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1da177e4 LT |
1 | /* |
2 | * transport_class.c - implementation of generic transport classes | |
3 | * using attribute_containers | |
4 | * | |
5 | * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com> | |
6 | * | |
7 | * This file is licensed under GPLv2 | |
8 | * | |
9 | * The basic idea here is to allow any "device controller" (which | |
ebd8bb76 | 10 | * would most often be a Host Bus Adapter to use the services of one |
1da177e4 LT |
11 | * or more tranport classes for performing transport specific |
12 | * services. Transport specific services are things that the generic | |
13 | * command layer doesn't want to know about (speed settings, line | |
14 | * condidtioning, etc), but which the user might be interested in. | |
15 | * Thus, the HBA's use the routines exported by the transport classes | |
16 | * to perform these functions. The transport classes export certain | |
17 | * values to the user via sysfs using attribute containers. | |
18 | * | |
19 | * Note: because not every HBA will care about every transport | |
20 | * attribute, there's a many to one relationship that goes like this: | |
21 | * | |
22 | * transport class<-----attribute container<----class device | |
23 | * | |
24 | * Usually the attribute container is per-HBA, but the design doesn't | |
25 | * mandate that. Although most of the services will be specific to | |
26 | * the actual external storage connection used by the HBA, the generic | |
27 | * transport class is framed entirely in terms of generic devices to | |
28 | * allow it to be used by any physical HBA in the system. | |
29 | */ | |
30 | #include <linux/attribute_container.h> | |
31 | #include <linux/transport_class.h> | |
32 | ||
33 | /** | |
34 | * transport_class_register - register an initial transport class | |
35 | * | |
36 | * @tclass: a pointer to the transport class structure to be initialised | |
37 | * | |
38 | * The transport class contains an embedded class which is used to | |
39 | * identify it. The caller should initialise this structure with | |
40 | * zeros and then generic class must have been initialised with the | |
41 | * actual transport class unique name. There's a macro | |
42 | * DECLARE_TRANSPORT_CLASS() to do this (declared classes still must | |
43 | * be registered). | |
44 | * | |
45 | * Returns 0 on success or error on failure. | |
46 | */ | |
47 | int transport_class_register(struct transport_class *tclass) | |
48 | { | |
49 | return class_register(&tclass->class); | |
50 | } | |
51 | EXPORT_SYMBOL_GPL(transport_class_register); | |
52 | ||
53 | /** | |
54 | * transport_class_unregister - unregister a previously registered class | |
55 | * | |
56 | * @tclass: The transport class to unregister | |
57 | * | |
58 | * Must be called prior to deallocating the memory for the transport | |
59 | * class. | |
60 | */ | |
61 | void transport_class_unregister(struct transport_class *tclass) | |
62 | { | |
63 | class_unregister(&tclass->class); | |
64 | } | |
65 | EXPORT_SYMBOL_GPL(transport_class_unregister); | |
66 | ||
d0a7e574 JB |
67 | static int anon_transport_dummy_function(struct transport_container *tc, |
68 | struct device *dev, | |
ee959b00 | 69 | struct device *cdev) |
1da177e4 LT |
70 | { |
71 | /* do nothing */ | |
72 | return 0; | |
73 | } | |
74 | ||
75 | /** | |
76 | * anon_transport_class_register - register an anonymous class | |
77 | * | |
78 | * @atc: The anon transport class to register | |
79 | * | |
80 | * The anonymous transport class contains both a transport class and a | |
81 | * container. The idea of an anonymous class is that it never | |
82 | * actually has any device attributes associated with it (and thus | |
83 | * saves on container storage). So it can only be used for triggering | |
84 | * events. Use prezero and then use DECLARE_ANON_TRANSPORT_CLASS() to | |
85 | * initialise the anon transport class storage. | |
86 | */ | |
87 | int anon_transport_class_register(struct anon_transport_class *atc) | |
88 | { | |
89 | int error; | |
90 | atc->container.class = &atc->tclass.class; | |
