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 struct class *fpga_bridge_class;
18
19/* Lock for adding/removing bridges to linked lists*/
20static spinlock_t bridge_list_lock;
21
22static int fpga_bridge_of_node_match(struct device *dev, const void *data)
23{
24 return dev->of_node == data;
25}
26
27/**
28 * fpga_bridge_enable - Enable transactions on the bridge
29 *
30 * @bridge: FPGA bridge
31 *
32 * Return: 0 for success, error code otherwise.
33 */
34int fpga_bridge_enable(struct fpga_bridge *bridge)
35{
36 dev_dbg(&bridge->dev, "enable\n");
37
38 if (bridge->br_ops && bridge->br_ops->enable_set)
39 return bridge->br_ops->enable_set(bridge, 1);
40
41 return 0;
42}
43EXPORT_SYMBOL_GPL(fpga_bridge_enable);
44
45/**
46 * fpga_bridge_disable - Disable transactions on the bridge
47 *
48 * @bridge: FPGA bridge
49 *
50 * Return: 0 for success, error code otherwise.
51 */
52int fpga_bridge_disable(struct fpga_bridge *bridge)
53{
54 dev_dbg(&bridge->dev, "disable\n");
55
56 if (bridge->br_ops && bridge->br_ops->enable_set)
57 return bridge->br_ops->enable_set(bridge, 0);
58
59 return 0;
60}
61EXPORT_SYMBOL_GPL(fpga_bridge_disable);
62
63static struct fpga_bridge *__fpga_bridge_get(struct device *dev,
64 struct fpga_image_info *info)
65{
66 struct fpga_bridge *bridge;
67 int ret = -ENODEV;
68
69 bridge = to_fpga_bridge(dev);
70
71 bridge->info = info;
72
73 if (!mutex_trylock(&bridge->mutex)) {
74 ret = -EBUSY;
75 goto err_dev;
76 }
77
78 if (!try_module_get(dev->parent->driver->owner))
79 goto err_ll_mod;
80
81 dev_dbg(&bridge->dev, "get\n");
82
83 return bridge;
84
85err_ll_mod:
86 mutex_unlock(&bridge->mutex);
87err_dev:
88 put_device(dev);
89 return ERR_PTR(ret);
90}
91
92/**
93 * of_fpga_bridge_get - get an exclusive reference to a fpga bridge
94 *
95 * @np: node pointer of a FPGA bridge
96 * @info: fpga image specific information
97 *
98 * Return fpga_bridge struct if successful.
99 * Return -EBUSY if someone already has a reference to the bridge.
100 * Return -ENODEV if @np is not a FPGA Bridge.
101 */
102struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
103 struct fpga_image_info *info)
104{
105 struct device *dev;
106
107 dev = class_find_device(fpga_bridge_class, NULL, np,
108 fpga_bridge_of_node_match);
109 if (!dev)
110 return ERR_PTR(-ENODEV);
111
112 return __fpga_bridge_get(dev, info);
113}
114EXPORT_SYMBOL_GPL(of_fpga_bridge_get);
115
116static int fpga_bridge_dev_match(struct device *dev, const void *data)
117{
118 return dev->parent == data;
119}
120
121/**
122 * fpga_bridge_get - get an exclusive reference to a fpga bridge
123 * @dev: parent device that fpga bridge was registered with
124 * @info: fpga manager info
125 *
126 * Given a device, get an exclusive reference to a fpga bridge.
127 *
128 * Return: fpga bridge struct or IS_ERR() condition containing error code.
