Fixed MTP to work with TWRP

drivers/connector/cn_queue.c

@@ -0,0 +1,161 @@
+/*
+ *	cn_queue.c
+ *
+ * 2004+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
+ * All rights reserved.
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/list.h>
+#include <linux/workqueue.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+#include <linux/suspend.h>
+#include <linux/connector.h>
+#include <linux/delay.h>
+
+static struct cn_callback_entry *
+cn_queue_alloc_callback_entry(struct cn_queue_dev *dev, const char *name,
+			      struct cb_id *id,
+			      void (*callback)(struct cn_msg *,
+					       struct netlink_skb_parms *))
+{
+	struct cn_callback_entry *cbq;
+
+	cbq = kzalloc(sizeof(*cbq), GFP_KERNEL);
+	if (!cbq) {
+		pr_err("Failed to create new callback queue.\n");
+		return NULL;
+	}
+
+	atomic_set(&cbq->refcnt, 1);
+
+	atomic_inc(&dev->refcnt);
+	cbq->pdev = dev;
+
+	snprintf(cbq->id.name, sizeof(cbq->id.name), "%s", name);
+	memcpy(&cbq->id.id, id, sizeof(struct cb_id));
+	cbq->callback = callback;
+	return cbq;
+}
+
+void cn_queue_release_callback(struct cn_callback_entry *cbq)
+{
+	if (!atomic_dec_and_test(&cbq->refcnt))
+		return;
+
+	atomic_dec(&cbq->pdev->refcnt);
+	kfree(cbq);
+}
+
+int cn_cb_equal(struct cb_id *i1, struct cb_id *i2)
+{
+	return ((i1->idx == i2->idx) && (i1->val == i2->val));
+}
+
+int cn_queue_add_callback(struct cn_queue_dev *dev, const char *name,
+			  struct cb_id *id,
+			  void (*callback)(struct cn_msg *,
+					   struct netlink_skb_parms *))
+{
+	struct cn_callback_entry *cbq, *__cbq;
+	int found = 0;
+
+	cbq = cn_queue_alloc_callback_entry(dev, name, id, callback);
+	if (!cbq)
+		return -ENOMEM;
+
+	spin_lock_bh(&dev->queue_lock);
+	list_for_each_entry(__cbq, &dev->queue_list, callback_entry) {
+		if (cn_cb_equal(&__cbq->id.id, id)) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found)
+		list_add_tail(&cbq->callback_entry, &dev->queue_list);
+	spin_unlock_bh(&dev->queue_lock);
+
+	if (found) {
+		cn_queue_release_callback(cbq);
+		return -EINVAL;
+	}
+
+	cbq->seq = 0;
+	cbq->group = cbq->id.id.idx;
+
+	return 0;
+}
+
+void cn_queue_del_callback(struct cn_queue_dev *dev, struct cb_id *id)
+{
+	struct cn_callback_entry *cbq, *n;
+	int found = 0;
+
+	spin_lock_bh(&dev->queue_lock);
+	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry) {
+		if (cn_cb_equal(&cbq->id.id, id)) {
+			list_del(&cbq->callback_entry);
+			found = 1;
+			break;
+		}
+	}
+	spin_unlock_bh(&dev->queue_lock);
+
+	if (found)
+		cn_queue_release_callback(cbq);
+}
+
+struct cn_queue_dev *cn_queue_alloc_dev(const char *name, struct sock *nls)
+{
+	struct cn_queue_dev *dev;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return NULL;
+
+	snprintf(dev->name, sizeof(dev->name), "%s", name);
+	atomic_set(&dev->refcnt, 0);
+	INIT_LIST_HEAD(&dev->queue_list);
+	spin_lock_init(&dev->queue_lock);
+
+	dev->nls = nls;
+
+	return dev;
+}
+
+void cn_queue_free_dev(struct cn_queue_dev *dev)
+{
+	struct cn_callback_entry *cbq, *n;
+
+	spin_lock_bh(&dev->queue_lock);
+	list_for_each_entry_safe(cbq, n, &dev->queue_list, callback_entry)
+		list_del(&cbq->callback_entry);
+	spin_unlock_bh(&dev->queue_lock);
+
+	while (atomic_read(&dev->refcnt)) {
+		pr_info("Waiting for %s to become free: refcnt=%d.\n",
+		       dev->name, atomic_read(&dev->refcnt));
+		msleep(1000);
+	}
+
+	kfree(dev);
+	dev = NULL;
+}