[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>
diff --git a/drivers/char/watchdog/mpc5200_wdt.c b/drivers/char/watchdog/mpc5200_wdt.c
new file mode 100644
index 0000000..cc3299c
--- /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");