ARM: sunxi: New watchdog driver for Allwinner A10/A13

This patch adds the driver for the watchdog found in the Allwinner A10 and A13 SoCs. It has DT-support and uses the new watchdog framework.

Signed-off-by Carlo Caione <[email protected]>

---
 drivers/watchdog/Kconfig     |  10 ++
 drivers/watchdog/Makefile    |   1 +
 drivers/watchdog/sunxi_wdt.c | 226 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 237 insertions(+)
 create mode 100644 drivers/watchdog/sunxi_wdt.c

drivers/watchdog/Kconfig +10 -0

index e89fc31..8ad2238 100644
@@ -299,6 +299,16 @@ config ORION_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called orion_wdt.
 
+config SUNXI_WATCHDOG
+	tristate "Allwinner SoCs watchdog support"
+	depends on ARCH_SUNXI
+	select WATCHDOG_CORE
+	help
+	  Say Y here to include support for the watchdog timer
+	  in Allwinner SoCs.
+	  To compile this driver as a module, choose M here: the
+	  module will be called sunxi_wdt.
+
 config COH901327_WATCHDOG
 	bool "ST-Ericsson COH 901 327 watchdog"
 	depends on ARCH_U300

drivers/watchdog/Makefile +1 -0

index a300b94..5012d5f 100644
@@ -47,6 +47,7 @@ obj-$(CONFIG_PNX4008_WATCHDOG) += pnx4008_wdt.o
 obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
 obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
 obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
+obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
 obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
 obj-$(CONFIG_STMP3XXX_RTC_WATCHDOG) += stmp3xxx_rtc_wdt.o
 obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o

drivers/watchdog/sunxi_wdt.c new file +26 -0

new file mode 100644
index 0000000..105b26a
@@ -0,0 +1,226 @@
+/*
+ *      sunxi Watchdog Driver
+ *
+ *      Copyright (c) 2013 Carlo Caione
+ *                    2012 Henrik Nordstrom
+ *
+ *      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.
+ *
+ *      Based on xen_wdt.c
+ *      (c) Copyright 2010 Novell, Inc.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>

drivers/watchdog/sunxi_wdt.c new file +21 -0

+#define WDT_MODE                0x04
+#define WDT_MODE_EN             (1 << 0)
+#define WDT_MODE_RST_EN         (1 << 1)
+
+#define DRV_NAME		"sunxi-wdt"
+#define DRV_VERSION		"1.0"
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static int heartbeat = WDT_MAX_TIMEOUT;
+
+/*
+ * wdt_timeout_map maps the watchdog timer interval value in seconds to
+ * the value of the register WDT_MODE bit 3:6
+ *
+ * [timeout seconds] = register value
+ *
+ */
+
+static const int wdt_timeout_map[] = {
+	[1] = 0b0001,  /* 1s  */
+	[2] = 0b0010,  /* 2s  */

