+
+ ===========================================
+ 6 - References
+ ===========================================
+
+ [1] ARM Linux Kernel documentation - CPUs bindings
+ Documentation/devicetree/bindings/arm/cpus.yaml
+
+ [2] ARM Linux Kernel documentation - PSCI bindings
+ Documentation/devicetree/bindings/arm/psci.yaml
+
+ [3] ARM Server Base System Architecture (SBSA)
+ http://infocenter.arm.com/help/index.jsp
+
+ [4] ARM Architecture Reference Manuals
+ http://infocenter.arm.com/help/index.jsp
+
+ [5] ARM Linux Kernel documentation - Booting AArch64 Linux
+ Documentation/arm64/booting.rst
+
+ [6] RISC-V Linux Kernel documentation - CPUs bindings
+ Documentation/devicetree/bindings/riscv/cpus.yaml
+
+ [7] RISC-V Supervisor Binary Interface (SBI)
+ http://github.com/riscv/riscv-sbi-doc/riscv-sbi.adoc
+
+properties:
+ $nodename:
+ const: idle-states
+
+ entry-method:
+ description: |
+ Usage and definition depend on ARM architecture version.
+
+ On ARM v8 64-bit this property is required.
+ On ARM 32-bit systems this property is optional
+
+ This assumes that the "enable-method" property is set to "psci" in the cpu
+ node[5] that is responsible for setting up CPU idle management in the OS
+ implementation.
+ const: psci
+
+patternProperties:
+ "^(cpu|cluster)-":
+ type: object
+ description: |
+ Each state node represents an idle state description and must be defined
+ as follows.
+
+ The idle state entered by executing the wfi instruction (idle_standby
+ SBSA,[3][4]) is considered standard on all ARM and RISC-V platforms and
+ therefore must not be listed.
+
+ In addition to the properties listed above, a state node may require
+ additional properties specific to the entry-method defined in the
+ idle-states node. Please refer to the entry-method bindings
+ documentation for properties definitions.
+
+ properties:
+ compatible:
+ enum:
+ - arm,idle-state
+ - riscv,idle-state
+
+ arm,psci-suspend-param:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: |
+ power_state parameter to pass to the ARM PSCI suspend call.
+
+ Device tree nodes that require usage of PSCI CPU_SUSPEND function
+ (i.e. idle states node with entry-method property is set to "psci")
+ must specify this property.
+
+ riscv,sbi-suspend-param:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: |
+ suspend_type parameter to pass to the RISC-V SBI HSM suspend call.
+
+ This property is required in idle state nodes of device tree meant
+ for RISC-V systems. For more details on the suspend_type parameter
+ refer the SBI specifiation v0.3 (or higher) [7].
+
+ local-timer-stop:
+ description:
+ If present the CPU local timer control logic is
+ lost on state entry, otherwise it is retained.
+ type: boolean
+
+ entry-latency-us:
+ description:
+ Worst case latency in microseconds required to enter the idle state.
+
+ exit-latency-us:
+ description:
+ Worst case latency in microseconds required to exit the idle state.
+ The exit-latency-us duration may be guaranteed only after
+ entry-latency-us has passed.
+
+ min-residency-us:
+ description:
+ Minimum residency duration in microseconds, inclusive of preparation
+ and entry, for this idle state to be considered worthwhile energy wise
+ (refer to section 2 of this document for a complete description).
+
+ wakeup-latency-us:
+ description: |
+ Maximum delay between the signaling of a wake-up event and the CPU
+ being able to execute normal code again. If omitted, this is assumed
+ to be equal to:
+
+ entry-latency-us + exit-latency-us
+
+ It is important to supply this value on systems where the duration of
+ PREP phase (see diagram 1, section 2) is non-neglibigle. In such
+ systems entry-latency-us + exit-latency-us will exceed
+ wakeup-latency-us by this duration.
+
+ idle-state-name:
+ $ref: /schemas/types.yaml#/definitions/string
+ description:
+ A string used as a descriptive name for the idle state.
