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