/* * 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 <asm/proc-fns.h> #include <mach/cpuidle.h> #include <mach/memory.h> #define DAVINCI_CPUIDLE_MAX_STATES 2 struct davinci_ops { void (*enter) (u32 flags); void (*exit) (u32 flags); u32 flags; }; /* fields in davinci_ops.flags */ #define DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN BIT(0) static struct cpuidle_driver davinci_idle_driver = { .name = "cpuidle-davinci", .owner = THIS_MODULE, }; static DEFINE_PER_CPU(struct cpuidle_device, davinci_cpuidle_device); static void __iomem *ddr2_reg_base; 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); } static void davinci_c2state_enter(u32 flags) { davinci_save_ddr_power(1, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); } static void davinci_c2state_exit(u32 flags) { davinci_save_ddr_power(0, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); } static struct davinci_ops davinci_states[DAVINCI_CPUIDLE_MAX_STATES] = { [1] = { .enter = davinci_c2state_enter, .exit = davinci_c2state_exit, }, }; /* Actual code that puts the SoC in different idle states */ static int davinci_enter_idle(struct cpuidle_device *dev, struct cpuidle_state *state) { struct davinci_ops *ops = cpuidle_get_statedata(state); struct timeval before, after; int idle_time; local_irq_disable(); do_gettimeofday(&before); if (ops && ops->enter) ops->enter(ops->flags); /* Wait for interrupt state */ cpu_do_idle(); if (ops && ops->exit) ops->exit(ops->flags); do_gettimeofday(&after); local_irq_enable(); idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC + (after.tv_usec - before.tv_usec); return idle_time; } static int __init davinci_cpuidle_probe(struct platform_device *pdev) { int ret; struct cpuidle_device *device; struct davinci_cpuidle_config *pdata = pdev->dev.platform_data; device = &per_cpu(davinci_cpuidle_device, smp_processor_id()); if (!pdata) { dev_err(&pdev->dev, "cannot get platform data\n"); return -ENOENT; } ddr2_reg_base = pdata->ddr2_ctlr_base; ret = cpuidle_register_driver(&davinci_idle_driver); if (ret) { dev_err(&pdev->dev, "failed to register driver\n"); return ret; } /* Wait for interrupt state */ device->states[0].enter = davinci_enter_idle; device->states[0].exit_latency = 1; device->states[0].target_residency = 10000; device->states[0].flags = CPUIDLE_FLAG_TIME_VALID; strcpy(device->states[0].name, "WFI"); strcpy(device->states[0].desc, "Wait for interrupt"); /* Wait for interrupt and DDR self refresh state */ device->states[1].enter = davinci_enter_idle; device->states[1].exit_latency = 10; device->states[1].target_residency = 10000; device->states[1].flags = CPUIDLE_FLAG_TIME_VALID; strcpy(device->states[1].name, "DDR SR"); strcpy(device->states[1].desc, "WFI and DDR Self Refresh"); if (pdata->ddr2_pdown) davinci_states[1].flags |= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN; cpuidle_set_statedata(&device->states[1], &davinci_states[1]); device->state_count = DAVINCI_CPUIDLE_MAX_STATES; ret = cpuidle_register_device(device); if (ret) { dev_err(&pdev->dev, "failed to register device\n"); cpuidle_unregister_driver(&davinci_idle_driver); return ret; } return 0; } 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);