drivers/cpuidle/dt_idle_genpd.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * PM domains for CPUs via genpd.
   4  *
   5  * Copyright (C) 2019 Linaro Ltd.
   6  * Author: Ulf Hansson <ulf.hansson@linaro.org>
   7  *
   8  * Copyright (c) 2021 Western Digital Corporation or its affiliates.
   9  * Copyright (c) 2022 Ventana Micro Systems Inc.
  10  */
  11
  12 #define pr_fmt(fmt) "dt-idle-genpd: " fmt
  13
  14 #include <linux/cpu.h>
  15 #include <linux/device.h>
  16 #include <linux/kernel.h>
  17 #include <linux/pm_domain.h>
  18 #include <linux/pm_runtime.h>
  19 #include <linux/slab.h>
  20 #include <linux/string.h>
  21
  22 #include "dt_idle_genpd.h"
  23
  24 static int pd_parse_state_nodes(
  25                         int (*parse_state)(struct device_node *, u32 *),
  26                         struct genpd_power_state *states, int state_count)
  27 {
  28         int i, ret;
  29         u32 state, *state_buf;
  30
  31         for (i = 0; i < state_count; i++) {
  32                 ret = parse_state(to_of_node(states[i].fwnode), &state);
  33                 if (ret)
  34                         goto free_state;
  35
  36                 state_buf = kmalloc(sizeof(u32), GFP_KERNEL);
  37                 if (!state_buf) {
  38                         ret = -ENOMEM;
  39                         goto free_state;
  40                 }
  41                 *state_buf = state;
  42                 states[i].data = state_buf;
  43         }
  44
  45         return 0;
  46
  47 free_state:
  48         i--;
  49         for (; i >= 0; i--)
  50                 kfree(states[i].data);
  51         return ret;
  52 }
  53
  54 static int pd_parse_states(struct device_node *np,
  55                            int (*parse_state)(struct device_node *, u32 *),
  56                            struct genpd_power_state **states,
  57                            int *state_count)
  58 {
  59         int ret;
  60
  61         /* Parse the domain idle states. */
  62         ret = of_genpd_parse_idle_states(np, states, state_count);
  63         if (ret)
  64                 return ret;
  65
  66         /* Fill out the dt specifics for each found state. */
  67         ret = pd_parse_state_nodes(parse_state, *states, *state_count);
  68         if (ret)
  69                 kfree(*states);
  70
  71         return ret;
  72 }
  73
  74 static void pd_free_states(struct genpd_power_state *states,
  75                             unsigned int state_count)
  76 {
  77         int i;
  78
  79         for (i = 0; i < state_count; i++)
  80                 kfree(states[i].data);
  81         kfree(states);
  82 }
  83
  84 void dt_idle_pd_free(struct generic_pm_domain *pd)
  85 {
  86         pd_free_states(pd->states, pd->state_count);
  87         kfree(pd->name);
  88         kfree(pd);
  89 }
  90
  91 struct generic_pm_domain *dt_idle_pd_alloc(struct device_node *np,
  92                         int (*parse_state)(struct device_node *, u32 *))
  93 {
  94         struct generic_pm_domain *pd;
  95         struct genpd_power_state *states = NULL;
  96         int ret, state_count = 0;
  97
  98         pd = kzalloc(sizeof(*pd), GFP_KERNEL);
  99         if (!pd)
 100                 goto out;
 101
 102         pd->name = kasprintf(GFP_KERNEL, "%pOF", np);
 103         if (!pd->name)
 104                 goto free_pd;
 105
 106         /*
 107          * Parse the domain idle states and let genpd manage the state selection
 108          * for those being compatible with "domain-idle-state".
 109          */
 110         ret = pd_parse_states(np, parse_state, &states, &state_count);
 111         if (ret)
 112                 goto free_name;
 113
 114         pd->free_states = pd_free_states;
 115         pd->name = kbasename(pd->name);
 116         pd->states = states;
 117         pd->state_count = state_count;
 118
 119         pr_debug("alloc PM domain %s\n", pd->name);
 120         return pd;
 121
 122 free_name:
 123         kfree(pd->name);
 124 free_pd:
 125         kfree(pd);
 126 out:
 127         pr_err("failed to alloc PM domain %pOF\n", np);
 128         return NULL;
 129 }
 130
 131 int dt_idle_pd_init_topology(struct device_node *np)
 132 {
 133         struct of_phandle_args child, parent;
 134         int ret;
 135
 136         for_each_child_of_node_scoped(np, node) {
 137                 if (of_parse_phandle_with_args(node, "power-domains",
 138                                         "#power-domain-cells", 0, &parent))
 139                         continue;
 140
 141                 child.np = node;
 142                 child.args_count = 0;
 143                 ret = of_genpd_add_subdomain(&parent, &child);
 144                 of_node_put(parent.np);
 145                 if (ret)
 146                         return ret;
 147         }
 148
 149         return 0;
 150 }
 151
 152 int dt_idle_pd_remove_topology(struct device_node *np)
 153 {
 154         struct of_phandle_args child, parent;
 155         int ret;
 156
 157         for_each_child_of_node_scoped(np, node) {
 158                 if (of_parse_phandle_with_args(node, "power-domains",
 159                                         "#power-domain-cells", 0, &parent))
 160                         continue;
 161
 162                 child.np = node;
 163                 child.args_count = 0;
 164                 ret = of_genpd_remove_subdomain(&parent, &child);
 165                 of_node_put(parent.np);
 166                 if (ret)
 167                         return ret;
 168         }
 169
 170         return 0;
 171 }
 172
 173 struct device *dt_idle_attach_cpu(int cpu, const char *name)
 174 {
 175         struct device *dev;
 176
 177         dev = dev_pm_domain_attach_by_name(get_cpu_device(cpu), name);
 178         if (IS_ERR_OR_NULL(dev))
 179                 return dev;
 180
 181         pm_runtime_irq_safe(dev);
 182         if (cpu_online(cpu))
 183                 pm_runtime_get_sync(dev);
 184
 185         dev_pm_syscore_device(dev, true);
 186
 187         return dev;
 188 }
 189
 190 void dt_idle_detach_cpu(struct device *dev)
 191 {
 192         if (IS_ERR_OR_NULL(dev))
 193                 return;
 194
 195         dev_pm_domain_detach(dev, false);
 196 }