1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * FPGA Region - Support for FPGA programming under Linux
  4 *
  5 *  Copyright (C) 2013-2016 Altera Corporation
  6 *  Copyright (C) 2017 Intel Corporation
  7 */
  8#include <linux/fpga/fpga-bridge.h>
  9#include <linux/fpga/fpga-mgr.h>
 10#include <linux/fpga/fpga-region.h>
 11#include <linux/idr.h>
 12#include <linux/kernel.h>
 13#include <linux/list.h>
 14#include <linux/module.h>
 15#include <linux/slab.h>
 16#include <linux/spinlock.h>
 17
 18static DEFINE_IDA(fpga_region_ida);
 19static struct class *fpga_region_class;
 20
 21struct fpga_region *
 22fpga_region_class_find(struct device *start, const void *data,
 23		       int (*match)(struct device *, const void *))
 24{
 25	struct device *dev;
 26
 27	dev = class_find_device(fpga_region_class, start, data, match);
 28	if (!dev)
 29		return NULL;
 30
 31	return to_fpga_region(dev);
 32}
 33EXPORT_SYMBOL_GPL(fpga_region_class_find);
 34
 35/**
 36 * fpga_region_get - get an exclusive reference to an fpga region
 37 * @region: FPGA Region struct
 38 *
 39 * Caller should call fpga_region_put() when done with region.
 40 *
 41 * Return fpga_region struct if successful.
 42 * Return -EBUSY if someone already has a reference to the region.
 43 * Return -ENODEV if @np is not an FPGA Region.
 44 */
 45static struct fpga_region *fpga_region_get(struct fpga_region *region)
 46{
 47	struct device *dev = &region->dev;
 48
 49	if (!mutex_trylock(&region->mutex)) {
 50		dev_dbg(dev, "%s: FPGA Region already in use\n", __func__);
 51		return ERR_PTR(-EBUSY);
 52	}
 53
 54	get_device(dev);
 55	if (!try_module_get(dev->parent->driver->owner)) {
 56		put_device(dev);
 57		mutex_unlock(&region->mutex);
 58		return ERR_PTR(-ENODEV);
 59	}
 60
 61	dev_dbg(dev, "get\n");
 62
 63	return region;
 64}
 65
 66/**
 67 * fpga_region_put - release a reference to a region
 68 *
 69 * @region: FPGA region
 70 */
 71static void fpga_region_put(struct fpga_region *region)
 72{
 73	struct device *dev = &region->dev;
 74
 75	dev_dbg(dev, "put\n");
 76
 77	module_put(dev->parent->driver->owner);
 78	put_device(dev);
 79	mutex_unlock(&region->mutex);
 80}
 81
 82/**
 83 * fpga_region_program_fpga - program FPGA
 84 *
 85 * @region: FPGA region
 86 *
 87 * Program an FPGA using fpga image info (region->info).
 88 * If the region has a get_bridges function, the exclusive reference for the
 89 * bridges will be held if programming succeeds.  This is intended to prevent
 90 * reprogramming the region until the caller considers it safe to do so.
 91 * The caller will need to call fpga_bridges_put() before attempting to
 92 * reprogram the region.
 93 *
 94 * Return 0 for success or negative error code.
 95 */
 96int fpga_region_program_fpga(struct fpga_region *region)
 97{
 98	struct device *dev = &region->dev;
 99	struct fpga_image_info *info = region->info;
100	int ret;
101
102	region = fpga_region_get(region);
103	if (IS_ERR(region)) {
104		dev_err(dev, "failed to get FPGA region\n");
105		return PTR_ERR(region);
106	}
107
108	ret = fpga_mgr_lock(region->mgr);
109	if (ret) {
110		dev_err(dev, "FPGA manager is busy\n");
111		goto err_put_region;
112	}
113
114	/*
115	 * In some cases, we already have a list of bridges in the
116	 * fpga region struct.  Or we don't have any bridges.
