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
36 enum 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
43 static 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
50 static void __iomem *at91_shdwc_base;
51
at91_wakeup_status(void)52 static 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
at91_poweroff(void)69 static void at91_poweroff(void)
70 {
71 writel(AT91_SHDW_KEY | AT91_SHDW_SHDW, at91_shdwc_base + AT91_SHDW_CR);
72 }
73
at91_poweroff_get_wakeup_mode(struct device_node * np)74 const enum wakeup_type at91_poweroff_get_wakeup_mode(struct device_node *np)
75 {
76 const char *pm;
77 int err, i;
78
79 err = of_property_read_string(np, "atmel,wakeup-mode", &pm);
80 if (err < 0)
81 return AT91_SHDW_WKMODE0_ANYLEVEL;
82
83 for (i = 0; i < ARRAY_SIZE(shdwc_wakeup_modes); i++)
84 if (!strcasecmp(pm, shdwc_wakeup_modes[i]))
85 return i;
86
87 return -ENODEV;
88 }
89
at91_poweroff_dt_set_wakeup_mode(struct platform_device * pdev)90 static void at91_poweroff_dt_set_wakeup_mode(struct platform_device *pdev)
91 {
92 struct device_node *np = pdev->dev.of_node;
93 enum wakeup_type wakeup_mode;
94 u32 mode = 0, tmp;
95
96 wakeup_mode = at91_poweroff_get_wakeup_mode(np);
97 if (wakeup_mode < 0) {
98 dev_warn(&pdev->dev, "shdwc unknown wakeup mode\n");
99 return;
100 }
101
102 if (!of_property_read_u32(np, "atmel,wakeup-counter", &tmp)) {
103 if (tmp > AT91_SHDW_CPTWK0_MAX) {
104 dev_warn(&pdev->dev,
105 "shdwc wakeup counter 0x%x > 0x%x reduce it to 0x%x\n",
106 tmp, AT91_SHDW_CPTWK0_MAX, AT91_SHDW_CPTWK0_MAX);
107 tmp = AT91_SHDW_CPTWK0_MAX;
108 }
109 mode |= AT91_SHDW_CPTWK0_(tmp);
110 }
111
112 if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
113 mode |= AT91_SHDW_RTCWKEN;
114
115 if (of_property_read_bool(np, "atmel,wakeup-rtt-timer"))
116 mode |= AT91_SHDW_RTTWKEN;
117
118 writel(wakeup_mode | mode, at91_shdwc_base + AT91_SHDW_MR);
119 }
120
at91_poweroff_probe(struct platform_device * pdev)121 static int at91_poweroff_probe(struct platform_device *pdev)
122 {
123 struct resource *res;
124
125 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
126 at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
127 if (IS_ERR(at91_shdwc_base)) {
128 dev_err(&pdev->dev, "Could not map reset controller address\n");
129 return PTR_ERR(at91_shdwc_base);
130 }
131
132 at91_wakeup_status();
133
134 if (pdev->dev.of_node)
135 at91_poweroff_dt_set_wakeup_mode(pdev);
136
137 pm_power_off = at91_poweroff;
138
139 return 0;
140 }
141
142 static struct of_device_id at91_poweroff_of_match[] = {
143 { .compatible = "atmel,at91sam9260-shdwc", },
144 { .compatible = "atmel,at91sam9rl-shdwc", },
145 { .compatible = "atmel,at91sam9x5-shdwc", },
146 { /*sentinel*/ }
147 };
148
149 static struct platform_driver at91_poweroff_driver = {
150 .probe = at91_poweroff_probe,
151 .driver = {
152 .name = "at91-poweroff",
153 .of_match_table = at91_poweroff_of_match,
154 },
155 };
156 module_platform_driver(at91_poweroff_driver);
157