1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * CPU idle Marvell Kirkwood SoCs 4 * 5 * The cpu idle uses wait-for-interrupt and DDR self refresh in order 6 * to implement two idle states - 7 * #1 wait-for-interrupt 8 * #2 wait-for-interrupt and DDR self refresh 9 * 10 * Maintainer: Jason Cooper <jason@lakedaemon.net> 11 * Maintainer: Andrew Lunn <andrew@lunn.ch> 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/init.h> 17 #include <linux/platform_device.h> 18 #include <linux/cpuidle.h> 19 #include <linux/io.h> 20 #include <linux/export.h> 21 #include <asm/cpuidle.h> 22 23 #define KIRKWOOD_MAX_STATES 2 24 25 static void __iomem *ddr_operation_base; 26 27 /* Actual code that puts the SoC in different idle states */ 28 static int kirkwood_enter_idle(struct cpuidle_device *dev, 29 struct cpuidle_driver *drv, 30 int index) 31 { 32 writel(0x7, ddr_operation_base); 33 cpu_do_idle(); 34 35 return index; 36 } 37 38 static struct cpuidle_driver kirkwood_idle_driver = { 39 .name = "kirkwood_idle", 40 .owner = THIS_MODULE, 41 .states[0] = ARM_CPUIDLE_WFI_STATE, 42 .states[1] = { 43 .enter = kirkwood_enter_idle, 44 .exit_latency = 10, 45 .target_residency = 100000, 46 .name = "DDR SR", 47 .desc = "WFI and DDR Self Refresh", 48 }, 49 .state_count = KIRKWOOD_MAX_STATES, 50 }; 51 52 /* Initialize CPU idle by registering the idle states */ 53 static int kirkwood_cpuidle_probe(struct platform_device *pdev) 54 { 55 ddr_operation_base = devm_platform_ioremap_resource(pdev, 0); 56 if (IS_ERR(ddr_operation_base)) 57 return PTR_ERR(ddr_operation_base); 58 59 return cpuidle_register(&kirkwood_idle_driver, NULL); 60 } 61 62 static int kirkwood_cpuidle_remove(struct platform_device *pdev) 63 { 64 cpuidle_unregister(&kirkwood_idle_driver); 65 return 0; 66 } 67 68 static struct platform_driver kirkwood_cpuidle_driver = { 69 .probe = kirkwood_cpuidle_probe, 70 .remove = kirkwood_cpuidle_remove, 71 .driver = { 72 .name = "kirkwood_cpuidle", 73 }, 74 }; 75 76 module_platform_driver(kirkwood_cpuidle_driver); 77 78 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>"); 79 MODULE_DESCRIPTION("Kirkwood cpu idle driver"); 80 MODULE_LICENSE("GPL v2"); 81 MODULE_ALIAS("platform:kirkwood-cpuidle"); 82