drivers: watchdog: Add ux500-watchdog driver

This driver kicks a watchdog that is located in the
prcmu firmware.

ST-Ericsson Linux next: Not tested, ask SSM for ER
ST-Ericsson ID: 339924
ST-Ericsson FOSS-OUT ID: Trivial

Change-Id: I5fcabc0a409f18914129f6a5c8e17f4267974c61
Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/25029
Reviewed-by: QATEST
Reviewed-by: Linus WALLEIJ <linus.walleij@stericsson.com>

3 files changed, 427 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 21d816e9dfa..c49cfb346bc 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -270,6 +270,22 @@ config COH901327_WATCHDOG
 	  This watchdog is used to reset the system and thus cannot be
 	  compiled as a module.
 
+config UX500_WATCHDOG
+	bool "ST-Ericsson UX500 watchdog"
+	depends on ARCH_U8500
+	default y if MACH_U8500
+	help
+	  Say Y here to include Watchdog timer support for the
+	  watchdog existing in the prcmu of ST-Ericsson UX500 series platforms.
+	  This watchdog is used to reset the system and thus cannot be
+	  compiled as a module.
+
+config UX500_WATCHDOG_DEBUG
+	bool "ST-Ericsson UX500 watchdog DEBUG"
+	depends on ARCH_U8500 && DEBUG_FS
+	help
+	  Say Y here to add various debugfs entries in wdog/
+
 config TWL4030_WATCHDOG
 	tristate "TWL4030 Watchdog"
 	depends on TWL4030_CORE
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index ed26f7094e4..be5bfd49658 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
 obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
 obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
 obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
+obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
 obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
 obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
 obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
diff --git a/drivers/watchdog/ux500_wdt.c b/drivers/watchdog/ux500_wdt.c
new file mode 100644
index 00000000000..fd343197681
--- /dev/null
+++ b/drivers/watchdog/ux500_wdt.c
@@ -0,0 +1,410 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ *
+ * License Terms: GNU General Public License v2
+ *
+ * Author: Jonas Aaberg <jonas.aberg@stericsson.com> for ST-Ericsson
+ *
+ * Heavily based upon geodewdt.c
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+#include <linux/uaccess.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+
+#include <mach/prcmu.h>
+
+#define WATCHDOG_TIMEOUT 600 /* 10 minutes */
+
+#define WDT_FLAGS_OPEN 1
+#define WDT_FLAGS_ORPHAN 2
+
+static unsigned long wdt_flags;
+
+static int timeout = WATCHDOG_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout,
+	"Watchdog timeout in seconds. 1<= timeout <=131, default="
+				__MODULE_STRING(WATCHDOG_TIMEOUT) ".");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout,
+	"Watchdog cannot be stopped once started (default="
+				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+static u8 wdog_id;
+static bool wdt_en;
+static bool wdt_auto_off = true;
+static bool safe_close;
+
+static int ux500_wdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags))
+		return -EBUSY;
+
+	if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags))
+		__module_get(THIS_MODULE);
+
+	prcmu_enable_a9wdog(wdog_id);
+	wdt_en = true;
+
+	return nonseekable_open(inode, file);
+}
+
+static int ux500_wdt_release(struct inode *inode, struct file *file)
+{
+	if (safe_close) {
+		prcmu_disable_a9wdog(wdog_id);
+		module_put(THIS_MODULE);
+	} else {
+		pr_crit("Unexpected close - watchdog is not stopping.\n");
+		prcmu_kick_a9wdog(wdog_id);
