1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * CPU idle for DaVinci SoCs
4 *
5 * Copyright (C) 2009 Texas Instruments Incorporated. https://www.ti.com/
6 *
7 * Derived from Marvell Kirkwood CPU idle code
8 * (arch/arm/mach-kirkwood/cpuidle.c)
9 */
10
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/platform_device.h>
14#include <linux/cpuidle.h>
15#include <linux/io.h>
16#include <linux/export.h>
17#include <asm/cpuidle.h>
18
19#include "cpuidle.h"
20#include "ddr2.h"
21
22#define DAVINCI_CPUIDLE_MAX_STATES	2
23
24static void __iomem *ddr2_reg_base;
25static bool ddr2_pdown;
26
27static void davinci_save_ddr_power(int enter, bool pdown)
28{
29	u32 val;
30
31	val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET);
32
33	if (enter) {
34		if (pdown)
35			val |= DDR2_SRPD_BIT;
36		else
37			val &= ~DDR2_SRPD_BIT;
38		val |= DDR2_LPMODEN_BIT;
39	} else {
40		val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT);
41	}
42
43	__raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET);
44}
45
46/* Actual code that puts the SoC in different idle states */
47static __cpuidle int davinci_enter_idle(struct cpuidle_device *dev,
48					struct cpuidle_driver *drv, int index)
49{
50	davinci_save_ddr_power(1, ddr2_pdown);
51	cpu_do_idle();
52	davinci_save_ddr_power(0, ddr2_pdown);
53
54	return index;
55}
56
57static struct cpuidle_driver davinci_idle_driver = {
58	.name			= "cpuidle-davinci",
59	.owner			= THIS_MODULE,
60	.states[0]		= ARM_CPUIDLE_WFI_STATE,
61	.states[1]		= {
62		.enter			= davinci_enter_idle,
63		.exit_latency		= 10,
64		.target_residency	= 10000,
65		.name			= "DDR SR",
66		.desc			= "WFI and DDR Self Refresh",
67	},
68	.state_count = DAVINCI_CPUIDLE_MAX_STATES,
69};
70
71static int __init davinci_cpuidle_probe(struct platform_device *pdev)
72{
73	struct davinci_cpuidle_config *pdata = pdev->dev.platform_data;
74
75	if (!pdata) {
76		dev_err(&pdev->dev, "cannot get platform data\n");
77		return -ENOENT;
78	}
79
80	ddr2_reg_base = pdata->ddr2_ctlr_base;
81
82	ddr2_pdown = pdata->ddr2_pdown;
83
84	return cpuidle_register(&davinci_idle_driver, NULL);
85}
86
87static struct platform_driver davinci_cpuidle_driver = {
88	.driver = {
89		.name	= "cpuidle-davinci",
90	},
91};
92
93static int __init davinci_cpuidle_init(void)
94{
95	return platform_driver_probe(&davinci_cpuidle_driver,
96						davinci_cpuidle_probe);
97}
98device_initcall(davinci_cpuidle_init);
99
100