watchdog: Add Broadcom BCM2835 watchdog timer driver

This adds a driver for watchdog timer hardware present on Broadcom BCM2835 SoC, used in Raspberry Pi and Roku 2 devices. Signed-off-by: Lubomir Rintel <lkundrak@v3.sk> Tested-by: Stephen Warren <swarren@wwwdotorg.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Cc: linux-rpi-kernel@lists.infradead.org Cc: linux-watchdog@vger.kernel.org Cc: devicetree-discuss@lists.ozlabs.org

watchdog: Add Broadcom BCM2835 watchdog timer driver
This adds a driver for watchdog timer hardware present on Broadcom BCM2835 SoC, used in Raspberry Pi and Roku 2 devices. Signed-off-by: Lubomir Rintel <lkundrak@v3.sk> Tested-by: Stephen Warren <swarren@wwwdotorg.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Cc: linux-rpi-kernel@lists.infradead.org Cc: linux-watchdog@vger.kernel.org Cc: devicetree-discuss@lists.ozlabs.org
Lubomir Rintel · Wim Van Sebroeck
1 parent 6e63a3a294
Showing 4 changed files with 206 additions and 0 deletions Side-by-side Diff
Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt
drivers/watchdog/Kconfig
drivers/watchdog/Makefile
drivers/watchdog/bcm2835_wdt.c
@@ -5,10 +5,15 @@
 - compatible : should be "brcm,bcm2835-pm-wdt"
 - reg : Specifies base physical address and size of the registers.
  
+Optional properties:
+
+- timeout-sec   : Contains the watchdog timeout in seconds
+
 Example:
  
 watchdog {
 	compatible = "brcm,bcm2835-pm-wdt";
 	reg = <0x7e100000 0x28>;
+	timeout-sec = <10>;
 };
@@ -1100,6 +1100,17 @@
 	  To compile this driver as a loadable module, choose M here.
 	  The module will be called bcm63xx_wdt.
  
+config BCM2835_WDT
+	tristate "Broadcom BCM2835 hardware watchdog"
+	depends on ARCH_BCM2835
+	select WATCHDOG_CORE
+	help
+	  Watchdog driver for the built in watchdog hardware in Broadcom
+	  BCM2835 SoC.
+
+	  To compile this driver as a loadable module, choose M here.
+	  The module will be called bcm2835_wdt.
+
 config LANTIQ_WDT
 	tristate "Lantiq SoC watchdog"
 	depends on LANTIQ
@@ -53,6 +53,7 @@
 obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
 obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
 obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
+obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
  
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
+/*
+ * Watchdog driver for Broadcom BCM2835
+ *
+ * "bcm2708_wdog" driver written by Luke Diamand that was obtained from
+ * branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used
+ * as a hardware reference for the Broadcom BCM2835 watchdog timer.
+ *
+ * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/miscdevice.h>
+
+#define PM_RSTC				0x1c
+#define PM_WDOG				0x24
+
+#define PM_PASSWORD			0x5a000000
+
+#define PM_WDOG_TIME_SET		0x000fffff
+#define PM_RSTC_WRCFG_CLR		0xffffffcf
+#define PM_RSTC_WRCFG_SET		0x00000030
+#define PM_RSTC_WRCFG_FULL_RESET	0x00000020
+#define PM_RSTC_RESET			0x00000102
+
+#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
+#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
+
+struct bcm2835_wdt {
+	void __iomem		*base;
+	spinlock_t		lock;
+};
+
+static unsigned int heartbeat;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+static int bcm2835_wdt_start(struct watchdog_device *wdog)
+{
+	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
+	uint32_t cur;
+	unsigned long flags;
+
+	spin_lock_irqsave(&wdt->lock, flags);
+
+	writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) &
+				PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
+	cur = readl_relaxed(wdt->base + PM_RSTC);
+	writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
+		  PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
+
+	spin_unlock_irqrestore(&wdt->lock, flags);
+
