summaryrefslogtreecommitdiffstats
path: root/drivers/fpga/fpga-bridge.c
blob: 5cd40acab5bfb85f52302ea244c2906af1213f1f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
// SPDX-License-Identifier: GPL-2.0
/*
 * FPGA Bridge Framework Driver
 *
 *  Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
 *  Copyright (C) 2017 Intel Corporation
 */
#include <linux/fpga/fpga-bridge.h>
#include <linux/idr.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

static DEFINE_IDA(fpga_bridge_ida);
static struct class *fpga_bridge_class;

/* Lock for adding/removing bridges to linked lists*/
static DEFINE_SPINLOCK(bridge_list_lock);

/**
 * fpga_bridge_enable - Enable transactions on the bridge
 *
 * @bridge: FPGA bridge
 *
 * Return: 0 for success, error code otherwise.
 */
int fpga_bridge_enable(struct fpga_bridge *bridge)
{
	dev_dbg(&bridge->dev, "enable\n");

	if (bridge->br_ops && bridge->br_ops->enable_set)
		return bridge->br_ops->enable_set(bridge, 1);

	return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridge_enable);

/**
 * fpga_bridge_disable - Disable transactions on the bridge
 *
 * @bridge: FPGA bridge
 *
 * Return: 0 for success, error code otherwise.
 */
int fpga_bridge_disable(struct fpga_bridge *bridge)
{
	dev_dbg(&bridge->dev, "disable\n");

	if (bridge->br_ops && bridge->br_ops->enable_set)
		return bridge->br_ops->enable_set(bridge, 0);

	return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridge_disable);

static struct fpga_bridge *__fpga_bridge_get(struct device *dev,
					     struct fpga_image_info *info)
{
	struct fpga_bridge *bridge;
	int ret = -ENODEV;

	bridge = to_fpga_bridge(dev);

	bridge->info = info;

	if (!mutex_trylock(&bridge->mutex)) {
		ret = -EBUSY;
		goto err_dev;
	}

	if (!try_module_get(dev->parent->driver->owner))
		goto err_ll_mod;

	dev_dbg(&bridge->dev, "get\n");

	return bridge;

err_ll_mod:
	mutex_unlock(&bridge->mutex);
err_dev:
	put_device(dev);
	return ERR_PTR(ret);
}

/**
 * of_fpga_bridge_get - get an exclusive reference to an fpga bridge
 *
 * @np: node pointer of an FPGA bridge
 * @info: fpga image specific information
 *
 * Return fpga_bridge struct if successful.
 * Return -EBUSY if someone already has a reference to the bridge.
 * Return -ENODEV if @np is not an FPGA Bridge.
 */
struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
				       struct fpga_image_info *info)
{
	struct device *dev;

	dev = class_find_device_by_of_node(fpga_bridge_class, np);
	if (!dev)
		return ERR_PTR(-ENODEV);

	return __fpga_bridge_get(dev, info);
}
EXPORT_SYMBOL_GPL(of_fpga_bridge_get);

static int fpga_bridge_dev_match(struct device *dev, const void *data)
{
	return dev->parent == data;
}

/**
 * fpga_bridge_get - get an exclusive reference to an fpga bridge
 * @dev:	parent device that fpga bridge was registered with
 * @info:	fpga manager info
 *
 * Given a device, get an exclusive reference to an fpga bridge.
 *
 * Return: fpga bridge struct or IS_ERR() condition containing error code.
 */
struct fpga_bridge *fpga_bridge_get(struct device *dev,
				    struct fpga_image_info *info)
{
	struct device *bridge_dev;

	bridge_dev = class_find_device(fpga_bridge_class, NULL, dev,
				       fpga_bridge_dev_match);
	if (!bridge_dev)
		return ERR_PTR(-ENODEV);

	return __fpga_bridge_get(bridge_dev, info);
}
EXPORT_SYMBOL_GPL(fpga_bridge_get);

/**
 * fpga_bridge_put - release a reference to a bridge
 *
 * @bridge: FPGA bridge
 */
void fpga_bridge_put(struct fpga_bridge *bridge)
{
	dev_dbg(&bridge->dev, "put\n");

	bridge->info = NULL;
	module_put(bridge->dev.parent->driver->owner);
	mutex_unlock(&bridge->mutex);
	put_device(&bridge->dev);
}
EXPORT_SYMBOL_GPL(fpga_bridge_put);

