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 <asm/proc-fns.h> 20 21#include <mach/cpuidle.h> 22#include <mach/memory.h> 23 24#define DAVINCI_CPUIDLE_MAX_STATES 2 25 26struct davinci_ops { 27 void (*enter) (u32 flags); 28 void (*exit) (u32 flags); 29 u32 flags; 30}; 31 32/* fields in davinci_ops.flags */ 33#define DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN BIT(0) 34 35static struct cpuidle_driver davinci_idle_driver = { 36 .name = "cpuidle-davinci", 37 .owner = THIS_MODULE, 38}; 39 40static DEFINE_PER_CPU(struct cpuidle_device, davinci_cpuidle_device); 41static void __iomem *ddr2_reg_base; 42 43static void davinci_save_ddr_power(int enter, bool pdown) 44{ 45 u32 val; 46 47 val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET); 48 49 if (enter) { 50 if (pdown) 51 val |= DDR2_SRPD_BIT; 52 else 53 val &= ~DDR2_SRPD_BIT; 54 val |= DDR2_LPMODEN_BIT; 55 } else { 56 val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT); 57 } 58 59 __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET); 60} 61 62static void davinci_c2state_enter(u32 flags) 63{ 64 davinci_save_ddr_power(1, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); 65} 66 67static void davinci_c2state_exit(u32 flags) 68{ 69 davinci_save_ddr_power(0, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); 70} 71 72static struct davinci_ops davinci_states[DAVINCI_CPUIDLE_MAX_STATES] = { 73 [1] = { 74 .enter = davinci_c2state_enter, 75 .exit = davinci_c2state_exit, 76 }, 77}; 78 79/* Actual code that puts the SoC in different idle states */ 80static int davinci_enter_idle(struct cpuidle_device *dev, 81 struct cpuidle_state *state) 82{ 83 struct davinci_ops *ops = cpuidle_get_statedata(state); 84 struct timeval before, after; 85 int idle_time; 86 87 local_irq_disable(); 88 do_gettimeofday(&before); 89 90 if (ops && ops->enter) 91 ops->enter(ops->flags); 92 /* Wait for interrupt state */ 93 cpu_do_idle(); 94 if (ops && ops->exit) 95 ops->exit(ops->flags); 96 97 do_gettimeofday(&after); 98 local_irq_enable(); 99 idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC + 100 (after.tv_usec - before.tv_usec); 101 return idle_time; 102} 103 104static int __init davinci_cpuidle_probe(struct platform_device *pdev) 105{ 106 int ret; 107 struct cpuidle_device *device; 108 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data; 109 110 device = &per_cpu(davinci_cpuidle_device, smp_processor_id()); 111 112 if (!pdata) { 113 dev_err(&pdev->dev, "cannot get platform data\n"); 114 return -ENOENT; 115 } 116 117 ddr2_reg_base = pdata->ddr2_ctlr_base; 118 119 ret = cpuidle_register_driver(&davinci_idle_driver); 120 if (ret) { 121 dev_err(&pdev->dev, "failed to register driver\n"); 122 return ret; 123 } 124 125 /* Wait for interrupt state */ 126 device->states[0].enter = davinci_enter_idle; 127 device->states[0].exit_latency = 1; 128 device->states[0].target_residency = 10000; 129 device->states[0].flags = CPUIDLE_FLAG_TIME_VALID; 130 strcpy(device->states[0].name, "WFI"); 131 strcpy(device->states[0].desc, "Wait for interrupt"); 132 133 /* Wait for interrupt and DDR self refresh state */ 134 device->states[1].enter = davinci_enter_idle; 135 device->states[1].exit_latency = 10; 136 device->states[1].target_residency = 10000; 137 device->states[1].flags = CPUIDLE_FLAG_TIME_VALID; 138 strcpy(device->states[1].name, "DDR SR"); 139 strcpy(device->states[1].desc, "WFI and DDR Self Refresh"); 140 if (pdata->ddr2_pdown) 141 davinci_states[1].flags |= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN; 142 cpuidle_set_statedata(&device->states[1], &davinci_states[1]); 143 144 device->state_count = DAVINCI_CPUIDLE_MAX_STATES; 145 146 ret = cpuidle_register_device(device); 147 if (ret) { 148 dev_err(&pdev->dev, "failed to register device\n"); 149 cpuidle_unregister_driver(&davinci_idle_driver); 150 return ret; 151 } 152 153 return 0; 154} 155 156static struct platform_driver davinci_cpuidle_driver = { 157 .driver = { 158 .name = "cpuidle-davinci", 159 .owner = THIS_MODULE, 160 }, 161}; 162 163static int __init davinci_cpuidle_init(void) 164{ 165 return platform_driver_probe(&davinci_cpuidle_driver, 166 davinci_cpuidle_probe); 167} 168device_initcall(davinci_cpuidle_init); 169