[linux-block.git] / drivers / cpuidle / cpuidle-riscv-sbi.c

// 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/smp.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;

	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 = pd->states ? &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);
Commit	Line	Data
6abf32f1 AP	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/*
	3	* RISC-V SBI CPU idle driver.
	4	*
	5	* Copyright (c) 2021 Western Digital Corporation or its affiliates.
	6	* Copyright (c) 2022 Ventana Micro Systems Inc.
	7	*/
	8
	9	#define pr_fmt(fmt) "cpuidle-riscv-sbi: " fmt
	10
	11	#include <linux/cpuidle.h>
	12	#include <linux/cpumask.h>
	13	#include <linux/cpu_pm.h>
	14	#include <linux/cpu_cooling.h>
	15	#include <linux/kernel.h>
	16	#include <linux/module.h>
	17	#include <linux/of.h>
	18	#include <linux/of_device.h>
	19	#include <linux/slab.h>
	20	#include <linux/platform_device.h>
	21	#include <linux/pm_domain.h>
	22	#include <linux/pm_runtime.h>
	23	#include <asm/cpuidle.h>
	24	#include <asm/sbi.h>
f81f7861	25	#include <asm/smp.h>
6abf32f1 AP	26	#include <asm/suspend.h>
	27
	28	#include "dt_idle_states.h"
	29	#include "dt_idle_genpd.h"
	30
	31	struct sbi_cpuidle_data {
	32	u32 *states;
	33	struct device *dev;
	34	};
	35
	36	struct sbi_domain_state {
	37	bool available;
	38	u32 state;
	39	};
	40
	41	static DEFINE_PER_CPU_READ_MOSTLY(struct sbi_cpuidle_data, sbi_cpuidle_data);
	42	static DEFINE_PER_CPU(struct sbi_domain_state, domain_state);
	43	static bool sbi_cpuidle_use_osi;
	44	static bool sbi_cpuidle_use_cpuhp;
	45	static bool sbi_cpuidle_pd_allow_domain_state;
	46
	47	static inline void sbi_set_domain_state(u32 state)
	48	{
	49	struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
	50
	51	data->available = true;
	52	data->state = state;
	53	}
	54
	55	static inline u32 sbi_get_domain_state(void)
	56	{
	57	struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
	58
	59	return data->state;
	60	}
	61
	62	static inline void sbi_clear_domain_state(void)
	63	{
	64	struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
	65
	66	data->available = false;
	67	}
	68
	69	static inline bool sbi_is_domain_state_available(void)
	70	{
	71	struct sbi_domain_state *data = this_cpu_ptr(&domain_state);
	72
	73	return data->available;
	74	}
	75
	76	static int sbi_suspend_finisher(unsigned long suspend_type,
	77	unsigned long resume_addr,
	78	unsigned long opaque)
	79	{
	80	struct sbiret ret;
	81
	82	ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
	83	suspend_type, resume_addr, opaque, 0, 0, 0);
	84
	85	return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
	86	}
	87
	88	static int sbi_suspend(u32 state)
	89	{
90	if (state & SBI_HSM_SUSP_NON_RET_BIT)
91	return cpu_suspend(state, sbi_suspend_finisher);
92	else
93	return sbi_suspend_finisher(state, 0, 0);
94	}
95
96	static int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
97	struct cpuidle_driver *drv, int idx)
98	{
99	u32 *states = __this_cpu_read(sbi_cpuidle_data.states);
100
101	return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, states[idx]);
102	}
103
104	static int __sbi_enter_domain_idle_state(struct cpuidle_device *dev,
105	struct cpuidle_driver *drv, int idx,
106	bool s2idle)
107	{
108	struct sbi_cpuidle_data *data = this_cpu_ptr(&sbi_cpuidle_data);
109	u32 *states = data->states;
110	struct device *pd_dev = data->dev;
111	u32 state;
112	int ret;
113
114	ret = cpu_pm_enter();