drivers/watchdog/sunxi_wdt.c new file +158 -0

+
+static int sunxi_wdt_ping(struct watchdog_device *sunxi_wdt_dev)
+{
+	u32 reg;
+	void __iomem *wdt_base = watchdog_get_drvdata(sunxi_wdt_dev);
+
+	reg = ioread32(wdt_base + WDT_CTRL);
+	reg |= (WDT_CTRL_RESTART | WDT_CTRL_RESERVED);
+	iowrite32(reg, wdt_base + WDT_CTRL);
+
+	return 0;
+}
+
+static int sunxi_wdt_set_timeout(struct watchdog_device *sunxi_wdt_dev,
+		unsigned int timeout)
+{
+	u32 reg;
+	void __iomem *wdt_base = watchdog_get_drvdata(sunxi_wdt_dev);
+
+	if ((timeout > WDT_MAX_TIMEOUT) || (0 == wdt_timeout_map[timeout]))
+		return -EINVAL;
+
+	sunxi_wdt_dev->timeout = timeout;
+
+	reg = ioread32(wdt_base + WDT_MODE);
+	reg &= ~(WDT_TIMEOUT_MASK);
+	reg |= WDT_MODE_TIMEOUT(wdt_timeout_map[sunxi_wdt_dev->timeout]);
+	iowrite32(reg, wdt_base + WDT_MODE);
+
+	sunxi_wdt_ping(sunxi_wdt_dev);
+
+	return 0;
+}
+
+static int sunxi_wdt_stop(struct watchdog_device *sunxi_wdt_dev)
+{
+	u32 reg;
+	void __iomem *wdt_base = watchdog_get_drvdata(sunxi_wdt_dev);
+
+	reg = ioread32(wdt_base + WDT_MODE);
+	reg &= ~(WDT_MODE_RST_EN | WDT_MODE_EN);
+	iowrite32(reg, wdt_base + WDT_MODE);
+
+	return 0;
+}
+
+static int sunxi_wdt_start(struct watchdog_device *sunxi_wdt_dev)
+{
+	u32 reg;
+	int ret;
+	void __iomem *wdt_base = watchdog_get_drvdata(sunxi_wdt_dev);
+
+	ret = sunxi_wdt_set_timeout(sunxi_wdt_dev, sunxi_wdt_dev->timeout);
+	if (ret < 0)
+		return ret;
+
+	reg = ioread32(wdt_base + WDT_MODE);
+	reg |= (WDT_MODE_RST_EN | WDT_MODE_EN);
+	iowrite32(reg, wdt_base + WDT_MODE);
+
+	return 0;
+}
+
+static const struct watchdog_info sunxi_wdt_info = {
+	.identity	= DRV_NAME,
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_KEEPALIVEPING |
+			  WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops sunxi_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= sunxi_wdt_start,
+	.stop		= sunxi_wdt_stop,
+	.ping		= sunxi_wdt_ping,
+	.set_timeout	= sunxi_wdt_set_timeout,
+};
+
+static struct watchdog_device sunxi_wdt_dev = {
+	.info		= &sunxi_wdt_info,
+	.ops		= &sunxi_wdt_ops,
+	.timeout	= WDT_MAX_TIMEOUT,
+	.max_timeout	= WDT_MAX_TIMEOUT,
+	.min_timeout	= WDT_MIN_TIMEOUT,
+};
+
+static int __init sunxi_wdt_probe(struct platform_device *pdev)
+{
+	int err;
+	void __iomem *wdt_base;
+
+	wdt_base = of_iomap(pdev->dev.of_node, 0);
+	if (unlikely(!wdt_base)) {
+		err = -ENOMEM;
+		goto error_mem_out;
+	}
+
+	sunxi_wdt_dev.parent = &pdev->dev;
+	watchdog_init_timeout(&sunxi_wdt_dev, heartbeat, &pdev->dev);
+	watchdog_set_nowayout(&sunxi_wdt_dev, nowayout);
+
+	err = watchdog_register_device(&sunxi_wdt_dev);
+	if (unlikely(err))
+		goto error_wdt;
+
+	watchdog_set_drvdata(&sunxi_wdt_dev, wdt_base);
+
+	pr_info("Watchdog enabled (heartbeat=%d sec, nowayout=%d)",
+			sunxi_wdt_dev.timeout, nowayout);
+	return 0;
+
+error_wdt:
+	iounmap(wdt_base);
+error_mem_out:
+	return err;
+}
+
+static int __exit sunxi_wdt_remove(struct platform_device *pdev)
+{
+	void __iomem *wdt_base = watchdog_get_drvdata(&sunxi_wdt_dev);
+
+	sunxi_wdt_stop(&sunxi_wdt_dev);
+	watchdog_unregister_device(&sunxi_wdt_dev);
+	iounmap(wdt_base);
+
+	return 0;
+}
+
+static const struct of_device_id sunxi_wdt_dt_ids[] = {
+	{ .compatible = "allwinner,sun4i-wdt" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
+
+static struct platform_driver sunxi_wdt_driver = {
+	.probe		= sunxi_wdt_probe,
+	.remove		= sunxi_wdt_remove,
+	.driver		= {
+		.owner		= THIS_MODULE,
+		.name		= DRV_NAME,
+		.of_match_table	= of_match_ptr(sunxi_wdt_dt_ids)
+	},
+};
+
+module_platform_driver(sunxi_wdt_driver);
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "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_LICENSE("GPL");
+MODULE_AUTHOR("Carlo Caione <[email protected]>");
+MODULE_AUTHOR("Henrik Nordstrom <[email protected]>");
+MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
+MODULE_VERSION(DRV_VERSION);

Signature · 1 line

1.8.2.3

Hi Carlo,

drivers/watchdog/sunxi_wdt.c line 36

Quoted 4 lines

drivers/watchdog/sunxi_wdt.c new file +4 -0

+
+#define WDT_CTRL                0x00
+#define WDT_CTRL_RESTART        (1 << 0)
+#define WDT_CTRL_RESERVED       (0x0a57 << 1)

You didn't replied to me on that part in the previous mail. It doesn't seem to be needed, so why keeping it?

Quoted 1 line · Maxime Ripard

Hi Carlo,

Hi Maxime,

Quoted 7 lines

drivers/watchdog/sunxi_wdt.c line 36

Quoted 4 lines

drivers/watchdog/sunxi_wdt.c new file +4 -0

+
+#define WDT_CTRL                0x00
+#define WDT_CTRL_RESTART        (1 << 0)
+#define WDT_CTRL_RESERVED       (0x0a57 << 1)

You didn't replied to me on that part in the previous mail. It doesn't seem to be needed, so why keeping it?

Actually I wrote you about this on irc (probably you were afk)
Anyway I tested the driver without using the 0x0a57 and without these bits the watchdog is never successfully kicked. I'm going to submit a v3 soon, addressing also the suggestions given by Henrik on linux-sunxi ml.