1// SPDX-License-Identifier: GPL-2.0
2/*
3 * FPGA Region - Device Tree 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 *fpga_region_class_find(
22 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 a 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 a 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_create - alloc and init a struct fpga_region
184 * @dev: device parent
185 * @mgr: manager that programs this region
186 * @get_bridges: optional function to get bridges to a list
187 *
188 * The caller of this function is responsible for freeing the resulting region
189 * struct with fpga_region_free(). Using devm_fpga_region_create() instead is
190 * recommended.
191 *
192 * Return: struct fpga_region or NULL
193 */
194struct fpga_region
195*fpga_region_create(struct device *dev,
196 struct fpga_manager *mgr,
197 int (*get_bridges)(struct fpga_region *))
198{
199 struct fpga_region *region;
200 int id, ret = 0;
201
202 region = kzalloc(sizeof(*region), GFP_KERNEL);
203 if (!region)
204 return NULL;
205
206 id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
207 if (id < 0)
208 goto err_free;
209
210 region->mgr = mgr;
211 region->get_bridges = get_bridges;
212 mutex_init(&region->mutex);
213 INIT_LIST_HEAD(&region->bridge_list);
214
215 device_initialize(&region->dev);
216 region->dev.class = fpga_region_class;
217 region->dev.parent = dev;
218 region->dev.of_node = dev->of_node;
219 region->dev.id = id;
220
221 ret = dev_set_name(&region->dev, "region%d", id);
222 if (ret)
223 goto err_remove;
224
225 return region;
226
227err_remove:
228 ida_simple_remove(&fpga_region_ida, id);
229err_free:
230 kfree(region);
231
232 return NULL;
233}
234EXPORT_SYMBOL_GPL(fpga_region_create);
235
236/**
237 * fpga_region_free - free a FPGA region created by fpga_region_create()
238 * @region: FPGA region
239 */
240void fpga_region_free(struct fpga_region *region)
241{
242 ida_simple_remove(&fpga_region_ida, region->dev.id);
243 kfree(region);
244}
245EXPORT_SYMBOL_GPL(fpga_region_free);
246
247static void devm_fpga_region_release(struct device *dev, void *res)
248{
249 struct fpga_region *region = *(struct fpga_region **)res;
250
251 fpga_region_free(region);
252}
253
254/**
255 * devm_fpga_region_create - create and initialize a managed FPGA region struct
256 * @dev: device parent
257 * @mgr: manager that programs this region
258 * @get_bridges: optional function to get bridges to a list
259 *
260 * This function is intended for use in a FPGA region driver's probe function.
261 * After the region driver creates the region struct with
262 * devm_fpga_region_create(), it should register it with fpga_region_register().
263 * The region driver's remove function should call fpga_region_unregister().
264 * The region struct allocated with this function will be freed automatically on
265 * driver detach. This includes the case of a probe function returning error
266 * before calling fpga_region_register(), the struct will still get cleaned up.
267 *
268 * Return: struct fpga_region or NULL
269 */
270struct fpga_region
271*devm_fpga_region_create(struct device *dev,
272 struct fpga_manager *mgr,
273 int (*get_bridges)(struct fpga_region *))
274{
275 struct fpga_region **ptr, *region;
276
277 ptr = devres_alloc(devm_fpga_region_release, sizeof(*ptr), GFP_KERNEL);
278 if (!ptr)
279 return NULL;
280
281 region = fpga_region_create(dev, mgr, get_bridges);
282 if (!region) {
283 devres_free(ptr);
284 } else {
285 *ptr = region;
286 devres_add(dev, ptr);
287 }
288
289 return region;
290}
291EXPORT_SYMBOL_GPL(devm_fpga_region_create);
292
293/**
294 * fpga_region_register - register a FPGA region
295 * @region: FPGA region
296 *
297 * Return: 0 or -errno
298 */
299int fpga_region_register(struct fpga_region *region)
300{
301 return device_add(&region->dev);
302}
303EXPORT_SYMBOL_GPL(fpga_region_register);
304
305/**
306 * fpga_region_unregister - unregister a FPGA region
307 * @region: FPGA region
308 *
309 * This function is intended for use in a FPGA region driver's remove function.
310 */
311void fpga_region_unregister(struct fpga_region *region)
312{
313 device_unregister(&region->dev);
314}
315EXPORT_SYMBOL_GPL(fpga_region_unregister);
316
317static void fpga_region_dev_release(struct device *dev)
318{
319}
320
321/**
322 * fpga_region_init - init function for fpga_region class
323 * Creates the fpga_region class and registers a reconfig notifier.
324 */
325static int __init fpga_region_init(void)
326{
327 fpga_region_class = class_create(THIS_MODULE, "fpga_region");
328 if (IS_ERR(fpga_region_class))
329 return PTR_ERR(fpga_region_class);
330
331 fpga_region_class->dev_groups = fpga_region_groups;
332 fpga_region_class->dev_release = fpga_region_dev_release;
333
334 return 0;
335}
336
337static void __exit fpga_region_exit(void)
338{
339 class_destroy(fpga_region_class);
340 ida_destroy(&fpga_region_ida);
341}
342
343subsys_initcall(fpga_region_init);
344module_exit(fpga_region_exit);
345
346MODULE_DESCRIPTION("FPGA Region");
347MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
348MODULE_LICENSE("GPL v2");
349