From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 drivers/net/irda/sir_dongle.c | 133 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 drivers/net/irda/sir_dongle.c

(limited to 'drivers/net/irda/sir_dongle.c')

diff --git a/drivers/net/irda/sir_dongle.c b/drivers/net/irda/sir_dongle.c
new file mode 100644
index 000000000..7436f73ff
--- /dev/null
+++ b/drivers/net/irda/sir_dongle.c
@@ -0,0 +1,133 @@
+/*********************************************************************
+ *
+ *	sir_dongle.c:	manager for serial dongle protocol drivers
+ *
+ *	Copyright (c) 2002 Martin Diehl
+ *
+ *	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.
+ *
+ ********************************************************************/    
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/mutex.h>
+
+#include <net/irda/irda.h>
+
+#include "sir-dev.h"
+
+/**************************************************************************
+ *
+ * dongle registration and attachment
+ *
+ */
+
+static LIST_HEAD(dongle_list);			/* list of registered dongle drivers */
+static DEFINE_MUTEX(dongle_list_lock);		/* protects the list */
+
+int irda_register_dongle(struct dongle_driver *new)
+{
+	struct list_head *entry;
+	struct dongle_driver *drv;
+
+	pr_debug("%s : registering dongle \"%s\" (%d).\n",
+		 __func__, new->driver_name, new->type);
+
+	mutex_lock(&dongle_list_lock);
+	list_for_each(entry, &dongle_list) {
+		drv = list_entry(entry, struct dongle_driver, dongle_list);
+		if (new->type == drv->type) {
+			mutex_unlock(&dongle_list_lock);
+			return -EEXIST;
+		}
+	}
+	list_add(&new->dongle_list, &dongle_list);
+	mutex_unlock(&dongle_list_lock);
+	return 0;
+}
+EXPORT_SYMBOL(irda_register_dongle);
+
+int irda_unregister_dongle(struct dongle_driver *drv)
+{
+	mutex_lock(&dongle_list_lock);
+	list_del(&drv->dongle_list);
+	mutex_unlock(&dongle_list_lock);
+	return 0;
+}
+EXPORT_SYMBOL(irda_unregister_dongle);
+
+int sirdev_get_dongle(struct sir_dev *dev, IRDA_DONGLE type)
+{
+	struct list_head *entry;
+	const struct dongle_driver *drv = NULL;
+	int err = -EINVAL;
+
+	request_module("irda-dongle-%d", type);
+
+	if (dev->dongle_drv != NULL)
+		return -EBUSY;
+	
+	/* serialize access to the list of registered dongles */
+	mutex_lock(&dongle_list_lock);
+
+	list_for_each(entry, &dongle_list) {
+		drv = list_entry(entry, struct dongle_driver, dongle_list);
+		if (drv->type == type)
+			break;
+		else
+			drv = NULL;
+	}
+
+	if (!drv) {
+		err = -ENODEV;
+		goto out_unlock;	/* no such dongle */
+	}
+
+	/* handling of SMP races with dongle module removal - three cases:
+	 * 1) dongle driver was already unregistered - then we haven't found the
+	 *	requested dongle above and are already out here
+	 * 2) the module is already marked deleted but the driver is still
+	 *	registered - then the try_module_get() below will fail
+	 * 3) the try_module_get() below succeeds before the module is marked
+	 *	deleted - then sys_delete_module() fails and prevents the removal
+	 *	because the module is in use.
+	 */
+
+	if (!try_module_get(drv->owner)) {
+		err = -ESTALE;
+		goto out_unlock;	/* rmmod already pending */
+	}
+	dev->dongle_drv = drv;
+
+	if (!drv->open  ||  (err=drv->open(dev))!=0)
+		goto out_reject;		/* failed to open driver */
+
+	mutex_unlock(&dongle_list_lock);
+	return 0;
+
+out_reject:
+	dev->dongle_drv = NULL;
+	module_put(drv->owner);
+out_unlock:
+	mutex_unlock(&dongle_list_lock);
+	return err;
+}
+
+int sirdev_put_dongle(struct sir_dev *dev)
+{
+	const struct dongle_driver *drv = dev->dongle_drv;
+
+	if (drv) {
+		if (drv->close)
+			drv->close(dev);		/* close this dongle instance */
+
+		dev->dongle_drv = NULL;			/* unlink the dongle driver */
+		module_put(drv->owner);/* decrement driver's module refcount */
+	}
+
+	return 0;
+}
-- 
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