1 /* 2 * CPU idle for DaVinci SoCs 3 * 4 * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/ 5 * 6 * Derived from Marvell Kirkwood CPU idle code 7 * (arch/arm/mach-kirkwood/cpuidle.c) 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/init.h> 16 #include <linux/platform_device.h> 17 #include <linux/cpuidle.h> 18 #include <linux/io.h> 19 #include <linux/export.h> 20 #include <asm/proc-fns.h> 21 #include <asm/cpuidle.h> 22 23 #include <mach/cpuidle.h> 24 #include <mach/ddr2.h> 25 26 #define DAVINCI_CPUIDLE_MAX_STATES 2 27 28 struct davinci_ops { 29 void (*enter) (u32 flags); 30 void (*exit) (u32 flags); 31 u32 flags; 32 }; 33 34 /* Actual code that puts the SoC in different idle states */ 35 static int davinci_enter_idle(struct cpuidle_device *dev, 36 struct cpuidle_driver *drv, 37 int index) 38 { 39 struct cpuidle_state_usage *state_usage = &dev->states_usage[index]; 40 struct davinci_ops *ops = cpuidle_get_statedata(state_usage); 41 42 if (ops && ops->enter) 43 ops->enter(ops->flags); 44 45 index = cpuidle_wrap_enter(dev, drv, index, 46 arm_cpuidle_simple_enter); 47 48 if (ops && ops->exit) 49 ops->exit(ops->flags); 50 51 return index; 52 } 53 54 /* fields in davinci_ops.flags */ 55 #define DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN BIT(0) 56 57 static struct cpuidle_driver davinci_idle_driver = { 58 .name = "cpuidle-davinci", 59 .owner = THIS_MODULE, 60 .en_core_tk_irqen = 1, 61 .states[0] = ARM_CPUIDLE_WFI_STATE, 62 .states[1] = { 63 .enter = davinci_enter_idle, 64 .exit_latency = 10, 65 .target_residency = 100000, 66 .flags = CPUIDLE_FLAG_TIME_VALID, 67 .name = "DDR SR", 68 .desc = "WFI and DDR Self Refresh", 69 }, 70 .state_count = DAVINCI_CPUIDLE_MAX_STATES, 71 }; 72 73 static DEFINE_PER_CPU(struct cpuidle_device, davinci_cpuidle_device); 74 static void __iomem *ddr2_reg_base; 75 76 static void davinci_save_ddr_power(int enter, bool pdown) 77 { 78 u32 val; 79 80 val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET); 81 82 if (enter) { 83 if (pdown) 84 val |= DDR2_SRPD_BIT; 85 else 86 val &= ~DDR2_SRPD_BIT; 87 val |= DDR2_LPMODEN_BIT; 88 } else { 89 val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT); 90 } 91 92 __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET); 93 } 94 95 static void davinci_c2state_enter(u32 flags) 96 { 97 davinci_save_ddr_power(1, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); 98 } 99 100 static void davinci_c2state_exit(u32 flags) 101 { 102 davinci_save_ddr_power(0, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); 103 } 104 105 static struct davinci_ops davinci_states[DAVINCI_CPUIDLE_MAX_STATES] = { 106 [1] = { 107 .enter = davinci_c2state_enter, 108 .exit = davinci_c2state_exit, 109 }, 110 }; 111 112 static int __init davinci_cpuidle_probe(struct platform_device *pdev) 113 { 114 int ret; 115 struct cpuidle_device *device; 116 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data; 117 118 device = &per_cpu(davinci_cpuidle_device, smp_processor_id()); 119 120 if (!pdata) { 121 dev_err(&pdev->dev, "cannot get platform data\n"); 122 return -ENOENT; 123 } 124 125 ddr2_reg_base = pdata->ddr2_ctlr_base; 126 127 if (pdata->ddr2_pdown) 128 davinci_states[1].flags |= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN; 129 cpuidle_set_statedata(&device->states_usage[1], &davinci_states[1]); 130 131 device->state_count = DAVINCI_CPUIDLE_MAX_STATES; 132 133 ret = cpuidle_register_driver(&davinci_idle_driver); 134 if (ret) { 135 dev_err(&pdev->dev, "failed to register driver\n"); 136 return ret; 137 } 138 139 ret = cpuidle_register_device(device); 140 if (ret) { 141 dev_err(&pdev->dev, "failed to register device\n"); 142 cpuidle_unregister_driver(&davinci_idle_driver); 143 return ret; 144 } 145 146 return 0; 147 } 148 149 static struct platform_driver davinci_cpuidle_driver = { 150 .driver = { 151 .name = "cpuidle-davinci", 152 .owner = THIS_MODULE, 153 }, 154 }; 155 156 static int __init davinci_cpuidle_init(void) 157 { 158 return platform_driver_probe(&davinci_cpuidle_driver, 159 davinci_cpuidle_probe); 160 } 161 device_initcall(davinci_cpuidle_init); 162 163