drivers/char/tpm/st33zp24/spi.c

   1 /*
   2  * STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
   3  * Copyright (C) 2009 - 2016 STMicroelectronics
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/spi/spi.h>
  21 #include <linux/gpio.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/of_irq.h>
  24 #include <linux/of_gpio.h>
  25 #include <linux/acpi.h>
  26 #include <linux/tpm.h>
  27 #include <linux/platform_data/st33zp24.h>
  28
  29 #include "../tpm.h"
  30 #include "st33zp24.h"
  31
  32 #define TPM_DATA_FIFO           0x24
  33 #define TPM_INTF_CAPABILITY     0x14
  34
  35 #define TPM_DUMMY_BYTE          0x00
  36
  37 #define MAX_SPI_LATENCY         15
  38 #define LOCALITY0               0
  39
  40 #define ST33ZP24_OK                                     0x5A
  41 #define ST33ZP24_UNDEFINED_ERR                          0x80
  42 #define ST33ZP24_BADLOCALITY                            0x81
  43 #define ST33ZP24_TISREGISTER_UKNOWN                     0x82
  44 #define ST33ZP24_LOCALITY_NOT_ACTIVATED                 0x83
  45 #define ST33ZP24_HASH_END_BEFORE_HASH_START             0x84
  46 #define ST33ZP24_BAD_COMMAND_ORDER                      0x85
  47 #define ST33ZP24_INCORECT_RECEIVED_LENGTH               0x86
  48 #define ST33ZP24_TPM_FIFO_OVERFLOW                      0x89
  49 #define ST33ZP24_UNEXPECTED_READ_FIFO                   0x8A
  50 #define ST33ZP24_UNEXPECTED_WRITE_FIFO                  0x8B
  51 #define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END    0x90
  52 #define ST33ZP24_DUMMY_BYTES                            0x00
  53
  54 /*
  55  * TPM command can be up to 2048 byte, A TPM response can be up to
  56  * 1024 byte.
  57  * Between command and response, there are latency byte (up to 15
  58  * usually on st33zp24 2 are enough).
  59  *
  60  * Overall when sending a command and expecting an answer we need if
  61  * worst case:
  62  * 2048 (for the TPM command) + 1024 (for the TPM answer).  We need
  63  * some latency byte before the answer is available (max 15).
  64  * We have 2048 + 1024 + 15.
  65  */
  66 #define ST33ZP24_SPI_BUFFER_SIZE (TPM_BUFSIZE + (TPM_BUFSIZE / 2) +\
  67                                   MAX_SPI_LATENCY)
  68
  69
  70 struct st33zp24_spi_phy {
  71         struct spi_device *spi_device;
  72
  73         u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
  74         u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];
  75
  76         int io_lpcpd;
  77         int latency;
  78 };
  79
  80 static int st33zp24_status_to_errno(u8 code)
  81 {
  82         switch (code) {
  83         case ST33ZP24_OK:
  84                 return 0;
  85         case ST33ZP24_UNDEFINED_ERR:
  86         case ST33ZP24_BADLOCALITY:
  87         case ST33ZP24_TISREGISTER_UKNOWN:
  88         case ST33ZP24_LOCALITY_NOT_ACTIVATED:
  89         case ST33ZP24_HASH_END_BEFORE_HASH_START:
  90         case ST33ZP24_BAD_COMMAND_ORDER:
  91         case ST33ZP24_UNEXPECTED_READ_FIFO:
  92         case ST33ZP24_UNEXPECTED_WRITE_FIFO:
  93         case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
  94                 return -EPROTO;
  95         case ST33ZP24_INCORECT_RECEIVED_LENGTH:
  96         case ST33ZP24_TPM_FIFO_OVERFLOW:
  97                 return -EMSGSIZE;
  98         case ST33ZP24_DUMMY_BYTES:
  99                 return -ENOSYS;
 100         }
 101         return code;
 102 }
 103
 104 /*
 105  * st33zp24_spi_send
 106  * Send byte to the TIS register according to the ST33ZP24 SPI protocol.