129 */
130struct fpga_bridge *fpga_bridge_get(struct device *dev,
131 struct fpga_image_info *info)
132{
133 struct device *bridge_dev;
134
135 bridge_dev = class_find_device(fpga_bridge_class, NULL, dev,
136 fpga_bridge_dev_match);
137 if (!bridge_dev)
138 return ERR_PTR(-ENODEV);
139
140 return __fpga_bridge_get(bridge_dev, info);
141}
142EXPORT_SYMBOL_GPL(fpga_bridge_get);
143
144/**
145 * fpga_bridge_put - release a reference to a bridge
146 *
147 * @bridge: FPGA bridge
148 */
149void fpga_bridge_put(struct fpga_bridge *bridge)
150{
151 dev_dbg(&bridge->dev, "put\n");
152
153 bridge->info = NULL;
154 module_put(bridge->dev.parent->driver->owner);
155 mutex_unlock(&bridge->mutex);
156 put_device(&bridge->dev);
157}
158EXPORT_SYMBOL_GPL(fpga_bridge_put);
159
160/**
161 * fpga_bridges_enable - enable bridges in a list
162 * @bridge_list: list of FPGA bridges
163 *
164 * Enable each bridge in the list. If list is empty, do nothing.
165 *
166 * Return 0 for success or empty bridge list; return error code otherwise.
167 */
168int fpga_bridges_enable(struct list_head *bridge_list)
169{
170 struct fpga_bridge *bridge;
171 int ret;
172
173 list_for_each_entry(bridge, bridge_list, node) {
174 ret = fpga_bridge_enable(bridge);
175 if (ret)
176 return ret;
177 }
178
179 return 0;
180}
181EXPORT_SYMBOL_GPL(fpga_bridges_enable);
182
183/**
184 * fpga_bridges_disable - disable bridges in a list
185 *
186 * @bridge_list: list of FPGA bridges
187 *
188 * Disable each bridge in the list. If list is empty, do nothing.
189 *
190 * Return 0 for success or empty bridge list; return error code otherwise.
191 */
192int fpga_bridges_disable(struct list_head *bridge_list)
193{
194 struct fpga_bridge *bridge;
195 int ret;
196
197 list_for_each_entry(bridge, bridge_list, node) {
198 ret = fpga_bridge_disable(bridge);
199 if (ret)
200 return ret;
201 }
202
203 return 0;
204}
205EXPORT_SYMBOL_GPL(fpga_bridges_disable);
206
207/**
208 * fpga_bridges_put - put bridges
209 *
210 * @bridge_list: list of FPGA bridges
211 *
212 * For each bridge in the list, put the bridge and remove it from the list.
213 * If list is empty, do nothing.
214 */
215void fpga_bridges_put(struct list_head *bridge_list)
216{
217 struct fpga_bridge *bridge, *next;
218 unsigned long flags;
219
220 list_for_each_entry_safe(bridge, next, bridge_list, node) {
221 fpga_bridge_put(bridge);
222
223 spin_lock_irqsave(&bridge_list_lock, flags);
224 list_del(&bridge->node);
225 spin_unlock_irqrestore(&bridge_list_lock, flags);
226 }
227}
228EXPORT_SYMBOL_GPL(fpga_bridges_put);
229
230/**
231 * of_fpga_bridge_get_to_list - get a bridge, add it to a list
232 *
233 * @np: node pointer of a FPGA bridge
234 * @info: fpga image specific information
235 * @bridge_list: list of FPGA bridges
236 *
237 * Get an exclusive reference to the bridge and and it to the list.
238 *
239 * Return 0 for success, error code from of_fpga_bridge_get() othewise.
240 */
241int of_fpga_bridge_get_to_list(struct device_node *np,
242 struct fpga_image_info *info,
243 struct list_head *bridge_list)
244{
245 struct fpga_bridge *bridge;
246 unsigned long flags;
247
248 bridge = of_fpga_bridge_get(np, info);
249 if (IS_ERR(bridge))
250 return PTR_ERR(bridge);
251
252 spin_lock_irqsave(&bridge_list_lock, flags);
253 list_add(&bridge->node, bridge_list);
254 spin_unlock_irqrestore(&bridge_list_lock, flags);
255
256 return 0;
257}
258EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);
259
260/**
261 * fpga_bridge_get_to_list - given device, get a bridge, add it to a list
262 *
263 * @dev: FPGA bridge device
264 * @info: fpga image specific information
265 * @bridge_list: list of FPGA bridges
266 *
267 * Get an exclusive reference to the bridge and and it to the list.
268 *
269 * Return 0 for success, error code from fpga_bridge_get() othewise.
