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/platform_device.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_start_method {
  38         CRB_SM_ACPI_START = 2,
  39         CRB_SM_CRB = 7,
  40         CRB_SM_CRB_WITH_ACPI_START = 8,
  41 };
  42
  43 struct acpi_tpm2 {
  44         struct acpi_table_header hdr;
  45         u16 platform_class;
  46         u16 reserved;
  47         u64 control_area_pa;
  48         u32 start_method;
  49 } __packed;
  50
  51 enum crb_ca_request {
  52         CRB_CA_REQ_GO_IDLE      = BIT(0),
  53         CRB_CA_REQ_CMD_READY    = BIT(1),
  54 };
  55
  56 enum crb_ca_status {
  57         CRB_CA_STS_ERROR        = BIT(0),
  58         CRB_CA_STS_TPM_IDLE     = BIT(1),
  59 };
  60
  61 enum crb_start {
  62         CRB_START_INVOKE        = BIT(0),
  63 };
  64
  65 enum crb_cancel {
  66         CRB_CANCEL_INVOKE       = BIT(0),
  67 };
  68
  69 struct crb_control_area {
  70         u32 req;
  71         u32 sts;
  72         u32 cancel;
  73         u32 start;
  74         u32 int_enable;
  75         u32 int_sts;
  76         u32 cmd_size;
  77         u64 cmd_pa;
  78         u32 rsp_size;
  79         u64 rsp_pa;
  80 } __packed;
  81
  82 enum crb_status {
  83         CRB_STS_COMPLETE        = BIT(0),
  84 };
  85
  86 enum crb_flags {
  87         CRB_FL_ACPI_START       = BIT(0),
  88         CRB_FL_CRB_START        = BIT(1),
  89 };
  90
  91 struct crb_priv {
  92         unsigned int flags;
  93         struct crb_control_area __iomem *cca;
  94         u8 __iomem *cmd;
  95         u8 __iomem *rsp;
  96 };
  97
  98 static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
  99
 100 static u8 crb_status(struct tpm_chip *chip)
 101 {
 102         struct crb_priv *priv = chip->vendor.priv;
 103         u8 sts = 0;
 104
 105         if ((le32_to_cpu(ioread32(&priv->cca->start)) & CRB_START_INVOKE) !=
 106             CRB_START_INVOKE)
 107                 sts |= CRB_STS_COMPLETE;
 108
 109         return sts;
 110 }
 111
 112 static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 113 {
 114         struct crb_priv *priv = chip->vendor.priv;
 115         unsigned int expected;
 116
 117         /* sanity check */
 118         if (count < 6)
 119                 return -EIO;
 120
 121         if (le32_to_cpu(ioread32(&priv->cca->sts)) & CRB_CA_STS_ERROR)
 122                 return -EIO;
 123
 124         memcpy_fromio(buf, priv->rsp, 6);
 125         expected = be32_to_cpup((__be32 *) &buf[2]);
 126
 127         if (expected > count)
 128                 return -EIO;
 129
 130         memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
 131
 132         return expected;
 133 }
 134
 135 static int crb_do_acpi_start(struct tpm_chip *chip)
 136 {
 137         union acpi_object *obj;
 138         int rc;
 139
 140         obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
 141                                 CRB_ACPI_START_UUID,
 142                                 CRB_ACPI_START_REVISION_ID,
 143                                 CRB_ACPI_START_INDEX,
 144                                 NULL);
 145         if (!obj)
 146                 return -ENXIO;
 147         rc = obj->integer.value == 0 ? 0 : -ENXIO;
 148         ACPI_FREE(obj);
 149         return rc;
 150 }
 151
 152 static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 153 {
 154         struct crb_priv *priv = chip->vendor.priv;
 155         int rc = 0;
 156
 157         if (len > le32_to_cpu(ioread32(&priv->cca->cmd_size))) {
 158                 dev_err(&chip->dev,
 159                         "invalid command count value %x %zx\n",
 160                         (unsigned int) len,
 161                         (size_t) le32_to_cpu(ioread32(&priv->cca->cmd_size)));
 162                 return -E2BIG;
 163         }
 164
 165         memcpy_toio(priv->cmd, buf, len);
 166
 167         /* Make sure that cmd is populated before issuing start. */
 168         wmb();
 169
 170         if (priv->flags & CRB_FL_CRB_START)
 171                 iowrite32(cpu_to_le32(CRB_START_INVOKE), &priv->cca->start);
 172
 173         if (priv->flags & CRB_FL_ACPI_START)
 174                 rc = crb_do_acpi_start(chip);
 175
 176         return rc;
 177 }
 178
 179 static void crb_cancel(struct tpm_chip *chip)
 180 {
 181         struct crb_priv *priv = chip->vendor.priv;
 182
 183         iowrite32(cpu_to_le32(CRB_CANCEL_INVOKE), &priv->cca->cancel);
 184
 185         /* Make sure that cmd is populated before issuing cancel. */
 186         wmb();
 187
 188         if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip))
 189                 dev_err(&chip->dev, "ACPI Start failed\n");
 190
 191         iowrite32(0, &priv->cca->cancel);
 192 }
 193
 194 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
 195 {
 196         struct crb_priv *priv = chip->vendor.priv;
 197         u32 cancel = le32_to_cpu(ioread32(&priv->cca->cancel));
 198
 199         return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
 200 }
 201
 202 static const struct tpm_class_ops tpm_crb = {
 203         .status = crb_status,
 204         .recv = crb_recv,
 205         .send = crb_send,
 206         .cancel = crb_cancel,
 207         .req_canceled = crb_req_canceled,
 208         .req_complete_mask = CRB_STS_COMPLETE,
 209         .req_complete_val = CRB_STS_COMPLETE,
 210 };
 211
 212 static int crb_acpi_add(struct acpi_device *device)
 213 {
 214         struct tpm_chip *chip;
 215         struct acpi_tpm2 *buf;
 216         struct crb_priv *priv;
 217         struct device *dev = &device->dev;
 218         acpi_status status;
 219         u32 sm;
 220         u64 pa;
 221         int rc;
 222
 223         chip = tpmm_chip_alloc(dev, &tpm_crb);
 224         if (IS_ERR(chip))
 225                 return PTR_ERR(chip);
 226
 227         chip->flags = TPM_CHIP_FLAG_TPM2;
 228
 229         status = acpi_get_table(ACPI_SIG_TPM2, 1,
 230                                 (struct acpi_table_header **) &buf);
 231         if (ACPI_FAILURE(status)) {
 232                 dev_err(dev, "failed to get TPM2 ACPI table\n");
 233                 return -ENODEV;
 234         }
 235
 236         if (buf->hdr.length < sizeof(struct acpi_tpm2)) {
 237                 dev_err(dev, "TPM2 ACPI table has wrong size");
 238                 return -EINVAL;
 239         }
 240
 241         priv = (struct crb_priv *) devm_kzalloc(dev, sizeof(struct crb_priv),
 242                                                 GFP_KERNEL);
 243         if (!priv) {
 244                 dev_err(dev, "failed to devm_kzalloc for private data\n");
 245                 return -ENOMEM;
 246         }
 247
 248         sm = le32_to_cpu(buf->start_method);
 249
 250         /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
 251          * report only ACPI start but in practice seems to require both
 252          * ACPI start and CRB start.
