forked from Minki/linux
751f7e999a
Add cpuidle support for i.MX6SL, currently only support
two cpuidle levels(ARM wfi and WAIT mode), and add software
workaround for WAIT mode errata as below:
ERR005311 CCM: After exit from WAIT mode, unwanted interrupt(s) taken
during WAIT mode entry process could cause cache memory
corruption.
Software workaround:
To prevent this issue from occurring, software should ensure that
the ARM to IPG clock ratio is less than 12:5 (that is < 2.4x), before
entering WAIT mode.
Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
58 lines
1.2 KiB
C
58 lines
1.2 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/module.h>
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#include <asm/cpuidle.h>
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#include <asm/proc-fns.h>
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#include "common.h"
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#include "cpuidle.h"
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static int imx6sl_enter_wait(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int index)
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{
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imx6q_set_lpm(WAIT_UNCLOCKED);
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/*
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* Software workaround for ERR005311, see function
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* description for details.
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*/
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imx6sl_set_wait_clk(true);
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cpu_do_idle();
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imx6sl_set_wait_clk(false);
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imx6q_set_lpm(WAIT_CLOCKED);
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return index;
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}
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static struct cpuidle_driver imx6sl_cpuidle_driver = {
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.name = "imx6sl_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_TIME_VALID |
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CPUIDLE_FLAG_TIMER_STOP,
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.enter = imx6sl_enter_wait,
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.name = "WAIT",
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.desc = "Clock off",
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},
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},
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.state_count = 2,
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.safe_state_index = 0,
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};
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int __init imx6sl_cpuidle_init(void)
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{
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return cpuidle_register(&imx6sl_cpuidle_driver, NULL);
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}
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