1 /* 2 * Copyright (C) 2014 Freescale Semiconductor, Inc. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #include <linux/cpuidle.h> 10 #include <linux/cpu_pm.h> 11 #include <linux/module.h> 12 #include <asm/cacheflush.h> 13 #include <asm/cpuidle.h> 14 #include <asm/suspend.h> 15 16 #include "common.h" 17 #include "cpuidle.h" 18 19 static int imx6sx_idle_finish(unsigned long val) 20 { 21 /* 22 * for Cortex-A7 which has an internal L2 23 * cache, need to flush it before powering 24 * down ARM platform, since flushing L1 cache 25 * here again has very small overhead, compared 26 * to adding conditional code for L2 cache type, 27 * just call flush_cache_all() is fine. 28 */ 29 flush_cache_all(); 30 cpu_do_idle(); 31 32 return 0; 33 } 34 35 static int imx6sx_enter_wait(struct cpuidle_device *dev, 36 struct cpuidle_driver *drv, int index) 37 { 38 imx6_set_lpm(WAIT_UNCLOCKED); 39 40 switch (index) { 41 case 1: 42 cpu_do_idle(); 43 break; 44 case 2: 45 imx6_enable_rbc(true); 46 imx_gpc_set_arm_power_in_lpm(true); 47 imx_set_cpu_jump(0, v7_cpu_resume); 48 /* Need to notify there is a cpu pm operation. */ 49 cpu_pm_enter(); 50 cpu_cluster_pm_enter(); 51 52 cpu_suspend(0, imx6sx_idle_finish); 53 54 cpu_cluster_pm_exit(); 55 cpu_pm_exit(); 56 imx_gpc_set_arm_power_in_lpm(false); 57 imx6_enable_rbc(false); 58 break; 59 default: 60 break; 61 } 62 63 imx6_set_lpm(WAIT_CLOCKED); 64 65 return index; 66 } 67 68 static struct cpuidle_driver imx6sx_cpuidle_driver = { 69 .name = "imx6sx_cpuidle", 70 .owner = THIS_MODULE, 71 .states = { 72 /* WFI */ 73 ARM_CPUIDLE_WFI_STATE, 74 /* WAIT */ 75 { 76 .exit_latency = 50, 77 .target_residency = 75, 78 .flags = CPUIDLE_FLAG_TIMER_STOP, 79 .enter = imx6sx_enter_wait, 80 .name = "WAIT", 81 .desc = "Clock off", 82 }, 83 /* WAIT + ARM power off */ 84 { 85 /* 86 * ARM gating 31us * 5 + RBC clear 65us 87 * and some margin for SW execution, here set it 88 * to 300us. 89 */ 90 .exit_latency = 300, 91 .target_residency = 500, 92 .flags = CPUIDLE_FLAG_TIMER_STOP, 93 .enter = imx6sx_enter_wait, 94 .name = "LOW-POWER-IDLE", 95 .desc = "ARM power off", 96 }, 97 }, 98 .state_count = 3, 99 .safe_state_index = 0, 100 }; 101 102 int __init imx6sx_cpuidle_init(void) 103 { 104 imx6_set_int_mem_clk_lpm(true); 105 imx6_enable_rbc(false); 106 imx_gpc_set_l2_mem_power_in_lpm(false); 107 /* 108 * set ARM power up/down timing to the fastest, 109 * sw2iso and sw can be set to one 32K cycle = 31us 110 * except for power up sw2iso which need to be 111 * larger than LDO ramp up time. 112 */ 113 imx_gpc_set_arm_power_up_timing(0xf, 1); 114 imx_gpc_set_arm_power_down_timing(1, 1); 115 116 return cpuidle_register(&imx6sx_cpuidle_driver, NULL); 117 } 118