[WATCHDOG] ep93xx: implemented watchdog timer driver for TS-72xx SBCs

Technologic Systems TS-72xx SBCs have external glue logic
CPLD which includes watchdog timer. This driver implements
kernel support for that.

Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 516 insertions, 0 deletions

diff --git a/drivers/watchdog/ts72xx_wdt.c b/drivers/watchdog/ts72xx_wdt.c
new file mode 100644
index 000000000000..c4a4d37f85af
--- /dev/null
+++ b/drivers/watchdog/ts72xx_wdt.c
@@ -0,0 +1,516 @@
+/*
+ * Watchdog driver for Technologic Systems TS-72xx based SBCs
+ * (TS-7200, TS-7250 and TS-7260). These boards have external
+ * glue logic CPLD chip, which includes programmable watchdog
+ * timer.
+ *
+ * Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
+ *
+ * This driver is based on ep93xx_wdt and wm831x_wdt drivers.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/fs.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/miscdevice.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/uaccess.h>
+
+#define TS72XX_WDT_FEED_VAL             0x05
+#define TS72XX_WDT_DEFAULT_TIMEOUT      8
+
+static int timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. "
+                          "(1 <= timeout <= 8, default="
+                          __MODULE_STRING(TS72XX_WDT_DEFAULT_TIMEOUT)
+                          ")");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
+
+/**
+ * struct ts72xx_wdt - watchdog control structure
+ * @lock: lock that protects this structure
+ * @regval: watchdog timeout value suitable for control register
+ * @flags: flags controlling watchdog device state
+ * @control_reg: watchdog control register
+ * @feed_reg: watchdog feed register
+ * @pdev: back pointer to platform dev
+ */
+struct ts72xx_wdt {
+        struct mutex    lock;
+        int             regval;
+
+#define TS72XX_WDT_BUSY_FLAG            1
+#define TS72XX_WDT_EXPECT_CLOSE_FLAG    2
+        int             flags;
+
+        void __iomem    *control_reg;
+        void __iomem    *feed_reg;
+
+        struct platform_device *pdev;
+};
+
+struct platform_device *ts72xx_wdt_pdev;
+
+/*
+ * TS-72xx Watchdog supports following timeouts (value written
+ * to control register):
+ *      value   description
+ *      -------------------------
+ *      0x00    watchdog disabled
+ *      0x01    250ms
+ *      0x02    500ms
+ *      0x03    1s
+ *      0x04    reserved
+ *      0x05    2s
+ *      0x06    4s
+ *      0x07    8s
+ *
+ * Timeouts below 1s are not very usable so we don't
+ * allow them at all.
+ *
+ * We provide two functions that convert between these:
+ * timeout_to_regval() and regval_to_timeout().
+ */
+static const struct {
+        int     timeout;
+        int     regval;
+} ts72xx_wdt_map[] = {
+        { 1, 3 },
+        { 2, 5 },
+        { 4, 6 },
+        { 8, 7 },
+};
+
+/**
+ * timeout_to_regval() - converts given timeout to control register value
+ * @new_timeout: timeout in seconds to be converted
+ *
+ * Function converts given @new_timeout into valid value that can
+ * be programmed into watchdog control register. When conversion is
+ * not possible, function returns %-EINVAL.
+ */
+static int timeout_to_regval(int new_timeout)
+{
+        int i;
+
+        /* first limit it to 1 - 8 seconds */
+        new_timeout = clamp_val(new_timeout, 1, 8);
+
+        for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
+                if (ts72xx_wdt_map[i].timeout >= new_timeout)
+                        return ts72xx_wdt_map[i].regval;
+        }
+
+        return -EINVAL;
+}
+
+/**
+ * regval_to_timeout() - converts control register value to timeout
+ * @regval: control register value to be converted
+ *
+ * Function converts given @regval to timeout in seconds (1, 2, 4 or 8).
+ * If @regval cannot be converted, function returns %-EINVAL.
