kernel/drivers/char/tpm/st33zp24/spi.c

   1 /*
   2  * STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
   3  * Copyright (C) 2009 - 2015  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/of_irq.h>
  23 #include <linux/of_gpio.h>
  24 #include <linux/tpm.h>
  25 #include <linux/platform_data/st33zp24.h>
  26
  27 #include "st33zp24.h"
  28
  29 #define TPM_DATA_FIFO           0x24
  30 #define TPM_INTF_CAPABILITY     0x14
  31
  32 #define TPM_DUMMY_BYTE          0x00
  33
  34 #define MAX_SPI_LATENCY         15
  35 #define LOCALITY0               0
  36
  37 #define ST33ZP24_OK                                     0x5A
  38 #define ST33ZP24_UNDEFINED_ERR                          0x80
  39 #define ST33ZP24_BADLOCALITY                            0x81
  40 #define ST33ZP24_TISREGISTER_UKNOWN                     0x82
  41 #define ST33ZP24_LOCALITY_NOT_ACTIVATED                 0x83
  42 #define ST33ZP24_HASH_END_BEFORE_HASH_START             0x84
  43 #define ST33ZP24_BAD_COMMAND_ORDER                      0x85
  44 #define ST33ZP24_INCORECT_RECEIVED_LENGTH               0x86
  45 #define ST33ZP24_TPM_FIFO_OVERFLOW                      0x89
  46 #define ST33ZP24_UNEXPECTED_READ_FIFO                   0x8A
  47 #define ST33ZP24_UNEXPECTED_WRITE_FIFO                  0x8B
  48 #define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END    0x90
  49 #define ST33ZP24_DUMMY_BYTES                            0x00
  50
  51 /*
  52  * TPM command can be up to 2048 byte, A TPM response can be up to
  53  * 1024 byte.
  54  * Between command and response, there are latency byte (up to 15
  55  * usually on st33zp24 2 are enough).
  56  *
  57  * Overall when sending a command and expecting an answer we need if
  58  * worst case:
  59  * 2048 (for the TPM command) + 1024 (for the TPM answer).  We need
  60  * some latency byte before the answer is available (max 15).
  61  * We have 2048 + 1024 + 15.
  62  */
  63 #define ST33ZP24_SPI_BUFFER_SIZE (TPM_BUFSIZE + (TPM_BUFSIZE / 2) +\
  64                                   MAX_SPI_LATENCY)
  65
  66
  67 struct st33zp24_spi_phy {
  68         struct spi_device *spi_device;
  69         struct spi_transfer spi_xfer;
  70         u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
  71         u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];
  72
  73         int io_lpcpd;
  74         int latency;
  75 };
  76
  77 static int st33zp24_status_to_errno(u8 code)
  78 {
  79         switch (code) {
  80         case ST33ZP24_OK:
  81                 return 0;
  82         case ST33ZP24_UNDEFINED_ERR:
  83         case ST33ZP24_BADLOCALITY:
  84         case ST33ZP24_TISREGISTER_UKNOWN:
  85         case ST33ZP24_LOCALITY_NOT_ACTIVATED:
  86         case ST33ZP24_HASH_END_BEFORE_HASH_START:
  87         case ST33ZP24_BAD_COMMAND_ORDER:
  88         case ST33ZP24_UNEXPECTED_READ_FIFO:
  89         case ST33ZP24_UNEXPECTED_WRITE_FIFO:
  90         case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
  91                 return -EPROTO;
  92         case ST33ZP24_INCORECT_RECEIVED_LENGTH:
  93         case ST33ZP24_TPM_FIFO_OVERFLOW:
  94                 return -EMSGSIZE;
  95         case ST33ZP24_DUMMY_BYTES:
  96                 return -ENOSYS;
  97         }
  98         return code;
  99 }
 100
 101 /*
 102  * st33zp24_spi_send
 103  * Send byte to the TIS register according to the ST33ZP24 SPI protocol.
 104  * @param: phy_id, the phy description
 105  * @param: tpm_register, the tpm tis register where the data should be written
 106  * @param: tpm_data, the tpm_data to write inside the tpm_register
 107  * @param: tpm_size, The length of the data
 108  * @return: should be zero if success else a negative error code.
