drivers/firmware/arm_scmi/optee.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2019-2021 Linaro Ltd.
   4  */
   5
   6 #include <linux/io.h>
   7 #include <linux/of.h>
   8 #include <linux/of_address.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/mutex.h>
  12 #include <linux/slab.h>
  13 #include <linux/tee_drv.h>
  14 #include <linux/uuid.h>
  15 #include <uapi/linux/tee.h>
  16
  17 #include "common.h"
  18
  19 #define SCMI_OPTEE_MAX_MSG_SIZE         128
  20
  21 enum scmi_optee_pta_cmd {
  22         /*
  23          * PTA_SCMI_CMD_CAPABILITIES - Get channel capabilities
  24          *
  25          * [out]    value[0].a: Capability bit mask (enum pta_scmi_caps)
  26          * [out]    value[0].b: Extended capabilities or 0
  27          */
  28         PTA_SCMI_CMD_CAPABILITIES = 0,
  29
  30         /*
  31          * PTA_SCMI_CMD_PROCESS_SMT_CHANNEL - Process SCMI message in SMT buffer
  32          *
  33          * [in]     value[0].a: Channel handle
  34          *
  35          * Shared memory used for SCMI message/response exhange is expected
  36          * already identified and bound to channel handle in both SCMI agent
  37          * and SCMI server (OP-TEE) parts.
  38          * The memory uses SMT header to carry SCMI meta-data (protocol ID and
  39          * protocol message ID).
  40          */
  41         PTA_SCMI_CMD_PROCESS_SMT_CHANNEL = 1,
  42
  43         /*
  44          * PTA_SCMI_CMD_PROCESS_SMT_CHANNEL_MESSAGE - Process SMT/SCMI message
  45          *
  46          * [in]     value[0].a: Channel handle
  47          * [in/out] memref[1]: Message/response buffer (SMT and SCMI payload)
  48          *
  49          * Shared memory used for SCMI message/response is a SMT buffer
  50          * referenced by param[1]. It shall be 128 bytes large to fit response
  51          * payload whatever message playload size.
  52          * The memory uses SMT header to carry SCMI meta-data (protocol ID and
  53          * protocol message ID).
  54          */
  55         PTA_SCMI_CMD_PROCESS_SMT_CHANNEL_MESSAGE = 2,
  56
  57         /*
  58          * PTA_SCMI_CMD_GET_CHANNEL - Get channel handle
  59          *
  60          * SCMI shm information are 0 if agent expects to use OP-TEE regular SHM
  61          *
  62          * [in]     value[0].a: Channel identifier
  63          * [out]    value[0].a: Returned channel handle
  64          * [in]     value[0].b: Requested capabilities mask (enum pta_scmi_caps)
  65          */
  66         PTA_SCMI_CMD_GET_CHANNEL = 3,
  67
  68         /*
  69          * PTA_SCMI_CMD_PROCESS_MSG_CHANNEL - Process SCMI message in a MSG
  70          * buffer pointed by memref parameters
  71          *
  72          * [in]     value[0].a: Channel handle
  73          * [in]     memref[1]: Message buffer (MSG and SCMI payload)
  74          * [out]    memref[2]: Response buffer (MSG and SCMI payload)
  75          *
  76          * Shared memories used for SCMI message/response are MSG buffers
  77          * referenced by param[1] and param[2]. MSG transport protocol
  78          * uses a 32bit header to carry SCMI meta-data (protocol ID and
  79          * protocol message ID) followed by the effective SCMI message
  80          * payload.
  81          */
  82         PTA_SCMI_CMD_PROCESS_MSG_CHANNEL = 4,
  83 };
  84
  85 /*
  86  * OP-TEE SCMI service capabilities bit flags (32bit)
  87  *
  88  * PTA_SCMI_CAPS_SMT_HEADER
  89  * When set, OP-TEE supports command using SMT header protocol (SCMI shmem) in
  90  * shared memory buffers to carry SCMI protocol synchronisation information.
  91  *
  92  * PTA_SCMI_CAPS_MSG_HEADER
  93  * When set, OP-TEE supports command using MSG header protocol in an OP-TEE
  94  * shared memory to carry SCMI protocol synchronisation information and SCMI
  95  * message payload.
