1/*
2 * CPU idle for DaVinci SoCs
3 *
4 * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/
5 *
6 * Derived from Marvell Kirkwood CPU idle code
7 * (arch/arm/mach-kirkwood/cpuidle.c)
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14#include <linux/kernel.h>
15#include <linux/init.h>
16#include <linux/platform_device.h>
17#include <linux/cpuidle.h>
18#include <linux/io.h>
19#include <linux/export.h>
20#include <asm/cpuidle.h>
21
22#include <mach/cpuidle.h>
23#include <mach/ddr2.h>
24
25#define DAVINCI_CPUIDLE_MAX_STATES	2
26
27static void __iomem *ddr2_reg_base;
28static bool ddr2_pdown;
29
30static void davinci_save_ddr_power(int enter, bool pdown)
31{
32	u32 val;
33
34	val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET);
35
36	if (enter) {
37		if (pdown)
38			val |= DDR2_SRPD_BIT;
39		else
40			val &= ~DDR2_SRPD_BIT;
41		val |= DDR2_LPMODEN_BIT;
42	} else {
43		val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT);
44	}
45
46	__raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET);
47}
48
49/* Actual code that puts the SoC in different idle states */
50static int davinci_enter_idle(struct cpuidle_device *dev,
51			      struct cpuidle_driver *drv, int index)
52{
53	davinci_save_ddr_power(1, ddr2_pdown);
54	cpu_do_idle();
55	davinci_save_ddr_power(0, ddr2_pdown);
56
57	return index;
58}
59
60static struct cpuidle_driver davinci_idle_driver = {
61	.name			= "cpuidle-davinci",
62	.owner			= THIS_MODULE,
63	.states[0]		= ARM_CPUIDLE_WFI_STATE,
64	.states[1]		= {
65		.enter			= davinci_enter_idle,
66		.exit_latency		= 10,
67		.target_residency	= 10000,
68		.name			= "DDR SR",
69		.desc			= "WFI and DDR Self Refresh",
70	},
71	.state_count = DAVINCI_CPUIDLE_MAX_STATES,
72};
73
74static int __init davinci_cpuidle_probe(struct platform_device *pdev)
75{
76	struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
77
78	if (!pdata) {
79		dev_err(&pdev->dev, "cannot get platform data\n");
80		return -ENOENT;
81	}
82
83	ddr2_reg_base = pdata->ddr2_ctlr_base;
84
85	ddr2_pdown = pdata->ddr2_pdown;
86
87	return cpuidle_register(&davinci_idle_driver, NULL);
88}
89
90static struct platform_driver davinci_cpuidle_driver = {
91	.driver = {
92		.name	= "cpuidle-davinci",
93	},
94};
95
96static int __init davinci_cpuidle_init(void)
97{
98	return platform_driver_probe(&davinci_cpuidle_driver,
99						davinci_cpuidle_probe);
100}
101device_initcall(davinci_cpuidle_init);
102
103