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1/*
2 * FPGA Bridge Framework Driver
3 *
4 * Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
5 * Copyright (C) 2017 Intel Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19#include <linux/fpga/fpga-bridge.h>
20#include <linux/idr.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/of_platform.h>
24#include <linux/slab.h>
25#include <linux/spinlock.h>
26
27static DEFINE_IDA(fpga_bridge_ida);
28static struct class *fpga_bridge_class;
29
30/* Lock for adding/removing bridges to linked lists*/
31static spinlock_t bridge_list_lock;
32
33static int fpga_bridge_of_node_match(struct device *dev, const void *data)
34{
35 return dev->of_node == data;
36}
37
38/**
39 * fpga_bridge_enable - Enable transactions on the bridge
40 *
41 * @bridge: FPGA bridge
42 *
43 * Return: 0 for success, error code otherwise.
44 */
45int fpga_bridge_enable(struct fpga_bridge *bridge)
46{
47 dev_dbg(&bridge->dev, "enable\n");
48
49 if (bridge->br_ops && bridge->br_ops->enable_set)
50 return bridge->br_ops->enable_set(bridge, 1);
51
52 return 0;
53}
54EXPORT_SYMBOL_GPL(fpga_bridge_enable);
55
56/**
57 * fpga_bridge_disable - Disable transactions on the bridge
58 *
59 * @bridge: FPGA bridge
60 *
61 * Return: 0 for success, error code otherwise.
62 */
63int fpga_bridge_disable(struct fpga_bridge *bridge)
64{
65 dev_dbg(&bridge->dev, "disable\n");
66
67 if (bridge->br_ops && bridge->br_ops->enable_set)
68 return bridge->br_ops->enable_set(bridge, 0);
69
70 return 0;
71}
72EXPORT_SYMBOL_GPL(fpga_bridge_disable);
73
74static struct fpga_bridge *__fpga_bridge_get(struct device *dev,
75 struct fpga_image_info *info)
76{
77 struct fpga_bridge *bridge;
78 int ret = -ENODEV;
79
80 bridge = to_fpga_bridge(dev);
81
82 bridge->info = info;
83
84 if (!mutex_trylock(&bridge->mutex)) {
85 ret = -EBUSY;
86 goto err_dev;
87 }
88
89 if (!try_module_get(dev->parent->driver->owner))
90 goto err_ll_mod;
91
92 dev_dbg(&bridge->dev, "get\n");
93
94 return bridge;
95
96err_ll_mod:
97 mutex_unlock(&bridge->mutex);
98err_dev:
99 put_device(dev);
100 return ERR_PTR(ret);
101}
102
103/**
104 * of_fpga_bridge_get - get an exclusive reference to a fpga bridge
105 *
106 * @np: node pointer of a FPGA bridge
107 * @info: fpga image specific information
108 *
109 * Return fpga_bridge struct if successful.
110 * Return -EBUSY if someone already has a reference to the bridge.
111 * Return -ENODEV if @np is not a FPGA Bridge.
112 */
113struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
114 struct fpga_image_info *info)
115{
116 struct device *dev;
117
118 dev = class_find_device(fpga_bridge_class, NULL, np,
119 fpga_bridge_of_node_match);
120 if (!dev)
121 return ERR_PTR(-ENODEV);
122
123 return __fpga_bridge_get(dev, info);
124}
125EXPORT_SYMBOL_GPL(of_fpga_bridge_get);
126
127static int fpga_bridge_dev_match(struct device *dev, const void *data)
128{
129 return dev->parent == data;
130}
131
132/**
133 * fpga_bridge_get - get an exclusive reference to a fpga bridge
134 * @dev: parent device that fpga bridge was registered with
135 *
136 * Given a device, get an exclusive reference to a fpga bridge.
137 *
138 * Return: fpga manager struct or IS_ERR() condition containing error code.
139 */
140struct fpga_bridge *fpga_bridge_get(struct device *dev,
141 struct fpga_image_info *info)
142{
143 struct device *bridge_dev;
144
145 bridge_dev = class_find_device(fpga_bridge_class, NULL, dev,
146 fpga_bridge_dev_match);
147 if (!bridge_dev)
148 return ERR_PTR(-ENODEV);
149
150 return __fpga_bridge_get(bridge_dev, info);
151}
152EXPORT_SYMBOL_GPL(fpga_bridge_get);
153
154/**
155 * fpga_bridge_put - release a reference to a bridge
156 *
157 * @bridge: FPGA bridge
158 */
159void fpga_bridge_put(struct fpga_bridge *bridge)
160{
161 dev_dbg(&bridge->dev, "put\n");
162
163 bridge->info = NULL;
164 module_put(bridge->dev.parent->driver->owner);
165 mutex_unlock(&bridge->mutex);
166 put_device(&bridge->dev);
167}
168EXPORT_SYMBOL_GPL(fpga_bridge_put);
169
170/**
171 * fpga_bridges_enable - enable bridges in a list
172 * @bridge_list: list of FPGA bridges
173 *
174 * Enable each bridge in the list. If list is empty, do nothing.
