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 */
kirkwood_enter_idle(struct cpuidle_device * dev,struct cpuidle_driver * drv,int index)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 */
kirkwood_cpuidle_probe(struct platform_device * pdev)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
kirkwood_cpuidle_remove(struct platform_device * pdev)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