  96  */
  97 #define PTA_SCMI_CAPS_NONE              0
  98 #define PTA_SCMI_CAPS_SMT_HEADER        BIT(0)
  99 #define PTA_SCMI_CAPS_MSG_HEADER        BIT(1)
 100 #define PTA_SCMI_CAPS_MASK              (PTA_SCMI_CAPS_SMT_HEADER | \
 101                                          PTA_SCMI_CAPS_MSG_HEADER)
 102
 103 /**
 104  * struct scmi_optee_channel - Description of an OP-TEE SCMI channel
 105  *
 106  * @channel_id: OP-TEE channel ID used for this transport
 107  * @tee_session: TEE session identifier
 108  * @caps: OP-TEE SCMI channel capabilities
 109  * @rx_len: Response size
 110  * @mu: Mutex protection on channel access
 111  * @cinfo: SCMI channel information
 112  * @shmem: Virtual base address of the shared memory
 113  * @req: Shared memory protocol handle for SCMI request and synchronous response
 114  * @tee_shm: TEE shared memory handle @req or NULL if using IOMEM shmem
 115  * @link: Reference in agent's channel list
 116  */
 117 struct scmi_optee_channel {
 118         u32 channel_id;
 119         u32 tee_session;
 120         u32 caps;
 121         u32 rx_len;
 122         struct mutex mu;
 123         struct scmi_chan_info *cinfo;
 124         union {
 125                 struct scmi_shared_mem __iomem *shmem;
 126                 struct scmi_msg_payld *msg;
 127         } req;
 128         struct tee_shm *tee_shm;
 129         struct list_head link;
 130 };
 131
 132 /**
 133  * struct scmi_optee_agent - OP-TEE transport private data
 134  *
 135  * @dev: Device used for communication with TEE
 136  * @tee_ctx: TEE context used for communication
 137  * @caps: Supported channel capabilities
 138  * @mu: Mutex for protection of @channel_list
 139  * @channel_list: List of all created channels for the agent
 140  */
 141 struct scmi_optee_agent {
 142         struct device *dev;
 143         struct tee_context *tee_ctx;
 144         u32 caps;
 145         struct mutex mu;
 146         struct list_head channel_list;
 147 };
 148
 149 /* There can be only 1 SCMI service in OP-TEE we connect to */
 150 static struct scmi_optee_agent *scmi_optee_private;
 151
 152 /* Forward reference to scmi_optee transport initialization */
 153 static int scmi_optee_init(void);
 154
 155 /* Open a session toward SCMI OP-TEE service with REE_KERNEL identity */
 156 static int open_session(struct scmi_optee_agent *agent, u32 *tee_session)
 157 {
 158         struct device *dev = agent->dev;
 159         struct tee_client_device *scmi_pta = to_tee_client_device(dev);
 160         struct tee_ioctl_open_session_arg arg = { };
 161         int ret;
 162
 163         memcpy(arg.uuid, scmi_pta->id.uuid.b, TEE_IOCTL_UUID_LEN);
 164         arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
 165
 166         ret = tee_client_open_session(agent->tee_ctx, &arg, NULL);
 167         if (ret < 0 || arg.ret) {
 168                 dev_err(dev, "Can't open tee session: %d / %#x\n", ret, arg.ret);
 169                 return -EOPNOTSUPP;
 170         }
 171
 172         *tee_session = arg.session;
 173
 174         return 0;
 175 }
 176
 177 static void close_session(struct scmi_optee_agent *agent, u32 tee_session)
 178 {
 179         tee_client_close_session(agent->tee_ctx, tee_session);
 180 }
 181
 182 static int get_capabilities(struct scmi_optee_agent *agent)
 183 {
 184         struct tee_ioctl_invoke_arg arg = { };
 185         struct tee_param param[1] = { };
 186         u32 caps;
 187         u32 tee_session;
 188         int ret;
 189
 190         ret = open_session(agent, &tee_session);
 191         if (ret)
 192                 return ret;
 193
 194         arg.func = PTA_SCMI_CMD_CAPABILITIES;
 195         arg.session = tee_session;
 196         arg.num_params = 1;
 197
 198         param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
 199