+ */
+static int regval_to_timeout(int regval)
+{
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
+                if (ts72xx_wdt_map[i].regval == regval)
+                        return ts72xx_wdt_map[i].timeout;
+        }
+
+        return -EINVAL;
+}
+
+/**
+ * ts72xx_wdt_kick() - kick the watchdog
+ * @wdt: watchdog to be kicked
+ *
+ * Called with @wdt->lock held.
+ */
+static inline void ts72xx_wdt_kick(struct ts72xx_wdt *wdt)
+{
+        __raw_writeb(TS72XX_WDT_FEED_VAL, wdt->feed_reg);
+}
+
+/**
+ * ts72xx_wdt_start() - starts the watchdog timer
+ * @wdt: watchdog to be started
+ *
+ * This function programs timeout to watchdog timer
+ * and starts it.
+ *
+ * Called with @wdt->lock held.
+ */
+static void ts72xx_wdt_start(struct ts72xx_wdt *wdt)
+{
+        /*
+         * To program the wdt, it first must be "fed" and
+         * only after that (within 30 usecs) the configuration
+         * can be changed.
+         */
+        ts72xx_wdt_kick(wdt);
+        __raw_writeb((u8)wdt->regval, wdt->control_reg);
+}
+
+/**
+ * ts72xx_wdt_stop() - stops the watchdog timer
+ * @wdt: watchdog to be stopped
+ *
+ * Called with @wdt->lock held.
+ */
+static void ts72xx_wdt_stop(struct ts72xx_wdt *wdt)
+{
+        ts72xx_wdt_kick(wdt);
+        __raw_writeb(0, wdt->control_reg);
+}
+
+static int ts72xx_wdt_open(struct inode *inode, struct file *file)
+{
+        struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev);
+        int regval;
+
+        /*
+         * Try to convert default timeout to valid register
+         * value first.
+         */
+        regval = timeout_to_regval(timeout);
+        if (regval < 0) {
+                dev_err(&wdt->pdev->dev,
+                        "failed to convert timeout (%d) to register value\n",
+                        timeout);
+                return -EINVAL;
+        }
+
+        if (mutex_lock_interruptible(&wdt->lock))
+                return -ERESTARTSYS;
+
+        if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) {
+                mutex_unlock(&wdt->lock);
+                return -EBUSY;
+        }
+
+        wdt->flags = TS72XX_WDT_BUSY_FLAG;
+        wdt->regval = regval;
+        file->private_data = wdt;
+
+        ts72xx_wdt_start(wdt);
+
+        mutex_unlock(&wdt->lock);
+        return nonseekable_open(inode, file);
+}
+
+static int ts72xx_wdt_release(struct inode *inode, struct file *file)
+{
+        struct ts72xx_wdt *wdt = file->private_data;
+
+        if (mutex_lock_interruptible(&wdt->lock))
+                return -ERESTARTSYS;
+
+        if ((wdt->flags & TS72XX_WDT_EXPECT_CLOSE_FLAG) != 0) {
+                ts72xx_wdt_stop(wdt);
+        } else {
+                dev_warn(&wdt->pdev->dev,
+                         "TS-72XX WDT device closed unexpectly. "
+                         "Watchdog timer will not stop!\n");
+                /*
+                 * Kick it one more time, to give userland some time
+                 * to recover (for example, respawning the kicker
+                 * daemon).
+                 */
+                ts72xx_wdt_kick(wdt);
+        }
+
+        wdt->flags = 0;
+
+        mutex_unlock(&wdt->lock);
+        return 0;
+}
+
+static ssize_t ts72xx_wdt_write(struct file *file,
+                                const char __user *data,
+                                size_t len,
+                                loff_t *ppos)
+{
+        struct ts72xx_wdt *wdt = file->private_data;
+
+        if (!len)
+                return 0;
+
+        if (mutex_lock_interruptible(&wdt->lock))
+                return -ERESTARTSYS;
+
+        ts72xx_wdt_kick(wdt);
+
+        /*
+         * Support for magic character closing. User process
+         * writes 'V' into the device, just before it is closed.
