1 // SPDX-License-Identifier: GPL-2.0-only
3 * CPU idle for DaVinci SoCs
5 * Copyright (C) 2009 Texas Instruments Incorporated. https://www.ti.com/
7 * Derived from Marvell Kirkwood CPU idle code
8 * (arch/arm/mach-kirkwood/cpuidle.c)
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/platform_device.h>
14 #include <linux/cpuidle.h>
16 #include <linux/export.h>
17 #include <asm/cpuidle.h>
22 #define DAVINCI_CPUIDLE_MAX_STATES 2
24 static void __iomem *ddr2_reg_base;
25 static bool ddr2_pdown;
27 static void davinci_save_ddr_power(int enter, bool pdown)
31 val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET);
37 val &= ~DDR2_SRPD_BIT;
38 val |= DDR2_LPMODEN_BIT;
40 val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT);
43 __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET);
46 /* Actual code that puts the SoC in different idle states */
47 static int davinci_enter_idle(struct cpuidle_device *dev,
48 struct cpuidle_driver *drv, int index)
50 davinci_save_ddr_power(1, ddr2_pdown);
52 davinci_save_ddr_power(0, ddr2_pdown);
57 static struct cpuidle_driver davinci_idle_driver = {
58 .name = "cpuidle-davinci",
60 .states[0] = ARM_CPUIDLE_WFI_STATE,
62 .enter = davinci_enter_idle,
64 .target_residency = 10000,
66 .desc = "WFI and DDR Self Refresh",
68 .state_count = DAVINCI_CPUIDLE_MAX_STATES,
71 static int __init davinci_cpuidle_probe(struct platform_device *pdev)
73 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
76 dev_err(&pdev->dev, "cannot get platform data\n");
80 ddr2_reg_base = pdata->ddr2_ctlr_base;
82 ddr2_pdown = pdata->ddr2_pdown;
84 return cpuidle_register(&davinci_idle_driver, NULL);
87 static struct platform_driver davinci_cpuidle_driver = {
89 .name = "cpuidle-davinci",
93 static int __init davinci_cpuidle_init(void)
95 return platform_driver_probe(&davinci_cpuidle_driver,
96 davinci_cpuidle_probe);
98 device_initcall(davinci_cpuidle_init);