1 files changed, 326 insertions, 0 deletions
diff --git a/drivers/watchdog/rc32434_wdt.c b/drivers/watchdog/rc32434_wdt.c
new file mode 100644
index 000000000..e74802f3a
--- /dev/null
+++ b/drivers/watchdog/rc32434_wdt.c
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  IDT Interprise 79RC32434 watchdog driver
+ *
+ *  Copyright (C) 2006, Ondrej Zajicek <santiago@crfreenet.org>
+ *  Copyright (C) 2008, Florian Fainelli <florian@openwrt.org>
+ *
+ *  based on
+ *  SoftDog 0.05:	A Software Watchdog Device
+ *
+ *  (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
+ *					All Rights Reserved.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>		/* For module specific items */
+#include <linux/moduleparam.h>		/* For new moduleparam's */
+#include <linux/types.h>		/* For standard types (like size_t) */
+#include <linux/errno.h>		/* For the -ENODEV/... values */
+#include <linux/kernel.h>		/* For printk/panic/... */
+#include <linux/fs.h>			/* For file operations */
+#include <linux/miscdevice.h>		/* For struct miscdevice */
+#include <linux/watchdog.h>		/* For the watchdog specific items */
+#include <linux/init.h>			/* For __init/__exit/... */
+#include <linux/platform_device.h>	/* For platform_driver framework */
+#include <linux/spinlock.h>		/* For spin_lock/spin_unlock/... */
+#include <linux/uaccess.h>		/* For copy_to_user/put_user/... */
+#include <linux/io.h>			/* For devm_ioremap */
+
+#include <asm/mach-rc32434/integ.h>	/* For the Watchdog registers */
+
+#define VERSION "1.0"
+
+static struct {
+	unsigned long inuse;
+	spinlock_t io_lock;
+} rc32434_wdt_device;
+
+static struct integ __iomem *wdt_reg;
+
+static int expect_close;
+
+/* Board internal clock speed in Hz,
+ * the watchdog timer ticks at. */
+extern unsigned int idt_cpu_freq;
+
+/* translate wtcompare value to seconds and vice versa */
+#define WTCOMP2SEC(x)	(x / idt_cpu_freq)
+#define SEC2WTCOMP(x)	(x * idt_cpu_freq)
+
+/* Use a default timeout of 20s. This should be
+ * safe for CPU clock speeds up to 400MHz, as
+ * ((2 ^ 32) - 1) / (400MHz / 2) = 21s.  */
+#define WATCHDOG_TIMEOUT 20
+
+static int timeout = WATCHDOG_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout value, in seconds (default="
+		__MODULE_STRING(WATCHDOG_TIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+/* apply or and nand masks to data read from addr and write back */
+#define SET_BITS(addr, or, nand) \
+	writel((readl(&addr) | or) & ~nand, &addr)
+
+static int rc32434_wdt_set(int new_timeout)
+{
+	int max_to = WTCOMP2SEC((u32)-1);
+
+	if (new_timeout < 0 || new_timeout > max_to) {
+		pr_err("timeout value must be between 0 and %d\n", max_to);
+		return -EINVAL;
+	}
+	timeout = new_timeout;
+	spin_lock(&rc32434_wdt_device.io_lock);
+	writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare);
+	spin_unlock(&rc32434_wdt_device.io_lock);
+
+	return 0;
+}
+
+static void rc32434_wdt_start(void)
+{
+	u32 or, nand;
+
+	spin_lock(&rc32434_wdt_device.io_lock);
+
+	/* zero the counter before enabling */
+	writel(0, &wdt_reg->wtcount);
+
+	/* don't generate a non-maskable interrupt,
+	 * do a warm reset instead */
+	nand = 1 << RC32434_ERR_WNE;
+	or = 1 << RC32434_ERR_WRE;
+
+	/* reset the ERRCS timeout bit in case it's set */
+	nand |= 1 << RC32434_ERR_WTO;
+
+	SET_BITS(wdt_reg->errcs, or, nand);
+
+	/* set the timeout (either default or based on module param) */
+	rc32434_wdt_set(timeout);
+
+	/* reset WTC timeout bit and enable WDT */
+	nand = 1 << RC32434_WTC_TO;
+	or = 1 << RC32434_WTC_EN;
+
+	SET_BITS(wdt_reg->wtc, or, nand);
+
+	spin_unlock(&rc32434_wdt_device.io_lock);
+	pr_info("Started watchdog timer\n");
+}
+
+static void rc32434_wdt_stop(void)
+{
+	spin_lock(&rc32434_wdt_device.io_lock);
+
+	/* Disable WDT */
+	SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN);
+
+	spin_unlock(&rc32434_wdt_device.io_lock);
+	pr_info("Stopped watchdog timer\n");
+}
+
+static void rc32434_wdt_ping(void)
+{
+	spin_lock(&rc32434_wdt_device.io_lock);
+	writel(0, &wdt_reg->wtcount);
+	spin_unlock(&rc32434_wdt_device.io_lock);
+}
+
+static int rc32434_wdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
+		return -EBUSY;
+
+	if (nowayout)