 109  */
 110 static int st33zp24_spi_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
 111                              int tpm_size)
 112 {
 113         u8 data = 0;
 114         int total_length = 0, nbr_dummy_bytes = 0, ret = 0;
 115         struct st33zp24_spi_phy *phy = phy_id;
 116         struct spi_device *dev = phy->spi_device;
 117         u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
 118         u8 *rx_buf = phy->spi_xfer.rx_buf;
 119
 120         /* Pre-Header */
 121         data = TPM_WRITE_DIRECTION | LOCALITY0;
 122         memcpy(tx_buf + total_length, &data, sizeof(data));
 123         total_length++;
 124         data = tpm_register;
 125         memcpy(tx_buf + total_length, &data, sizeof(data));
 126         total_length++;
 127
 128         if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
 129                 tx_buf[total_length++] = tpm_size >> 8;
 130                 tx_buf[total_length++] = tpm_size;
 131         }
 132
 133         memcpy(&tx_buf[total_length], tpm_data, tpm_size);
 134         total_length += tpm_size;
 135
 136         nbr_dummy_bytes = phy->latency;
 137         memset(&tx_buf[total_length], TPM_DUMMY_BYTE, nbr_dummy_bytes);
 138
 139         phy->spi_xfer.len = total_length + nbr_dummy_bytes;
 140
 141         ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
 142         if (ret == 0)
 143                 ret = rx_buf[total_length + nbr_dummy_bytes - 1];
 144
 145         return st33zp24_status_to_errno(ret);
 146 } /* st33zp24_spi_send() */
 147
 148 /*
 149  * read8_recv
 150  * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
 151  * @param: phy_id, the phy description
 152  * @param: tpm_register, the tpm tis register where the data should be read
 153  * @param: tpm_data, the TPM response
 154  * @param: tpm_size, tpm TPM response size to read.
 155  * @return: should be zero if success else a negative error code.
 156  */
 157 static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
 158 {
 159         u8 data = 0;
 160         int total_length = 0, nbr_dummy_bytes, ret;
 161         struct st33zp24_spi_phy *phy = phy_id;
 162         struct spi_device *dev = phy->spi_device;
 163         u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
 164         u8 *rx_buf = phy->spi_xfer.rx_buf;
 165
 166         /* Pre-Header */
 167         data = LOCALITY0;
 168         memcpy(tx_buf + total_length, &data, sizeof(data));
 169         total_length++;
 170         data = tpm_register;
 171         memcpy(tx_buf + total_length, &data, sizeof(data));
 172         total_length++;
 173
 174         nbr_dummy_bytes = phy->latency;
 175         memset(&tx_buf[total_length], TPM_DUMMY_BYTE,
 176                nbr_dummy_bytes + tpm_size);
 177
 178         phy->spi_xfer.len = total_length + nbr_dummy_bytes + tpm_size;
 179
 180         /* header + status byte + size of the data + status byte */
 181         ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
 182         if (tpm_size > 0 && ret == 0) {
 183                 ret = rx_buf[total_length + nbr_dummy_bytes - 1];
 184
 185                 memcpy(tpm_data, rx_buf + total_length + nbr_dummy_bytes,
 186                        tpm_size);
 187         }
 188
 189         return ret;
 190 } /* read8_reg() */
 191
 192 /*
 193  * st33zp24_spi_recv
 194  * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
 195  * @param: phy_id, the phy description
 196  * @param: tpm_register, the tpm tis register where the data should be read
 197  * @param: tpm_data, the TPM response
 198  * @param: tpm_size, tpm TPM response size to read.
 199  * @return: number of byte read successfully: should be one if success.
 200  */
 201 static int st33zp24_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
 202                              int tpm_size)
 203 {
 204         int ret;
 205
 206         ret = read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
 207         if (!st33zp24_status_to_errno(ret))
 208                 return tpm_size;
 209         return ret;
 210 } /* st33zp24_spi_recv() */
 211
 212 static int evaluate_latency(void *phy_id)
 213 {
 214         struct st33zp24_spi_phy *phy = phy_id;
 215         int latency = 1, status = 0;
 216         u8 data = 0;
 217
 218         while (!status && latency < MAX_SPI_LATENCY) {
 219                 phy->latency = latency;
 220                 status = read8_reg(phy_id, TPM_INTF_CAPABILITY, &data, 1);
 221                 latency++;
 222         }
 223         return latency - 1;
 224 } /* evaluate_latency() */
 225
 226 static const struct st33zp24_phy_ops spi_phy_ops = {
 227         .send = st33zp24_spi_send,
 228         .recv = st33zp24_spi_recv,
 229 };
 230
 231 #ifdef CONFIG_OF
 232 static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy)
 233 {
 234         struct device_node *pp;
 235         struct spi_device *dev = phy->spi_device;
 236         int gpio;
 237         int ret;
 238
 239         pp = dev->dev.of_node;
 240         if (!pp) {
 241                 dev_err(&dev->dev, "No platform data\n");
 242                 return -ENODEV;
 243         }
 244
 245         /* Get GPIO from device tree */
 246         gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0);
 247         if (gpio < 0) {
 248                 dev_err(&dev->dev,
 249                         "Failed to retrieve lpcpd-gpios from dts.\n");
 250                 phy->io_lpcpd = -1;
 251                 /*
 252                  * lpcpd pin is not specified. This is not an issue as
 253                  * power management can be also managed by TPM specific
 254                  * commands. So leave with a success status code.
