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 const 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:
42 * * fpga_region struct if successful.
43 * * -EBUSY if someone already has a reference to the region.
44 * * -ENODEV if can't take parent driver module refcount.
45 */
46static struct fpga_region *fpga_region_get(struct fpga_region *region)
47{
48	struct device *dev = &region->dev;
49
50	if (!mutex_trylock(&region->mutex)) {
51		dev_dbg(dev, "%s: FPGA Region already in use\n", __func__);
52		return ERR_PTR(-EBUSY);
53	}
54
55	get_device(dev);
56	if (!try_module_get(dev->parent->driver->owner)) {
57		put_device(dev);
58		mutex_unlock(&region->mutex);
59		return ERR_PTR(-ENODEV);
60	}
61
62	dev_dbg(dev, "get\n");
63
64	return region;
65}
66
67/**
68 * fpga_region_put - release a reference to a region
69 *
70 * @region: FPGA region
71 */
72static void fpga_region_put(struct fpga_region *region)
73{
74	struct device *dev = &region->dev;
75
76	dev_dbg(dev, "put\n");
77
78	module_put(dev->parent->driver->owner);
79	put_device(dev);
80	mutex_unlock(&region->mutex);
81}
82
83/**
84 * fpga_region_program_fpga - program FPGA
85 *
86 * @region: FPGA region
87 *
88 * Program an FPGA using fpga image info (region->info).
89 * If the region has a get_bridges function, the exclusive reference for the
90 * bridges will be held if programming succeeds.  This is intended to prevent
91 * reprogramming the region until the caller considers it safe to do so.
92 * The caller will need to call fpga_bridges_put() before attempting to
93 * reprogram the region.
94 *
95 * Return: 0 for success or negative error code.
96 */
97int fpga_region_program_fpga(struct fpga_region *region)
98{
99	struct device *dev = &region->dev;
100	struct fpga_image_info *info = region->info;
101	int ret;
102
103	region = fpga_region_get(region);
104	if (IS_ERR(region)) {
105		dev_err(dev, "failed to get FPGA region\n");
106		return PTR_ERR(region);
107	}
108
109	ret = fpga_mgr_lock(region->mgr);
110	if (ret) {
111		dev_err(dev, "FPGA manager is busy\n");
112		goto err_put_region;
113	}
114
115	/*
116	 * In some cases, we already have a list of bridges in the
117	 * fpga region struct.  Or we don't have any bridges.
118	 */
119	if (region->get_bridges) {
120		ret = region->get_bridges(region);
121		if (ret) {
122			dev_err(dev, "failed to get fpga region bridges\n");
123			goto err_unlock_mgr;
124		}
125	}
126
127	ret = fpga_bridges_disable(&region->bridge_list);
128	if (ret) {
129		dev_err(dev, "failed to disable bridges\n");
130		goto err_put_br;
131	}
132
133	ret = fpga_mgr_load(region->mgr, info);
134	if (ret) {
135		dev_err(dev, "failed to load FPGA image\n");
136		goto err_put_br;
137	}
138
139	ret = fpga_bridges_enable(&region->bridge_list);
140	if (ret) {
141		dev_err(dev, "failed to enable region bridges\n");
142		goto err_put_br;
143	}
144
145	fpga_mgr_unlock(region->mgr);
146	fpga_region_put(region);
147
148	return 0;
149
150err_put_br:
151	if (region->get_bridges)
152		fpga_bridges_put(&region->bridge_list);
153err_unlock_mgr:
154	fpga_mgr_unlock(region->mgr);
155err_put_region:
156	fpga_region_put(region);
157
158	return ret;
159}
160EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
161
162static ssize_t compat_id_show(struct device *dev,
163			      struct device_attribute *attr, char *buf)
164{
165	struct fpga_region *region = to_fpga_region(dev);
166
167	if (!region->compat_id)
168		return -ENOENT;
169
170	return sprintf(buf, "%016llx%016llx\n",
171		       (unsigned long long)region->compat_id->id_h,
172		       (unsigned long long)region->compat_id->id_l);
173}
174
175static DEVICE_ATTR_RO(compat_id);
176
177static struct attribute *fpga_region_attrs[] = {
178	&dev_attr_compat_id.attr,
