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