270 */
271int fpga_bridge_get_to_list(struct device *dev,
272 struct fpga_image_info *info,
273 struct list_head *bridge_list)
274{
275 struct fpga_bridge *bridge;
276 unsigned long flags;
277
278 bridge = fpga_bridge_get(dev, info);
279 if (IS_ERR(bridge))
280 return PTR_ERR(bridge);
281
282 spin_lock_irqsave(&bridge_list_lock, flags);
283 list_add(&bridge->node, bridge_list);
284 spin_unlock_irqrestore(&bridge_list_lock, flags);
285
286 return 0;
287}
288EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
289
290static ssize_t name_show(struct device *dev,
291 struct device_attribute *attr, char *buf)
292{
293 struct fpga_bridge *bridge = to_fpga_bridge(dev);
294
295 return sprintf(buf, "%s\n", bridge->name);
296}
297
298static ssize_t state_show(struct device *dev,
299 struct device_attribute *attr, char *buf)
300{
301 struct fpga_bridge *bridge = to_fpga_bridge(dev);
302 int enable = 1;
303
304 if (bridge->br_ops && bridge->br_ops->enable_show)
305 enable = bridge->br_ops->enable_show(bridge);
306
307 return sprintf(buf, "%s\n", enable ? "enabled" : "disabled");
308}
309
310static DEVICE_ATTR_RO(name);
311static DEVICE_ATTR_RO(state);
312
313static struct attribute *fpga_bridge_attrs[] = {
314 &dev_attr_name.attr,
315 &dev_attr_state.attr,
316 NULL,
317};
318ATTRIBUTE_GROUPS(fpga_bridge);
319
320/**
321 * fpga_bridge_create - create and initialize a struct fpga_bridge
322 * @dev: FPGA bridge device from pdev
323 * @name: FPGA bridge name
324 * @br_ops: pointer to structure of fpga bridge ops
325 * @priv: FPGA bridge private data
326 *
327 * The caller of this function is responsible for freeing the bridge with
328 * fpga_bridge_free(). Using devm_fpga_bridge_create() instead is recommended.
329 *
330 * Return: struct fpga_bridge or NULL
331 */
332struct fpga_bridge *fpga_bridge_create(struct device *dev, const char *name,
333 const struct fpga_bridge_ops *br_ops,
334 void *priv)
335{
336 struct fpga_bridge *bridge;
337 int id, ret = 0;
338
339 if (!name || !strlen(name)) {
340 dev_err(dev, "Attempt to register with no name!\n");
341 return NULL;
342 }
343
344 bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
345 if (!bridge)
346 return NULL;
347
348 id = ida_simple_get(&fpga_bridge_ida, 0, 0, GFP_KERNEL);
349 if (id < 0) {
350 ret = id;
351 goto error_kfree;
352 }
353
354 mutex_init(&bridge->mutex);
355 INIT_LIST_HEAD(&bridge->node);
356
357 bridge->name = name;
358 bridge->br_ops = br_ops;
359 bridge->priv = priv;
360
361 device_initialize(&bridge->dev);
362 bridge->dev.groups = br_ops->groups;
363 bridge->dev.class = fpga_bridge_class;
364 bridge->dev.parent = dev;
365 bridge->dev.of_node = dev->of_node;
366 bridge->dev.id = id;
367
368 ret = dev_set_name(&bridge->dev, "br%d", id);
369 if (ret)
370 goto error_device;
371
372 return bridge;
373
374error_device:
375 ida_simple_remove(&fpga_bridge_ida, id);
376error_kfree:
377 kfree(bridge);
378
379 return NULL;
380}
381EXPORT_SYMBOL_GPL(fpga_bridge_create);
382
383/**
384 * fpga_bridge_free - free a fpga bridge created by fpga_bridge_create()
385 * @bridge: FPGA bridge struct
386 */
387void fpga_bridge_free(struct fpga_bridge *bridge)
388{
389 ida_simple_remove(&fpga_bridge_ida, bridge->dev.id);
390 kfree(bridge);
391}
392EXPORT_SYMBOL_GPL(fpga_bridge_free);
393
394static void devm_fpga_bridge_release(struct device *dev, void *res)
395{
396 struct fpga_bridge *bridge = *(struct fpga_bridge **)res;
397
398 fpga_bridge_free(bridge);
399}
400
401/**
402 * devm_fpga_bridge_create - create and init a managed struct fpga_bridge
403 * @dev: FPGA bridge device from pdev
404 * @name: FPGA bridge name
405 * @br_ops: pointer to structure of fpga bridge ops
406 * @priv: FPGA bridge private data
407 *
408 * This function is intended for use in a FPGA bridge driver's probe function.
