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_ca_request {
  38         CRB_CA_REQ_GO_IDLE      = BIT(0),
  39         CRB_CA_REQ_CMD_READY    = BIT(1),
  40 };
  41
  42 enum crb_ca_status {
  43         CRB_CA_STS_ERROR        = BIT(0),
  44         CRB_CA_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_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         struct crb_control_area __iomem *cca;
  81         u8 __iomem *cmd;
  82         u8 __iomem *rsp;
  83 };
  84
  85 static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
  86
  87 static u8 crb_status(struct tpm_chip *chip)
  88 {
  89         struct crb_priv *priv = chip->vendor.priv;
  90         u8 sts = 0;
  91
  92         if ((le32_to_cpu(ioread32(&priv->cca->start)) & CRB_START_INVOKE) !=
  93             CRB_START_INVOKE)
  94                 sts |= CRB_STS_COMPLETE;
  95
  96         return sts;
  97 }
  98
  99 static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 100 {
 101         struct crb_priv *priv = chip->vendor.priv;
 102         unsigned int expected;
 103
 104         /* sanity check */
 105         if (count < 6)
 106                 return -EIO;
 107
 108         if (le32_to_cpu(ioread32(&priv->cca->sts)) & CRB_CA_STS_ERROR)
 109                 return -EIO;
 110
 111         memcpy_fromio(buf, priv->rsp, 6);
 112         expected = be32_to_cpup((__be32 *) &buf[2]);
 113
 114         if (expected > count)
 115                 return -EIO;
 116
 117         memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
 118
 119         return expected;
 120 }
 121
 122 static int crb_do_acpi_start(struct tpm_chip *chip)
 123 {
 124         union acpi_object *obj;
 125         int rc;
 126
 127         obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
 128                                 CRB_ACPI_START_UUID,
 129                                 CRB_ACPI_START_REVISION_ID,
 130                                 CRB_ACPI_START_INDEX,
 131                                 NULL);
 132         if (!obj)
 133                 return -ENXIO;
 134         rc = obj->integer.value == 0 ? 0 : -ENXIO;
 135         ACPI_FREE(obj);
 136         return rc;
 137 }
 138
 139 static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 140 {
 141         struct crb_priv *priv = chip->vendor.priv;
 142         int rc = 0;
 143
 144         if (len > le32_to_cpu(ioread32(&priv->cca->cmd_size))) {
 145                 dev_err(&chip->dev,
 146                         "invalid command count value %x %zx\n",
 147                         (unsigned int) len,
 148                         (size_t) le32_to_cpu(ioread32(&priv->cca->cmd_size)));
 149                 return -E2BIG;
 150         }
 151
 152         memcpy_toio(priv->cmd, buf, len);
 153
 154         /* Make sure that cmd is populated before issuing start. */
 155         wmb();
 156
 157         if (priv->flags & CRB_FL_CRB_START)
 158                 iowrite32(cpu_to_le32(CRB_START_INVOKE), &priv->cca->start);
 159
 160         if (priv->flags & CRB_FL_ACPI_START)
 161                 rc = crb_do_acpi_start(chip);
 162
 163         return rc;
 164 }
 165
 166 static void crb_cancel(struct tpm_chip *chip)
 167 {
 168         struct crb_priv *priv = chip->vendor.priv;
 169
 170         iowrite32(cpu_to_le32(CRB_CANCEL_INVOKE), &priv->cca->cancel);
 171
 172         /* Make sure that cmd is populated before issuing cancel. */
 173         wmb();
 174
 175         if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip))
 176                 dev_err(&chip->dev, "ACPI Start failed\n");
 177
 178         iowrite32(0, &priv->cca->cancel);
 179 }
 180
 181 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
 182 {
 183         struct crb_priv *priv = chip->vendor.priv;
 184         u32 cancel = le32_to_cpu(ioread32(&priv->cca->cancel));
 185
 186         return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
 187 }
 188
 189 static const struct tpm_class_ops tpm_crb = {
 190         .status = crb_status,
 191         .recv = crb_recv,
 192         .send = crb_send,
 193         .cancel = crb_cancel,
 194         .req_canceled = crb_req_canceled,
 195         .req_complete_mask = CRB_STS_COMPLETE,
 196         .req_complete_val = CRB_STS_COMPLETE,
 197 };
 198
 199 static int crb_acpi_add(struct acpi_device *device)
 200 {
 201         struct tpm_chip *chip;
 202         struct acpi_table_tpm2 *buf;
 203         struct crb_priv *priv;
 204         struct device *dev = &device->dev;
 205         acpi_status status;
 206         u32 sm;
 207         u64 pa;
 208         int rc;
 209
 210         status = acpi_get_table(ACPI_SIG_TPM2, 1,
 211                                 (struct acpi_table_header **) &buf);
 212         if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
 213                 dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
 214                 return -ENODEV;
 215         }
 216
 217         /* Should the FIFO driver handle this? */
 218         sm = buf->start_method;
 219         if (sm == ACPI_TPM2_MEMORY_MAPPED)
 220                 return -ENODEV;
 221
 222         chip = tpmm_chip_alloc(dev, &tpm_crb);
 223         if (IS_ERR(chip))
 224                 return PTR_ERR(chip);
 225
 226         chip->flags = TPM_CHIP_FLAG_TPM2;
 227
 228         priv = (struct crb_priv *) devm_kzalloc(dev, sizeof(struct crb_priv),
 229                                                 GFP_KERNEL);
 230         if (!priv) {
 231                 dev_err(dev, "failed to devm_kzalloc for private data\n");
 232                 return -ENOMEM;
 233         }
 234
 235         /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
 236          * report only ACPI start but in practice seems to require both
 237          * ACPI start and CRB start.
