1/*
  2 * FPGA Region - Device Tree support for FPGA programming under Linux
  3 *
  4 *  Copyright (C) 2013-2016 Altera Corporation
  5 *
  6 * This program is free software; you can redistribute it and/or modify it
  7 * under the terms and conditions of the GNU General Public License,
  8 * version 2, as published by the Free Software Foundation.
  9 *
 10 * This program is distributed in the hope it will be useful, but WITHOUT
 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 13 * more details.
 14 *
 15 * You should have received a copy of the GNU General Public License along with
 16 * this program.  If not, see <http://www.gnu.org/licenses/>.
 17 */
 18
 19#include <linux/fpga/fpga-bridge.h>
 20#include <linux/fpga/fpga-mgr.h>
 21#include <linux/idr.h>
 22#include <linux/kernel.h>
 23#include <linux/list.h>
 24#include <linux/module.h>
 25#include <linux/of_platform.h>
 26#include <linux/slab.h>
 27#include <linux/spinlock.h>
 28
 29/**
 30 * struct fpga_region - FPGA Region structure
 31 * @dev: FPGA Region device
 32 * @mutex: enforces exclusive reference to region
 33 * @bridge_list: list of FPGA bridges specified in region
 34 * @info: fpga image specific information
 35 */
 36struct fpga_region {
 37	struct device dev;
 38	struct mutex mutex; /* for exclusive reference to region */
 39	struct list_head bridge_list;
 40	struct fpga_image_info *info;
 41};
 42
 43#define to_fpga_region(d) container_of(d, struct fpga_region, dev)
 44
 45static DEFINE_IDA(fpga_region_ida);
 46static struct class *fpga_region_class;
 47
 48static const struct of_device_id fpga_region_of_match[] = {
 49	{ .compatible = "fpga-region", },
 50	{},
 51};
 52MODULE_DEVICE_TABLE(of, fpga_region_of_match);
 53
 54static int fpga_region_of_node_match(struct device *dev, const void *data)
 55{
 56	return dev->of_node == data;
 57}
 58
 59/**
 60 * fpga_region_find - find FPGA region
 61 * @np: device node of FPGA Region
 62 * Caller will need to put_device(&region->dev) when done.
 63 * Returns FPGA Region struct or NULL
 64 */
 65static struct fpga_region *fpga_region_find(struct device_node *np)
 66{
 67	struct device *dev;
 68
 69	dev = class_find_device(fpga_region_class, NULL, np,
 70				fpga_region_of_node_match);
 71	if (!dev)
 72		return NULL;
 73
 74	return to_fpga_region(dev);
 75}
 76
 77/**
 78 * fpga_region_get - get an exclusive reference to a fpga region
 79 * @region: FPGA Region struct
 80 *
 81 * Caller should call fpga_region_put() when done with region.
 82 *
 83 * Return fpga_region struct if successful.
 84 * Return -EBUSY if someone already has a reference to the region.
 85 * Return -ENODEV if @np is not a FPGA Region.
 86 */
 87static struct fpga_region *fpga_region_get(struct fpga_region *region)
 88{
 89	struct device *dev = &region->dev;
 90
 91	if (!mutex_trylock(&region->mutex)) {
 92		dev_dbg(dev, "%s: FPGA Region already in use\n", __func__);
 93		return ERR_PTR(-EBUSY);
 94	}
 95
 96	get_device(dev);
 97	of_node_get(dev->of_node);
 98	if (!try_module_get(dev->parent->driver->owner)) {
 99		of_node_put(dev->of_node);
100		put_device(dev);
101		mutex_unlock(&region->mutex);
102		return ERR_PTR(-ENODEV);
103	}
104
105	dev_dbg(&region->dev, "get\n");
106
107	return region;
108}
109
110/**
111 * fpga_region_put - release a reference to a region
112 *
113 * @region: FPGA region
114 */
115static void fpga_region_put(struct fpga_region *region)
116{
117	struct device *dev = &region->dev;
118
119	dev_dbg(&region->dev, "put\n");
120
121	module_put(dev->parent->driver->owner);
122	of_node_put(dev->of_node);
123	put_device(dev);
124	mutex_unlock(&region->mutex);
125}
126
127/**
128 * fpga_region_get_manager - get exclusive reference for FPGA manager
129 * @region: FPGA region
130 *
131 * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
132 *
133 * Caller should call fpga_mgr_put() when done with manager.
134 *
135 * Return: fpga manager struct or IS_ERR() condition containing error code.
