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 "tpm.h"
  23
  24 #define ACPI_SIG_TPM2 "TPM2"
  25
  26 static const u8 CRB_ACPI_START_UUID[] = {
  27         /* 0000 */ 0xAB, 0x6C, 0xBF, 0x6B, 0x63, 0x54, 0x14, 0x47,
  28         /* 0008 */ 0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4
  29 };
  30
  31 enum crb_defaults {
  32         CRB_ACPI_START_REVISION_ID = 1,
  33         CRB_ACPI_START_INDEX = 1,
  34 };
  35
  36 enum crb_ctrl_req {
  37         CRB_CTRL_REQ_CMD_READY  = BIT(0),
  38         CRB_CTRL_REQ_GO_IDLE    = BIT(1),
  39 };
  40
  41 enum crb_ctrl_sts {
  42         CRB_CTRL_STS_ERROR      = BIT(0),
  43         CRB_CTRL_STS_TPM_IDLE   = BIT(1),
  44 };
  45
  46 enum crb_start {
  47         CRB_START_INVOKE        = BIT(0),
  48 };
  49
  50 enum crb_cancel {
  51         CRB_CANCEL_INVOKE       = BIT(0),
  52 };
  53
  54 struct crb_control_area {
  55         u32 req;
  56         u32 sts;
  57         u32 cancel;
  58         u32 start;
  59         u32 int_enable;
  60         u32 int_sts;
  61         u32 cmd_size;
  62         u32 cmd_pa_low;
  63         u32 cmd_pa_high;
  64         u32 rsp_size;
  65         u64 rsp_pa;
  66 } __packed;
  67
  68 enum crb_status {
  69         CRB_DRV_STS_COMPLETE    = BIT(0),
  70 };
  71
  72 enum crb_flags {
  73         CRB_FL_ACPI_START       = BIT(0),
  74         CRB_FL_CRB_START        = BIT(1),
  75 };
  76
  77 struct crb_priv {
  78         unsigned int flags;
  79         void __iomem *iobase;
  80         struct crb_control_area __iomem *cca;
  81         u8 __iomem *cmd;
  82         u8 __iomem *rsp;
  83         u32 cmd_size;
  84 };
  85
  86 static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
  87
  88 static u8 crb_status(struct tpm_chip *chip)
  89 {
  90         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
  91         u8 sts = 0;
  92
  93         if ((ioread32(&priv->cca->start) & CRB_START_INVOKE) !=
  94             CRB_START_INVOKE)
  95                 sts |= CRB_DRV_STS_COMPLETE;
  96
  97         return sts;
  98 }
  99
 100 static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
 101 {
 102         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 103         unsigned int expected;
 104
 105         /* sanity check */
 106         if (count < 6)
 107                 return -EIO;
 108
 109         if (ioread32(&priv->cca->sts) & CRB_CTRL_STS_ERROR)
 110                 return -EIO;
 111
 112         memcpy_fromio(buf, priv->rsp, 6);
 113         expected = be32_to_cpup((__be32 *) &buf[2]);
 114
 115         if (expected > count)
 116                 return -EIO;
 117
 118         memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
 119
 120         return expected;
 121 }
 122
 123 static int crb_do_acpi_start(struct tpm_chip *chip)
 124 {
 125         union acpi_object *obj;
 126         int rc;
 127
 128         obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
 129                                 CRB_ACPI_START_UUID,
 130                                 CRB_ACPI_START_REVISION_ID,
 131                                 CRB_ACPI_START_INDEX,
 132                                 NULL);
 133         if (!obj)
 134                 return -ENXIO;
 135         rc = obj->integer.value == 0 ? 0 : -ENXIO;
 136         ACPI_FREE(obj);
 137         return rc;
 138 }
 139
 140 static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
 141 {
 142         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 143         int rc = 0;
 144
 145         /* Zero the cancel register so that the next command will not get
 146          * canceled.