 238          */
 239         if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
 240             !strcmp(acpi_device_hid(device), "MSFT0101"))
 241                 priv->flags |= CRB_FL_CRB_START;
 242
 243         if (sm == ACPI_TPM2_START_METHOD ||
 244             sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
 245                 priv->flags |= CRB_FL_ACPI_START;
 246
 247         priv->cca = (struct crb_control_area __iomem *)
 248                 devm_ioremap_nocache(dev, buf->control_address, 0x1000);
 249         if (!priv->cca) {
 250                 dev_err(dev, "ioremap of the control area failed\n");
 251                 return -ENOMEM;
 252         }
 253
 254         pa = ((u64) le32_to_cpu(ioread32(&priv->cca->cmd_pa_high)) << 32) |
 255                 (u64) le32_to_cpu(ioread32(&priv->cca->cmd_pa_low));
 256         priv->cmd = devm_ioremap_nocache(dev, pa,
 257                                          ioread32(&priv->cca->cmd_size));
 258         if (!priv->cmd) {
 259                 dev_err(dev, "ioremap of the command buffer failed\n");
 260                 return -ENOMEM;
 261         }
 262
 263         memcpy_fromio(&pa, &priv->cca->rsp_pa, 8);
 264         pa = le64_to_cpu(pa);
 265         priv->rsp = devm_ioremap_nocache(dev, pa,
 266                                          ioread32(&priv->cca->rsp_size));
 267         if (!priv->rsp) {
 268                 dev_err(dev, "ioremap of the response buffer failed\n");
 269                 return -ENOMEM;
 270         }
 271
 272         chip->vendor.priv = priv;
 273
 274         rc = tpm_get_timeouts(chip);
 275         if (rc)
 276                 return rc;
 277
 278         chip->acpi_dev_handle = device->handle;
 279
 280         rc = tpm2_do_selftest(chip);
 281         if (rc)
 282                 return rc;
 283
 284         return tpm_chip_register(chip);
 285 }
 286
 287 static int crb_acpi_remove(struct acpi_device *device)
 288 {
 289         struct device *dev = &device->dev;
 290         struct tpm_chip *chip = dev_get_drvdata(dev);
 291
 292         tpm_chip_unregister(chip);
 293
 294         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 295                 tpm2_shutdown(chip, TPM2_SU_CLEAR);
 296
 297         return 0;
 298 }
 299
 300 static struct acpi_device_id crb_device_ids[] = {
 301         {"MSFT0101", 0},
 302         {"", 0},
 303 };
 304 MODULE_DEVICE_TABLE(acpi, crb_device_ids);
 305
 306 static struct acpi_driver crb_acpi_driver = {
 307         .name = "tpm_crb",
 308         .ids = crb_device_ids,
 309         .ops = {
 310                 .add = crb_acpi_add,
 311                 .remove = crb_acpi_remove,
 312         },
 313         .drv = {
 314                 .pm = &crb_pm,
 315         },
 316 };
 317
 318 module_acpi_driver(crb_acpi_driver);
 319 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
 320 MODULE_DESCRIPTION("TPM2 Driver");
 321 MODULE_VERSION("0.1");
 322 MODULE_LICENSE("GPL");