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->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->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 *bridge_dev,
 59					     struct fpga_image_info *info)
 60{
 61	struct fpga_bridge *bridge;
 62
 63	bridge = to_fpga_bridge(bridge_dev);
 64
 65	bridge->info = info;
 66
 67	if (!mutex_trylock(&bridge->mutex))
 68		return ERR_PTR(-EBUSY);
 69
 70	if (!try_module_get(bridge->br_ops_owner)) {
 71		mutex_unlock(&bridge->mutex);
 72		return ERR_PTR(-ENODEV);
 73	}
 74
 75	dev_dbg(&bridge->dev, "get\n");
 76
 77	return bridge;
 78}
 79
 80/**
 81 * of_fpga_bridge_get - get an exclusive reference to an fpga bridge
 82 *
 83 * @np: node pointer of an FPGA bridge.
 84 * @info: fpga image specific information.
 85 *
 86 * Return:
 87 * * fpga_bridge struct pointer if successful.
 88 * * -EBUSY if someone already has a reference to the bridge.
 89 * * -ENODEV if @np is not an FPGA Bridge or can't take parent driver refcount.
 90 */
 91struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
 92				       struct fpga_image_info *info)
 93{
 94	struct fpga_bridge *bridge;
 95	struct device *bridge_dev;
 96
 97	bridge_dev = class_find_device_by_of_node(&fpga_bridge_class, np);
 98	if (!bridge_dev)
 99		return ERR_PTR(-ENODEV);
100
101	bridge = __fpga_bridge_get(bridge_dev, info);
102	if (IS_ERR(bridge))
103		put_device(bridge_dev);
104
105	return bridge;
106}
107EXPORT_SYMBOL_GPL(of_fpga_bridge_get);
108
109static int fpga_bridge_dev_match(struct device *dev, const void *data)
110{
111	return dev->parent == data;
112}
113
114/**
115 * fpga_bridge_get - get an exclusive reference to an fpga bridge
116 * @dev:	parent device that fpga bridge was registered with
117 * @info:	fpga image specific information
118 *
119 * Given a device, get an exclusive reference to an fpga bridge.
120 *
121 * Return: fpga bridge struct or IS_ERR() condition containing error code.
122 */
123struct fpga_bridge *fpga_bridge_get(struct device *dev,
124				    struct fpga_image_info *info)
125{
126	struct fpga_bridge *bridge;
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	bridge = __fpga_bridge_get(bridge_dev, info);
135	if (IS_ERR(bridge))
136		put_device(bridge_dev);
137
138	return bridge;
139}
140EXPORT_SYMBOL_GPL(fpga_bridge_get);
141
142/**
143 * fpga_bridge_put - release a reference to a bridge
144 *
145 * @bridge: FPGA bridge
146 */
147void fpga_bridge_put(struct fpga_bridge *bridge)
148{
149	dev_dbg(&bridge->dev, "put\n");
150
151	bridge->info = NULL;
152	module_put(bridge->br_ops_owner);
153	mutex_unlock(&bridge->mutex);
154	put_device(&bridge->dev);
155}
156EXPORT_SYMBOL_GPL(fpga_bridge_put);
157
158/**
159 * fpga_bridges_enable - enable bridges in a list
160 * @bridge_list: list of FPGA bridges
161 *
162 * Enable each bridge in the list. If list is empty, do nothing.
163 *
164 * Return: 0 for success or empty bridge list or an error code otherwise.
165 */
166int fpga_bridges_enable(struct list_head *bridge_list)
167{
168	struct fpga_bridge *bridge;
169	int ret;
170
171	list_for_each_entry(bridge, bridge_list, node) {
172		ret = fpga_bridge_enable(bridge);
173		if (ret)
174			return ret;
175	}
176
177	return 0;
178}
179EXPORT_SYMBOL_GPL(fpga_bridges_enable);
180
181/**
182 * fpga_bridges_disable - disable bridges in a list
183 *
184 * @bridge_list: list of FPGA bridges
185 *
186 * Disable each bridge in the list. If list is empty, do nothing.
187 *
188 * Return: 0 for success or empty bridge list or an error code otherwise.