+         * This means that we know that the wdt timer can be
+         * stopped after user closes the device.
+         */
+        if (!nowayout) {
+                int i;
+
+                for (i = 0; i < len; i++) {
+                        char c;
+
+                        /* In case it was set long ago */
+                        wdt->flags &= ~TS72XX_WDT_EXPECT_CLOSE_FLAG;
+
+                        if (get_user(c, data + i)) {
+                                mutex_unlock(&wdt->lock);
+                                return -EFAULT;
+                        }
+                        if (c == 'V') {
+                                wdt->flags |= TS72XX_WDT_EXPECT_CLOSE_FLAG;
+                                break;
+                        }
+                }
+        }
+
+        mutex_unlock(&wdt->lock);
+        return len;
+}
+
+static const struct watchdog_info winfo = {
+        .options                = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
+                                  WDIOF_MAGICCLOSE,
+        .firmware_version       = 1,
+        .identity               = "TS-72XX WDT",
+};
+
+static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
+                             unsigned long arg)
+{
+        struct ts72xx_wdt *wdt = file->private_data;
+        void __user *argp = (void __user *)arg;
+        int __user *p = (int __user *)argp;
+        int error = 0;
+
+        if (mutex_lock_interruptible(&wdt->lock))
+                return -ERESTARTSYS;
+
+        switch (cmd) {
+        case WDIOC_GETSUPPORT:
+                error = copy_to_user(argp, &winfo, sizeof(winfo));
+                break;
+
+        case WDIOC_KEEPALIVE:
+                ts72xx_wdt_kick(wdt);
+                break;
+
+        case WDIOC_SETOPTIONS: {
+                int options;
+
+                if (get_user(options, p)) {
+                        error = -EFAULT;
+                        break;
+                }
+
+                error = -EINVAL;
+
+                if ((options & WDIOS_DISABLECARD) != 0) {
+                        ts72xx_wdt_stop(wdt);
+                        error = 0;
+                }
+                if ((options & WDIOS_ENABLECARD) != 0) {
+                        ts72xx_wdt_start(wdt);
+                        error = 0;
+                }
+
+                break;
+        }
+
+        case WDIOC_SETTIMEOUT: {
+                int new_timeout;
+
+                if (get_user(new_timeout, p)) {
+                        error = -EFAULT;
+                } else {
+                        int regval;
+
+                        regval = timeout_to_regval(new_timeout);
+                        if (regval < 0) {
+                                error = -EINVAL;
+                        } else {
+                                ts72xx_wdt_stop(wdt);
+                                wdt->regval = regval;
+                                ts72xx_wdt_start(wdt);
+                        }
+                }
+                if (error)
+                        break;
+
+                /*FALLTHROUGH*/
+        }
+
+        case WDIOC_GETTIMEOUT:
+                if (put_user(regval_to_timeout(wdt->regval), p))
+                        error = -EFAULT;
+                break;
+
+        default:
+                error = -ENOTTY;
+                break;
+        }
+
+        mutex_unlock(&wdt->lock);
+        return error;
+}
+
+static const struct file_operations ts72xx_wdt_fops = {
+        .owner          = THIS_MODULE,
+        .llseek         = no_llseek,
+        .open           = ts72xx_wdt_open,
+        .release        = ts72xx_wdt_release,
+        .write          = ts72xx_wdt_write,
+        .unlocked_ioctl = ts72xx_wdt_ioctl,
+};
+
+static struct miscdevice ts72xx_wdt_miscdev = {
+        .minor          = WATCHDOG_MINOR,
+        .name           = "watchdog",
+        .fops           = &ts72xx_wdt_fops,
+};
+
