[go: nahoru, domu]
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
29static void __iomem *ddr_operation_base;
30
31/* Actual code that puts the SoC in different idle states */
32static 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
42static 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 */
58static 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
70static int kirkwood_cpuidle_remove(struct platform_device *pdev)
71{
72	cpuidle_unregister(&kirkwood_idle_driver);
73	return 0;
74}
75
76static 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
85module_platform_driver(kirkwood_cpuidle_driver);
86
87MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
88MODULE_DESCRIPTION("Kirkwood cpu idle driver");
89MODULE_LICENSE("GPL v2");
90MODULE_ALIAS("platform:kirkwood-cpuidle");
91