179	NULL,
180};
181ATTRIBUTE_GROUPS(fpga_region);
182
183/**
184 * fpga_region_register_full - create and register an FPGA Region device
185 * @parent: device parent
186 * @info: parameters for FPGA Region
187 *
188 * Return: struct fpga_region or ERR_PTR()
189 */
190struct fpga_region *
191fpga_region_register_full(struct device *parent, const struct fpga_region_info *info)
192{
193	struct fpga_region *region;
194	int id, ret = 0;
195
196	if (!info) {
197		dev_err(parent,
198			"Attempt to register without required info structure\n");
199		return ERR_PTR(-EINVAL);
200	}
201
202	region = kzalloc(sizeof(*region), GFP_KERNEL);
203	if (!region)
204		return ERR_PTR(-ENOMEM);
205
206	id = ida_alloc(&fpga_region_ida, GFP_KERNEL);
207	if (id < 0) {
208		ret = id;
209		goto err_free;
210	}
211
212	region->mgr = info->mgr;
213	region->compat_id = info->compat_id;
214	region->priv = info->priv;
215	region->get_bridges = info->get_bridges;
216
217	mutex_init(&region->mutex);
218	INIT_LIST_HEAD(&region->bridge_list);
219
220	region->dev.class = &fpga_region_class;
221	region->dev.parent = parent;
222	region->dev.of_node = parent->of_node;
223	region->dev.id = id;
224
225	ret = dev_set_name(&region->dev, "region%d", id);
226	if (ret)
227		goto err_remove;
228
229	ret = device_register(&region->dev);
230	if (ret) {
231		put_device(&region->dev);
232		return ERR_PTR(ret);
233	}
234
235	return region;
236
237err_remove:
238	ida_free(&fpga_region_ida, id);
239err_free:
240	kfree(region);
241
242	return ERR_PTR(ret);
243}
244EXPORT_SYMBOL_GPL(fpga_region_register_full);
245
246/**
247 * fpga_region_register - create and register an FPGA Region device
248 * @parent: device parent
249 * @mgr: manager that programs this region
250 * @get_bridges: optional function to get bridges to a list
251 *
252 * This simple version of the register function should be sufficient for most users.
253 * The fpga_region_register_full() function is available for users that need to
254 * pass additional, optional parameters.
255 *
256 * Return: struct fpga_region or ERR_PTR()
257 */
258struct fpga_region *
259fpga_region_register(struct device *parent, struct fpga_manager *mgr,
260		     int (*get_bridges)(struct fpga_region *))
261{
262	struct fpga_region_info info = { 0 };
263
264	info.mgr = mgr;
265	info.get_bridges = get_bridges;
266
267	return fpga_region_register_full(parent, &info);
268}
269EXPORT_SYMBOL_GPL(fpga_region_register);
270
271/**
272 * fpga_region_unregister - unregister an FPGA region
273 * @region: FPGA region
274 *
275 * This function is intended for use in an FPGA region driver's remove function.
276 */
277void fpga_region_unregister(struct fpga_region *region)
278{
279	device_unregister(&region->dev);
280}
281EXPORT_SYMBOL_GPL(fpga_region_unregister);
282
283static void fpga_region_dev_release(struct device *dev)
284{
285	struct fpga_region *region = to_fpga_region(dev);
286
287	ida_free(&fpga_region_ida, region->dev.id);
288	kfree(region);
289}
290
291static const struct class fpga_region_class = {
292	.name = "fpga_region",
293	.dev_groups = fpga_region_groups,
294	.dev_release = fpga_region_dev_release,
295};
296
297/**
298 * fpga_region_init - creates the fpga_region class.
299 *
300 * Return: 0 on success or ERR_PTR() on error.
301 */
302static int __init fpga_region_init(void)
303{
304	return class_register(&fpga_region_class);
305}
306
307static void __exit fpga_region_exit(void)
308{
309	class_unregister(&fpga_region_class);
310	ida_destroy(&fpga_region_ida);
311}
312
313subsys_initcall(fpga_region_init);
314module_exit(fpga_region_exit);
315
316MODULE_DESCRIPTION("FPGA Region");
317MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
318MODULE_LICENSE("GPL v2");
319