1 /*
2  * arch/arm/mach-kirkwood/cpuidle.c
3  *
4  * CPU idle Marvell Kirkwood SoCs
5  *
6  * This file is licensed under the terms of the GNU General Public
7  * License version 2.  This program is licensed "as is" without any
8  * warranty of any kind, whether express or implied.
9  *
10  * The cpu idle uses wait-for-interrupt and DDR self refresh in order
11  * to implement two idle states -
12  * #1 wait-for-interrupt
13  * #2 wait-for-interrupt and DDR self refresh
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/platform_device.h>
20 #include <linux/cpuidle.h>
21 #include <linux/io.h>
22 #include <linux/export.h>
23 #include <asm/proc-fns.h>
24 #include <asm/cpuidle.h>
25 
26 #define KIRKWOOD_MAX_STATES	2
27 
28 static void __iomem *ddr_operation_base;
29 
30 /* Actual code that puts the SoC in different idle states */
31 static int kirkwood_enter_idle(struct cpuidle_device *dev,
32 			       struct cpuidle_driver *drv,
33 			       int index)
34 {
35 	writel(0x7, ddr_operation_base);
36 	cpu_do_idle();
37 
38 	return index;
39 }
40 
41 static struct cpuidle_driver kirkwood_idle_driver = {
42 	.name			= "kirkwood_idle",
43 	.owner			= THIS_MODULE,
44 	.en_core_tk_irqen	= 1,
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 static struct cpuidle_device *device;
57 
58 static DEFINE_PER_CPU(struct cpuidle_device, kirkwood_cpuidle_device);
59 
60 /* Initialize CPU idle by registering the idle states */
61 static int kirkwood_cpuidle_probe(struct platform_device *pdev)
62 {
63 	struct resource *res;
64 
65 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
66 	if (res == NULL)
67 		return -EINVAL;
68 
69 	ddr_operation_base = devm_request_and_ioremap(&pdev->dev, res);
70 	if (!ddr_operation_base)
71 		return -EADDRNOTAVAIL;
72 
73 	device = &per_cpu(kirkwood_cpuidle_device, smp_processor_id());
74 	device->state_count = KIRKWOOD_MAX_STATES;
75 
76 	cpuidle_register_driver(&kirkwood_idle_driver);
77 	if (cpuidle_register_device(device)) {
78 		pr_err("kirkwood_init_cpuidle: Failed registering\n");
79 		return -EIO;
80 	}
81 	return 0;
82 }
83 
84 int kirkwood_cpuidle_remove(struct platform_device *pdev)
85 {
86 	cpuidle_unregister_device(device);
87 	cpuidle_unregister_driver(&kirkwood_idle_driver);
88 
89 	return 0;
90 }
91 
92 static struct platform_driver kirkwood_cpuidle_driver = {
93 	.probe = kirkwood_cpuidle_probe,
94 	.remove = kirkwood_cpuidle_remove,
95 	.driver = {
96 		   .name = "kirkwood_cpuidle",
97 		   .owner = THIS_MODULE,
98 		   },
99 };
100 
101 module_platform_driver(kirkwood_cpuidle_driver);
102 
103 MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
104 MODULE_DESCRIPTION("Kirkwood cpu idle driver");
105 MODULE_LICENSE("GPL v2");
106 MODULE_ALIAS("platform:kirkwood-cpuidle");
107