136 */
137static struct fpga_manager *fpga_region_get_manager(struct fpga_region *region)
138{
139	struct device *dev = &region->dev;
140	struct device_node *np = dev->of_node;
141	struct device_node  *mgr_node;
142	struct fpga_manager *mgr;
143
144	of_node_get(np);
145	while (np) {
146		if (of_device_is_compatible(np, "fpga-region")) {
147			mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
148			if (mgr_node) {
149				mgr = of_fpga_mgr_get(mgr_node);
150				of_node_put(np);
151				return mgr;
152			}
153		}
154		np = of_get_next_parent(np);
155	}
156	of_node_put(np);
157
158	return ERR_PTR(-EINVAL);
159}
160
161/**
162 * fpga_region_get_bridges - create a list of bridges
163 * @region: FPGA region
164 * @overlay: device node of the overlay
165 *
166 * Create a list of bridges including the parent bridge and the bridges
167 * specified by "fpga-bridges" property.  Note that the
168 * fpga_bridges_enable/disable/put functions are all fine with an empty list
169 * if that happens.
170 *
171 * Caller should call fpga_bridges_put(&region->bridge_list) when
172 * done with the bridges.
173 *
174 * Return 0 for success (even if there are no bridges specified)
175 * or -EBUSY if any of the bridges are in use.
176 */
177static int fpga_region_get_bridges(struct fpga_region *region,
178				   struct device_node *overlay)
179{
180	struct device *dev = &region->dev;
181	struct device_node *region_np = dev->of_node;
182	struct device_node *br, *np, *parent_br = NULL;
183	int i, ret;
184
185	/* If parent is a bridge, add to list */
186	ret = fpga_bridge_get_to_list(region_np->parent, region->info,
187				      &region->bridge_list);
188	if (ret == -EBUSY)
189		return ret;
190
191	if (!ret)
192		parent_br = region_np->parent;
193
194	/* If overlay has a list of bridges, use it. */
195	if (of_parse_phandle(overlay, "fpga-bridges", 0))
196		np = overlay;
197	else
198		np = region_np;
199
200	for (i = 0; ; i++) {
201		br = of_parse_phandle(np, "fpga-bridges", i);
202		if (!br)
203			break;
204
205		/* If parent bridge is in list, skip it. */
206		if (br == parent_br)
207			continue;
208
209		/* If node is a bridge, get it and add to list */
210		ret = fpga_bridge_get_to_list(br, region->info,
211					      &region->bridge_list);
212
213		/* If any of the bridges are in use, give up */
214		if (ret == -EBUSY) {
215			fpga_bridges_put(&region->bridge_list);
216			return -EBUSY;
217		}
218	}
219
220	return 0;
221}
222
223/**
224 * fpga_region_program_fpga - program FPGA
225 * @region: FPGA region
226 * @firmware_name: name of FPGA image firmware file
227 * @overlay: device node of the overlay
228 * Program an FPGA using information in the device tree.
229 * Function assumes that there is a firmware-name property.
230 * Return 0 for success or negative error code.
231 */
232static int fpga_region_program_fpga(struct fpga_region *region,
233				    const char *firmware_name,
234				    struct device_node *overlay)
235{
236	struct fpga_manager *mgr;
237	int ret;
238
239	region = fpga_region_get(region);
240	if (IS_ERR(region)) {
241		pr_err("failed to get fpga region\n");
242		return PTR_ERR(region);
243	}
244
245	mgr = fpga_region_get_manager(region);
246	if (IS_ERR(mgr)) {
247		pr_err("failed to get fpga region manager\n");
248		return PTR_ERR(mgr);
249	}
250
251	ret = fpga_region_get_bridges(region, overlay);
252	if (ret) {
253		pr_err("failed to get fpga region bridges\n");
254		goto err_put_mgr;
255	}
256
257	ret = fpga_bridges_disable(&region->bridge_list);
258	if (ret) {
259		pr_err("failed to disable region bridges\n");
260		goto err_put_br;
261	}
262
263	ret = fpga_mgr_firmware_load(mgr, region->info, firmware_name);
264	if (ret) {
265		pr_err("failed to load fpga image\n");
266		goto err_put_br;
267	}
268
269	ret = fpga_bridges_enable(&region->bridge_list);
270	if (ret) {
271		pr_err("failed to enable region bridges\n");
272		goto err_put_br;
273	}
274
275	fpga_mgr_put(mgr);
276	fpga_region_put(region);
277
278	return 0;
279
280err_put_br:
281	fpga_bridges_put(&region->bridge_list);
282err_put_mgr:
283	fpga_mgr_put(mgr);
284	fpga_region_put(region);
285
286	return ret;
287}
288
289/**
290 * child_regions_with_firmware
291 * @overlay: device node of the overlay
292 *
293 * If the overlay adds child FPGA regions, they are not allowed to have
294 * firmware-name property.
295 *
296 * Return 0 for OK or -EINVAL if child FPGA region adds firmware-name.