175 *
176 * Return 0 for success or empty bridge list; return error code otherwise.
177 */
178int fpga_bridges_enable(struct list_head *bridge_list)
179{
180 struct fpga_bridge *bridge;
181 int ret;
182
183 list_for_each_entry(bridge, bridge_list, node) {
184 ret = fpga_bridge_enable(bridge);
185 if (ret)
186 return ret;
187 }
188
189 return 0;
190}
191EXPORT_SYMBOL_GPL(fpga_bridges_enable);
192
193/**
194 * fpga_bridges_disable - disable bridges in a list
195 *
196 * @bridge_list: list of FPGA bridges
197 *
198 * Disable each bridge in the list. If list is empty, do nothing.
199 *
200 * Return 0 for success or empty bridge list; return error code otherwise.
201 */
202int fpga_bridges_disable(struct list_head *bridge_list)
203{
204 struct fpga_bridge *bridge;
205 int ret;
206
207 list_for_each_entry(bridge, bridge_list, node) {
208 ret = fpga_bridge_disable(bridge);
209 if (ret)
210 return ret;
211 }
212
213 return 0;
214}
215EXPORT_SYMBOL_GPL(fpga_bridges_disable);
216
217/**
218 * fpga_bridges_put - put bridges
219 *
220 * @bridge_list: list of FPGA bridges
221 *
222 * For each bridge in the list, put the bridge and remove it from the list.
223 * If list is empty, do nothing.
224 */
225void fpga_bridges_put(struct list_head *bridge_list)
226{
227 struct fpga_bridge *bridge, *next;
228 unsigned long flags;
229
230 list_for_each_entry_safe(bridge, next, bridge_list, node) {
231 fpga_bridge_put(bridge);
232
233 spin_lock_irqsave(&bridge_list_lock, flags);
234 list_del(&bridge->node);
235 spin_unlock_irqrestore(&bridge_list_lock, flags);
236 }
237}
238EXPORT_SYMBOL_GPL(fpga_bridges_put);
239
240/**
241 * of_fpga_bridge_get_to_list - get a bridge, add it to a list
242 *
243 * @np: node pointer of a FPGA bridge
244 * @info: fpga image specific information
245 * @bridge_list: list of FPGA bridges
246 *
247 * Get an exclusive reference to the bridge and and it to the list.
248 *
249 * Return 0 for success, error code from of_fpga_bridge_get() othewise.
250 */
251int of_fpga_bridge_get_to_list(struct device_node *np,
252 struct fpga_image_info *info,
253 struct list_head *bridge_list)
254{
255 struct fpga_bridge *bridge;
256 unsigned long flags;
257
258 bridge = of_fpga_bridge_get(np, info);
259 if (IS_ERR(bridge))
260 return PTR_ERR(bridge);
261
262 spin_lock_irqsave(&bridge_list_lock, flags);
263 list_add(&bridge->node, bridge_list);
264 spin_unlock_irqrestore(&bridge_list_lock, flags);
265
266 return 0;
267}
268EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);
269
270/**
271 * fpga_bridge_get_to_list - given device, get a bridge, add it to a list
272 *
273 * @dev: FPGA bridge device
274 * @info: fpga image specific information
275 * @bridge_list: list of FPGA bridges
276 *
277 * Get an exclusive reference to the bridge and and it to the list.
278 *
279 * Return 0 for success, error code from fpga_bridge_get() othewise.
