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/clk.h>
  21 #include <linux/delay.h>
  22 #include <linux/of_address.h>
  23 #include <linux/of_platform.h>
  24 #include <linux/sched.h>
  25
  26 #include "regs-pmu.h"
  27
  28 #define MAX_CLK_PER_DOMAIN      4
  29
  30 /*
  31  * Exynos specific wrapper around the generic power domain
  32  */
  33 struct exynos_pm_domain {
  34         void __iomem *base;
  35         char const *name;
  36         bool is_off;
  37         struct generic_pm_domain pd;
  38         struct clk *oscclk;
  39         struct clk *clk[MAX_CLK_PER_DOMAIN];
  40         struct clk *pclk[MAX_CLK_PER_DOMAIN];
  41 };
  42
  43 static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
  44 {
  45         struct exynos_pm_domain *pd;
  46         void __iomem *base;
  47         u32 timeout, pwr;
  48         char *op;
  49
  50         pd = container_of(domain, struct exynos_pm_domain, pd);
  51         base = pd->base;
  52
  53         /* Set oscclk before powering off a domain*/
  54         if (!power_on) {
  55                 int i;
  56
  57                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  58                         if (IS_ERR(pd->clk[i]))
  59                                 break;
  60                         if (clk_set_parent(pd->clk[i], pd->oscclk))
  61                                 pr_err("%s: error setting oscclk as parent to clock %d\n",
  62                                                 pd->name, i);
  63                 }
  64         }
  65
  66         pwr = power_on ? S5P_INT_LOCAL_PWR_EN : 0;
  67         __raw_writel(pwr, base);
  68
  69         /* Wait max 1ms */
  70         timeout = 10;
  71
  72         while ((__raw_readl(base + 0x4) & S5P_INT_LOCAL_PWR_EN) != pwr) {
  73                 if (!timeout) {
  74                         op = (power_on) ? "enable" : "disable";
  75                         pr_err("Power domain %s %s failed\n", domain->name, op);
  76                         return -ETIMEDOUT;
  77                 }
  78                 timeout--;
  79                 cpu_relax();
  80                 usleep_range(80, 100);
  81         }
  82
  83         /* Restore clocks after powering on a domain*/
  84         if (power_on) {
  85                 int i;
  86
  87                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  88                         if (IS_ERR(pd->clk[i]))
  89                                 break;
  90                         if (clk_set_parent(pd->clk[i], pd->pclk[i]))
  91                                 pr_err("%s: error setting parent to clock%d\n",
  92                                                 pd->name, i);
  93                 }
  94         }
  95
  96         return 0;
  97 }
  98
  99 static int exynos_pd_power_on(struct generic_pm_domain *domain)
 100 {
 101         return exynos_pd_power(domain, true);
 102 }
 103
 104 static int exynos_pd_power_off(struct generic_pm_domain *domain)
 105 {
 106         return exynos_pd_power(domain, false);
 107 }
 108
 109 static void exynos_add_device_to_domain(struct exynos_pm_domain *pd,
 110                                          struct device *dev)
 111 {
 112         int ret;
 113
 114         dev_dbg(dev, "adding to power domain %s\n", pd->pd.name);
 115
 116         while (1) {
 117                 ret = pm_genpd_add_device(&pd->pd, dev);
 118                 if (ret != -EAGAIN)
 119                         break;
 120                 cond_resched();
 121         }
 122
 123         pm_genpd_dev_need_restore(dev, true);
 124 }
 125
 126 static void exynos_remove_device_from_domain(struct device *dev)
 127 {
 128         struct generic_pm_domain *genpd = dev_to_genpd(dev);
 129         int ret;
 130
 131         dev_dbg(dev, "removing from power domain %s\n", genpd->name);
 132
 133         while (1) {
 134                 ret = pm_genpd_remove_device(genpd, dev);
 135                 if (ret != -EAGAIN)
 136                         break;
 137                 cond_resched();
 138         }
 139 }
 140
 141 static void exynos_read_domain_from_dt(struct device *dev)
 142 {
 143         struct platform_device *pd_pdev;
 144         struct exynos_pm_domain *pd;
 145         struct device_node *node;
 146
 147         node = of_parse_phandle(dev->of_node, "samsung,power-domain", 0);
 148         if (!node)
 149                 return;
 150         pd_pdev = of_find_device_by_node(node);
 151         if (!pd_pdev)
 152                 return;
 153         pd = platform_get_drvdata(pd_pdev);
 154         exynos_add_device_to_domain(pd, dev);
 155 }
 156
 157 static int exynos_pm_notifier_call(struct notifier_block *nb,
 158                                     unsigned long event, void *data)
 159 {
 160         struct device *dev = data;
 161
 162         switch (event) {
 163         case BUS_NOTIFY_BIND_DRIVER:
 164                 if (dev->of_node)
 165                         exynos_read_domain_from_dt(dev);
 166
 167                 break;
 168
 169         case BUS_NOTIFY_UNBOUND_DRIVER:
 170                 exynos_remove_device_from_domain(dev);
 171
 172                 break;
 173         }
 174         return NOTIFY_DONE;
 175 }
 176
 177 static struct notifier_block platform_nb = {
 178         .notifier_call = exynos_pm_notifier_call,
 179 };
 180
 181 static __init int exynos4_pm_init_power_domain(void)
 182 {
 183         struct platform_device *pdev;
 184         struct device_node *np;
 185
 186         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
 187                 struct exynos_pm_domain *pd;
 188                 int on, i;
 189                 struct device *dev;
 190
 191                 pdev = of_find_device_by_node(np);
 192                 dev = &pdev->dev;
 193
 194                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 195                 if (!pd) {
 196                         pr_err("%s: failed to allocate memory for domain\n",
 197                                         __func__);
 198                         return -ENOMEM;
 199                 }
 200
 201                 pd->pd.name = kstrdup(np->name, GFP_KERNEL);
 202                 pd->name = pd->pd.name;
 203                 pd->base = of_iomap(np, 0);
 204                 pd->pd.power_off = exynos_pd_power_off;
 205                 pd->pd.power_on = exynos_pd_power_on;
 206                 pd->pd.of_node = np;
 207
 208                 pd->oscclk = clk_get(dev, "oscclk");
 209                 if (IS_ERR(pd->oscclk))
 210                         goto no_clk;
 211
 212                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 213                         char clk_name[8];
 214
 215                         snprintf(clk_name, sizeof(clk_name), "clk%d", i);
 216                         pd->clk[i] = clk_get(dev, clk_name);
 217                         if (IS_ERR(pd->clk[i]))
 218                                 break;
 219                         snprintf(clk_name, sizeof(clk_name), "pclk%d", i);
 220                         pd->pclk[i] = clk_get(dev, clk_name);
 221                         if (IS_ERR(pd->pclk[i])) {
 222                                 clk_put(pd->clk[i]);
 223                                 pd->clk[i] = ERR_PTR(-EINVAL);
 224                                 break;
 225                         }
 226                 }
 227
 228                 if (IS_ERR(pd->clk[0]))
 229                         clk_put(pd->oscclk);
 230
 231 no_clk:
 232                 platform_set_drvdata(pdev, pd);
 233
 234                 on = __raw_readl(pd->base + 0x4) & S5P_INT_LOCAL_PWR_EN;
 235
 236                 pm_genpd_init(&pd->pd, NULL, !on);
 237         }
 238
 239         bus_register_notifier(&platform_bus_type, &platform_nb);
 240
 241         return 0;
 242 }
 243 arch_initcall(exynos4_pm_init_power_domain);