forked from luck/tmp_suning_uos_patched
[WATCHDOG] mpc5200_wdt clean-up
* Add MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); * Add mandatory WDIOC_GETSTATUS and WDIOC_GETBOOTSTATUS ioctl's. * If unknown ioctl is used we should return -ENOTTY. * All watchdog device drivers are VFSs (Virtual File Systems). We thus return a nonseekable_open(inode, file) when we open the VFS. * Make sure that /dev/watchdog can be opened by 1 parent * Add spin-locking to prevent that forked children can disturb each other's operations. Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
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@ -3,6 +3,7 @@
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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 <asm/of_platform.h>
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#include <asm/uaccess.h>
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#include <asm/mpc52xx.h>
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@ -19,8 +20,11 @@ struct mpc5200_wdt {
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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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@ -47,24 +51,31 @@ static int mpc5200_wdt_get_timeout(struct mpc5200_wdt *wdt)
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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 | 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 | (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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@ -91,11 +102,17 @@ static int mpc5200_wdt_ioctl(struct inode *inode, struct file *file,
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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, sizeof(mpc5200_wdt_info));
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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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@ -112,15 +129,23 @@ static int mpc5200_wdt_ioctl(struct inode *inode, struct file *file,
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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 0;
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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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@ -129,6 +154,7 @@ static int mpc5200_wdt_release(struct inode *inode, struct file *file)
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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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@ -173,6 +199,7 @@ static int mpc5200_wdt_probe(struct of_device *op, const struct of_device_id *ma
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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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@ -256,3 +283,4 @@ 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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