kernel/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         struct clk *asb_clk[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         int i;
  50
  51         pd = container_of(domain, struct exynos_pm_domain, pd);
  52         base = pd->base;
  53
  54         for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  55                 if (IS_ERR(pd->asb_clk[i]))
  56                         break;
  57                 clk_prepare_enable(pd->asb_clk[i]);
  58         }
  59
  60         /* Set oscclk before powering off a domain*/
  61         if (!power_on) {
  62                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  63                         if (IS_ERR(pd->clk[i]))
  64                                 break;
  65                         if (clk_set_parent(pd->clk[i], pd->oscclk))
  66                                 pr_err("%s: error setting oscclk as parent to clock %d\n",
  67                                                 pd->name, i);
  68                 }
  69         }
  70
  71         pwr = power_on ? INT_LOCAL_PWR_EN : 0;
  72         __raw_writel(pwr, base);
  73
  74         /* Wait max 1ms */
  75         timeout = 10;
  76
  77         while ((__raw_readl(base + 0x4) & INT_LOCAL_PWR_EN) != pwr) {
  78                 if (!timeout) {
  79                         op = (power_on) ? "enable" : "disable";
  80                         pr_err("Power domain %s %s failed\n", domain->name, op);
  81                         return -ETIMEDOUT;
  82                 }
  83                 timeout--;
  84                 cpu_relax();
  85                 usleep_range(80, 100);
  86         }
  87
  88         /* Restore clocks after powering on a domain*/
  89         if (power_on) {
  90                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  91                         if (IS_ERR(pd->clk[i]))
  92                                 break;
  93                         if (clk_set_parent(pd->clk[i], pd->pclk[i]))
  94                                 pr_err("%s: error setting parent to clock%d\n",
  95                                                 pd->name, i);
  96                 }
  97         }
  98
  99         for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 100                 if (IS_ERR(pd->asb_clk[i]))
 101                         break;
 102                 clk_disable_unprepare(pd->asb_clk[i]);
 103         }
 104
 105         return 0;
 106 }
 107
 108 static int exynos_pd_power_on(struct generic_pm_domain *domain)
 109 {
 110         return exynos_pd_power(domain, true);
 111 }
 112
 113 static int exynos_pd_power_off(struct generic_pm_domain *domain)
 114 {
 115         return exynos_pd_power(domain, false);
 116 }
 117
 118 static __init int exynos4_pm_init_power_domain(void)
 119 {
 120         struct platform_device *pdev;
 121         struct device_node *np;
 122
 123         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
 124                 struct exynos_pm_domain *pd;
 125                 int on, i;
 126                 struct device *dev;
 127
 128                 pdev = of_find_device_by_node(np);
 129                 dev = &pdev->dev;
 130
 131                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 132                 if (!pd) {
 133                         pr_err("%s: failed to allocate memory for domain\n",
 134                                         __func__);
 135                         return -ENOMEM;
 136                 }
 137
 138                 pd->pd.name = kstrdup(dev_name(dev), GFP_KERNEL);
 139                 pd->name = pd->pd.name;
 140                 pd->base = of_iomap(np, 0);
 141                 pd->pd.power_off = exynos_pd_power_off;
 142                 pd->pd.power_on = exynos_pd_power_on;
 143
 144                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 145                         char clk_name[8];
 146
 147                         snprintf(clk_name, sizeof(clk_name), "asb%d", i);
 148                         pd->asb_clk[i] = clk_get(dev, clk_name);
 149                         if (IS_ERR(pd->asb_clk[i]))
 150                                 break;
 151                 }
 152
 153                 pd->oscclk = clk_get(dev, "oscclk");
 154                 if (IS_ERR(pd->oscclk))
 155                         goto no_clk;
 156
 157                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 158                         char clk_name[8];
 159
 160                         snprintf(clk_name, sizeof(clk_name), "clk%d", i);
 161                         pd->clk[i] = clk_get(dev, clk_name);
 162                         if (IS_ERR(pd->clk[i]))
 163                                 break;
 164                         snprintf(clk_name, sizeof(clk_name), "pclk%d", i);
 165                         pd->pclk[i] = clk_get(dev, clk_name);
 166                         if (IS_ERR(pd->pclk[i])) {
 167                                 clk_put(pd->clk[i]);
 168                                 pd->clk[i] = ERR_PTR(-EINVAL);
 169                                 break;
 170                         }
 171                 }
 172
 173                 if (IS_ERR(pd->clk[0]))
 174                         clk_put(pd->oscclk);
 175
 176 no_clk:
 177                 on = __raw_readl(pd->base + 0x4) & INT_LOCAL_PWR_EN;
 178
 179                 pm_genpd_init(&pd->pd, NULL, !on);
 180                 of_genpd_add_provider_simple(np, &pd->pd);
 181         }
 182
 183         /* Assign the child power domains to their parents */
 184         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
 185                 struct generic_pm_domain *child_domain, *parent_domain;
 186                 struct of_phandle_args args;
 187
 188                 args.np = np;
 189                 args.args_count = 0;
 190                 child_domain = of_genpd_get_from_provider(&args);
 191                 if (IS_ERR(child_domain))
 192                         continue;
 193
 194                 if (of_parse_phandle_with_args(np, "power-domains",
 195                                          "#power-domain-cells", 0, &args) != 0)
 196                         continue;
 197
 198                 parent_domain = of_genpd_get_from_provider(&args);
 199                 if (IS_ERR(parent_domain))
 200                         continue;
 201
 202                 if (pm_genpd_add_subdomain(parent_domain, child_domain))
 203                         pr_warn("%s failed to add subdomain: %s\n",
 204                                 parent_domain->name, child_domain->name);
 205                 else
 206                         pr_info("%s has as child subdomain: %s.\n",
 207                                 parent_domain->name, child_domain->name);
 208                 of_node_put(np);
 209         }
 210
 211         return 0;
 212 }
 213 arch_initcall(exynos4_pm_init_power_domain);