/**
 * fpga_bridges_enable - enable bridges in a list
 * @bridge_list: list of FPGA bridges
 *
 * Enable each bridge in the list.  If list is empty, do nothing.
 *
 * Return 0 for success or empty bridge list; return error code otherwise.
 */
int fpga_bridges_enable(struct list_head *bridge_list)
{
	struct fpga_bridge *bridge;
	int ret;

	list_for_each_entry(bridge, bridge_list, node) {
		ret = fpga_bridge_enable(bridge);
		if (ret)
			return ret;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridges_enable);

/**
 * fpga_bridges_disable - disable bridges in a list
 *
 * @bridge_list: list of FPGA bridges
 *
 * Disable each bridge in the list.  If list is empty, do nothing.
 *
 * Return 0 for success or empty bridge list; return error code otherwise.
 */
int fpga_bridges_disable(struct list_head *bridge_list)
{
	struct fpga_bridge *bridge;
	int ret;

	list_for_each_entry(bridge, bridge_list, node) {
		ret = fpga_bridge_disable(bridge);
		if (ret)
			return ret;
	}

	return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridges_disable);

/**
 * fpga_bridges_put - put bridges
 *
 * @bridge_list: list of FPGA bridges
 *
 * For each bridge in the list, put the bridge and remove it from the list.
 * If list is empty, do nothing.
 */
void fpga_bridges_put(struct list_head *bridge_list)
{
	struct fpga_bridge *bridge, *next;
	unsigned long flags;

	list_for_each_entry_safe(bridge, next, bridge_list, node) {
		fpga_bridge_put(bridge);

		spin_lock_irqsave(&bridge_list_lock, flags);
		list_del(&bridge->node);
		spin_unlock_irqrestore(&bridge_list_lock, flags);
	}
}
EXPORT_SYMBOL_GPL(fpga_bridges_put);

/**
 * of_fpga_bridge_get_to_list - get a bridge, add it to a list
 *
 * @np: node pointer of an FPGA bridge
 * @info: fpga image specific information
 * @bridge_list: list of FPGA bridges
 *
 * Get an exclusive reference to the bridge and it to the list.
 *
 * Return 0 for success, error code from of_fpga_bridge_get() otherwise.
 */
int of_fpga_bridge_get_to_list(struct device_node *np,
			       struct fpga_image_info *info,
			       struct list_head *bridge_list)
{
	struct fpga_bridge *bridge;
	unsigned long flags;

	bridge = of_fpga_bridge_get(np, info);
	if (IS_ERR(bridge))
		return PTR_ERR(bridge);

	spin_lock_irqsave(&bridge_list_lock, flags);
	list_add(&bridge->node, bridge_list);
	spin_unlock_irqrestore(&bridge_list_lock, flags);

	return 0;
}
EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);

/**
 * fpga_bridge_get_to_list - given device, get a bridge, add it to a list
 *
 * @dev: FPGA bridge device
 * @info: fpga image specific information
 * @bridge_list: list of FPGA bridges
 *
 * Get an exclusive reference to the bridge and it to the list.
 *
 * Return 0 for success, error code from fpga_bridge_get() otherwise.
 */
int fpga_bridge_get_to_list(struct device *dev,
			    struct fpga_image_info *info,
			    struct list_head *bridge_list)
{
	struct fpga_bridge *bridge;
	unsigned long flags;

	bridge = fpga_bridge_get(dev, info);
	if (IS_ERR(bridge))
		return PTR_ERR(bridge);

	spin_lock_irqsave(&bridge_list_lock, flags);
	list_add(&bridge->node, bridge_list);
	spin_unlock_irqrestore(&bridge_list_lock, flags);

	return 0;
}
EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);

static ssize_t name_show(struct device *dev,
			 struct device_attribute *attr, char *buf)
{
	struct fpga_bridge *bridge = to_fpga_bridge(dev);

	return sprintf(buf, "%s\n", bridge->name);
}

static ssize_t state_show(struct device *dev,
			  struct device_attribute *attr, char *buf)
{
	struct fpga_bridge *bridge = to_fpga_bridge(dev);
	int state = 1;

	if (bridge->br_ops && bridge->br_ops->enable_show) {
		state = bridge->br_ops->enable_show(bridge);
		if (state < 0)
			return state;
	}

	return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
}

static DEVICE_ATTR_RO(name);
static DEVICE_ATTR_RO(state);

static struct attribute *fpga_bridge_attrs[] = {
	&dev_attr_name.attr,
	&dev_attr_state.attr,
	NULL,
};
ATTRIBUTE_GROUPS(fpga_bridge);

