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/time.h>
  18
  19 #include <asm/proc-fns.h>
  20 #include <asm/smp_scu.h>
  21 #include <asm/suspend.h>
  22 #include <asm/unified.h>
  23 #include <mach/regs-pmu.h>
  24 #include <mach/pmu.h>
  25
  26 #include <plat/cpu.h>
  27
  28 #define REG_DIRECTGO_ADDR       (samsung_rev() == EXYNOS4210_REV_1_1 ? \
  29                         S5P_INFORM7 : (samsung_rev() == EXYNOS4210_REV_1_0 ? \
  30                         (S5P_VA_SYSRAM + 0x24) : S5P_INFORM0))
  31 #define REG_DIRECTGO_FLAG       (samsung_rev() == EXYNOS4210_REV_1_1 ? \
  32                         S5P_INFORM6 : (samsung_rev() == EXYNOS4210_REV_1_0 ? \
  33                         (S5P_VA_SYSRAM + 0x20) : S5P_INFORM1))
  34
  35 #define S5P_CHECK_AFTR          0xFCBA0D10
  36
  37 static int exynos4_enter_idle(struct cpuidle_device *dev,
  38                         struct cpuidle_driver *drv,
  39                               int index);
  40 static int exynos4_enter_lowpower(struct cpuidle_device *dev,
  41                                 struct cpuidle_driver *drv,
  42                                 int index);
  43
  44 static struct cpuidle_state exynos4_cpuidle_set[] __initdata = {
  45         [0] = {
  46                 .enter                  = exynos4_enter_idle,
  47                 .exit_latency           = 1,
  48                 .target_residency       = 100000,
  49                 .flags                  = CPUIDLE_FLAG_TIME_VALID,
  50                 .name                   = "C0",
  51                 .desc                   = "ARM clock gating(WFI)",
  52         },
  53         [1] = {
  54                 .enter                  = exynos4_enter_lowpower,
  55                 .exit_latency           = 300,
  56                 .target_residency       = 100000,
  57                 .flags                  = CPUIDLE_FLAG_TIME_VALID,
  58                 .name                   = "C1",
  59                 .desc                   = "ARM power down",
  60         },
  61 };
  62
  63 static DEFINE_PER_CPU(struct cpuidle_device, exynos4_cpuidle_device);
  64
  65 static struct cpuidle_driver exynos4_idle_driver = {
  66         .name           = "exynos4_idle",
  67         .owner          = THIS_MODULE,
  68 };
  69
  70 /* Ext-GIC nIRQ/nFIQ is the only wakeup source in AFTR */
  71 static void exynos4_set_wakeupmask(void)
  72 {
  73         __raw_writel(0x0000ff3e, S5P_WAKEUP_MASK);
  74 }
  75
  76 static unsigned int g_pwr_ctrl, g_diag_reg;
  77
  78 static void save_cpu_arch_register(void)
  79 {
  80         /*read power control register*/
  81         asm("mrc p15, 0, %0, c15, c0, 0" : "=r"(g_pwr_ctrl) : : "cc");
  82         /*read diagnostic register*/
  83         asm("mrc p15, 0, %0, c15, c0, 1" : "=r"(g_diag_reg) : : "cc");
  84         return;
  85 }
  86
  87 static void restore_cpu_arch_register(void)
  88 {
  89         /*write power control register*/
  90         asm("mcr p15, 0, %0, c15, c0, 0" : : "r"(g_pwr_ctrl) : "cc");
  91         /*write diagnostic register*/
  92         asm("mcr p15, 0, %0, c15, c0, 1" : : "r"(g_diag_reg) : "cc");
  93         return;
  94 }
  95
  96 static int idle_finisher(unsigned long flags)
  97 {
  98         cpu_do_idle();
  99         return 1;
 100 }
 101
 102 static int exynos4_enter_core0_aftr(struct cpuidle_device *dev,
 103                                 struct cpuidle_driver *drv,
 104                                 int index)
 105 {
 106         struct timeval before, after;
 107         int idle_time;
 108         unsigned long tmp;
 109
 110         local_irq_disable();
 111         do_gettimeofday(&before);
 112
 113         exynos4_set_wakeupmask();
 114
 115         /* Set value of power down register for aftr mode */
 116         exynos4_sys_powerdown_conf(SYS_AFTR);
 117
 118         __raw_writel(virt_to_phys(s3c_cpu_resume), REG_DIRECTGO_ADDR);
 119         __raw_writel(S5P_CHECK_AFTR, REG_DIRECTGO_FLAG);
 120
 121         save_cpu_arch_register();
 122
 123         /* Setting Central Sequence Register for power down mode */
 124         tmp = __raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
 125         tmp &= ~S5P_CENTRAL_LOWPWR_CFG;
 126         __raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
 127
 128         cpu_pm_enter();
 129         cpu_suspend(0, idle_finisher);
 130
 131 #ifdef CONFIG_SMP
 132         scu_enable(S5P_VA_SCU);
 133 #endif
 134         cpu_pm_exit();
 135
 136         restore_cpu_arch_register();
 137
 138         /*
 139          * If PMU failed while entering sleep mode, WFI will be
 140          * ignored by PMU and then exiting cpu_do_idle().
