xref: /openbmc/linux/drivers/fpga/fpga-region.c (revision a325f174) 
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 
18 static DEFINE_IDA(fpga_region_ida);
19 static const struct class fpga_region_class;
20 
21 struct fpga_region *
22 fpga_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 }
33 EXPORT_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  */
46 static 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  */
72 static 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  */
97 int 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 
150 err_put_br:
151 	if (region->get_bridges)
152 		fpga_bridges_put(&region->bridge_list);
153 err_unlock_mgr:
154 	fpga_mgr_unlock(region->mgr);
155 err_put_region:
156 	fpga_region_put(region);
157 
158 	return ret;
159 }
160 EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
161 
162 static 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 
175 static DEVICE_ATTR_RO(compat_id);
176 
177 static struct attribute *fpga_region_attrs[] = {
178 	&dev_attr_compat_id.attr,
179 	NULL,
180 };
181 ATTRIBUTE_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  */
190 struct fpga_region *
191 fpga_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 
237 err_remove:
238 	ida_free(&fpga_region_ida, id);
239 err_free:
240 	kfree(region);
241 
242 	return ERR_PTR(ret);
243 }
244 EXPORT_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  */
258 struct fpga_region *
259 fpga_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 }
269 EXPORT_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  */
277 void fpga_region_unregister(struct fpga_region *region)
278 {
279 	device_unregister(&region->dev);
280 }
281 EXPORT_SYMBOL_GPL(fpga_region_unregister);
282 
283 static 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 
291 static 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  */
302 static int __init fpga_region_init(void)
303 {
304 	return class_register(&fpga_region_class);
305 }
306 
307 static void __exit fpga_region_exit(void)
308 {
309 	class_unregister(&fpga_region_class);
310 	ida_destroy(&fpga_region_ida);
311 }
312 
313 subsys_initcall(fpga_region_init);
314 module_exit(fpga_region_exit);
315 
316 MODULE_DESCRIPTION("FPGA Region");
317 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
318 MODULE_LICENSE("GPL v2");
319