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1// SPDX-License-Identifier: GPL-2.02/*3 * FPGA Bridge Framework Driver4 *5 * Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.6 * Copyright (C) 2017 Intel Corporation7 */8#include <linux/fpga/fpga-bridge.h>9#include <linux/idr.h>10#include <linux/kernel.h>11#include <linux/module.h>12#include <linux/of_platform.h>13#include <linux/slab.h>14#include <linux/spinlock.h>15 16static DEFINE_IDA(fpga_bridge_ida);17static const struct class fpga_bridge_class;18 19/* Lock for adding/removing bridges to linked lists*/20static DEFINE_SPINLOCK(bridge_list_lock);21 22/**23 * fpga_bridge_enable - Enable transactions on the bridge24 *25 * @bridge: FPGA bridge26 *27 * Return: 0 for success, error code otherwise.28 */29int fpga_bridge_enable(struct fpga_bridge *bridge)30{31 dev_dbg(&bridge->dev, "enable\n");32 33 if (bridge->br_ops->enable_set)34 return bridge->br_ops->enable_set(bridge, 1);35 36 return 0;37}38EXPORT_SYMBOL_GPL(fpga_bridge_enable);39 40/**41 * fpga_bridge_disable - Disable transactions on the bridge42 *43 * @bridge: FPGA bridge44 *45 * Return: 0 for success, error code otherwise.46 */47int fpga_bridge_disable(struct fpga_bridge *bridge)48{49 dev_dbg(&bridge->dev, "disable\n");50 51 if (bridge->br_ops->enable_set)52 return bridge->br_ops->enable_set(bridge, 0);53 54 return 0;55}56EXPORT_SYMBOL_GPL(fpga_bridge_disable);57 58static struct fpga_bridge *__fpga_bridge_get(struct device *bridge_dev,59 struct fpga_image_info *info)60{61 struct fpga_bridge *bridge;62 63 bridge = to_fpga_bridge(bridge_dev);64 65 bridge->info = info;66 67 if (!mutex_trylock(&bridge->mutex))68 return ERR_PTR(-EBUSY);69 70 if (!try_module_get(bridge->br_ops_owner)) {71 mutex_unlock(&bridge->mutex);72 return ERR_PTR(-ENODEV);73 }74 75 dev_dbg(&bridge->dev, "get\n");76 77 return bridge;78}79 80/**81 * of_fpga_bridge_get - get an exclusive reference to an fpga bridge82 *83 * @np: node pointer of an FPGA bridge.84 * @info: fpga image specific information.85 *86 * Return:87 * * fpga_bridge struct pointer if successful.88 * * -EBUSY if someone already has a reference to the bridge.89 * * -ENODEV if @np is not an FPGA Bridge or can't take parent driver refcount.90 */91struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,92 struct fpga_image_info *info)93{94 struct fpga_bridge *bridge;95 struct device *bridge_dev;96 97 bridge_dev = class_find_device_by_of_node(&fpga_bridge_class, np);98 if (!bridge_dev)99 return ERR_PTR(-ENODEV);100 101 bridge = __fpga_bridge_get(bridge_dev, info);102 if (IS_ERR(bridge))103 put_device(bridge_dev);104 105 return bridge;106}107EXPORT_SYMBOL_GPL(of_fpga_bridge_get);108 109static int fpga_bridge_dev_match(struct device *dev, const void *data)110{111 return dev->parent == data;112}113 114/**115 * fpga_bridge_get - get an exclusive reference to an fpga bridge116 * @dev: parent device that fpga bridge was registered with117 * @info: fpga image specific information118 *119 * Given a device, get an exclusive reference to an fpga bridge.120 *121 * Return: fpga bridge struct or IS_ERR() condition containing error code.122 */123struct fpga_bridge *fpga_bridge_get(struct device *dev,124 struct fpga_image_info *info)125{126 struct fpga_bridge *bridge;127 struct device *bridge_dev;128 129 bridge_dev = class_find_device(&fpga_bridge_class, NULL, dev,130 fpga_bridge_dev_match);131 if (!bridge_dev)132 return ERR_PTR(-ENODEV);133 134 bridge = __fpga_bridge_get(bridge_dev, info);135 if (IS_ERR(bridge))136 put_device(bridge_dev);137 138 return bridge;139}140EXPORT_SYMBOL_GPL(fpga_bridge_get);141 142/**143 * fpga_bridge_put - release a reference to a bridge144 *145 * @bridge: FPGA bridge146 */147void fpga_bridge_put(struct fpga_bridge *bridge)148{149 dev_dbg(&bridge->dev, "put\n");150 151 bridge->info = NULL;152 