On 11/17, Lina Iyer wrote:
> diff --git a/Documentation/arm/cpu-domains.txt
> b/Documentation/arm/cpu-domains.txt
> new file mode 100644
> index 0000000..ef5f215
> --- /dev/null
> +++ b/Documentation/arm/cpu-domains.txt
> @@ -0,0 +1,52 @@
> +CPU Clusters and PM domain
> +
> +Newer CPUs are grouped in a SoC as clusters. A cluster in addition to the
> +CPUs may have caches, GIC, VFP and architecture specific power controller to
> +power the cluster. A cluster may also be nested in another cluster, the
> +hierarchy of which is depicted in the device tree. CPUIdle frameworks enables
s/frameworks/framework/?
s/depicted/described/? Hopefully we aren't putting pictures or
art in DT for this sort of stuff.
> diff --git a/drivers/base/power/cpu-pd.c b/drivers/base/power/cpu-pd.c
> new file mode 100644
> index 0000000..9758b8d
> --- /dev/null
> +++ b/drivers/base/power/cpu-pd.c
> @@ -0,0 +1,231 @@
> +/*
> + * CPU Generic PM Domain.
> + *
> + * Copyright (C) 2015 Linaro Ltd.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#define DEBUG
> +
> +#include <linux/kernel.h>
> +#include <linux/export.h>
> +#include <linux/cpu.h>
> +#include <linux/cpu_pm.h>
> +#include <linux/cpu-pd.h>
> +#include <linux/device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/platform_device.h>
Is this used?
> +#include <linux/rculist.h>
> +#include <linux/slab.h>
> +
> +#define CPU_PD_NAME_MAX 36
> +
[...]
> +static int of_pm_domain_attach_cpus(struct device_node *dn)
> +{
> + int cpuid, ret;
> +
> + /* Find any CPU nodes with a phandle to this power domain */
> + for_each_possible_cpu(cpuid) {
> + struct device *cpu_dev;
> + struct device_node *cpu_pd;
> +
> + cpu_dev = get_cpu_device(cpuid);
> + if (!cpu_dev) {
> + pr_warn("%s: Unable to get device for CPU%d\n",
> + __func__, cpuid);
> + return -ENODEV;
> + }
> +
> + /* Only attach CPUs that are part of this domain */
> + cpu_pd = of_parse_phandle(cpu_dev->of_node, "power-domains", 0);
> + if (cpu_pd != dn)
> + continue;
> +
> + if (cpu_online(cpuid)) {
I guess we don't care if hotplug is running in parallel to this
code?
> + pm_runtime_set_active(cpu_dev);
> + /*
> + * Execute the below on that 'cpu' to ensure that the
> + * reference counting is correct. It's possible that
> + * while this code is executing, the 'cpu' may be
> + * powered down, but we may incorrectly increment the
> + * usage. By executing the get_cpu on the 'cpu',
> + * we can ensure that the 'cpu' and its usage count are
> + * matched.
> + */
> + smp_call_function_single(cpuid, run_cpu, NULL, true);
> + } else {
> + pm_runtime_set_suspended(cpu_dev);
> + }
> +
> + ret = genpd_dev_pm_attach(cpu_dev);
> + if (ret) {
> + dev_warn(cpu_dev,
> + "%s: Unable to attach to power-domain: %d\n",
> + __func__, ret);
> + } else {
> + pm_runtime_enable(cpu_dev);
> + dev_dbg(cpu_dev, "Attached CPU%d to domain\n", cpuid);
> + }
> + }
> +
> + return 0;
> +}
> +
> +int of_register_cpu_pm_domain(struct device_node *dn,
static?
> + struct cpu_pm_domain *pd)
> +{
> + int ret;
> +
> + if (!pd || !pd->genpd)
> + return -EINVAL;
> +
> + /*
> + * The platform should not set up the genpd callbacks.
> + * They should setup the pd->plat_ops instead.
> + */
> + WARN_ON(pd->genpd->power_off);
> + WARN_ON(pd->genpd->power_on);
> +
> + pd->genpd->power_off = cpu_pd_power_off;
> + pd->genpd->power_on = cpu_pd_power_on;
> + pd->genpd->flags |= GENPD_FLAG_IRQ_SAFE;
> +
> + INIT_LIST_HEAD_RCU(&pd->link);
> + spin_lock(&cpu_pd_list_lock);
> + list_add_rcu(&pd->link, &of_cpu_pd_list);
> + spin_unlock(&cpu_pd_list_lock);
> + pd->dn = dn;
> +
> + /* Register the CPU genpd */
> + pr_debug("adding %s as CPU PM domain.\n", pd->genpd->name);
> + ret = of_pm_genpd_init(dn, pd->genpd, &simple_qos_governor, false);
> + if (ret) {
> + pr_err("Unable to initialize domain %s\n", dn->full_name);
> + return ret;
> + }
> +
> + ret = of_genpd_add_provider_simple(dn, pd->genpd);
> + if (ret)
> + pr_warn("Unable to add genpd %s as provider\n",
> + pd->genpd->name);
> +
> + /* Attach the CPUs to the CPU PM domain */
> + ret = of_pm_domain_attach_cpus(dn);
> + if (ret)
> + of_genpd_del_provider(dn);
> +
> + return ret;
> +}
> +
> +/**
> + * of_init_cpu_pm_domain() - Initialize a CPU PM domain using the CPU pd
> + * provided
> + * @dn: PM domain provider device node
> + * @ops: CPU PM domain platform specific ops for callback
> + *
> + * This is a single step initialize the CPU PM domain with defaults,
> + * also register the genpd and attach CPUs to the genpd.
Returns?
> + */
> +struct generic_pm_domain *of_init_cpu_pm_domain(struct device_node *dn,
> + const struct cpu_pd_ops *ops)
> +{
> + struct cpu_pm_domain *pd;
> + int ret;
> +
> + if (!of_device_is_available(dn))
> + return ERR_PTR(-ENODEV);
> +
> + pd = kzalloc(sizeof(*pd), GFP_KERNEL);
> + if (!pd)
> + return ERR_PTR(-ENOMEM);
> +
> + pd->genpd = kzalloc(sizeof(*(pd->genpd)), GFP_KERNEL);
> + if (!pd->genpd) {
> + kfree(pd);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + pd->genpd->name = kstrndup(dn->full_name, CPU_PD_NAME_MAX, GFP_KERNEL);
> + if (!pd->genpd->name) {
> + kfree(pd->genpd);
> + kfree(pd);
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + if (ops) {
> + pd->plat_ops.power_off = ops->power_off;
> + pd->plat_ops.power_on = ops->power_on;
> + }
> +
> + ret = of_register_cpu_pm_domain(dn, pd);
> + if (ret) {
> + kfree(pd->genpd->name);
> + kfree(pd->genpd);
> + kfree(pd);
> + return ERR_PTR(ret);
Maybe we can have a goto error path so that we don't duplicate
these kfree calls a bunch of times.
> + }
> +
> + return pd->genpd;
> +}
> +EXPORT_SYMBOL(of_init_cpu_pm_domain);
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