 147          */
 148         iowrite32(0, &priv->cca->cancel);
 149
 150         if (len > priv->cmd_size) {
 151                 dev_err(&chip->dev, "invalid command count value %zd %d\n",
 152                         len, priv->cmd_size);
 153                 return -E2BIG;
 154         }
 155
 156         memcpy_toio(priv->cmd, buf, len);
 157
 158         /* Make sure that cmd is populated before issuing start. */
 159         wmb();
 160
 161         if (priv->flags & CRB_FL_CRB_START)
 162                 iowrite32(CRB_START_INVOKE, &priv->cca->start);
 163
 164         if (priv->flags & CRB_FL_ACPI_START)
 165                 rc = crb_do_acpi_start(chip);
 166
 167         return rc;
 168 }
 169
 170 static void crb_cancel(struct tpm_chip *chip)
 171 {
 172         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 173
 174         iowrite32(CRB_CANCEL_INVOKE, &priv->cca->cancel);
 175
 176         if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip))
 177                 dev_err(&chip->dev, "ACPI Start failed\n");
 178 }
 179
 180 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
 181 {
 182         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 183         u32 cancel = ioread32(&priv->cca->cancel);
 184
 185         return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
 186 }
 187
 188 static const struct tpm_class_ops tpm_crb = {
 189         .flags = TPM_OPS_AUTO_STARTUP,
 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_DRV_STS_COMPLETE,
 196         .req_complete_val = CRB_DRV_STS_COMPLETE,
 197 };
 198
 199 static int crb_init(struct acpi_device *device, struct crb_priv *priv)
 200 {
 201         struct tpm_chip *chip;
 202
 203         chip = tpmm_chip_alloc(&device->dev, &tpm_crb);
 204         if (IS_ERR(chip))
 205                 return PTR_ERR(chip);
 206
 207         dev_set_drvdata(&chip->dev, priv);
 208         chip->acpi_dev_handle = device->handle;
 209         chip->flags = TPM_CHIP_FLAG_TPM2;
 210
 211         return tpm_chip_register(chip);
 212 }
 213
 214 static int crb_check_resource(struct acpi_resource *ares, void *data)
 215 {
 216         struct resource *io_res = data;
 217         struct resource res;
 218
 219         if (acpi_dev_resource_memory(ares, &res)) {
 220                 *io_res = res;
 221                 io_res->name = NULL;
 222         }
 223
 224         return 1;
 225 }
 226
 227 static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
 228                                  struct resource *io_res, u64 start, u32 size)
 229 {
 230         struct resource new_res = {
 231                 .start  = start,
 232                 .end    = start + size - 1,
 233                 .flags  = IORESOURCE_MEM,
 234         };
 235
 236         /* Detect a 64 bit address on a 32 bit system */
 237         if (start != new_res.start)
 238                 return (void __iomem *) ERR_PTR(-EINVAL);
 239
 240         if (!resource_contains(io_res, &new_res))
 241                 return devm_ioremap_resource(dev, &new_res);
 242
 243         return priv->iobase + (new_res.start - io_res->start);
 244 }
 245
 246 static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
 247                       struct acpi_table_tpm2 *buf)
 248 {
 249         struct list_head resources;
 250         struct resource io_res;
 251         struct device *dev = &device->dev;
 252         u64 cmd_pa;
 253         u32 cmd_size;
 254         u64 rsp_pa;
 255         u32 rsp_size;
 256         int ret;
 257
 258         INIT_LIST_HEAD(&resources);
 259         ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
 260                                      &io_res);
 261         if (ret < 0)
 262                 return ret;
 263         acpi_dev_free_resource_list(&resources);
 264
 265         if (resource_type(&io_res) != IORESOURCE_MEM) {
 266                 dev_err(dev, FW_BUG "TPM2 ACPI table does not define a memory resource\n");
 267                 return -EINVAL;
 268         }
 269
 270         priv->iobase = devm_ioremap_resource(dev, &io_res);
 271         if (IS_ERR(priv->iobase))
 272                 return PTR_ERR(priv->iobase);
 273
 274         priv->cca = crb_map_res(dev, priv, &io_res, buf->control_address,
 275                                 sizeof(struct crb_control_area));
 276         if (IS_ERR(priv->cca))
 277                 return PTR_ERR(priv->cca);
 278
 279         cmd_pa = ((u64) ioread32(&priv->cca->cmd_pa_high) << 32) |
 280                   (u64) ioread32(&priv->cca->cmd_pa_low);
 281         cmd_size = ioread32(&priv->cca->cmd_size);
 282         priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
 283         if (IS_ERR(priv->cmd))
 284                 return PTR_ERR(priv->cmd);
 285
 286         memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8);
 287         rsp_pa = le64_to_cpu(rsp_pa);
 288         rsp_size = ioread32(&priv->cca->rsp_size);
 289
 290         if (cmd_pa != rsp_pa) {
 291                 priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
 292                 return PTR_ERR_OR_ZERO(priv->rsp);
 293         }
 294
 295         /* According to the PTP specification, overlapping command and response
 296          * buffer sizes must be identical.
