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