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 struct acpi_tpm2 {
  38         struct acpi_table_header hdr;
  39         u16 platform_class;
  40         u16 reserved;
  41         u64 control_area_pa;
  42         u32 start_method;
  43 } __packed;
  44
  45 enum crb_ca_request {
  46         CRB_CA_REQ_GO_IDLE      = BIT(0),
  47         CRB_CA_REQ_CMD_READY    = BIT(1),
  48 };
  49
  50 enum crb_ca_status {
  51         CRB_CA_STS_ERROR        = BIT(0),
  52         CRB_CA_STS_TPM_IDLE     = BIT(1),
  53 };
  54
  55 enum crb_start {
  56         CRB_START_INVOKE        = BIT(0),
  57 };
  58
  59 enum crb_cancel {
  60         CRB_CANCEL_INVOKE       = BIT(0),
  61 };
  62
  63 struct crb_control_area {
  64         u32 req;
  65         u32 sts;
  66         u32 cancel;
  67         u32 start;
  68         u32 int_enable;
  69         u32 int_sts;
  70         u32 cmd_size;
  71         u32 cmd_pa_low;
  72         u32 cmd_pa_high;
  73         u32 rsp_size;
  74         u64 rsp_pa;
  75 } __packed;
  76
  77 enum crb_status {
  78         CRB_STS_COMPLETE        = BIT(0),
  79 };
  80
  81 enum crb_flags {
  82         CRB_FL_ACPI_START       = BIT(0),
  83         CRB_FL_CRB_START        = BIT(1),
  84 };
  85
  86 struct crb_priv {
  87         unsigned int flags;
  88         struct crb_control_area __iomem *cca;
  89         u8 __iomem *cmd;
  90         u8 __iomem *rsp;
  91 };
  92
  93 static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
  94
  95 static u8 crb_status(struct tpm_chip *chip)
  96 {
  97         struct crb_priv *priv = chip->vendor.priv;
  98         u8 sts = 0;
  99
 100         if ((le32_to_cpu(ioread32(&priv->cca->start)) & CRB_START_INVOKE) !=
 101             CRB_START_INVOKE)
 102                 sts |= CRB_STS_COMPLETE;
 103
 104         return sts;
 105 }
 106
 107 static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 108 {
 109         struct crb_priv *priv = chip->vendor.priv;
 110         unsigned int expected;
 111
 112         /* sanity check */
 113         if (count < 6)
 114                 return -EIO;
 115
 116         if (le32_to_cpu(ioread32(&priv->cca->sts)) & CRB_CA_STS_ERROR)
 117                 return -EIO;
 118
 119         memcpy_fromio(buf, priv->rsp, 6);
 120         expected = be32_to_cpup((__be32 *) &buf[2]);
 121
 122         if (expected > count)
 123                 return -EIO;
 124
 125         memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
 126
 127         return expected;
 128 }
 129
 130 static int crb_do_acpi_start(struct tpm_chip *chip)
 131 {
 132         union acpi_object *obj;
 133         int rc;
 134
 135         obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
 136                                 CRB_ACPI_START_UUID,
 137                                 CRB_ACPI_START_REVISION_ID,
 138                                 CRB_ACPI_START_INDEX,
 139                                 NULL);
 140         if (!obj)
 141                 return -ENXIO;
 142         rc = obj->integer.value == 0 ? 0 : -ENXIO;
 143         ACPI_FREE(obj);
 144         return rc;
 145 }
 146
 147 static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 148 {
 149         struct crb_priv *priv = chip->vendor.priv;
 150         int rc = 0;
 151
 152         if (len > le32_to_cpu(ioread32(&priv->cca->cmd_size))) {
 153                 dev_err(&chip->dev,
 154                         "invalid command count value %x %zx\n",
 155                         (unsigned int) len,
 156                         (size_t) le32_to_cpu(ioread32(&priv->cca->cmd_size)));
 157                 return -E2BIG;
 158         }
 159
 160         memcpy_toio(priv->cmd, buf, len);
 161
 162         /* Make sure that cmd is populated before issuing start. */
 163         wmb();
 164
 165         if (priv->flags & CRB_FL_CRB_START)
 166                 iowrite32(cpu_to_le32(CRB_START_INVOKE), &priv->cca->start);
 167
 168         if (priv->flags & CRB_FL_ACPI_START)
 169                 rc = crb_do_acpi_start(chip);
 170
 171         return rc;
 172 }
 173
 174 static void crb_cancel(struct tpm_chip *chip)
 175 {
 176         struct crb_priv *priv = chip->vendor.priv;
 177
 178         iowrite32(cpu_to_le32(CRB_CANCEL_INVOKE), &priv->cca->cancel);
 179
 180         /* Make sure that cmd is populated before issuing cancel. */
 181         wmb();
 182
 183         if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip))
 184                 dev_err(&chip->dev, "ACPI Start failed\n");
 185
 186         iowrite32(0, &priv->cca->cancel);
 187 }
 188
 189 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
 190 {
 191         struct crb_priv *priv = chip->vendor.priv;
 192         u32 cancel = le32_to_cpu(ioread32(&priv->cca->cancel));
 193
 194         return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
 195 }
 196
 197 static const struct tpm_class_ops tpm_crb = {
