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