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 /**
 162  * fpga_region_create - alloc and init a struct fpga_region
 163  * @dev: device parent
 164  * @mgr: manager that programs this region
 165  * @get_bridges: optional function to get bridges to a list
 166  *
 167  * Return: struct fpga_region or NULL
 168  */
 169 struct fpga_region
 170 *fpga_region_create(struct device *dev,
 171                     struct fpga_manager *mgr,
 172                     int (*get_bridges)(struct fpga_region *))
 173 {
 174         struct fpga_region *region;
 175         int id, ret = 0;
 176
 177         region = kzalloc(sizeof(*region), GFP_KERNEL);
 178         if (!region)
 179                 return NULL;
 180
 181         id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
 182         if (id < 0)
 183                 goto err_free;
 184
 185         region->mgr = mgr;
 186         region->get_bridges = get_bridges;
 187         mutex_init(&region->mutex);
 188         INIT_LIST_HEAD(&region->bridge_list);
 189
 190         device_initialize(&region->dev);
 191         region->dev.class = fpga_region_class;
 192         region->dev.parent = dev;
 193         region->dev.of_node = dev->of_node;
 194         region->dev.id = id;
 195
 196         ret = dev_set_name(&region->dev, "region%d", id);
 197         if (ret)
 198                 goto err_remove;
 199
 200         return region;
 201
 202 err_remove:
 203         ida_simple_remove(&fpga_region_ida, id);
 204 err_free:
 205         kfree(region);
 206
 207         return NULL;
 208 }
 209 EXPORT_SYMBOL_GPL(fpga_region_create);
 210
 211 /**
 212  * fpga_region_free - free a struct fpga_region
 213  * @region: FPGA region created by fpga_region_create
 214  */
 215 void fpga_region_free(struct fpga_region *region)
 216 {
 217         ida_simple_remove(&fpga_region_ida, region->dev.id);
 218         kfree(region);
 219 }
 220 EXPORT_SYMBOL_GPL(fpga_region_free);
 221
 222 /**
 223  * fpga_region_register - register a FPGA region
 224  * @region: FPGA region created by fpga_region_create
 225  * Return: 0 or -errno
 226  */
 227 int fpga_region_register(struct fpga_region *region)
 228 {
 229         return device_add(&region->dev);
 230
 231 }
 232 EXPORT_SYMBOL_GPL(fpga_region_register);
 233
 234 /**
 235  * fpga_region_unregister - unregister and free a FPGA region
 236  * @region: FPGA region
 237  */
 238 void fpga_region_unregister(struct fpga_region *region)
 239 {
 240         device_unregister(&region->dev);
 241 }
 242 EXPORT_SYMBOL_GPL(fpga_region_unregister);
 243
 244 static void fpga_region_dev_release(struct device *dev)
 245 {
 246         struct fpga_region *region = to_fpga_region(dev);
 247
 248         fpga_region_free(region);
 249 }
 250
 251 /**
 252  * fpga_region_init - init function for fpga_region class
 253  * Creates the fpga_region class and registers a reconfig notifier.
 254  */
 255 static int __init fpga_region_init(void)
 256 {
 257         fpga_region_class = class_create(THIS_MODULE, "fpga_region");
 258         if (IS_ERR(fpga_region_class))
 259                 return PTR_ERR(fpga_region_class);
 260
 261         fpga_region_class->dev_release = fpga_region_dev_release;
 262
 263         return 0;
 264 }
 265
 266 static void __exit fpga_region_exit(void)
 267 {
 268         class_destroy(fpga_region_class);
 269         ida_destroy(&fpga_region_ida);
 270 }
 271
 272 subsys_initcall(fpga_region_init);
 273 module_exit(fpga_region_exit);
 274
 275 MODULE_DESCRIPTION("FPGA Region");
 276 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
 277 MODULE_LICENSE("GPL v2");