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 res;
 268
 269         if (acpi_dev_resource_memory(ares, &res)) {
 270                 *io_res = res;
 271                 io_res->name = NULL;
 272         }
 273
 274         return 1;
 275 }
 276
 277 static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
 278                                  struct resource *io_res, u64 start, u32 size)
 279 {
 280         struct resource new_res = {
 281                 .start  = start,
 282                 .end    = start + size - 1,
 283                 .flags  = IORESOURCE_MEM,
 284         };
 285
 286         /* Detect a 64 bit address on a 32 bit system */
 287         if (start != new_res.start)
 288                 return (void __iomem *) ERR_PTR(-EINVAL);
 289
 290         if (!resource_contains(io_res, &new_res))
 291                 return devm_ioremap_resource(dev, &new_res);
 292
 293         return priv->iobase + (new_res.start - io_res->start);
 294 }
 295
 296 static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
 297                       struct acpi_table_tpm2 *buf)
 298 {
 299         struct list_head resources;
 300         struct resource io_res;
 301         struct device *dev = &device->dev;
 302         u32 pa_high, pa_low;
 303         u64 cmd_pa;
 304         u32 cmd_size;
 305         u64 rsp_pa;
 306         u32 rsp_size;
 307         int ret;
 308
 309         INIT_LIST_HEAD(&resources);
 310         ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
 311                                      &io_res);
 312         if (ret < 0)
 313                 return ret;
 314         acpi_dev_free_resource_list(&resources);
 315
 316         if (resource_type(&io_res) != IORESOURCE_MEM) {
 317                 dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
 318                 return -EINVAL;
 319         }
 320
 321         priv->iobase = devm_ioremap_resource(dev, &io_res);
 322         if (IS_ERR(priv->iobase))
 323                 return PTR_ERR(priv->iobase);
 324
 325         priv->cca = crb_map_res(dev, priv, &io_res, buf->control_address,
 326                                 sizeof(struct crb_control_area));
 327         if (IS_ERR(priv->cca))
 328                 return PTR_ERR(priv->cca);
 329
 330         /*
 331          * PTT HW bug w/a: wake up the device to access
 332          * possibly not retained registers.
 333          */
 334         ret = crb_cmd_ready(dev, priv);
 335         if (ret)
 336                 return ret;
 337
 338         pa_high = ioread32(&priv->cca->cmd_pa_high);
 339         pa_low  = ioread32(&priv->cca->cmd_pa_low);
 340         cmd_pa = ((u64)pa_high << 32) | pa_low;
 341         cmd_size = ioread32(&priv->cca->cmd_size);
 342
 343         dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n",
 344                 pa_high, pa_low, cmd_size);
 345
 346         priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
 347         if (IS_ERR(priv->cmd)) {
 348                 ret = PTR_ERR(priv->cmd);
 349                 goto out;
 350         }
 351
 352         memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8);
 353         rsp_pa = le64_to_cpu(rsp_pa);
 354         rsp_size = ioread32(&priv->cca->rsp_size);
 355
 356         if (cmd_pa != rsp_pa) {
 357                 priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
 358                 ret = PTR_ERR_OR_ZERO(priv->rsp);
 359                 goto out;
 360         }
 361
 362         /* According to the PTP specification, overlapping command and response
 363          * buffer sizes must be identical.
 364          */
 365         if (cmd_size != rsp_size) {
 366                 dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
 367                 ret = -EINVAL;
 368                 goto out;
 369         }
 370
 371         priv->cmd_size = cmd_size;
 372
 373         priv->rsp = priv->cmd;
 374
 375 out:
 376         crb_go_idle(dev, priv);
 377
 378         return ret;
 379 }
 380
 381 static int crb_acpi_add(struct acpi_device *device)
 382 {
 383         struct acpi_table_tpm2 *buf;
 384         struct crb_priv *priv;
 385         struct tpm_chip *chip;
 386         struct device *dev = &device->dev;
 387         acpi_status status;
 388         u32 sm;
 389         int rc;
 390
 391         status = acpi_get_table(ACPI_SIG_TPM2, 1,
 392                                 (struct acpi_table_header **) &buf);
 393         if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
 394                 dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
 395                 return -EINVAL;
 396         }
 397
 398         /* Should the FIFO driver handle this? */
 399         sm = buf->start_method;
 400         if (sm == ACPI_TPM2_MEMORY_MAPPED)
 401                 return -ENODEV;
 402
 403         priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
 404         if (!priv)
 405                 return -ENOMEM;
 406
 407         /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
 408          * report only ACPI start but in practice seems to require both
 409          * ACPI start and CRB start.