module_put(bridge->br_ops_owner);153 mutex_unlock(&bridge->mutex);154 put_device(&bridge->dev);155}156EXPORT_SYMBOL_GPL(fpga_bridge_put);157 158/**159 * fpga_bridges_enable - enable bridges in a list160 * @bridge_list: list of FPGA bridges161 *162 * Enable each bridge in the list. If list is empty, do nothing.163 *164 * Return: 0 for success or empty bridge list or an error code otherwise.165 */166int fpga_bridges_enable(struct list_head *bridge_list)167{168 struct fpga_bridge *bridge;169 int ret;170 171 list_for_each_entry(bridge, bridge_list, node) {172 ret = fpga_bridge_enable(bridge);173 if (ret)174 return ret;175 }176 177 return 0;178}179EXPORT_SYMBOL_GPL(fpga_bridges_enable);180 181/**182 * fpga_bridges_disable - disable bridges in a list183 *184 * @bridge_list: list of FPGA bridges185 *186 * Disable each bridge in the list. If list is empty, do nothing.187 *188 * Return: 0 for success or empty bridge list or an error code otherwise.189 */190int fpga_bridges_disable(struct list_head *bridge_list)191{192 struct fpga_bridge *bridge;193 int ret;194 195 list_for_each_entry(bridge, bridge_list, node) {196 ret = fpga_bridge_disable(bridge);197 if (ret)198 return ret;199 }200 201 return 0;202}203EXPORT_SYMBOL_GPL(fpga_bridges_disable);204 205/**206 * fpga_bridges_put - put bridges207 *208 * @bridge_list: list of FPGA bridges209 *210 * For each bridge in the list, put the bridge and remove it from the list.211 * If list is empty, do nothing.212 */213void fpga_bridges_put(struct list_head *bridge_list)214{215 struct fpga_bridge *bridge, *next;216 unsigned long flags;217 218 list_for_each_entry_safe(bridge, next, bridge_list, node) {219 fpga_bridge_put(bridge);220 221 spin_lock_irqsave(&bridge_list_lock, flags);222 list_del(&bridge->node);223 spin_unlock_irqrestore(&bridge_list_lock, flags);224 }225}226EXPORT_SYMBOL_GPL(fpga_bridges_put);227 228/**229 * of_fpga_bridge_get_to_list - get a bridge, add it to a list230 *231 * @np: node pointer of an FPGA bridge232 * @info: fpga image specific information233 * @bridge_list: list of FPGA bridges234 *235 * Get an exclusive reference to the bridge and it to the list.236 *237 * Return: 0 for success, error code from of_fpga_bridge_get() otherwise.238 */239int of_fpga_bridge_get_to_list(struct device_node *np,240 struct fpga_image_info *info,241 struct list_head *bridge_list)242{243 struct fpga_bridge *bridge;244 unsigned long flags;245 246 bridge = of_fpga_bridge_get(np, info);247 if (IS_ERR(bridge))248 return PTR_ERR(bridge);249 250 spin_lock_irqsave(&bridge_list_lock, flags);251 list_add(&bridge->node, bridge_list);252 spin_unlock_irqrestore(&bridge_list_lock, flags);253 254 return 0;255}256EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);257 258/**259 * fpga_bridge_get_to_list - given device, get a bridge, add it to a list260 *261 * @dev: FPGA bridge device262 * @info: fpga image specific information263 * @bridge_list: list of FPGA bridges264 *265 * Get an exclusive reference to the bridge and it to the list.266 *267 * Return: 0 for success, error code from fpga_bridge_get() otherwise.268 */269int fpga_bridge_get_to_list(struct device *dev,270 struct fpga_image_info *info,271 struct list_head *bridge_list)272{273 struct fpga_bridge *bridge;274 unsigned long flags;275 276 bridge = fpga_bridge_get(dev, info);277 if (IS_ERR(bridge))278 return PTR_ERR(bridge);279 280 spin_lock_irqsave(&bridge_list_lock, flags);281 list_add(&bridge->node, bridge_list);282 spin_unlock_irqrestore(&bridge_list_lock, flags);283 284 return 0;285}286EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);287 288static ssize_t name_show(struct device *dev,289 struct device_attribute *attr, char *buf)290{291 struct fpga_bridge *bridge = to_fpga_bridge(dev);292 293 return sprintf(buf, "%s\n", bridge->name);294}295 296static ssize_t