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/of_platform.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18 
19 static const struct of_device_id fpga_region_of_match[] = {
20 	{ .compatible = "fpga-region", },
21 	{},
22 };
23 MODULE_DEVICE_TABLE(of, fpga_region_of_match);
24 
25 /**
26  * of_fpga_region_find - find FPGA region
27  * @np: device node of FPGA Region
28  *
29  * Caller will need to put_device(&region->dev) when done.
30  *
31  * Return: FPGA Region struct or NULL
32  */
of_fpga_region_find(struct device_node * np)33 static struct fpga_region *of_fpga_region_find(struct device_node *np)
34 {
35 	return fpga_region_class_find(NULL, np, device_match_of_node);
36 }
37 
38 /**
39  * of_fpga_region_get_mgr - get reference for FPGA manager
40  * @np: device node of FPGA region
41  *
42  * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
43  *
44  * Caller should call fpga_mgr_put() when done with manager.
45  *
46  * Return: fpga manager struct or IS_ERR() condition containing error code.
47  */
of_fpga_region_get_mgr(struct device_node * np)48 static struct fpga_manager *of_fpga_region_get_mgr(struct device_node *np)
49 {
50 	struct device_node  *mgr_node;
51 	struct fpga_manager *mgr;
52 
53 	of_node_get(np);
54 	while (np) {
55 		if (of_device_is_compatible(np, "fpga-region")) {
56 			mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
57 			if (mgr_node) {
58 				mgr = of_fpga_mgr_get(mgr_node);
59 				of_node_put(mgr_node);
60 				of_node_put(np);
61 				return mgr;
62 			}
63 		}
64 		np = of_get_next_parent(np);
65 	}
66 	of_node_put(np);
67 
68 	return ERR_PTR(-EINVAL);
69 }
70 
71 /**
72  * of_fpga_region_get_bridges - create a list of bridges
73  * @region: FPGA region
74  *
75  * Create a list of bridges including the parent bridge and the bridges
76  * specified by "fpga-bridges" property.  Note that the
77  * fpga_bridges_enable/disable/put functions are all fine with an empty list
78  * if that happens.
79  *
80  * Caller should call fpga_bridges_put(&region->bridge_list) when
81  * done with the bridges.
82  *
83  * Return: 0 for success (even if there are no bridges specified)
84  * or -EBUSY if any of the bridges are in use.
85  */
of_fpga_region_get_bridges(struct fpga_region * region)86 static int of_fpga_region_get_bridges(struct fpga_region *region)
87 {
88 	struct device *dev = &region->dev;
89 	struct device_node *region_np = dev->of_node;
90 	struct fpga_image_info *info = region->info;
91 	struct device_node *br, *np, *parent_br = NULL;
92 	int i, ret;
93 
94 	/* If parent is a bridge, add to list */
95 	ret = of_fpga_bridge_get_to_list(region_np->parent, info,
96 					 &region->bridge_list);
97 
98 	/* -EBUSY means parent is a bridge that is under use. Give up. */
99 	if (ret == -EBUSY)
100 		return ret;
101 
102 	/* Zero return code means parent was a bridge and was added to list. */
103 	if (!ret)
104 		parent_br = region_np->parent;
105 
106 	/* If overlay has a list of bridges, use it. */
107 	br = of_parse_phandle(info->overlay, "fpga-bridges", 0);
108 	if (br) {
109 		of_node_put(br);
110 		np = info->overlay;
111 	} else {
112 		np = region_np;
113 	}
114 
115 	for (i = 0; ; i++) {
116 		br = of_parse_phandle(np, "fpga-bridges", i);
117 		if (!br)
118 			break;
119 
120 		/* If parent bridge is in list, skip it. */
121 		if (br == parent_br) {
122 			of_node_put(br);
123 			continue;
124 		}
125 
126 		/* If node is a bridge, get it and add to list */
127 		ret = of_fpga_bridge_get_to_list(br, info,
128 						 &region->bridge_list);
129 		of_node_put(br);
130 
131 		/* If any of the bridges are in use, give up */
132 		if (ret == -EBUSY) {
133 			fpga_bridges_put(&region->bridge_list);
134 			return -EBUSY;
135 		}
136 	}
137 
138 	return 0;
139 }
140 
141 /**
142  * child_regions_with_firmware - Used to check the child region info.
