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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 | |
10 | * would most often be a Host Bus Adapter" to use the services of one | |
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 | ||
67 | static int anon_transport_dummy_function(struct device *dev) | |
68 | { | |
69 | /* do nothing */ | |
70 | return 0; | |
71 | } | |
72 | ||
73 | /** | |
74 | * anon_transport_class_register - register an anonymous class | |
75 | * | |
76 | * @atc: The anon transport class to register | |
77 | * | |
78 | * The anonymous transport class contains both a transport class and a | |
79 | * container. The idea of an anonymous class is that it never | |
80 | * actually has any device attributes associated with it (and thus | |
81 | * saves on container storage). So it can only be used for triggering | |
82 | * events. Use prezero and then use DECLARE_ANON_TRANSPORT_CLASS() to | |
83 | * initialise the anon transport class storage. | |
84 | */ | |
85 | int anon_transport_class_register(struct anon_transport_class *atc) | |
86 | { | |
87 | int error; | |
88 | atc->container.class = &atc->tclass.class; | |
89 | attribute_container_set_no_classdevs(&atc->container); | |
90 | error = attribute_container_register(&atc->container); | |
91 | if (error) | |
92 | return error; | |
93 | atc->tclass.setup = anon_transport_dummy_function; | |
94 | atc->tclass.remove = anon_transport_dummy_function; | |
95 | return 0; | |
96 | } | |
97 | EXPORT_SYMBOL_GPL(anon_transport_class_register); | |
98 | ||
99 | /** | |
100 | * anon_transport_class_unregister - unregister an anon class | |
101 | * | |
102 | * @atc: Pointer to the anon transport class to unregister | |
103 | * | |
104 | * Must be called prior to deallocating the memory for the anon | |
105 | * transport class. | |
106 | */ | |
107 | void anon_transport_class_unregister(struct anon_transport_class *atc) | |
108 | { | |
109 | attribute_container_unregister(&atc->container); | |
110 | } | |
111 | EXPORT_SYMBOL_GPL(anon_transport_class_unregister); | |
112 | ||
113 | static int transport_setup_classdev(struct attribute_container *cont, | |
114 | struct device *dev, | |
115 | struct class_device *classdev) | |
116 | { | |
117 | struct transport_class *tclass = class_to_transport_class(cont->class); | |
118 | ||
119 | if (tclass->setup) | |
120 | tclass->setup(dev); | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | /** | |
126 | * transport_setup_device - declare a new dev for transport class association | |
127 | * but don't make it visible yet. | |
128 | * | |
129 | * @dev: the generic device representing the entity being added | |
130 | * | |
131 | * Usually, dev represents some component in the HBA system (either | |
132 | * the HBA itself or a device remote across the HBA bus). This | |
133 | * routine is simply a trigger point to see if any set of transport | |
134 | * classes wishes to associate with the added device. This allocates | |
135 | * storage for the class device and initialises it, but does not yet | |
136 | * add it to the system or add attributes to it (you do this with | |
137 | * transport_add_device). If you have no need for a separate setup | |
138 | * and add operations, use transport_register_device (see | |
139 | * transport_class.h). | |
140 | */ | |
141 | ||
142 | void transport_setup_device(struct device *dev) | |
143 | { | |
144 | attribute_container_add_device(dev, transport_setup_classdev); | |
145 | } | |
146 | EXPORT_SYMBOL_GPL(transport_setup_device); | |
147 | ||
148 | static int transport_add_class_device(struct attribute_container *cont, | |
149 | struct device *dev, | |
150 | struct class_device *classdev) | |
151 | { | |
152 | int error = attribute_container_add_class_device(classdev); | |
153 | struct transport_container *tcont = | |
154 | attribute_container_to_transport_container(cont); | |
155 | ||
156 | if (!error && tcont->statistics) | |
157 | error = sysfs_create_group(&classdev->kobj, tcont->statistics); | |
158 | ||
159 | return error; | |
160 | } | |
161 | ||
162 | ||
163 | /** | |
164 | * transport_add_device - declare a new dev for transport class association | |
165 | * | |
166 | * @dev: the generic device representing the entity being added | |
167 | * | |
168 | * Usually, dev represents some component in the HBA system (either | |