297 */
298static int child_regions_with_firmware(struct device_node *overlay)
299{
300	struct device_node *child_region;
301	const char *child_firmware_name;
302	int ret = 0;
303
304	of_node_get(overlay);
305
306	child_region = of_find_matching_node(overlay, fpga_region_of_match);
307	while (child_region) {
308		if (!of_property_read_string(child_region, "firmware-name",
309					     &child_firmware_name)) {
310			ret = -EINVAL;
311			break;
312		}
313		child_region = of_find_matching_node(child_region,
314						     fpga_region_of_match);
315	}
316
317	of_node_put(child_region);
318
319	if (ret)
320		pr_err("firmware-name not allowed in child FPGA region: %s",
321		       child_region->full_name);
322
323	return ret;
324}
325
326/**
327 * fpga_region_notify_pre_apply - pre-apply overlay notification
328 *
329 * @region: FPGA region that the overlay was applied to
330 * @nd: overlay notification data
331 *
332 * Called after when an overlay targeted to a FPGA Region is about to be
333 * applied.  Function will check the properties that will be added to the FPGA
334 * region.  If the checks pass, it will program the FPGA.
335 *
336 * The checks are:
337 * The overlay must add either firmware-name or external-fpga-config property
338 * to the FPGA Region.
339 *
340 *   firmware-name        : program the FPGA
341 *   external-fpga-config : FPGA is already programmed
342 *
343 * The overlay can add other FPGA regions, but child FPGA regions cannot have a
344 * firmware-name property since those regions don't exist yet.
345 *
346 * If the overlay that breaks the rules, notifier returns an error and the
347 * overlay is rejected before it goes into the main tree.
348 *
349 * Returns 0 for success or negative error code for failure.
350 */
351static int fpga_region_notify_pre_apply(struct fpga_region *region,
352					struct of_overlay_notify_data *nd)
353{
354	const char *firmware_name = NULL;
355	struct fpga_image_info *info;
356	int ret;
357
358	info = devm_kzalloc(&region->dev, sizeof(*info), GFP_KERNEL);
359	if (!info)
360		return -ENOMEM;
361
362	region->info = info;
363
364	/* Reject overlay if child FPGA Regions have firmware-name property */
365	ret = child_regions_with_firmware(nd->overlay);
366	if (ret)
367		return ret;
368
369	/* Read FPGA region properties from the overlay */
370	if (of_property_read_bool(nd->overlay, "partial-fpga-config"))
371		info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
372
373	if (of_property_read_bool(nd->overlay, "external-fpga-config"))
374		info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
375
376	of_property_read_string(nd->overlay, "firmware-name", &firmware_name);
377
378	of_property_read_u32(nd->overlay, "region-unfreeze-timeout-us",
379			     &info->enable_timeout_us);
380
381	of_property_read_u32(nd->overlay, "region-freeze-timeout-us",
382			     &info->disable_timeout_us);
383
384	/* If FPGA was externally programmed, don't specify firmware */
385	if ((info->flags & FPGA_MGR_EXTERNAL_CONFIG) && firmware_name) {
386		pr_err("error: specified firmware and external-fpga-config");
387		return -EINVAL;
388	}
389
390	/* FPGA is already configured externally.  We're done. */
391	if (info->flags & FPGA_MGR_EXTERNAL_CONFIG)
392		return 0;
393
394	/* If we got this far, we should be programming the FPGA */
395	if (!firmware_name) {
396		pr_err("should specify firmware-name or external-fpga-config\n");
397		return -EINVAL;
398	}
399
400	return fpga_region_program_fpga(region, firmware_name, nd->overlay);
401}
402
403/**
404 * fpga_region_notify_post_remove - post-remove overlay notification
405 *
406 * @region: FPGA region that was targeted by the overlay that was removed
407 * @nd: overlay notification data
408 *
409 * Called after an overlay has been removed if the overlay's target was a
410 * FPGA region.
411 */
412static void fpga_region_notify_post_remove(struct fpga_region *region,
413					   struct of_overlay_notify_data *nd)
414{
415	fpga_bridges_disable(&region->bridge_list);
416	fpga_bridges_put(&region->bridge_list);
417	devm_kfree(&region->dev, region->info);
418	region->info = NULL;
419}
420
421/**
422 * of_fpga_region_notify - reconfig notifier for dynamic DT changes
423 * @nb:		notifier block
424 * @action:	notifier action
425 * @arg:	reconfig data
426 *
427 * This notifier handles programming a FPGA when a "firmware-name" property is
428 * added to a fpga-region.
429 *
430 * Returns NOTIFY_OK or error if FPGA programming fails.