 107  * @param: phy_id, the phy description
 108  * @param: tpm_register, the tpm tis register where the data should be written
 109  * @param: tpm_data, the tpm_data to write inside the tpm_register
 110  * @param: tpm_size, The length of the data
 111  * @return: should be zero if success else a negative error code.
 112  */
 113 static int st33zp24_spi_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
 114                              int tpm_size)
 115 {
 116         int total_length = 0, ret = 0;
 117         struct st33zp24_spi_phy *phy = phy_id;
 118         struct spi_device *dev = phy->spi_device;
 119         struct spi_transfer spi_xfer = {
 120                 .tx_buf = phy->tx_buf,
 121                 .rx_buf = phy->rx_buf,
 122         };
 123
 124         /* Pre-Header */
 125         phy->tx_buf[total_length++] = TPM_WRITE_DIRECTION | LOCALITY0;
 126         phy->tx_buf[total_length++] = tpm_register;
 127
 128         if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
 129                 phy->tx_buf[total_length++] = tpm_size >> 8;
 130                 phy->tx_buf[total_length++] = tpm_size;
 131         }
 132
 133         memcpy(&phy->tx_buf[total_length], tpm_data, tpm_size);
 134         total_length += tpm_size;
 135
 136         memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE, phy->latency);
 137
 138         spi_xfer.len = total_length + phy->latency;
 139
 140         ret = spi_sync_transfer(dev, &spi_xfer, 1);
 141         if (ret == 0)
 142                 ret = phy->rx_buf[total_length + phy->latency - 1];
 143
 144         return st33zp24_status_to_errno(ret);
 145 } /* st33zp24_spi_send() */
 146
 147 /*
 148  * st33zp24_spi_read8_recv
 149  * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
 150  * @param: phy_id, the phy description
 151  * @param: tpm_register, the tpm tis register where the data should be read
 152  * @param: tpm_data, the TPM response
 153  * @param: tpm_size, tpm TPM response size to read.
 154  * @return: should be zero if success else a negative error code.
 155  */
 156 static int st33zp24_spi_read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data,
 157                                   int tpm_size)
 158 {
 159         int total_length = 0, ret;
 160         struct st33zp24_spi_phy *phy = phy_id;
 161         struct spi_device *dev = phy->spi_device;
 162         struct spi_transfer spi_xfer = {
 163                 .tx_buf = phy->tx_buf,
 164                 .rx_buf = phy->rx_buf,
 165         };
 166
 167         /* Pre-Header */
 168         phy->tx_buf[total_length++] = LOCALITY0;
 169         phy->tx_buf[total_length++] = tpm_register;
 170
 171         memset(&phy->tx_buf[total_length], TPM_DUMMY_BYTE,
 172                phy->latency + tpm_size);
 173
 174         spi_xfer.len = total_length + phy->latency + tpm_size;
 175
 176         /* header + status byte + size of the data + status byte */
 177         ret = spi_sync_transfer(dev, &spi_xfer, 1);
 178         if (tpm_size > 0 && ret == 0) {
 179                 ret = phy->rx_buf[total_length + phy->latency - 1];
 180
 181                 memcpy(tpm_data, phy->rx_buf + total_length + phy->latency,
 182                        tpm_size);
 183         }
 184
 185         return ret;
 186 } /* st33zp24_spi_read8_reg() */
 187
 188 /*
 189  * st33zp24_spi_recv
 190  * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
 191  * @param: phy_id, the phy description
 192  * @param: tpm_register, the tpm tis register where the data should be read
 193  * @param: tpm_data, the TPM response
 194  * @param: tpm_size, tpm TPM response size to read.
 195  * @return: number of byte read successfully: should be one if success.
