drivers/staging/greybus/fw-download.c

   1 /*
   2  * Greybus Firmware Download Protocol Driver.
   3  *
   4  * Copyright 2016 Google Inc.
   5  * Copyright 2016 Linaro Ltd.
   6  *
   7  * Released under the GPLv2 only.
   8  */
   9
  10 #include <linux/firmware.h>
  11 #include <linux/jiffies.h>
  12 #include <linux/mutex.h>
  13 #include <linux/workqueue.h>
  14 #include "firmware.h"
  15 #include "greybus.h"
  16
  17 /* Estimated minimum buffer size, actual size can be smaller than this */
  18 #define MIN_FETCH_SIZE          512
  19 /* Timeout, in jiffies, within which fetch or release firmware must be called */
  20 #define NEXT_REQ_TIMEOUT_J      msecs_to_jiffies(1000)
  21
  22 struct fw_request {
  23         u8                      firmware_id;
  24         bool                    disabled;
  25         bool                    timedout;
  26         char                    name[FW_NAME_SIZE];
  27         const struct firmware   *fw;
  28         struct list_head        node;
  29
  30         struct delayed_work     dwork;
  31         /* Timeout, in jiffies, within which the firmware shall download */
  32         unsigned long           release_timeout_j;
  33         struct kref             kref;
  34         struct fw_download      *fw_download;
  35 };
  36
  37 struct fw_download {
  38         struct device           *parent;
  39         struct gb_connection    *connection;
  40         struct list_head        fw_requests;
  41         struct ida              id_map;
  42         struct mutex            mutex;
  43 };
  44
  45 static void fw_req_release(struct kref *kref)
  46 {
  47         struct fw_request *fw_req = container_of(kref, struct fw_request, kref);
  48
  49         dev_dbg(fw_req->fw_download->parent, "firmware %s released\n",
  50                 fw_req->name);
  51
  52         release_firmware(fw_req->fw);
  53
  54         /*
  55          * The request timed out and the module may send a fetch-fw or
  56          * release-fw request later. Lets block the id we allocated for this
  57          * request, so that the AP doesn't refer to a later fw-request (with
  58          * same firmware_id) for the old timedout fw-request.
  59          *
  60          * NOTE:
  61          *
  62          * This also means that after 255 timeouts we will fail to service new
  63          * firmware downloads. But what else can we do in that case anyway? Lets
  64          * just hope that it never happens.
  65          */
  66         if (!fw_req->timedout)
  67                 ida_simple_remove(&fw_req->fw_download->id_map,
  68                                   fw_req->firmware_id);
  69
  70         kfree(fw_req);
  71 }
  72
  73 /*
  74  * Incoming requests are serialized for a connection, and the only race possible
  75  * is between the timeout handler freeing this and an incoming request.
  76  *
  77  * The operations on the fw-request list are protected by the mutex and
  78  * get_fw_req() increments the reference count before returning a fw_req pointer
  79  * to the users.
  80  *
  81  * free_firmware() also takes the mutex while removing an entry from the list,
  82  * it guarantees that every user of fw_req has taken a kref-reference by now and
  83  * we wouldn't have any new users.
  84  *
  85  * Once the last user drops the reference, the fw_req structure is freed.
