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 __init int exynos4_pm_init_power_domain(void)
 109 {
 110         struct platform_device *pdev;
 111         struct device_node *np;
 112
 113         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
 114                 struct exynos_pm_domain *pd;
 115                 int on, i;
 116                 struct device *dev;
 117
 118                 pdev = of_find_device_by_node(np);
 119                 dev = &pdev->dev;
 120
 121                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 122                 if (!pd) {
 123                         pr_err("%s: failed to allocate memory for domain\n",
 124                                         __func__);
 125                         return -ENOMEM;
 126                 }
 127
 128                 pd->pd.name = kstrdup(np->name, GFP_KERNEL);
 129                 pd->name = pd->pd.name;
 130                 pd->base = of_iomap(np, 0);
 131                 pd->pd.power_off = exynos_pd_power_off;
 132                 pd->pd.power_on = exynos_pd_power_on;
 133
 134                 pd->oscclk = clk_get(dev, "oscclk");
 135                 if (IS_ERR(pd->oscclk))
 136                         goto no_clk;
 137
 138                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 139                         char clk_name[8];
 140
 141                         snprintf(clk_name, sizeof(clk_name), "clk%d", i);
 142                         pd->clk[i] = clk_get(dev, clk_name);
 143                         if (IS_ERR(pd->clk[i]))
 144                                 break;
 145                         snprintf(clk_name, sizeof(clk_name), "pclk%d", i);
 146                         pd->pclk[i] = clk_get(dev, clk_name);
 147                         if (IS_ERR(pd->pclk[i])) {
 148                                 clk_put(pd->clk[i]);
 149                                 pd->clk[i] = ERR_PTR(-EINVAL);
 150                                 break;
 151                         }
 152                 }
 153
 154                 if (IS_ERR(pd->clk[0]))
 155                         clk_put(pd->oscclk);
 156
 157 no_clk:
 158                 on = __raw_readl(pd->base + 0x4) & INT_LOCAL_PWR_EN;
 159
 160                 pm_genpd_init(&pd->pd, NULL, !on);
 161                 of_genpd_add_provider_simple(np, &pd->pd);
 162         }
 163
 164         /* Assign the child power domains to their parents */
 165         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
 166                 struct generic_pm_domain *child_domain, *parent_domain;
 167                 struct of_phandle_args args;
 168
 169                 args.np = np;
 170                 args.args_count = 0;
 171                 child_domain = of_genpd_get_from_provider(&args);
 172                 if (!child_domain)
 173                         continue;
 174
 175                 if (of_parse_phandle_with_args(np, "power-domains",
 176                                          "#power-domain-cells", 0, &args) != 0)
 177                         continue;
 178
 179                 parent_domain = of_genpd_get_from_provider(&args);
 180                 if (!parent_domain)
 181                         continue;
 182
 183                 if (pm_genpd_add_subdomain(parent_domain, child_domain))
 184                         pr_warn("%s failed to add subdomain: %s\n",
 185                                 parent_domain->name, child_domain->name);
 186                 else
 187                         pr_info("%s has as child subdomain: %s.\n",
 188                                 parent_domain->name, child_domain->name);
 189                 of_node_put(np);
 190         }
 191
 192         return 0;
 193 }
 194 arch_initcall(exynos4_pm_init_power_domain);