diff options
Diffstat (limited to 'Documentation/devicetree/bindings/arm/msm')
5 files changed, 215 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt b/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt new file mode 100644 index 000000000..06df04cc8 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt @@ -0,0 +1,84 @@ +QCOM Idle States for cpuidle driver + +ARM provides idle-state node to define the cpuidle states, as defined in [1]. +cpuidle-qcom is the cpuidle driver for Qualcomm SoCs and uses these idle +states. Idle states have different enter/exit latency and residency values. +The idle states supported by the QCOM SoC are defined as - + + * Standby + * Retention + * Standalone Power Collapse (Standalone PC or SPC) + * Power Collapse (PC) + +Standby: Standby does a little more in addition to architectural clock gating. +When the WFI instruction is executed the ARM core would gate its internal +clocks. In addition to gating the clocks, QCOM cpus use this instruction as a +trigger to execute the SPM state machine. The SPM state machine waits for the +interrupt to trigger the core back in to active. This triggers the cache +hierarchy to enter standby states, when all cpus are idle. An interrupt brings +the SPM state machine out of its wait, the next step is to ensure that the +cache hierarchy is also out of standby, and then the cpu is allowed to resume +execution. This state is defined as a generic ARM WFI state by the ARM cpuidle +driver and is not defined in the DT. The SPM state machine should be +configured to execute this state by default and after executing every other +state below. + +Retention: Retention is a low power state where the core is clock gated and +the memory and the registers associated with the core are retained. The +voltage may be reduced to the minimum value needed to keep the processor +registers active. The SPM should be configured to execute the retention +sequence and would wait for interrupt, before restoring the cpu to execution +state. Retention may have a slightly higher latency than Standby. + +Standalone PC: A cpu can power down and warmboot if there is a sufficient time +between the time it enters idle and the next known wake up. SPC mode is used +to indicate a core entering a power down state without consulting any other +cpu or the system resources. This helps save power only on that core. The SPM +sequence for this idle state is programmed to power down the supply to the +core, wait for the interrupt, restore power to the core, and ensure the +system state including cache hierarchy is ready before allowing core to +resume. Applying power and resetting the core causes the core to warmboot +back into Elevation Level (EL) which trampolines the control back to the +kernel. Entering a power down state for the cpu, needs to be done by trapping +into a EL. Failing to do so, would result in a crash enforced by the warm boot +code in the EL for the SoC. On SoCs with write-back L1 cache, the cache has to +be flushed in s/w, before powering down the core. + +Power Collapse: This state is similar to the SPC mode, but distinguishes +itself in that the cpu acknowledges and permits the SoC to enter deeper sleep +modes. In a hierarchical power domain SoC, this means L2 and other caches can +be flushed, system bus, clocks - lowered, and SoC main XO clock gated and +voltages reduced, provided all cpus enter this state. Since the span of low +power modes possible at this state is vast, the exit latency and the residency +of this low power mode would be considered high even though at a cpu level, +this essentially is cpu power down. The SPM in this state also may handshake +with the Resource power manager (RPM) processor in the SoC to indicate a +complete application processor subsystem shut down. + +The idle-state for QCOM SoCs are distinguished by the compatible property of +the idle-states device node. + +The devicetree representation of the idle state should be - + +Required properties: + +- compatible: Must be one of - + "qcom,idle-state-ret", + "qcom,idle-state-spc", + "qcom,idle-state-pc", + and "arm,idle-state". + +Other required and optional properties are specified in [1]. + +Example: + + idle-states { + CPU_SPC: spc { + compatible = "qcom,idle-state-spc", "arm,idle-state"; + entry-latency-us = <150>; + exit-latency-us = <200>; + min-residency-us = <2000>; + }; + }; + +[1]. Documentation/devicetree/bindings/arm/idle-states.txt diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt b/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt new file mode 100644 index 000000000..1333db9ac --- /dev/null +++ b/Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt @@ -0,0 +1,30 @@ +Krait Processor Sub-system (KPSS) Application Clock Controller (ACC) + +The KPSS ACC provides clock, power domain, and reset control