115	if (ret)
116	return -1;
117
118	/* Do runtime PM to manage a hierarchical CPU toplogy. */
119	rcu_irq_enter_irqson();
120	if (s2idle)
121	dev_pm_genpd_suspend(pd_dev);
122	else
123	pm_runtime_put_sync_suspend(pd_dev);
124	rcu_irq_exit_irqson();
125
126	if (sbi_is_domain_state_available())
127	state = sbi_get_domain_state();
128	else
129	state = states[idx];
130
131	ret = sbi_suspend(state) ? -1 : idx;
132
133	rcu_irq_enter_irqson();
134	if (s2idle)
135	dev_pm_genpd_resume(pd_dev);
136	else
137	pm_runtime_get_sync(pd_dev);
138	rcu_irq_exit_irqson();
139
140	cpu_pm_exit();
141
142	/* Clear the domain state to start fresh when back from idle. */
143	sbi_clear_domain_state();
144	return ret;
145	}
146
147	static int sbi_enter_domain_idle_state(struct cpuidle_device *dev,
148	struct cpuidle_driver *drv, int idx)
149	{
150	return __sbi_enter_domain_idle_state(dev, drv, idx, false);
151	}
152
153	static int sbi_enter_s2idle_domain_idle_state(struct cpuidle_device *dev,
154	struct cpuidle_driver *drv,
155	int idx)
156	{
157	return __sbi_enter_domain_idle_state(dev, drv, idx, true);
158	}
159
160	static int sbi_cpuidle_cpuhp_up(unsigned int cpu)
161	{
162	struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
163
164	if (pd_dev)
165	pm_runtime_get_sync(pd_dev);
166
167	return 0;
168	}
169
170	static int sbi_cpuidle_cpuhp_down(unsigned int cpu)
171	{
172	struct device *pd_dev = __this_cpu_read(sbi_cpuidle_data.dev);
173
174	if (pd_dev) {
175	pm_runtime_put_sync(pd_dev);
176	/* Clear domain state to start fresh at next online. */
177	sbi_clear_domain_state();
178	}
179
180	return 0;
181	}
182
183	static void sbi_idle_init_cpuhp(void)
184	{
185	int err;
186
187	if (!sbi_cpuidle_use_cpuhp)
188	return;
189
190	err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING,
191	"cpuidle/sbi:online",
192	sbi_cpuidle_cpuhp_up,
193	sbi_cpuidle_cpuhp_down);
194	if (err)
195	pr_warn("Failed %d while setup cpuhp state\n", err);
196	}
197
198	static const struct of_device_id sbi_cpuidle_state_match[] = {
199	{ .compatible = "riscv,idle-state",
200	.data = sbi_cpuidle_enter_state },
201	{ },
202	};
203
204	static bool sbi_suspend_state_is_valid(u32 state)
205	{
206	if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
207	state < SBI_HSM_SUSPEND_RET_PLATFORM)
208	return false;
209	if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
210	state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
211	return false;
212	return true;
213	}
214
215	static int sbi_dt_parse_state_node(struct device_node np, u32 state)
216	{
217	int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);
218
219	if (err) {
220	pr_warn("%pOF missing riscv,sbi-suspend-param property\n", np);
221	return err;
222	}
223
224	if (!sbi_suspend_state_is_valid(*state)) {
225	pr_warn("Invalid SBI suspend state %#x\n", *state);
226	return -EINVAL;
227	}
228
229	return 0;
230	}
231
232	static int sbi_dt_cpu_init_topology(struct cpuidle_driver *drv,
233	struct sbi_cpuidle_data *data,
234	unsigned int state_count, int cpu)
235	{
236	/* Currently limit the hierarchical topology to be used in OSI mode. */
237	if (!sbi_cpuidle_use_osi)
238	return 0;
239
240	data->dev = dt_idle_attach_cpu(cpu, "sbi");
241	if (IS_ERR_OR_NULL(data->dev))
242	return PTR_ERR_OR_ZERO(data->dev);
243
244	/*
245	* Using the deepest state for the CPU to trigger a potential selection
246	* of a shared state for the domain, assumes the domain states are all
247	* deeper states.
