[WATCHDOG] mpc5200 watchdog (GPT0)

Driver for internal mpc5200 watchdog on general purpose timer 0.
For IPB clock of 132 MHz the maximum timeout is about 32 seconds.

Signed-off-by: Domen Puncer <domen.puncer@telargo.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 258 insertions, 0 deletions

diff --git a/drivers/char/watchdog/mpc5200_wdt.c b/drivers/char/watchdog/mpc5200_wdt.c
new file mode 100644
index 000000000000..cc3299c03683
--- /dev/null
+++ b/drivers/char/watchdog/mpc5200_wdt.c
@@ -0,0 +1,258 @@
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/io.h>
+#include <asm/of_platform.h>
+#include <asm/uaccess.h>
+#include <asm/mpc52xx.h>
+
+
+#define GPT_MODE_WDT            (1<<15)
+#define GPT_MODE_CE             (1<<12)
+#define GPT_MODE_MS_TIMER       (0x4)
+
+
+struct mpc5200_wdt {
+        unsigned count; /* timer ticks before watchdog kicks in */
+        long ipb_freq;
+        struct miscdevice miscdev;
+        struct resource mem;
+        struct mpc52xx_gpt __iomem *regs;
+};
+
+
+/* misc devices don't provide a way, to get back to 'dev' or 'miscdev' from
+ * file operations, which sucks. But there can be max 1 watchdog anyway, so...
+ */
+static struct mpc5200_wdt *wdt_global;
+
+
+/* helper to calculate timeout in timer counts */
+static void mpc5200_wdt_set_timeout(struct mpc5200_wdt *wdt, int timeout)
+{
+        /* use biggest prescaler of 64k */
+        wdt->count = (wdt->ipb_freq + 0xffff) / 0x10000 * timeout;
+
+        if (wdt->count > 0xffff)
+                wdt->count = 0xffff;
+}
+/* return timeout in seconds (calculated from timer count) */
+static int mpc5200_wdt_get_timeout(struct mpc5200_wdt *wdt)
+{
+        return wdt->count * 0x10000 / wdt->ipb_freq;
+}
+
+
+/* watchdog operations */
+static int mpc5200_wdt_start(struct mpc5200_wdt *wdt)
+{
+        /* disable */
+        out_be32(&wdt->regs->mode, 0);
+        /* set timeout, with maximum prescaler */
+        out_be32(&wdt->regs->count, 0x0 | wdt->count);
+        /* enable watchdog */
+        out_be32(&wdt->regs->mode, GPT_MODE_CE | GPT_MODE_WDT | GPT_MODE_MS_TIMER);
+
+        return 0;
+}
+static int mpc5200_wdt_ping(struct mpc5200_wdt *wdt)
+{
+        /* writing A5 to OCPW resets the watchdog */
+        out_be32(&wdt->regs->mode, 0xA5000000 | (0xffffff & in_be32(&wdt->regs->mode)));
+        return 0;
+}
+static int mpc5200_wdt_stop(struct mpc5200_wdt *wdt)
+{
+        out_be32(&wdt->regs->mode, 0);
+        return 0;
+}
+
+
+/* file operations */
+static ssize_t mpc5200_wdt_write(struct file *file, const char *data,
+                size_t len, loff_t *ppos)
+{
+        struct mpc5200_wdt *wdt = file->private_data;
+        mpc5200_wdt_ping(wdt);
+        return 0;
+}
+static struct watchdog_info mpc5200_wdt_info = {
+        .options        = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+        .identity       = "mpc5200 watchdog on GPT0",
+};
+static int mpc5200_wdt_ioctl(struct inode *inode, struct file *file,
+                unsigned int cmd, unsigned long arg)
+{
+        struct mpc5200_wdt *wdt = file->private_data;
+        int __user *data = (int __user *)arg;
+        int timeout;
+        int ret = 0;
+
+        switch (cmd) {
+        case WDIOC_GETSUPPORT:
+                ret = copy_to_user(data, &mpc5200_wdt_info, sizeof(mpc5200_wdt_info));
+                if (ret)
+                        ret = -EFAULT;
+                break;
+
+        case WDIOC_KEEPALIVE:
+                mpc5200_wdt_ping(wdt);
+                break;
+
+        case WDIOC_SETTIMEOUT:
+                ret = get_user(timeout, data);
+                if (ret)
+                        break;
+                mpc5200_wdt_set_timeout(wdt, timeout);
+                mpc5200_wdt_start(wdt);
+                /* fall through and return the timeout */
+
+        case WDIOC_GETTIMEOUT:
+                timeout = mpc5200_wdt_get_timeout(wdt);
+                ret = put_user(timeout, data);
+                break;
+        }
+        return ret;
+}
+static int mpc5200_wdt_open(struct inode *inode, struct file *file)
