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 #define INT_LOCAL_PWR_EN        0x7
  27 #define MAX_CLK_PER_DOMAIN      4
  28
  29 /*
  30  * Exynos specific wrapper around the generic power domain
  31  */
  32 struct exynos_pm_domain {
  33         void __iomem *base;
  34         char const *name;
  35         bool is_off;
  36         struct generic_pm_domain pd;
  37         struct clk *oscclk;
  38         struct clk *clk[MAX_CLK_PER_DOMAIN];
  39         struct clk *pclk[MAX_CLK_PER_DOMAIN];
  40 };
  41
  42 static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
  43 {
  44         struct exynos_pm_domain *pd;
  45         void __iomem *base;
  46         u32 timeout, pwr;
  47         char *op;
  48
  49         pd = container_of(domain, struct exynos_pm_domain, pd);
  50         base = pd->base;
  51
  52         /* Set oscclk before powering off a domain*/
  53         if (!power_on) {
  54                 int i;
  55
  56                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  57                         if (IS_ERR(pd->clk[i]))
  58                                 break;
  59                         if (clk_set_parent(pd->clk[i], pd->oscclk))
  60                                 pr_err("%s: error setting oscclk as parent to clock %d\n",
  61                                                 pd->name, i);
  62                 }
  63         }
  64
  65         pwr = power_on ? INT_LOCAL_PWR_EN : 0;
  66         __raw_writel(pwr, base);
  67
  68         /* Wait max 1ms */
  69         timeout = 10;
  70
  71         while ((__raw_readl(base + 0x4) & INT_LOCAL_PWR_EN) != pwr) {
  72                 if (!timeout) {
  73                         op = (power_on) ? "enable" : "disable";
  74                         pr_err("Power domain %s %s failed\n", domain->name, op);
  75                         return -ETIMEDOUT;
  76                 }
  77                 timeout--;
  78                 cpu_relax();
  79                 usleep_range(80, 100);
  80         }
  81
  82         /* Restore clocks after powering on a domain*/
  83         if (power_on) {
  84                 int i;
  85
  86                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  87                         if (IS_ERR(pd->clk[i]))
  88                                 break;
  89                         if (clk_set_parent(pd->clk[i], pd->pclk[i]))
  90                                 pr_err("%s: error setting parent to clock%d\n",
  91                                                 pd->name, i);
  92                 }
  93         }
  94
  95         return 0;
  96 }
  97
  98 static int exynos_pd_power_on(struct generic_pm_domain *domain)
  99 {
 100         return exynos_pd_power(domain, true);
 101 }
 102
 103 static int exynos_pd_power_off(struct generic_pm_domain *domain)
 104 {
 105         return exynos_pd_power(domain, false);
 106 }
 107
 108 static void exynos_add_device_to_domain(struct exynos_pm_domain *pd,
 109                                          struct device *dev)
 110 {
 111         int ret;
 112
 113         dev_dbg(dev, "adding to power domain %s\n", pd->pd.name);
 114
 115         while (1) {
 116                 ret = pm_genpd_add_device(&pd->pd, dev);
 117                 if (ret != -EAGAIN)
 118                         break;
 119                 cond_resched();
 120         }
 121
 122         pm_genpd_dev_need_restore(dev, true);
 123 }
 124
 125 static void exynos_remove_device_from_domain(struct device *dev)
 126 {
 127         struct generic_pm_domain *genpd = dev_to_genpd(dev);
 128         int ret;
 129
 130         dev_dbg(dev, "removing from power domain %s\n", genpd->name);
 131
 132         while (1) {
 133                 ret = pm_genpd_remove_device(genpd, dev);
 134                 if (ret != -EAGAIN)
 135                         break;
 136                 cond_resched();
 137         }
 138 }
 139
 140 static void exynos_read_domain_from_dt(struct device *dev)
 141 {
 142         struct platform_device *pd_pdev;
 143         struct exynos_pm_domain *pd;
 144         struct device_node *node;
 145
 146         node = of_parse_phandle(dev->of_node, "samsung,power-domain", 0);
 147         if (!node)
 148                 return;
 149         pd_pdev = of_find_device_by_node(node);
 150         if (!pd_pdev)
 151                 return;
 152         pd = platform_get_drvdata(pd_pdev);
 153         exynos_add_device_to_domain(pd, dev);
 154 }
 155
 156 static int exynos_pm_notifier_call(struct notifier_block *nb,
 157                                     unsigned long event, void *data)
 158 {
 159         struct device *dev = data;
 160
 161         switch (event) {
 162         case BUS_NOTIFY_BIND_DRIVER:
 163                 if (dev->of_node)
 164                         exynos_read_domain_from_dt(dev);
 165
 166                 break;
 167
 168         case BUS_NOTIFY_UNBOUND_DRIVER:
 169                 exynos_remove_device_from_domain(dev);
 170
 171                 break;
 172         }
 173         return NOTIFY_DONE;
 174 }
 175
 176 static struct notifier_block platform_nb = {
 177         .notifier_call = exynos_pm_notifier_call,
 178 };
 179
 180 static __init int exynos4_pm_init_power_domain(void)
 181 {
 182         struct platform_device *pdev;
 183         struct device_node *np;
 184
 185         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
 186                 struct exynos_pm_domain *pd;
 187                 int on, i;
 188                 struct device *dev;
 189
 190                 pdev = of_find_device_by_node(np);
 191                 dev = &pdev->dev;
 192
 193                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 194                 if (!pd) {
 195                         pr_err("%s: failed to allocate memory for domain\n",
 196                                         __func__);
 197                         return -ENOMEM;
 198                 }
 199
 200                 pd->pd.name = kstrdup(np->name, GFP_KERNEL);
 201                 pd->name = pd->pd.name;
 202                 pd->base = of_iomap(np, 0);
 203                 pd->pd.power_off = exynos_pd_power_off;
 204                 pd->pd.power_on = exynos_pd_power_on;
 205                 pd->pd.of_node = np;
 206
 207                 pd->oscclk = clk_get(dev, "oscclk");
 208                 if (IS_ERR(pd->oscclk))
 209                         goto no_clk;
 210
 211                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 212                         char clk_name[8];
 213
 214                         snprintf(clk_name, sizeof(clk_name), "clk%d", i);
 215                         pd->clk[i] = clk_get(dev, clk_name);
 216                         if (IS_ERR(pd->clk[i]))
 217                                 break;
 218                         snprintf(clk_name, sizeof(clk_name), "pclk%d", i);
 219                         pd->pclk[i] = clk_get(dev, clk_name);
 220                         if (IS_ERR(pd->pclk[i])) {
 221                                 clk_put(pd->clk[i]);
 222                                 pd->clk[i] = ERR_PTR(-EINVAL);
 223                                 break;
 224                         }
 225                 }
 226
 227                 if (IS_ERR(pd->clk[0]))
 228                         clk_put(pd->oscclk);
 229
 230 no_clk:
 231                 platform_set_drvdata(pdev, pd);
 232
 233                 on = __raw_readl(pd->base + 0x4) & INT_LOCAL_PWR_EN;
 234
 235                 pm_genpd_init(&pd->pd, NULL, !on);
 236         }
 237
 238         bus_register_notifier(&platform_bus_type, &platform_nb);
 239
 240         return 0;
 241 }
 242 arch_initcall(exynos4_pm_init_power_domain);