 141          * S5P_CENTRAL_LOWPWR_CFG bit will not be set automatically
 142          * in this situation.
 143          */
 144         tmp = __raw_readl(S5P_CENTRAL_SEQ_CONFIGURATION);
 145         if (!(tmp & S5P_CENTRAL_LOWPWR_CFG)) {
 146                 tmp |= S5P_CENTRAL_LOWPWR_CFG;
 147                 __raw_writel(tmp, S5P_CENTRAL_SEQ_CONFIGURATION);
 148         }
 149
 150         /* Clear wakeup state register */
 151         __raw_writel(0x0, S5P_WAKEUP_STAT);
 152
 153         do_gettimeofday(&after);
 154
 155         local_irq_enable();
 156         idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
 157                     (after.tv_usec - before.tv_usec);
 158
 159         dev->last_residency = idle_time;
 160         return index;
 161 }
 162
 163 static int exynos4_enter_idle(struct cpuidle_device *dev,
 164                                 struct cpuidle_driver *drv,
 165                                 int index)
 166 {
 167         struct timeval before, after;
 168         int idle_time;
 169
 170         local_irq_disable();
 171         do_gettimeofday(&before);
 172
 173         cpu_do_idle();
 174
 175         do_gettimeofday(&after);
 176         local_irq_enable();
 177         idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
 178                     (after.tv_usec - before.tv_usec);
 179
 180         dev->last_residency = idle_time;
 181         return index;
 182 }
 183
 184 static int exynos4_enter_lowpower(struct cpuidle_device *dev,
 185                                 struct cpuidle_driver *drv,
 186                                 int index)
 187 {
 188         int new_index = index;
 189
 190         /* This mode only can be entered when other core's are offline */
 191         if (num_online_cpus() > 1)
 192                 new_index = drv->safe_state_index;
 193
 194         if (new_index == 0)
 195                 return exynos4_enter_idle(dev, drv, new_index);
 196         else
 197                 return exynos4_enter_core0_aftr(dev, drv, new_index);
 198 }
 199
 200 static int __init exynos4_init_cpuidle(void)
 201 {
 202         int i, max_cpuidle_state, cpu_id;
 203         struct cpuidle_device *device;
 204         struct cpuidle_driver *drv = &exynos4_idle_driver;
 205
 206         /* Setup cpuidle driver */
 207         drv->state_count = (sizeof(exynos4_cpuidle_set) /
 208                                        sizeof(struct cpuidle_state));
 209         max_cpuidle_state = drv->state_count;
 210         for (i = 0; i < max_cpuidle_state; i++) {
 211                 memcpy(&drv->states[i], &exynos4_cpuidle_set[i],
 212                                 sizeof(struct cpuidle_state));
 213         }
 214         drv->safe_state_index = 0;
 215         cpuidle_register_driver(&exynos4_idle_driver);
 216
 217         for_each_cpu(cpu_id, cpu_online_mask) {
 218                 device = &per_cpu(exynos4_cpuidle_device, cpu_id);
 219                 device->cpu = cpu_id;
 220
 221                 if (cpu_id == 0)
 222                         device->state_count = (sizeof(exynos4_cpuidle_set) /
 223                                                sizeof(struct cpuidle_state));
 224                 else
 225                         device->state_count = 1;        /* Support IDLE only */
 226
 227                 if (cpuidle_register_device(device)) {
 228                         printk(KERN_ERR "CPUidle register device failed\n,");
 229                         return -EIO;
 230                 }
 231         }
 232
 233         return 0;
 234 }
 235 device_initcall(exynos4_init_cpuidle);