 196  */
 197 static int st33zp24_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
 198                              int tpm_size)
 199 {
 200         int ret;
 201
 202         ret = st33zp24_spi_read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
 203         if (!st33zp24_status_to_errno(ret))
 204                 return tpm_size;
 205         return ret;
 206 } /* st33zp24_spi_recv() */
 207
 208 static int st33zp24_spi_evaluate_latency(void *phy_id)
 209 {
 210         struct st33zp24_spi_phy *phy = phy_id;
 211         int latency = 1, status = 0;
 212         u8 data = 0;
 213
 214         while (!status && latency < MAX_SPI_LATENCY) {
 215                 phy->latency = latency;
 216                 status = st33zp24_spi_read8_reg(phy_id, TPM_INTF_CAPABILITY,
 217                                                 &data, 1);
 218                 latency++;
 219         }
 220         if (status < 0)
 221                 return status;
 222         if (latency == MAX_SPI_LATENCY)
 223                 return -ENODEV;
 224
 225         return latency - 1;
 226 } /* evaluate_latency() */
 227
 228 static const struct st33zp24_phy_ops spi_phy_ops = {
 229         .send = st33zp24_spi_send,
 230         .recv = st33zp24_spi_recv,
 231 };
 232
 233 static int st33zp24_spi_acpi_request_resources(struct spi_device *spi_dev)
 234 {
 235         struct tpm_chip *chip = spi_get_drvdata(spi_dev);
 236         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 237         struct st33zp24_spi_phy *phy = tpm_dev->phy_id;
 238         struct gpio_desc *gpiod_lpcpd;
 239         struct device *dev = &spi_dev->dev;
 240
 241         /* Get LPCPD GPIO from ACPI */
 242         gpiod_lpcpd = devm_gpiod_get_index(dev, "TPM IO LPCPD", 1,
 243                                            GPIOD_OUT_HIGH);
 244         if (IS_ERR(gpiod_lpcpd)) {
 245                 dev_err(dev, "Failed to retrieve lpcpd-gpios from acpi.\n");
 246                 phy->io_lpcpd = -1;
 247                 /*
 248                  * lpcpd pin is not specified. This is not an issue as
 249                  * power management can be also managed by TPM specific
 250                  * commands. So leave with a success status code.
 251                  */
 252                 return 0;
 253         }
 254
 255         phy->io_lpcpd = desc_to_gpio(gpiod_lpcpd);
 256
 257         return 0;
 258 }
 259
 260 static int st33zp24_spi_of_request_resources(struct spi_device *spi_dev)
 261 {
 262         struct tpm_chip *chip = spi_get_drvdata(spi_dev);
 263         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 264         struct st33zp24_spi_phy *phy = tpm_dev->phy_id;
 265         struct device_node *pp;
 266         int gpio;
 267         int ret;
 268
 269         pp = spi_dev->dev.of_node;
 270         if (!pp) {
 271                 dev_err(&spi_dev->dev, "No platform data\n");
 272                 return -ENODEV;
 273         }
 274
 275         /* Get GPIO from device tree */
 276         gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0);
 277         if (gpio < 0) {
 278                 dev_err(&spi_dev->dev,
 279                         "Failed to retrieve lpcpd-gpios from dts.\n");
 280                 phy->io_lpcpd = -1;
 281                 /*
 282                  * lpcpd pin is not specified. This is not an issue as
 283                  * power management can be also managed by TPM specific
 284                  * commands. So leave with a success status code.
 285                  */
 286                 return 0;
 287         }
 288         /* GPIO request and configuration */
 289         ret = devm_gpio_request_one(&spi_dev->dev, gpio,
 290                         GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
 291         if (ret) {
 292                 dev_err(&spi_dev->dev, "Failed to request lpcpd pin\n");
 293                 return -ENODEV;
 294         }
 295         phy->io_lpcpd = gpio;
 296
 297         return 0;
 298 }
 299
 300 static int st33zp24_spi_request_resources(struct spi_device *dev)
 301 {
 302         struct tpm_chip *chip = spi_get_drvdata(dev);
 303         struct st33zp24_dev *tpm_dev = dev_get_drvdata(&chip->dev);
 304         struct st33zp24_spi_phy *phy = tpm_dev->phy_id;
 305         struct st33zp24_platform_data *pdata;
 306         int ret;
 307
 308         pdata = dev->dev.platform_data;
 309         if (!pdata) {
 310                 dev_err(&dev->dev, "No platform data\n");
 311                 return -ENODEV;
 312         }
 313
 314         /* store for late use */
 315         phy->io_lpcpd = pdata->io_lpcpd;
 316
 317         if (gpio_is_valid(pdata->io_lpcpd)) {
 318                 ret = devm_gpio_request_one(&dev->dev,
 319                                 pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH,
 320                                 "TPM IO_LPCPD");
 321                 if (ret) {
 322                         dev_err(&dev->dev, "%s : reset gpio_request failed\n",
 323                                 __FILE__);
 324                         return ret;
 325                 }
 326         }
 327
 328         return 0;
 329 }
 330
 331 /*
 332  * st33zp24_spi_probe initialize the TPM device
 333  * @param: dev, the spi_device drescription (TPM SPI description).
