drivers/char/tpm/tpm_crb.c

   1 /*
   2  * Copyright (C) 2014 Intel Corporation
   3  *
   4  * Authors:
   5  * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
   6  *
   7  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
   8  *
   9  * This device driver implements the TPM interface as defined in
  10  * the TCG CRB 2.0 TPM specification.
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; version 2
  15  * of the License.
  16  */
  17
  18 #include <linux/acpi.h>
  19 #include <linux/highmem.h>
  20 #include <linux/rculist.h>
  21 #include <linux/module.h>
  22 #include <linux/pm_runtime.h>
  23 #include "tpm.h"
  24
  25 #define ACPI_SIG_TPM2 "TPM2"
  26
  27 static const u8 CRB_ACPI_START_UUID[] = {
  28         /* 0000 */ 0xAB, 0x6C, 0xBF, 0x6B, 0x63, 0x54, 0x14, 0x47,
  29         /* 0008 */ 0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4
  30 };
  31
  32 enum crb_defaults {
  33         CRB_ACPI_START_REVISION_ID = 1,
  34         CRB_ACPI_START_INDEX = 1,
  35 };
  36
  37 enum crb_ctrl_req {
  38         CRB_CTRL_REQ_CMD_READY  = BIT(0),
  39         CRB_CTRL_REQ_GO_IDLE    = BIT(1),
  40 };
  41
  42 enum crb_ctrl_sts {
  43         CRB_CTRL_STS_ERROR      = BIT(0),
  44         CRB_CTRL_STS_TPM_IDLE   = BIT(1),
  45 };
  46
  47 enum crb_start {
  48         CRB_START_INVOKE        = BIT(0),
  49 };
  50
  51 enum crb_cancel {
  52         CRB_CANCEL_INVOKE       = BIT(0),
  53 };
  54
  55 struct crb_control_area {
  56         u32 req;
  57         u32 sts;
  58         u32 cancel;
  59         u32 start;
  60         u32 int_enable;
  61         u32 int_sts;
  62         u32 cmd_size;
  63         u32 cmd_pa_low;
  64         u32 cmd_pa_high;
  65         u32 rsp_size;
  66         u64 rsp_pa;
  67 } __packed;
  68
  69 enum crb_status {
  70         CRB_DRV_STS_COMPLETE    = BIT(0),
  71 };
  72
  73 enum crb_flags {
  74         CRB_FL_ACPI_START       = BIT(0),
  75         CRB_FL_CRB_START        = BIT(1),
  76 };
  77
  78 struct crb_priv {
  79         unsigned int flags;
  80         void __iomem *iobase;
  81         struct crb_control_area __iomem *cca;
  82         u8 __iomem *cmd;
  83         u8 __iomem *rsp;
  84         u32 cmd_size;
  85 };
  86
  87 /**
  88  * crb_go_idle - request tpm crb device to go the idle state
  89  *
  90  * @dev:  crb device
  91  * @priv: crb private data
  92  *
  93  * Write CRB_CTRL_REQ_GO_IDLE to TPM_CRB_CTRL_REQ
  94  * The device should respond within TIMEOUT_C by clearing the bit.
  95  * Anyhow, we do not wait here as a consequent CMD_READY request
  96  * will be handled correctly even if idle was not completed.
  97  *
  98  * The function does nothing for devices with ACPI-start method.
  99  *
 100  * Return: 0 always
 101  */
 102 static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv)
 103 {
 104         if (priv->flags & CRB_FL_ACPI_START)
 105                 return 0;
 106
 107         iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->cca->req);
 108         /* we don't really care when this settles */
 109
 110         return 0;
 111 }
 112
 113 /**
 114  * crb_cmd_ready - request tpm crb device to enter ready state
 115  *
 116  * @dev:  crb device
 117  * @priv: crb private data
 118  *
 119  * Write CRB_CTRL_REQ_CMD_READY to TPM_CRB_CTRL_REQ
 120  * and poll till the device acknowledge it by clearing the bit.
 121  * The device should respond within TIMEOUT_C.
