xref: /openbmc/linux/drivers/fpga/fpga-region.c (revision 465191d6) 
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 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 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  */
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_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  */
189 struct fpga_region *
190 fpga_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_simple_get(&fpga_region_ida, 0, 0, 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 
236 err_remove:
237 	ida_simple_remove(&fpga_region_ida, id);
238 err_free:
239 	kfree(region);
240 
241 	return ERR_PTR(ret);
242 }
243 EXPORT_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  */
257 struct fpga_region *
258 fpga_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 }
268 EXPORT_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  */
276 void fpga_region_unregister(struct fpga_region *region)
277 {
278 	device_unregister(&region->dev);
279 }
280 EXPORT_SYMBOL_GPL(fpga_region_unregister);
281 
282 static void fpga_region_dev_release(struct device *dev)
283 {
284 	struct fpga_region *region = to_fpga_region(dev);
285 
286 	ida_simple_remove(&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  */
294 static 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 
306 static void __exit fpga_region_exit(void)
307 {
308 	class_destroy(fpga_region_class);
309 	ida_destroy(&fpga_region_ida);
310 }
311 
312 subsys_initcall(fpga_region_init);
313 module_exit(fpga_region_exit);
314 
315 MODULE_DESCRIPTION("FPGA Region");
316 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
317 MODULE_LICENSE("GPL v2");
318