1 /* 2 * CPU idle Marvell Kirkwood SoCs 3 * 4 * This file is licensed under the terms of the GNU General Public 5 * License version 2. This program is licensed "as is" without any 6 * warranty of any kind, whether express or implied. 7 * 8 * The cpu idle uses wait-for-interrupt and DDR self refresh in order 9 * to implement two idle states - 10 * #1 wait-for-interrupt 11 * #2 wait-for-interrupt and DDR self refresh 12 * 13 * Maintainer: Jason Cooper <jason@lakedaemon.net> 14 * Maintainer: Andrew Lunn <andrew@lunn.ch> 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/init.h> 20 #include <linux/platform_device.h> 21 #include <linux/cpuidle.h> 22 #include <linux/io.h> 23 #include <linux/export.h> 24 #include <asm/proc-fns.h> 25 #include <asm/cpuidle.h> 26 27 #define KIRKWOOD_MAX_STATES 2 28 29 static void __iomem *ddr_operation_base; 30 31 /* Actual code that puts the SoC in different idle states */ 32 static int kirkwood_enter_idle(struct cpuidle_device *dev, 33 struct cpuidle_driver *drv, 34 int index) 35 { 36 writel(0x7, ddr_operation_base); 37 cpu_do_idle(); 38 39 return index; 40 } 41 42 static struct cpuidle_driver kirkwood_idle_driver = { 43 .name = "kirkwood_idle", 44 .owner = THIS_MODULE, 45 .states[0] = ARM_CPUIDLE_WFI_STATE, 46 .states[1] = { 47 .enter = kirkwood_enter_idle, 48 .exit_latency = 10, 49 .target_residency = 100000, 50 .flags = CPUIDLE_FLAG_TIME_VALID, 51 .name = "DDR SR", 52 .desc = "WFI and DDR Self Refresh", 53 }, 54 .state_count = KIRKWOOD_MAX_STATES, 55 }; 56 57 /* Initialize CPU idle by registering the idle states */ 58 static int kirkwood_cpuidle_probe(struct platform_device *pdev) 59 { 60 struct resource *res; 61 62 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 63 ddr_operation_base = devm_ioremap_resource(&pdev->dev, res); 64 if (IS_ERR(ddr_operation_base)) 65 return PTR_ERR(ddr_operation_base); 66 67 return cpuidle_register(&kirkwood_idle_driver, NULL); 68 } 69 70 static int kirkwood_cpuidle_remove(struct platform_device *pdev) 71 { 72 cpuidle_unregister(&kirkwood_idle_driver); 73 return 0; 74 } 75 76 static struct platform_driver kirkwood_cpuidle_driver = { 77 .probe = kirkwood_cpuidle_probe, 78 .remove = kirkwood_cpuidle_remove, 79 .driver = { 80 .name = "kirkwood_cpuidle", 81 .owner = THIS_MODULE, 82 }, 83 }; 84 85 module_platform_driver(kirkwood_cpuidle_driver); 86 87 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>"); 88 MODULE_DESCRIPTION("Kirkwood cpu idle driver"); 89 MODULE_LICENSE("GPL v2"); 90 MODULE_ALIAS("platform:kirkwood-cpuidle"); 91