189 */
190int fpga_bridges_disable(struct list_head *bridge_list)
191{
192	struct fpga_bridge *bridge;
193	int ret;
194
195	list_for_each_entry(bridge, bridge_list, node) {
196		ret = fpga_bridge_disable(bridge);
197		if (ret)
198			return ret;
199	}
200
201	return 0;
202}
203EXPORT_SYMBOL_GPL(fpga_bridges_disable);
204
205/**
206 * fpga_bridges_put - put bridges
207 *
208 * @bridge_list: list of FPGA bridges
209 *
210 * For each bridge in the list, put the bridge and remove it from the list.
211 * If list is empty, do nothing.
212 */
213void fpga_bridges_put(struct list_head *bridge_list)
214{
215	struct fpga_bridge *bridge, *next;
216	unsigned long flags;
217
218	list_for_each_entry_safe(bridge, next, bridge_list, node) {
219		fpga_bridge_put(bridge);
220
221		spin_lock_irqsave(&bridge_list_lock, flags);
222		list_del(&bridge->node);
223		spin_unlock_irqrestore(&bridge_list_lock, flags);
224	}
225}
226EXPORT_SYMBOL_GPL(fpga_bridges_put);
227
228/**
229 * of_fpga_bridge_get_to_list - get a bridge, add it to a list
230 *
231 * @np: node pointer of an FPGA bridge
232 * @info: fpga image specific information
233 * @bridge_list: list of FPGA bridges
234 *
235 * Get an exclusive reference to the bridge and it to the list.
236 *
237 * Return: 0 for success, error code from of_fpga_bridge_get() otherwise.
238 */
239int of_fpga_bridge_get_to_list(struct device_node *np,
240			       struct fpga_image_info *info,
241			       struct list_head *bridge_list)
242{
243	struct fpga_bridge *bridge;
244	unsigned long flags;
245
246	bridge = of_fpga_bridge_get(np, info);
247	if (IS_ERR(bridge))
248		return PTR_ERR(bridge);
249
250	spin_lock_irqsave(&bridge_list_lock, flags);
251	list_add(&bridge->node, bridge_list);
252	spin_unlock_irqrestore(&bridge_list_lock, flags);
253
254	return 0;
255}
256EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);
257
258/**
259 * fpga_bridge_get_to_list - given device, get a bridge, add it to a list
260 *
261 * @dev: FPGA bridge device
262 * @info: fpga image specific information
263 * @bridge_list: list of FPGA bridges
264 *
265 * Get an exclusive reference to the bridge and it to the list.
266 *
267 * Return: 0 for success, error code from fpga_bridge_get() otherwise.
268 */
269int fpga_bridge_get_to_list(struct device *dev,
270			    struct fpga_image_info *info,
271			    struct list_head *bridge_list)
272{
273	struct fpga_bridge *bridge;
274	unsigned long flags;
275
276	bridge = fpga_bridge_get(dev, info);
277	if (IS_ERR(bridge))
278		return PTR_ERR(bridge);
279
280	spin_lock_irqsave(&bridge_list_lock, flags);
281	list_add(&bridge->node, bridge_list);
282	spin_unlock_irqrestore(&bridge_list_lock, flags);
283
284	return 0;
285}
286EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
287
288static ssize_t name_show(struct device *dev,
289			 struct device_attribute *attr, char *buf)
290{
291	struct fpga_bridge *bridge = to_fpga_bridge(dev);
292
293	return sprintf(buf, "%s\n", bridge->name);
294}
295
296static ssize_t state_show(struct device *dev,
297			  struct device_attribute *attr, char *buf)
298{
299	struct fpga_bridge *bridge = to_fpga_bridge(dev);
300	int state = 1;
301
302	if (bridge->br_ops->enable_show) {
303		state = bridge->br_ops->enable_show(bridge);
304		if (state < 0)
305			return state;
306	}
307
308	return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
309}
310
311static DEVICE_ATTR_RO(name);
312static DEVICE_ATTR_RO(state);
313
314static struct attribute *fpga_bridge_attrs[] = {
