| Message ID | 20220223125536.230224-2-shawn.guo@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | [v6,1/3] PM: cpu: Add CPU_LAST_PM_ENTER and CPU_FIRST_PM_EXIT support | expand |
On Wed, Feb 23, 2022 at 07:30:50PM +0000, Sudeep Holla wrote: > On Wed, Feb 23, 2022 at 08:55:34PM +0800, Shawn Guo wrote: > > It becomes a common situation on some platforms that certain hardware > > setup needs to be done on the last standing cpu, and rpmh-rsc[1] is such > > an existing example. As figuring out the last standing cpu is really > > something generic, it adds CPU_LAST_PM_ENTER (and CPU_FIRST_PM_EXIT) > > event support to cpu_pm helper, so that individual driver can be > > notified when the last standing cpu is about to enter low power state. > > Sorry for not getting back on the previous email thread. > When I meant I didn't want to use CPU_CLUSTER_PM_{ENTER,EXIT}, I wasn't > thinking new ones to be added as alternative. With this OSI cpuidle, we > have introduces the concept of power domains and I was check if we can > associate these requirements to them rather than introducing the first > and last cpu notion. The power domains already identify them in order > to turn on or off. Not sure if there is any notification mechanism in > genpd/power domains. I really don't like this addition. It is disintegrating > all the solutions for OSI and makes it hard to understand. > > One solution I can think of(not sure if others like or if that is feasible) > is to create a parent power domain that encloses all the last level CPU > power domains, which means when the last one is getting powered off, you > will be asked to power off and you can take whatever action you want. Thanks Sudeep for the input! Yes, it works for me (if I understand your suggestion correctly). So the needed changes on top of the current version would be: 1) Declare MPM as a PD (power domain) provider and have it be the parent PD of cpu cluster (the platform has only one cluster including 4 cpus). diff --git a/arch/arm64/boot/dts/qcom/qcm2290.dtsi b/arch/arm64/boot/dts/qcom/qcm2290.dtsi index 5bc5ce0b5d77..0cd0a9722ec5 100644 --- a/arch/arm64/boot/dts/qcom/qcm2290.dtsi +++ b/arch/arm64/boot/dts/qcom/qcm2290.dtsi @@ -240,6 +240,7 @@ CPU_PD3: cpu3 { CLUSTER_PD: cpu-cluster0 { #power-domain-cells = <0>; + power-domains = <&mpm>; domain-idle-states = <&CLUSTER_SLEEP_0>; }; }; @@ -490,6 +491,7 @@ mpm: interrupt-controller@45f01b8 { interrupt-controller; interrupt-parent = <&intc>; #interrupt-cells = <2>; + #power-domain-cells = <0>; qcom,mpm-pin-count = <96>; qcom,mpm-pin-map = <2 275>, /* tsens0_tsens_upper_lower_int */ <5 296>, /* lpass_irq_out_sdc */ 2) Add PD in MPM driver and call qcom_mpm_enter_sleep() from .power_off hook of the PD. diff --git a/drivers/irqchip/qcom-mpm.c b/drivers/irqchip/qcom-mpm.c index d3d8251e57e4..f4409c169a3a 100644 --- a/drivers/irqchip/qcom-mpm.c +++ b/drivers/irqchip/qcom-mpm.c @@ -4,7 +4,6 @@ * Copyright (c) 2010-2020, The Linux Foundation. All rights reserved. */ -#include <linux/cpu_pm.h> #include <linux/delay.h> #include <linux/err.h> #include <linux/init.h> @@ -18,6 +17,7 @@ #include <linux/of.h> #include <linux/of_device.h> #include <linux/platform_device.h> +#include <linux/pm_domain.h> #include <linux/slab.h> #include <linux/soc/qcom/irq.h> #include <linux/spinlock.h> @@ -84,7 +84,7 @@ struct qcom_mpm_priv { unsigned int map_cnt; unsigned int reg_stride; struct irq_domain *domain; - struct notifier_block pm_nb; + struct generic_pm_domain genpd; }; static u32 qcom_mpm_read(struct qcom_mpm_priv *priv, unsigned int reg, @@ -312,23 +312,12 @@ static int qcom_mpm_enter_sleep(struct qcom_mpm_priv *priv) return 0; } -static int qcom_mpm_cpu_pm_callback(struct notifier_block *nb, - unsigned long action, void *data) +static int mpm_pd_power_off(struct generic_pm_domain *genpd) { - struct qcom_mpm_priv *priv = container_of(nb, struct qcom_mpm_priv, - pm_nb); - int ret = NOTIFY_OK; - - switch (action) { - case CPU_LAST_PM_ENTER: - if (qcom_mpm_enter_sleep(priv)) - ret = NOTIFY_BAD; - break; - default: - ret = NOTIFY_DONE; - } + struct qcom_mpm_priv *priv = container_of(genpd, struct qcom_mpm_priv, + genpd); - return ret; + return