1/*
  2 * FPGA Region - Device Tree support for FPGA programming under Linux
  3 *
  4 *  Copyright (C) 2013-2016 Altera Corporation
  5 *  Copyright (C) 2017 Intel Corporation
  6 *
  7 * This program is free software; you can redistribute it and/or modify it
  8 * under the terms and conditions of the GNU General Public License,
  9 * version 2, as published by the Free Software Foundation.
 10 *
 11 * This program is distributed in the hope it will be useful, but WITHOUT
 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 14 * more details.
 15 *
 16 * You should have received a copy of the GNU General Public License along with
 17 * this program.  If not, see <http://www.gnu.org/licenses/>.
 18 */
 19
 20#include <linux/fpga/fpga-bridge.h>
 21#include <linux/fpga/fpga-mgr.h>
 22#include <linux/fpga/fpga-region.h>
 23#include <linux/idr.h>
 24#include <linux/kernel.h>
 25#include <linux/list.h>
 26#include <linux/module.h>
 27#include <linux/slab.h>
 28#include <linux/spinlock.h>
 29
 30static DEFINE_IDA(fpga_region_ida);
 31static struct class *fpga_region_class;
 32
 33struct fpga_region *fpga_region_class_find(
 34	struct device *start, const void *data,
 35	int (*match)(struct device *, const void *))
 36{
 37	struct device *dev;
 38
 39	dev = class_find_device(fpga_region_class, start, data, match);
 40	if (!dev)
 41		return NULL;
 42
 43	return to_fpga_region(dev);
 44}
 45EXPORT_SYMBOL_GPL(fpga_region_class_find);
 46
 47/**
 48 * fpga_region_get - get an exclusive reference to a fpga region
 49 * @region: FPGA Region struct
 50 *
 51 * Caller should call fpga_region_put() when done with region.
 52 *
 53 * Return fpga_region struct if successful.
 54 * Return -EBUSY if someone already has a reference to the region.
 55 * Return -ENODEV if @np is not a FPGA Region.
 56 */
 57static struct fpga_region *fpga_region_get(struct fpga_region *region)
 58{
 59	struct device *dev = &region->dev;
 60
 61	if (!mutex_trylock(&region->mutex)) {
 62		dev_dbg(dev, "%s: FPGA Region already in use\n", __func__);
 63		return ERR_PTR(-EBUSY);
 64	}
 65
 66	get_device(dev);
 67	if (!try_module_get(dev->parent->driver->owner)) {
 68		put_device(dev);
 69		mutex_unlock(&region->mutex);
 70		return ERR_PTR(-ENODEV);
 71	}
 72
 73	dev_dbg(dev, "get\n");
 74
 75	return region;
 76}
 77
 78/**
 79 * fpga_region_put - release a reference to a region
 80 *
 81 * @region: FPGA region
 82 */
 83static void fpga_region_put(struct fpga_region *region)
 84{
 85	struct device *dev = &region->dev;
 86
 87	dev_dbg(dev, "put\n");
 88
 89	module_put(dev->parent->driver->owner);
 90	put_device(dev);
 91	mutex_unlock(&region->mutex);
 92}
 93
 94/**
 95 * fpga_region_program_fpga - program FPGA
 96 * @region: FPGA region
 97 * Program an FPGA using fpga image info (region->info).
 98 * Return 0 for success or negative error code.
 99 */
100int fpga_region_program_fpga(struct fpga_region *region)
101{
102	struct device *dev = &region->dev;
103	struct fpga_image_info *info = region->info;
104	int ret;
105
106	region = fpga_region_get(region);
107	if (IS_ERR(region)) {
108		dev_err(dev, "failed to get FPGA region\n");
109		return PTR_ERR(region);
110	}
111
112	ret = fpga_mgr_lock(region->mgr);
113	if (ret) {
114		dev_err(dev, "FPGA manager is busy\n");
115		goto err_put_region;
116	}
117
118	/*
119	 * In some cases, we already have a list of bridges in the
120	 * fpga region struct.  Or we don't have any bridges.
121	 */
122	if (region->get_bridges) {
123		ret = region->get_bridges(region);
124		if (ret) {
125			dev_err(dev, "failed to get fpga region bridges\n");
126			goto err_unlock_mgr;
127		}
128	}
129
130	ret = fpga_bridges_disable(&region->bridge_list);
131	if (ret) {
132		dev_err(dev, "failed to disable bridges\n");
133		goto err_put_br;
134	}
135
136	ret = fpga_mgr_load(region->mgr, info);
137	if (ret) {
138		dev_err(dev, "failed to load FPGA image\n");
139		goto err_put_br;
140	}
141
142	ret = fpga_bridges_enable(&region->bridge_list);
143	if (ret) {
144		dev_err(dev, "failed to enable region bridges\n");
145		goto err_put_br;
146	}
147
148	fpga_mgr_unlock(region->mgr);
149	fpga_region_put(region);
150
151	return 0;
152
153err_put_br:
154	if (region->get_bridges)
155		fpga_bridges_put(&region->bridge_list);
156err_unlock_mgr:
157	fpga_mgr_unlock(region->mgr);
158err_put_region:
159	fpga_region_put(region);
160
161	return ret;
162}
163EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
164
165int fpga_region_register(struct device *dev, struct fpga_region *region)
166{
167	int id, ret = 0;
168
169	id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
170	if (id < 0)
171		return id;
172
173	mutex_init(&region->mutex);
174	INIT_LIST_HEAD(&region->bridge_list);
175	device_initialize(&region->dev);
176	region->dev.groups = region->groups;
177	region->dev.class = fpga_region_class;
178	region->dev.parent = dev;
179	region->dev.of_node = dev->of_node;
180	region->dev.id = id;
181	dev_set_drvdata(dev, region);
182
183	ret = dev_set_name(&region->dev, "region%d", id);
184	if (ret)
185		goto err_remove;
186
187	ret = device_add(&region->dev);
188	if (ret)
189		goto err_remove;
190
191	return 0;
192
193err_remove:
194	ida_simple_remove(&fpga_region_ida, id);
195	return ret;
196}
197EXPORT_SYMBOL_GPL(fpga_region_register);
198
199int fpga_region_unregister(struct fpga_region *region)
200{
201	device_unregister(&region->dev);
202
203	return 0;
204}
205EXPORT_SYMBOL_GPL(fpga_region_unregister);
206
207static void fpga_region_dev_release(struct device *dev)
208{
209	struct fpga_region *region = to_fpga_region(dev);
210
211	ida_simple_remove(&fpga_region_ida, region->dev.id);
212}
213
214/**
215 * fpga_region_init - init function for fpga_region class
216 * Creates the fpga_region class and registers a reconfig notifier.
217 */
218static int __init fpga_region_init(void)
219{
220	fpga_region_class = class_create(THIS_MODULE, "fpga_region");
221	if (IS_ERR(fpga_region_class))
222		return PTR_ERR(fpga_region_class);
223
224	fpga_region_class->dev_release = fpga_region_dev_release;
225
226	return 0;
227}
228
229static void __exit fpga_region_exit(void)
230{
231	class_destroy(fpga_region_class);
232	ida_destroy(&fpga_region_ida);
233}
234
235subsys_initcall(fpga_region_init);
236module_exit(fpga_region_exit);
237
238MODULE_DESCRIPTION("FPGA Region");
239MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
240MODULE_LICENSE("GPL v2");