+static __devinit int ts72xx_wdt_probe(struct platform_device *pdev)
+{
+        struct ts72xx_wdt *wdt;
+        struct resource *r1, *r2;
+        int error = 0;
+
+        wdt = kzalloc(sizeof(struct ts72xx_wdt), GFP_KERNEL);
+        if (!wdt) {
+                dev_err(&pdev->dev, "failed to allocate memory\n");
+                return -ENOMEM;
+        }
+
+        r1 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        if (!r1) {
+                dev_err(&pdev->dev, "failed to get memory resource\n");
+                error = -ENODEV;
+                goto fail;
+        }
+
+        r1 = request_mem_region(r1->start, resource_size(r1), pdev->name);
+        if (!r1) {
+                dev_err(&pdev->dev, "cannot request memory region\n");
+                error = -EBUSY;
+                goto fail;
+        }
+
+        wdt->control_reg = ioremap(r1->start, resource_size(r1));
+        if (!wdt->control_reg) {
+                dev_err(&pdev->dev, "failed to map memory\n");
+                error = -ENODEV;
+                goto fail_free_control;
+        }
+
+        r2 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+        if (!r2) {
+                dev_err(&pdev->dev, "failed to get memory resource\n");
+                error = -ENODEV;
+                goto fail_unmap_control;
+        }
+
+        r2 = request_mem_region(r2->start, resource_size(r2), pdev->name);
+        if (!r2) {
+                dev_err(&pdev->dev, "cannot request memory region\n");
+                error = -EBUSY;
+                goto fail_unmap_control;
+        }
+
+        wdt->feed_reg = ioremap(r2->start, resource_size(r2));
+        if (!wdt->feed_reg) {
+                dev_err(&pdev->dev, "failed to map memory\n");
+                error = -ENODEV;
+                goto fail_free_feed;
+        }
+
+        platform_set_drvdata(pdev, wdt);
+        ts72xx_wdt_pdev = pdev;
+        wdt->pdev = pdev;
+        mutex_init(&wdt->lock);
+
+        error = misc_register(&ts72xx_wdt_miscdev);
+        if (error) {
+                dev_err(&pdev->dev, "failed to register miscdev\n");
+                goto fail_unmap_feed;
+        }
+
+        dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
+
+        return 0;
+
+fail_unmap_feed:
+        platform_set_drvdata(pdev, NULL);
+        iounmap(wdt->feed_reg);
+fail_free_feed:
+        release_mem_region(r2->start, resource_size(r2));
+fail_unmap_control:
+        iounmap(wdt->control_reg);
+fail_free_control:
+        release_mem_region(r1->start, resource_size(r1));
+fail:
+        kfree(wdt);
+        return error;
+}
+
+static __devexit int ts72xx_wdt_remove(struct platform_device *pdev)
+{
+        struct ts72xx_wdt *wdt = platform_get_drvdata(pdev);
+        struct resource *res;
+        int error;
+
+        error = misc_deregister(&ts72xx_wdt_miscdev);
+        platform_set_drvdata(pdev, NULL);
+
+        iounmap(wdt->control_reg);
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        release_mem_region(res->start, resource_size(res));
+
+        iounmap(wdt->feed_reg);
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+        release_mem_region(res->start, resource_size(res));
+
+        kfree(wdt);
+        return error;
+}
+
+static struct platform_driver ts72xx_wdt_driver = {
+        .probe          = ts72xx_wdt_probe,
+        .remove         = __devexit_p(ts72xx_wdt_remove),
+        .driver         = {
+                .name   = "ts72xx-wdt",
+                .owner  = THIS_MODULE,
+        },
+};
+
+static __init int ts72xx_wdt_init(void)
+{
+        return platform_driver_register(&ts72xx_wdt_driver);
+}
+module_init(ts72xx_wdt_init);
+
+static __exit void ts72xx_wdt_exit(void)
+{
+        platform_driver_unregister(&ts72xx_wdt_driver);
+}
+module_exit(ts72xx_wdt_exit);
+
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
+MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ts72xx-wdt");