248	*/
249	drv->states[state_count - 1].enter = sbi_enter_domain_idle_state;
250	drv->states[state_count - 1].enter_s2idle =
251	sbi_enter_s2idle_domain_idle_state;
252	sbi_cpuidle_use_cpuhp = true;
253
254	return 0;
255	}
256
257	static int sbi_cpuidle_dt_init_states(struct device *dev,
258	struct cpuidle_driver *drv,
259	unsigned int cpu,
260	unsigned int state_count)
261	{
262	struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
263	struct device_node *state_node;
264	struct device_node *cpu_node;
265	u32 *states;
266	int i, ret;
267
268	cpu_node = of_cpu_device_node_get(cpu);
269	if (!cpu_node)
270	return -ENODEV;
271
272	states = devm_kcalloc(dev, state_count, sizeof(*states), GFP_KERNEL);
273	if (!states) {
274	ret = -ENOMEM;
275	goto fail;
276	}
277
278	/* Parse SBI specific details from state DT nodes */
279	for (i = 1; i < state_count; i++) {
280	state_node = of_get_cpu_state_node(cpu_node, i - 1);
281	if (!state_node)
282	break;
283
284	ret = sbi_dt_parse_state_node(state_node, &states[i]);
285	of_node_put(state_node);
286
287	if (ret)
288	return ret;
289
290	pr_debug("sbi-state %#x index %d\n", states[i], i);
291	}
292	if (i != state_count) {
293	ret = -ENODEV;
294	goto fail;
295	}
296
297	/* Initialize optional data, used for the hierarchical topology. */
298	ret = sbi_dt_cpu_init_topology(drv, data, state_count, cpu);
299	if (ret < 0)
300	return ret;
301
302	/* Store states in the per-cpu struct. */
303	data->states = states;
304
305	fail:
306	of_node_put(cpu_node);
307
308	return ret;
309	}
310
311	static void sbi_cpuidle_deinit_cpu(int cpu)
312	{
313	struct sbi_cpuidle_data *data = per_cpu_ptr(&sbi_cpuidle_data, cpu);
314
315	dt_idle_detach_cpu(data->dev);
316	sbi_cpuidle_use_cpuhp = false;
317	}
318
319	static int sbi_cpuidle_init_cpu(struct device *dev, int cpu)
320	{
321	struct cpuidle_driver *drv;
322	unsigned int state_count = 0;
323	int ret = 0;
324
325	drv = devm_kzalloc(dev, sizeof(*drv), GFP_KERNEL);
326	if (!drv)
327	return -ENOMEM;
328
329	drv->name = "sbi_cpuidle";
330	drv->owner = THIS_MODULE;
331	drv->cpumask = (struct cpumask *)cpumask_of(cpu);
332
333	/* RISC-V architectural WFI to be represented as state index 0. */
334	drv->states[0].enter = sbi_cpuidle_enter_state;
335	drv->states[0].exit_latency = 1;
336	drv->states[0].target_residency = 1;
337	drv->states[0].power_usage = UINT_MAX;
338	strcpy(drv->states[0].name, "WFI");
339	strcpy(drv->states[0].desc, "RISC-V WFI");
340
341	/*
342	* If no DT idle states are detected (ret == 0) let the driver
343	* initialization fail accordingly since there is no reason to
344	* initialize the idle driver if only wfi is supported, the
345	* default archictectural back-end already executes wfi
346	* on idle entry.
347	*/
348	ret = dt_init_idle_driver(drv, sbi_cpuidle_state_match, 1);
349	if (ret <= 0) {
350	pr_debug("HART%ld: failed to parse DT idle states\n",
351	cpuid_to_hartid_map(cpu));
352	return ret ? : -ENODEV;
353	}
354	state_count = ret + 1; /* Include WFI state as well */
355
356	/* Initialize idle states from DT. */
357	ret = sbi_cpuidle_dt_init_states(dev, drv, cpu, state_count);
358	if (ret) {
359	pr_err("HART%ld: failed to init idle states\n",
360	cpuid_to_hartid_map(cpu));
361	return ret;
362	}
363
364	ret = cpuidle_register(drv, NULL);
365	if (ret)
366	goto deinit;
367
368	cpuidle_cooling_register(drv);
369
370	return 0;
371	deinit:
372	sbi_cpuidle_deinit_cpu(cpu);
373	return ret;
374	}
375
376	static void sbi_cpuidle_domain_sync_state(struct device *dev)
377	{
378	/*
379	* All devices have now been attached/probed to the PM domain
380	* topology, hence it's fine to allow domain states to be picked.