 198         .status = crb_status,
 199         .recv = crb_recv,
 200         .send = crb_send,
 201         .cancel = crb_cancel,
 202         .req_canceled = crb_req_canceled,
 203         .req_complete_mask = CRB_STS_COMPLETE,
 204         .req_complete_val = CRB_STS_COMPLETE,
 205 };
 206
 207 static int crb_acpi_add(struct acpi_device *device)
 208 {
 209         struct tpm_chip *chip;
 210         struct acpi_tpm2 *buf;
 211         struct crb_priv *priv;
 212         struct device *dev = &device->dev;
 213         acpi_status status;
 214         u32 sm;
 215         u64 pa;
 216         int rc;
 217
 218         status = acpi_get_table(ACPI_SIG_TPM2, 1,
 219                                 (struct acpi_table_header **) &buf);
 220         if (ACPI_FAILURE(status)) {
 221                 dev_err(dev, "failed to get TPM2 ACPI table\n");
 222                 return -ENODEV;
 223         }
 224
 225         /* Should the FIFO driver handle this? */
 226         if (buf->start_method == TPM2_START_FIFO)
 227                 return -ENODEV;
 228
 229         chip = tpmm_chip_alloc(dev, &tpm_crb);
 230         if (IS_ERR(chip))
 231                 return PTR_ERR(chip);
 232
 233         chip->flags = TPM_CHIP_FLAG_TPM2;
 234
 235         if (buf->hdr.length < sizeof(struct acpi_tpm2)) {
 236                 dev_err(dev, "TPM2 ACPI table has wrong size");
 237                 return -EINVAL;
 238         }
 239
 240         priv = (struct crb_priv *) devm_kzalloc(dev, sizeof(struct crb_priv),
 241                                                 GFP_KERNEL);
 242         if (!priv) {
 243                 dev_err(dev, "failed to devm_kzalloc for private data\n");
 244                 return -ENOMEM;
 245         }
 246
 247         sm = le32_to_cpu(buf->start_method);
 248
 249         /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
 250          * report only ACPI start but in practice seems to require both
 251          * ACPI start and CRB start.
 252          */
 253         if (sm == TPM2_START_CRB || sm == TPM2_START_FIFO ||
 254             !strcmp(acpi_device_hid(device), "MSFT0101"))
 255                 priv->flags |= CRB_FL_CRB_START;
 256
 257         if (sm == TPM2_START_ACPI || sm == TPM2_START_CRB_WITH_ACPI)
 258                 priv->flags |= CRB_FL_ACPI_START;
 259
 260         priv->cca = (struct crb_control_area __iomem *)
 261                 devm_ioremap_nocache(dev, buf->control_area_pa, 0x1000);
 262         if (!priv->cca) {
 263                 dev_err(dev, "ioremap of the control area failed\n");
 264                 return -ENOMEM;
 265         }
 266
 267         pa = ((u64) le32_to_cpu(ioread32(&priv->cca->cmd_pa_high)) << 32) |
 268                 (u64) le32_to_cpu(ioread32(&priv->cca->cmd_pa_low));
 269         priv->cmd = devm_ioremap_nocache(dev, pa,
 270                                          ioread32(&priv->cca->cmd_size));
 271         if (!priv->cmd) {
 272                 dev_err(dev, "ioremap of the command buffer failed\n");
 273                 return -ENOMEM;
 274         }
 275
 276         memcpy_fromio(&pa, &priv->cca->rsp_pa, 8);
 277         pa = le64_to_cpu(pa);
 278         priv->rsp = devm_ioremap_nocache(dev, pa,
 279                                          ioread32(&priv->cca->rsp_size));
 280         if (!priv->rsp) {
 281                 dev_err(dev, "ioremap of the response buffer failed\n");
 282                 return -ENOMEM;
 283         }
 284
 285         chip->vendor.priv = priv;
 286
 287         rc = tpm_get_timeouts(chip);
 288         if (rc)
 289                 return rc;
 290
 291         chip->acpi_dev_handle = device->handle;
 292
 293         rc = tpm2_do_selftest(chip);
 294         if (rc)
 295                 return rc;
 296
 297         return tpm_chip_register(chip);
 298 }
 299
 300 static int crb_acpi_remove(struct acpi_device *device)
 301 {
 302         struct device *dev = &device->dev;
 303         struct tpm_chip *chip = dev_get_drvdata(dev);
 304
 305         tpm_chip_unregister(chip);
 306
 307         if (chip->flags & TPM_CHIP_FLAG_TPM2)
 308                 tpm2_shutdown(chip, TPM2_SU_CLEAR);
 309
 310         return 0;
 311 }
 312
 313 static struct acpi_device_id crb_device_ids[] = {
 314         {"MSFT0101", 0},
 315         {"", 0},
 316 };
 317 MODULE_DEVICE_TABLE(acpi, crb_device_ids);
 318
 319 static struct acpi_driver crb_acpi_driver = {
 320         .name = "tpm_crb",
 321         .ids = crb_device_ids,
 322         .ops = {
 323                 .add = crb_acpi_add,
 324                 .remove = crb_acpi_remove,
 325         },
 326         .drv = {
 327                 .pm = &crb_pm,
 328         },
 329 };
 330
 331 module_acpi_driver(crb_acpi_driver);
 332 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
 333 MODULE_DESCRIPTION("TPM2 Driver");
 334 MODULE_VERSION("0.1");
 335 MODULE_LICENSE("GPL");