+
+ additionalProperties: false
+
+ required:
+ - compatible
+ - entry-latency-us
+ - exit-latency-us
+ - min-residency-us
+
+additionalProperties: false
+
+examples:
+ - |
+
+ cpus {
+ #size-cells = <0>;
+ #address-cells = <2>;
+
+ cpu@0 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x0>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
+ <&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
+ };
+
+ cpu@1 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x1>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
+ <&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
+ };
+
+ cpu@100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x100>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
+ <&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
+ };
+
+ cpu@101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x101>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
+ <&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
+ };
+
+ cpu@10000 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x10000>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
+ <&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
+ };
+
+ cpu@10001 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x10001>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
+ <&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
+ };
+
+ cpu@10100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x10100>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
+ <&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
+ };
+
+ cpu@10101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a57";
+ reg = <0x0 0x10101>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_0_0>, <&CPU_SLEEP_0_0>,
+ <&CLUSTER_RETENTION_0>, <&CLUSTER_SLEEP_0>;
+ };
+
+ cpu@100000000 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a53";
+ reg = <0x1 0x0>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
+ <&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
+ };
+
+ cpu@100000001 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a53";
+ reg = <0x1 0x1>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
+ <&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
+ };
+
+ cpu@100000100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a53";
+ reg = <0x1 0x100>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
+ <&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
+ };
+
+ cpu@100000101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a53";
+ reg = <0x1 0x101>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
+ <&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
+ };
+
+ cpu@100010000 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a53";
+ reg = <0x1 0x10000>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
+ <&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
+ };
+
+ cpu@100010001 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a53";
+ reg = <0x1 0x10001>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
+ <&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
+ };
+
+ cpu@100010100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a53";
+ reg = <0x1 0x10100>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
+ <&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
+ };
+
+ cpu@100010101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a53";
+ reg = <0x1 0x10101>;
+ enable-method = "psci";
+ cpu-idle-states = <&CPU_RETENTION_1_0>, <&CPU_SLEEP_1_0>,
+ <&CLUSTER_RETENTION_1>, <&CLUSTER_SLEEP_1>;
+ };
+
+ idle-states {
+ entry-method = "psci";
+
+ CPU_RETENTION_0_0: cpu-retention-0-0 {
+ compatible = "arm,idle-state";
+ arm,psci-suspend-param = <0x0010000>;
+ entry-latency-us = <20>;
