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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * FPGA Bridge Framework Driver
4 *
5 * Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
6 * Copyright (C) 2017 Intel Corporation
7 */
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 bridge
24 *
25 * @bridge: FPGA bridge
26 *
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 bridge
42 *
43 * @bridge: FPGA bridge
44 *
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 bridge
82 *
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 bridge
116 * @dev: parent device that fpga bridge was registered with
117 * @info: fpga image specific information
118 *
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 bridge
144 *
145 * @bridge: FPGA bridge
146 */
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 list
160 * @bridge_list: list of FPGA bridges
161 *
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 list
183 *
184 * @bridge_list: list of FPGA bridges
185 *
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 bridges
207 *
208 * @bridge_list: list of FPGA bridges
209 *
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 list
230 *
231 * @np: node pointer of an FPGA bridge
232 * @info: fpga image specific information
233 * @bridge_list: list of FPGA bridges
234 *
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 list
260 *
261 * @dev: FPGA bridge device
262 * @info: fpga image specific information
263 * @bridge_list: list of FPGA bridges
264 *
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 sysfs_emit(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 device
323 * @parent: FPGA bridge device from pdev
324 * @name: FPGA bridge name
325 * @br_ops: pointer to structure of fpga bridge ops
326 * @priv: FPGA bridge private data
327 * @owner: owner module containing the br_ops
328 *
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_obj(*bridge);
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 bridge
398 *
399 * @bridge: FPGA bridge struct
400 *
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 into
407 * 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 <[email protected]>");
443MODULE_LICENSE("GPL v2");
444
445subsys_initcall(fpga_bridge_dev_init);
446module_exit(fpga_bridge_dev_exit);