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path: root/drivers/net/irda/sir_dongle.c
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Diffstat (limited to 'drivers/net/irda/sir_dongle.c')
-rw-r--r--drivers/net/irda/sir_dongle.c134
1 files changed, 134 insertions, 0 deletions
diff --git a/drivers/net/irda/sir_dongle.c b/drivers/net/irda/sir_dongle.c
new file mode 100644
index 000000000000..c5b76746e72b
--- /dev/null
+++ b/drivers/net/irda/sir_dongle.c
@@ -0,0 +1,134 @@
+/*********************************************************************
+ *
+ * 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/init.h>
+#include <linux/smp_lock.h>
+#include <linux/kmod.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 DECLARE_MUTEX(dongle_list_lock); /* protects the list */
+
+int irda_register_dongle(struct dongle_driver *new)
+{
+ struct list_head *entry;
+ struct dongle_driver *drv;
+
+ IRDA_DEBUG(0, "%s : registering dongle \"%s\" (%d).\n",
+ __FUNCTION__, new->driver_name, new->type);
+
+ down(&dongle_list_lock);
+ list_for_each(entry, &dongle_list) {
+ drv = list_entry(entry, struct dongle_driver, dongle_list);
+ if (new->type == drv->type) {
+ up(&dongle_list_lock);
+ return -EEXIST;
+ }
+ }
+ list_add(&new->dongle_list, &dongle_list);
+ up(&dongle_list_lock);
+ return 0;
+}
+
+int irda_unregister_dongle(struct dongle_driver *drv)
+{
+ down(&dongle_list_lock);
+ list_del(&drv->dongle_list);
+ up(&dongle_list_lock);
+ return 0;
+}
+
+int sirdev_get_dongle(struct sir_dev *dev, IRDA_DONGLE type)
+{
+ struct list_head *entry;
+ const struct dongle_driver *drv = NULL;
+ int err = -EINVAL;
+
+#ifdef CONFIG_KMOD
+ request_module("irda-dongle-%d", type);
+#endif
+
+ if (dev->dongle_drv != NULL)
+ return -EBUSY;
+
+ /* serialize access to the list of registered dongles */
+ down(&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 */
+
+ up(&dongle_list_lock);
+ return 0;
+
+out_reject:
+ dev->dongle_drv = NULL;
+ module_put(drv->owner);
+out_unlock:
+ up(&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;
+}