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path: root/drivers/pps/pps.c
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Diffstat (limited to 'drivers/pps/pps.c')
-rw-r--r--drivers/pps/pps.c50
1 files changed, 49 insertions, 1 deletions
diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
index 9f7c2e858dd..79b44557813 100644
--- a/drivers/pps/pps.c
+++ b/drivers/pps/pps.c
@@ -30,6 +30,7 @@
#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/pps_kernel.h>
+#include <linux/slab.h>
/*
* Local variables
@@ -38,6 +39,9 @@
static dev_t pps_devt;
static struct class *pps_class;
+static DEFINE_SPINLOCK(pps_idr_lock);
+static DEFINE_IDR(pps_idr);
+
/*
* Char device methods
*/
@@ -229,11 +233,48 @@ static const struct file_operations pps_cdev_fops = {
.release = pps_cdev_release,
};
+static void pps_device_destruct(struct device *dev)
+{
+ struct pps_device *pps = dev_get_drvdata(dev);
+
+ /* release id here to protect others from using it while it's
+ * still in use */
+ spin_lock_irq(&pps_idr_lock);
+ idr_remove(&pps_idr, pps->id);
+ spin_unlock_irq(&pps_idr_lock);
+
+ kfree(dev);
+ kfree(pps);
+}
+
int pps_register_cdev(struct pps_device *pps)
{
int err;
dev_t devt;
+ /* Get new ID for the new PPS source */
+ if (idr_pre_get(&pps_idr, GFP_KERNEL) == 0)
+ return -ENOMEM;
+
+ /* Now really allocate the PPS source.
+ * After idr_get_new() calling the new source will be freely available
+ * into the kernel.
+ */
+ spin_lock_irq(&pps_idr_lock);
+ err = idr_get_new(&pps_idr, pps, &pps->id);
+ spin_unlock_irq(&pps_idr_lock);
+
+ if (err < 0)
+ return err;
+
+ pps->id &= MAX_ID_MASK;
+ if (pps->id >= PPS_MAX_SOURCES) {
+ pr_err("%s: too many PPS sources in the system\n",
+ pps->info.name);
+ err = -EBUSY;
+ goto free_idr;
+ }
+
devt = MKDEV(MAJOR(pps_devt), pps->id);
cdev_init(&pps->cdev, &pps_cdev_fops);
@@ -243,13 +284,15 @@ int pps_register_cdev(struct pps_device *pps)
if (err) {
pr_err("%s: failed to add char device %d:%d\n",
pps->info.name, MAJOR(pps_devt), pps->id);
- return err;
+ goto free_idr;
}
pps->dev = device_create(pps_class, pps->info.dev, devt, pps,
"pps%d", pps->id);
if (IS_ERR(pps->dev))
goto del_cdev;
+ pps->dev->release = pps_device_destruct;
+
pr_debug("source %s got cdev (%d:%d)\n", pps->info.name,
MAJOR(pps_devt), pps->id);
@@ -258,6 +301,11 @@ int pps_register_cdev(struct pps_device *pps)
del_cdev:
cdev_del(&pps->cdev);
+free_idr:
+ spin_lock_irq(&pps_idr_lock);
+ idr_remove(&pps_idr, pps->id);
+ spin_unlock_irq(&pps_idr_lock);
+
return err;
}