2 * CPU idle for DaVinci SoCs
4 * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/
6 * Derived from Marvell Kirkwood CPU idle code
7 * (arch/arm/mach-kirkwood/cpuidle.c)
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/platform_device.h>
17 #include <linux/cpuidle.h>
19 #include <linux/export.h>
20 #include <asm/proc-fns.h>
21 #include <asm/cpuidle.h>
23 #include <mach/cpuidle.h>
24 #include <mach/ddr2.h>
26 #define DAVINCI_CPUIDLE_MAX_STATES 2
28 static DEFINE_PER_CPU(struct cpuidle_device, davinci_cpuidle_device);
29 static void __iomem *ddr2_reg_base;
30 static bool ddr2_pdown;
32 static void davinci_save_ddr_power(int enter, bool pdown)
36 val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET);
42 val &= ~DDR2_SRPD_BIT;
43 val |= DDR2_LPMODEN_BIT;
45 val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT);
48 __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET);
51 /* Actual code that puts the SoC in different idle states */
52 static int davinci_enter_idle(struct cpuidle_device *dev,
53 struct cpuidle_driver *drv,
56 davinci_save_ddr_power(1, ddr2_pdown);
58 index = cpuidle_wrap_enter(dev, drv, index,
59 arm_cpuidle_simple_enter);
61 davinci_save_ddr_power(0, ddr2_pdown);
66 static struct cpuidle_driver davinci_idle_driver = {
67 .name = "cpuidle-davinci",
69 .en_core_tk_irqen = 1,
70 .states[0] = ARM_CPUIDLE_WFI_STATE,
72 .enter = davinci_enter_idle,
74 .target_residency = 100000,
75 .flags = CPUIDLE_FLAG_TIME_VALID,
77 .desc = "WFI and DDR Self Refresh",
79 .state_count = DAVINCI_CPUIDLE_MAX_STATES,
82 static int __init davinci_cpuidle_probe(struct platform_device *pdev)
85 struct cpuidle_device *device;
86 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
88 device = &per_cpu(davinci_cpuidle_device, smp_processor_id());
91 dev_err(&pdev->dev, "cannot get platform data\n");
95 ddr2_reg_base = pdata->ddr2_ctlr_base;
97 ddr2_pdown = pdata->ddr2_pdown;
99 ret = cpuidle_register_driver(&davinci_idle_driver);
101 dev_err(&pdev->dev, "failed to register driver\n");
105 ret = cpuidle_register_device(device);
107 dev_err(&pdev->dev, "failed to register device\n");
108 cpuidle_unregister_driver(&davinci_idle_driver);
115 static struct platform_driver davinci_cpuidle_driver = {
117 .name = "cpuidle-davinci",
118 .owner = THIS_MODULE,
122 static int __init davinci_cpuidle_init(void)
124 return platform_driver_probe(&davinci_cpuidle_driver,
125 davinci_cpuidle_probe);
127 device_initcall(davinci_cpuidle_init);