Branch data Line data Source code
1 : : // SPDX-License-Identifier: GPL-2.0 2 : : /* 3 : : * transport_class.c - implementation of generic transport classes 4 : : * using attribute_containers 5 : : * 6 : : * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com> 7 : : * 8 : : * The basic idea here is to allow any "device controller" (which 9 : : * would most often be a Host Bus Adapter to use the services of one 10 : : * or more tranport classes for performing transport specific 11 : : * services. Transport specific services are things that the generic 12 : : * command layer doesn't want to know about (speed settings, line 13 : : * condidtioning, etc), but which the user might be interested in. 14 : : * Thus, the HBA's use the routines exported by the transport classes 15 : : * to perform these functions. The transport classes export certain 16 : : * values to the user via sysfs using attribute containers. 17 : : * 18 : : * Note: because not every HBA will care about every transport 19 : : * attribute, there's a many to one relationship that goes like this: 20 : : * 21 : : * transport class<-----attribute container<----class device 22 : : * 23 : : * Usually the attribute container is per-HBA, but the design doesn't 24 : : * mandate that. Although most of the services will be specific to 25 : : * the actual external storage connection used by the HBA, the generic 26 : : * transport class is framed entirely in terms of generic devices to 27 : : * allow it to be used by any physical HBA in the system. 28 : : */ 29 : : #include <linux/export.h> 30 : : #include <linux/attribute_container.h> 31 : : #include <linux/transport_class.h> 32 : : 33 : : static int transport_remove_classdev(struct attribute_container *cont, 34 : : struct device *dev, 35 : : struct device *classdev); 36 : : 37 : : /** 38 : : * transport_class_register - register an initial transport class 39 : : * 40 : : * @tclass: a pointer to the transport class structure to be initialised 41 : : * 42 : : * The transport class contains an embedded class which is used to 43 : : * identify it. The caller should initialise this structure with 44 : : * zeros and then generic class must have been initialised with the 45 : : * actual transport class unique name. There's a macro 46 : : * DECLARE_TRANSPORT_CLASS() to do this (declared classes still must 47 : : * be registered). 48 : : * 49 : : * Returns 0 on success or error on failure. 50 : : */ 51 : 15 : int transport_class_register(struct transport_class *tclass) 52 : : { 53 : 15 : return class_register(&tclass->class); 54 : : } 55 : : EXPORT_SYMBOL_GPL(transport_class_register); 56 : : 57 : : /** 58 : : * transport_class_unregister - unregister a previously registered class 59 : : * 60 : : * @tclass: The transport class to unregister 61 : : * 62 : : * Must be called prior to deallocating the memory for the transport 63 : : * class. 64 : : */ 65 : 0 : void transport_class_unregister(struct transport_class *tclass) 66 : : { 67 : 0 : class_unregister(&tclass->class); 68 : 0 : } 69 : : EXPORT_SYMBOL_GPL(transport_class_unregister); 70 : : 71 : 0 : static int anon_transport_dummy_function(struct transport_container *tc, 72 : : struct device *dev, 73 : : struct device *cdev) 74 : : { 75 : : /* do nothing */ 76 : 0 : return 0; 77 : : } 78 : : 79 : : /** 80 : : * anon_transport_class_register - register an anonymous class 81 : : * 82 : : * @atc: The anon transport class to register 83 : : * 84 : : * The anonymous transport class contains both a transport class and a 85 : : * container. The idea of an anonymous class is that it never 86 : : * actually has any device attributes associated with it (and thus 87 : : * saves on container storage). So it can only be used for triggering 88 : : * events. Use prezero and then use DECLARE_ANON_TRANSPORT_CLASS() to 89 : : * initialise the anon transport class storage. 