cpuidle: Add RISC-V SBI CPU idle driver (6abf32f1) · Commits · EulixOS / Software / Kernel

MAINTAINERS

+7 −0

Original line number	Diff line number	Diff line
		@@ -5058,6 +5058,13 @@ S: Supported
		F: drivers/cpuidle/dt_idle_genpd.c
		F: drivers/cpuidle/dt_idle_genpd.h

		CPUIDLE DRIVER - RISC-V SBI
		M: Anup Patel <anup@brainfault.org>
		L: linux-pm@vger.kernel.org
		L: linux-riscv@lists.infradead.org
		S: Maintained
		F: drivers/cpuidle/cpuidle-riscv-sbi.c

		CRAMFS FILESYSTEM
		M: Nicolas Pitre <nico@fluxnic.net>
		S: Maintained

drivers/cpuidle/Kconfig

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Original line number	Diff line number	Diff line
		@@ -66,6 +66,11 @@ depends on PPC
		source "drivers/cpuidle/Kconfig.powerpc"
		endmenu

		menu "RISC-V CPU Idle Drivers"
		depends on RISCV
		source "drivers/cpuidle/Kconfig.riscv"
		endmenu

		config HALTPOLL_CPUIDLE
		tristate "Halt poll cpuidle driver"
		depends on X86 && KVM_GUEST

drivers/cpuidle/Kconfig.riscv

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+15 −0

Original line number	Diff line number	Diff line
		# SPDX-License-Identifier: GPL-2.0-only
		#
		# RISC-V CPU Idle drivers
		#

		config RISCV_SBI_CPUIDLE
		bool "RISC-V SBI CPU idle Driver"
		depends on RISCV_SBI
		select DT_IDLE_STATES
		select CPU_IDLE_MULTIPLE_DRIVERS
		select DT_IDLE_GENPD if PM_GENERIC_DOMAINS_OF
		help
		Select this option to enable RISC-V SBI firmware based CPU idle
		driver for RISC-V systems. This drivers also supports hierarchical
		DT based layout of the idle state.

drivers/cpuidle/Makefile

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Original line number	Diff line number	Diff line
		@@ -35,3 +35,7 @@ obj-$(CONFIG_MIPS_CPS_CPUIDLE) += cpuidle-cps.o
		# POWERPC drivers
		obj-$(CONFIG_PSERIES_CPUIDLE) += cpuidle-pseries.o
		obj-$(CONFIG_POWERNV_CPUIDLE) += cpuidle-powernv.o

		###############################################################################
		# RISC-V drivers
		obj-$(CONFIG_RISCV_SBI_CPUIDLE) += cpuidle-riscv-sbi.o

drivers/cpuidle/cpuidle-riscv-sbi.c

0 → 100644

+627 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0-only
		/*
		* RISC-V SBI CPU idle driver.
		*
		* Copyright (c) 2021 Western Digital Corporation or its affiliates.
		* Copyright (c) 2022 Ventana Micro Systems Inc.
		*/

		#define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt

		#include <linux/cpuidle.h>
		#include <linux/cpumask.h>
		#include <linux/cpu_pm.h>
		#include <linux/cpu_cooling.h>
		#include <linux/kernel.h>
		#include <linux/module.h>
		#include <linux/of.h>
		#include <linux/of_device.h>
		#include <linux/slab.h>
		#include <linux/platform_device.h>
		#include <linux/pm_domain.h>
		#include <linux/pm_runtime.h>
		#include <asm/cpuidle.h>
		#include <asm/sbi.h>
		#include <asm/suspend.h>

