2 * Driver for Atmel SAMA5D4 Watchdog Timer
4 * Copyright (C) 2015 Atmel Corporation
6 * Licensed under GPLv2.
9 #include <linux/interrupt.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
14 #include <linux/of_irq.h>
15 #include <linux/platform_device.h>
16 #include <linux/reboot.h>
17 #include <linux/watchdog.h>
19 #include "at91sam9_wdt.h"
21 /* minimum and maximum watchdog timeout, in seconds */
22 #define MIN_WDT_TIMEOUT 1
23 #define MAX_WDT_TIMEOUT 16
24 #define WDT_DEFAULT_TIMEOUT MAX_WDT_TIMEOUT
26 #define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0)
29 struct watchdog_device wdd
;
30 void __iomem
*reg_base
;
34 static int wdt_timeout
= WDT_DEFAULT_TIMEOUT
;
35 static bool nowayout
= WATCHDOG_NOWAYOUT
;
37 module_param(wdt_timeout
, int, 0);
38 MODULE_PARM_DESC(wdt_timeout
,
39 "Watchdog timeout in seconds. (default = "
40 __MODULE_STRING(WDT_DEFAULT_TIMEOUT
) ")");
42 module_param(nowayout
, bool, 0);
43 MODULE_PARM_DESC(nowayout
,
44 "Watchdog cannot be stopped once started (default="
45 __MODULE_STRING(WATCHDOG_NOWAYOUT
) ")");
47 #define wdt_enabled (!(wdt->mr & AT91_WDT_WDDIS))
49 #define wdt_read(wdt, field) \
50 readl_relaxed((wdt)->reg_base + (field))
52 #define wdt_write(wtd, field, val) \
53 writel_relaxed((val), (wdt)->reg_base + (field))
55 static int sama5d4_wdt_start(struct watchdog_device
*wdd
)
57 struct sama5d4_wdt
*wdt
= watchdog_get_drvdata(wdd
);
59 wdt
->mr
&= ~AT91_WDT_WDDIS
;
60 wdt_write(wdt
, AT91_WDT_MR
, wdt
->mr
);
65 static int sama5d4_wdt_stop(struct watchdog_device
*wdd
)
67 struct sama5d4_wdt
*wdt
= watchdog_get_drvdata(wdd
);
69 wdt
->mr
|= AT91_WDT_WDDIS
;
70 wdt_write(wdt
, AT91_WDT_MR
, wdt
->mr
);
75 static int sama5d4_wdt_ping(struct watchdog_device
*wdd
)
77 struct sama5d4_wdt
*wdt
= watchdog_get_drvdata(wdd
);
79 wdt_write(wdt
, AT91_WDT_CR
, AT91_WDT_KEY
| AT91_WDT_WDRSTT
);
84 static int sama5d4_wdt_set_timeout(struct watchdog_device
*wdd
,
87 struct sama5d4_wdt
*wdt
= watchdog_get_drvdata(wdd
);
88 u32 value
= WDT_SEC2TICKS(timeout
);
90 wdt
->mr
&= ~AT91_WDT_WDV
;
91 wdt
->mr
&= ~AT91_WDT_WDD
;
92 wdt
->mr
|= AT91_WDT_SET_WDV(value
);
93 wdt
->mr
|= AT91_WDT_SET_WDD(value
);
96 * WDDIS has to be 0 when updating WDD/WDV. The datasheet states: When
97 * setting the WDDIS bit, and while it is set, the fields WDV and WDD
98 * must not be modified.
99 * If the watchdog is enabled, then the timeout can be updated. Else,
100 * wait that the user enables it.
103 wdt_write(wdt
, AT91_WDT_MR
, wdt
->mr
& ~AT91_WDT_WDDIS
);
105 wdd
->timeout
= timeout
;
110 static const struct watchdog_info sama5d4_wdt_info
= {
111 .options
= WDIOF_SETTIMEOUT
| WDIOF_MAGICCLOSE
| WDIOF_KEEPALIVEPING
,
112 .identity
= "Atmel SAMA5D4 Watchdog",
115 static const struct watchdog_ops sama5d4_wdt_ops
= {
116 .owner
= THIS_MODULE
,
117 .start
= sama5d4_wdt_start
,
118 .stop
= sama5d4_wdt_stop
,
119 .ping
= sama5d4_wdt_ping
,
120 .set_timeout
= sama5d4_wdt_set_timeout
,
123 static irqreturn_t
sama5d4_wdt_irq_handler(int irq
, void *dev_id
)
125 struct sama5d4_wdt
*wdt
= platform_get_drvdata(dev_id
);
127 if (wdt_read(wdt
, AT91_WDT_SR
)) {
128 pr_crit("Atmel Watchdog Software Reset\n");
130 pr_crit("Reboot didn't succeed\n");
136 static int of_sama5d4_wdt_init(struct device_node
*np
, struct sama5d4_wdt
*wdt
)
140 wdt
->mr
= AT91_WDT_WDDIS
;
142 if (!of_property_read_string(np
, "atmel,watchdog-type", &tmp
) &&
143 !strcmp(tmp
, "software"))
144 wdt
->mr
|= AT91_WDT_WDFIEN
;
146 wdt
->mr
|= AT91_WDT_WDRSTEN
;
148 if (of_property_read_bool(np
, "atmel,idle-halt"))
149 wdt
->mr
|= AT91_WDT_WDIDLEHLT
;
151 if (of_property_read_bool(np
, "atmel,dbg-halt"))
152 wdt
->mr
|= AT91_WDT_WDDBGHLT
;
157 static int sama5d4_wdt_init(struct sama5d4_wdt
*wdt
)
161 * When booting and resuming, the bootloader may have changed the
162 * watchdog configuration.
