1 /* 2 * CPU idle for DaVinci SoCs 3 * 4 * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/ 5 * 6 * Derived from Marvell Kirkwood CPU idle code 7 * (arch/arm/mach-kirkwood/cpuidle.c) 8 * 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. 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/init.h> 16 #include <linux/platform_device.h> 17 #include <linux/cpuidle.h> 18 #include <linux/io.h> 19 #include <linux/export.h> 20 #include <asm/proc-fns.h> 21 #include <asm/cpuidle.h> 22 23 #include <mach/cpuidle.h> 24 #include <mach/ddr2.h> 25 26 #define DAVINCI_CPUIDLE_MAX_STATES 2 27 28 static void __iomem *ddr2_reg_base; 29 static bool ddr2_pdown; 30 31 static void davinci_save_ddr_power(int enter, bool pdown) 32 { 33 u32 val; 34 35 val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET); 36 37 if (enter) { 38 if (pdown) 39 val |= DDR2_SRPD_BIT; 40 else 41 val &= ~DDR2_SRPD_BIT; 42 val |= DDR2_LPMODEN_BIT; 43 } else { 44 val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT); 45 } 46 47 __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET); 48 } 49 50 /* Actual code that puts the SoC in different idle states */ 51 static int davinci_enter_idle(struct cpuidle_device *dev, 52 struct cpuidle_driver *drv, int index) 53 { 54 davinci_save_ddr_power(1, ddr2_pdown); 55 cpu_do_idle(); 56 davinci_save_ddr_power(0, ddr2_pdown); 57 58 return index; 59 } 60 61 static struct cpuidle_driver davinci_idle_driver = { 62 .name = "cpuidle-davinci", 63 .owner = THIS_MODULE, 64 .states[0] = ARM_CPUIDLE_WFI_STATE, 65 .states[1] = { 66 .enter = davinci_enter_idle, 67 .exit_latency = 10, 68 .target_residency = 10000, 69 .name = "DDR SR", 70 .desc = "WFI and DDR Self Refresh", 71 }, 72 .state_count = DAVINCI_CPUIDLE_MAX_STATES, 73 }; 74 75 static int __init davinci_cpuidle_probe(struct platform_device *pdev) 76 { 77 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data; 78 79 if (!pdata) { 80 dev_err(&pdev->dev, "cannot get platform data\n"); 81 return -ENOENT; 82 } 83 84 ddr2_reg_base = pdata->ddr2_ctlr_base; 85 86 ddr2_pdown = pdata->ddr2_pdown; 87 88 return cpuidle_register(&davinci_idle_driver, NULL); 89 } 90 91 static struct platform_driver davinci_cpuidle_driver = { 92 .driver = { 93 .name = "cpuidle-davinci", 94 }, 95 }; 96 97 static int __init davinci_cpuidle_init(void) 98 { 99 return platform_driver_probe(&davinci_cpuidle_driver, 100 davinci_cpuidle_probe); 101 } 102 device_initcall(davinci_cpuidle_init); 103 104