drivers/fpga/fpga-region.c

   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/slab.h>
  16 #include <linux/spinlock.h>
  17
  18 static DEFINE_IDA(fpga_region_ida);
  19 static struct class *fpga_region_class;
  20
  21 struct fpga_region *fpga_region_class_find(
  22         struct device *start, const void *data,
  23         int (*match)(struct device *, const void *))
  24 {
  25         struct device *dev;
  26
  27         dev = class_find_device(fpga_region_class, start, data, match);
  28         if (!dev)
  29                 return NULL;
  30
  31         return to_fpga_region(dev);
  32 }
  33 EXPORT_SYMBOL_GPL(fpga_region_class_find);
  34
  35 /**
  36  * fpga_region_get - get an exclusive reference to a fpga region
  37  * @region: FPGA Region struct
  38  *
  39  * Caller should call fpga_region_put() when done with region.
  40  *
  41  * Return fpga_region struct if successful.
  42  * Return -EBUSY if someone already has a reference to the region.
  43  * Return -ENODEV if @np is not a FPGA Region.
  44  */
  45 static struct fpga_region *fpga_region_get(struct fpga_region *region)
  46 {
  47         struct device *dev = &region->dev;
  48
  49         if (!mutex_trylock(&region->mutex)) {
  50                 dev_dbg(dev, "%s: FPGA Region already in use\n", __func__);
  51                 return ERR_PTR(-EBUSY);
  52         }
  53
  54         get_device(dev);
  55         if (!try_module_get(dev->parent->driver->owner)) {
  56                 put_device(dev);
  57                 mutex_unlock(&region->mutex);
  58                 return ERR_PTR(-ENODEV);
  59         }
  60
  61         dev_dbg(dev, "get\n");
  62
  63         return region;
  64 }
  65
  66 /**
  67  * fpga_region_put - release a reference to a region
  68  *
  69  * @region: FPGA region
  70  */
  71 static void fpga_region_put(struct fpga_region *region)
  72 {
  73         struct device *dev = &region->dev;
  74
  75         dev_dbg(dev, "put\n");
  76
  77         module_put(dev->parent->driver->owner);
  78         put_device(dev);
  79         mutex_unlock(&region->mutex);
  80 }
  81
  82 /**
  83  * fpga_region_program_fpga - program FPGA
  84  *
  85  * @region: FPGA region
  86  *
  87  * Program an FPGA using fpga image info (region->info).
  88  * If the region has a get_bridges function, the exclusive reference for the
  89  * bridges will be held if programming succeeds.  This is intended to prevent
  90  * reprogramming the region until the caller considers it safe to do so.
  91  * The caller will need to call fpga_bridges_put() before attempting to
  92  * reprogram the region.
  93  *
  94  * Return 0 for success or negative error code.
  95  */
  96 int fpga_region_program_fpga(struct fpga_region *region)
  97 {
  98         struct device *dev = &region->dev;
  99         struct fpga_image_info *info = region->info;
 100         int ret;
 101
 102         region = fpga_region_get(region);
 103         if (IS_ERR(region)) {
 104                 dev_err(dev, "failed to get FPGA region\n");
 105                 return PTR_ERR(region);
 106         }
 107
 108         ret = fpga_mgr_lock(region->mgr);
 109         if (ret) {
 110                 dev_err(dev, "FPGA manager is busy\n");
 111                 goto err_put_region;
 112         }
 113
 114         /*
 115          * In some cases, we already have a list of bridges in the
 116          * fpga region struct.  Or we don't have any bridges.