143  * @overlay: device node of the overlay
144  *
145  * If the overlay adds child FPGA regions, they are not allowed to have
146  * firmware-name property.
147  *
148  * Return: 0 for OK or -EINVAL if child FPGA region adds firmware-name.
149  */
child_regions_with_firmware(struct device_node * overlay)150 static int child_regions_with_firmware(struct device_node *overlay)
151 {
152 	struct device_node *child_region;
153 	const char *child_firmware_name;
154 	int ret = 0;
155 
156 	of_node_get(overlay);
157 
158 	child_region = of_find_matching_node(overlay, fpga_region_of_match);
159 	while (child_region) {
160 		if (!of_property_read_string(child_region, "firmware-name",
161 					     &child_firmware_name)) {
162 			ret = -EINVAL;
163 			break;
164 		}
165 		child_region = of_find_matching_node(child_region,
166 						     fpga_region_of_match);
167 	}
168 
169 	of_node_put(child_region);
170 
171 	if (ret)
172 		pr_err("firmware-name not allowed in child FPGA region: %pOF",
173 		       child_region);
174 
175 	return ret;
176 }
177 
178 /**
179  * of_fpga_region_parse_ov - parse and check overlay applied to region
180  *
181  * @region: FPGA region
182  * @overlay: overlay applied to the FPGA region
183  *
184  * Given an overlay applied to an FPGA region, parse the FPGA image specific
185  * info in the overlay and do some checking.
186  *
187  * Return:
188  *   NULL if overlay doesn't direct us to program the FPGA.
189  *   fpga_image_info struct if there is an image to program.
190  *   error code for invalid overlay.
191  */
192 static struct fpga_image_info *
of_fpga_region_parse_ov(struct fpga_region * region,struct device_node * overlay)193 of_fpga_region_parse_ov(struct fpga_region *region,
194 			struct device_node *overlay)
195 {
196 	struct device *dev = &region->dev;
197 	struct fpga_image_info *info;
198 	const char *firmware_name;
199 	int ret;
200 
201 	if (region->info) {
202 		dev_err(dev, "Region already has overlay applied.\n");
203 		return ERR_PTR(-EINVAL);
204 	}
205 
206 	/*
207 	 * Reject overlay if child FPGA Regions added in the overlay have
208 	 * firmware-name property (would mean that an FPGA region that has
209 	 * not been added to the live tree yet is doing FPGA programming).
210 	 */
211 	ret = child_regions_with_firmware(overlay);
212 	if (ret)
213 		return ERR_PTR(ret);
214 
215 	info = fpga_image_info_alloc(dev);
216 	if (!info)
217 		return ERR_PTR(-ENOMEM);
218 
219 	info->overlay = overlay;
220 
221 	/* Read FPGA region properties from the overlay */
222 	if (of_property_read_bool(overlay, "partial-fpga-config"))
223 		info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
224 
225 	if (of_property_read_bool(overlay, "external-fpga-config"))
226 		info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
227 
228 	if (of_property_read_bool(overlay, "encrypted-fpga-config"))
229 		info->flags |= FPGA_MGR_ENCRYPTED_BITSTREAM;
230 
231 	if (!of_property_read_string(overlay, "firmware-name",
232 				     &firmware_name)) {
233 		info->firmware_name = devm_kstrdup(dev, firmware_name,
234 						   GFP_KERNEL);
235 		if (!info->firmware_name)
236 			return ERR_PTR(-ENOMEM);
237 	}
238 
239 	of_property_read_u32(overlay, "region-unfreeze-timeout-us",
240 			     &info->enable_timeout_us);
241 
242 	of_property_read_u32(overlay, "region-freeze-timeout-us",
243 			     &info->disable_timeout_us);
244 
245 	of_property_read_u32(overlay, "config-complete-timeout-us",
246 			     &info->config_complete_timeout_us);
247 
248 	/* If overlay is not programming the FPGA, don't need FPGA image info */
249 	if (!info->firmware_name) {
250 		ret = 0;
251 		goto ret_no_info;
252 	}
253 
254 	/*
255 	 * If overlay informs us FPGA was externally programmed, specifying
256 	 * firmware here would be ambiguous.
