drivers/fpga/fpga-region.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * FPGA Region - 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 const struct class fpga_region_class;
  20
  21 struct fpga_region *
  22 fpga_region_class_find(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 an fpga region
  37  * @region: FPGA Region struct
  38  *
  39  * Caller should call fpga_region_put() when done with region.
  40  *
  41  * Return:
  42  * * fpga_region struct if successful.
  43  * * -EBUSY if someone already has a reference to the region.
  44  * * -ENODEV if can't take parent driver module refcount.
  45  */
  46 static struct fpga_region *fpga_region_get(struct fpga_region *region)
  47 {
  48         struct device *dev = &region->dev;
  49
  50         if (!mutex_trylock(&region->mutex)) {
  51                 dev_dbg(dev, "%s: FPGA Region already in use\n", __func__);
  52                 return ERR_PTR(-EBUSY);
  53         }
  54
  55         get_device(dev);
  56         if (!try_module_get(region->ops_owner)) {
  57                 put_device(dev);
  58                 mutex_unlock(&region->mutex);
  59                 return ERR_PTR(-ENODEV);
  60         }
  61
  62         dev_dbg(dev, "get\n");
  63
  64         return region;
  65 }
  66
  67 /**
  68  * fpga_region_put - release a reference to a region
  69  *
  70  * @region: FPGA region
  71  */
  72 static void fpga_region_put(struct fpga_region *region)
  73 {
  74         struct device *dev = &region->dev;
  75
  76         dev_dbg(dev, "put\n");
  77
  78         module_put(region->ops_owner);
  79         put_device(dev);
  80         mutex_unlock(&region->mutex);
  81 }
  82
  83 /**
  84  * fpga_region_program_fpga - program FPGA
  85  *
  86  * @region: FPGA region
  87  *
  88  * Program an FPGA using fpga image info (region->info).
  89  * If the region has a get_bridges function, the exclusive reference for the
  90  * bridges will be held if programming succeeds.  This is intended to prevent
  91  * reprogramming the region until the caller considers it safe to do so.
  92  * The caller will need to call fpga_bridges_put() before attempting to
  93  * reprogram the region.
  94  *
  95  * Return: 0 for success or negative error code.
  96  */
  97 int fpga_region_program_fpga(struct fpga_region *region)
  98 {
  99         struct device *dev = &region->dev;
 100         struct fpga_image_info *info = region->info;
 101         int ret;
 102
 103         region = fpga_region_get(region);
 104         if (IS_ERR(region)) {
 105                 dev_err(dev, "failed to get FPGA region\n");
 106                 return PTR_ERR(region);
 107         }
 108
 109         ret = fpga_mgr_lock(region->mgr);
 110         if (ret) {
 111                 dev_err(dev, "FPGA manager is busy\n");
 112                 goto err_put_region;
 113         }
 114
 115         /*
 116          * In some cases, we already have a list of bridges in the
 117          * fpga region struct.  Or we don't have any bridges.
 118          */
 119         if (region->get_bridges) {
 120                 ret = region->get_bridges(region);
 121                 if (ret) {
 122                         dev_err(dev, "failed to get fpga region bridges\n");
 123                         goto err_unlock_mgr;
 124                 }
 125         }
 126
 127         ret = fpga_bridges_disable(&region->bridge_list);
 128         if (ret) {
 129                 dev_err(dev, "failed to disable bridges\n");
 130                 goto err_put_br;
 131         }
 132
 133         ret = fpga_mgr_load(region->mgr, info);
 134         if (ret) {
 135                 dev_err(dev, "failed to load FPGA image\n");
 136                 goto err_put_br;
 137         }
 138
 139         ret = fpga_bridges_enable(&region->bridge_list);
 140         if (ret) {
 141                 dev_err(dev, "failed to enable region bridges\n");
 142                 goto err_put_br;
 143         }
 144
 145         fpga_mgr_unlock(region->mgr);
 146         fpga_region_put(region);
 147
 148         return 0;
 149
 150 err_put_br:
 151         if (region->get_bridges)
 152                 fpga_bridges_put(&region->bridge_list);
 153 err_unlock_mgr:
 154         fpga_mgr_unlock(region->mgr);
 155 err_put_region:
 156         fpga_region_put(region);
 157
 158         return ret;
 159 }
 160 EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
 161
 162 static ssize_t compat_id_show(struct device *dev,
 163                               struct device_attribute *attr, char *buf)
 164 {
 165         struct fpga_region *region = to_fpga_region(dev);
 166
 167         if (!region->compat_id)
 168                 return -ENOENT;
 169
 170         return sprintf(buf, "%016llx%016llx\n",
 171                        (unsigned long long)region->compat_id->id_h,