+
+		set_bit(WDT_FLAGS_ORPHAN, &wdt_flags);
+	}
+
+	clear_bit(WDT_FLAGS_OPEN, &wdt_flags);
+	safe_close = false;
+	return 0;
+}
+
+static ssize_t ux500_wdt_write(struct file *file, const char __user *data,
+			       size_t len, loff_t *ppos)
+{
+	if (!len)
+		return len;
+
+	if (!nowayout) {
+		size_t i;
+		safe_close = false;
+
+		for (i = 0; i != len; i++) {
+			char c;
+
+			if (get_user(c, data + i))
+				return -EFAULT;
+
+			if (c == 'V')
+				safe_close = true;
+		}
+	}
+
+	prcmu_kick_a9wdog(wdog_id);
+
+	return len;
+}
+
+static long ux500_wdt_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	int interval;
+
+	static const struct watchdog_info ident = {
+		.options =	WDIOF_SETTIMEOUT |
+				WDIOF_KEEPALIVEPING |
+				WDIOF_MAGICCLOSE,
+		.firmware_version =     1,
+		.identity	= "UX500 WDT",
+	};
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user(argp, &ident,
+				    sizeof(ident)) ? -EFAULT : 0;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+
+	case WDIOC_SETOPTIONS:
+	{
+		int options;
+		int ret = -EINVAL;
+
+		if (get_user(options, p))
+			return -EFAULT;
+
+		if (options & WDIOS_DISABLECARD) {
+			prcmu_disable_a9wdog(wdog_id);
+			wdt_en = false;
+			ret = 0;
+		}
+
+		if (options & WDIOS_ENABLECARD) {
+			prcmu_enable_a9wdog(wdog_id);
+			wdt_en = true;
+			ret = 0;
+		}
+
+		return ret;
+	}
+	case WDIOC_KEEPALIVE:
+		return prcmu_kick_a9wdog(wdog_id);
+
+	case WDIOC_SETTIMEOUT:
+		if (get_user(interval, p))
+			return -EFAULT;
+
+		/* 28 bit resolution in ms, becomes 268435455 ms */
+		if (interval > 26843 || interval < 0)
+			return -EINVAL;
+		timeout = interval;
+		prcmu_disable_a9wdog(wdog_id);
+		prcmu_load_a9wdog(wdog_id, timeout * 1000);
+		prcmu_enable_a9wdog(wdog_id);
+
+	/* Fall through */
+	case WDIOC_GETTIMEOUT:
+		return put_user(timeout, p);
+
+	default:
+		return -ENOTTY;
+	}
+
+	return 0;
+}
+
+static const struct file_operations ux500_wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= ux500_wdt_write,
+	.unlocked_ioctl = ux500_wdt_ioctl,
+	.open		= ux500_wdt_open,
+	.release	= ux500_wdt_release,
+};
+
+static struct miscdevice ux500_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name = "watchdog",
+	.fops = &ux500_wdt_fops,
+};
+
+#ifdef CONFIG_UX500_WATCHDOG_DEBUG
+
+enum wdog_dbg {
+	WDOG_DBG_CONFIG,
+	WDOG_DBG_LOAD,
+	WDOG_DBG_KICK,
+	WDOG_DBG_EN,
+	WDOG_DBG_DIS,
+};
+
+static ssize_t wdog_dbg_write(struct file *file,
+			      const char __user *user_buf,
+			      size_t count, loff_t *ppos)
+{
+	unsigned long val;
+	int err;
+	enum wdog_dbg v = (enum wdog_dbg)((struct seq_file *)
+					  (file->private_data))->private;
+
+	switch(v) {
+	case WDOG_DBG_CONFIG:
+		err = kstrtoul_from_user(user_buf, count, 0, &val);
+
+		if (!err) {
+			wdt_auto_off = val != 0;
+			(void) prcmu_config_a9wdog(1,
+						 wdt_auto_off);
+		}
+		else {
+			pr_err("ux500_wdt:dbg: unknown value\n");
+		}
+		break;
+	case WDOG_DBG_LOAD:
+		err = kstrtoul_from_user(user_buf, count, 0, &val);
+
+		if (!err) {
+			timeout = val;
+			/* Convert seconds to ms */
+			prcmu_disable_a9wdog(wdog_id);
+			prcmu_load_a9wdog(wdog_id, timeout * 1000);
+			prcmu_enable_a9wdog(wdog_id);
+		}
+		else {
+			pr_err("ux500_wdt:dbg: unknown value\n");
+		}
+		break;
+	case WDOG_DBG_KICK:
+		(void) prcmu_kick_a9wdog(wdog_id);
+		break;
+	case WDOG_DBG_EN:
+		wdt_en = true;
+		(void) prcmu_enable_a9wdog(wdog_id);
+		break;
+	case WDOG_DBG_DIS:
+		wdt_en = false;
+		(void) prcmu_disable_a9wdog(wdog_id);
+		break;
+	}
+
+	return count;
+}
+