257 	 */
258 	if (info->flags & FPGA_MGR_EXTERNAL_CONFIG) {
259 		dev_err(dev, "error: specified firmware and external-fpga-config");
260 		ret = -EINVAL;
261 		goto ret_no_info;
262 	}
263 
264 	return info;
265 ret_no_info:
266 	fpga_image_info_free(info);
267 	return ERR_PTR(ret);
268 }
269 
270 /**
271  * of_fpga_region_notify_pre_apply - pre-apply overlay notification
272  *
273  * @region: FPGA region that the overlay was applied to
274  * @nd: overlay notification data
275  *
276  * Called when an overlay targeted to an FPGA Region is about to be applied.
277  * Parses the overlay for properties that influence how the FPGA will be
278  * programmed and does some checking. If the checks pass, programs the FPGA.
279  * If the checks fail, overlay is rejected and does not get added to the
280  * live tree.
281  *
282  * Return: 0 for success or negative error code for failure.
283  */
of_fpga_region_notify_pre_apply(struct fpga_region * region,struct of_overlay_notify_data * nd)284 static int of_fpga_region_notify_pre_apply(struct fpga_region *region,
285 					   struct of_overlay_notify_data *nd)
286 {
287 	struct device *dev = &region->dev;
288 	struct fpga_image_info *info;
289 	int ret;
290 
291 	info = of_fpga_region_parse_ov(region, nd->overlay);
292 	if (IS_ERR(info))
293 		return PTR_ERR(info);
294 
295 	/* If overlay doesn't program the FPGA, accept it anyway. */
296 	if (!info)
297 		return 0;
298 
299 	if (region->info) {
300 		dev_err(dev, "Region already has overlay applied.\n");
301 		return -EINVAL;
302 	}
303 
304 	region->info = info;
305 	ret = fpga_region_program_fpga(region);
306 	if (ret) {
307 		/* error; reject overlay */
308 		fpga_image_info_free(info);
309 		region->info = NULL;
310 	}
311 
312 	return ret;
313 }
314 
315 /**
316  * of_fpga_region_notify_post_remove - post-remove overlay notification
317  *
318  * @region: FPGA region that was targeted by the overlay that was removed
319  * @nd: overlay notification data
320  *
321  * Called after an overlay has been removed if the overlay's target was a
322  * FPGA region.
323  */
of_fpga_region_notify_post_remove(struct fpga_region * region,struct of_overlay_notify_data * nd)324 static void of_fpga_region_notify_post_remove(struct fpga_region *region,
325 					      struct of_overlay_notify_data *nd)
326 {
327 	fpga_bridges_disable(&region->bridge_list);
328 	fpga_bridges_put(&region->bridge_list);
329 	fpga_image_info_free(region->info);
330 	region->info = NULL;
331 }
332 
333 /**
334  * of_fpga_region_notify - reconfig notifier for dynamic DT changes
335  * @nb:		notifier block
336  * @action:	notifier action
337  * @arg:	reconfig data
338  *
339  * This notifier handles programming an FPGA when a "firmware-name" property is
340  * added to an fpga-region.
341  *
342  * Return: NOTIFY_OK or error if FPGA programming fails.