 200         ret = tee_client_invoke_func(agent->tee_ctx, &arg, param);
 201
 202         close_session(agent, tee_session);
 203
 204         if (ret < 0 || arg.ret) {
 205                 dev_err(agent->dev, "Can't get capabilities: %d / %#x\n", ret, arg.ret);
 206                 return -EOPNOTSUPP;
 207         }
 208
 209         caps = param[0].u.value.a;
 210
 211         if (!(caps & (PTA_SCMI_CAPS_SMT_HEADER | PTA_SCMI_CAPS_MSG_HEADER))) {
 212                 dev_err(agent->dev, "OP-TEE SCMI PTA doesn't support SMT and MSG\n");
 213                 return -EOPNOTSUPP;
 214         }
 215
 216         agent->caps = caps;
 217
 218         return 0;
 219 }
 220
 221 static int get_channel(struct scmi_optee_channel *channel)
 222 {
 223         struct device *dev = scmi_optee_private->dev;
 224         struct tee_ioctl_invoke_arg arg = { };
 225         struct tee_param param[1] = { };
 226         unsigned int caps = 0;
 227         int ret;
 228
 229         if (channel->tee_shm)
 230                 caps = PTA_SCMI_CAPS_MSG_HEADER;
 231         else
 232                 caps = PTA_SCMI_CAPS_SMT_HEADER;
 233
 234         arg.func = PTA_SCMI_CMD_GET_CHANNEL;
 235         arg.session = channel->tee_session;
 236         arg.num_params = 1;
 237
 238         param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT;
 239         param[0].u.value.a = channel->channel_id;
 240         param[0].u.value.b = caps;
 241
 242         ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
 243
 244         if (ret || arg.ret) {
 245                 dev_err(dev, "Can't get channel with caps %#x: %d / %#x\n", caps, ret, arg.ret);
 246                 return -EOPNOTSUPP;
 247         }
 248
 249         /* From now on use channel identifer provided by OP-TEE SCMI service */
 250         channel->channel_id = param[0].u.value.a;
 251         channel->caps = caps;
 252
 253         return 0;
 254 }
 255
 256 static int invoke_process_smt_channel(struct scmi_optee_channel *channel)
 257 {
 258         struct tee_ioctl_invoke_arg arg = {
 259                 .func = PTA_SCMI_CMD_PROCESS_SMT_CHANNEL,
 260                 .session = channel->tee_session,
 261                 .num_params = 1,
 262         };
 263         struct tee_param param[1] = { };
 264         int ret;
 265
 266         param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
 267         param[0].u.value.a = channel->channel_id;
 268
 269         ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
 270         if (ret < 0 || arg.ret) {
 271                 dev_err(scmi_optee_private->dev, "Can't invoke channel %u: %d / %#x\n",
 272                         channel->channel_id, ret, arg.ret);
 273                 return -EIO;
 274         }
 275
 276         return 0;
 277 }
 278
 279 static int invoke_process_msg_channel(struct scmi_optee_channel *channel, size_t msg_size)
 280 {
 281         struct tee_ioctl_invoke_arg arg = {
 282                 .func = PTA_SCMI_CMD_PROCESS_MSG_CHANNEL,
 283                 .session = channel->tee_session,
 284                 .num_params = 3,
 285         };
 286         struct tee_param param[3] = { };
 287         int ret;
 288
 289         param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT;
 290         param[0].u.value.a = channel->channel_id;
 291
 292         param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT;
 293         param[1].u.memref.shm = channel->tee_shm;
 294         param[1].u.memref.size = msg_size;
 295
 296         param[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT;
 297         param[2].u.memref.shm = channel->tee_shm;
 298         param[2].u.memref.size = SCMI_OPTEE_MAX_MSG_SIZE;
 299
 300         ret = tee_client_invoke_func(scmi_optee_private->tee_ctx, &arg, param);
 301         if (ret < 0 || arg.ret) {