90 : : */ 91 : 3 : int anon_transport_class_register(struct anon_transport_class *atc) 92 : : { 93 : 3 : int error; 94 : 3 : atc->container.class = &atc->tclass.class; 95 : 3 : attribute_container_set_no_classdevs(&atc->container); 96 : 3 : error = attribute_container_register(&atc->container); 97 [ + - ]: 3 : if (error) 98 : : return error; 99 : 3 : atc->tclass.setup = anon_transport_dummy_function; 100 : 3 : atc->tclass.remove = anon_transport_dummy_function; 101 : 3 : return 0; 102 : : } 103 : : EXPORT_SYMBOL_GPL(anon_transport_class_register); 104 : : 105 : : /** 106 : : * anon_transport_class_unregister - unregister an anon class 107 : : * 108 : : * @atc: Pointer to the anon transport class to unregister 109 : : * 110 : : * Must be called prior to deallocating the memory for the anon 111 : : * transport class. 112 : : */ 113 : 0 : void anon_transport_class_unregister(struct anon_transport_class *atc) 114 : : { 115 [ # # ]: 0 : if (unlikely(attribute_container_unregister(&atc->container))) 116 : 0 : BUG(); 117 : 0 : } 118 : : EXPORT_SYMBOL_GPL(anon_transport_class_unregister); 119 : : 120 : 24 : static int transport_setup_classdev(struct attribute_container *cont, 121 : : struct device *dev, 122 : : struct device *classdev) 123 : : { 124 : 24 : struct transport_class *tclass = class_to_transport_class(cont->class); 125 : 24 : struct transport_container *tcont = attribute_container_to_transport_container(cont); 126 : : 127 [ - + ]: 24 : if (tclass->setup) 128 : 0 : tclass->setup(tcont, dev, classdev); 129 : : 130 : 24 : return 0; 131 : : } 132 : : 133 : : /** 134 : : * transport_setup_device - declare a new dev for transport class association but don't make it visible yet. 135 : : * @dev: the generic device representing the entity being added 136 : : * 137 : : * Usually, dev represents some component in the HBA system (either 138 : : * the HBA itself or a device remote across the HBA bus). This 139 : : * routine is simply a trigger point to see if any set of transport 140 : : * classes wishes to associate with the added device. This allocates 141 : : * storage for the class device and initialises it, but does not yet 142 : : * add it to the system or add attributes to it (you do this with 143 : : * transport_add_device). If you have no need for a separate setup 144 : : * and add operations, use transport_register_device (see 145 : : * transport_class.h). 146 : : */ 147 : : 148 : 48 : void transport_setup_device(struct device *dev) 149 : : { 150 : 48 : attribute_container_add_device(dev, transport_setup_classdev); 151 : 48 : } 152 : : EXPORT_SYMBOL_GPL(transport_setup_device); 153 : : 154 : 24 : static int transport_add_class_device(struct attribute_container *cont, 155 : : struct device *dev, 156 : : struct device *classdev) 157 : : { 158 : 24 : int error = attribute_container_add_class_device(classdev); 159 : 24 : struct transport_container *tcont = 160 : 24 : attribute_container_to_transport_container(cont); 161 : : 162 [ + - - + ]: 24 : if (!error && tcont->statistics) 163 : 0 : error = sysfs_create_group(&classdev->kobj, tcont->statistics); 164 : : 165 : 24 : return error; 166 : : } 167 : : 168 : : 169 : : /** 170 : : * transport_add_device - declare a new dev for transport class association 171 : : * 172 : : * @dev: the generic device representing the entity being added 173 : : * 174 : : * Usually, dev represents some component in the HBA system (either 175 : : * the HBA itself or a device remote across the HBA bus). This 176 : : * routine is simply a trigger point used to add the device to the 177 : : * system and register attributes for it. 178 : : */ 179 : 48 : int transport_add_device(struct device *dev) 180 : : { 181 : 48 : return attribute_container_device_trigger_safe(dev, 182 : : transport_add_class_device, 183 : : transport_remove_classdev); 184 : : } 185 : : EXPORT_SYMBOL_GPL(transport_add_device); 186 : : 187 : 24 : static int transport_configure(struct attribute_container *cont, 188 : : struct