163 * If the watchdog is already running, we can safely update it.
164 * Else, we have to disable it properly.
167 wdt_write(wdt
, AT91_WDT_MR
, wdt
->mr
);
169 reg
= wdt_read(wdt
, AT91_WDT_MR
);
170 if (!(reg
& AT91_WDT_WDDIS
))
171 wdt_write(wdt
, AT91_WDT_MR
, reg
| AT91_WDT_WDDIS
);
176 static int sama5d4_wdt_probe(struct platform_device
*pdev
)
178 struct watchdog_device
*wdd
;
179 struct sama5d4_wdt
*wdt
;
180 struct resource
*res
;
186 wdt
= devm_kzalloc(&pdev
->dev
, sizeof(*wdt
), GFP_KERNEL
);
191 wdd
->timeout
= wdt_timeout
;
192 wdd
->info
= &sama5d4_wdt_info
;
193 wdd
->ops
= &sama5d4_wdt_ops
;
194 wdd
->min_timeout
= MIN_WDT_TIMEOUT
;
195 wdd
->max_timeout
= MAX_WDT_TIMEOUT
;
197 watchdog_set_drvdata(wdd
, wdt
);
199 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
200 regs
= devm_ioremap_resource(&pdev
->dev
, res
);
202 return PTR_ERR(regs
);
204 wdt
->reg_base
= regs
;
206 if (pdev
->dev
.of_node
) {
207 irq
= irq_of_parse_and_map(pdev
->dev
.of_node
, 0);
209 dev_warn(&pdev
->dev
, "failed to get IRQ from DT\n");
211 ret
= of_sama5d4_wdt_init(pdev
->dev
.of_node
, wdt
);
216 if ((wdt
->mr
& AT91_WDT_WDFIEN
) && irq
) {
217 ret
= devm_request_irq(&pdev
->dev
, irq
, sama5d4_wdt_irq_handler
,
218 IRQF_SHARED
| IRQF_IRQPOLL
|
219 IRQF_NO_SUSPEND
, pdev
->name
, pdev
);
222 "cannot register interrupt handler\n");
227 ret
= watchdog_init_timeout(wdd
, wdt_timeout
, &pdev
->dev
);
229 dev_err(&pdev
->dev
, "unable to set timeout value\n");
233 timeout
= WDT_SEC2TICKS(wdd
->timeout
);
235 wdt
->mr
|= AT91_WDT_SET_WDD(timeout
);
236 wdt
->mr
|= AT91_WDT_SET_WDV(timeout
);
238 ret
= sama5d4_wdt_init(wdt
);
242 watchdog_set_nowayout(wdd
, nowayout
);
244 ret
= watchdog_register_device(wdd
);
246 dev_err(&pdev
->dev
, "failed to register watchdog device\n");
250 platform_set_drvdata(pdev
, wdt
);
252 dev_info(&pdev
->dev
, "initialized (timeout = %d sec, nowayout = %d)\n",
253 wdt_timeout
, nowayout
);
258 static int sama5d4_wdt_remove(struct platform_device
*pdev
)
260 struct sama5d4_wdt
*wdt
= platform_get_drvdata(pdev
);
262 sama5d4_wdt_stop(&wdt
->wdd
);
264 watchdog_unregister_device(&wdt
->wdd
);
269 static const struct of_device_id sama5d4_wdt_of_match
[] = {
270 { .compatible
= "atmel,sama5d4-wdt", },
273 MODULE_DEVICE_TABLE(of
, sama5d4_wdt_of_match
);
275 #ifdef CONFIG_PM_SLEEP
276 static int sama5d4_wdt_resume(struct device
*dev
)
278 struct sama5d4_wdt
*wdt
= dev_get_drvdata(dev
);
280 sama5d4_wdt_init(wdt
);
286 static SIMPLE_DEV_PM_OPS(sama5d4_wdt_pm_ops
, NULL
,
289 static struct platform_driver sama5d4_wdt_driver
= {
290 .probe
= sama5d4_wdt_probe
,
291 .remove
= sama5d4_wdt_remove
,
293 .name
= "sama5d4_wdt",
294 .pm
= &sama5d4_wdt_pm_ops
,
295 .of_match_table
= sama5d4_wdt_of_match
,
298 module_platform_driver(sama5d4_wdt_driver
);
300 MODULE_AUTHOR("Atmel Corporation");
301 MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
302 MODULE_LICENSE("GPL v2");