		#include "dt_idle_states.h"
		#include "dt_idle_genpd.h"

		struct sbi_cpuidle_data {
		u32 *states;
		struct device *dev;
		};

		struct sbi_domain_state {
		bool available;
		u32 state;
		};

		static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
		static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
		static bool sbi_cpuidle_use_osi;
		static bool sbi_cpuidle_use_cpuhp;
		static bool sbi_cpuidle_pd_allow_domain_state;

		static inline void sbi_set_domain_state(u32 state)
		{
		struct sbi_domain_state *data = this_cpu_ptr(&domain_state);

		data->available = true;
		data->state = state;
		}

		static inline u32 sbi_get_domain_state(void)
		{
		struct sbi_domain_state *data = this_cpu_ptr(&domain_state);

		return data->state;
		}

		static inline void sbi_clear_domain_state(void)
		{
		struct sbi_domain_state *data = this_cpu_ptr(&domain_state);

		data->available = false;
		}

		static inline bool sbi_is_domain_state_available(void)
		{
		struct sbi_domain_state *data = this_cpu_ptr(&domain_state);

		return data->available;
		}

		static int sbi_suspend_finisher(unsigned long suspend_type,
		unsigned long resume_addr,
		unsigned long opaque)
		{
		struct sbiret ret;

		ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
		suspend_type, resume_addr, opaque, 0, 0, 0);

		return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
		}

		static int sbi_suspend(u32 state)
		{
		if (state & SBI_HSM_SUSP_NON_RET_BIT)
		return cpu_suspend(state, sbi_suspend_finisher);
		else
		return sbi_suspend_finisher(state, 0, 0);
		}

		static int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
		struct cpuidle_driver *drv, int idx)
		{
		u32 *states = __this_cpu_read(sbi_cpuidle_data.states);

		return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, states[idx]);
		}

		static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
		struct cpuidle_driver *drv, int idx,
		bool s2idle)
		{
		struct sbi_cpuidle_data *data = this_cpu_ptr(&sbi_cpuidle_data);
		u32 *states = data->states;
		struct device *pd_dev = data->dev;
		u32 state;
		int ret;

		ret = cpu_pm_enter();
		if (ret)
		return -1;

		/* Do runtime PM to manage a hierarchical CPU toplogy. */
		rcu_irq_enter_irqson();
		if (s2idle)
		dev_pm_genpd_suspend(pd_dev);
		else
		pm_runtime_put_sync_suspend(pd_dev);
		rcu_irq_exit_irqson();

		if (sbi_is_domain_state_available())
		state = sbi_get_domain_state();
		else
		state = states[idx];

		ret = sbi_suspend(state) ? -1 : idx;

		rcu_irq_enter_irqson();
		if (s2idle)
		dev_pm_genpd_resume(pd_dev);
		else
		pm_runtime_get_sync(pd_dev);
		rcu_irq_exit_irqson();

		cpu_pm_exit();

		/* Clear the domain state to start fresh when back from idle. */
		sbi_clear_domain_state();
		return ret;
		}

		static int sbi_enter_domain_idle_state(struct cpuidle_device *dev,
		struct cpuidle_driver *drv, int idx)
		{
		return __sbi_enter_domain_idle_state(dev, drv, idx, false);
		}

		static int sbi_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
		struct cpuidle_driver *drv,
		int idx)
		{
		return __sbi_enter_domain_idle_state(dev, drv, idx, true);
		}

		static int sbi_cpuidle_cpuhp_up(unsigned int cpu)
		{
		struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);

		if (pd_dev)
		pm_runtime_get_sync(pd_dev);

		return 0;
		}

		static int sbi_cpuidle_cpuhp_down(unsigned int cpu)
		{
		struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);

		if (pd_dev) {
		pm_runtime_put_sync(pd_dev);
		/* Clear domain state to start fresh at next online. */
		sbi_clear_domain_state();
		}

		return 0;
		}

		static void sbi_idle_init_cpuhp(void)
		{
		int err;

		if (!sbi_cpuidle_use_cpuhp)
		return;

		err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
		"cpuidle/sbi:online",
		sbi_cpuidle_cpuhp_up,
		sbi_cpuidle_cpuhp_down);
		if (err)
		pr_warn("Failed %d while setup cpuhp state\n", err);
		}