 122  *
 123  * The function does nothing for devices with ACPI-start method
 124  *
 125  * Return: 0 on success -ETIME on timeout;
 126  */
 127 static int __maybe_unused crb_cmd_ready(struct device *dev,
 128                                         struct crb_priv *priv)
 129 {
 130         ktime_t stop, start;
 131
 132         if (priv->flags & CRB_FL_ACPI_START)
 133                 return 0;
 134
 135         iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->cca->req);
 136
 137         start = ktime_get();
 138         stop = ktime_add(start, ms_to_ktime(TPM2_TIMEOUT_C));
 139         do {
 140                 if (!(ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY))
 141                         return 0;
 142                 usleep_range(50, 100);
 143         } while (ktime_before(ktime_get(), stop));
 144
 145         if (ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY) {
 146                 dev_warn(dev, "cmdReady timed out\n");
 147                 return -ETIME;
 148         }
 149
 150         return 0;
 151 }
 152
 153 static u8 crb_status(struct tpm_chip *chip)
 154 {
 155         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 156         u8 sts = 0;
 157
 158         if ((ioread32(&priv->cca->start) & CRB_START_INVOKE) !=
 159             CRB_START_INVOKE)
 160                 sts |= CRB_DRV_STS_COMPLETE;
 161
 162         return sts;
 163 }
 164
 165 static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 166 {
 167         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 168         unsigned int expected;
 169
 170         /* sanity check */
 171         if (count < 6)
 172                 return -EIO;
 173
 174         if (ioread32(&priv->cca->sts) & CRB_CTRL_STS_ERROR)
 175                 return -EIO;
 176
 177         memcpy_fromio(buf, priv->rsp, 6);
 178         expected = be32_to_cpup((__be32 *) &buf[2]);
 179
 180         if (expected > count)
 181                 return -EIO;
 182
 183         memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
 184
 185         return expected;
 186 }
 187
 188 static int crb_do_acpi_start(struct tpm_chip *chip)
 189 {
 190         union acpi_object *obj;
 191         int rc;
 192
 193         obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
 194                                 CRB_ACPI_START_UUID,
 195                                 CRB_ACPI_START_REVISION_ID,
 196                                 CRB_ACPI_START_INDEX,
 197                                 NULL);
 198         if (!obj)
 199                 return -ENXIO;
 200         rc = obj->integer.value == 0 ? 0 : -ENXIO;
 201         ACPI_FREE(obj);
 202         return rc;
 203 }
 204
 205 static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 206 {
 207         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 208         int rc = 0;
 209
 210         /* Zero the cancel register so that the next command will not get
 211          * canceled.
 212          */
 213         iowrite32(0, &priv->cca->cancel);
 214
 215         if (len > priv->cmd_size) {
 216                 dev_err(&chip->dev, "invalid command count value %zd %d\n",
 217                         len, priv->cmd_size);
 218                 return -E2BIG;
 219         }
 220
 221         memcpy_toio(priv->cmd, buf, len);
 222
 223         /* Make sure that cmd is populated before issuing start. */
 224         wmb();
 225
 226         if (priv->flags & CRB_FL_CRB_START)
 227                 iowrite32(CRB_START_INVOKE, &priv->cca->start);
 228
 229         if (priv->flags & CRB_FL_ACPI_START)
 230                 rc = crb_do_acpi_start(chip);
 231
 232         return rc;
 233 }
 234
 235 static void crb_cancel(struct tpm_chip *chip)
 236 {
 237         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 238
 239         iowrite32(CRB_CANCEL_INVOKE, &priv->cca->cancel);
 240
 241         if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip))
 242                 dev_err(&chip->dev, "ACPI Start failed\n");
 243 }
 244
 245 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
 246 {
 247         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 248         u32 cancel = ioread32(&priv->cca->cancel);
 249
 250         return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