117	 */
118	if (region->get_bridges) {
119		ret = region->get_bridges(region);
120		if (ret) {
121			dev_err(dev, "failed to get fpga region bridges\n");
122			goto err_unlock_mgr;
123		}
124	}
125
126	ret = fpga_bridges_disable(&region->bridge_list);
127	if (ret) {
128		dev_err(dev, "failed to disable bridges\n");
129		goto err_put_br;
130	}
131
132	ret = fpga_mgr_load(region->mgr, info);
133	if (ret) {
134		dev_err(dev, "failed to load FPGA image\n");
135		goto err_put_br;
136	}
137
138	ret = fpga_bridges_enable(&region->bridge_list);
139	if (ret) {
140		dev_err(dev, "failed to enable region bridges\n");
141		goto err_put_br;
142	}
143
144	fpga_mgr_unlock(region->mgr);
145	fpga_region_put(region);
146
147	return 0;
148
149err_put_br:
150	if (region->get_bridges)
151		fpga_bridges_put(&region->bridge_list);
152err_unlock_mgr:
153	fpga_mgr_unlock(region->mgr);
154err_put_region:
155	fpga_region_put(region);
156
157	return ret;
158}
159EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
160
161static ssize_t compat_id_show(struct device *dev,
162			      struct device_attribute *attr, char *buf)
163{
164	struct fpga_region *region = to_fpga_region(dev);
165
166	if (!region->compat_id)
167		return -ENOENT;
168
169	return sprintf(buf, "%016llx%016llx\n",
170		       (unsigned long long)region->compat_id->id_h,
171		       (unsigned long long)region->compat_id->id_l);
172}
173
174static DEVICE_ATTR_RO(compat_id);
175
176static struct attribute *fpga_region_attrs[] = {
177	&dev_attr_compat_id.attr,
178	NULL,
179};
180ATTRIBUTE_GROUPS(fpga_region);
181
182/**
183 * fpga_region_register_full - create and register an FPGA Region device
184 * @parent: device parent
185 * @info: parameters for FPGA Region
186 *
187 * Return: struct fpga_region or ERR_PTR()
188 */
189struct fpga_region *
190fpga_region_register_full(struct device *parent, const struct fpga_region_info *info)
191{
192	struct fpga_region *region;
193	int id, ret = 0;
194
195	if (!info) {
196		dev_err(parent,
197			"Attempt to register without required info structure\n");
198		return ERR_PTR(-EINVAL);
199	}
200
201	region = kzalloc(sizeof(*region), GFP_KERNEL);
202	if (!region)
203		return ERR_PTR(-ENOMEM);
204
205	id = ida_alloc(&fpga_region_ida, GFP_KERNEL);
206	if (id < 0) {
207		ret = id;
208		goto err_free;
209	}
210
211	region->mgr = info->mgr;
212	region->compat_id = info->compat_id;
213	region->priv = info->priv;
214	region->get_bridges = info->get_bridges;
215
216	mutex_init(&region->mutex);
217	INIT_LIST_HEAD(&region->bridge_list);
218
219	region->dev.class = fpga_region_class;
220	region->dev.parent = parent;
221	region->dev.of_node = parent->of_node;
222	region->dev.id = id;
223
224	ret = dev_set_name(&region->dev, "region%d", id);
225	if (ret)
226		goto err_remove;
227
228	ret = device_register(&region->dev);
229	if (ret) {
230		put_device(&region->dev);
231		return ERR_PTR(ret);
232	}
233
234	return region;
235
236err_remove:
237	ida_free(&fpga_region_ida, id);
238err_free:
239	kfree(region);
240
241	return ERR_PTR(ret);
242}
243EXPORT_SYMBOL_GPL(fpga_region_register_full);
244
245/**
246 * fpga_region_register - create and register an FPGA Region device
247 * @parent: device parent
248 * @mgr: manager that programs this region
249 * @get_bridges: optional function to get bridges to a list
250 *
251 * This simple version of the register function should be sufficient for most users.
252 * The fpga_region_register_full() function is available for users that need to
253 * pass additional, optional parameters.
254 *
255 * Return: struct fpga_region or ERR_PTR()
256 */
257struct fpga_region *
258fpga_region_register(struct device *parent, struct fpga_manager *mgr,
259		     int (*get_bridges)(struct fpga_region *))
260{
261	struct fpga_region_info info = { 0 };
262
263	info.mgr = mgr;
264	info.get_bridges = get_bridges;
265
266	return fpga_region_register_full(parent, &info);
267}
268EXPORT_SYMBOL_GPL(fpga_region_register);
269
270/**
271 * fpga_region_unregister - unregister an FPGA region
272 * @region: FPGA region
273 *
274 * This function is intended for use in an FPGA region driver's remove function.
275 */
276void fpga_region_unregister(struct fpga_region *region)
277{
278	device_unregister(&region->dev);
279}
280EXPORT_SYMBOL_GPL(fpga_region_unregister);
281
282static void fpga_region_dev_release(struct device *dev)
283{
284	struct fpga_region *region = to_fpga_region(dev);
285
286	ida_free(&fpga_region_ida, region->dev.id);
287	kfree(region);
288}
289
290/**
291 * fpga_region_init - init function for fpga_region class
292 * Creates the fpga_region class and registers a reconfig notifier.
293 */
294static int __init fpga_region_init(void)
295{
296	fpga_region_class = class_create(THIS_MODULE, "fpga_region");
297	if (IS_ERR(fpga_region_class))
298		return PTR_ERR(fpga_region_class);
299
300	fpga_region_class->dev_groups = fpga_region_groups;
301	fpga_region_class->dev_release = fpga_region_dev_release;
302
303	return 0;
304}
305
306static void __exit fpga_region_exit(void)
307{
308	class_destroy(fpga_region_class);
309	ida_destroy(&fpga_region_ida);
310}
311
312subsys_initcall(fpga_region_init);
313module_exit(fpga_region_exit);
314
315MODULE_DESCRIPTION("FPGA Region");
316MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
317MODULE_LICENSE("GPL v2");