+ exit-latency-us = <40>;
+ min-residency-us = <80>;
+ };
+
+ CLUSTER_RETENTION_0: cluster-retention-0 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ arm,psci-suspend-param = <0x1010000>;
+ entry-latency-us = <50>;
+ exit-latency-us = <100>;
+ min-residency-us = <250>;
+ wakeup-latency-us = <130>;
+ };
+
+ CPU_SLEEP_0_0: cpu-sleep-0-0 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ arm,psci-suspend-param = <0x0010000>;
+ entry-latency-us = <250>;
+ exit-latency-us = <500>;
+ min-residency-us = <950>;
+ };
+
+ CLUSTER_SLEEP_0: cluster-sleep-0 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ arm,psci-suspend-param = <0x1010000>;
+ entry-latency-us = <600>;
+ exit-latency-us = <1100>;
+ min-residency-us = <2700>;
+ wakeup-latency-us = <1500>;
+ };
+
+ CPU_RETENTION_1_0: cpu-retention-1-0 {
+ compatible = "arm,idle-state";
+ arm,psci-suspend-param = <0x0010000>;
+ entry-latency-us = <20>;
+ exit-latency-us = <40>;
+ min-residency-us = <90>;
+ };
+
+ CLUSTER_RETENTION_1: cluster-retention-1 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ arm,psci-suspend-param = <0x1010000>;
+ entry-latency-us = <50>;
+ exit-latency-us = <100>;
+ min-residency-us = <270>;
+ wakeup-latency-us = <100>;
+ };
+
+ CPU_SLEEP_1_0: cpu-sleep-1-0 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ arm,psci-suspend-param = <0x0010000>;
+ entry-latency-us = <70>;
+ exit-latency-us = <100>;
+ min-residency-us = <300>;
+ wakeup-latency-us = <150>;
+ };
+
+ CLUSTER_SLEEP_1: cluster-sleep-1 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ arm,psci-suspend-param = <0x1010000>;
+ entry-latency-us = <500>;
+ exit-latency-us = <1200>;
+ min-residency-us = <3500>;
+ wakeup-latency-us = <1300>;
+ };
+ };
+ };
+
+ - |
+ // Example 2 (ARM 32-bit, 8-cpu system, two clusters):
+
+ cpus {
+ #size-cells = <0>;
+ #address-cells = <1>;
+
+ cpu@0 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a15";
+ reg = <0x0>;
+ cpu-idle-states = <&cpu_sleep_0_0>, <&cluster_sleep_0>;
+ };
+
+ cpu@1 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a15";
+ reg = <0x1>;
+ cpu-idle-states = <&cpu_sleep_0_0>, <&cluster_sleep_0>;
+ };
+
+ cpu@2 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a15";
+ reg = <0x2>;
+ cpu-idle-states = <&cpu_sleep_0_0>, <&cluster_sleep_0>;
+ };
+
+ cpu@3 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a15";
+ reg = <0x3>;
+ cpu-idle-states = <&cpu_sleep_0_0>, <&cluster_sleep_0>;
+ };
+
+ cpu@100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a7";
+ reg = <0x100>;
+ cpu-idle-states = <&cpu_sleep_1_0>, <&cluster_sleep_1>;
+ };
+
+ cpu@101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a7";
+ reg = <0x101>;
+ cpu-idle-states = <&cpu_sleep_1_0>, <&cluster_sleep_1>;
+ };
+
+ cpu@102 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a7";
+ reg = <0x102>;
+ cpu-idle-states = <&cpu_sleep_1_0>, <&cluster_sleep_1>;
+ };
+
+ cpu@103 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a7";
+ reg = <0x103>;
+ cpu-idle-states = <&cpu_sleep_1_0>, <&cluster_sleep_1>;
+ };
+
+ idle-states {
+ cpu_sleep_0_0: cpu-sleep-0-0 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ entry-latency-us = <200>;
+ exit-latency-us = <100>;
+ min-residency-us = <400>;
+ wakeup-latency-us = <250>;
+ };
+
+ cluster_sleep_0: cluster-sleep-0 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ entry-latency-us = <500>;
+ exit-latency-us = <1500>;
+ min-residency-us = <2500>;
+ wakeup-latency-us = <1700>;
+ };
+
+ cpu_sleep_1_0: cpu-sleep-1-0 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ entry-latency-us = <300>;
+ exit-latency-us = <500>;
+ min-residency-us = <900>;
+ wakeup-latency-us = <600>;