+	return 0;
+}
+
+static int bcm2835_wdt_stop(struct watchdog_device *wdog)
+{
+	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
+
+	writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC);
+	dev_info(wdog->dev, "Watchdog timer stopped");
+	return 0;
+}
+
+static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
+{
+	wdog->timeout = t;
+	return 0;
+}
+
+static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
+{
+	struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
+
+	uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
+	return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
+}
+
+static struct watchdog_ops bcm2835_wdt_ops = {
+	.owner =	THIS_MODULE,
+	.start =	bcm2835_wdt_start,
+	.stop =		bcm2835_wdt_stop,
+	.set_timeout =	bcm2835_wdt_set_timeout,
+	.get_timeleft =	bcm2835_wdt_get_timeleft,
+};
+
+static struct watchdog_info bcm2835_wdt_info = {
+	.options =	WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
+			WDIOF_KEEPALIVEPING,
+	.identity =	"Broadcom BCM2835 Watchdog timer",
+};
+
+static struct watchdog_device bcm2835_wdt_wdd = {
+	.info =		&bcm2835_wdt_info,
+	.ops =		&bcm2835_wdt_ops,
+	.min_timeout =	1,
+	.max_timeout =	WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
+	.timeout =	WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
+};
+
+static int bcm2835_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct bcm2835_wdt *wdt;
+	int err;
+
+	wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
+	if (!wdt) {
+		dev_err(dev, "Failed to allocate memory for watchdog device");
+		return -ENOMEM;
+	}
+	platform_set_drvdata(pdev, wdt);
+
+	spin_lock_init(&wdt->lock);
+
+	wdt->base = of_iomap(np, 0);
+	if (!wdt->base) {
+		dev_err(dev, "Failed to remap watchdog regs");
+		return -ENODEV;
+	}
+
+	watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
+	watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
+	watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
+	err = watchdog_register_device(&bcm2835_wdt_wdd);
+	if (err) {
+		dev_err(dev, "Failed to register watchdog device");
+		iounmap(wdt->base);
+		return err;
+	}
+
+	dev_info(dev, "Broadcom BCM2835 watchdog timer");
+	return 0;
+}
+
+static int bcm2835_wdt_remove(struct platform_device *pdev)
+{
+	struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
+
+	watchdog_unregister_device(&bcm2835_wdt_wdd);
+	iounmap(wdt->base);
+
+	return 0;
+}
+
+static void bcm2835_wdt_shutdown(struct platform_device *pdev)
+{
+	bcm2835_wdt_stop(&bcm2835_wdt_wdd);
+}
+
+static const struct of_device_id bcm2835_wdt_of_match[] = {
+	{ .compatible = "brcm,bcm2835-pm-wdt", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
+
+static struct platform_driver bcm2835_wdt_driver = {
+	.probe		= bcm2835_wdt_probe,
+	.remove		= bcm2835_wdt_remove,
+	.shutdown	= bcm2835_wdt_shutdown,
+	.driver = {
+		.name =		"bcm2835-wdt",
+		.owner =	THIS_MODULE,
+		.of_match_table = bcm2835_wdt_of_match,
+	},
+};
+module_platform_driver(bcm2835_wdt_driver);
+
+module_param(heartbeat, uint, 0);
+MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
+
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
+MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
...	...	@@ -5,10 +5,15 @@
5	5	- compatible : should be "brcm,bcm2835-pm-wdt"
6	6	- reg : Specifies base physical address and size of the registers.
7	7
	8	+Optional properties:
	9	+
	10	+- timeout-sec : Contains the watchdog timeout in seconds
	11	+
8	12	Example:
9	13
10	14	watchdog {
11	15	compatible = "brcm,bcm2835-pm-wdt";
12	16	reg = <0x7e100000 0x28>;
	17	+ timeout-sec = <10>;
13	18	};
...	...	@@ -1100,6 +1100,17 @@
1100	1100	To compile this driver as a loadable module, choose M here.
1101	1101	The module will be called bcm63xx_wdt.