qcom_mpm_enter_sleep(priv); } static int qcom_mpm_init(struct device_node *np, struct device_node *parent) @@ -336,6 +325,7 @@ static int qcom_mpm_init(struct device_node *np, struct device_node *parent) struct platform_device *pdev = of_find_device_by_node(np); struct device *dev = &pdev->dev; struct irq_domain *parent_domain; + struct generic_pm_domain *genpd; struct qcom_mpm_priv *priv; unsigned int pin_cnt; int i, irq; @@ -387,6 +377,26 @@ static int qcom_mpm_init(struct device_node *np, struct device_node *parent) if (irq < 0) return irq; + genpd = &priv->genpd; + genpd->flags = GENPD_FLAG_IRQ_SAFE; + genpd->power_off = mpm_pd_power_off; + + genpd->name = devm_kasprintf(dev, GFP_KERNEL, "%s", dev_name(dev)); + if (!genpd->name) + return -ENOMEM; + + ret = pm_genpd_init(genpd, NULL, false); + if (ret) { + dev_err(dev, "failed to init genpd: %d\n", ret); + return ret; + } + + ret = of_genpd_add_provider_simple(np, genpd); + if (ret) { + dev_err(dev, "failed to add genpd provider: %d\n", ret); + goto remove_genpd; + } + priv->mbox_client.dev = dev; priv->mbox_chan = mbox_request_channel(&priv->mbox_client, 0); if (IS_ERR(priv->mbox_chan)) { @@ -420,15 +430,14 @@ static int qcom_mpm_init(struct device_node *np, struct device_node *parent) goto remove_domain; } - priv->pm_nb.notifier_call = qcom_mpm_cpu_pm_callback; - cpu_pm_register_notifier(&priv->pm_nb); - return 0; remove_domain: irq_domain_remove(priv->domain); free_mbox: mbox_free_channel(priv->mbox_chan); +remove_genpd: + pm_genpd_remove(genpd); return ret; } Let's me know if this is what you are asking for, thanks! Shawn
diff --git a/include/linux/cpu_pm.h b/include/linux/cpu_pm.h index 552b8f9ea05e..153344307b7c 100644 --- a/include/linux/cpu_pm.h +++ b/include/linux/cpu_pm.h @@ -55,6 +55,21 @@ enum cpu_pm_event { /* A cpu power domain is exiting a low power state */ CPU_CLUSTER_PM_EXIT, + + /* + * A cpu is entering a low power state after all other cpus + * in the system have entered the lower power state. + */ + CPU_LAST_PM_ENTER, + + /* The last cpu failed to enter a low power state */ + CPU_LAST_PM_ENTER_FAILED, + + /* + * A cpu is exiting a low power state before any other cpus + * in the system exits the low power state. + */ + CPU_FIRST_PM_EXIT, }; #ifdef CONFIG_CPU_PM diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c index 246efc74e3f3..7c104446e1e9 100644 --- a/kernel/cpu_pm.c +++ b/kernel/cpu_pm.c @@ -26,6 +26,8 @@ static struct { .lock = __RAW_SPIN_LOCK_UNLOCKED(cpu_pm_notifier.lock), }; +static atomic_t cpus_in_pm; + static int cpu_pm_notify(enum cpu_pm_event event) { int ret; @@ -116,7 +118,20 @@ EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); */ int cpu_pm_enter(void) { - return cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED); + int ret; + + ret = cpu_pm_notify_robust(CPU_PM_ENTER, CPU_PM_ENTER_FAILED); + if (ret) + return ret; + + if (atomic_inc_return(&cpus_in_pm) == num_online_cpus()) { + ret = cpu_pm_notify_robust(CPU_LAST_PM_ENTER, + CPU_LAST_PM_ENTER_FAILED); + if (ret) + return ret; + } + + return 0; } EXPORT_SYMBOL_GPL(cpu_pm_enter); @@ -134,7 +149,21 @@ EXPORT_SYMBOL_GPL(cpu_pm_enter); */ int cpu_pm_exit(void) { - return cpu_pm_notify(CPU_PM_EXIT); + int ret; + + ret = cpu_pm_notify(CPU_PM_EXIT); + if (ret) + return ret; + + if (atomic_read(&cpus_in_pm) == num_online_cpus()) { + ret = cpu_pm_notify(CPU_FIRST_PM_EXIT); + if (ret) + return ret; + } + + atomic_dec(&cpus_in_pm); + + return 0; } EXPORT_SYMBOL_GPL(cpu_pm_exit);
It becomes a common situation on some platforms that certain hardware setup needs to be done on the last standing cpu, and rpmh-rsc[1] is such an existing example. As figuring out the last standing cpu is really something generic, it adds CPU_LAST_PM_ENTER (and CPU_FIRST_PM_EXIT) event support to cpu_pm helper, so that individual driver can be notified when the last standing cpu is about to enter low power state. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/soc/qcom/rpmh-rsc.c?id=v5.16#n773 Signed-off-by: Shawn Guo <shawn.guo@linaro.org> --- include/linux/cpu_pm.h | 15 +++++++++++++++ kernel/cpu_pm.c | 33 +++++++++++++++++++++++++++++++-- 2 files changed, 46 insertions(+), 2 deletions(-)