xref: /openbmc/linux/drivers/fpga/fpga-region.c (revision cd238eff) 
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 
18 static DEFINE_IDA(fpga_region_ida);
19 static struct class *fpga_region_class;
20 
21 struct 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 }
33 EXPORT_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  */
45 static 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  */
71 static 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  */
96 int 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 
149 err_put_br:
150 	if (region->get_bridges)
151 		fpga_bridges_put(&region->bridge_list);
152 err_unlock_mgr:
153 	fpga_mgr_unlock(region->mgr);
154 err_put_region:
155 	fpga_region_put(region);
156 
157 	return ret;
158 }
159 EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
160 
161 static 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 
174 static DEVICE_ATTR_RO(compat_id);
175 
176 static struct attribute *fpga_region_attrs[] = {
177 	&dev_attr_compat_id.attr,
178 	NULL,
179 };
180 ATTRIBUTE_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  */
194 struct 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 
227 err_remove:
228 	ida_simple_remove(&fpga_region_ida, id);
229 err_free:
230 	kfree(region);
231 
232 	return NULL;
233 }
234 EXPORT_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  */
240 void fpga_region_free(struct fpga_region *region)
241 {
242 	ida_simple_remove(&fpga_region_ida, region->dev.id);
243 	kfree(region);
244 }
245 EXPORT_SYMBOL_GPL(fpga_region_free);
246 
247 static 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  */
270 struct 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 }
291 EXPORT_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  */
299 int fpga_region_register(struct fpga_region *region)
300 {
301 	return device_add(&region->dev);
302 }
303 EXPORT_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  */
311 void fpga_region_unregister(struct fpga_region *region)
312 {
313 	device_unregister(&region->dev);
314 }
315 EXPORT_SYMBOL_GPL(fpga_region_unregister);
316 
317 static 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  */
325 static 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 
337 static void __exit fpga_region_exit(void)
338 {
339 	class_destroy(fpga_region_class);
340 	ida_destroy(&fpga_region_ida);
341 }
342 
343 subsys_initcall(fpga_region_init);
344 module_exit(fpga_region_exit);
345 
346 MODULE_DESCRIPTION("FPGA Region");
347 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
348 MODULE_LICENSE("GPL v2");
349