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                         pd->pclk[i] = clk_get_parent(pd->clk[i]);
  66                         if (clk_set_parent(pd->clk[i], pd->oscclk))
  67                                 pr_err("%s: error setting oscclk as parent to clock %d\n",
  68                                                 pd->name, i);
  69                 }
  70         }
  71
  72         pwr = power_on ? INT_LOCAL_PWR_EN : 0;
  73         __raw_writel(pwr, base);
  74
  75         /* Wait max 1ms */
  76         timeout = 10;
  77
  78         while ((__raw_readl(base + 0x4) & INT_LOCAL_PWR_EN) != pwr) {
  79                 if (!timeout) {
  80                         op = (power_on) ? "enable" : "disable";
  81                         pr_err("Power domain %s %s failed\n", domain->name, op);
  82                         return -ETIMEDOUT;
  83                 }
  84                 timeout--;
  85                 cpu_relax();
  86                 usleep_range(80, 100);
  87         }
  88
  89         /* Restore clocks after powering on a domain*/
  90         if (power_on) {
  91                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  92                         if (IS_ERR(pd->clk[i]))
  93                                 break;
  94
  95                         if (IS_ERR(pd->clk[i]))
  96                                 continue; /* Skip on first power up */
  97                         if (clk_set_parent(pd->clk[i], pd->pclk[i]))
  98                                 pr_err("%s: error setting parent to clock%d\n",
  99                                                 pd->name, i);
 100                 }
 101         }
 102
 103         for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 104                 if (IS_ERR(pd->asb_clk[i]))
 105                         break;
 106                 clk_disable_unprepare(pd->asb_clk[i]);
 107         }
 108
 109         return 0;
 110 }
 111
 112 static int exynos_pd_power_on(struct generic_pm_domain *domain)
 113 {
 114         return exynos_pd_power(domain, true);
 115 }
 116
 117 static int exynos_pd_power_off(struct generic_pm_domain *domain)
 118 {
 119         return exynos_pd_power(domain, false);
 120 }
 121
 122 static __init int exynos4_pm_init_power_domain(void)
 123 {
 124         struct device_node *np;
 125
 126         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
 127                 struct exynos_pm_domain *pd;
 128                 int on, i;
 129
 130                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 131                 if (!pd) {
 132                         pr_err("%s: failed to allocate memory for domain\n",
 133                                         __func__);
 134                         of_node_put(np);
 135                         return -ENOMEM;
 136                 }
 137                 pd->pd.name = kstrdup_const(strrchr(np->full_name, '/') + 1,
 138                                             GFP_KERNEL);
 139                 if (!pd->pd.name) {
 140                         kfree(pd);
 141                         of_node_put(np);
 142                         return -ENOMEM;
 143                 }
 144
 145                 pd->name = pd->pd.name;
 146                 pd->base = of_iomap(np, 0);
 147                 if (!pd->base) {
 148                         pr_warn("%s: failed to map memory\n", __func__);
 149                         kfree_const(pd->pd.name);
 150                         kfree(pd);
 151                         continue;
 152                 }
 153
 154                 pd->pd.power_off = exynos_pd_power_off;
 155                 pd->pd.power_on = exynos_pd_power_on;
 156
 157                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 158                         char clk_name[8];
 159
 160                         snprintf(clk_name, sizeof(clk_name), "asb%d", i);
 161                         pd->asb_clk[i] = of_clk_get_by_name(np, clk_name);
 162                         if (IS_ERR(pd->asb_clk[i]))
 163                                 break;
 164                 }
 165
 166                 pd->oscclk = of_clk_get_by_name(np, "oscclk");
 167                 if (IS_ERR(pd->oscclk))
 168                         goto no_clk;
 169
 170                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 171                         char clk_name[8];
 172
 173                         snprintf(clk_name, sizeof(clk_name), "clk%d", i);
 174                         pd->clk[i] = of_clk_get_by_name(np, clk_name);
 175                         if (IS_ERR(pd->clk[i]))
 176                                 break;
 177                         /*
 178                          * Skip setting parent on first power up.
 179                          * The parent at this time may not be useful at all.
 180                          */
 181                         pd->pclk[i] = ERR_PTR(-EINVAL);
 182                 }
 183
 184                 if (IS_ERR(pd->clk[0]))
 185                         clk_put(pd->oscclk);
 186
 187 no_clk:
 188                 on = __raw_readl(pd->base + 0x4) & INT_LOCAL_PWR_EN;
 189
 190                 pm_genpd_init(&pd->pd, NULL, !on);
 191                 of_genpd_add_provider_simple(np, &pd->pd);
 192         }
 193
 194         /* Assign the child power domains to their parents */
 195         for_each_compatible_node(np, NULL, "samsung,exynos4210-pd") {
 196                 struct generic_pm_domain *child_domain, *parent_domain;
 197                 struct of_phandle_args args;
 198
 199                 args.np = np;
 200                 args.args_count = 0;
 201                 child_domain = of_genpd_get_from_provider(&args);
 202                 if (IS_ERR(child_domain))
 203                         continue;
 204
 205                 if (of_parse_phandle_with_args(np, "power-domains",
 206                                          "#power-domain-cells", 0, &args) != 0)
 207                         continue;
 208
 209                 parent_domain = of_genpd_get_from_provider(&args);
 210                 if (IS_ERR(parent_domain))
 211                         continue;
 212
 213                 if (pm_genpd_add_subdomain(parent_domain, child_domain))
 214                         pr_warn("%s failed to add subdomain: %s\n",
 215                                 parent_domain->name, child_domain->name);
 216                 else
 217                         pr_info("%s has as child subdomain: %s.\n",
 218                                 parent_domain->name, child_domain->name);
 219         }
 220
 221         return 0;
 222 }
 223 core_initcall(exynos4_pm_init_power_domain);