 251 }
 252
 253 static const struct tpm_class_ops tpm_crb = {
 254         .flags = TPM_OPS_AUTO_STARTUP,
 255         .status = crb_status,
 256         .recv = crb_recv,
 257         .send = crb_send,
 258         .cancel = crb_cancel,
 259         .req_canceled = crb_req_canceled,
 260         .req_complete_mask = CRB_DRV_STS_COMPLETE,
 261         .req_complete_val = CRB_DRV_STS_COMPLETE,
 262 };
 263
 264 static int crb_check_resource(struct acpi_resource *ares, void *data)
 265 {
 266         struct resource *io_res = data;
 267         struct resource_win win;
 268         struct resource *res = &(win.res);
 269
 270         if (acpi_dev_resource_memory(ares, res) ||
 271             acpi_dev_resource_address_space(ares, &win)) {
 272                 *io_res = *res;
 273                 io_res->name = NULL;
 274         }
 275
 276         return 1;
 277 }
 278
 279 static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
 280                                  struct resource *io_res, u64 start, u32 size)
 281 {
 282         struct resource new_res = {
 283                 .start  = start,
 284                 .end    = start + size - 1,
 285                 .flags  = IORESOURCE_MEM,
 286         };
 287
 288         /* Detect a 64 bit address on a 32 bit system */
 289         if (start != new_res.start)
 290                 return (void __iomem *) ERR_PTR(-EINVAL);
 291
 292         if (!resource_contains(io_res, &new_res))
 293                 return devm_ioremap_resource(dev, &new_res);
 294
 295         return priv->iobase + (new_res.start - io_res->start);
 296 }
 297
 298 static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
 299                       struct acpi_table_tpm2 *buf)
 300 {
 301         struct list_head resources;
 302         struct resource io_res;
 303         struct device *dev = &device->dev;
 304         u32 pa_high, pa_low;
 305         u64 cmd_pa;
 306         u32 cmd_size;
 307         u64 rsp_pa;
 308         u32 rsp_size;
 309         int ret;
 310
 311         INIT_LIST_HEAD(&resources);
 312         ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
 313                                      &io_res);
 314         if (ret < 0)
 315                 return ret;
 316         acpi_dev_free_resource_list(&resources);
 317
 318         if (resource_type(&io_res) != IORESOURCE_MEM) {
 319                 dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
 320                 return -EINVAL;
 321         }
 322
 323         priv->iobase = devm_ioremap_resource(dev, &io_res);
 324         if (IS_ERR(priv->iobase))
 325                 return PTR_ERR(priv->iobase);
 326
 327         priv->cca = crb_map_res(dev, priv, &io_res, buf->control_address,
 328                                 sizeof(struct crb_control_area));
 329         if (IS_ERR(priv->cca))
 330                 return PTR_ERR(priv->cca);
 331
 332         /*
 333          * PTT HW bug w/a: wake up the device to access
 334          * possibly not retained registers.
 335          */
 336         ret = crb_cmd_ready(dev, priv);
 337         if (ret)
 338                 return ret;
 339
 340         pa_high = ioread32(&priv->cca->cmd_pa_high);
 341         pa_low  = ioread32(&priv->cca->cmd_pa_low);
 342         cmd_pa = ((u64)pa_high << 32) | pa_low;
 343         cmd_size = ioread32(&priv->cca->cmd_size);
 344
 345         dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
 346                 pa_high, pa_low, cmd_size);
 347
 348         priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
 349         if (IS_ERR(priv->cmd)) {
 350                 ret = PTR_ERR(priv->cmd);
 351                 goto out;
 352         }
 353
 354         memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8);
 355         rsp_pa = le64_to_cpu(rsp_pa);
 356         rsp_size = ioread32(&priv->cca->rsp_size);
 357
 358         if (cmd_pa != rsp_pa) {
 359                 priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
 360                 ret = PTR_ERR_OR_ZERO(priv->rsp);
 361                 goto out;
 362         }
 363
 364         /* According to the PTP specification, overlapping command and response
 365          * buffer sizes must be identical.
