[v10,07/10] qcom: cpuidle: Add cpuidle driver for QCOM cpus

Message ID	1416593037-27527-8-git-send-email-lina.iyer@linaro.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> From: Lina Iyer <lina.iyer@linaro.org> To: daniel.lezcano@linaro.org, khilman@linaro.org, sboyd@codeaurora.org, galak@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH v10 07/10] qcom: cpuidle: Add cpuidle driver for QCOM cpus Date: Fri, 21 Nov 2014 11:03:54 -0700 Message-Id: <1416593037-27527-8-git-send-email-lina.iyer@linaro.org> In-Reply-To: <1416593037-27527-1-git-send-email-lina.iyer@linaro.org> References: <1416593037-27527-1-git-send-email-lina.iyer@linaro.org> Cc: msivasub@codeaurora.org, devicetree@vger.kernel.org, lorenzo.pieralisi@arm.com, Lina Iyer <lina.iyer@linaro.org> Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

On Fri, Nov 21, 2014 at 06:03:54PM +0000, Lina Iyer wrote: > Add cpuidle driver interface to allow cpus to go into C-States. Use the "idle states" please. > cpuidle DT interface, common across ARM architectures, to provide the > idle state information to the cpuidle framework. > > Supported modes at this time are Standby and Standalone Power Collapse. > > Signed-off-by: Lina Iyer <lina.iyer@linaro.org> > --- > .../bindings/arm/msm/qcom,idle-state.txt | 81 ++++++++++++++++++++++ > drivers/cpuidle/Kconfig.arm | 7 ++ > drivers/cpuidle/Makefile | 1 + > drivers/cpuidle/cpuidle-qcom.c | 72 +++++++++++++++++++ > 4 files changed, 161 insertions(+) > create mode 100644 Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt > create mode 100644 drivers/cpuidle/cpuidle-qcom.c > > 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 0000000..ae1b07f > --- /dev/null > +++ b/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt > @@ -0,0 +1,81 @@ > +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. > + > +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 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-stby", > + "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/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm > index 8c16ab2..e98993c 100644 > --- a/drivers/cpuidle/Kconfig.arm > +++ b/drivers/cpuidle/Kconfig.arm > @@ -63,3 +63,10 @@ config ARM_MVEBU_V7_CPUIDLE > depends on ARCH_MVEBU > help > Select this to enable cpuidle on Armada 370, 38x and XP processors. > + > +config ARM_QCOM_CPUIDLE > + bool "CPU Idle drivers for Qualcomm processors" > + depends on ARCH_QCOM > + select DT_IDLE_STATES > + help > + Select this to enable cpuidle for QCOM processors > diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile > index 4d177b9..6c222d5 100644 > --- a/drivers/cpuidle/Makefile > +++ b/drivers/cpuidle/Makefile > @@ -17,6 +17,7 @@ obj-$(CONFIG_ARM_ZYNQ_CPUIDLE) += cpuidle-zynq.o > obj-$(CONFIG_ARM_U8500_CPUIDLE) += cpuidle-ux500.o > obj-$(CONFIG_ARM_AT91_CPUIDLE) += cpuidle-at91.o > obj-$(CONFIG_ARM_EXYNOS_CPUIDLE) += cpuidle-exynos.o > +obj-$(CONFIG_ARM_QCOM_CPUIDLE) += cpuidle-qcom.o > > ############################################################################### > # MIPS drivers > diff --git a/drivers/cpuidle/cpuidle-qcom.c b/drivers/cpuidle/cpuidle-qcom.c > new file mode 100644 > index 0000000..1c1dcbc > --- /dev/null > +++ b/drivers/cpuidle/cpuidle-qcom.c > @@ -0,0 +1,72 @@ > +/* > + * Copyright (c) 2014, Linaro Limited. > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 and > + * only version 2 as published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + */ > + > +#include <linux/cpuidle.h> > +#include <linux/module.h> > +#include <linux/platform_device.h> > + > +#include <soc/qcom/pm.h> > +#include "dt_idle_states.h" > + > +static struct qcom_cpu_pm_ops *lpm_ops; > + > +static int qcom_cpu_stby(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, int index) > +{ > + lpm_ops->standby(NULL); > + > + return index; > +} > + > +static int qcom_cpu_spc(struct cpuidle_device *dev, > + struct cpuidle_driver *drv, int index) > +{ > + lpm_ops->spc(NULL); > + > + return index; > +} Check power down functions return codes please as Daniel already pointed out, this might skew stats and prevent debugging. > +static struct cpuidle_driver qcom_cpuidle_driver = { > + .name = "qcom_cpuidle", > +}; > + > +static const struct of_device_id qcom_idle_state_match[] = { > + { .compatible = "qcom,idle-state-stby", .data = qcom_cpu_stby}, > + { .compatible = "qcom,idle-state-spc", .data = qcom_cpu_spc }, > + { }, > +}; > + > +static int qcom_cpuidle_probe(struct platform_device *pdev) > +{ > + struct cpuidle_driver *drv = &qcom_cpuidle_driver; > + int ret; > + > + lpm_ops = pdev->dev.platform_data; > + > + /* Probe for other states, including standby */ > + ret = dt_init_idle_driver(drv, qcom_idle_state_match, 0); > + if (ret < 0) > + return ret; > + > + return cpuidle_register(drv, NULL); > +} > + > +static struct platform_driver qcom_cpuidle_plat_driver = { > + .probe = qcom_cpuidle_probe, > + .driver = { > + .name = "qcom_cpuidle", > + }, > +}; > + > +module_platform_driver(qcom_cpuidle_plat_driver); Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