+		__module_get(THIS_MODULE);
+
+	rc32434_wdt_start();
+	rc32434_wdt_ping();
+
+	return stream_open(inode, file);
+}
+
+static int rc32434_wdt_release(struct inode *inode, struct file *file)
+{
+	if (expect_close == 42) {
+		rc32434_wdt_stop();
+		module_put(THIS_MODULE);
+	} else {
+		pr_crit("device closed unexpectedly. WDT will not stop!\n");
+		rc32434_wdt_ping();
+	}
+	clear_bit(0, &rc32434_wdt_device.inuse);
+	return 0;
+}
+
+static ssize_t rc32434_wdt_write(struct file *file, const char *data,
+				size_t len, loff_t *ppos)
+{
+	if (len) {
+		if (!nowayout) {
+			size_t i;
+
+			/* In case it was set long ago */
+			expect_close = 0;
+
+			for (i = 0; i != len; i++) {
+				char c;
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					expect_close = 42;
+			}
+		}
+		rc32434_wdt_ping();
+		return len;
+	}
+	return 0;
+}
+
+static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
+				unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int new_timeout;
+	unsigned int value;
+	static const struct watchdog_info ident = {
+		.options =		WDIOF_SETTIMEOUT |
+					WDIOF_KEEPALIVEPING |
+					WDIOF_MAGICCLOSE,
+		.identity =		"RC32434_WDT Watchdog",
+	};
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		if (copy_to_user(argp, &ident, sizeof(ident)))
+			return -EFAULT;
+		break;
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		value = 0;
+		if (copy_to_user(argp, &value, sizeof(int)))
+			return -EFAULT;
+		break;
+	case WDIOC_SETOPTIONS:
+		if (copy_from_user(&value, argp, sizeof(int)))
+			return -EFAULT;
+		switch (value) {
+		case WDIOS_ENABLECARD:
+			rc32434_wdt_start();
+			break;
+		case WDIOS_DISABLECARD:
+			rc32434_wdt_stop();
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case WDIOC_KEEPALIVE:
+		rc32434_wdt_ping();
+		break;
+	case WDIOC_SETTIMEOUT:
+		if (copy_from_user(&new_timeout, argp, sizeof(int)))
+			return -EFAULT;
+		if (rc32434_wdt_set(new_timeout))
+			return -EINVAL;
+		fallthrough;
+	case WDIOC_GETTIMEOUT:
+		return copy_to_user(argp, &timeout, sizeof(int)) ? -EFAULT : 0;
+	default:
+		return -ENOTTY;
+	}
+
+	return 0;
+}
+
+static const struct file_operations rc32434_wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= rc32434_wdt_write,
+	.unlocked_ioctl	= rc32434_wdt_ioctl,
+	.compat_ioctl	= compat_ptr_ioctl,
+	.open		= rc32434_wdt_open,
+	.release	= rc32434_wdt_release,
+};
+
+static struct miscdevice rc32434_wdt_miscdev = {
+	.minor	= WATCHDOG_MINOR,
+	.name	= "watchdog",
+	.fops	= &rc32434_wdt_fops,
+};
+
+static int rc32434_wdt_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct resource *r;
+
+	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res");
+	if (!r) {
+		pr_err("failed to retrieve resources\n");
+		return -ENODEV;
+	}
+
+	wdt_reg = devm_ioremap(&pdev->dev, r->start, resource_size(r));
+	if (!wdt_reg) {
+		pr_err("failed to remap I/O resources\n");
+		return -ENXIO;
+	}
+
+	spin_lock_init(&rc32434_wdt_device.io_lock);
+
+	/* Make sure the watchdog is not running */
+	rc32434_wdt_stop();
+
+	/* Check that the heartbeat value is within it's range;
+	 * if not reset to the default */
+	if (rc32434_wdt_set(timeout)) {
+		rc32434_wdt_set(WATCHDOG_TIMEOUT);
+		pr_info("timeout value must be between 0 and %d\n",
+			WTCOMP2SEC((u32)-1));
+	}
+
+	ret = misc_register(&rc32434_wdt_miscdev);
+	if (ret < 0) {
+		pr_err("failed to register watchdog device\n");
+		return ret;
+	}
+
+	pr_info("Watchdog Timer version " VERSION ", timer margin: %d sec\n",
+		timeout);
+
+	return 0;
+}
+
+static int rc32434_wdt_remove(struct platform_device *pdev)
+{
+	misc_deregister(&rc32434_wdt_miscdev);
+	return 0;
+}
+
+static void rc32434_wdt_shutdown(struct platform_device *pdev)
+{
+	rc32434_wdt_stop();
+}
+
+static struct platform_driver rc32434_wdt_driver = {
+	.probe		= rc32434_wdt_probe,
+	.remove		= rc32434_wdt_remove,
+	.shutdown	= rc32434_wdt_shutdown,
+	.driver		= {
+			.name = "rc32434_wdt",
+	}
+};
+
+module_platform_driver(rc32434_wdt_driver);
+
+MODULE_AUTHOR("Ondrej Zajicek <santiago@crfreenet.org>,"
+		"Florian Fainelli <florian@openwrt.org>");
+MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
+MODULE_LICENSE("GPL");