 117          */
 118         if (region->get_bridges) {
 119                 ret = region->get_bridges(region);
 120                 if (ret) {
 121                         dev_err(dev, "failed to get fpga region bridges\n");
 122                         goto err_unlock_mgr;
 123                 }
 124         }
 125
 126         ret = fpga_bridges_disable(&region->bridge_list);
 127         if (ret) {
 128                 dev_err(dev, "failed to disable bridges\n");
 129                 goto err_put_br;
 130         }
 131
 132         ret = fpga_mgr_load(region->mgr, info);
 133         if (ret) {
 134                 dev_err(dev, "failed to load FPGA image\n");
 135                 goto err_put_br;
 136         }
 137
 138         ret = fpga_bridges_enable(&region->bridge_list);
 139         if (ret) {
 140                 dev_err(dev, "failed to enable region bridges\n");
 141                 goto err_put_br;
 142         }
 143
 144         fpga_mgr_unlock(region->mgr);
 145         fpga_region_put(region);
 146
 147         return 0;
 148
 149 err_put_br:
 150         if (region->get_bridges)
 151                 fpga_bridges_put(&region->bridge_list);
 152 err_unlock_mgr:
 153         fpga_mgr_unlock(region->mgr);
 154 err_put_region:
 155         fpga_region_put(region);
 156
 157         return ret;
 158 }
 159 EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
 160
 161 static ssize_t compat_id_show(struct device *dev,
 162                               struct device_attribute *attr, char *buf)
 163 {
 164         struct fpga_region *region = to_fpga_region(dev);
 165
 166         if (!region->compat_id)
 167                 return -ENOENT;
 168
 169         return sprintf(buf, "%016llx%016llx\n",
 170                        (unsigned long long)region->compat_id->id_h,
 171                        (unsigned long long)region->compat_id->id_l);
 172 }
 173
 174 static DEVICE_ATTR_RO(compat_id);
 175
 176 static struct attribute *fpga_region_attrs[] = {
 177         &dev_attr_compat_id.attr,
 178         NULL,
 179 };
 180 ATTRIBUTE_GROUPS(fpga_region);
 181
 182 /**
 183  * fpga_region_create - alloc and init a struct fpga_region
 184  * @dev: device parent
 185  * @mgr: manager that programs this region
 186  * @get_bridges: optional function to get bridges to a list
 187  *
 188  * Return: struct fpga_region or NULL
 189  */
 190 struct fpga_region
 191 *fpga_region_create(struct device *dev,
 192                     struct fpga_manager *mgr,
 193                     int (*get_bridges)(struct fpga_region *))
 194 {
 195         struct fpga_region *region;
 196         int id, ret = 0;
 197
 198         region = kzalloc(sizeof(*region), GFP_KERNEL);
 199         if (!region)
 200                 return NULL;
 201
 202         id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
 203         if (id < 0)
 204                 goto err_free;
 205
 206         region->mgr = mgr;
 207         region->get_bridges = get_bridges;
 208         mutex_init(&region->mutex);
 209         INIT_LIST_HEAD(&region->bridge_list);
 210
 211         device_initialize(&region->dev);
 212         region->dev.class = fpga_region_class;
 213         region->dev.parent = dev;
 214         region->dev.of_node = dev->of_node;
 215         region->dev.id = id;
 216
 217         ret = dev_set_name(&region->dev, "region%d", id);
 218         if (ret)
 219                 goto err_remove;
 220
 221         return region;
 222
 223 err_remove:
 224         ida_simple_remove(&fpga_region_ida, id);
 225 err_free:
 226         kfree(region);
 227
 228         return NULL;
 229 }
 230 EXPORT_SYMBOL_GPL(fpga_region_create);
 231
 232 /**
 233  * fpga_region_free - free a struct fpga_region
 234  * @region: FPGA region created by fpga_region_create
 235  */
 236 void fpga_region_free(struct fpga_region *region)
 237 {
 238         ida_simple_remove(&fpga_region_ida, region->dev.id);
 239         kfree(region);
 240 }
 241 EXPORT_SYMBOL_GPL(fpga_region_free);
 242
 243 /**
 244  * fpga_region_register - register a FPGA region
 245  * @region: FPGA region created by fpga_region_create
 246  * Return: 0 or -errno
 247  */
 248 int fpga_region_register(struct fpga_region *region)
 249 {
 250         return device_add(&region->dev);
 251
 252 }
 253 EXPORT_SYMBOL_GPL(fpga_region_register);
 254
 255 /**
 256  * fpga_region_unregister - unregister and free a FPGA region
 257  * @region: FPGA region
 258  */
 259 void fpga_region_unregister(struct fpga_region *region)
 260 {
 261         device_unregister(&region->dev);
 262 }
 263 EXPORT_SYMBOL_GPL(fpga_region_unregister);
 264
 265 static void fpga_region_dev_release(struct device *dev)
 266 {
 267         struct fpga_region *region = to_fpga_region(dev);
 268
 269         fpga_region_free(region);
 270 }
 271
 272 /**
 273  * fpga_region_init - init function for fpga_region class
 274  * Creates the fpga_region class and registers a reconfig notifier.
 275  */
 276 static int __init fpga_region_init(void)
 277 {
 278         fpga_region_class = class_create(THIS_MODULE, "fpga_region");
 279         if (IS_ERR(fpga_region_class))
 280                 return PTR_ERR(fpga_region_class);
 281
 282         fpga_region_class->dev_groups = fpga_region_groups;
 283         fpga_region_class->dev_release = fpga_region_dev_release;
 284
 285         return 0;
 286 }
 287
 288 static void __exit fpga_region_exit(void)
 289 {
 290         class_destroy(fpga_region_class);
 291         ida_destroy(&fpga_region_ida);
 292 }
 293
 294 subsys_initcall(fpga_region_init);
 295 module_exit(fpga_region_exit);
 296
 297 MODULE_DESCRIPTION("FPGA Region");
 298 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
 299 MODULE_LICENSE("GPL v2");