315	&dev_attr_name.attr,
316	&dev_attr_state.attr,
317	NULL,
318};
319ATTRIBUTE_GROUPS(fpga_bridge);
320
321/**
322 * __fpga_bridge_register - create and register an FPGA Bridge device
323 * @parent:	FPGA bridge device from pdev
324 * @name:	FPGA bridge name
325 * @br_ops:	pointer to structure of fpga bridge ops
326 * @priv:	FPGA bridge private data
327 * @owner:	owner module containing the br_ops
328 *
329 * Return: struct fpga_bridge pointer or ERR_PTR()
330 */
331struct fpga_bridge *
332__fpga_bridge_register(struct device *parent, const char *name,
333		       const struct fpga_bridge_ops *br_ops,
334		       void *priv, struct module *owner)
335{
336	struct fpga_bridge *bridge;
337	int id, ret;
338
339	if (!br_ops) {
340		dev_err(parent, "Attempt to register without fpga_bridge_ops\n");
341		return ERR_PTR(-EINVAL);
342	}
343
344	if (!name || !strlen(name)) {
345		dev_err(parent, "Attempt to register with no name!\n");
346		return ERR_PTR(-EINVAL);
347	}
348
349	bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
350	if (!bridge)
351		return ERR_PTR(-ENOMEM);
352
353	id = ida_alloc(&fpga_bridge_ida, GFP_KERNEL);
354	if (id < 0) {
355		ret = id;
356		goto error_kfree;
357	}
358
359	mutex_init(&bridge->mutex);
360	INIT_LIST_HEAD(&bridge->node);
361
362	bridge->name = name;
363	bridge->br_ops = br_ops;
364	bridge->br_ops_owner = owner;
365	bridge->priv = priv;
366
367	bridge->dev.groups = br_ops->groups;
368	bridge->dev.class = &fpga_bridge_class;
369	bridge->dev.parent = parent;
370	bridge->dev.of_node = parent->of_node;
371	bridge->dev.id = id;
372
373	ret = dev_set_name(&bridge->dev, "br%d", id);
374	if (ret)
375		goto error_device;
376
377	ret = device_register(&bridge->dev);
378	if (ret) {
379		put_device(&bridge->dev);
380		return ERR_PTR(ret);
381	}
382
383	of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev);
384
385	return bridge;
386
387error_device:
388	ida_free(&fpga_bridge_ida, id);
389error_kfree:
390	kfree(bridge);
391
392	return ERR_PTR(ret);
393}
394EXPORT_SYMBOL_GPL(__fpga_bridge_register);
395
396/**
397 * fpga_bridge_unregister - unregister an FPGA bridge
398 *
399 * @bridge: FPGA bridge struct
400 *
401 * This function is intended for use in an FPGA bridge driver's remove function.
402 */
403void fpga_bridge_unregister(struct fpga_bridge *bridge)
404{
405	/*
406	 * If the low level driver provides a method for putting bridge into
407	 * a desired state upon unregister, do it.
408	 */
409	if (bridge->br_ops->fpga_bridge_remove)
410		bridge->br_ops->fpga_bridge_remove(bridge);
411
412	device_unregister(&bridge->dev);
413}
414EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
415
416static void fpga_bridge_dev_release(struct device *dev)
417{
418	struct fpga_bridge *bridge = to_fpga_bridge(dev);
419
420	ida_free(&fpga_bridge_ida, bridge->dev.id);
421	kfree(bridge);
422}
423
424static const struct class fpga_bridge_class = {
425	.name = "fpga_bridge",
426	.dev_groups = fpga_bridge_groups,
427	.dev_release = fpga_bridge_dev_release,
428};
429
430static int __init fpga_bridge_dev_init(void)
431{
432	return class_register(&fpga_bridge_class);
433}
434
435static void __exit fpga_bridge_dev_exit(void)
436{
437	class_unregister(&fpga_bridge_class);
438	ida_destroy(&fpga_bridge_ida);
439}
440
441MODULE_DESCRIPTION("FPGA Bridge Driver");
442MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
443MODULE_LICENSE("GPL v2");
444
445subsys_initcall(fpga_bridge_dev_init);
446module_exit(fpga_bridge_dev_exit);