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         void __iomem *iobase;
  81         struct crb_control_area __iomem *cca;
  82         u8 __iomem *cmd;
  83         u8 __iomem *rsp;
  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_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_CA_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         if (len > ioread32(&priv->cca->cmd_size)) {
 146                 dev_err(&chip->dev,
 147                         "invalid command count value %x %zx\n",
 148                         (unsigned int) len,
 149                         (size_t) ioread32(&priv->cca->cmd_size));
 150                 return -E2BIG;
 151         }
 152
 153         memcpy_toio(priv->cmd, buf, len);
 154
 155         /* Make sure that cmd is populated before issuing start. */
 156         wmb();
 157
 158         if (priv->flags & CRB_FL_CRB_START)
 159                 iowrite32(cpu_to_le32(CRB_START_INVOKE), &priv->cca->start);
 160
 161         if (priv->flags & CRB_FL_ACPI_START)
 162                 rc = crb_do_acpi_start(chip);
 163
 164         return rc;
 165 }
 166
 167 static void crb_cancel(struct tpm_chip *chip)
 168 {
 169         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 170
 171         iowrite32(cpu_to_le32(CRB_CANCEL_INVOKE), &priv->cca->cancel);
 172
 173         /* Make sure that cmd is populated before issuing cancel. */
 174         wmb();
 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         iowrite32(0, &priv->cca->cancel);
 180 }
 181
 182 static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
 183 {
 184         struct crb_priv *priv = dev_get_drvdata(&chip->dev);
 185         u32 cancel = ioread32(&priv->cca->cancel);
 186
 187         return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
 188 }
 189
 190 static const struct tpm_class_ops tpm_crb = {
 191         .flags = TPM_OPS_AUTO_STARTUP,
 192         .status = crb_status,
 193         .recv = crb_recv,
 194         .send = crb_send,
 195         .cancel = crb_cancel,
 196         .req_canceled = crb_req_canceled,
 197         .req_complete_mask = CRB_STS_COMPLETE,
 198         .req_complete_val = CRB_STS_COMPLETE,
 199 };
 200
 201 static int crb_init(struct acpi_device *device, struct crb_priv *priv)
 202 {
 203         struct tpm_chip *chip;
 204
 205         chip = tpmm_chip_alloc(&device->dev, &tpm_crb);
 206         if (IS_ERR(chip))
 207                 return PTR_ERR(chip);
 208
 209         dev_set_drvdata(&chip->dev, priv);
 210         chip->acpi_dev_handle = device->handle;
 211         chip->flags = TPM_CHIP_FLAG_TPM2;
 212
 213         return tpm_chip_register(chip);
 214 }
 215
 216 static int crb_check_resource(struct acpi_resource *ares, void *data)
 217 {
 218         struct resource *io_res = data;
 219         struct resource res;
 220
 221         if (acpi_dev_resource_memory(ares, &res)) {
 222                 *io_res = res;
 223                 io_res->name = NULL;
 224         }
 225
 226         return 1;
 227 }
 228
 229 static void __iomem *crb_map_res(struct device *dev, struct crb_priv *priv,
 230                                  struct resource *io_res, u64 start, u32 size)
 231 {
 232         struct resource new_res = {
 233                 .start  = start,
 234                 .end    = start + size - 1,
 235                 .flags  = IORESOURCE_MEM,
 236         };
 237
 238         /* Detect a 64 bit address on a 32 bit system */
 239         if (start != new_res.start)
 240                 return (void __iomem *) ERR_PTR(-EINVAL);
 241
 242         if (!resource_contains(io_res, &new_res))
 243                 return devm_ioremap_resource(dev, &new_res);
 244
 245         return priv->iobase + (new_res.start - io_res->start);
 246 }
 247
 248 static int crb_map_io(struct acpi_device *device, struct crb_priv *priv,
 249                       struct acpi_table_tpm2 *buf)
 250 {
 251         struct list_head resources;
 252         struct resource io_res;
 253         struct device *dev = &device->dev;
 254         u64 cmd_pa;
 255         u32 cmd_size;
 256         u64 rsp_pa;
 257         u32 rsp_size;
 258         int ret;
 259
 260         INIT_LIST_HEAD(&resources);
 261         ret = acpi_dev_get_resources(device, &resources, crb_check_resource,
 262                                      &io_res);
 263         if (ret < 0)
 264                 return ret;
 265         acpi_dev_free_resource_list(&resources);
 266
 267         if (resource_type(&io_res) != IORESOURCE_MEM) {
 268                 dev_err(dev,
 269                         FW_BUG "TPM2 ACPI table does not define a memory resource\n");
 270                 return -EINVAL;
 271         }
 272
 273         priv->iobase = devm_ioremap_resource(dev, &io_res);
 274         if (IS_ERR(priv->iobase))
 275                 return PTR_ERR(priv->iobase);
 276
 277         priv->cca = crb_map_res(dev, priv, &io_res, buf->control_address,
 278                                 sizeof(struct crb_control_area));
 279         if (IS_ERR(priv->cca))
 280                 return PTR_ERR(priv->cca);
 281
 282         cmd_pa = ((u64) ioread32(&priv->cca->cmd_pa_high) << 32) |
 283                   (u64) ioread32(&priv->cca->cmd_pa_low);
 284         cmd_size = ioread32(&priv->cca->cmd_size);
 285         priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size);
 286         if (IS_ERR(priv->cmd))
 287                 return PTR_ERR(priv->cmd);
 288
 289         memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8);
 290         rsp_pa = le64_to_cpu(rsp_pa);
 291         rsp_size = ioread32(&priv->cca->rsp_size);
 292
 293         if (cmd_pa != rsp_pa) {
 294                 priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size);
 295                 return PTR_ERR_OR_ZERO(priv->rsp);
 296         }
 297
 298         /* According to the PTP specification, overlapping command and response
 299          * buffer sizes must be identical.
