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