drivers/cpuidle/dt_idle_genpd.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * PM domains for CPUs via genpd.
0004  *
0005  * Copyright (C) 2019 Linaro Ltd.
0006  * Author: Ulf Hansson <ulf.hansson@linaro.org>
0007  *
0008  * Copyright (c) 2021 Western Digital Corporation or its affiliates.
0009  * Copyright (c) 2022 Ventana Micro Systems Inc.
0010  */
0011
0012 #define pr_fmt(fmt) "dt-idle-genpd: " fmt
0013
0014 #include <linux/cpu.h>
0015 #include <linux/device.h>
0016 #include <linux/kernel.h>
0017 #include <linux/pm_domain.h>
0018 #include <linux/pm_runtime.h>
0019 #include <linux/slab.h>
0020 #include <linux/string.h>
0021
0022 #include "dt_idle_genpd.h"
0023
0024 static int pd_parse_state_nodes(
0025             int (*parse_state)(struct device_node *, u32 *),
0026             struct genpd_power_state *states, int state_count)
0027 {
0028     int i, ret;
0029     u32 state, *state_buf;
0030
0031     for (i = 0; i < state_count; i++) {
0032         ret = parse_state(to_of_node(states[i].fwnode), &state);
0033         if (ret)
0034             goto free_state;
0035
0036         state_buf = kmalloc(sizeof(u32), GFP_KERNEL);
0037         if (!state_buf) {
0038             ret = -ENOMEM;
0039             goto free_state;
0040         }
0041         *state_buf = state;
0042         states[i].data = state_buf;
0043     }
0044
0045     return 0;
0046
0047 free_state:
0048     i--;
0049     for (; i >= 0; i--)
0050         kfree(states[i].data);
0051     return ret;
0052 }
0053
0054 static int pd_parse_states(struct device_node *np,
0055                int (*parse_state)(struct device_node *, u32 *),
0056                struct genpd_power_state **states,
0057                int *state_count)
0058 {
0059     int ret;
0060
0061     /* Parse the domain idle states. */
0062     ret = of_genpd_parse_idle_states(np, states, state_count);
0063     if (ret)
0064         return ret;
0065
0066     /* Fill out the dt specifics for each found state. */
0067     ret = pd_parse_state_nodes(parse_state, *states, *state_count);
0068     if (ret)
0069         kfree(*states);
0070
0071     return ret;
0072 }
0073
0074 static void pd_free_states(struct genpd_power_state *states,
0075                 unsigned int state_count)
0076 {
0077     int i;
0078
0079     for (i = 0; i < state_count; i++)
0080         kfree(states[i].data);
0081     kfree(states);
0082 }
0083
0084 void dt_idle_pd_free(struct generic_pm_domain *pd)
0085 {
0086     pd_free_states(pd->states, pd->state_count);
0087     kfree(pd->name);
0088     kfree(pd);
0089 }
0090
0091 struct generic_pm_domain *dt_idle_pd_alloc(struct device_node *np,
0092             int (*parse_state)(struct device_node *, u32 *))
0093 {
0094     struct generic_pm_domain *pd;
0095     struct genpd_power_state *states = NULL;
0096     int ret, state_count = 0;
0097
0098     pd = kzalloc(sizeof(*pd), GFP_KERNEL);
0099     if (!pd)
0100         goto out;
0101
0102     pd->name = kasprintf(GFP_KERNEL, "%pOF", np);
0103     if (!pd->name)
0104         goto free_pd;
0105
0106     /*
0107      * Parse the domain idle states and let genpd manage the state selection
0108      * for those being compatible with "domain-idle-state".
0109      */
0110     ret = pd_parse_states(np, parse_state, &states, &state_count);
0111     if (ret)
0112         goto free_name;
0113
0114     pd->free_states = pd_free_states;
0115     pd->name = kbasename(pd->name);
0116     pd->states = states;
0117     pd->state_count = state_count;
0118
0119     pr_debug("alloc PM domain %s\n", pd->name);
0120     return pd;
0121
0122 free_name:
0123     kfree(pd->name);
0124 free_pd:
0125     kfree(pd);
0126 out:
0127     pr_err("failed to alloc PM domain %pOF\n", np);
0128     return NULL;
0129 }
0130
0131 int dt_idle_pd_init_topology(struct device_node *np)
0132 {
0133     struct device_node *node;
0134     struct of_phandle_args child, parent;
0135     int ret;
0136
0137     for_each_child_of_node(np, node) {
0138         if (of_parse_phandle_with_args(node, "power-domains",
0139                     "#power-domain-cells", 0, &parent))
0140             continue;
0141
0142         child.np = node;
0143         child.args_count = 0;
0144         ret = of_genpd_add_subdomain(&parent, &child);
0145         of_node_put(parent.np);
0146         if (ret) {
0147             of_node_put(node);
0148             return ret;
0149         }
0150     }
0151
0152     return 0;
0153 }
0154
0155 struct device *dt_idle_attach_cpu(int cpu, const char *name)
0156 {
0157     struct device *dev;
0158
0159     dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), name);
0160     if (IS_ERR_OR_NULL(dev))
0161         return dev;
0162
0163     pm_runtime_irq_safe(dev);
0164     if (cpu_online(cpu))
0165         pm_runtime_get_sync(dev);
0166
0167     dev_pm_syscore_device(dev, true);
0168
0169     return dev;
0170 }
0171
0172 void dt_idle_detach_cpu(struct device *dev)
0173 {
0174     if (IS_ERR_OR_NULL(dev))
0175         return;
0176
0177     dev_pm_domain_detach(dev, false);
0178 }