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 && 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 && 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 *dev,
59 struct fpga_image_info *info)
60{
61 struct fpga_bridge *bridge;
62 int ret = -ENODEV;
63
64 bridge = to_fpga_bridge(dev);
65
66 bridge->info = info;
67
68 if (!mutex_trylock(lock: &bridge->mutex)) {
69 ret = -EBUSY;
70 goto err_dev;
71 }
72
73 if (!try_module_get(module: dev->parent->driver->owner))
74 goto err_ll_mod;
75
76 dev_dbg(&bridge->dev, "get\n");
77
78 return bridge;
79
80err_ll_mod:
81 mutex_unlock(lock: &bridge->mutex);
82err_dev:
83 put_device(dev);
84 return ERR_PTR(error: ret);
85}
86
87/**
88 * of_fpga_bridge_get - get an exclusive reference to an fpga bridge
89 *
90 * @np: node pointer of an FPGA bridge.
91 * @info: fpga image specific information.
92 *
93 * Return:
94 * * fpga_bridge struct pointer if successful.
95 * * -EBUSY if someone already has a reference to the bridge.
96 * * -ENODEV if @np is not an FPGA Bridge or can't take parent driver refcount.
97 */
98struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
99 struct fpga_image_info *info)
100{
101 struct device *dev;
102
103 dev = class_find_device_by_of_node(class: &fpga_bridge_class, np);
104 if (!dev)
105 return ERR_PTR(error: -ENODEV);
106
107 return __fpga_bridge_get(dev, info);
108}
109EXPORT_SYMBOL_GPL(of_fpga_bridge_get);
110
111static int fpga_bridge_dev_match(struct device *dev, const void *data)
112{
113 return dev->parent == data;
114}
115
116/**
117 * fpga_bridge_get - get an exclusive reference to an fpga bridge
118 * @dev: parent device that fpga bridge was registered with
119 * @info: fpga image specific information
120 *
121 * Given a device, get an exclusive reference to an fpga bridge.
122 *
123 * Return: fpga bridge struct or IS_ERR() condition containing error code.
124 */
125struct fpga_bridge *fpga_bridge_get(struct device *dev,
126 struct fpga_image_info *info)
127{
128 struct device *bridge_dev;
129
130 bridge_dev = class_find_device(class: &fpga_bridge_class, NULL, data: dev,
131 match: fpga_bridge_dev_match);
132 if (!bridge_dev)
133 return ERR_PTR(error: -ENODEV);
134
135 return __fpga_bridge_get(dev: bridge_dev, info);
136}
137EXPORT_SYMBOL_GPL(fpga_bridge_get);
138
139/**
140 * fpga_bridge_put - release a reference to a bridge
141 *
142 * @bridge: FPGA bridge
143 */
144void fpga_bridge_put(struct fpga_bridge *bridge)
145{
146 dev_dbg(&bridge->dev, "put\n");
147
148 bridge->info = NULL;
149 module_put(module: bridge->dev.parent->driver->owner);
150 mutex_unlock(lock: &bridge->mutex);
151 put_device(dev: &bridge->dev);
152}
153EXPORT_SYMBOL_GPL(fpga_bridge_put);
154
155/**
156 * fpga_bridges_enable - enable bridges in a list
157 * @bridge_list: list of FPGA bridges
158 *
159 * Enable each bridge in the list. If list is empty, do nothing.
160 *
161 * Return: 0 for success or empty bridge list or an error code otherwise.
162 */
163int fpga_bridges_enable(struct list_head *bridge_list)
164{
165 struct fpga_bridge *bridge;
166 int ret;
167
168 list_for_each_entry(bridge, bridge_list, node) {
169 ret = fpga_bridge_enable(bridge);
170 if (ret)
171 return ret;
172 }
173
174 return 0;
175}
176EXPORT_SYMBOL_GPL(fpga_bridges_enable);
177
178/**
179 * fpga_bridges_disable - disable bridges in a list
180 *
181 * @bridge_list: list of FPGA bridges
182 *
183 * Disable each bridge in the list. If list is empty, do nothing.
184 *
185 * Return: 0 for success or empty bridge list or an error code otherwise.