 300          */
 301         if (cmd_size != rsp_size) {
 302                 dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical");
 303                 return -EINVAL;
 304         }
 305
 306         priv->rsp = priv->cmd;
 307         return 0;
 308 }
 309
 310 static int crb_acpi_add(struct acpi_device *device)
 311 {
 312         struct acpi_table_tpm2 *buf;
 313         struct crb_priv *priv;
 314         struct device *dev = &device->dev;
 315         acpi_status status;
 316         u32 sm;
 317         int rc;
 318
 319         status = acpi_get_table(ACPI_SIG_TPM2, 1,
 320                                 (struct acpi_table_header **) &buf);
 321         if (ACPI_FAILURE(status) || buf->header.length < sizeof(*buf)) {
 322                 dev_err(dev, FW_BUG "failed to get TPM2 ACPI table\n");
 323                 return -EINVAL;
 324         }
 325
 326         /* Should the FIFO driver handle this? */
 327         sm = buf->start_method;
 328         if (sm == ACPI_TPM2_MEMORY_MAPPED)
 329                 return -ENODEV;
 330
 331         priv = devm_kzalloc(dev, sizeof(struct crb_priv), GFP_KERNEL);
 332         if (!priv)
 333                 return -ENOMEM;
 334
 335         /* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
 336          * report only ACPI start but in practice seems to require both
 337          * ACPI start and CRB start.
 338          */
 339         if (sm == ACPI_TPM2_COMMAND_BUFFER || sm == ACPI_TPM2_MEMORY_MAPPED ||
 340             !strcmp(acpi_device_hid(device), "MSFT0101"))
 341                 priv->flags |= CRB_FL_CRB_START;
 342
 343         if (sm == ACPI_TPM2_START_METHOD ||
 344             sm == ACPI_TPM2_COMMAND_BUFFER_WITH_START_METHOD)
 345                 priv->flags |= CRB_FL_ACPI_START;
 346
 347         rc = crb_map_io(device, priv, buf);
 348         if (rc)
 349                 return rc;
 350
 351         return crb_init(device, priv);
 352 }
 353
 354 static int crb_acpi_remove(struct acpi_device *device)
 355 {
 356         struct device *dev = &device->dev;
 357         struct tpm_chip *chip = dev_get_drvdata(dev);
 358
 359         tpm_chip_unregister(chip);
 360
 361         return 0;
 362 }
 363
 364 static struct acpi_device_id crb_device_ids[] = {
 365         {"MSFT0101", 0},
 366         {"", 0},
 367 };
 368 MODULE_DEVICE_TABLE(acpi, crb_device_ids);
 369
 370 static struct acpi_driver crb_acpi_driver = {
 371         .name = "tpm_crb",
 372         .ids = crb_device_ids,
 373         .ops = {
 374                 .add = crb_acpi_add,
 375                 .remove = crb_acpi_remove,
 376         },
 377         .drv = {
 378                 .pm = &crb_pm,
 379         },
 380 };
 381
 382 module_acpi_driver(crb_acpi_driver);
 383 MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
 384 MODULE_DESCRIPTION("TPM2 Driver");
 385 MODULE_VERSION("0.1");
 386 MODULE_LICENSE("GPL");