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