1 files changed, 150 insertions, 0 deletions
diff --git a/drivers/w1/w1_family.c b/drivers/w1/w1_family.c
new file mode 100644
index 000000000000..d1d56eca1061
--- /dev/null
+++ b/drivers/w1/w1_family.c
@@ -0,0 +1,150 @@
+/*
+ * 	w1_family.c
+ *
+ * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru>
+ * 
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/spinlock.h>
+#include <linux/list.h>
+#include <linux/delay.h>
+
+#include "w1_family.h"
+
+DEFINE_SPINLOCK(w1_flock);
+static LIST_HEAD(w1_families);
+
+static int w1_check_family(struct w1_family *f)
+{
+	if (!f->fops->rname || !f->fops->rbin || !f->fops->rval || !f->fops->rvalname)
+		return -EINVAL;
+
+	return 0;
+}
+
+int w1_register_family(struct w1_family *newf)
+{
+	struct list_head *ent, *n;
+	struct w1_family *f;
+	int ret = 0;
+
+	if (w1_check_family(newf))
+		return -EINVAL;
+
+	spin_lock(&w1_flock);
+	list_for_each_safe(ent, n, &w1_families) {
+		f = list_entry(ent, struct w1_family, family_entry);
+
+		if (f->fid == newf->fid) {
+			ret = -EEXIST;
+			break;
+		}
+	}
+
+	if (!ret) {
+		atomic_set(&newf->refcnt, 0);
+		newf->need_exit = 0;
+		list_add_tail(&newf->family_entry, &w1_families);
+	}
+
+	spin_unlock(&w1_flock);
+
+	return ret;
+}
+
+void w1_unregister_family(struct w1_family *fent)
+{
+	struct list_head *ent, *n;
+	struct w1_family *f;
+
+	spin_lock(&w1_flock);
+	list_for_each_safe(ent, n, &w1_families) {
+		f = list_entry(ent, struct w1_family, family_entry);
+
+		if (f->fid == fent->fid) {
+			list_del(&fent->family_entry);
+			break;
+		}
+	}
+
+	fent->need_exit = 1;
+
+	spin_unlock(&w1_flock);
+
+	while (atomic_read(&fent->refcnt)) {
+		printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n",
+				fent->fid, atomic_read(&fent->refcnt));
+
+		if (msleep_interruptible(1000))
+			flush_signals(current);
+	}
+}
+
+/*
+ * Should be called under w1_flock held.
+ */
+struct w1_family * w1_family_registered(u8 fid)
+{
+	struct list_head *ent, *n;
+	struct w1_family *f = NULL;
+	int ret = 0;
+
+	list_for_each_safe(ent, n, &w1_families) {
+		f = list_entry(ent, struct w1_family, family_entry);
+
+		if (f->fid == fid) {
+			ret = 1;
+			break;
+		}
+	}
+
+	return (ret) ? f : NULL;
+}
+
+void w1_family_put(struct w1_family *f)
+{
+	spin_lock(&w1_flock);
+	__w1_family_put(f);
+	spin_unlock(&w1_flock);
+}
+
+void __w1_family_put(struct w1_family *f)
+{
+	if (atomic_dec_and_test(&f->refcnt))
+		f->need_exit = 1;
+}
+
+void w1_family_get(struct w1_family *f)
+{
+	spin_lock(&w1_flock);
+	__w1_family_get(f);
+	spin_unlock(&w1_flock);
+
+}
+
+void __w1_family_get(struct w1_family *f)
+{
+	smp_mb__before_atomic_inc();
+	atomic_inc(&f->refcnt);
+	smp_mb__after_atomic_inc();
+}
+
+EXPORT_SYMBOL(w1_family_get);
+EXPORT_SYMBOL(w1_family_put);
+EXPORT_SYMBOL(w1_family_registered);
+EXPORT_SYMBOL(w1_unregister_family);
+EXPORT_SYMBOL(w1_register_family);