drivers/soc/samsung/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 MAX_CLK_PER_DOMAIN      4
  27
  28 struct exynos_pm_domain_config {
  29         /* Value for LOCAL_PWR_CFG and STATUS fields for each domain */
  30         u32 local_pwr_cfg;
  31 };
  32
  33 /*
  34  * Exynos specific wrapper around the generic power domain
  35  */
  36 struct exynos_pm_domain {
  37         void __iomem *base;
  38         char const *name;
  39         bool is_off;
  40         struct generic_pm_domain pd;
  41         struct clk *oscclk;
  42         struct clk *clk[MAX_CLK_PER_DOMAIN];
  43         struct clk *pclk[MAX_CLK_PER_DOMAIN];
  44         struct clk *asb_clk[MAX_CLK_PER_DOMAIN];
  45         u32 local_pwr_cfg;
  46 };
  47
  48 static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on)
  49 {
  50         struct exynos_pm_domain *pd;
  51         void __iomem *base;
  52         u32 timeout, pwr;
  53         char *op;
  54         int i;
  55
  56         pd = container_of(domain, struct exynos_pm_domain, pd);
  57         base = pd->base;
  58
  59         for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  60                 if (IS_ERR(pd->asb_clk[i]))
  61                         break;
  62                 clk_prepare_enable(pd->asb_clk[i]);
  63         }
  64
  65         /* Set oscclk before powering off a domain*/
  66         if (!power_on) {
  67                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  68                         if (IS_ERR(pd->clk[i]))
  69                                 break;
  70                         pd->pclk[i] = clk_get_parent(pd->clk[i]);
  71                         if (clk_set_parent(pd->clk[i], pd->oscclk))
  72                                 pr_err("%s: error setting oscclk as parent to clock %d\n",
  73                                                 pd->name, i);
  74                 }
  75         }
  76
  77         pwr = power_on ? pd->local_pwr_cfg : 0;
  78         writel_relaxed(pwr, base);
  79
  80         /* Wait max 1ms */
  81         timeout = 10;
  82
  83         while ((readl_relaxed(base + 0x4) & pd->local_pwr_cfg) != pwr) {
  84                 if (!timeout) {
  85                         op = (power_on) ? "enable" : "disable";
  86                         pr_err("Power domain %s %s failed\n", domain->name, op);
  87                         return -ETIMEDOUT;
  88                 }
  89                 timeout--;
  90                 cpu_relax();
  91                 usleep_range(80, 100);
  92         }
  93
  94         /* Restore clocks after powering on a domain*/
  95         if (power_on) {
  96                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
  97                         if (IS_ERR(pd->clk[i]))
  98                                 break;
  99
 100                         if (IS_ERR(pd->pclk[i]))
 101                                 continue; /* Skip on first power up */
 102                         if (clk_set_parent(pd->clk[i], pd->pclk[i]))
 103                                 pr_err("%s: error setting parent to clock%d\n",
 104                                                 pd->name, i);
 105                 }
 106         }
 107
 108         for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 109                 if (IS_ERR(pd->asb_clk[i]))
 110                         break;
 111                 clk_disable_unprepare(pd->asb_clk[i]);
 112         }
 113
 114         return 0;
 115 }
 116
 117 static int exynos_pd_power_on(struct generic_pm_domain *domain)
 118 {
 119         return exynos_pd_power(domain, true);
 120 }
 121
 122 static int exynos_pd_power_off(struct generic_pm_domain *domain)
 123 {
 124         return exynos_pd_power(domain, false);
 125 }
 126
 127 static const struct exynos_pm_domain_config exynos4210_cfg __initconst = {
 128         .local_pwr_cfg          = 0x7,
 129 };
 130
 131 static const struct of_device_id exynos_pm_domain_of_match[] __initconst = {
 132         {
 133                 .compatible = "samsung,exynos4210-pd",
 134                 .data = &exynos4210_cfg,
 135         },
 136         { },
 137 };
 138
 139 static __init int exynos4_pm_init_power_domain(void)
 140 {
 141         struct device_node *np;