186 */
187int fpga_bridges_disable(struct list_head *bridge_list)
188{
189 struct fpga_bridge *bridge;
190 int ret;
191
192 list_for_each_entry(bridge, bridge_list, node) {
193 ret = fpga_bridge_disable(bridge);
194 if (ret)
195 return ret;
196 }
197
198 return 0;
199}
200EXPORT_SYMBOL_GPL(fpga_bridges_disable);
201
202/**
203 * fpga_bridges_put - put bridges
204 *
205 * @bridge_list: list of FPGA bridges
206 *
207 * For each bridge in the list, put the bridge and remove it from the list.
208 * If list is empty, do nothing.
209 */
210void fpga_bridges_put(struct list_head *bridge_list)
211{
212 struct fpga_bridge *bridge, *next;
213 unsigned long flags;
214
215 list_for_each_entry_safe(bridge, next, bridge_list, node) {
216 fpga_bridge_put(bridge);
217
218 spin_lock_irqsave(&bridge_list_lock, flags);
219 list_del(entry: &bridge->node);
220 spin_unlock_irqrestore(lock: &bridge_list_lock, flags);
221 }
222}
223EXPORT_SYMBOL_GPL(fpga_bridges_put);
224
225/**
226 * of_fpga_bridge_get_to_list - get a bridge, add it to a list
227 *
228 * @np: node pointer of an FPGA bridge
229 * @info: fpga image specific information
230 * @bridge_list: list of FPGA bridges
231 *
232 * Get an exclusive reference to the bridge and it to the list.
233 *
234 * Return: 0 for success, error code from of_fpga_bridge_get() otherwise.
235 */
236int of_fpga_bridge_get_to_list(struct device_node *np,
237 struct fpga_image_info *info,
238 struct list_head *bridge_list)
239{
240 struct fpga_bridge *bridge;
241 unsigned long flags;
242
243 bridge = of_fpga_bridge_get(np, info);
244 if (IS_ERR(ptr: bridge))
245 return PTR_ERR(ptr: bridge);
246
247 spin_lock_irqsave(&bridge_list_lock, flags);
248 list_add(new: &bridge->node, head: bridge_list);
249 spin_unlock_irqrestore(lock: &bridge_list_lock, flags);
250
251 return 0;
252}
253EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);
254
255/**
256 * fpga_bridge_get_to_list - given device, get a bridge, add it to a list
257 *
258 * @dev: FPGA bridge device
259 * @info: fpga image specific information
260 * @bridge_list: list of FPGA bridges
261 *
262 * Get an exclusive reference to the bridge and it to the list.
263 *
264 * Return: 0 for success, error code from fpga_bridge_get() otherwise.
265 */
266int fpga_bridge_get_to_list(struct device *dev,
267 struct fpga_image_info *info,
268 struct list_head *bridge_list)
269{
270 struct fpga_bridge *bridge;
271 unsigned long flags;
272
273 bridge = fpga_bridge_get(dev, info);
274 if (IS_ERR(ptr: bridge))
275 return PTR_ERR(ptr: bridge);
276
277 spin_lock_irqsave(&bridge_list_lock, flags);
278 list_add(new: &bridge->node, head: bridge_list);
279 spin_unlock_irqrestore(lock: &bridge_list_lock, flags);
280
281 return 0;
282}
283EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
284
285static ssize_t name_show(struct device *dev,
286 struct device_attribute *attr, char *buf)
287{
288 struct fpga_bridge *bridge = to_fpga_bridge(dev);
289
290 return sprintf(buf, fmt: "%s\n", bridge->name);
291}
292
293static ssize_t state_show(struct device *dev,
294 struct device_attribute *attr, char *buf)
295{
296 struct fpga_bridge *bridge = to_fpga_bridge(dev);
297 int state = 1;
298
299 if (bridge->br_ops && bridge->br_ops->enable_show) {
300 state = bridge->br_ops->enable_show(bridge);
301 if (state < 0)
302 return state;
303 }
304
305 return sysfs_emit(buf, fmt: "%s\n", state ? "enabled" : "disabled");
306}
307
308static DEVICE_ATTR_RO(name);
309static DEVICE_ATTR_RO(state);
310
311static struct attribute *fpga_bridge_attrs[] = {
