1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * CPU idle for DaVinci SoCs 4 * 5 * Copyright (C) 2009 Texas Instruments Incorporated. https://www.ti.com/ 6 * 7 * Derived from Marvell Kirkwood CPU idle code 8 * (arch/arm/mach-kirkwood/cpuidle.c) 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/init.h> 13 #include <linux/platform_device.h> 14 #include <linux/cpuidle.h> 15 #include <linux/io.h> 16 #include <linux/export.h> 17 #include <asm/cpuidle.h> 18 19 #include "cpuidle.h" 20 #include "ddr2.h" 21 22 #define DAVINCI_CPUIDLE_MAX_STATES 2 23 24 static void __iomem *ddr2_reg_base; 25 static bool ddr2_pdown; 26 27 static void davinci_save_ddr_power(int enter, bool pdown) 28 { 29 u32 val; 30 31 val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET); 32 33 if (enter) { 34 if (pdown) 35 val |= DDR2_SRPD_BIT; 36 else 37 val &= ~DDR2_SRPD_BIT; 38 val |= DDR2_LPMODEN_BIT; 39 } else { 40 val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT); 41 } 42 43 __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET); 44 } 45 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) 49 { 50 davinci_save_ddr_power(1, ddr2_pdown); 51 cpu_do_idle(); 52 davinci_save_ddr_power(0, ddr2_pdown); 53 54 return index; 55 } 56 57 static struct cpuidle_driver davinci_idle_driver = { 58 .name = "cpuidle-davinci", 59 .owner = THIS_MODULE, 60 .states[0] = ARM_CPUIDLE_WFI_STATE, 61 .states[1] = { 62 .enter = davinci_enter_idle, 63 .exit_latency = 10, 64 .target_residency = 10000, 65 .name = "DDR SR", 66 .desc = "WFI and DDR Self Refresh", 67 }, 68 .state_count = DAVINCI_CPUIDLE_MAX_STATES, 69 }; 70 71 static int __init davinci_cpuidle_probe(struct platform_device *pdev) 72 { 73 struct davinci_cpuidle_config *pdata = pdev->dev.platform_data; 74 75 if (!pdata) { 76 dev_err(&pdev->dev, "cannot get platform data\n"); 77 return -ENOENT; 78 } 79 80 ddr2_reg_base = pdata->ddr2_ctlr_base; 81 82 ddr2_pdown = pdata->ddr2_pdown; 83 84 return cpuidle_register(&davinci_idle_driver, NULL); 85 } 86 87 static struct platform_driver davinci_cpuidle_driver = { 88 .driver = { 89 .name = "cpuidle-davinci", 90 }, 91 }; 92 93 static int __init davinci_cpuidle_init(void) 94 { 95 return platform_driver_probe(&davinci_cpuidle_driver, 96 davinci_cpuidle_probe); 97 } 98 device_initcall(davinci_cpuidle_init); 99 100