arch/arm/mach-exynos/cpuidle.c

   1 /* linux/arch/arm/mach-exynos4/cpuidle.c
   2  *
   3  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
   4  *              http://www.samsung.com
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9 */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/cpuidle.h>
  14 #include <linux/cpu_pm.h>
  15 #include <linux/io.h>
  16 #include <linux/export.h>
  17 #include <linux/module.h>
  18 #include <linux/time.h>
  19 #include <linux/platform_device.h>
  20
  21 #include <asm/proc-fns.h>
  22 #include <asm/smp_scu.h>
  23 #include <asm/suspend.h>
  24 #include <asm/unified.h>
  25 #include <asm/cpuidle.h>
  26
  27 #include <plat/cpu.h>
  28 #include <plat/pm.h>
  29
  30 #include <mach/map.h>
  31
  32 #include "common.h"
  33 #include "regs-pmu.h"
  34
  35 #define REG_DIRECTGO_ADDR       (samsung_rev() == EXYNOS4210_REV_1_1 ? \
  36                         S5P_INFORM7 : (samsung_rev() == EXYNOS4210_REV_1_0 ? \
  37                         (S5P_VA_SYSRAM + 0x24) : S5P_INFORM0))
  38 #define REG_DIRECTGO_FLAG       (samsung_rev() == EXYNOS4210_REV_1_1 ? \
  39                         S5P_INFORM6 : (samsung_rev() == EXYNOS4210_REV_1_0 ? \
  40                         (S5P_VA_SYSRAM + 0x20) : S5P_INFORM1))
  41
  42 #define S5P_CHECK_AFTR          0xFCBA0D10
  43
  44 /* Ext-GIC nIRQ/nFIQ is the only wakeup source in AFTR */
  45 static void exynos4_set_wakeupmask(void)
  46 {
  47         __raw_writel(0x0000ff3e, S5P_WAKEUP_MASK);
  48 }
  49
  50 static unsigned int g_pwr_ctrl, g_diag_reg;
  51
  52 static void save_cpu_arch_register(void)
  53 {
  54         /*read power control register*/
  55         asm("mrc p15, 0, %0, c15, c0, 0" : "=r"(g_pwr_ctrl) : : "cc");
  56         /*read diagnostic register*/
  57         asm("mrc p15, 0, %0, c15, c0, 1" : "=r"(g_diag_reg) : : "cc");
  58         return;
  59 }
  60
  61 static void restore_cpu_arch_register(void)
  62 {
  63         /*write power control register*/
  64         asm("mcr p15, 0, %0, c15, c0, 0" : : "r"(g_pwr_ctrl) : "cc");
  65         /*write diagnostic register*/
  66         asm("mcr p15, 0, %0, c15, c0, 1" : : "r"(g_diag_reg) : "cc");
  67         return;
  68 }
  69
  70 static int idle_finisher(unsigned long flags)
  71 {
  72         cpu_do_idle();
  73         return 1;
  74 }
  75
  76 static int exynos4_enter_core0_aftr(struct cpuidle_device *dev,
  77                                 struct cpuidle_driver *drv,
  78                                 int index)
  79 {
  80         unsigned long tmp;
  81
  82         exynos4_set_wakeupmask();
  83
  84         /* Set value of power down register for aftr mode */
  85         exynos_sys_powerdown_conf(SYS_AFTR);
  86
  87         __raw_writel(virt_to_phys(exynos_cpu_resume), REG_DIRECTGO_ADDR);
  88         __raw_writel(S5P_CHECK_AFTR, REG_DIRECTGO_FLAG);
  89
  90         save_cpu_arch_register();
  91
  92         /* Setting Central Sequence Register for power down mode */
  93         tmp = __raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
  94         tmp &= ~S5P_CENTRAL_LOWPWR_CFG;
  95         __raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
  96
  97         cpu_pm_enter();
  98         cpu_suspend(0, idle_finisher);
  99
 100 #ifdef CONFIG_SMP
 101         if (!soc_is_exynos5250())
 102                 scu_enable(S5P_VA_SCU);
 103 #endif
 104         cpu_pm_exit();
 105
 106         restore_cpu_arch_register();
 107
 108         /*
 109          * If PMU failed while entering sleep mode, WFI will be
 110          * ignored by PMU and then exiting cpu_do_idle().
 111          * S5P_CENTRAL_LOWPWR_CFG bit will not be set automatically
 112          * in this situation.
 113          */
 114         tmp = __raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
 115         if (!(tmp & S5P_CENTRAL_LOWPWR_CFG)) {
 116                 tmp |= S5P_CENTRAL_LOWPWR_CFG;
 117                 __raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
 118         }
 119
 120         /* Clear wakeup state register */
 121         __raw_writel(0x0, S5P_WAKEUP_STAT);
 122
 123         return index;
 124 }
 125
 126 static int exynos4_enter_lowpower(struct cpuidle_device *dev,
 127                                 struct cpuidle_driver *drv,
 128                                 int index)
 129 {
 130         int new_index = index;
 131
 132         /* AFTR can only be entered when cores other than CPU0 are offline */
 133         if (num_online_cpus() > 1 || dev->cpu != 0)
 134                 new_index = drv->safe_state_index;
 135
 136         if (new_index == 0)
 137                 return arm_cpuidle_simple_enter(dev, drv, new_index);
 138         else
 139                 return exynos4_enter_core0_aftr(dev, drv, new_index);
 140 }
 141
 142 static struct cpuidle_driver exynos4_idle_driver = {
 143         .name                   = "exynos4_idle",
 144         .owner                  = THIS_MODULE,
 145         .states = {
 146                 [0] = ARM_CPUIDLE_WFI_STATE,
 147                 [1] = {
 148                         .enter                  = exynos4_enter_lowpower,
 149                         .exit_latency           = 300,
 150                         .target_residency       = 100000,
 151                         .flags                  = CPUIDLE_FLAG_TIME_VALID,
 152                         .name                   = "C1",
 153                         .desc                   = "ARM power down",
 154                 },
 155         },
 156         .state_count = 2,
 157         .safe_state_index = 0,
 158 };
 159
 160 static int exynos_cpuidle_probe(struct platform_device *pdev)
 161 {
 162         int ret;
 163
 164         if (soc_is_exynos5440())
 165                 exynos4_idle_driver.state_count = 1;
 166
 167         ret = cpuidle_register(&exynos4_idle_driver, NULL);
 168         if (ret) {
 169                 dev_err(&pdev->dev, "failed to register cpuidle driver\n");
 170                 return ret;
 171         }
 172
 173         return 0;
 174 }
 175
 176 static struct platform_driver exynos_cpuidle_driver = {
 177         .probe  = exynos_cpuidle_probe,
 178         .driver = {
 179                 .name = "exynos_cpuidle",
 180                 .owner = THIS_MODULE,
 181         },
 182 };
 183
 184 module_platform_driver(exynos_cpuidle_driver);