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/cpuidle.h>
25
26#define KIRKWOOD_MAX_STATES	2
27
28static void __iomem *ddr_operation_base;
29
30/* Actual code that puts the SoC in different idle states */
31static 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
41static struct cpuidle_driver kirkwood_idle_driver = {
42	.name			= "kirkwood_idle",
43	.owner			= THIS_MODULE,
44	.states[0]		= ARM_CPUIDLE_WFI_STATE,
45	.states[1]		= {
46		.enter			= kirkwood_enter_idle,
47		.exit_latency		= 10,
48		.target_residency	= 100000,
49		.name			= "DDR SR",
50		.desc			= "WFI and DDR Self Refresh",
51	},
52	.state_count = KIRKWOOD_MAX_STATES,
53};
54
55/* Initialize CPU idle by registering the idle states */
56static int kirkwood_cpuidle_probe(struct platform_device *pdev)
57{
58	ddr_operation_base = devm_platform_ioremap_resource(pdev, 0);
59	if (IS_ERR(ddr_operation_base))
60		return PTR_ERR(ddr_operation_base);
61
62	return cpuidle_register(&kirkwood_idle_driver, NULL);
63}
64
65static int kirkwood_cpuidle_remove(struct platform_device *pdev)
66{
67	cpuidle_unregister(&kirkwood_idle_driver);
68	return 0;
69}
70
71static struct platform_driver kirkwood_cpuidle_driver = {
72	.probe = kirkwood_cpuidle_probe,
73	.remove = kirkwood_cpuidle_remove,
74	.driver = {
75		   .name = "kirkwood_cpuidle",
76		   },
77};
78
79module_platform_driver(kirkwood_cpuidle_driver);
80
81MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
82MODULE_DESCRIPTION("Kirkwood cpu idle driver");
83MODULE_LICENSE("GPL v2");
84MODULE_ALIAS("platform:kirkwood-cpuidle");
85