 302                 dev_err(scmi_optee_private->dev, "Can't invoke channel %u: %d / %#x\n",
 303                         channel->channel_id, ret, arg.ret);
 304                 return -EIO;
 305         }
 306
 307         /* Save response size */
 308         channel->rx_len = param[2].u.memref.size;
 309
 310         return 0;
 311 }
 312
 313 static int scmi_optee_link_supplier(struct device *dev)
 314 {
 315         if (!scmi_optee_private) {
 316                 if (scmi_optee_init())
 317                         dev_dbg(dev, "Optee bus not yet ready\n");
 318
 319                 /* Wait for optee bus */
 320                 return -EPROBE_DEFER;
 321         }
 322
 323         if (!device_link_add(dev, scmi_optee_private->dev, DL_FLAG_AUTOREMOVE_CONSUMER)) {
 324                 dev_err(dev, "Adding link to supplier optee device failed\n");
 325                 return -ECANCELED;
 326         }
 327
 328         return 0;
 329 }
 330
 331 static bool scmi_optee_chan_available(struct device_node *of_node, int idx)
 332 {
 333         u32 channel_id;
 334
 335         return !of_property_read_u32_index(of_node, "linaro,optee-channel-id",
 336                                            idx, &channel_id);
 337 }
 338
 339 static void scmi_optee_clear_channel(struct scmi_chan_info *cinfo)
 340 {
 341         struct scmi_optee_channel *channel = cinfo->transport_info;
 342
 343         if (!channel->tee_shm)
 344                 shmem_clear_channel(channel->req.shmem);
 345 }
 346
 347 static int setup_dynamic_shmem(struct device *dev, struct scmi_optee_channel *channel)
 348 {
 349         const size_t msg_size = SCMI_OPTEE_MAX_MSG_SIZE;
 350         void *shbuf;
 351
 352         channel->tee_shm = tee_shm_alloc_kernel_buf(scmi_optee_private->tee_ctx, msg_size);
 353         if (IS_ERR(channel->tee_shm)) {
 354                 dev_err(channel->cinfo->dev, "shmem allocation failed\n");
 355                 return -ENOMEM;
 356         }
 357
 358         shbuf = tee_shm_get_va(channel->tee_shm, 0);
 359         memset(shbuf, 0, msg_size);
 360         channel->req.msg = shbuf;
 361         channel->rx_len = msg_size;
 362
 363         return 0;
 364 }
 365
 366 static int setup_static_shmem(struct device *dev, struct scmi_chan_info *cinfo,
 367                               struct scmi_optee_channel *channel)
 368 {
 369         struct device_node *np;
 370         resource_size_t size;
 371         struct resource res;
 372         int ret;
 373
 374         np = of_parse_phandle(cinfo->dev->of_node, "shmem", 0);
 375         if (!of_device_is_compatible(np, "arm,scmi-shmem")) {
 376                 ret = -ENXIO;
 377                 goto out;
 378         }
 379
 380         ret = of_address_to_resource(np, 0, &res);
 381         if (ret) {
 382                 dev_err(dev, "Failed to get SCMI Tx shared memory\n");
 383                 goto out;
 384         }
 385
 386         size = resource_size(&res);
 387
 388         channel->req.shmem = devm_ioremap(dev, res.start, size);
 389         if (!channel->req.shmem) {
 390                 dev_err(dev, "Failed to ioremap SCMI Tx shared memory\n");
 391                 ret = -EADDRNOTAVAIL;
 392                 goto out;
 393         }
 394
 395         ret = 0;
 396
 397 out:
 398         of_node_put(np);
 399
 400         return ret;
 401 }
 402
 403 static int setup_shmem(struct device *dev, struct scmi_chan_info *cinfo,
 404                        struct scmi_optee_channel *channel)
 405 {
 406         if (of_property_present(cinfo->dev->of_node, "shmem"))
 407                 return setup_static_shmem(dev, cinfo, channel);
 408         else
 409                 return setup_dynamic_shmem(dev, channel);
 410 }
 411
 412 static int scmi_optee_chan_setup(struct scmi_chan_info *cinfo, struct device *dev, bool tx)