 142         const struct of_device_id *match;
 143
 144         for_each_matching_node_and_match(np, exynos_pm_domain_of_match, &match) {
 145                 const struct exynos_pm_domain_config *pm_domain_cfg;
 146                 struct exynos_pm_domain *pd;
 147                 int on, i;
 148
 149                 pm_domain_cfg = match->data;
 150
 151                 pd = kzalloc(sizeof(*pd), GFP_KERNEL);
 152                 if (!pd) {
 153                         pr_err("%s: failed to allocate memory for domain\n",
 154                                         __func__);
 155                         of_node_put(np);
 156                         return -ENOMEM;
 157                 }
 158                 pd->pd.name = kstrdup_const(strrchr(np->full_name, '/') + 1,
 159                                             GFP_KERNEL);
 160                 if (!pd->pd.name) {
 161                         kfree(pd);
 162                         of_node_put(np);
 163                         return -ENOMEM;
 164                 }
 165
 166                 pd->name = pd->pd.name;
 167                 pd->base = of_iomap(np, 0);
 168                 if (!pd->base) {
 169                         pr_warn("%s: failed to map memory\n", __func__);
 170                         kfree_const(pd->pd.name);
 171                         kfree(pd);
 172                         continue;
 173                 }
 174
 175                 pd->pd.power_off = exynos_pd_power_off;
 176                 pd->pd.power_on = exynos_pd_power_on;
 177                 pd->local_pwr_cfg = pm_domain_cfg->local_pwr_cfg;
 178
 179                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 180                         char clk_name[8];
 181
 182                         snprintf(clk_name, sizeof(clk_name), "asb%d", i);
 183                         pd->asb_clk[i] = of_clk_get_by_name(np, clk_name);
 184                         if (IS_ERR(pd->asb_clk[i]))
 185                                 break;
 186                 }
 187
 188                 pd->oscclk = of_clk_get_by_name(np, "oscclk");
 189                 if (IS_ERR(pd->oscclk))
 190                         goto no_clk;
 191
 192                 for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) {
 193                         char clk_name[8];
 194
 195                         snprintf(clk_name, sizeof(clk_name), "clk%d", i);
 196                         pd->clk[i] = of_clk_get_by_name(np, clk_name);
 197                         if (IS_ERR(pd->clk[i]))
 198                                 break;
 199                         /*
 200                          * Skip setting parent on first power up.
 201                          * The parent at this time may not be useful at all.
 202                          */
 203                         pd->pclk[i] = ERR_PTR(-EINVAL);
 204                 }
 205
 206                 if (IS_ERR(pd->clk[0]))
 207                         clk_put(pd->oscclk);
 208
 209 no_clk:
 210                 on = readl_relaxed(pd->base + 0x4) & pd->local_pwr_cfg;
 211
 212                 pm_genpd_init(&pd->pd, NULL, !on);
 213                 of_genpd_add_provider_simple(np, &pd->pd);
 214         }
 215
 216         /* Assign the child power domains to their parents */
 217         for_each_matching_node(np, exynos_pm_domain_of_match) {
 218                 struct of_phandle_args child, parent;
 219
 220                 child.np = np;
 221                 child.args_count = 0;
 222
 223                 if (of_parse_phandle_with_args(np, "power-domains",
 224                                                "#power-domain-cells", 0,
 225                                                &parent) != 0)
 226                         continue;
 227
 228                 if (of_genpd_add_subdomain(&parent, &child))
 229                         pr_warn("%s failed to add subdomain: %s\n",
 230                                 parent.np->name, child.np->name);
 231                 else
 232                         pr_info("%s has as child subdomain: %s.\n",
 233                                 parent.np->name, child.np->name);
 234         }
 235
 236         return 0;
 237 }
 238 core_initcall(exynos4_pm_init_power_domain);