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 0000000..ae1b07f --- /dev/null +++ b/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt @@ -0,0 +1,81 @@ +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. + +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 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-stby", + "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/drivers/cpuidle/Kconfig.arm b/drivers/cpuidle/Kconfig.arm index 8c16ab2..e98993c 100644 --- a/drivers/cpuidle/Kconfig.arm +++ b/drivers/cpuidle/Kconfig.arm @@ -63,3 +63,10 @@ config ARM_MVEBU_V7_CPUIDLE depends on ARCH_MVEBU help Select this to enable cpuidle on Armada 370, 38x and XP processors. + +config ARM_QCOM_CPUIDLE + bool "CPU Idle drivers for Qualcomm processors" + depends on ARCH_QCOM + select DT_IDLE_STATES + help + Select this to enable cpuidle for QCOM processors diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile index 4d177b9..6c222d5 100644 --- a/drivers/cpuidle/Makefile +++ b/drivers/cpuidle/Makefile @@ -17,6 +17,7 @@ obj-$(CONFIG_ARM_ZYNQ_CPUIDLE) += cpuidle-zynq.o obj-$(CONFIG_ARM_U8500_CPUIDLE) += cpuidle-ux500.o obj-$(CONFIG_ARM_AT91_CPUIDLE) += cpuidle-at91.o obj-$(CONFIG_ARM_EXYNOS_CPUIDLE) += cpuidle-exynos.o +obj-$(CONFIG_ARM_QCOM_CPUIDLE) += cpuidle-qcom.o ############################################################################### # MIPS drivers diff --git a/drivers/cpuidle/cpuidle-qcom.c b/drivers/cpuidle/cpuidle-qcom.c new file mode 100644 index 0000000..1c1dcbc --- /dev/null +++ b/drivers/cpuidle/cpuidle-qcom.c @@ -0,0 +1,72 @@ +/* + * Copyright (c) 2014, Linaro Limited. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/cpuidle.h> +#include <linux/module.h> +#include <linux/platform_device.h> + +#include <soc/qcom/pm.h> +#include "dt_idle_states.h" + +static struct qcom_cpu_pm_ops *lpm_ops; + +static int qcom_cpu_stby(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) +{ + lpm_ops->standby(NULL); + + return index; +} + +static int qcom_cpu_spc(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) +{ + lpm_ops->spc(NULL); + + return index; +} + +static struct cpuidle_driver qcom_cpuidle_driver = { + .name = "qcom_cpuidle", +}; + +static const struct of_device_id qcom_idle_state_match[] = { + { .compatible = "qcom,idle-state-stby", .data = qcom_cpu_stby}, + { .compatible = "qcom,idle-state-spc", .data = qcom_cpu_spc }, + { }, +}; + +static int qcom_cpuidle_probe(struct platform_device *pdev) +{ + struct cpuidle_driver *drv = &qcom_cpuidle_driver; + int ret; + + lpm_ops = pdev->dev.platform_data; + + /* Probe for other states, including standby */ + ret = dt_init_idle_driver(drv, qcom_idle_state_match, 0); + if (ret < 0) + return ret; + + return cpuidle_register(drv, NULL); +} + +static struct platform_driver qcom_cpuidle_plat_driver = { + .probe = qcom_cpuidle_probe, + .driver = { + .name = "qcom_cpuidle", + }, +}; + +module_platform_driver(qcom_cpuidle_plat_driver);

[v10,07/10] qcom: cpuidle: Add cpuidle driver for QCOM cpus

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