/* * 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/cpuidle.h> #include "cpuidle.h" #include "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, .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", }, }; static int __init davinci_cpuidle_init(void) { return platform_driver_probe(&davinci_cpuidle_driver, davinci_cpuidle_probe); } device_initcall(davinci_cpuidle_init);