91 | attribute_container_set_no_classdevs(&atc->container); | |
92 | error = attribute_container_register(&atc->container); | |
93 | if (error) | |
94 | return error; | |
95 | atc->tclass.setup = anon_transport_dummy_function; | |
96 | atc->tclass.remove = anon_transport_dummy_function; | |
97 | return 0; | |
98 | } | |
99 | EXPORT_SYMBOL_GPL(anon_transport_class_register); | |
100 | ||
101 | /** | |
102 | * anon_transport_class_unregister - unregister an anon class | |
103 | * | |
104 | * @atc: Pointer to the anon transport class to unregister | |
105 | * | |
106 | * Must be called prior to deallocating the memory for the anon | |
107 | * transport class. | |
108 | */ | |
109 | void anon_transport_class_unregister(struct anon_transport_class *atc) | |
110 | { | |
2f3edc69 JB |
111 | if (unlikely(attribute_container_unregister(&atc->container))) |
112 | BUG(); | |
1da177e4 LT |
113 | } |
114 | EXPORT_SYMBOL_GPL(anon_transport_class_unregister); | |
115 | ||
116 | static int transport_setup_classdev(struct attribute_container *cont, | |
117 | struct device *dev, | |
ee959b00 | 118 | struct device *classdev) |
1da177e4 LT |
119 | { |
120 | struct transport_class *tclass = class_to_transport_class(cont->class); | |
d0a7e574 | 121 | struct transport_container *tcont = attribute_container_to_transport_container(cont); |
1da177e4 LT |
122 | |
123 | if (tclass->setup) | |
d0a7e574 | 124 | tclass->setup(tcont, dev, classdev); |
1da177e4 LT |
125 | |
126 | return 0; | |
127 | } | |
128 | ||
129 | /** | |
0643245f | 130 | * transport_setup_device - declare a new dev for transport class association but don't make it visible yet. |
1da177e4 LT |
131 | * @dev: the generic device representing the entity being added |
132 | * | |
133 | * Usually, dev represents some component in the HBA system (either | |
134 | * the HBA itself or a device remote across the HBA bus). This | |
135 | * routine is simply a trigger point to see if any set of transport | |
136 | * classes wishes to associate with the added device. This allocates | |
137 | * storage for the class device and initialises it, but does not yet | |
138 | * add it to the system or add attributes to it (you do this with | |
139 | * transport_add_device). If you have no need for a separate setup | |
140 | * and add operations, use transport_register_device (see | |
141 | * transport_class.h). | |
142 | */ | |
143 | ||
144 | void transport_setup_device(struct device *dev) | |
145 | { | |
146 | attribute_container_add_device(dev, transport_setup_classdev); | |
147 | } | |
148 | EXPORT_SYMBOL_GPL(transport_setup_device); | |
149 | ||
150 | static int transport_add_class_device(struct attribute_container *cont, | |
151 | struct device *dev, | |
ee959b00 | 152 | struct device *classdev) |
1da177e4 LT |
153 | { |
154 | int error = attribute_container_add_class_device(classdev); | |
155 | struct transport_container *tcont = | |
156 | attribute_container_to_transport_container(cont); | |
157 | ||
158 | if (!error && tcont->statistics) | |
159 | error = sysfs_create_group(&classdev->kobj, tcont->statistics); | |
160 | ||
161 | return error; | |
162 | } | |
163 | ||
164 | ||
165 | /** | |
166 | * transport_add_device - declare a new dev for transport class association | |
167 | * | |
168 | * @dev: the generic device representing the entity being added | |
169 | * | |
170 | * Usually, dev represents some component in the HBA system (either | |
171 | * the HBA itself or a device remote across the HBA bus). This | |
172 | * routine is simply a trigger point used to add the device to the | |
173 | * system and register attributes for it. | |
174 | */ | |
175 | ||
176 | void transport_add_device(struct device *dev) | |
177 | { | |
178 | attribute_container_device_trigger(dev, transport_add_class_device); | |
179 | } | |
180 | EXPORT_SYMBOL_GPL(transport_add_device); | |
181 | ||
182 | static int transport_configure(struct attribute_container *cont, | |
d0a7e574 | 183 | struct device *dev, |
ee959b00 | 184 | struct device *cdev) |
1da177e4 LT |
185 | { |