 172                        (unsigned long long)region->compat_id->id_l);
 173 }
 174
 175 static DEVICE_ATTR_RO(compat_id);
 176
 177 static struct attribute *fpga_region_attrs[] = {
 178         &dev_attr_compat_id.attr,
 179         NULL,
 180 };
 181 ATTRIBUTE_GROUPS(fpga_region);
 182
 183 /**
 184  * __fpga_region_register_full - create and register an FPGA Region device
 185  * @parent: device parent
 186  * @info: parameters for FPGA Region
 187  * @owner: module containing the get_bridges function
 188  *
 189  * Return: struct fpga_region or ERR_PTR()
 190  */
 191 struct fpga_region *
 192 __fpga_region_register_full(struct device *parent, const struct fpga_region_info *info,
 193                             struct module *owner)
 194 {
 195         struct fpga_region *region;
 196         int id, ret = 0;
 197
 198         if (!info) {
 199                 dev_err(parent,
 200                         "Attempt to register without required info structure\n");
 201                 return ERR_PTR(-EINVAL);
 202         }
 203
 204         region = kzalloc(sizeof(*region), GFP_KERNEL);
 205         if (!region)
 206                 return ERR_PTR(-ENOMEM);
 207
 208         id = ida_alloc(&fpga_region_ida, GFP_KERNEL);
 209         if (id < 0) {
 210                 ret = id;
 211                 goto err_free;
 212         }
 213
 214         region->mgr = info->mgr;
 215         region->compat_id = info->compat_id;
 216         region->priv = info->priv;
 217         region->get_bridges = info->get_bridges;
 218         region->ops_owner = owner;
 219
 220         mutex_init(&region->mutex);
 221         INIT_LIST_HEAD(&region->bridge_list);
 222
 223         region->dev.class = &fpga_region_class;
 224         region->dev.parent = parent;
 225         region->dev.of_node = parent->of_node;
 226         region->dev.id = id;
 227
 228         ret = dev_set_name(&region->dev, "region%d", id);
 229         if (ret)
 230                 goto err_remove;
 231
 232         ret = device_register(&region->dev);
 233         if (ret) {
 234                 put_device(&region->dev);
 235                 return ERR_PTR(ret);
 236         }
 237
 238         return region;
 239
 240 err_remove:
 241         ida_free(&fpga_region_ida, id);
 242 err_free:
 243         kfree(region);
 244
 245         return ERR_PTR(ret);
 246 }
 247 EXPORT_SYMBOL_GPL(__fpga_region_register_full);
 248
 249 /**
 250  * __fpga_region_register - create and register an FPGA Region device
 251  * @parent: device parent
 252  * @mgr: manager that programs this region
 253  * @get_bridges: optional function to get bridges to a list
 254  * @owner: module containing the get_bridges function
 255  *
 256  * This simple version of the register function should be sufficient for most users.
 257  * The fpga_region_register_full() function is available for users that need to
 258  * pass additional, optional parameters.
 259  *
 260  * Return: struct fpga_region or ERR_PTR()
 261  */
 262 struct fpga_region *
 263 __fpga_region_register(struct device *parent, struct fpga_manager *mgr,
 264                        int (*get_bridges)(struct fpga_region *), struct module *owner)
 265 {
 266         struct fpga_region_info info = { 0 };
 267
 268         info.mgr = mgr;
 269         info.get_bridges = get_bridges;
 270
 271         return __fpga_region_register_full(parent, &info, owner);
 272 }
 273 EXPORT_SYMBOL_GPL(__fpga_region_register);
 274
 275 /**
 276  * fpga_region_unregister - unregister an FPGA region
 277  * @region: FPGA region
 278  *
 279  * This function is intended for use in an FPGA region driver's remove function.
 280  */
 281 void fpga_region_unregister(struct fpga_region *region)
 282 {
 283         device_unregister(&region->dev);
 284 }
 285 EXPORT_SYMBOL_GPL(fpga_region_unregister);
 286
 287 static void fpga_region_dev_release(struct device *dev)
 288 {
 289         struct fpga_region *region = to_fpga_region(dev);
 290
 291         ida_free(&fpga_region_ida, region->dev.id);
 292         kfree(region);
 293 }
 294
 295 static const struct class fpga_region_class = {
 296         .name = "fpga_region",
 297         .dev_groups = fpga_region_groups,
 298         .dev_release = fpga_region_dev_release,
 299 };
 300
 301 /**
 302  * fpga_region_init - creates the fpga_region class.
 303  *
 304  * Return: 0 on success or ERR_PTR() on error.
 305  */
 306 static int __init fpga_region_init(void)
 307 {
 308         return class_register(&fpga_region_class);
 309 }
 310
 311 static void __exit fpga_region_exit(void)
 312 {
 313         class_unregister(&fpga_region_class);
 314         ida_destroy(&fpga_region_ida);
 315 }
 316
 317 subsys_initcall(fpga_region_init);
 318 module_exit(fpga_region_exit);
 319
 320 MODULE_DESCRIPTION("FPGA Region");
 321 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
 322 MODULE_LICENSE("GPL v2");