431 */
432static int of_fpga_region_notify(struct notifier_block *nb,
433				 unsigned long action, void *arg)
434{
435	struct of_overlay_notify_data *nd = arg;
436	struct fpga_region *region;
437	int ret;
438
439	switch (action) {
440	case OF_OVERLAY_PRE_APPLY:
441		pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
442		break;
443	case OF_OVERLAY_POST_APPLY:
444		pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
445		return NOTIFY_OK;       /* not for us */
446	case OF_OVERLAY_PRE_REMOVE:
447		pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
448		return NOTIFY_OK;       /* not for us */
449	case OF_OVERLAY_POST_REMOVE:
450		pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
451		break;
452	default:			/* should not happen */
453		return NOTIFY_OK;
454	}
455
456	region = fpga_region_find(nd->target);
457	if (!region)
458		return NOTIFY_OK;
459
460	ret = 0;
461	switch (action) {
462	case OF_OVERLAY_PRE_APPLY:
463		ret = fpga_region_notify_pre_apply(region, nd);
464		break;
465
466	case OF_OVERLAY_POST_REMOVE:
467		fpga_region_notify_post_remove(region, nd);
468		break;
469	}
470
471	put_device(&region->dev);
472
473	if (ret)
474		return notifier_from_errno(ret);
475
476	return NOTIFY_OK;
477}
478
479static struct notifier_block fpga_region_of_nb = {
480	.notifier_call = of_fpga_region_notify,
481};
482
483static int fpga_region_probe(struct platform_device *pdev)
484{
485	struct device *dev = &pdev->dev;
486	struct device_node *np = dev->of_node;
487	struct fpga_region *region;
488	int id, ret = 0;
489
490	region = kzalloc(sizeof(*region), GFP_KERNEL);
491	if (!region)
492		return -ENOMEM;
493
494	id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
495	if (id < 0) {
496		ret = id;
497		goto err_kfree;
498	}
499
500	mutex_init(&region->mutex);
501	INIT_LIST_HEAD(&region->bridge_list);
502
503	device_initialize(&region->dev);
504	region->dev.class = fpga_region_class;
505	region->dev.parent = dev;
506	region->dev.of_node = np;
507	region->dev.id = id;
508	dev_set_drvdata(dev, region);
509
510	ret = dev_set_name(&region->dev, "region%d", id);
511	if (ret)
512		goto err_remove;
513
514	ret = device_add(&region->dev);
515	if (ret)
516		goto err_remove;
517
518	of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
519
520	dev_info(dev, "FPGA Region probed\n");
521
522	return 0;
523
524err_remove:
525	ida_simple_remove(&fpga_region_ida, id);
526err_kfree:
527	kfree(region);
528
529	return ret;
530}
531
532static int fpga_region_remove(struct platform_device *pdev)
533{
534	struct fpga_region *region = platform_get_drvdata(pdev);
535
536	device_unregister(&region->dev);
537
538	return 0;
539}
540
541static struct platform_driver fpga_region_driver = {
542	.probe = fpga_region_probe,
543	.remove = fpga_region_remove,
544	.driver = {
545		.name	= "fpga-region",
546		.of_match_table = of_match_ptr(fpga_region_of_match),
547	},
548};
549
550static void fpga_region_dev_release(struct device *dev)
551{
552	struct fpga_region *region = to_fpga_region(dev);
553
554	ida_simple_remove(&fpga_region_ida, region->dev.id);
555	kfree(region);
556}
557
558/**
559 * fpga_region_init - init function for fpga_region class
560 * Creates the fpga_region class and registers a reconfig notifier.
561 */
562static int __init fpga_region_init(void)
563{
564	int ret;
565
566	fpga_region_class = class_create(THIS_MODULE, "fpga_region");
567	if (IS_ERR(fpga_region_class))
568		return PTR_ERR(fpga_region_class);
569
570	fpga_region_class->dev_release = fpga_region_dev_release;
571
572	ret = of_overlay_notifier_register(&fpga_region_of_nb);
573	if (ret)
574		goto err_class;
575
576	ret = platform_driver_register(&fpga_region_driver);
577	if (ret)
578		goto err_plat;
579
580	return 0;
581
582err_plat:
583	of_overlay_notifier_unregister(&fpga_region_of_nb);
584err_class:
585	class_destroy(fpga_region_class);
586	ida_destroy(&fpga_region_ida);
587	return ret;
588}
589
590static void __exit fpga_region_exit(void)
591{
592	platform_driver_unregister(&fpga_region_driver);
593	of_overlay_notifier_unregister(&fpga_region_of_nb);
594	class_destroy(fpga_region_class);
595	ida_destroy(&fpga_region_ida);
596}
597
598subsys_initcall(fpga_region_init);
599module_exit(fpga_region_exit);
600
601MODULE_DESCRIPTION("FPGA Region");
602MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
603MODULE_LICENSE("GPL v2");