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/cpuidle.h> 21 22 #include "cpuidle.h" 23 #include "ddr2.h" 24 25 #define DAVINCI_CPUIDLE_MAX_STATES 2 26 27 static void __iomem *ddr2_reg_base; 28 static bool ddr2_pdown; 29 30 static void davinci_save_ddr_power(int enter, bool pdown) 31 { 32 u32 val; 33 34 val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET); 35 36 if (enter) { 37 if (pdown) 38 val |= DDR2_SRPD_BIT; 39 else 40 val &= ~DDR2_SRPD_BIT; 41 val |= DDR2_LPMODEN_BIT; 42 } else { 43 val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT); 44 } 45 46 __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET); 47 } 48 49 /* Actual code that puts the SoC in different idle states */ 50 static int davinci_enter_idle(struct cpuidle_device *dev, 51 struct cpuidle_driver *drv, int index) 52 { 53 davinci_save_ddr_power(1, ddr2_pdown); 54 cpu_do_idle(); 55 davinci_save_ddr_power(0, ddr2_pdown); 56 57 return index; 58 } 59 60 static struct cpuidle_driver davinci_idle_driver = { 61 .name = "cpuidle-davinci", 62 .owner = THIS_MODULE, 63 .states[0] = ARM_CPUIDLE_WFI_STATE, 64 .states[1] = { 65 .enter = davinci_enter_idle, 66 .exit_latency = 10, 67 .target_residency = 10000, 68 .name = "DDR SR", 69 .desc = "WFI and DDR Self Refresh", 70 }, 71 .state_count = DAVINCI_CPUIDLE_MAX_STATES, 72 }; 73 74 static int __init davinci_cpuidle_probe(struct platform_device *pdev) 75 { 76 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data; 77 78 if (!pdata) { 79 dev_err(&pdev->dev, "cannot get platform data\n"); 80 return -ENOENT; 81 } 82 83 ddr2_reg_base = pdata->ddr2_ctlr_base; 84 85 ddr2_pdown = pdata->ddr2_pdown; 86 87 return cpuidle_register(&davinci_idle_driver, NULL); 88 } 89 90 static struct platform_driver davinci_cpuidle_driver = { 91 .driver = { 92 .name = "cpuidle-davinci", 93 }, 94 }; 95 96 static int __init davinci_cpuidle_init(void) 97 { 98 return platform_driver_probe(&davinci_cpuidle_driver, 99 davinci_cpuidle_probe); 100 } 101 device_initcall(davinci_cpuidle_init); 102 103