1102	1102
	1103	+config BCM2835_WDT
	1104	+ tristate "Broadcom BCM2835 hardware watchdog"
	1105	+ depends on ARCH_BCM2835
	1106	+ select WATCHDOG_CORE
	1107	+ help
	1108	+ Watchdog driver for the built in watchdog hardware in Broadcom
	1109	+ BCM2835 SoC.
	1110	+
	1111	+ To compile this driver as a loadable module, choose M here.
	1112	+ The module will be called bcm2835_wdt.
	1113	+
1103	1114	config LANTIQ_WDT
1104	1115	tristate "Lantiq SoC watchdog"
1105	1116	depends on LANTIQ
...	...	@@ -53,6 +53,7 @@
53	53	obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
54	54	obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
55	55	obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
	56	+obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
56	57
57	58	# AVR32 Architecture
58	59	obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
	1	+/*
	2	+ * Watchdog driver for Broadcom BCM2835
	3	+ *
	4	+ * "bcm2708_wdog" driver written by Luke Diamand that was obtained from
	5	+ * branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used
	6	+ * as a hardware reference for the Broadcom BCM2835 watchdog timer.
	7	+ *
	8	+ * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk>
	9	+ *
	10	+ * This program is free software; you can redistribute it and/or modify it
	11	+ * under the terms of the GNU General Public License as published by the
	12	+ * Free Software Foundation; either version 2 of the License, or (at your
	13	+ * option) any later version.
	14	+ */
	15	+
	16	+#include <linux/types.h>
	17	+#include <linux/module.h>
	18	+#include <linux/io.h>
	19	+#include <linux/watchdog.h>
	20	+#include <linux/platform_device.h>
	21	+#include <linux/of_address.h>
	22	+#include <linux/miscdevice.h>
	23	+
	24	+#define PM_RSTC 0x1c
	25	+#define PM_WDOG 0x24
	26	+
	27	+#define PM_PASSWORD 0x5a000000
	28	+
	29	+#define PM_WDOG_TIME_SET 0x000fffff
	30	+#define PM_RSTC_WRCFG_CLR 0xffffffcf
	31	+#define PM_RSTC_WRCFG_SET 0x00000030
	32	+#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
	33	+#define PM_RSTC_RESET 0x00000102
	34	+
	35	+#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
	36	+#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
	37	+
	38	+struct bcm2835_wdt {
	39	+ void __iomem *base;
	40	+ spinlock_t lock;
	41	+};
	42	+
	43	+static unsigned int heartbeat;
	44	+static bool nowayout = WATCHDOG_NOWAYOUT;
	45	+
	46	+static int bcm2835_wdt_start(struct watchdog_device *wdog)
	47	+{
	48	+ struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
	49	+ uint32_t cur;
	50	+ unsigned long flags;
	51	+
	52	+ spin_lock_irqsave(&wdt->lock, flags);
	53	+
	54	+ writel_relaxed(PM_PASSWORD \| (SECS_TO_WDOG_TICKS(wdog->timeout) &
	55	+ PM_WDOG_TIME_SET), wdt->base + PM_WDOG);
	56	+ cur = readl_relaxed(wdt->base + PM_RSTC);
	57	+ writel_relaxed(PM_PASSWORD \| (cur & PM_RSTC_WRCFG_CLR) \|
	58	+ PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC);
	59	+
	60	+ spin_unlock_irqrestore(&wdt->lock, flags);
	61	+
	62	+ return 0;
	63	+}
	64	+
	65	+static int bcm2835_wdt_stop(struct watchdog_device *wdog)
	66	+{
	67	+ struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
	68	+
	69	+ writel_relaxed(PM_PASSWORD \| PM_RSTC_RESET, wdt->base + PM_RSTC);
	70	+ dev_info(wdog->dev, "Watchdog timer stopped");
	71	+ return 0;
	72	+}
	73	+
	74	+static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
	75	+{
	76	+ wdog->timeout = t;
	77	+ return 0;
	78	+}
	79	+
	80	+static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
	81	+{
	82	+ struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