 334  * @return: 0 in case of success.
 335  *       or a negative value describing the error.
 336  */
 337 static int st33zp24_spi_probe(struct spi_device *dev)
 338 {
 339         int ret;
 340         struct st33zp24_platform_data *pdata;
 341         struct st33zp24_spi_phy *phy;
 342
 343         /* Check SPI platform functionnalities */
 344         if (!dev) {
 345                 pr_info("%s: dev is NULL. Device is not accessible.\n",
 346                         __func__);
 347                 return -ENODEV;
 348         }
 349
 350         phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy),
 351                            GFP_KERNEL);
 352         if (!phy)
 353                 return -ENOMEM;
 354
 355         phy->spi_device = dev;
 356
 357         pdata = dev->dev.platform_data;
 358         if (!pdata && dev->dev.of_node) {
 359                 ret = st33zp24_spi_of_request_resources(dev);
 360                 if (ret)
 361                         return ret;
 362         } else if (pdata) {
 363                 ret = st33zp24_spi_request_resources(dev);
 364                 if (ret)
 365                         return ret;
 366         } else if (ACPI_HANDLE(&dev->dev)) {
 367                 ret = st33zp24_spi_acpi_request_resources(dev);
 368                 if (ret)
 369                         return ret;
 370         }
 371
 372         phy->latency = st33zp24_spi_evaluate_latency(phy);
 373         if (phy->latency <= 0)
 374                 return -ENODEV;
 375
 376         return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq,
 377                               phy->io_lpcpd);
 378 }
 379
 380 /*
 381  * st33zp24_spi_remove remove the TPM device
 382  * @param: client, the spi_device drescription (TPM SPI description).
 383  * @return: 0 in case of success.
 384  */
 385 static int st33zp24_spi_remove(struct spi_device *dev)
 386 {
 387         struct tpm_chip *chip = spi_get_drvdata(dev);
 388
 389         return st33zp24_remove(chip);
 390 }
 391
 392 static const struct spi_device_id st33zp24_spi_id[] = {
 393         {TPM_ST33_SPI, 0},
 394         {}
 395 };
 396 MODULE_DEVICE_TABLE(spi, st33zp24_spi_id);
 397
 398 static const struct of_device_id of_st33zp24_spi_match[] = {
 399         { .compatible = "st,st33zp24-spi", },
 400         {}
 401 };
 402 MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match);
 403
 404 static const struct acpi_device_id st33zp24_spi_acpi_match[] = {
 405         {"SMO3324"},
 406         {}
 407 };
 408 MODULE_DEVICE_TABLE(acpi, st33zp24_spi_acpi_match);
 409
 410 static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
 411                          st33zp24_pm_resume);
 412
 413 static struct spi_driver st33zp24_spi_driver = {
 414         .driver = {
 415                 .name = TPM_ST33_SPI,
 416                 .pm = &st33zp24_spi_ops,
 417                 .of_match_table = of_match_ptr(of_st33zp24_spi_match),
 418                 .acpi_match_table = ACPI_PTR(st33zp24_spi_acpi_match),
 419         },
 420         .probe = st33zp24_spi_probe,
 421         .remove = st33zp24_spi_remove,
 422         .id_table = st33zp24_spi_id,
 423 };
 424
 425 module_spi_driver(st33zp24_spi_driver);
 426
 427 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
 428 MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
 429 MODULE_VERSION("1.3.0");
 430 MODULE_LICENSE("GPL");