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
25static void __iomem *ddr_operation_base;
26
27/* Actual code that puts the SoC in different idle states */
28static 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
38static 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 */
53static 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
62static int kirkwood_cpuidle_remove(struct platform_device *pdev)
63{
64	cpuidle_unregister(&kirkwood_idle_driver);
65	return 0;
66}
67
68static 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
76module_platform_driver(kirkwood_cpuidle_driver);
77
78MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
79MODULE_DESCRIPTION("Kirkwood cpu idle driver");
80MODULE_LICENSE("GPL v2");
81MODULE_ALIAS("platform:kirkwood-cpuidle");
82