312 &dev_attr_name.attr,
313 &dev_attr_state.attr,
314 NULL,
315};
316ATTRIBUTE_GROUPS(fpga_bridge);
317
318/**
319 * fpga_bridge_register - create and register an FPGA Bridge device
320 * @parent: FPGA bridge device from pdev
321 * @name: FPGA bridge name
322 * @br_ops: pointer to structure of fpga bridge ops
323 * @priv: FPGA bridge private data
324 *
325 * Return: struct fpga_bridge pointer or ERR_PTR()
326 */
327struct fpga_bridge *
328fpga_bridge_register(struct device *parent, const char *name,
329 const struct fpga_bridge_ops *br_ops,
330 void *priv)
331{
332 struct fpga_bridge *bridge;
333 int id, ret;
334
335 if (!br_ops) {
336 dev_err(parent, "Attempt to register without fpga_bridge_ops\n");
337 return ERR_PTR(error: -EINVAL);
338 }
339
340 if (!name || !strlen(name)) {
341 dev_err(parent, "Attempt to register with no name!\n");
342 return ERR_PTR(error: -EINVAL);
343 }
344
345 bridge = kzalloc(size: sizeof(*bridge), GFP_KERNEL);
346 if (!bridge)
347 return ERR_PTR(error: -ENOMEM);
348
349 id = ida_alloc(ida: &fpga_bridge_ida, GFP_KERNEL);
350 if (id < 0) {
351 ret = id;
352 goto error_kfree;
353 }
354
355 mutex_init(&bridge->mutex);
356 INIT_LIST_HEAD(list: &bridge->node);
357
358 bridge->name = name;
359 bridge->br_ops = br_ops;
360 bridge->priv = priv;
361
362 bridge->dev.groups = br_ops->groups;
363 bridge->dev.class = &fpga_bridge_class;
364 bridge->dev.parent = parent;
365 bridge->dev.of_node = parent->of_node;
366 bridge->dev.id = id;
367
368 ret = dev_set_name(dev: &bridge->dev, name: "br%d", id);
369 if (ret)
370 goto error_device;
371
372 ret = device_register(dev: &bridge->dev);
373 if (ret) {
374 put_device(dev: &bridge->dev);
375 return ERR_PTR(error: ret);
376 }
377
378 of_platform_populate(root: bridge->dev.of_node, NULL, NULL, parent: &bridge->dev);
379
380 return bridge;
381
382error_device:
383 ida_free(&fpga_bridge_ida, id);
384error_kfree:
385 kfree(objp: bridge);
386
387 return ERR_PTR(error: ret);
388}
389EXPORT_SYMBOL_GPL(fpga_bridge_register);
390
391/**
392 * fpga_bridge_unregister - unregister an FPGA bridge
393 *
394 * @bridge: FPGA bridge struct
395 *
396 * This function is intended for use in an FPGA bridge driver's remove function.
397 */
398void fpga_bridge_unregister(struct fpga_bridge *bridge)
399{
400 /*
401 * If the low level driver provides a method for putting bridge into
402 * a desired state upon unregister, do it.
403 */
404 if (bridge->br_ops && bridge->br_ops->fpga_bridge_remove)
405 bridge->br_ops->fpga_bridge_remove(bridge);
406
407 device_unregister(dev: &bridge->dev);
408}
409EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
410
411static void fpga_bridge_dev_release(struct device *dev)
412{
413 struct fpga_bridge *bridge = to_fpga_bridge(dev);
414
415 ida_free(&fpga_bridge_ida, id: bridge->dev.id);
416 kfree(objp: bridge);
417}
418
419static const struct class fpga_bridge_class = {
420 .name = "fpga_bridge",
421 .dev_groups = fpga_bridge_groups,
422 .dev_release = fpga_bridge_dev_release,
423};
424
425static int __init fpga_bridge_dev_init(void)
426{
427 return class_register(class: &fpga_bridge_class);
428}
429
430static void __exit fpga_bridge_dev_exit(void)
431{
432 class_unregister(class: &fpga_bridge_class);
433 ida_destroy(ida: &fpga_bridge_ida);
434}
435
436MODULE_DESCRIPTION("FPGA Bridge Driver");
437MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
438MODULE_LICENSE("GPL v2");
439
440subsys_initcall(fpga_bridge_dev_init);
441module_exit(fpga_bridge_dev_exit);
442

source code of linux/drivers/fpga/fpga-bridge.c