  86  */
  87 static void put_fw_req(struct fw_request *fw_req)
  88 {
  89         kref_put(&fw_req->kref, fw_req_release);
  90 }
  91
  92 /* Caller must call put_fw_req() after using struct fw_request */
  93 static struct fw_request *get_fw_req(struct fw_download *fw_download,
  94                                      u8 firmware_id)
  95 {
  96         struct fw_request *fw_req;
  97
  98         mutex_lock(&fw_download->mutex);
  99
 100         list_for_each_entry(fw_req, &fw_download->fw_requests, node) {
 101                 if (fw_req->firmware_id == firmware_id) {
 102                         kref_get(&fw_req->kref);
 103                         goto unlock;
 104                 }
 105         }
 106
 107         fw_req = NULL;
 108
 109 unlock:
 110         mutex_unlock(&fw_download->mutex);
 111
 112         return fw_req;
 113 }
 114
 115 static void free_firmware(struct fw_download *fw_download,
 116                           struct fw_request *fw_req)
 117 {
 118         /* Already disabled from timeout handlers */
 119         if (fw_req->disabled)
 120                 return;
 121
 122         mutex_lock(&fw_download->mutex);
 123         list_del(&fw_req->node);
 124         mutex_unlock(&fw_download->mutex);
 125
 126         fw_req->disabled = true;
 127         put_fw_req(fw_req);
 128 }
 129
 130 static void fw_request_timedout(struct work_struct *work)
 131 {
 132         struct delayed_work *dwork = to_delayed_work(work);
 133         struct fw_request *fw_req = container_of(dwork, struct fw_request, dwork);
 134         struct fw_download *fw_download = fw_req->fw_download;
 135
 136         dev_err(fw_download->parent,
 137                 "Timed out waiting for fetch / release firmware requests: %u\n",
 138                 fw_req->firmware_id);
 139
 140         fw_req->timedout = true;
 141         free_firmware(fw_download, fw_req);
 142 }
 143
 144 static int exceeds_release_timeout(struct fw_request *fw_req)
 145 {
 146         struct fw_download *fw_download = fw_req->fw_download;
 147
 148         if (time_before(jiffies, fw_req->release_timeout_j))
 149                 return 0;
 150
 151         dev_err(fw_download->parent,
 152                 "Firmware download didn't finish in time, abort: %d\n",
 153                 fw_req->firmware_id);
 154
 155         fw_req->timedout = true;
 156         free_firmware(fw_download, fw_req);
 157
 158         return -ETIMEDOUT;
 159 }
 160
 161 /* This returns path of the firmware blob on the disk */
 162 static struct fw_request *find_firmware(struct fw_download *fw_download,
 163                                         const char *tag)
 164 {
 165         struct gb_interface *intf = fw_download->connection->bundle->intf;
 166         struct fw_request *fw_req;
 167         int ret, req_count;
 168
 169         fw_req = kzalloc(sizeof(*fw_req), GFP_KERNEL);
 170         if (!fw_req)
 171                 return ERR_PTR(-ENOMEM);
 172
 173         /* Allocate ids from 1 to 255 (u8-max), 0 is an invalid id */
 174         ret = ida_simple_get(&fw_download->id_map, 1, 256, GFP_KERNEL);
 175         if (ret < 0) {
 176                 dev_err(fw_download->parent,
 177                         "failed to allocate firmware id (%d)\n", ret);
 178                 goto err_free_req;
 179         }
 180         fw_req->firmware_id = ret;
 181
 182         snprintf(fw_req->name, sizeof(fw_req->name),
 183                  FW_NAME_PREFIX "%08x_%08x_%08x_%08x_%s.tftf",
 184                  intf->ddbl1_manufacturer_id, intf->ddbl1_product_id,
 185                  intf->vendor_id, intf->product_id, tag);
 186
 187         dev_info(fw_download->parent, "Requested firmware package '%s'\n",
 188                  fw_req->name);
 189
 190         ret = request_firmware(&fw_req->fw, fw_req->name, fw_download->parent);
 191         if (ret) {
 192                 dev_err(fw_download->parent,
 193                         "firmware request failed for %s (%d)\n", fw_req->name,
 194                         ret);
 195                 goto err_free_id;
 196         }
 197
 198         fw_req->fw_download = fw_download;
 199         kref_init(&fw_req->kref);
 200
 201         mutex_lock(&fw_download->mutex);
 202         list_add(&fw_req->node, &fw_download->fw_requests);
 203         mutex_unlock(&fw_download->mutex);
 204