		static const struct of_device_id sbi_cpuidle_state_match[] = {
		{ .compatible = "riscv,idle-state",
		.data = sbi_cpuidle_enter_state },
		{ },
		};

		static bool sbi_suspend_state_is_valid(u32 state)
		{
		if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
		state < SBI_HSM_SUSPEND_RET_PLATFORM)
		return false;
		if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
		state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
		return false;
		return true;
		}

		static int sbi_dt_parse_state_node(struct device_node np, u32 state)
		{
		int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);

		if (err) {
		pr_warn("%pOF missing riscv,sbi-suspend-param property\n", np);
		return err;
		}

		if (!sbi_suspend_state_is_valid(*state)) {
		pr_warn("Invalid SBI suspend state %#x\n", *state);
		return -EINVAL;
		}

		return 0;
		}

		static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
		struct sbi_cpuidle_data *data,
		unsigned int state_count, int cpu)
		{
		/* Currently limit the hierarchical topology to be used in OSI mode. */
		if (!sbi_cpuidle_use_osi)
		return 0;

		data->dev = dt_idle_attach_cpu(cpu, "sbi");
		if (IS_ERR_OR_NULL(data->dev))
		return PTR_ERR_OR_ZERO(data->dev);

		/*
		* Using the deepest state for the CPU to trigger a potential selection
		* of a shared state for the domain, assumes the domain states are all
		* deeper states.
		*/
		drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;
		drv->states[state_count - 1].enter_s2idle =
		sbi_enter_s2idle_domain_idle_state;
		sbi_cpuidle_use_cpuhp = true;

		return 0;
		}

		static int sbi_cpuidle_dt_init_states(struct device *dev,
		struct cpuidle_driver *drv,
		unsigned int cpu,
		unsigned int state_count)
		{
		struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
		struct device_node *state_node;
		struct device_node *cpu_node;
		u32 *states;
		int i, ret;

		cpu_node = of_cpu_device_node_get(cpu);
		if (!cpu_node)
		return -ENODEV;

		states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);
		if (!states) {
		ret = -ENOMEM;
		goto fail;
		}

		/* Parse SBI specific details from state DT nodes */
		for (i = 1; i < state_count; i++) {
		state_node = of_get_cpu_state_node(cpu_node, i - 1);
		if (!state_node)
		break;

		ret = sbi_dt_parse_state_node(state_node, &states[i]);
		of_node_put(state_node);

		if (ret)
		return ret;

		pr_debug("sbi-state %#x index %d\n", states[i], i);
		}
		if (i != state_count) {
		ret = -ENODEV;
		goto fail;
		}

		/* Initialize optional data, used for the hierarchical topology. */
		ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu);
		if (ret < 0)
		return ret;

		/* Store states in the per-cpu struct. */
		data->states = states;

		fail:
		of_node_put(cpu_node);

		return ret;
		}

		static void sbi_cpuidle_deinit_cpu(int cpu)
		{
		struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);

		dt_idle_detach_cpu(data->dev);
		sbi_cpuidle_use_cpuhp = false;
		}

		static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
		{
		struct cpuidle_driver *drv;
		unsigned int state_count = 0;
		int ret = 0;

		drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
		if (!drv)
		return -ENOMEM;

		drv->name = "sbi_cpuidle";
		drv->owner = THIS_MODULE;
		drv->cpumask = (struct cpumask *)cpumask_of(cpu);

		/* RISC-V architectural WFI to be represented as state index 0. */
		drv->states[0].enter = sbi_cpuidle_enter_state;
		drv->states[0].exit_latency = 1;
		drv->states[0].target_residency = 1;
		drv->states[0].power_usage = UINT_MAX;
		strcpy(drv->states[0].name, "WFI");
		strcpy(drv->states[0].desc, "RISC-V WFI");

