drivers/fpga/fpga-region.c

   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
  30 static DEFINE_IDA(fpga_region_ida);
  31 static struct class *fpga_region_class;
  32
  33 struct 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 }
  45 EXPORT_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  */
  57 static 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  */
  83 static 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  */
 100 int 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
 153 err_put_br:
 154         if (region->get_bridges)
 155                 fpga_bridges_put(&region->bridge_list);
 156 err_unlock_mgr:
 157         fpga_mgr_unlock(region->mgr);
 158 err_put_region:
 159         fpga_region_put(region);
 160
 161         return ret;
 162 }
 163 EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
 164
 165 int 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
 193 err_remove:
 194         ida_simple_remove(&fpga_region_ida, id);
 195         return ret;
 196 }
 197 EXPORT_SYMBOL_GPL(fpga_region_register);
 198
 199 int fpga_region_unregister(struct fpga_region *region)
 200 {
 201         device_unregister(&region->dev);
 202
 203         return 0;
 204 }
 205 EXPORT_SYMBOL_GPL(fpga_region_unregister);
 206
 207 static 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  */
 218 static 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
 229 static void __exit fpga_region_exit(void)
 230 {
 231         class_destroy(fpga_region_class);
 232         ida_destroy(&fpga_region_ida);
 233 }
 234
 235 subsys_initcall(fpga_region_init);
 236 module_exit(fpga_region_exit);
 237
 238 MODULE_DESCRIPTION("FPGA Region");
 239 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
 240 MODULE_LICENSE("GPL v2");