 205         /* Timeout, in jiffies, within which firmware should get loaded */
 206         req_count = DIV_ROUND_UP(fw_req->fw->size, MIN_FETCH_SIZE);
 207         fw_req->release_timeout_j = jiffies + req_count * NEXT_REQ_TIMEOUT_J;
 208
 209         INIT_DELAYED_WORK(&fw_req->dwork, fw_request_timedout);
 210         schedule_delayed_work(&fw_req->dwork, NEXT_REQ_TIMEOUT_J);
 211
 212         return fw_req;
 213
 214 err_free_id:
 215         ida_simple_remove(&fw_download->id_map, fw_req->firmware_id);
 216 err_free_req:
 217         kfree(fw_req);
 218
 219         return ERR_PTR(ret);
 220 }
 221
 222 static int fw_download_find_firmware(struct gb_operation *op)
 223 {
 224         struct gb_connection *connection = op->connection;
 225         struct fw_download *fw_download = gb_connection_get_data(connection);
 226         struct gb_fw_download_find_firmware_request *request;
 227         struct gb_fw_download_find_firmware_response *response;
 228         struct fw_request *fw_req;
 229         const char *tag;
 230
 231         if (op->request->payload_size != sizeof(*request)) {
 232                 dev_err(fw_download->parent,
 233                         "illegal size of find firmware request (%zu != %zu)\n",
 234                         op->request->payload_size, sizeof(*request));
 235                 return -EINVAL;
 236         }
 237
 238         request = op->request->payload;
 239         tag = (const char *)request->firmware_tag;
 240
 241         /* firmware_tag must be null-terminated */
 242         if (strnlen(tag, GB_FIRMWARE_TAG_MAX_SIZE) == GB_FIRMWARE_TAG_MAX_SIZE) {
 243                 dev_err(fw_download->parent,
 244                         "firmware-tag is not null-terminated\n");
 245                 return -EINVAL;
 246         }
 247
 248         fw_req = find_firmware(fw_download, tag);
 249         if (IS_ERR(fw_req))
 250                 return PTR_ERR(fw_req);
 251
 252         if (!gb_operation_response_alloc(op, sizeof(*response), GFP_KERNEL)) {
 253                 dev_err(fw_download->parent, "error allocating response\n");
 254                 free_firmware(fw_download, fw_req);
 255                 return -ENOMEM;
 256         }
 257
 258         response = op->response->payload;
 259         response->firmware_id = fw_req->firmware_id;
 260         response->size = cpu_to_le32(fw_req->fw->size);
 261
 262         dev_dbg(fw_download->parent,
 263                 "firmware size is %zu bytes\n", fw_req->fw->size);
 264
 265         return 0;
 266 }
 267
 268 static int fw_download_fetch_firmware(struct gb_operation *op)
 269 {
 270         struct gb_connection *connection = op->connection;
 271         struct fw_download *fw_download = gb_connection_get_data(connection);
 272         struct gb_fw_download_fetch_firmware_request *request;
 273         struct gb_fw_download_fetch_firmware_response *response;
 274         struct fw_request *fw_req;
 275         const struct firmware *fw;
 276         unsigned int offset, size;
 277         u8 firmware_id;
 278         int ret = 0;
 279
 280         if (op->request->payload_size != sizeof(*request)) {
 281                 dev_err(fw_download->parent,
 282                         "Illegal size of fetch firmware request (%zu %zu)\n",
 283                         op->request->payload_size, sizeof(*request));
 284                 return -EINVAL;
 285         }
 286
 287         request = op->request->payload;
 288         offset = le32_to_cpu(request->offset);
 289         size = le32_to_cpu(request->size);
 290         firmware_id = request->firmware_id;
 291
 292         fw_req = get_fw_req(fw_download, firmware_id);
 293         if (!fw_req) {
 294                 dev_err(fw_download->parent,
 295                         "firmware not available for id: %02u\n", firmware_id);
 296                 return -EINVAL;
 297         }
 298
 299         /* Make sure work handler isn't running in parallel */
 300         cancel_delayed_work_sync(&fw_req->dwork);
 301
 302         /* We timed-out before reaching here ? */
 303         if (fw_req->disabled) {
 304                 ret = -ETIMEDOUT;
 305                 goto put_fw;
 306         }
 307
 308         /*
 309          * Firmware download must finish within a limited time interval. If it
 310          * doesn't, then we might have a buggy Module on the other side. Abort
 311          * download.