		/*
		* If no DT idle states are detected (ret == 0) let the driver
		* initialization fail accordingly since there is no reason to
		* initialize the idle driver if only wfi is supported, the
		* default archictectural back-end already executes wfi
		* on idle entry.
		*/
		ret = dt_init_idle_driver(drv, sbi_cpuidle_state_match, 1);
		if (ret <= 0) {
		pr_debug("HART%ld: failed to parse DT idle states\n",
		cpuid_to_hartid_map(cpu));
		return ret ? : -ENODEV;
		}
		state_count = ret + 1; /* Include WFI state as well */

		/* Initialize idle states from DT. */
		ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);
		if (ret) {
		pr_err("HART%ld: failed to init idle states\n",
		cpuid_to_hartid_map(cpu));
		return ret;
		}

		ret = cpuidle_register(drv, NULL);
		if (ret)
		goto deinit;

		cpuidle_cooling_register(drv);

		return 0;
		deinit:
		sbi_cpuidle_deinit_cpu(cpu);
		return ret;
		}

		static void sbi_cpuidle_domain_sync_state(struct device *dev)
		{
		/*
		* All devices have now been attached/probed to the PM domain
		* topology, hence it's fine to allow domain states to be picked.
		*/
		sbi_cpuidle_pd_allow_domain_state = true;
		}

		#ifdef CONFIG_DT_IDLE_GENPD

		static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
		{
		struct genpd_power_state *state = &pd->states[pd->state_idx];
		u32 *pd_state;

		if (!state->data)
		return 0;

		if (!sbi_cpuidle_pd_allow_domain_state)
		return -EBUSY;

		/* OSI mode is enabled, set the corresponding domain state. */
		pd_state = state->data;
		sbi_set_domain_state(*pd_state);

		return 0;
		}

		struct sbi_pd_provider {
		struct list_head link;
		struct device_node *node;
		};

		static LIST_HEAD(sbi_pd_providers);

		static int sbi_pd_init(struct device_node *np)
		{
		struct generic_pm_domain *pd;
		struct sbi_pd_provider *pd_provider;
		struct dev_power_governor *pd_gov;
		int ret = -ENOMEM, state_count = 0;

		pd = dt_idle_pd_alloc(np, sbi_dt_parse_state_node);
		if (!pd)
		goto out;

		pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
		if (!pd_provider)
		goto free_pd;

		pd->flags \|= GENPD_FLAG_IRQ_SAFE \| GENPD_FLAG_CPU_DOMAIN;

		/* Allow power off when OSI is available. */
		if (sbi_cpuidle_use_osi)
		pd->power_off = sbi_cpuidle_pd_power_off;
		else
		pd->flags \|= GENPD_FLAG_ALWAYS_ON;

		/* Use governor for CPU PM domains if it has some states to manage. */
		pd_gov = state_count > 0 ? &pm_domain_cpu_gov : NULL;

		ret = pm_genpd_init(pd, pd_gov, false);
		if (ret)
		goto free_pd_prov;

		ret = of_genpd_add_provider_simple(np, pd);
		if (ret)
		goto remove_pd;

		pd_provider->node = of_node_get(np);
		list_add(&pd_provider->link, &sbi_pd_providers);

		pr_debug("init PM domain %s\n", pd->name);
		return 0;

		remove_pd:
		pm_genpd_remove(pd);
		free_pd_prov:
		kfree(pd_provider);
		free_pd:
		dt_idle_pd_free(pd);
		out:
		pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
		return ret;
		}

		static void sbi_pd_remove(void)
		{
		struct sbi_pd_provider pd_provider, it;
		struct generic_pm_domain *genpd;

		list_for_each_entry_safe(pd_provider, it, &sbi_pd_providers, link) {
		of_genpd_del_provider(pd_provider->node);

		genpd = of_genpd_remove_last(pd_provider->node);
		if (!IS_ERR(genpd))
		kfree(genpd);

		of_node_put(pd_provider->node);
		list_del(&pd_provider->link);
		kfree(pd_provider);
		}
		}

		static int sbi_genpd_probe(struct device_node *np)
		{
		struct device_node *node;
		int ret = 0, pd_count = 0;

		if (!np)
		return -ENODEV;