 413 {
 414         struct scmi_optee_channel *channel;
 415         uint32_t channel_id;
 416         int ret;
 417
 418         if (!tx)
 419                 return -ENODEV;
 420
 421         channel = devm_kzalloc(dev, sizeof(*channel), GFP_KERNEL);
 422         if (!channel)
 423                 return -ENOMEM;
 424
 425         ret = of_property_read_u32_index(cinfo->dev->of_node, "linaro,optee-channel-id",
 426                                          0, &channel_id);
 427         if (ret)
 428                 return ret;
 429
 430         cinfo->transport_info = channel;
 431         channel->cinfo = cinfo;
 432         channel->channel_id = channel_id;
 433         mutex_init(&channel->mu);
 434
 435         ret = setup_shmem(dev, cinfo, channel);
 436         if (ret)
 437                 return ret;
 438
 439         ret = open_session(scmi_optee_private, &channel->tee_session);
 440         if (ret)
 441                 goto err_free_shm;
 442
 443         ret = get_channel(channel);
 444         if (ret)
 445                 goto err_close_sess;
 446
 447         /* Enable polling */
 448         cinfo->no_completion_irq = true;
 449
 450         mutex_lock(&scmi_optee_private->mu);
 451         list_add(&channel->link, &scmi_optee_private->channel_list);
 452         mutex_unlock(&scmi_optee_private->mu);
 453
 454         return 0;
 455
 456 err_close_sess:
 457         close_session(scmi_optee_private, channel->tee_session);
 458 err_free_shm:
 459         if (channel->tee_shm)
 460                 tee_shm_free(channel->tee_shm);
 461
 462         return ret;
 463 }
 464
 465 static int scmi_optee_chan_free(int id, void *p, void *data)
 466 {
 467         struct scmi_chan_info *cinfo = p;
 468         struct scmi_optee_channel *channel = cinfo->transport_info;
 469
 470         mutex_lock(&scmi_optee_private->mu);
 471         list_del(&channel->link);
 472         mutex_unlock(&scmi_optee_private->mu);
 473
 474         close_session(scmi_optee_private, channel->tee_session);
 475
 476         if (channel->tee_shm) {
 477                 tee_shm_free(channel->tee_shm);
 478                 channel->tee_shm = NULL;
 479         }
 480
 481         cinfo->transport_info = NULL;
 482         channel->cinfo = NULL;
 483
 484         return 0;
 485 }
 486
 487 static int scmi_optee_send_message(struct scmi_chan_info *cinfo,
 488                                    struct scmi_xfer *xfer)
 489 {
 490         struct scmi_optee_channel *channel = cinfo->transport_info;
 491         int ret;
 492
 493         mutex_lock(&channel->mu);
 494
 495         if (channel->tee_shm) {
 496                 msg_tx_prepare(channel->req.msg, xfer);
 497                 ret = invoke_process_msg_channel(channel, msg_command_size(xfer));
 498         } else {
 499                 shmem_tx_prepare(channel->req.shmem, xfer, cinfo);
 500                 ret = invoke_process_smt_channel(channel);
 501         }
 502
 503         if (ret)
 504                 mutex_unlock(&channel->mu);
 505
 506         return ret;
 507 }
 508
 509 static void scmi_optee_fetch_response(struct scmi_chan_info *cinfo,
 510                                       struct scmi_xfer *xfer)
 511 {
 512         struct scmi_optee_channel *channel = cinfo->transport_info;
 513
 514         if (channel->tee_shm)
 515                 msg_fetch_response(channel->req.msg, channel->rx_len, xfer);
 516         else
 517                 shmem_fetch_response(channel->req.shmem, xfer);
 518 }
 519
 520 static void scmi_optee_mark_txdone(struct scmi_chan_info *cinfo, int ret,
 521                                    struct scmi_xfer *__unused)
 522 {
 523         struct scmi_optee_channel *channel = cinfo->transport_info;
 524
 525         mutex_unlock(&channel->mu);
 526 }
 527