 312          */
 313         ret = exceeds_release_timeout(fw_req);
 314         if (ret)
 315                 goto put_fw;
 316
 317         fw = fw_req->fw;
 318
 319         if (offset >= fw->size || size > fw->size - offset) {
 320                 dev_err(fw_download->parent,
 321                         "bad fetch firmware request (offs = %u, size = %u)\n",
 322                         offset, size);
 323                 ret = -EINVAL;
 324                 goto put_fw;
 325         }
 326
 327         if (!gb_operation_response_alloc(op, sizeof(*response) + size,
 328                                          GFP_KERNEL)) {
 329                 dev_err(fw_download->parent,
 330                         "error allocating fetch firmware response\n");
 331                 ret = -ENOMEM;
 332                 goto put_fw;
 333         }
 334
 335         response = op->response->payload;
 336         memcpy(response->data, fw->data + offset, size);
 337
 338         dev_dbg(fw_download->parent,
 339                 "responding with firmware (offs = %u, size = %u)\n", offset,
 340                 size);
 341
 342         /* Refresh timeout */
 343         schedule_delayed_work(&fw_req->dwork, NEXT_REQ_TIMEOUT_J);
 344
 345 put_fw:
 346         put_fw_req(fw_req);
 347
 348         return ret;
 349 }
 350
 351 static int fw_download_release_firmware(struct gb_operation *op)
 352 {
 353         struct gb_connection *connection = op->connection;
 354         struct fw_download *fw_download = gb_connection_get_data(connection);
 355         struct gb_fw_download_release_firmware_request *request;
 356         struct fw_request *fw_req;
 357         u8 firmware_id;
 358
 359         if (op->request->payload_size != sizeof(*request)) {
 360                 dev_err(fw_download->parent,
 361                         "Illegal size of release firmware request (%zu %zu)\n",
 362                         op->request->payload_size, sizeof(*request));
 363                 return -EINVAL;
 364         }
 365
 366         request = op->request->payload;
 367         firmware_id = request->firmware_id;
 368
 369         fw_req = get_fw_req(fw_download, firmware_id);
 370         if (!fw_req) {
 371                 dev_err(fw_download->parent,
 372                         "firmware not available for id: %02u\n", firmware_id);
 373                 return -EINVAL;
 374         }
 375
 376         cancel_delayed_work_sync(&fw_req->dwork);
 377
 378         free_firmware(fw_download, fw_req);
 379         put_fw_req(fw_req);
 380
 381         dev_dbg(fw_download->parent, "release firmware\n");
 382
 383         return 0;
 384 }
 385
 386 int gb_fw_download_request_handler(struct gb_operation *op)
 387 {
 388         u8 type = op->type;
 389
 390         switch (type) {
 391         case GB_FW_DOWNLOAD_TYPE_FIND_FIRMWARE:
 392                 return fw_download_find_firmware(op);
 393         case GB_FW_DOWNLOAD_TYPE_FETCH_FIRMWARE:
 394                 return fw_download_fetch_firmware(op);
 395         case GB_FW_DOWNLOAD_TYPE_RELEASE_FIRMWARE:
 396                 return fw_download_release_firmware(op);
 397         default:
 398                 dev_err(&op->connection->bundle->dev,
 399                         "unsupported request: %u\n", type);
 400                 return -EINVAL;
 401         }
 402 }
 403
 404 int gb_fw_download_connection_init(struct gb_connection *connection)
 405 {
 406         struct fw_download *fw_download;
 407         int ret;
 408
 409         if (!connection)
 410                 return 0;
 411
 412         fw_download = kzalloc(sizeof(*fw_download), GFP_KERNEL);
 413         if (!fw_download)
 414                 return -ENOMEM;
 415
 416         fw_download->parent = &connection->bundle->dev;
 417         INIT_LIST_HEAD(&fw_download->fw_requests);
 418         ida_init(&fw_download->id_map);
 419         gb_connection_set_data(connection, fw_download);
 420         fw_download->connection = connection;
 421         mutex_init(&fw_download->mutex);
 422
 423         ret = gb_connection_enable(connection);
 424         if (ret)
 425                 goto err_destroy_id_map;
 426
 427         return 0;
 428
 429 err_destroy_id_map:
 430         ida_destroy(&fw_download->id_map);
 431         kfree(fw_download);
 432
 433         return ret;
 434 }
 435
 436 void gb_fw_download_connection_exit(struct gb_connection *connection)
 437 {
 438         struct fw_download *fw_download;
 439         struct fw_request *fw_req, *tmp;
 440
 441         if (!connection)
 442                 return;
 443
 444         fw_download = gb_connection_get_data(connection);
 445         gb_connection_disable(fw_download->connection);
 446
 447         /*
 448          * Make sure we have a reference to the pending requests, before they
 449          * are freed from the timeout handler.
 450          */
 451         mutex_lock(&fw_download->mutex);
 452         list_for_each_entry(fw_req, &fw_download->fw_requests, node)
 453                 kref_get(&fw_req->kref);
 454         mutex_unlock(&fw_download->mutex);
 455
 456         /* Release pending firmware packages */
 457         list_for_each_entry_safe(fw_req, tmp, &fw_download->fw_requests, node) {
 458                 cancel_delayed_work_sync(&fw_req->dwork);
 459                 free_firmware(fw_download, fw_req);
 460                 put_fw_req(fw_req);
 461         }
 462
 463         ida_destroy(&fw_download->id_map);
 464         kfree(fw_download);
 465 }