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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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49a1a99c53
When the CPU is in ARM power off state the ARM architected timers are stopped. The flag is already present in the higher power WAIT mode. This allows to use the ARM generic timer on i.MX 6UL/6ULL SoC. Without the flag the kernel freezes when the timer enters the first time ARM power off mode. Note: The default timer on i.MX6SX is the i.MX GPT timer which is not disabled during CPU idle. However, the timer is not affected by the CPUIDLE_FLAG_TIMER_STOP flag. The flag only affects CPU local timers. Cc: Anson Huang <anson.huang@nxp.com> Signed-off-by: Stefan Agner <stefan@agner.ch> Reviewed-by: Lucas Stach <l.stach@pengutronix.de> Signed-off-by: Shawn Guo <shawnguo@kernel.org>
117 lines
2.6 KiB
C
117 lines
2.6 KiB
C
/*
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* Copyright (C) 2014 Freescale Semiconductor, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/cpuidle.h>
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#include <linux/cpu_pm.h>
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#include <linux/module.h>
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#include <asm/cacheflush.h>
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#include <asm/cpuidle.h>
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#include <asm/suspend.h>
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#include "common.h"
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#include "cpuidle.h"
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static int imx6sx_idle_finish(unsigned long val)
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{
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/*
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* for Cortex-A7 which has an internal L2
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* cache, need to flush it before powering
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* down ARM platform, since flushing L1 cache
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* here again has very small overhead, compared
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* to adding conditional code for L2 cache type,
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* just call flush_cache_all() is fine.
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*/
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flush_cache_all();
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cpu_do_idle();
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return 0;
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}
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static int imx6sx_enter_wait(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int index)
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{
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imx6_set_lpm(WAIT_UNCLOCKED);
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switch (index) {
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case 1:
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cpu_do_idle();
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break;
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case 2:
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imx6_enable_rbc(true);
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imx_gpc_set_arm_power_in_lpm(true);
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imx_set_cpu_jump(0, v7_cpu_resume);
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/* Need to notify there is a cpu pm operation. */
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cpu_pm_enter();
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cpu_cluster_pm_enter();
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cpu_suspend(0, imx6sx_idle_finish);
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cpu_cluster_pm_exit();
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cpu_pm_exit();
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imx_gpc_set_arm_power_in_lpm(false);
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imx6_enable_rbc(false);
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break;
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default:
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break;
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}
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imx6_set_lpm(WAIT_CLOCKED);
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return index;
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}
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static struct cpuidle_driver imx6sx_cpuidle_driver = {
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.name = "imx6sx_cpuidle",
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.owner = THIS_MODULE,
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.states = {
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/* WFI */
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ARM_CPUIDLE_WFI_STATE,
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/* WAIT */
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{
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.exit_latency = 50,
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.target_residency = 75,
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.flags = CPUIDLE_FLAG_TIMER_STOP,
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.enter = imx6sx_enter_wait,
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.name = "WAIT",
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.desc = "Clock off",
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},
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/* WAIT + ARM power off */
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{
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/*
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* ARM gating 31us * 5 + RBC clear 65us
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* and some margin for SW execution, here set it
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* to 300us.
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*/
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.exit_latency = 300,
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.target_residency = 500,
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.flags = CPUIDLE_FLAG_TIMER_STOP,
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.enter = imx6sx_enter_wait,
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.name = "LOW-POWER-IDLE",
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.desc = "ARM power off",
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},
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},
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.state_count = 3,
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.safe_state_index = 0,
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};
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int __init imx6sx_cpuidle_init(void)
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{
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imx6_set_int_mem_clk_lpm(true);
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imx6_enable_rbc(false);
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/*
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* set ARM power up/down timing to the fastest,
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* sw2iso and sw can be set to one 32K cycle = 31us
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* except for power up sw2iso which need to be
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* larger than LDO ramp up time.
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*/
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imx_gpc_set_arm_power_up_timing(2, 1);
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imx_gpc_set_arm_power_down_timing(1, 1);
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return cpuidle_register(&imx6sx_cpuidle_driver, NULL);
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}
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