280 */
281int fpga_bridge_get_to_list(struct device *dev,
282 struct fpga_image_info *info,
283 struct list_head *bridge_list)
284{
285 struct fpga_bridge *bridge;
286 unsigned long flags;
287
288 bridge = fpga_bridge_get(dev, info);
289 if (IS_ERR(bridge))
290 return PTR_ERR(bridge);
291
292 spin_lock_irqsave(&bridge_list_lock, flags);
293 list_add(&bridge->node, bridge_list);
294 spin_unlock_irqrestore(&bridge_list_lock, flags);
295
296 return 0;
297}
298EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
299
300static ssize_t name_show(struct device *dev,
301 struct device_attribute *attr, char *buf)
302{
303 struct fpga_bridge *bridge = to_fpga_bridge(dev);
304
305 return sprintf(buf, "%s\n", bridge->name);
306}
307
308static ssize_t state_show(struct device *dev,
309 struct device_attribute *attr, char *buf)
310{
311 struct fpga_bridge *bridge = to_fpga_bridge(dev);
312 int enable = 1;
313
314 if (bridge->br_ops && bridge->br_ops->enable_show)
315 enable = bridge->br_ops->enable_show(bridge);
316
317 return sprintf(buf, "%s\n", enable ? "enabled" : "disabled");
318}
319
320static DEVICE_ATTR_RO(name);
321static DEVICE_ATTR_RO(state);
322
323static struct attribute *fpga_bridge_attrs[] = {
324 &dev_attr_name.attr,
325 &dev_attr_state.attr,
326 NULL,
327};
328ATTRIBUTE_GROUPS(fpga_bridge);
329
330/**
331 * fpga_bridge_register - register a fpga bridge driver
332 * @dev: FPGA bridge device from pdev
333 * @name: FPGA bridge name
334 * @br_ops: pointer to structure of fpga bridge ops
335 * @priv: FPGA bridge private data
336 *
337 * Return: 0 for success, error code otherwise.
338 */
339int fpga_bridge_register(struct device *dev, const char *name,
340 const struct fpga_bridge_ops *br_ops, void *priv)
341{
342 struct fpga_bridge *bridge;
343 int id, ret = 0;
344
345 if (!name || !strlen(name)) {
346 dev_err(dev, "Attempt to register with no name!\n");
347 return -EINVAL;
348 }
349
350 bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
351 if (!bridge)
352 return -ENOMEM;
353
354 id = ida_simple_get(&fpga_bridge_ida, 0, 0, GFP_KERNEL);
355 if (id < 0) {
356 ret = id;
357 goto error_kfree;
358 }
359
360 mutex_init(&bridge->mutex);
361 INIT_LIST_HEAD(&bridge->node);
362
363 bridge->name = name;
364 bridge->br_ops = br_ops;
365 bridge->priv = priv;
366
367 device_initialize(&bridge->dev);
368 bridge->dev.groups = br_ops->groups;
369 bridge->dev.class = fpga_bridge_class;
370 bridge->dev.parent = dev;
371 bridge->dev.of_node = dev->of_node;
372 bridge->dev.id = id;
373 dev_set_drvdata(dev, bridge);
374
375 ret = dev_set_name(&bridge->dev, "br%d", id);
376 if (ret)
377 goto error_device;
378
379 ret = device_add(&bridge->dev);
380 if (ret)
381 goto error_device;
382
383 of_platform_populate(dev->of_node, NULL, NULL, dev);
384
385 dev_info(bridge->dev.parent, "fpga bridge [%s] registered\n",
386 bridge->name);
387
388 return 0;
389
390error_device:
391 ida_simple_remove(&fpga_bridge_ida, id);
392error_kfree:
393 kfree(bridge);
394
395 return ret;
396}
397EXPORT_SYMBOL_GPL(fpga_bridge_register);
398
399/**
400 * fpga_bridge_unregister - unregister a fpga bridge driver
401 * @dev: FPGA bridge device from pdev
402 */
403void fpga_bridge_unregister(struct device *dev)
404{
405 struct fpga_bridge *bridge = dev_get_drvdata(dev);
406
407 /*
408 * If the low level driver provides a method for putting bridge into
409 * a desired state upon unregister, do it.
410 */
411 if (bridge->br_ops && bridge->br_ops->fpga_bridge_remove)
412 bridge->br_ops->fpga_bridge_remove(bridge);
413
414 device_unregister(&bridge->dev);
415}
416EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
417
418static void fpga_bridge_dev_release(struct device *dev)
419{
420 struct fpga_bridge *bridge = to_fpga_bridge(dev);
421
422 ida_simple_remove(&fpga_bridge_ida, bridge->dev.id);
423 kfree(bridge);
424}
425
426static int __init fpga_bridge_dev_init(void)
427{
428 spin_lock_init(&bridge_list_lock);
429
430 fpga_bridge_class = class_create(THIS_MODULE, "fpga_bridge");
431 if (IS_ERR(fpga_bridge_class))
432 return PTR_ERR(fpga_bridge_class);
433
434 fpga_bridge_class->dev_groups = fpga_bridge_groups;
435 fpga_bridge_class->dev_release = fpga_bridge_dev_release;
436
437 return 0;
438}
439
440static void __exit fpga_bridge_dev_exit(void)
441{
442 class_destroy(fpga_bridge_class);
443 ida_destroy(&fpga_bridge_ida);
444}
445
446MODULE_DESCRIPTION("FPGA Bridge Driver");
447MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
448MODULE_LICENSE("GPL v2");
449
450subsys_initcall(fpga_bridge_dev_init);
451module_exit(fpga_bridge_dev_exit);