+ };
+
+ cluster_sleep_1: cluster-sleep-1 {
+ compatible = "arm,idle-state";
+ local-timer-stop;
+ entry-latency-us = <800>;
+ exit-latency-us = <2000>;
+ min-residency-us = <6500>;
+ wakeup-latency-us = <2300>;
+ };
+ };
+ };
+
+ - |
+ // Example 3 (RISC-V 64-bit, 4-cpu systems, two clusters):
+
+ cpus {
+ #size-cells = <0>;
+ #address-cells = <1>;
+
+ cpu@0 {
+ device_type = "cpu";
+ compatible = "riscv";
+ reg = <0x0>;
+ riscv,isa = "rv64imafdc";
+ mmu-type = "riscv,sv48";
+ cpu-idle-states = <&CPU_RET_0_0>, <&CPU_NONRET_0_0>,
+ <&CLUSTER_RET_0>, <&CLUSTER_NONRET_0>;
+
+ cpu_intc0: interrupt-controller {
+ #interrupt-cells = <1>;
+ compatible = "riscv,cpu-intc";
+ interrupt-controller;
+ };
+ };
+
+ cpu@1 {
+ device_type = "cpu";
+ compatible = "riscv";
+ reg = <0x1>;
+ riscv,isa = "rv64imafdc";
+ mmu-type = "riscv,sv48";
+ cpu-idle-states = <&CPU_RET_0_0>, <&CPU_NONRET_0_0>,
+ <&CLUSTER_RET_0>, <&CLUSTER_NONRET_0>;
+
+ cpu_intc1: interrupt-controller {
+ #interrupt-cells = <1>;
+ compatible = "riscv,cpu-intc";
+ interrupt-controller;
+ };
+ };
+
+ cpu@10 {
+ device_type = "cpu";
+ compatible = "riscv";
+ reg = <0x10>;
+ riscv,isa = "rv64imafdc";
+ mmu-type = "riscv,sv48";
+ cpu-idle-states = <&CPU_RET_1_0>, <&CPU_NONRET_1_0>,
+ <&CLUSTER_RET_1>, <&CLUSTER_NONRET_1>;
+
+ cpu_intc10: interrupt-controller {
+ #interrupt-cells = <1>;
+ compatible = "riscv,cpu-intc";
+ interrupt-controller;
+ };
+ };
+
+ cpu@11 {
+ device_type = "cpu";
+ compatible = "riscv";
+ reg = <0x11>;
+ riscv,isa = "rv64imafdc";
+ mmu-type = "riscv,sv48";
+ cpu-idle-states = <&CPU_RET_1_0>, <&CPU_NONRET_1_0>,
+ <&CLUSTER_RET_1>, <&CLUSTER_NONRET_1>;
+
+ cpu_intc11: interrupt-controller {
+ #interrupt-cells = <1>;
+ compatible = "riscv,cpu-intc";
+ interrupt-controller;
+ };
+ };
+
+ idle-states {
+ CPU_RET_0_0: cpu-retentive-0-0 {
+ compatible = "riscv,idle-state";
+ riscv,sbi-suspend-param = <0x10000000>;
+ entry-latency-us = <20>;
+ exit-latency-us = <40>;
+ min-residency-us = <80>;
+ };
+
+ CPU_NONRET_0_0: cpu-nonretentive-0-0 {
+ compatible = "riscv,idle-state";
+ riscv,sbi-suspend-param = <0x90000000>;
+ entry-latency-us = <250>;
+ exit-latency-us = <500>;
+ min-residency-us = <950>;
+ };
+
+ CLUSTER_RET_0: cluster-retentive-0 {
+ compatible = "riscv,idle-state";
+ riscv,sbi-suspend-param = <0x11000000>;
+ local-timer-stop;
+ entry-latency-us = <50>;
+ exit-latency-us = <100>;
+ min-residency-us = <250>;
+ wakeup-latency-us = <130>;
+ };
+
+ CLUSTER_NONRET_0: cluster-nonretentive-0 {
+ compatible = "riscv,idle-state";
+ riscv,sbi-suspend-param = <0x91000000>;
+ local-timer-stop;
+ entry-latency-us = <600>;
+ exit-latency-us = <1100>;
+ min-residency-us = <2700>;
+ wakeup-latency-us = <1500>;
+ };
+
+ CPU_RET_1_0: cpu-retentive-1-0 {
+ compatible = "riscv,idle-state";
+ riscv,sbi-suspend-param = <0x10000010>;
+ entry-latency-us = <20>;
+ exit-latency-us = <40>;
+ min-residency-us = <80>;
+ };
+
+ CPU_NONRET_1_0: cpu-nonretentive-1-0 {
+ compatible = "riscv,idle-state";
+ riscv,sbi-suspend-param = <0x90000010>;
+ entry-latency-us = <250>;
+ exit-latency-us = <500>;
+ min-residency-us = <950>;
+ };
+
+ CLUSTER_RET_1: cluster-retentive-1 {
+ compatible = "riscv,idle-state";
+ riscv,sbi-suspend-param = <0x11000010>;
+ local-timer-stop;
+ entry-latency-us = <50>;
+ exit-latency-us = <100>;
+ min-residency-us = <250>;
+ wakeup-latency-us = <130>;
+ };
+
+ CLUSTER_NONRET_1: cluster-nonretentive-1 {
+ compatible = "riscv,idle-state";
+ riscv,sbi-suspend-param = <0x91000010>;
+ local-timer-stop;
+ entry-latency-us = <600>;
+ exit-latency-us = <1100>;
+ min-residency-us = <2700>;
+ wakeup-latency-us = <1500>;
+ };
+ };
+ };
+
+...