409 * After the bridge driver creates the struct with devm_fpga_bridge_create(), it
410 * should register the bridge with fpga_bridge_register(). The bridge driver's
411 * remove function should call fpga_bridge_unregister(). The bridge struct
412 * allocated with this function will be freed automatically on driver detach.
413 * This includes the case of a probe function returning error before calling
414 * fpga_bridge_register(), the struct will still get cleaned up.
415 *
416 * Return: struct fpga_bridge or NULL
417 */
418struct fpga_bridge
419*devm_fpga_bridge_create(struct device *dev, const char *name,
420 const struct fpga_bridge_ops *br_ops, void *priv)
421{
422 struct fpga_bridge **ptr, *bridge;
423
424 ptr = devres_alloc(devm_fpga_bridge_release, sizeof(*ptr), GFP_KERNEL);
425 if (!ptr)
426 return NULL;
427
428 bridge = fpga_bridge_create(dev, name, br_ops, priv);
429 if (!bridge) {
430 devres_free(ptr);
431 } else {
432 *ptr = bridge;
433 devres_add(dev, ptr);
434 }
435
436 return bridge;
437}
438EXPORT_SYMBOL_GPL(devm_fpga_bridge_create);
439
440/**
441 * fpga_bridge_register - register a FPGA bridge
442 *
443 * @bridge: FPGA bridge struct
444 *
445 * Return: 0 for success, error code otherwise.
446 */
447int fpga_bridge_register(struct fpga_bridge *bridge)
448{
449 struct device *dev = &bridge->dev;
450 int ret;
451
452 ret = device_add(dev);
453 if (ret)
454 return ret;
455
456 of_platform_populate(dev->of_node, NULL, NULL, dev);
457
458 dev_info(dev->parent, "fpga bridge [%s] registered\n", bridge->name);
459
460 return 0;
461}
462EXPORT_SYMBOL_GPL(fpga_bridge_register);
463
464/**
465 * fpga_bridge_unregister - unregister a FPGA bridge
466 *
467 * @bridge: FPGA bridge struct
468 *
469 * This function is intended for use in a FPGA bridge driver's remove function.
470 */
471void fpga_bridge_unregister(struct fpga_bridge *bridge)
472{
473 /*
474 * If the low level driver provides a method for putting bridge into
475 * a desired state upon unregister, do it.
476 */
477 if (bridge->br_ops && bridge->br_ops->fpga_bridge_remove)
478 bridge->br_ops->fpga_bridge_remove(bridge);
479
480 device_unregister(&bridge->dev);
481}
482EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
483
484static void fpga_bridge_dev_release(struct device *dev)
485{
486}
487
488static int __init fpga_bridge_dev_init(void)
489{
490 spin_lock_init(&bridge_list_lock);
491
492 fpga_bridge_class = class_create(THIS_MODULE, "fpga_bridge");
493 if (IS_ERR(fpga_bridge_class))
494 return PTR_ERR(fpga_bridge_class);
495
496 fpga_bridge_class->dev_groups = fpga_bridge_groups;
497 fpga_bridge_class->dev_release = fpga_bridge_dev_release;
498
499 return 0;
500}
501
502static void __exit fpga_bridge_dev_exit(void)
503{
504 class_destroy(fpga_bridge_class);
505 ida_destroy(&fpga_bridge_ida);
506}
507
508MODULE_DESCRIPTION("FPGA Bridge Driver");
509MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
510MODULE_LICENSE("GPL v2");
511
512subsys_initcall(fpga_bridge_dev_init);
513module_exit(fpga_bridge_dev_exit);
514