 253          */
 254         if (sm == CRB_SM_CRB || sm == CRB_SM_CRB_WITH_ACPI_START ||
 255             !strcmp(acpi_device_hid(device), "MSFT0101"))
 256                 priv->flags |= CRB_FL_CRB_START;
 257
 258         if (sm == CRB_SM_ACPI_START || sm == CRB_SM_CRB_WITH_ACPI_START)
 259                 priv->flags |= CRB_FL_ACPI_START;
 260
 261         priv->cca = (struct crb_control_area __iomem *)
 262                 devm_ioremap_nocache(dev, buf->control_area_pa, 0x1000);
 263         if (!priv->cca) {
 264                 dev_err(dev, "ioremap of the control area failed\n");
 265                 return -ENOMEM;
 266         }
 267
 268         memcpy_fromio(&pa, &priv->cca->cmd_pa, 8);
 269         pa = le64_to_cpu(pa);
 270         priv->cmd = devm_ioremap_nocache(dev, le64_to_cpu(pa),
 271                                          ioread32(&priv->cca->cmd_size));
 272         if (!priv->cmd) {
 273                 dev_err(dev, "ioremap of the command buffer failed\n");
 274                 return -ENOMEM;
 275         }
 276
 277         memcpy_fromio(&pa, &priv->cca->rsp_pa, 8);
 278         pa = le64_to_cpu(pa);
 279         priv->rsp = devm_ioremap_nocache(dev, le64_to_cpu(pa),
 280                                          ioread32(&priv->cca->rsp_size));
 281         if (!priv->rsp) {
 282                 dev_err(dev, "ioremap of the response buffer failed\n");
 283                 return -ENOMEM;
 284         }
 285
 286         chip->vendor.priv = priv;
 287
 288         /* Default timeouts and durations */
 289         chip->vendor.timeout_a = msecs_to_jiffies(TPM2_TIMEOUT_A);
 290         chip->vendor.timeout_b = msecs_to_jiffies(TPM2_TIMEOUT_B);
 291         chip->vendor.timeout_c = msecs_to_jiffies(TPM2_TIMEOUT_C);
 292         chip->vendor.timeout_d = msecs_to_jiffies(TPM2_TIMEOUT_D);
 293         chip->vendor.duration[TPM_SHORT] =
 294                 msecs_to_jiffies(TPM2_DURATION_SHORT);
 295         chip->vendor.duration[TPM_MEDIUM] =
 296                 msecs_to_jiffies(TPM2_DURATION_MEDIUM);
 297         chip->vendor.duration[TPM_LONG] =
 298                 msecs_to_jiffies(TPM2_DURATION_LONG);
 299
 300         chip->acpi_dev_handle = device->handle;
 301
 302         rc = tpm2_do_selftest(chip);
 303         if (rc)
 304                 return rc;
 305
 306         return tpm_chip_register(chip);
 307 }
 308
 309 static int crb_acpi_remove(struct acpi_device *device)
 310 {
 311         struct device *dev = &device->dev;
 312         struct tpm_chip *chip = dev_get_drvdata(dev);
 313
 314         tpm_chip_unregister(chip);
 315
 316         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 317                 tpm2_shutdown(chip, TPM2_SU_CLEAR);
 318
 319         return 0;
 320 }
 321
 322 static struct acpi_device_id crb_device_ids[] = {
 323         {"MSFT0101", 0},
 324         {"", 0},
 325 };
 326 MODULE_DEVICE_TABLE(acpi, crb_device_ids);
 327
 328 static struct acpi_driver crb_acpi_driver = {
 329         .name = "tpm_crb",
 330         .ids = crb_device_ids,
 331         .ops = {
 332                 .add = crb_acpi_add,
 333                 .remove = crb_acpi_remove,
 334         },
 335         .drv = {
 336                 .pm = &crb_pm,
 337         },
 338 };
 339
 340 module_acpi_driver(crb_acpi_driver);
 341 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
 342 MODULE_DESCRIPTION("TPM2 Driver");
 343 MODULE_VERSION("0.1");
 344 MODULE_LICENSE("GPL");