 255                  */
 256                 return 0;
 257         }
 258         /* GPIO request and configuration */
 259         ret = devm_gpio_request_one(&dev->dev, gpio,
 260                         GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
 261         if (ret) {
 262                 dev_err(&dev->dev, "Failed to request lpcpd pin\n");
 263                 return -ENODEV;
 264         }
 265         phy->io_lpcpd = gpio;
 266
 267         return 0;
 268 }
 269 #else
 270 static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy)
 271 {
 272         return -ENODEV;
 273 }
 274 #endif
 275
 276 static int tpm_stm_spi_request_resources(struct spi_device *dev,
 277                                          struct st33zp24_spi_phy *phy)
 278 {
 279         struct st33zp24_platform_data *pdata;
 280         int ret;
 281
 282         pdata = dev->dev.platform_data;
 283         if (!pdata) {
 284                 dev_err(&dev->dev, "No platform data\n");
 285                 return -ENODEV;
 286         }
 287
 288         /* store for late use */
 289         phy->io_lpcpd = pdata->io_lpcpd;
 290
 291         if (gpio_is_valid(pdata->io_lpcpd)) {
 292                 ret = devm_gpio_request_one(&dev->dev,
 293                                 pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH,
 294                                 "TPM IO_LPCPD");
 295                 if (ret) {
 296                         dev_err(&dev->dev, "%s : reset gpio_request failed\n",
 297                                 __FILE__);
 298                         return ret;
 299                 }
 300         }
 301
 302         return 0;
 303 }
 304
 305 /*
 306  * tpm_st33_spi_probe initialize the TPM device
 307  * @param: dev, the spi_device drescription (TPM SPI description).
 308  * @return: 0 in case of success.
 309  *       or a negative value describing the error.
 310  */
 311 static int
 312 tpm_st33_spi_probe(struct spi_device *dev)
 313 {
 314         int ret;
 315         struct st33zp24_platform_data *pdata;
 316         struct st33zp24_spi_phy *phy;
 317
 318         /* Check SPI platform functionnalities */
 319         if (!dev) {
 320                 pr_info("%s: dev is NULL. Device is not accessible.\n",
 321                         __func__);
 322                 return -ENODEV;
 323         }
 324
 325         phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy),
 326                            GFP_KERNEL);
 327         if (!phy)
 328                 return -ENOMEM;
 329
 330         phy->spi_device = dev;
 331         pdata = dev->dev.platform_data;
 332         if (!pdata && dev->dev.of_node) {
 333                 ret = tpm_stm_spi_of_request_resources(phy);
 334                 if (ret)
 335                         return ret;
 336         } else if (pdata) {
 337                 ret = tpm_stm_spi_request_resources(dev, phy);
 338                 if (ret)
 339                         return ret;
 340         }
 341
 342         phy->spi_xfer.tx_buf = phy->tx_buf;
 343         phy->spi_xfer.rx_buf = phy->rx_buf;
 344
 345         phy->latency = evaluate_latency(phy);
 346         if (phy->latency <= 0)
 347                 return -ENODEV;
 348
 349         return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq,
 350                               phy->io_lpcpd);
 351 }
 352
 353 /*
 354  * tpm_st33_spi_remove remove the TPM device
 355  * @param: client, the spi_device drescription (TPM SPI description).
 356  * @return: 0 in case of success.
 357  */
 358 static int tpm_st33_spi_remove(struct spi_device *dev)
 359 {
 360         struct tpm_chip *chip = spi_get_drvdata(dev);
 361
 362         return st33zp24_remove(chip);
 363 }
 364
 365 static const struct spi_device_id st33zp24_spi_id[] = {
 366         {TPM_ST33_SPI, 0},
 367         {}
 368 };
 369 MODULE_DEVICE_TABLE(spi, st33zp24_spi_id);
 370
 371 #ifdef CONFIG_OF
 372 static const struct of_device_id of_st33zp24_spi_match[] = {
 373         { .compatible = "st,st33zp24-spi", },
 374         {}
 375 };
 376 MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match);
 377 #endif
 378
 379 static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
 380                          st33zp24_pm_resume);
 381
 382 static struct spi_driver tpm_st33_spi_driver = {
 383         .driver = {
 384                 .owner = THIS_MODULE,
 385                 .name = TPM_ST33_SPI,
 386                 .pm = &st33zp24_spi_ops,
 387                 .of_match_table = of_match_ptr(of_st33zp24_spi_match),
 388         },
 389         .probe = tpm_st33_spi_probe,
 390         .remove = tpm_st33_spi_remove,
 391         .id_table = st33zp24_spi_id,
 392 };
 393
 394 module_spi_driver(tpm_st33_spi_driver);
 395
 396 MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
 397 MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
 398 MODULE_VERSION("1.3.0");
 399 MODULE_LICENSE("GPL");