arch/arm/mach-exynos/pm_domains.c

   1 /*
   2  * Exynos Generic power domain support.
   3  *
   4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5  *              http://www.samsung.com
   6  *
   7  * Implementation of Exynos specific power domain control which is used in
   8  * conjunction with runtime-pm. Support for both device-tree and non-device-tree
   9  * based power domain support is included.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14 */
  15
  16 #include <linux/io.h>
  17 #include <linux/err.h>
  18 #include <linux/slab.h>
  19 #include <linux/pm_domain.h>
  20 #include <linux/delay.h>
  21 #include <linux/of_address.h>
  22 #include <linux/of_platform.h>
  23 #include <linux/sched.h>
  24
  25 #include "regs-pmu.h"
  26
  27 /*
  28  * Exynos specific wrapper around the generic power domain
  29  */
  30 struct exynos_pm_domain {
  31         void __iomem *base;
  32         char const *name;
  33         bool is_off;
  34         struct generic_pm_domain pd;
  35 };
  36
  37 static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
  38 {
  39         struct exynos_pm_domain *pd;
  40         void __iomem *base;
  41         u32 timeout, pwr;
  42         char *op;
  43
  44         pd = container_of(domain, struct exynos_pm_domain, pd);
  45         base = pd->base;
  46
  47         pwr = power_on ? S5P_INT_LOCAL_PWR_EN : 0;
  48         __raw_writel(pwr, base);
  49
  50         /* Wait max 1ms */
  51         timeout = 10;
  52
  53         while ((__raw_readl(base + 0x4) & S5P_INT_LOCAL_PWR_EN) != pwr) {
  54                 if (!timeout) {
  55                         op = (power_on) ? "enable" : "disable";
  56                         pr_err("Power domain %s %s failed\n", domain->name, op);
  57                         return -ETIMEDOUT;
  58                 }
  59                 timeout--;
  60                 cpu_relax();
  61                 usleep_range(80, 100);
  62         }
  63         return 0;
  64 }
  65
  66 static int exynos_pd_power_on(struct generic_pm_domain *domain)
  67 {
  68         return exynos_pd_power(domain, true);
  69 }
  70
  71 static int exynos_pd_power_off(struct generic_pm_domain *domain)
  72 {
  73         return exynos_pd_power(domain, false);
  74 }
  75
  76 static void exynos_add_device_to_domain(struct exynos_pm_domain *pd,
  77                                          struct device *dev)
  78 {
  79         int ret;
  80
  81         dev_dbg(dev, "adding to power domain %s\n", pd->pd.name);
  82
  83         while (1) {
  84                 ret = pm_genpd_add_device(&pd->pd, dev);
  85                 if (ret != -EAGAIN)
  86                         break;
  87                 cond_resched();
  88         }
  89
  90         pm_genpd_dev_need_restore(dev, true);
  91 }
  92
  93 static void exynos_remove_device_from_domain(struct device *dev)
  94 {
  95         struct generic_pm_domain *genpd = dev_to_genpd(dev);
  96         int ret;
  97
  98         dev_dbg(dev, "removing from power domain %s\n", genpd->name);
  99
 100         while (1) {
 101                 ret = pm_genpd_remove_device(genpd, dev);
 102                 if (ret != -EAGAIN)
 103                         break;
 104                 cond_resched();
 105         }
 106 }
 107
 108 static void exynos_read_domain_from_dt(struct device *dev)
 109 {
 110         struct platform_device *pd_pdev;
 111         struct exynos_pm_domain *pd;
 112         struct device_node *node;
 113
 114         node = of_parse_phandle(dev->of_node, "samsung,power-domain", 0);
 115         if (!node)
 116                 return;
 117         pd_pdev = of_find_device_by_node(node);
 118         if (!pd_pdev)
 119                 return;
 120         pd = platform_get_drvdata(pd_pdev);
 121         exynos_add_device_to_domain(pd, dev);
 122 }
 123
 124 static int exynos_pm_notifier_call(struct notifier_block *nb,
 125                                     unsigned long event, void *data)
 126 {
 127         struct device *dev = data;
 128
 129         switch (event) {
 130         case BUS_NOTIFY_BIND_DRIVER:
 131                 if (dev->of_node)
 132                         exynos_read_domain_from_dt(dev);
 133
 134                 break;
 135
 136         case BUS_NOTIFY_UNBOUND_DRIVER:
 137                 exynos_remove_device_from_domain(dev);
 138
 139                 break;
 140         }
 141         return NOTIFY_DONE;
 142 }
 143
 144 static struct notifier_block platform_nb = {
 145         .notifier_call = exynos_pm_notifier_call,
 146 };
 147
 148 static __init int exynos4_pm_init_power_domain(void)
 149 {
 150         struct platform_device *pdev;
 151         struct device_node *np;
 152
 153         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
 154                 struct exynos_pm_domain *pd;
 155                 int on;
 156
 157                 pdev = of_find_device_by_node(np);
 158
 159                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 160                 if (!pd) {
 161                         pr_err("%s: failed to allocate memory for domain\n",
 162                                         __func__);
 163                         return -ENOMEM;
 164                 }
 165
 166                 pd->pd.name = kstrdup(np->name, GFP_KERNEL);
 167                 pd->name = pd->pd.name;
 168                 pd->base = of_iomap(np, 0);
 169                 pd->pd.power_off = exynos_pd_power_off;
 170                 pd->pd.power_on = exynos_pd_power_on;
 171                 pd->pd.of_node = np;
 172
 173                 platform_set_drvdata(pdev, pd);
 174
 175                 on = __raw_readl(pd->base + 0x4) & S5P_INT_LOCAL_PWR_EN;
 176
 177                 pm_genpd_init(&pd->pd, NULL, !on);
 178         }
 179
 180         bus_register_notifier(&platform_bus_type, &platform_nb);
 181
 182         return 0;
 183 }
 184 arch_initcall(exynos4_pm_init_power_domain);