+static int wdog_dbg_read(struct seq_file *s, void *p)
+{
+	enum wdog_dbg v = (enum wdog_dbg)s->private;
+
+	switch(v) {
+	case WDOG_DBG_CONFIG:
+		seq_printf(s,"wdog is on id %d, auto off on sleep: %s\n",
+			   (int)wdog_id,
+			   wdt_auto_off ? "enabled": "disabled");
+		break;
+	case WDOG_DBG_LOAD:
+		/* In 1s */
+		seq_printf(s, "wdog load is: %d s\n",
+			   timeout);
+		break;
+	case WDOG_DBG_KICK:
+		break;
+	case WDOG_DBG_EN:
+	case WDOG_DBG_DIS:
+		seq_printf(s, "wdog is %sabled.\n",
+			       wdt_en ? "en" : "dis");
+		break;
+	}
+	return 0;
+}
+
+static int wdog_dbg_open(struct inode *inode,
+			struct file *file)
+{
+	return single_open(file, wdog_dbg_read, inode->i_private);
+}
+
+static const struct file_operations wdog_dbg_fops = {
+	.open		= wdog_dbg_open,
+	.write		= wdog_dbg_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.owner		= THIS_MODULE,
+};
+
+static int __init wdog_dbg_init(void)
+{
+	struct dentry *wdog_dir;
+
+	wdog_dir = debugfs_create_dir("wdog", NULL);
+	if (IS_ERR_OR_NULL(wdog_dir))
+		goto fail;
+
+	if (IS_ERR_OR_NULL(debugfs_create_u8("id",
+					     S_IWUGO | S_IRUGO, wdog_dir,
+					     &wdog_id)))
+		goto fail;
+
+	if (IS_ERR_OR_NULL(debugfs_create_file("config",
+					       S_IWUGO | S_IRUGO, wdog_dir,
+					       (void *)WDOG_DBG_CONFIG,
+					       &wdog_dbg_fops)))
+		goto fail;
+
+	if (IS_ERR_OR_NULL(debugfs_create_file("load",
+					       S_IWUGO | S_IRUGO, wdog_dir,
+					       (void *)WDOG_DBG_LOAD,
+					       &wdog_dbg_fops)))
+		goto fail;
+
+	if (IS_ERR_OR_NULL(debugfs_create_file("kick",
+					       S_IWUGO, wdog_dir,
+					       (void *)WDOG_DBG_KICK,
+					       &wdog_dbg_fops)))
+		goto fail;
+
+	if (IS_ERR_OR_NULL(debugfs_create_file("enable",
+					       S_IWUGO | S_IRUGO, wdog_dir,
+					       (void *)WDOG_DBG_EN,
+					       &wdog_dbg_fops)))
+		goto fail;
+
+	if (IS_ERR_OR_NULL(debugfs_create_file("disable",
+					       S_IWUGO | S_IRUGO, wdog_dir,
+					       (void *)WDOG_DBG_DIS,
+					       &wdog_dbg_fops)))
+		goto fail;
+
+	return 0;
+fail:
+	pr_err("ux500:wdog: Failed to initialize wdog dbg.\n");
+	debugfs_remove_recursive(wdog_dir);
+
+	return -EFAULT;
+}
+
+#else
+static inline int __init wdog_dbg_init(void)
+{
+	return 0;
+}
+#endif
+
+static int __init ux500_wdt_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	/* Number of watch dogs */
+	prcmu_config_a9wdog(1, wdt_auto_off);
+	/* convert to ms */
+	prcmu_load_a9wdog(wdog_id, timeout * 1000);
+
+	ret = misc_register(&ux500_wdt_miscdev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to register misc.\n");
+		return ret;
+	}
+
+	ret = wdog_dbg_init();
+	if (ret < 0)
+		goto fail;
+
+	dev_info(&pdev->dev, "initialized.\n");
+
+	return 0;
+fail:
+	misc_deregister(&ux500_wdt_miscdev);
+	return ret;
+}
+
+static int __exit ux500_wdt_remove(struct platform_device *dev)
+{
+	prcmu_disable_a9wdog(wdog_id);
+	wdt_en = false;
+	misc_deregister(&ux500_wdt_miscdev);
+	return 0;
+}
+
+static struct platform_driver ux500_wdt_driver = {
+	.remove		= __exit_p(ux500_wdt_remove),
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= "ux500_wdt",
+	},
+};
+
+static int __init ux500_wdt_init(void)
+{
+	return platform_driver_probe(&ux500_wdt_driver, ux500_wdt_probe);
+}
+
+static void __exit ux500_wdt_exit(void)
+{
+	platform_driver_unregister(&ux500_wdt_driver);
+}
+
+module_init(ux500_wdt_init);
+module_exit(ux500_wdt_exit);
+
+MODULE_AUTHOR("Jonas Aaberg <jonas.aberg@stericsson.com>");
+MODULE_DESCRIPTION("UX500 Watchdog Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);