381	*/
382	sbi_cpuidle_pd_allow_domain_state = true;
383	}
384
385	#ifdef CONFIG_DT_IDLE_GENPD
386
387	static int sbi_cpuidle_pd_power_off(struct generic_pm_domain *pd)
388	{
389	struct genpd_power_state *state = &pd->states[pd->state_idx];
390	u32 *pd_state;
391
392	if (!state->data)
393	return 0;
394
395	if (!sbi_cpuidle_pd_allow_domain_state)
396	return -EBUSY;
397
398	/* OSI mode is enabled, set the corresponding domain state. */
399	pd_state = state->data;
400	sbi_set_domain_state(*pd_state);
401
402	return 0;
403	}
404
405	struct sbi_pd_provider {
406	struct list_head link;
407	struct device_node *node;
408	};
409
410	static LIST_HEAD(sbi_pd_providers);
411
412	static int sbi_pd_init(struct device_node *np)
413	{
414	struct generic_pm_domain *pd;
415	struct sbi_pd_provider *pd_provider;
416	struct dev_power_governor *pd_gov;
a6653fb5	417	int ret = -ENOMEM;
6abf32f1 AP	418
	419	pd = dt_idle_pd_alloc(np, sbi_dt_parse_state_node);
	420	if (!pd)
	421	goto out;
	422
	423	pd_provider = kzalloc(sizeof(*pd_provider), GFP_KERNEL);
	424	if (!pd_provider)
	425	goto free_pd;
	426
	427	pd->flags \|= GENPD_FLAG_IRQ_SAFE \| GENPD_FLAG_CPU_DOMAIN;
	428
	429	/* Allow power off when OSI is available. */
	430	if (sbi_cpuidle_use_osi)
	431	pd->power_off = sbi_cpuidle_pd_power_off;
	432	else
	433	pd->flags \|= GENPD_FLAG_ALWAYS_ON;
	434
	435	/* Use governor for CPU PM domains if it has some states to manage. */
a6653fb5	436	pd_gov = pd->states ? &pm_domain_cpu_gov : NULL;
6abf32f1 AP	437
	438	ret = pm_genpd_init(pd, pd_gov, false);
	439	if (ret)
	440	goto free_pd_prov;
	441
	442	ret = of_genpd_add_provider_simple(np, pd);
	443	if (ret)
	444	goto remove_pd;
	445
	446	pd_provider->node = of_node_get(np);
	447	list_add(&pd_provider->link, &sbi_pd_providers);
	448
	449	pr_debug("init PM domain %s\n", pd->name);
	450	return 0;
	451
	452	remove_pd:
	453	pm_genpd_remove(pd);
	454	free_pd_prov:
	455	kfree(pd_provider);
	456	free_pd:
	457	dt_idle_pd_free(pd);
	458	out:
	459	pr_err("failed to init PM domain ret=%d %pOF\n", ret, np);
	460	return ret;
	461	}
	462
	463	static void sbi_pd_remove(void)
	464	{
	465	struct sbi_pd_provider pd_provider, it;
	466	struct generic_pm_domain *genpd;
	467
	468	list_for_each_entry_safe(pd_provider, it, &sbi_pd_providers, link) {
	469	of_genpd_del_provider(pd_provider->node);
	470
	471	genpd = of_genpd_remove_last(pd_provider->node);
	472	if (!IS_ERR(genpd))
	473	kfree(genpd);
	474
	475	of_node_put(pd_provider->node);
	476	list_del(&pd_provider->link);
	477	kfree(pd_provider);
	478	}
	479	}
	480
	481	static int sbi_genpd_probe(struct device_node *np)
	482	{
	483	struct device_node *node;
	484	int ret = 0, pd_count = 0;
	485
	486	if (!np)
	487	return -ENODEV;
	488
	489	/*
	490	* Parse child nodes for the "#power-domain-cells" property and
	491	* initialize a genpd/genpd-of-provider pair when it's found.