 528 static struct scmi_transport_ops scmi_optee_ops = {
 529         .link_supplier = scmi_optee_link_supplier,
 530         .chan_available = scmi_optee_chan_available,
 531         .chan_setup = scmi_optee_chan_setup,
 532         .chan_free = scmi_optee_chan_free,
 533         .send_message = scmi_optee_send_message,
 534         .mark_txdone = scmi_optee_mark_txdone,
 535         .fetch_response = scmi_optee_fetch_response,
 536         .clear_channel = scmi_optee_clear_channel,
 537 };
 538
 539 static int scmi_optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
 540 {
 541         return ver->impl_id == TEE_IMPL_ID_OPTEE;
 542 }
 543
 544 static int scmi_optee_service_probe(struct device *dev)
 545 {
 546         struct scmi_optee_agent *agent;
 547         struct tee_context *tee_ctx;
 548         int ret;
 549
 550         /* Only one SCMI OP-TEE device allowed */
 551         if (scmi_optee_private) {
 552                 dev_err(dev, "An SCMI OP-TEE device was already initialized: only one allowed\n");
 553                 return -EBUSY;
 554         }
 555
 556         tee_ctx = tee_client_open_context(NULL, scmi_optee_ctx_match, NULL, NULL);
 557         if (IS_ERR(tee_ctx))
 558                 return -ENODEV;
 559
 560         agent = devm_kzalloc(dev, sizeof(*agent), GFP_KERNEL);
 561         if (!agent) {
 562                 ret = -ENOMEM;
 563                 goto err;
 564         }
 565
 566         agent->dev = dev;
 567         agent->tee_ctx = tee_ctx;
 568         INIT_LIST_HEAD(&agent->channel_list);
 569         mutex_init(&agent->mu);
 570
 571         ret = get_capabilities(agent);
 572         if (ret)
 573                 goto err;
 574
 575         /* Ensure agent resources are all visible before scmi_optee_private is */
 576         smp_mb();
 577         scmi_optee_private = agent;
 578
 579         return 0;
 580
 581 err:
 582         tee_client_close_context(tee_ctx);
 583
 584         return ret;
 585 }
 586
 587 static int scmi_optee_service_remove(struct device *dev)
 588 {
 589         struct scmi_optee_agent *agent = scmi_optee_private;
 590
 591         if (!scmi_optee_private)
 592                 return -EINVAL;
 593
 594         if (!list_empty(&scmi_optee_private->channel_list))
 595                 return -EBUSY;
 596
 597         /* Ensure cleared reference is visible before resources are released */
 598         smp_store_mb(scmi_optee_private, NULL);
 599
 600         tee_client_close_context(agent->tee_ctx);
 601
 602         return 0;
 603 }
 604
 605 static const struct tee_client_device_id scmi_optee_service_id[] = {
 606         {
 607                 UUID_INIT(0xa8cfe406, 0xd4f5, 0x4a2e,
 608                           0x9f, 0x8d, 0xa2, 0x5d, 0xc7, 0x54, 0xc0, 0x99)
 609         },
 610         { }
 611 };
 612
 613 MODULE_DEVICE_TABLE(tee, scmi_optee_service_id);
 614
 615 static struct tee_client_driver scmi_optee_driver = {
 616         .id_table       = scmi_optee_service_id,
 617         .driver         = {
 618                 .name = "scmi-optee",
 619                 .bus = &tee_bus_type,
 620                 .probe = scmi_optee_service_probe,
 621                 .remove = scmi_optee_service_remove,
 622         },
 623 };
 624
 625 static int scmi_optee_init(void)
 626 {
 627         return driver_register(&scmi_optee_driver.driver);
 628 }
 629
 630 static void scmi_optee_exit(void)
 631 {
 632         if (scmi_optee_private)
 633                 driver_unregister(&scmi_optee_driver.driver);
 634 }
 635
 636 const struct scmi_desc scmi_optee_desc = {
 637         .transport_exit = scmi_optee_exit,
 638         .ops = &scmi_optee_ops,
 639         .max_rx_timeout_ms = 30,
 640         .max_msg = 20,
 641         .max_msg_size = SCMI_OPTEE_MAX_MSG_SIZE,
 642         .sync_cmds_completed_on_ret = true,
 643 };