to a Krait CPU. +There is one ACC register region per CPU within the KPSS remapped region as +well as an alias register region that remaps accesses to the ACC associated +with the CPU accessing the region. + +PROPERTIES + +- compatible: + Usage: required + Value type: <string> + Definition: should be one of: + "qcom,kpss-acc-v1" + "qcom,kpss-acc-v2" + +- reg: + Usage: required + Value type: <prop-encoded-array> + Definition: the first element specifies the base address and size of + the register region. An optional second element specifies + the base address and size of the alias register region. + +Example: + + clock-controller@2088000 { + compatible = "qcom,kpss-acc-v2"; + reg = <0x02088000 0x1000>, + <0x02008000 0x1000>; + }; diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,llcc.txt b/Documentation/devicetree/bindings/arm/msm/qcom,llcc.txt new file mode 100644 index 000000000..5e8574926 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/msm/qcom,llcc.txt @@ -0,0 +1,26 @@ +== Introduction== + +LLCC (Last Level Cache Controller) provides last level of cache memory in SOC, +that can be shared by multiple clients. Clients here are different cores in the +SOC, the idea is to minimize the local caches at the clients and migrate to +common pool of memory. Cache memory is divided into partitions called slices +which are assigned to clients. Clients can query the slice details, activate +and deactivate them. + +Properties: +- compatible: + Usage: required + Value type: <string> + Definition: must be "qcom,sdm845-llcc" + +- reg: + Usage: required + Value Type: <prop-encoded-array> + Definition: Start address and the the size of the register region. + +Example: + + cache-controller@1100000 { + compatible = "qcom,sdm845-llcc"; + reg = <0x1100000 0x250000>; + }; diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt new file mode 100644 index 000000000..ae4afc6dc --- /dev/null +++ b/Documentation/devicetree/bindings/arm/msm/qcom,saw2.txt @@ -0,0 +1,57 @@ +SPM AVS Wrapper 2 (SAW2) + +The SAW2 is a wrapper around the Subsystem Power Manager (SPM) and the +Adaptive Voltage Scaling (AVS) hardware. The SPM is a programmable +power-controller that transitions a piece of hardware (like a processor or +subsystem) into and out of low power modes via a direct connection to +the PMIC. It can also be wired up to interact with other processors in the +system, notifying them when a low power state is entered or exited. + +Multiple revisions of the SAW hardware are supported using these Device Nodes. +SAW2 revisions differ in the register offset and configuration data. Also, the +same revision of the SAW in different SoCs may have different configuration +data due the the differences in hardware capabilities. Hence the SoC name, the +version of the SAW hardware in that SoC and the distinction between cpu (big +or Little) or cache, may be needed to uniquely identify the SAW register +configuration and initialization data. The compatible string is used to +indicate this parameter. + +PROPERTIES + +- compatible: + Usage: required + Value type: <string> + Definition: Must have + "qcom,saw2" + A more specific value could be one of: + "qcom,apq8064-saw2-v1.1-cpu" + "qcom,msm8974-saw2-v2.1-cpu" + "qcom,apq8084-saw2-v2.1-cpu" + +- reg: + Usage: required + Value type: <prop-encoded-array> + Definition: the first element specifies the base address and size of + the register region. An optional second element specifies + the base address and size of the alias register region. + +- regulator: + Usage: optional + Value type: boolean + Definition: Indicates that this SPM device acts as a regulator device + device for the core (CPU or Cache) the SPM is attached + to. + +Example 1: + + power-controller@2099000 { + compatible = "qcom,saw2"; + reg = <0x02099000 0x1000>, <0x02009000 0x1000>; + regulator; + }; + +Example 2: + saw0: power-controller@f9089000 { + compatible = "qcom,apq8084-saw2-v2.1-cpu", "qcom,saw2"; + reg = <0xf9089000 0x1000>, <0xf9009000 0x1000>; + }; diff --git a/Documentation/devicetree/bindings/arm/msm/ssbi.txt b/Documentation/devicetree/bindings/arm/msm/ssbi.txt new file mode 100644 index 000000000..54fd5ced3 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/msm/ssbi.txt @@ -0,0 +1,18 @@ +* Qualcomm SSBI + +Some Qualcomm MSM devices contain a point-to-point serial bus used to +communicate with a limited range of devices (mostly power management +chips). + +These require the following properties: + +- compatible: "qcom,ssbi" + +- qcom,controller-type + indicates the SSBI bus variant the controller should use to talk + with the slave device. This should be one of "ssbi", "ssbi2", or + "pmic-arbiter". The type chosen is determined by the attached + slave. + +The slave device should be the single child node of the ssbi device +with a compatible field. |