	492	*/
	493	for_each_child_of_node(np, node) {
	494	if (!of_find_property(node, "#power-domain-cells", NULL))
	495	continue;
	496
	497	ret = sbi_pd_init(node);
	498	if (ret)
	499	goto put_node;
	500
501	pd_count++;
502	}
503
504	/* Bail out if not using the hierarchical CPU topology. */
505	if (!pd_count)
506	goto no_pd;
507
508	/* Link genpd masters/subdomains to model the CPU topology. */
509	ret = dt_idle_pd_init_topology(np);
510	if (ret)
511	goto remove_pd;
512
513	return 0;
514
515	put_node:
516	of_node_put(node);
517	remove_pd:
518	sbi_pd_remove();
519	pr_err("failed to create CPU PM domains ret=%d\n", ret);
520	no_pd:
521	return ret;
522	}
523
524	#else
525
526	static inline int sbi_genpd_probe(struct device_node *np)
527	{
528	return 0;
529	}
530
531	#endif
532
533	static int sbi_cpuidle_probe(struct platform_device *pdev)
534	{
535	int cpu, ret;
536	struct cpuidle_driver *drv;
537	struct cpuidle_device *dev;
538	struct device_node np, pds_node;
539
540	/* Detect OSI support based on CPU DT nodes */
541	sbi_cpuidle_use_osi = true;
542	for_each_possible_cpu(cpu) {
543	np = of_cpu_device_node_get(cpu);
544	if (np &&
545	of_find_property(np, "power-domains", NULL) &&
546	of_find_property(np, "power-domain-names", NULL)) {
547	continue;
548	} else {
549	sbi_cpuidle_use_osi = false;
550	break;
551	}
552	}
553
554	/* Populate generic power domains from DT nodes */
555	pds_node = of_find_node_by_path("/cpus/power-domains");
556	if (pds_node) {
557	ret = sbi_genpd_probe(pds_node);
558	of_node_put(pds_node);
559	if (ret)
560	return ret;
561	}
562
563	/* Initialize CPU idle driver for each CPU */
564	for_each_possible_cpu(cpu) {
565	ret = sbi_cpuidle_init_cpu(&pdev->dev, cpu);
566	if (ret) {
567	pr_debug("HART%ld: idle driver init failed\n",
568	cpuid_to_hartid_map(cpu));
569	goto out_fail;
570	}
571	}
572
573	/* Setup CPU hotplut notifiers */
574	sbi_idle_init_cpuhp();
575
576	pr_info("idle driver registered for all CPUs\n");
577
578	return 0;
579
580	out_fail:
581	while (--cpu >= 0) {
582	dev = per_cpu(cpuidle_devices, cpu);
583	drv = cpuidle_get_cpu_driver(dev);
584	cpuidle_unregister(drv);
585	sbi_cpuidle_deinit_cpu(cpu);
586	}
587
588	return ret;
589	}
590
591	static struct platform_driver sbi_cpuidle_driver = {
592	.probe = sbi_cpuidle_probe,
593	.driver = {
594	.name = "sbi-cpuidle",
595	.sync_state = sbi_cpuidle_domain_sync_state,
596	},
597	};
598
599	static int __init sbi_cpuidle_init(void)
600	{
601	int ret;
602	struct platform_device *pdev;
603
604	/*
605	* The SBI HSM suspend function is only available when:
606	* 1) SBI version is 0.3 or higher
607	* 2) SBI HSM extension is available
608	*/
609	if ((sbi_spec_version < sbi_mk_version(0, 3)) \|\|
610	sbi_probe_extension(SBI_EXT_HSM) <= 0) {
611	pr_info("HSM suspend not available\n");
612	return 0;
613	}
614
615	ret = platform_driver_register(&sbi_cpuidle_driver);
616	if (ret)
617	return ret;
618
619	pdev = platform_device_register_simple("sbi-cpuidle",
620	-1, NULL, 0);
621	if (IS_ERR(pdev)) {
622	platform_driver_unregister(&sbi_cpuidle_driver);
623	return PTR_ERR(pdev);
624	}
625
626	return 0;
627	}
628	device_initcall(sbi_cpuidle_init);