Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /********************************************************************* |
| 2 | * |
| 3 | * sir_dongle.c: manager for serial dongle protocol drivers |
| 4 | * |
| 5 | * Copyright (c) 2002 Martin Diehl |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License as |
| 9 | * published by the Free Software Foundation; either version 2 of |
| 10 | * the License, or (at your option) any later version. |
| 11 | * |
| 12 | ********************************************************************/ |
| 13 | |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/kernel.h> |
| 16 | #include <linux/init.h> |
| 17 | #include <linux/smp_lock.h> |
| 18 | #include <linux/kmod.h> |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 19 | #include <linux/mutex.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | |
| 21 | #include <net/irda/irda.h> |
| 22 | |
| 23 | #include "sir-dev.h" |
| 24 | |
| 25 | /************************************************************************** |
| 26 | * |
| 27 | * dongle registration and attachment |
| 28 | * |
| 29 | */ |
| 30 | |
| 31 | static LIST_HEAD(dongle_list); /* list of registered dongle drivers */ |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 32 | static DEFINE_MUTEX(dongle_list_lock); /* protects the list */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | |
| 34 | int irda_register_dongle(struct dongle_driver *new) |
| 35 | { |
| 36 | struct list_head *entry; |
| 37 | struct dongle_driver *drv; |
| 38 | |
| 39 | IRDA_DEBUG(0, "%s : registering dongle \"%s\" (%d).\n", |
| 40 | __FUNCTION__, new->driver_name, new->type); |
| 41 | |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 42 | mutex_lock(&dongle_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | list_for_each(entry, &dongle_list) { |
| 44 | drv = list_entry(entry, struct dongle_driver, dongle_list); |
| 45 | if (new->type == drv->type) { |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 46 | mutex_unlock(&dongle_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | return -EEXIST; |
| 48 | } |
| 49 | } |
| 50 | list_add(&new->dongle_list, &dongle_list); |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 51 | mutex_unlock(&dongle_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 52 | return 0; |
| 53 | } |
Adrian Bunk | 214ad78 | 2006-01-10 13:10:02 -0800 | [diff] [blame] | 54 | EXPORT_SYMBOL(irda_register_dongle); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | |
| 56 | int irda_unregister_dongle(struct dongle_driver *drv) |
| 57 | { |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 58 | mutex_lock(&dongle_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | list_del(&drv->dongle_list); |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 60 | mutex_unlock(&dongle_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | return 0; |
| 62 | } |
Adrian Bunk | 214ad78 | 2006-01-10 13:10:02 -0800 | [diff] [blame] | 63 | EXPORT_SYMBOL(irda_unregister_dongle); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | |
| 65 | int sirdev_get_dongle(struct sir_dev *dev, IRDA_DONGLE type) |
| 66 | { |
| 67 | struct list_head *entry; |
| 68 | const struct dongle_driver *drv = NULL; |
| 69 | int err = -EINVAL; |
| 70 | |
| 71 | #ifdef CONFIG_KMOD |
| 72 | request_module("irda-dongle-%d", type); |
| 73 | #endif |
| 74 | |
| 75 | if (dev->dongle_drv != NULL) |
| 76 | return -EBUSY; |
| 77 | |
| 78 | /* serialize access to the list of registered dongles */ |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 79 | mutex_lock(&dongle_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | |
| 81 | list_for_each(entry, &dongle_list) { |
| 82 | drv = list_entry(entry, struct dongle_driver, dongle_list); |
| 83 | if (drv->type == type) |
| 84 | break; |
| 85 | else |
| 86 | drv = NULL; |
| 87 | } |
| 88 | |
| 89 | if (!drv) { |
| 90 | err = -ENODEV; |
| 91 | goto out_unlock; /* no such dongle */ |
| 92 | } |
| 93 | |
| 94 | /* handling of SMP races with dongle module removal - three cases: |
| 95 | * 1) dongle driver was already unregistered - then we haven't found the |
| 96 | * requested dongle above and are already out here |
| 97 | * 2) the module is already marked deleted but the driver is still |
| 98 | * registered - then the try_module_get() below will fail |
| 99 | * 3) the try_module_get() below succeeds before the module is marked |
| 100 | * deleted - then sys_delete_module() fails and prevents the removal |
| 101 | * because the module is in use. |
| 102 | */ |
| 103 | |
| 104 | if (!try_module_get(drv->owner)) { |
| 105 | err = -ESTALE; |
| 106 | goto out_unlock; /* rmmod already pending */ |
| 107 | } |
| 108 | dev->dongle_drv = drv; |
| 109 | |
| 110 | if (!drv->open || (err=drv->open(dev))!=0) |
| 111 | goto out_reject; /* failed to open driver */ |
| 112 | |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 113 | mutex_unlock(&dongle_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | return 0; |
| 115 | |
| 116 | out_reject: |
| 117 | dev->dongle_drv = NULL; |
| 118 | module_put(drv->owner); |
| 119 | out_unlock: |
Arjan van de Ven | d4ccd08 | 2006-03-20 22:32:53 -0800 | [diff] [blame] | 120 | mutex_unlock(&dongle_list_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | return err; |
| 122 | } |
| 123 | |
| 124 | int sirdev_put_dongle(struct sir_dev *dev) |
| 125 | { |
| 126 | const struct dongle_driver *drv = dev->dongle_drv; |
| 127 | |
| 128 | if (drv) { |
| 129 | if (drv->close) |
| 130 | drv->close(dev); /* close this dongle instance */ |
| 131 | |
| 132 | dev->dongle_drv = NULL; /* unlink the dongle driver */ |
| 133 | module_put(drv->owner);/* decrement driver's module refcount */ |
| 134 | } |
| 135 | |
| 136 | return 0; |
| 137 | } |