 366          */
 367         if (cmd_size != rsp_size) {
 368                 dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
 369                 ret = -EINVAL;
 370                 goto out;
 371         }
 372
 373         priv->cmd_size = cmd_size;
 374
 375         priv->rsp = priv->cmd;
 376
 377 out:
 378         crb_go_idle(dev, priv);
 379
 380         return ret;
 381 }
 382
 383 static int crb_acpi_add(struct acpi_device *device)
 384 {
 385         struct acpi_table_tpm2 *buf;
 386         struct crb_priv *priv;
 387         struct tpm_chip *chip;
 388         struct device *dev = &device->dev;
 389         acpi_status status;
 390         u32 sm;
 391         int rc;
 392
 393         status = acpi_get_table(ACPI_SIG_TPM2, 1,
 394                                 (struct acpi_table_header **) &buf);
 395         if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
 396                 dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
 397                 return -EINVAL;
 398         }
 399
 400         /* Should the FIFO driver handle this? */
 401         sm = buf->start_method;
 402         if (sm == ACPI_TPM2_MEMORY_MAPPED)
 403                 return -ENODEV;
 404
 405         priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
 406         if (!priv)
 407                 return -ENOMEM;
 408
 409         /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
 410          * report only ACPI start but in practice seems to require both
 411          * ACPI start and CRB start.
 412          */
 413         if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
 414             !strcmp(acpi_device_hid(device), "MSFT0101"))
 415                 priv->flags |= CRB_FL_CRB_START;
 416
 417         if (sm == ACPI_TPM2_START_METHOD ||
 418             sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
 419                 priv->flags |= CRB_FL_ACPI_START;
 420
 421         rc = crb_map_io(device, priv, buf);
 422         if (rc)
 423                 return rc;
 424
 425         chip = tpmm_chip_alloc(dev, &tpm_crb);
 426         if (IS_ERR(chip))
 427                 return PTR_ERR(chip);
 428
 429         dev_set_drvdata(&chip->dev, priv);
 430         chip->acpi_dev_handle = device->handle;
 431         chip->flags = TPM_CHIP_FLAG_TPM2;
 432
 433         rc  = crb_cmd_ready(dev, priv);
 434         if (rc)
 435                 return rc;
 436
 437         pm_runtime_get_noresume(dev);
 438         pm_runtime_set_active(dev);
 439         pm_runtime_enable(dev);
 440
 441         rc = tpm_chip_register(chip);
 442         if (rc) {
 443                 crb_go_idle(dev, priv);
 444                 pm_runtime_put_noidle(dev);
 445                 pm_runtime_disable(dev);
 446                 return rc;
 447         }
 448
 449         pm_runtime_put(dev);
 450
 451         return 0;
 452 }
 453
 454 static int crb_acpi_remove(struct acpi_device *device)
 455 {
 456         struct device *dev = &device->dev;
 457         struct tpm_chip *chip = dev_get_drvdata(dev);
 458
 459         tpm_chip_unregister(chip);
 460
 461         pm_runtime_disable(dev);
 462
 463         return 0;
 464 }
 465
 466 #ifdef CONFIG_PM
 467 static int crb_pm_runtime_suspend(struct device *dev)
 468 {
 469         struct tpm_chip *chip = dev_get_drvdata(dev);
 470         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 471
 472         return crb_go_idle(dev, priv);
 473 }
 474
 475 static int crb_pm_runtime_resume(struct device *dev)
 476 {
 477         struct tpm_chip *chip = dev_get_drvdata(dev);
 478         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 479
 480         return crb_cmd_ready(dev, priv);
 481 }
 482 #endif /* CONFIG_PM */
 483
 484 static const struct dev_pm_ops crb_pm = {
 485         SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
 486         SET_RUNTIME_PM_OPS(crb_pm_runtime_suspend, crb_pm_runtime_resume, NULL)
 487 };
 488
 489 static struct acpi_device_id crb_device_ids[] = {
 490         {"MSFT0101", 0},
 491         {"", 0},
 492 };
 493 MODULE_DEVICE_TABLE(acpi, crb_device_ids);
 494
 495 static struct acpi_driver crb_acpi_driver = {
 496         .name = "tpm_crb",
 497         .ids = crb_device_ids,
 498         .ops = {
 499                 .add = crb_acpi_add,
 500                 .remove = crb_acpi_remove,
 501         },
 502         .drv = {
 503                 .pm = &crb_pm,
 504         },
 505 };
 506
 507 module_acpi_driver(crb_acpi_driver);
 508 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
 509 MODULE_DESCRIPTION("TPM2 Driver");
 510 MODULE_VERSION("0.1");
 511 MODULE_LICENSE("GPL");