From patchwork Fri Dec 24 14:48:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Heidelberg X-Patchwork-Id: 527791 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9419FC433EF for ; Fri, 24 Dec 2021 14:48:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241647AbhLXOsk (ORCPT ); Fri, 24 Dec 2021 09:48:40 -0500 Received: from ixit.cz ([94.230.151.217]:49562 "EHLO ixit.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231836AbhLXOsk (ORCPT ); Fri, 24 Dec 2021 09:48:40 -0500 Received: from localhost.localdomain (ip-89-176-96-70.net.upcbroadband.cz [89.176.96.70]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ixit.cz (Postfix) with ESMTPSA id 68F952243C; Fri, 24 Dec 2021 15:48:37 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ixit.cz; s=dkim; t=1640357317; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=mR8uorQ2/cBIUnBEfvoxTcBWsRXZKWWQDqPfp3FOr4w=; b=Jf8D8BQMMhmvd2f4Xil1oR2+DH6IVSKw/WXb6zuzH4xrxPGoI73taWeAsLFHxW+leZwQdB InZNMcdISkSvUS6DhJ3MjhwIOzwRfgi5psZDgVbdL6YAFgARDHZ0+SVUVTJaDoOVLxcULz AaCHB8nAJpFy32G+DWhx4FSG7bTW8AE= From: David Heidelberg To: Rob Herring , Lorenzo Pieralisi Cc: ~okias/devicetree@lists.sr.ht, David Heidelberg , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3] dt-bindings: arm: merge qcom,idle-state with idle-state Date: Fri, 24 Dec 2021 15:48:34 +0100 Message-Id: <20211224144835.39193-1-david@ixit.cz> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Merge Qualcomm specific idle-state binding with generic one. Signed-off-by: David Heidelberg --- v3: - integrate into idle-state.yml - orig. patch name was: "[v2] dt-bindings: arm/msm/qcom,idle-state convert to YAML" Signed-off-by: David Heidelberg --- .../devicetree/bindings/arm/idle-states.yaml | 107 ++++++++++++++++++ .../bindings/arm/msm/qcom,idle-state.txt | 84 -------------- 2 files changed, 107 insertions(+), 84 deletions(-) delete mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt diff --git a/Documentation/devicetree/bindings/arm/idle-states.yaml b/Documentation/devicetree/bindings/arm/idle-states.yaml index 52bce5dbb11f..fde1557f2332 100644 --- a/Documentation/devicetree/bindings/arm/idle-states.yaml +++ b/Documentation/devicetree/bindings/arm/idle-states.yaml @@ -241,6 +241,64 @@ description: |+ [6] ARM Linux Kernel documentation - Booting AArch64 Linux Documentation/arm64/booting.rst + =========================================== + 5 - Qualcomm specific STATES + =========================================== + + 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. + properties: $nodename: const: idle-states @@ -323,6 +381,44 @@ patternProperties: - exit-latency-us - min-residency-us + "^(ret|spc|pc)$": + type: object + description: + Each state node represents a domain idle state description. + + properties: + compatible: + items: + - enum: + - qcom,idle-state-ret + - qcom,idle-state-spc + - qcom,idle-state-pc + - const: arm,idle-state + + entry-latency-us: + description: + The worst case latency in microseconds required to enter the idle + state. Note that, the exit-latency-us duration may be guaranteed only + after the entry-latency-us has passed. + + exit-latency-us: + description: + The worst case latency in microseconds required to exit the idle + state. + + min-residency-us: + description: + The minimum residency duration in microseconds after which the idle + state will yield power benefits, after overcoming the overhead while + entering the idle state. + + required: + - compatible + - entry-latency-us + - exit-latency-us + - min-residency-us + + additionalProperties: false examples: @@ -658,4 +754,15 @@ examples: }; }; + - | + // Example 3 - QCOM SPC + 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>; + }; + }; + ... diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt b/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt deleted file mode 100644 index 6ce0b212ec6d..000000000000 --- a/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt +++ /dev/null @@ -1,84 +0,0 @@ -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.yaml