		/*
		* Parse child nodes for the "#power-domain-cells" property and
		* initialize a genpd/genpd-of-provider pair when it's found.
		*/
		for_each_child_of_node(np, node) {
		if (!of_find_property(node, "#power-domain-cells", NULL))
		continue;

		ret = sbi_pd_init(node);
		if (ret)
		goto put_node;

		pd_count++;
		}

		/* Bail out if not using the hierarchical CPU topology. */
		if (!pd_count)
		goto no_pd;

		/* Link genpd masters/subdomains to model the CPU topology. */
		ret = dt_idle_pd_init_topology(np);
		if (ret)
		goto remove_pd;

		return 0;

		put_node:
		of_node_put(node);
		remove_pd:
		sbi_pd_remove();
		pr_err("failed to create CPU PM domains ret=%d\n", ret);
		no_pd:
		return ret;
		}

		#else

		static inline int sbi_genpd_probe(struct device_node *np)
		{
		return 0;
		}

		#endif

		static int sbi_cpuidle_probe(struct platform_device *pdev)
		{
		int cpu, ret;
		struct cpuidle_driver *drv;
		struct cpuidle_device *dev;
		struct device_node np, pds_node;

		/* Detect OSI support based on CPU DT nodes */
		sbi_cpuidle_use_osi = true;
		for_each_possible_cpu(cpu) {
		np = of_cpu_device_node_get(cpu);
		if (np &&
		of_find_property(np, "power-domains", NULL) &&
		of_find_property(np, "power-domain-names", NULL)) {
		continue;
		} else {
		sbi_cpuidle_use_osi = false;
		break;
		}
		}

		/* Populate generic power domains from DT nodes */
		pds_node = of_find_node_by_path("/cpus/power-domains");
		if (pds_node) {
		ret = sbi_genpd_probe(pds_node);
		of_node_put(pds_node);
		if (ret)
		return ret;
		}

		/* Initialize CPU idle driver for each CPU */
		for_each_possible_cpu(cpu) {
		ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
		if (ret) {
		pr_debug("HART%ld: idle driver init failed\n",
		cpuid_to_hartid_map(cpu));
		goto out_fail;
		}
		}

		/* Setup CPU hotplut notifiers */
		sbi_idle_init_cpuhp();

		pr_info("idle driver registered for all CPUs\n");

		return 0;

		out_fail:
		while (--cpu >= 0) {
		dev = per_cpu(cpuidle_devices, cpu);
		drv = cpuidle_get_cpu_driver(dev);
		cpuidle_unregister(drv);
		sbi_cpuidle_deinit_cpu(cpu);
		}

		return ret;
		}

		static struct platform_driver sbi_cpuidle_driver = {
		.probe = sbi_cpuidle_probe,
		.driver = {
		.name = "sbi-cpuidle",
		.sync_state = sbi_cpuidle_domain_sync_state,
		},
		};

		static int __init sbi_cpuidle_init(void)
		{
		int ret;
		struct platform_device *pdev;

		/*
		* The SBI HSM suspend function is only available when:
		* 1) SBI version is 0.3 or higher
		* 2) SBI HSM extension is available
		*/
		if ((sbi_spec_version < sbi_mk_version(0, 3)) \|\|
		sbi_probe_extension(SBI_EXT_HSM) <= 0) {
		pr_info("HSM suspend not available\n");
		return 0;
		}

		ret = platform_driver_register(&sbi_cpuidle_driver);
		if (ret)
		return ret;

		pdev = platform_device_register_simple("sbi-cpuidle",
		-1, NULL, 0);
		if (IS_ERR(pdev)) {
		platform_driver_unregister(&sbi_cpuidle_driver);
		return PTR_ERR(pdev);
		}

		return 0;
		}
		device_initcall(sbi_cpuidle_init);