	83	+
	84	+ uint32_t ret = readl_relaxed(wdt->base + PM_WDOG);
	85	+ return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
	86	+}
	87	+
	88	+static struct watchdog_ops bcm2835_wdt_ops = {
	89	+ .owner = THIS_MODULE,
	90	+ .start = bcm2835_wdt_start,
	91	+ .stop = bcm2835_wdt_stop,
	92	+ .set_timeout = bcm2835_wdt_set_timeout,
	93	+ .get_timeleft = bcm2835_wdt_get_timeleft,
	94	+};
	95	+
	96	+static struct watchdog_info bcm2835_wdt_info = {
	97	+ .options = WDIOF_SETTIMEOUT \| WDIOF_MAGICCLOSE \|
	98	+ WDIOF_KEEPALIVEPING,
	99	+ .identity = "Broadcom BCM2835 Watchdog timer",
	100	+};
	101	+
	102	+static struct watchdog_device bcm2835_wdt_wdd = {
	103	+ .info = &bcm2835_wdt_info,
	104	+ .ops = &bcm2835_wdt_ops,
	105	+ .min_timeout = 1,
	106	+ .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
	107	+ .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
	108	+};
	109	+
	110	+static int bcm2835_wdt_probe(struct platform_device *pdev)
	111	+{
	112	+ struct device *dev = &pdev->dev;
	113	+ struct device_node *np = dev->of_node;
	114	+ struct bcm2835_wdt *wdt;
	115	+ int err;
	116	+
	117	+ wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL);
	118	+ if (!wdt) {
	119	+ dev_err(dev, "Failed to allocate memory for watchdog device");
	120	+ return -ENOMEM;
	121	+ }
	122	+ platform_set_drvdata(pdev, wdt);
	123	+
	124	+ spin_lock_init(&wdt->lock);
	125	+
	126	+ wdt->base = of_iomap(np, 0);
	127	+ if (!wdt->base) {
	128	+ dev_err(dev, "Failed to remap watchdog regs");
	129	+ return -ENODEV;
	130	+ }
	131	+
	132	+ watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
	133	+ watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
	134	+ watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout);
	135	+ err = watchdog_register_device(&bcm2835_wdt_wdd);
	136	+ if (err) {
	137	+ dev_err(dev, "Failed to register watchdog device");
	138	+ iounmap(wdt->base);
	139	+ return err;
	140	+ }
	141	+
	142	+ dev_info(dev, "Broadcom BCM2835 watchdog timer");
	143	+ return 0;
	144	+}
	145	+
	146	+static int bcm2835_wdt_remove(struct platform_device *pdev)
	147	+{
	148	+ struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
	149	+
	150	+ watchdog_unregister_device(&bcm2835_wdt_wdd);
	151	+ iounmap(wdt->base);
	152	+
	153	+ return 0;
	154	+}
	155	+
	156	+static void bcm2835_wdt_shutdown(struct platform_device *pdev)
	157	+{
	158	+ bcm2835_wdt_stop(&bcm2835_wdt_wdd);
	159	+}
	160	+
	161	+static const struct of_device_id bcm2835_wdt_of_match[] = {
	162	+ { .compatible = "brcm,bcm2835-pm-wdt", },
	163	+ {},
	164	+};
	165	+MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
	166	+
	167	+static struct platform_driver bcm2835_wdt_driver = {
	168	+ .probe = bcm2835_wdt_probe,
	169	+ .remove = bcm2835_wdt_remove,
	170	+ .shutdown = bcm2835_wdt_shutdown,
	171	+ .driver = {
	172	+ .name = "bcm2835-wdt",
	173	+ .owner = THIS_MODULE,
	174	+ .of_match_table = bcm2835_wdt_of_match,
	175	+ },
	176	+};
	177	+module_platform_driver(bcm2835_wdt_driver);
	178	+
	179	+module_param(heartbeat, uint, 0);
	180	+MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
	181	+
	182	+module_param(nowayout, bool, 0);
	183	+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	184	+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	185	+
	186	+MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
	187	+MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer");
	188	+MODULE_LICENSE("GPL");
	189	+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);