1 /* 2 * Copyright (C) 2012 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/module.h> 11 #include <asm/cpuidle.h> 12 13 #include <soc/imx/cpuidle.h> 14 15 #include "common.h" 16 #include "cpuidle.h" 17 #include "hardware.h" 18 19 static int num_idle_cpus = 0; 20 static DEFINE_SPINLOCK(cpuidle_lock); 21 22 static int imx6q_enter_wait(struct cpuidle_device *dev, 23 struct cpuidle_driver *drv, int index) 24 { 25 spin_lock(&cpuidle_lock); 26 if (++num_idle_cpus == num_online_cpus()) 27 imx6_set_lpm(WAIT_UNCLOCKED); 28 spin_unlock(&cpuidle_lock); 29 30 cpu_do_idle(); 31 32 spin_lock(&cpuidle_lock); 33 if (num_idle_cpus-- == num_online_cpus()) 34 imx6_set_lpm(WAIT_CLOCKED); 35 spin_unlock(&cpuidle_lock); 36 37 return index; 38 } 39 40 static struct cpuidle_driver imx6q_cpuidle_driver = { 41 .name = "imx6q_cpuidle", 42 .owner = THIS_MODULE, 43 .states = { 44 /* WFI */ 45 ARM_CPUIDLE_WFI_STATE, 46 /* WAIT */ 47 { 48 .exit_latency = 50, 49 .target_residency = 75, 50 .flags = CPUIDLE_FLAG_TIMER_STOP, 51 .enter = imx6q_enter_wait, 52 .name = "WAIT", 53 .desc = "Clock off", 54 }, 55 }, 56 .state_count = 2, 57 .safe_state_index = 0, 58 }; 59 60 /* 61 * i.MX6 Q/DL has an erratum (ERR006687) that prevents the FEC from waking the 62 * CPUs when they are in wait(unclocked) state. As the hardware workaround isn't 63 * applicable to all boards, disable the deeper idle state when the workaround 64 * isn't present and the FEC is in use. 65 */ 66 void imx6q_cpuidle_fec_irqs_used(void) 67 { 68 imx6q_cpuidle_driver.states[1].disabled = true; 69 } 70 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_used); 71 72 void imx6q_cpuidle_fec_irqs_unused(void) 73 { 74 imx6q_cpuidle_driver.states[1].disabled = false; 75 } 76 EXPORT_SYMBOL_GPL(imx6q_cpuidle_fec_irqs_unused); 77 78 int __init imx6q_cpuidle_init(void) 79 { 80 /* Set INT_MEM_CLK_LPM bit to get a reliable WAIT mode support */ 81 imx6_set_int_mem_clk_lpm(true); 82 83 return cpuidle_register(&imx6q_cpuidle_driver, NULL); 84 } 85