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/proc-fns.h>
32#include <asm/cpuidle.h>
33
34#define ZYNQ_MAX_STATES		2
35
36/* Actual code that puts the SoC in different idle states */
37static int zynq_enter_idle(struct cpuidle_device *dev,
38			   struct cpuidle_driver *drv, int index)
39{
40	/* Add code for DDR self refresh start */
41	cpu_do_idle();
42
43	return index;
44}
45
46static struct cpuidle_driver zynq_idle_driver = {
47	.name = "zynq_idle",
48	.owner = THIS_MODULE,
49	.states = {
50		ARM_CPUIDLE_WFI_STATE,
51		{
52			.enter			= zynq_enter_idle,
53			.exit_latency		= 10,
54			.target_residency	= 10000,
55			.flags			= CPUIDLE_FLAG_TIME_VALID,
56			.name			= "RAM_SR",
57			.desc			= "WFI and RAM Self Refresh",
58		},
59	},
60	.safe_state_index = 0,
61	.state_count = ZYNQ_MAX_STATES,
62};
63
64/* Initialize CPU idle by registering the idle states */
65static int zynq_cpuidle_probe(struct platform_device *pdev)
66{
67	pr_info("Xilinx Zynq CpuIdle Driver started\n");
68
69	return cpuidle_register(&zynq_idle_driver, NULL);
70}
71
72static struct platform_driver zynq_cpuidle_driver = {
73	.driver = {
74		.name = "cpuidle-zynq",
75		.owner = THIS_MODULE,
76	},
77	.probe = zynq_cpuidle_probe,
78};
79
80module_platform_driver(zynq_cpuidle_driver);
81