343  */
of_fpga_region_notify(struct notifier_block * nb,unsigned long action,void * arg)344 static int of_fpga_region_notify(struct notifier_block *nb,
345 				 unsigned long action, void *arg)
346 {
347 	struct of_overlay_notify_data *nd = arg;
348 	struct fpga_region *region;
349 	int ret;
350 
351 	switch (action) {
352 	case OF_OVERLAY_PRE_APPLY:
353 		pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
354 		break;
355 	case OF_OVERLAY_POST_APPLY:
356 		pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
357 		return NOTIFY_OK;       /* not for us */
358 	case OF_OVERLAY_PRE_REMOVE:
359 		pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
360 		return NOTIFY_OK;       /* not for us */
361 	case OF_OVERLAY_POST_REMOVE:
362 		pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
363 		break;
364 	default:			/* should not happen */
365 		return NOTIFY_OK;
366 	}
367 
368 	region = of_fpga_region_find(nd->target);
369 	if (!region)
370 		return NOTIFY_OK;
371 
372 	ret = 0;
373 	switch (action) {
374 	case OF_OVERLAY_PRE_APPLY:
375 		ret = of_fpga_region_notify_pre_apply(region, nd);
376 		break;
377 
378 	case OF_OVERLAY_POST_REMOVE:
379 		of_fpga_region_notify_post_remove(region, nd);
380 		break;
381 	}
382 
383 	put_device(&region->dev);
384 
385 	if (ret)
386 		return notifier_from_errno(ret);
387 
388 	return NOTIFY_OK;
389 }
390 
391 static struct notifier_block fpga_region_of_nb = {
392 	.notifier_call = of_fpga_region_notify,
393 };
394 
of_fpga_region_probe(struct platform_device * pdev)395 static int of_fpga_region_probe(struct platform_device *pdev)
396 {
397 	struct device *dev = &pdev->dev;
398 	struct device_node *np = dev->of_node;
399 	struct fpga_region *region;
400 	struct fpga_manager *mgr;
401 	int ret;
402 
403 	/* Find the FPGA mgr specified by region or parent region. */
404 	mgr = of_fpga_region_get_mgr(np);
405 	if (IS_ERR(mgr))
406 		return -EPROBE_DEFER;
407 
408 	region = fpga_region_register(dev, mgr, of_fpga_region_get_bridges);
409 	if (IS_ERR(region)) {
410 		ret = PTR_ERR(region);
411 		goto eprobe_mgr_put;
412 	}
413 
414 	of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
415 	platform_set_drvdata(pdev, region);
416 
417 	dev_info(dev, "FPGA Region probed\n");
418 
419 	return 0;
420 
421 eprobe_mgr_put:
422 	fpga_mgr_put(mgr);
423 	return ret;
424 }
425 
of_fpga_region_remove(struct platform_device * pdev)426 static int of_fpga_region_remove(struct platform_device *pdev)
427 {
428 	struct fpga_region *region = platform_get_drvdata(pdev);
429 	struct fpga_manager *mgr = region->mgr;
430 
431 	fpga_region_unregister(region);
432 	fpga_mgr_put(mgr);
433 
434 	return 0;
435 }
436 
437 static struct platform_driver of_fpga_region_driver = {
438 	.probe = of_fpga_region_probe,
439 	.remove = of_fpga_region_remove,
440 	.driver = {
441 		.name	= "of-fpga-region",
442 		.of_match_table = of_match_ptr(fpga_region_of_match),
443 	},
444 };
445 
446 /**
447  * of_fpga_region_init - init function for fpga_region class
448  * Creates the fpga_region class and registers a reconfig notifier.
449  *
450  * Return: 0 on success, negative error code otherwise.
451  */
of_fpga_region_init(void)452 static int __init of_fpga_region_init(void)
453 {
454 	int ret;
455 
456 	ret = of_overlay_notifier_register(&fpga_region_of_nb);
457 	if (ret)
458 		return ret;
459 
460 	ret = platform_driver_register(&of_fpga_region_driver);
461 	if (ret)
462 		goto err_plat;
463 
464 	return 0;
465 
466 err_plat:
467 	of_overlay_notifier_unregister(&fpga_region_of_nb);
468 	return ret;
469 }
470 
of_fpga_region_exit(void)471 static void __exit of_fpga_region_exit(void)
472 {
473 	platform_driver_unregister(&of_fpga_region_driver);
474 	of_overlay_notifier_unregister(&fpga_region_of_nb);
475 }
476 
477 subsys_initcall(of_fpga_region_init);
478 module_exit(of_fpga_region_exit);
479 
480 MODULE_DESCRIPTION("FPGA Region");
481 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
482 MODULE_LICENSE("GPL v2");
483