 410          */
 411         if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
 412             !strcmp(acpi_device_hid(device), "MSFT0101"))
 413                 priv->flags |= CRB_FL_CRB_START;
 414
 415         if (sm == ACPI_TPM2_START_METHOD ||
 416             sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
 417                 priv->flags |= CRB_FL_ACPI_START;
 418
 419         rc = crb_map_io(device, priv, buf);
 420         if (rc)
 421                 return rc;
 422
 423         chip = tpmm_chip_alloc(dev, &tpm_crb);
 424         if (IS_ERR(chip))
 425                 return PTR_ERR(chip);
 426
 427         dev_set_drvdata(&chip->dev, priv);
 428         chip->acpi_dev_handle = device->handle;
 429         chip->flags = TPM_CHIP_FLAG_TPM2;
 430
 431         rc  = crb_cmd_ready(dev, priv);
 432         if (rc)
 433                 return rc;
 434
 435         pm_runtime_get_noresume(dev);
 436         pm_runtime_set_active(dev);
 437         pm_runtime_enable(dev);
 438
 439         rc = tpm_chip_register(chip);
 440         if (rc) {
 441                 crb_go_idle(dev, priv);
 442                 pm_runtime_put_noidle(dev);
 443                 pm_runtime_disable(dev);
 444                 return rc;
 445         }
 446
 447         pm_runtime_put(dev);
 448
 449         return 0;
 450 }
 451
 452 static int crb_acpi_remove(struct acpi_device *device)
 453 {
 454         struct device *dev = &device->dev;
 455         struct tpm_chip *chip = dev_get_drvdata(dev);
 456
 457         tpm_chip_unregister(chip);
 458
 459         pm_runtime_disable(dev);
 460
 461         return 0;
 462 }
 463
 464 #ifdef CONFIG_PM
 465 static int crb_pm_runtime_suspend(struct device *dev)
 466 {
 467         struct tpm_chip *chip = dev_get_drvdata(dev);
 468         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 469
 470         return crb_go_idle(dev, priv);
 471 }
 472
 473 static int crb_pm_runtime_resume(struct device *dev)
 474 {
 475         struct tpm_chip *chip = dev_get_drvdata(dev);
 476         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 477
 478         return crb_cmd_ready(dev, priv);
 479 }
 480 #endif /* CONFIG_PM */
 481
 482 static const struct dev_pm_ops crb_pm = {
 483         SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
 484         SET_RUNTIME_PM_OPS(crb_pm_runtime_suspend, crb_pm_runtime_resume, NULL)
 485 };
 486
 487 static struct acpi_device_id crb_device_ids[] = {
 488         {"MSFT0101", 0},
 489         {"", 0},
 490 };
 491 MODULE_DEVICE_TABLE(acpi, crb_device_ids);
 492
 493 static struct acpi_driver crb_acpi_driver = {
 494         .name = "tpm_crb",
 495         .ids = crb_device_ids,
 496         .ops = {
 497                 .add = crb_acpi_add,
 498                 .remove = crb_acpi_remove,
 499         },
 500         .drv = {
 501                 .pm = &crb_pm,
 502         },
 503 };
 504
 505 module_acpi_driver(crb_acpi_driver);
 506 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
 507 MODULE_DESCRIPTION("TPM2 Driver");
 508 MODULE_VERSION("0.1");
 509 MODULE_LICENSE("GPL");