drivers/tpm/tpm2_tis_spi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Author:
   4  * Miquel Raynal <[email protected]>
   5  *
   6  * Description:
   7  * SPI-level driver for TCG/TIS TPM (trusted platform module).
   8  * Specifications at www.trustedcomputinggroup.org
   9  *
  10  * This device driver implements the TPM interface as defined in
  11  * the TCG SPI protocol stack version 2.0.
  12  *
  13  * It is based on the U-Boot driver tpm_tis_infineon_i2c.c.
  14  */
  15
  16 #include <dm.h>
  17 #include <fdtdec.h>
  18 #include <log.h>
  19 #include <spi.h>
  20 #include <time.h>
  21 #include <tpm-v2.h>
  22 #include <linux/bitops.h>
  23 #include <linux/delay.h>
  24 #include <linux/errno.h>
  25 #include <linux/compiler.h>
  26 #include <linux/types.h>
  27 #include <linux/unaligned/be_byteshift.h>
  28 #include <asm-generic/gpio.h>
  29
  30 #include "tpm_tis.h"
  31 #include "tpm_internal.h"
  32
  33 #define MAX_SPI_FRAMESIZE 64
  34
  35 /* Number of wait states to wait for */
  36 #define TPM_WAIT_STATES 100
  37
  38 /**
  39  * struct tpm_tis_chip_data - Non-discoverable TPM information
  40  *
  41  * @pcr_count:          Number of PCR per bank
  42  * @pcr_select_min:     Size in octets of the pcrSelect array
  43  */
  44 struct tpm_tis_chip_data {
  45         unsigned int pcr_count;
  46         unsigned int pcr_select_min;
  47         unsigned int time_before_first_cmd_ms;
  48 };
  49
  50 /**
  51  * tpm_tis_spi_read() - Read from TPM register
  52  *
  53  * @addr: register address to read from
  54  * @buffer: provided by caller
  55  * @len: number of bytes to read
  56  *
  57  * Read len bytes from TPM register and put them into
  58  * buffer (little-endian format, i.e. first byte is put into buffer[0]).
  59  *
  60  * NOTE: TPM is big-endian for multi-byte values. Multi-byte
  61  * values have to be swapped.
  62  *
  63  * Return: -EIO on error, 0 on success.
  64  */
  65 static int tpm_tis_spi_xfer(struct udevice *dev, u32 addr, const u8 *out,
  66                             u8 *in, u16 len)
  67 {
  68         struct spi_slave *slave = dev_get_parent_priv(dev);
  69         int transfer_len, ret;
  70         u8 tx_buf[MAX_SPI_FRAMESIZE];
  71         u8 rx_buf[MAX_SPI_FRAMESIZE];
  72
  73         if (in && out) {
  74                 log(LOGC_NONE, LOGL_ERR, "%s: can't do full duplex\n",
  75                     __func__);
  76                 return -EINVAL;
  77         }
  78
  79         ret = spi_claim_bus(slave);
  80         if (ret < 0) {
  81                 log(LOGC_NONE, LOGL_ERR, "%s: could not claim bus\n", __func__);
  82                 return ret;
  83         }
  84
  85         while (len) {
  86                 /* Request */
  87                 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
  88                 tx_buf[0] = (in ? BIT(7) : 0) | (transfer_len - 1);
  89                 tx_buf[1] = 0xD4;
  90                 tx_buf[2] = addr >> 8;
  91                 tx_buf[3] = addr;
  92
  93                 ret = spi_xfer(slave, 4 * 8, tx_buf, rx_buf, SPI_XFER_BEGIN);
  94                 if (ret < 0) {
  95                         log(LOGC_NONE, LOGL_ERR,
  96                             "%s: spi request transfer failed (err: %d)\n",
  97                             __func__, ret);
  98                         goto release_bus;
  99                 }
 100
 101                 /* Wait state */
 102                 if (!(rx_buf[3] & 0x1)) {
 103                         int i;
 104
 105                         for (i = 0; i < TPM_WAIT_STATES; i++) {
 106                                 ret = spi_xfer(slave, 1 * 8, NULL, rx_buf, 0);
 107                                 if (ret) {
 108                                         log(LOGC_NONE, LOGL_ERR,
 109                                             "%s: wait state failed: %d\n",
 110                                             __func__, ret);
 111                                         goto release_bus;
 112                                 }
 113
 114                                 if (rx_buf[0] & 0x1)
 115                                         break;
 116                         }
 117
 118                         if (i == TPM_WAIT_STATES) {
 119                                 log(LOGC_NONE, LOGL_ERR,
 120                                     "%s: timeout on wait state\n", __func__);
 121                                 ret = -ETIMEDOUT;
 122                                 goto release_bus;
 123                         }
 124                 }
 125
 126                 /* Read/Write */
 127                 if (out) {
 128                         memcpy(tx_buf, out, transfer_len);
 129                         out += transfer_len;
 130                 }
 131
 132                 ret = spi_xfer(slave, transfer_len * 8,
 133                                out ? tx_buf : NULL,
 134                                in ? rx_buf : NULL,
 135                                SPI_XFER_END);
 136                 if (ret) {
 137                         log(LOGC_NONE, LOGL_ERR,