state_show(struct device *dev,297 struct device_attribute *attr, char *buf)298{299 struct fpga_bridge *bridge = to_fpga_bridge(dev);300 int state = 1;301 302 if (bridge->br_ops->enable_show) {303 state = bridge->br_ops->enable_show(bridge);304 if (state < 0)305 return state;306 }307 308 return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");309}310 311static DEVICE_ATTR_RO(name);312static DEVICE_ATTR_RO(state);313 314static struct attribute *fpga_bridge_attrs[] = {315 &dev_attr_name.attr,316 &dev_attr_state.attr,317 NULL,318};319ATTRIBUTE_GROUPS(fpga_bridge);320 321/**322 * __fpga_bridge_register - create and register an FPGA Bridge device323 * @parent: FPGA bridge device from pdev324 * @name: FPGA bridge name325 * @br_ops: pointer to structure of fpga bridge ops326 * @priv: FPGA bridge private data327 * @owner: owner module containing the br_ops328 *329 * Return: struct fpga_bridge pointer or ERR_PTR()330 */331struct fpga_bridge *332__fpga_bridge_register(struct device *parent, const char *name,333 const struct fpga_bridge_ops *br_ops,334 void *priv, struct module *owner)335{336 struct fpga_bridge *bridge;337 int id, ret;338 339 if (!br_ops) {340 dev_err(parent, "Attempt to register without fpga_bridge_ops\n");341 return ERR_PTR(-EINVAL);342 }343 344 if (!name || !strlen(name)) {345 dev_err(parent, "Attempt to register with no name!\n");346 return ERR_PTR(-EINVAL);347 }348 349 bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);350 if (!bridge)351 return ERR_PTR(-ENOMEM);352 353 id = ida_alloc(&fpga_bridge_ida, GFP_KERNEL);354 if (id < 0) {355 ret = id;356 goto error_kfree;357 }358 359 mutex_init(&bridge->mutex);360 INIT_LIST_HEAD(&bridge->node);361 362 bridge->name = name;363 bridge->br_ops = br_ops;364 bridge->br_ops_owner = owner;365 bridge->priv = priv;366 367 bridge->dev.groups = br_ops->groups;368 bridge->dev.class = &fpga_bridge_class;369 bridge->dev.parent = parent;370 bridge->dev.of_node = parent->of_node;371 bridge->dev.id = id;372 373 ret = dev_set_name(&bridge->dev, "br%d", id);374 if (ret)375 goto error_device;376 377 ret = device_register(&bridge->dev);378 if (ret) {379 put_device(&bridge->dev);380 return ERR_PTR(ret);381 }382 383 of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev);384 385 return bridge;386 387error_device:388 ida_free(&fpga_bridge_ida, id);389error_kfree:390 kfree(bridge);391 392 return ERR_PTR(ret);393}394EXPORT_SYMBOL_GPL(__fpga_bridge_register);395 396/**397 * fpga_bridge_unregister - unregister an FPGA bridge398 *399 * @bridge: FPGA bridge struct400 *401 * This function is intended for use in an FPGA bridge driver's remove function.402 */403void fpga_bridge_unregister(struct fpga_bridge *bridge)404{405 /*406 * If the low level driver provides a method for putting bridge into407 * a desired state upon unregister, do it.408 */409 if (bridge->br_ops->fpga_bridge_remove)410 bridge->br_ops->fpga_bridge_remove(bridge);411 412 device_unregister(&bridge->dev);413}414EXPORT_SYMBOL_GPL(fpga_bridge_unregister);415 416static void fpga_bridge_dev_release(struct device *dev)417{418 struct fpga_bridge *bridge = to_fpga_bridge(dev);419 420 ida_free(&fpga_bridge_ida, bridge->dev.id);421 kfree(bridge);422}423 424static const struct class fpga_bridge_class = {425 .name = "fpga_bridge",426 .dev_groups = fpga_bridge_groups,427 .dev_release = fpga_bridge_dev_release,428};429 430static int __init fpga_bridge_dev_init(void)431{432 return class_register(&fpga_bridge_class);433}434 435static void __exit fpga_bridge_dev_exit(void)436{437 class_unregister(&fpga_bridge_class);438 ida_destroy(&fpga_bridge_ida);439}440 441MODULE_DESCRIPTION("FPGA Bridge Driver");442MODULE_AUTHOR("Alan Tull <atull@kernel.org>");443MODULE_LICENSE("GPL v2");444 445subsys_initcall(fpga_bridge_dev_init);446module_exit(fpga_bridge_dev_exit);447