+{
+        mpc5200_wdt_set_timeout(wdt_global, 30);
+        mpc5200_wdt_start(wdt_global);
+        file->private_data = wdt_global;
+        return 0;
+}
+static int mpc5200_wdt_release(struct inode *inode, struct file *file)
+{
+#if WATCHDOG_NOWAYOUT == 0
+        struct mpc5200_wdt *wdt = file->private_data;
+        mpc5200_wdt_stop(wdt);
+        wdt->count = 0;         /* == disabled */
+#endif
+        return 0;
+}
+
+static struct file_operations mpc5200_wdt_fops = {
+        .owner  = THIS_MODULE,
+        .write  = mpc5200_wdt_write,
+        .ioctl  = mpc5200_wdt_ioctl,
+        .open   = mpc5200_wdt_open,
+        .release = mpc5200_wdt_release,
+};
+
+/* module operations */
+static int mpc5200_wdt_probe(struct of_device *op, const struct of_device_id *match)
+{
+        struct mpc5200_wdt *wdt;
+        int err;
+        const void *has_wdt;
+        int size;
+
+        has_wdt = of_get_property(op->node, "has-wdt", NULL);
+        if (!has_wdt)
+                return -ENODEV;
+
+        wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
+        if (!wdt)
+                return -ENOMEM;
+
+        wdt->ipb_freq = mpc52xx_find_ipb_freq(op->node);
+
+        err = of_address_to_resource(op->node, 0, &wdt->mem);
+        if (err)
+                goto out_free;
+        size = wdt->mem.end - wdt->mem.start + 1;
+        if (!request_mem_region(wdt->mem.start, size, "mpc5200_wdt")) {
+                err = -ENODEV;
+                goto out_free;
+        }
+        wdt->regs = ioremap(wdt->mem.start, size);
+        if (!wdt->regs) {
+                err = -ENODEV;
+                goto out_release;
+        }
+
+        dev_set_drvdata(&op->dev, wdt);
+
+        wdt->miscdev = (struct miscdevice) {
+                .minor  = WATCHDOG_MINOR,
+                .name   = "watchdog",
+                .fops   = &mpc5200_wdt_fops,
+                .parent = &op->dev,
+        };
+        wdt_global = wdt;
+        err = misc_register(&wdt->miscdev);
+        if (!err)
+                return 0;
+
+        iounmap(wdt->regs);
+ out_release:
+        release_mem_region(wdt->mem.start, size);
+ out_free:
+        kfree(wdt);
+        return err;
+}
+
+static int mpc5200_wdt_remove(struct of_device *op)
+{
+        struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
+
+        mpc5200_wdt_stop(wdt);
+        misc_deregister(&wdt->miscdev);
+        iounmap(wdt->regs);
+        release_mem_region(wdt->mem.start, wdt->mem.end - wdt->mem.start + 1);
+        kfree(wdt);
+
+        return 0;
+}
+static int mpc5200_wdt_suspend(struct of_device *op, pm_message_t state)
+{
+        struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
+        mpc5200_wdt_stop(wdt);
+        return 0;
+}
+static int mpc5200_wdt_resume(struct of_device *op)
+{
+        struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
+        if (wdt->count)
+                mpc5200_wdt_start(wdt);
+        return 0;
+}
+static int mpc5200_wdt_shutdown(struct of_device *op)
+{
+        struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
+        mpc5200_wdt_stop(wdt);
+        return 0;
+}
+
+static struct of_device_id mpc5200_wdt_match[] = {
+        { .compatible = "mpc5200-gpt", },
+        {},
+};
+static struct of_platform_driver mpc5200_wdt_driver = {
+        .owner          = THIS_MODULE,
+        .name           = "mpc5200-gpt-wdt",
+        .match_table    = mpc5200_wdt_match,
+        .probe          = mpc5200_wdt_probe,
+        .remove         = mpc5200_wdt_remove,
+        .suspend        = mpc5200_wdt_suspend,
+        .resume         = mpc5200_wdt_resume,
+        .shutdown       = mpc5200_wdt_shutdown,
+};
+
+
+static int __init mpc5200_wdt_init(void)
+{
+        return of_register_platform_driver(&mpc5200_wdt_driver);
+}
+
+static void __exit mpc5200_wdt_exit(void)
+{
+        of_unregister_platform_driver(&mpc5200_wdt_driver);
+}
+
+module_init(mpc5200_wdt_init);
+module_exit(mpc5200_wdt_exit);
+
+MODULE_AUTHOR("Domen Puncer <domen.puncer@telargo.com>");
+MODULE_LICENSE("Dual BSD/GPL");