186 | struct transport_class *tclass = class_to_transport_class(cont->class); | |
d0a7e574 | 187 | struct transport_container *tcont = attribute_container_to_transport_container(cont); |
1da177e4 LT |
188 | |
189 | if (tclass->configure) | |
d0a7e574 | 190 | tclass->configure(tcont, dev, cdev); |
1da177e4 LT |
191 | |
192 | return 0; | |
193 | } | |
194 | ||
195 | /** | |
196 | * transport_configure_device - configure an already set up device | |
197 | * | |
198 | * @dev: generic device representing device to be configured | |
199 | * | |
200 | * The idea of configure is simply to provide a point within the setup | |
201 | * process to allow the transport class to extract information from a | |
202 | * device after it has been setup. This is used in SCSI because we | |
203 | * have to have a setup device to begin using the HBA, but after we | |
204 | * send the initial inquiry, we use configure to extract the device | |
205 | * parameters. The device need not have been added to be configured. | |
206 | */ | |
207 | void transport_configure_device(struct device *dev) | |
208 | { | |
d0a7e574 | 209 | attribute_container_device_trigger(dev, transport_configure); |
1da177e4 LT |
210 | } |
211 | EXPORT_SYMBOL_GPL(transport_configure_device); | |
212 | ||
213 | static int transport_remove_classdev(struct attribute_container *cont, | |
214 | struct device *dev, | |
ee959b00 | 215 | struct device *classdev) |
1da177e4 LT |
216 | { |
217 | struct transport_container *tcont = | |
218 | attribute_container_to_transport_container(cont); | |
219 | struct transport_class *tclass = class_to_transport_class(cont->class); | |
220 | ||
221 | if (tclass->remove) | |
d0a7e574 | 222 | tclass->remove(tcont, dev, classdev); |
1da177e4 LT |
223 | |
224 | if (tclass->remove != anon_transport_dummy_function) { | |
225 | if (tcont->statistics) | |
226 | sysfs_remove_group(&classdev->kobj, tcont->statistics); | |
227 | attribute_container_class_device_del(classdev); | |
228 | } | |
229 | ||
230 | return 0; | |
231 | } | |
232 | ||
233 | ||
234 | /** | |
235 | * transport_remove_device - remove the visibility of a device | |
236 | * | |
237 | * @dev: generic device to remove | |
238 | * | |
239 | * This call removes the visibility of the device (to the user from | |
240 | * sysfs), but does not destroy it. To eliminate a device entirely | |
241 | * you must also call transport_destroy_device. If you don't need to | |
242 | * do remove and destroy as separate operations, use | |
243 | * transport_unregister_device() (see transport_class.h) which will | |
244 | * perform both calls for you. | |
245 | */ | |
246 | void transport_remove_device(struct device *dev) | |
247 | { | |
248 | attribute_container_device_trigger(dev, transport_remove_classdev); | |
249 | } | |
250 | EXPORT_SYMBOL_GPL(transport_remove_device); | |
251 | ||
252 | static void transport_destroy_classdev(struct attribute_container *cont, | |
253 | struct device *dev, | |
ee959b00 | 254 | struct device *classdev) |
1da177e4 LT |
255 | { |
256 | struct transport_class *tclass = class_to_transport_class(cont->class); | |
257 | ||
258 | if (tclass->remove != anon_transport_dummy_function) | |
ee959b00 | 259 | put_device(classdev); |
1da177e4 LT |
260 | } |
261 | ||
262 | ||
263 | /** | |
264 | * transport_destroy_device - destroy a removed device | |
265 | * | |
266 | * @dev: device to eliminate from the transport class. | |
267 | * | |
268 | * This call triggers the elimination of storage associated with the | |
269 | * transport classdev. Note: all it really does is relinquish a | |
270 | * reference to the classdev. The memory will not be freed until the | |
271 | * last reference goes to zero. Note also that the classdev retains a | |
272 | * reference count on dev, so dev too will remain for as long as the | |
273 | * transport class device remains around. | |
274 | */ | |
275 | void transport_destroy_device(struct device *dev) | |
276 | { | |
277 | attribute_container_remove_device(dev, transport_destroy_classdev); | |
278 | } | |
279 | EXPORT_SYMBOL_GPL(transport_destroy_device); |