106 lines
2.4 KiB
C
106 lines
2.4 KiB
C
/*
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* CPU idle for DaVinci SoCs
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*
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* Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/
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*
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* Derived from Marvell Kirkwood CPU idle code
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* (arch/arm/mach-kirkwood/cpuidle.c)
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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/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/cpuidle.h>
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#include <linux/io.h>
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#include <linux/export.h>
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#include <asm/proc-fns.h>
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#include <asm/cpuidle.h>
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#include <mach/cpuidle.h>
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#include <mach/ddr2.h>
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#define DAVINCI_CPUIDLE_MAX_STATES 2
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static void __iomem *ddr2_reg_base;
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static bool ddr2_pdown;
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static void davinci_save_ddr_power(int enter, bool pdown)
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{
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u32 val;
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val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET);
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if (enter) {
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if (pdown)
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val |= DDR2_SRPD_BIT;
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else
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val &= ~DDR2_SRPD_BIT;
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val |= DDR2_LPMODEN_BIT;
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} else {
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val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT);
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}
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__raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET);
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}
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/* Actual code that puts the SoC in different idle states */
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static int davinci_enter_idle(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int index)
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{
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davinci_save_ddr_power(1, ddr2_pdown);
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cpu_do_idle();
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davinci_save_ddr_power(0, ddr2_pdown);
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return index;
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}
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static struct cpuidle_driver davinci_idle_driver = {
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.name = "cpuidle-davinci",
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.owner = THIS_MODULE,
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.states[0] = ARM_CPUIDLE_WFI_STATE,
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.states[1] = {
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.enter = davinci_enter_idle,
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.exit_latency = 10,
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.target_residency = 10000,
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.flags = CPUIDLE_FLAG_TIME_VALID,
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.name = "DDR SR",
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.desc = "WFI and DDR Self Refresh",
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},
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.state_count = DAVINCI_CPUIDLE_MAX_STATES,
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};
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static int __init davinci_cpuidle_probe(struct platform_device *pdev)
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{
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struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
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if (!pdata) {
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dev_err(&pdev->dev, "cannot get platform data\n");
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return -ENOENT;
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}
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ddr2_reg_base = pdata->ddr2_ctlr_base;
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ddr2_pdown = pdata->ddr2_pdown;
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return cpuidle_register(&davinci_idle_driver, NULL);
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}
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static struct platform_driver davinci_cpuidle_driver = {
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.driver = {
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.name = "cpuidle-davinci",
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.owner = THIS_MODULE,
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},
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};
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static int __init davinci_cpuidle_init(void)
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{
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return platform_driver_probe(&davinci_cpuidle_driver,
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davinci_cpuidle_probe);
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}
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device_initcall(davinci_cpuidle_init);
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