 138                             "%s: spi read transfer failed (err: %d)\n",
 139                             __func__, ret);
 140                         goto release_bus;
 141                 }
 142
 143                 if (in) {
 144                         memcpy(in, rx_buf, transfer_len);
 145                         in += transfer_len;
 146                 }
 147
 148                 len -= transfer_len;
 149         }
 150
 151 release_bus:
 152         /* If an error occurred, release the chip by deasserting the CS */
 153         if (ret < 0)
 154                 spi_xfer(slave, 0, NULL, NULL, SPI_XFER_END);
 155
 156         spi_release_bus(slave);
 157
 158         return ret;
 159 }
 160
 161 static int tpm_tis_spi_read(struct udevice *dev, u32 addr, u16 len, u8 *in)
 162 {
 163         return tpm_tis_spi_xfer(dev, addr, NULL, in, len);
 164 }
 165
 166 static int tpm_tis_spi_read32(struct udevice *dev, u32 addr, u32 *result)
 167 {
 168         __le32 result_le;
 169         int ret;
 170
 171         ret = tpm_tis_spi_read(dev, addr, sizeof(u32), (u8 *)&result_le);
 172         if (!ret)
 173                 *result = le32_to_cpu(result_le);
 174
 175         return ret;
 176 }
 177
 178 static int tpm_tis_spi_write(struct udevice *dev, u32 addr, u16 len, const u8 *out)
 179 {
 180         return tpm_tis_spi_xfer(dev, addr, out, NULL, len);
 181 }
 182
 183 static int tpm_tis_spi_write32(struct udevice *dev, u32 addr, u32 value)
 184 {
 185         __le32 value_le = cpu_to_le32(value);
 186
 187         return tpm_tis_spi_write(dev, addr, sizeof(value), (u8 *)&value_le);
 188 }
 189
 190 static struct tpm_tis_phy_ops phy_ops = {
 191         .read_bytes = tpm_tis_spi_read,
 192         .write_bytes = tpm_tis_spi_write,
 193         .read32 = tpm_tis_spi_read32,
 194         .write32 = tpm_tis_spi_write32,
 195 };
 196
 197 static int tpm_tis_spi_probe(struct udevice *dev)
 198 {
 199         struct tpm_tis_chip_data *drv_data = (void *)dev_get_driver_data(dev);
 200         struct tpm_chip_priv *priv = dev_get_uclass_priv(dev);
 201         int ret;
 202
 203         /* Use the TPM v2 stack */
 204         priv->version = TPM_V2;
 205
 206         if (CONFIG_IS_ENABLED(DM_GPIO)) {
 207                 struct gpio_desc reset_gpio;
 208
 209                 ret = gpio_request_by_name(dev, "reset-gpios", 0,
 210                                            &reset_gpio, GPIOD_IS_OUT);
 211                 if (ret) {
 212                         /* legacy reset */
 213                         ret = gpio_request_by_name(dev, "gpio-reset", 0,
 214                                                    &reset_gpio, GPIOD_IS_OUT);
 215                         if (!ret) {
 216                                 log(LOGC_NONE, LOGL_NOTICE,
 217                                     "%s: gpio-reset is deprecated\n", __func__);
 218                         }
 219                 }
 220
 221                 if (!ret) {
 222                         log(LOGC_NONE, LOGL_WARNING,
 223                             "%s: TPM gpio reset should not be used on secure production devices\n",
 224                             dev->name);
 225                         dm_gpio_set_value(&reset_gpio, 1);
 226                         mdelay(1);
 227                         dm_gpio_set_value(&reset_gpio, 0);
 228                 }
 229         }
 230
 231         /* Ensure a minimum amount of time elapsed since reset of the TPM */
 232         mdelay(drv_data->time_before_first_cmd_ms);
 233
 234         tpm_tis_ops_register(dev, &phy_ops);
 235         ret = tpm_tis_init(dev);
 236         if (ret)
 237                 goto err;
 238
 239         priv->pcr_count = drv_data->pcr_count;
 240         priv->pcr_select_min = drv_data->pcr_select_min;
 241         priv->version = TPM_V2;
 242
 243         return 0;
 244 err:
 245         return -EINVAL;
 246 }
 247
 248 static int tpm_tis_spi_remove(struct udevice *udev)
 249 {
 250         return tpm_tis_cleanup(udev);
 251 }
 252
 253 static const struct tpm_ops tpm_tis_spi_ops = {
 254         .open           = tpm_tis_open,
 255         .close          = tpm_tis_close,
 256         .get_desc       = tpm_tis_get_desc,
 257         .send           = tpm_tis_send,
 258         .recv           = tpm_tis_recv,
 259         .cleanup        = tpm_tis_cleanup,
 260 };
 261
 262 static const struct tpm_tis_chip_data tpm_tis_std_chip_data = {
 263         .pcr_count = 24,
 264         .pcr_select_min = 3,
 265         .time_before_first_cmd_ms = 30,
 266 };
 267
 268 static const struct udevice_id tpm_tis_spi_ids[] = {
 269         {
 270                 .compatible = "tcg,tpm_tis-spi",
 271                 .data = (ulong)&tpm_tis_std_chip_data,
 272         },
 273         { }
 274 };
 275
 276 U_BOOT_DRIVER(tpm_tis_spi) = {
 277         .name   = "tpm_tis_spi",
 278         .id     = UCLASS_TPM,
 279         .of_match = tpm_tis_spi_ids,
 280         .ops    = &tpm_tis_spi_ops,
 281         .probe  = tpm_tis_spi_probe,
 282         .remove = tpm_tis_spi_remove,
 283         .priv_auto      = sizeof(struct tpm_chip),
 284 };