1/*
2 * Atmel AT91 SAM9 SoCs reset code
3 *
4 * Copyright (C) 2007 Atmel Corporation.
5 * Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
6 * Copyright (C) 2014 Free Electrons
7 *
8 * This file is licensed under the terms of the GNU General Public
9 * License version 2.  This program is licensed "as is" without any
10 * warranty of any kind, whether express or implied.
11 */
12
13#include <linux/io.h>
14#include <linux/module.h>
15#include <linux/of.h>
16#include <linux/platform_device.h>
17#include <linux/printk.h>
18
19#define AT91_SHDW_CR	0x00		/* Shut Down Control Register */
20#define AT91_SHDW_SHDW		BIT(0)			/* Shut Down command */
21#define AT91_SHDW_KEY		(0xa5 << 24)		/* KEY Password */
22
23#define AT91_SHDW_MR	0x04		/* Shut Down Mode Register */
24#define AT91_SHDW_WKMODE0	GENMASK(2, 0)		/* Wake-up 0 Mode Selection */
25#define AT91_SHDW_CPTWK0_MAX	0xf			/* Maximum Counter On Wake Up 0 */
26#define AT91_SHDW_CPTWK0	(AT91_SHDW_CPTWK0_MAX << 4) /* Counter On Wake Up 0 */
27#define AT91_SHDW_CPTWK0_(x)	((x) << 4)
28#define AT91_SHDW_RTTWKEN	BIT(16)			/* Real Time Timer Wake-up Enable */
29#define AT91_SHDW_RTCWKEN	BIT(17)			/* Real Time Clock Wake-up Enable */
30
31#define AT91_SHDW_SR	0x08		/* Shut Down Status Register */
32#define AT91_SHDW_WAKEUP0	BIT(0)			/* Wake-up 0 Status */
33#define AT91_SHDW_RTTWK		BIT(16)			/* Real-time Timer Wake-up */
34#define AT91_SHDW_RTCWK		BIT(17)			/* Real-time Clock Wake-up [SAM9RL] */
35
36enum wakeup_type {
37	AT91_SHDW_WKMODE0_NONE		= 0,
38	AT91_SHDW_WKMODE0_HIGH		= 1,
39	AT91_SHDW_WKMODE0_LOW		= 2,
40	AT91_SHDW_WKMODE0_ANYLEVEL	= 3,
41};
42
43static const char *shdwc_wakeup_modes[] = {
44	[AT91_SHDW_WKMODE0_NONE]	= "none",
45	[AT91_SHDW_WKMODE0_HIGH]	= "high",
46	[AT91_SHDW_WKMODE0_LOW]		= "low",
47	[AT91_SHDW_WKMODE0_ANYLEVEL]	= "any",
48};
49
50static void __iomem *at91_shdwc_base;
51
52static void __init at91_wakeup_status(void)
53{
54	u32 reg = readl(at91_shdwc_base + AT91_SHDW_SR);
55	char *reason = "unknown";
56
57	/* Simple power-on, just bail out */
58	if (!reg)
59		return;
60
61	if (reg & AT91_SHDW_RTTWK)
62		reason = "RTT";
63	else if (reg & AT91_SHDW_RTCWK)
64		reason = "RTC";
65
66	pr_info("AT91: Wake-Up source: %s\n", reason);
67}
68
69static void at91_poweroff(void)
70{
71	writel(AT91_SHDW_KEY | AT91_SHDW_SHDW, at91_shdwc_base + AT91_SHDW_CR);
72}
73
74static int at91_poweroff_get_wakeup_mode(struct device_node *np)
75{
76	const char *pm;
77	unsigned int i;
78	int err;
79
80	err = of_property_read_string(np, "atmel,wakeup-mode", &pm);
81	if (err < 0)
82		return AT91_SHDW_WKMODE0_ANYLEVEL;
83
84	for (i = 0; i < ARRAY_SIZE(shdwc_wakeup_modes); i++)
85		if (!strcasecmp(pm, shdwc_wakeup_modes[i]))
86			return i;
87
88	return -ENODEV;
89}
90
91static void at91_poweroff_dt_set_wakeup_mode(struct platform_device *pdev)
92{
93	struct device_node *np = pdev->dev.of_node;
94	int wakeup_mode;
95	u32 mode = 0, tmp;
96
97	wakeup_mode = at91_poweroff_get_wakeup_mode(np);
98	if (wakeup_mode < 0) {
99		dev_warn(&pdev->dev, "shdwc unknown wakeup mode\n");
100		return;
101	}
102
103	if (!of_property_read_u32(np, "atmel,wakeup-counter", &tmp)) {
104		if (tmp > AT91_SHDW_CPTWK0_MAX) {
105			dev_warn(&pdev->dev,
106				 "shdwc wakeup counter 0x%x > 0x%x reduce it to 0x%x\n",
107				 tmp, AT91_SHDW_CPTWK0_MAX, AT91_SHDW_CPTWK0_MAX);
108			tmp = AT91_SHDW_CPTWK0_MAX;
109		}
110		mode |= AT91_SHDW_CPTWK0_(tmp);
111	}
112
113	if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
114			mode |= AT91_SHDW_RTCWKEN;
115
116	if (of_property_read_bool(np, "atmel,wakeup-rtt-timer"))
117			mode |= AT91_SHDW_RTTWKEN;
118
119	writel(wakeup_mode | mode, at91_shdwc_base + AT91_SHDW_MR);
120}
121
122static int at91_poweroff_probe(struct platform_device *pdev)
123{
124	struct resource *res;
125
126	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
127	at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
128	if (IS_ERR(at91_shdwc_base)) {
129		dev_err(&pdev->dev, "Could not map reset controller address\n");
130		return PTR_ERR(at91_shdwc_base);
131	}
132
133	at91_wakeup_status();
134
135	if (pdev->dev.of_node)
136		at91_poweroff_dt_set_wakeup_mode(pdev);
137
138	pm_power_off = at91_poweroff;
139
140	return 0;
141}
142
143static const struct of_device_id at91_poweroff_of_match[] = {
144	{ .compatible = "atmel,at91sam9260-shdwc", },
145	{ .compatible = "atmel,at91sam9rl-shdwc", },
146	{ .compatible = "atmel,at91sam9x5-shdwc", },
147	{ /*sentinel*/ }
148};
149
150static struct platform_driver at91_poweroff_driver = {
151	.probe = at91_poweroff_probe,
152	.driver = {
153		.name = "at91-poweroff",
154		.of_match_table = at91_poweroff_of_match,
155	},
156};
157module_platform_driver(at91_poweroff_driver);
158