 297          */
 298         if (cmd_size != rsp_size) {
 299                 dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
 300                 return -EINVAL;
 301         }
 302         priv->cmd_size = cmd_size;
 303
 304         priv->rsp = priv->cmd;
 305         return 0;
 306 }
 307
 308 static int crb_acpi_add(struct acpi_device *device)
 309 {
 310         struct acpi_table_tpm2 *buf;
 311         struct crb_priv *priv;
 312         struct device *dev = &device->dev;
 313         acpi_status status;
 314         u32 sm;
 315         int rc;
 316
 317         status = acpi_get_table(ACPI_SIG_TPM2, 1,
 318                                 (struct acpi_table_header **) &buf);
 319         if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
 320                 dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
 321                 return -EINVAL;
 322         }
 323
 324         /* Should the FIFO driver handle this? */
 325         sm = buf->start_method;
 326         if (sm == ACPI_TPM2_MEMORY_MAPPED)
 327                 return -ENODEV;
 328
 329         priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
 330         if (!priv)
 331                 return -ENOMEM;
 332
 333         /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
 334          * report only ACPI start but in practice seems to require both
 335          * ACPI start and CRB start.
 336          */
 337         if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
 338             !strcmp(acpi_device_hid(device), "MSFT0101"))
 339                 priv->flags |= CRB_FL_CRB_START;
 340
 341         if (sm == ACPI_TPM2_START_METHOD ||
 342             sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
 343                 priv->flags |= CRB_FL_ACPI_START;
 344
 345         rc = crb_map_io(device, priv, buf);
 346         if (rc)
 347                 return rc;
 348
 349         return crb_init(device, priv);
 350 }
 351
 352 static int crb_acpi_remove(struct acpi_device *device)
 353 {
 354         struct device *dev = &device->dev;
 355         struct tpm_chip *chip = dev_get_drvdata(dev);
 356
 357         tpm_chip_unregister(chip);
 358
 359         return 0;
 360 }
 361
 362 static struct acpi_device_id crb_device_ids[] = {
 363         {"MSFT0101", 0},
 364         {"", 0},
 365 };
 366 MODULE_DEVICE_TABLE(acpi, crb_device_ids);
 367
 368 static struct acpi_driver crb_acpi_driver = {
 369         .name = "tpm_crb",
 370         .ids = crb_device_ids,
 371         .ops = {
 372                 .add = crb_acpi_add,
 373                 .remove = crb_acpi_remove,
 374         },
 375         .drv = {
 376                 .pm = &crb_pm,
 377         },
 378 };
 379
 380 module_acpi_driver(crb_acpi_driver);
 381 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
 382 MODULE_DESCRIPTION("TPM2 Driver");
 383 MODULE_VERSION("0.1");
 384 MODULE_LICENSE("GPL");