device *dev, 189 : : struct device *cdev) 190 : : { 191 : 24 : struct transport_class *tclass = class_to_transport_class(cont->class); 192 : 24 : struct transport_container *tcont = attribute_container_to_transport_container(cont); 193 : : 194 [ - + ]: 24 : if (tclass->configure) 195 : 0 : tclass->configure(tcont, dev, cdev); 196 : : 197 : 24 : return 0; 198 : : } 199 : : 200 : : /** 201 : : * transport_configure_device - configure an already set up device 202 : : * 203 : : * @dev: generic device representing device to be configured 204 : : * 205 : : * The idea of configure is simply to provide a point within the setup 206 : : * process to allow the transport class to extract information from a 207 : : * device after it has been setup. This is used in SCSI because we 208 : : * have to have a setup device to begin using the HBA, but after we 209 : : * send the initial inquiry, we use configure to extract the device 210 : : * parameters. The device need not have been added to be configured. 211 : : */ 212 : 48 : void transport_configure_device(struct device *dev) 213 : : { 214 : 48 : attribute_container_device_trigger(dev, transport_configure); 215 : 48 : } 216 : : EXPORT_SYMBOL_GPL(transport_configure_device); 217 : : 218 : 0 : static int transport_remove_classdev(struct attribute_container *cont, 219 : : struct device *dev, 220 : : struct device *classdev) 221 : : { 222 : 0 : struct transport_container *tcont = 223 : 0 : attribute_container_to_transport_container(cont); 224 : 0 : struct transport_class *tclass = class_to_transport_class(cont->class); 225 : : 226 [ # # ]: 0 : if (tclass->remove) 227 : 0 : tclass->remove(tcont, dev, classdev); 228 : : 229 [ # # ]: 0 : if (tclass->remove != anon_transport_dummy_function) { 230 [ # # ]: 0 : if (tcont->statistics) 231 : 0 : sysfs_remove_group(&classdev->kobj, tcont->statistics); 232 : 0 : attribute_container_class_device_del(classdev); 233 : : } 234 : : 235 : 0 : return 0; 236 : : } 237 : : 238 : : 239 : : /** 240 : : * transport_remove_device - remove the visibility of a device 241 : : * 242 : : * @dev: generic device to remove 243 : : * 244 : : * This call removes the visibility of the device (to the user from 245 : : * sysfs), but does not destroy it. To eliminate a device entirely 246 : : * you must also call transport_destroy_device. If you don't need to 247 : : * do remove and destroy as separate operations, use 248 : : * transport_unregister_device() (see transport_class.h) which will 249 : : * perform both calls for you. 250 : : */ 251 : 0 : void transport_remove_device(struct device *dev) 252 : : { 253 : 0 : attribute_container_device_trigger(dev, transport_remove_classdev); 254 : 0 : } 255 : : EXPORT_SYMBOL_GPL(transport_remove_device); 256 : : 257 : 0 : static void transport_destroy_classdev(struct attribute_container *cont, 258 : : struct device *dev, 259 : : struct device *classdev) 260 : : { 261 : 0 : struct transport_class *tclass = class_to_transport_class(cont->class); 262 : : 263 [ # # ]: 0 : if (tclass->remove != anon_transport_dummy_function) 264 : 0 : put_device(classdev); 265 : 0 : } 266 : : 267 : : 268 : : /** 269 : : * transport_destroy_device - destroy a removed device 270 : : * 271 : : * @dev: device to eliminate from the transport class. 272 : : * 273 : : * This call triggers the elimination of storage associated with the 274 : : * transport classdev. Note: all it really does is relinquish a 275 : : * reference to the classdev. The memory will not be freed until the 276 : : * last reference goes to zero. Note also that the classdev retains a 277 : : * reference count on dev, so dev too will remain for as long as the 278 : : * transport class device remains around. 279 : : */ 280 : 0 : void transport_destroy_device(struct device *dev) 281 : : { 282 : 0 : attribute_container_remove_device(dev, transport_destroy_classdev); 283 : 0 : } 284 : : EXPORT_SYMBOL_GPL(transport_destroy_device);