169 | * the HBA itself or a device remote across the HBA bus). This | |
170 | * routine is simply a trigger point used to add the device to the | |
171 | * system and register attributes for it. | |
172 | */ | |
173 | ||
174 | void transport_add_device(struct device *dev) | |
175 | { | |
176 | attribute_container_device_trigger(dev, transport_add_class_device); | |
177 | } | |
178 | EXPORT_SYMBOL_GPL(transport_add_device); | |
179 | ||
180 | static int transport_configure(struct attribute_container *cont, | |
181 | struct device *dev) | |
182 | { | |
183 | struct transport_class *tclass = class_to_transport_class(cont->class); | |
184 | ||
185 | if (tclass->configure) | |
186 | tclass->configure(dev); | |
187 | ||
188 | return 0; | |
189 | } | |
190 | ||
191 | /** | |
192 | * transport_configure_device - configure an already set up device | |
193 | * | |
194 | * @dev: generic device representing device to be configured | |
195 | * | |
196 | * The idea of configure is simply to provide a point within the setup | |
197 | * process to allow the transport class to extract information from a | |
198 | * device after it has been setup. This is used in SCSI because we | |
199 | * have to have a setup device to begin using the HBA, but after we | |
200 | * send the initial inquiry, we use configure to extract the device | |
201 | * parameters. The device need not have been added to be configured. | |
202 | */ | |
203 | void transport_configure_device(struct device *dev) | |
204 | { | |
205 | attribute_container_trigger(dev, transport_configure); | |
206 | } | |
207 | EXPORT_SYMBOL_GPL(transport_configure_device); | |
208 | ||
209 | static int transport_remove_classdev(struct attribute_container *cont, | |
210 | struct device *dev, | |
211 | struct class_device *classdev) | |
212 | { | |
213 | struct transport_container *tcont = | |
214 | attribute_container_to_transport_container(cont); | |
215 | struct transport_class *tclass = class_to_transport_class(cont->class); | |
216 | ||
217 | if (tclass->remove) | |
218 | tclass->remove(dev); | |
219 | ||
220 | if (tclass->remove != anon_transport_dummy_function) { | |
221 | if (tcont->statistics) | |
222 | sysfs_remove_group(&classdev->kobj, tcont->statistics); | |
223 | attribute_container_class_device_del(classdev); | |
224 | } | |
225 | ||
226 | return 0; | |
227 | } | |
228 | ||
229 | ||
230 | /** | |
231 | * transport_remove_device - remove the visibility of a device | |
232 | * | |
233 | * @dev: generic device to remove | |
234 | * | |
235 | * This call removes the visibility of the device (to the user from | |
236 | * sysfs), but does not destroy it. To eliminate a device entirely | |
237 | * you must also call transport_destroy_device. If you don't need to | |
238 | * do remove and destroy as separate operations, use | |
239 | * transport_unregister_device() (see transport_class.h) which will | |
240 | * perform both calls for you. | |
241 | */ | |
242 | void transport_remove_device(struct device *dev) | |
243 | { | |
244 | attribute_container_device_trigger(dev, transport_remove_classdev); | |
245 | } | |
246 | EXPORT_SYMBOL_GPL(transport_remove_device); | |
247 | ||
248 | static void transport_destroy_classdev(struct attribute_container *cont, | |
249 | struct device *dev, | |
250 | struct class_device *classdev) | |
251 | { | |
252 | struct transport_class *tclass = class_to_transport_class(cont->class); | |
253 | ||
254 | if (tclass->remove != anon_transport_dummy_function) | |
255 | class_device_put(classdev); | |
256 | } | |
257 | ||
258 | ||
259 | /** | |
260 | * transport_destroy_device - destroy a removed device | |
261 | * | |
262 | * @dev: device to eliminate from the transport class. | |
263 | * | |
264 | * This call triggers the elimination of storage associated with the | |
265 | * transport classdev. Note: all it really does is relinquish a | |
266 | * reference to the classdev. The memory will not be freed until the | |
267 | * last reference goes to zero. Note also that the classdev retains a | |
268 | * reference count on dev, so dev too will remain for as long as the | |
269 | * transport class device remains around. | |
270 | */ | |
271 | void transport_destroy_device(struct device *dev) | |
272 | { | |
273 | attribute_container_remove_device(dev, transport_destroy_classdev); | |
274 | } | |
275 | EXPORT_SYMBOL_GPL(transport_destroy_device); |