1/*
2 * Copyright (C) 2012-2013 Xilinx
3 *
4 * CPU idle support for Xilinx Zynq
5 *
6 * based on arch/arm/mach-at91/cpuidle.c
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms and conditions of the GNU General Public License,
10 * version 2, as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15 * more details.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * this program.  If not, see <http://www.gnu.org/licenses/>.
19 *
20 * The cpu idle uses wait-for-interrupt and RAM self refresh in order
21 * to implement two idle states -
22 * #1 wait-for-interrupt
23 * #2 wait-for-interrupt and RAM self refresh
24 *
25 * Maintainer: Michal Simek <michal.simek@xilinx.com>
26 */
27
28#include <linux/init.h>
29#include <linux/cpuidle.h>
30#include <linux/platform_device.h>
31#include <asm/cpuidle.h>
32
33#define ZYNQ_MAX_STATES		2
34
35/* Actual code that puts the SoC in different idle states */
36static int zynq_enter_idle(struct cpuidle_device *dev,
37			   struct cpuidle_driver *drv, int index)
38{
39	/* Add code for DDR self refresh start */
40	cpu_do_idle();
41
42	return index;
43}
44
45static struct cpuidle_driver zynq_idle_driver = {
46	.name = "zynq_idle",
47	.owner = THIS_MODULE,
48	.states = {
49		ARM_CPUIDLE_WFI_STATE,
50		{
51			.enter			= zynq_enter_idle,
52			.exit_latency		= 10,
53			.target_residency	= 10000,
54			.name			= "RAM_SR",
55			.desc			= "WFI and RAM Self Refresh",
56		},
57	},
58	.safe_state_index = 0,
59	.state_count = ZYNQ_MAX_STATES,
60};
61
62/* Initialize CPU idle by registering the idle states */
63static int zynq_cpuidle_probe(struct platform_device *pdev)
64{
65	pr_info("Xilinx Zynq CpuIdle Driver started\n");
66
67	return cpuidle_register(&zynq_idle_driver, NULL);
68}
69
70static struct platform_driver zynq_cpuidle_driver = {
71	.driver = {
72		.name = "cpuidle-zynq",
73	},
74	.probe = zynq_cpuidle_probe,
75};
76builtin_platform_driver(zynq_cpuidle_driver);
77