/**
 * fpga_bridge_register - create and register an FPGA Bridge device
 * @parent:	FPGA bridge device from pdev
 * @name:	FPGA bridge name
 * @br_ops:	pointer to structure of fpga bridge ops
 * @priv:	FPGA bridge private data
 *
 * Return: struct fpga_bridge pointer or ERR_PTR()
 */
struct fpga_bridge *
fpga_bridge_register(struct device *parent, const char *name,
		     const struct fpga_bridge_ops *br_ops,
		     void *priv)
{
	struct fpga_bridge *bridge;
	int id, ret;

	if (!br_ops) {
		dev_err(parent, "Attempt to register without fpga_bridge_ops\n");
		return ERR_PTR(-EINVAL);
	}

	if (!name || !strlen(name)) {
		dev_err(parent, "Attempt to register with no name!\n");
		return ERR_PTR(-EINVAL);
	}

	bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
	if (!bridge)
		return ERR_PTR(-ENOMEM);

	id = ida_alloc(&fpga_bridge_ida, GFP_KERNEL);
	if (id < 0) {
		ret = id;
		goto error_kfree;
	}

	mutex_init(&bridge->mutex);
	INIT_LIST_HEAD(&bridge->node);

	bridge->name = name;
	bridge->br_ops = br_ops;
	bridge->priv = priv;

	bridge->dev.groups = br_ops->groups;
	bridge->dev.class = fpga_bridge_class;
	bridge->dev.parent = parent;
	bridge->dev.of_node = parent->of_node;
	bridge->dev.id = id;
	of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev);

	ret = dev_set_name(&bridge->dev, "br%d", id);
	if (ret)
		goto error_device;

	ret = device_register(&bridge->dev);
	if (ret) {
		put_device(&bridge->dev);
		return ERR_PTR(ret);
	}

	return bridge;

error_device:
	ida_free(&fpga_bridge_ida, id);
error_kfree:
	kfree(bridge);

	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(fpga_bridge_register);

/**
 * fpga_bridge_unregister - unregister an FPGA bridge
 *
 * @bridge: FPGA bridge struct
 *
 * This function is intended for use in an FPGA bridge driver's remove function.
 */
void fpga_bridge_unregister(struct fpga_bridge *bridge)
{
	/*
	 * If the low level driver provides a method for putting bridge into
	 * a desired state upon unregister, do it.
	 */
	if (bridge->br_ops && bridge->br_ops->fpga_bridge_remove)
		bridge->br_ops->fpga_bridge_remove(bridge);

	device_unregister(&bridge->dev);
}
EXPORT_SYMBOL_GPL(fpga_bridge_unregister);

static void fpga_bridge_dev_release(struct device *dev)
{
	struct fpga_bridge *bridge = to_fpga_bridge(dev);

	ida_free(&fpga_bridge_ida, bridge->dev.id);
	kfree(bridge);
}

static int __init fpga_bridge_dev_init(void)
{
	fpga_bridge_class = class_create(THIS_MODULE, "fpga_bridge");
	if (IS_ERR(fpga_bridge_class))
		return PTR_ERR(fpga_bridge_class);

	fpga_bridge_class->dev_groups = fpga_bridge_groups;
	fpga_bridge_class->dev_release = fpga_bridge_dev_release;

	return 0;
}

static void __exit fpga_bridge_dev_exit(void)
{
	class_destroy(fpga_bridge_class);
	ida_destroy(&fpga_bridge_ida);
}

MODULE_DESCRIPTION("FPGA Bridge Driver");
MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
MODULE_LICENSE("GPL v2");

subsys_initcall(fpga_bridge_dev_init);
module_exit(fpga_bridge_dev_exit);