drivers/char/tpm/tpm_tis_spi.c

   1 /*
   2  * Copyright (C) 2015 Infineon Technologies AG
   3  * Copyright (C) 2016 STMicroelectronics SAS
   4  *
   5  * Authors:
   6  * Peter Huewe <[email protected]>
   7  * Christophe Ricard <[email protected]>
   8  *
   9  * Maintained by: <[email protected]>
  10  *
  11  * Device driver for TCG/TCPA TPM (trusted platform module).
  12  * Specifications at www.trustedcomputinggroup.org
  13  *
  14  * This device driver implements the TPM interface as defined in
  15  * the TCG TPM Interface Spec version 1.3, revision 27 via _raw/native
  16  * SPI access_.
  17  *
  18  * It is based on the original tpm_tis device driver from Leendert van
  19  * Dorn and Kyleen Hall and Jarko Sakkinnen.
  20  *
  21  * This program is free software; you can redistribute it and/or
  22  * modify it under the terms of the GNU General Public License as
  23  * published by the Free Software Foundation, version 2 of the
  24  * License.
  25  */
  26
  27 #include <linux/init.h>
  28 #include <linux/module.h>
  29 #include <linux/moduleparam.h>
  30 #include <linux/slab.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/wait.h>
  33 #include <linux/acpi.h>
  34 #include <linux/freezer.h>
  35
  36 #include <linux/spi/spi.h>
  37 #include <linux/gpio.h>
  38 #include <linux/of_irq.h>
  39 #include <linux/of_gpio.h>
  40 #include <linux/tpm.h>
  41 #include "tpm.h"
  42 #include "tpm_tis_core.h"
  43
  44 #define MAX_SPI_FRAMESIZE 64
  45
  46 struct tpm_tis_spi_phy {
  47         struct tpm_tis_data priv;
  48         struct spi_device *spi_device;
  49         u8 *iobuf;
  50 };
  51
  52 static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
  53 {
  54         return container_of(data, struct tpm_tis_spi_phy, priv);
  55 }
  56
  57 static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
  58                                 u8 *in, const u8 *out)
  59 {
  60         struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
  61         int ret = 0;
  62         int i;
  63         struct spi_message m;
  64         struct spi_transfer spi_xfer;
  65         u8 transfer_len;
  66
  67         spi_bus_lock(phy->spi_device->master);
  68
  69         while (len) {
  70                 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
  71
  72                 phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
  73                 phy->iobuf[1] = 0xd4;
  74                 phy->iobuf[2] = addr >> 8;
  75                 phy->iobuf[3] = addr;
  76
  77                 memset(&spi_xfer, 0, sizeof(spi_xfer));
  78                 spi_xfer.tx_buf = phy->iobuf;
  79                 spi_xfer.rx_buf = phy->iobuf;
  80                 spi_xfer.len = 4;
  81                 spi_xfer.cs_change = 1;
  82
  83                 spi_message_init(&m);
  84                 spi_message_add_tail(&spi_xfer, &m);
  85                 ret = spi_sync_locked(phy->spi_device, &m);
  86                 if (ret < 0)
  87                         goto exit;
  88
  89                 if ((phy->iobuf[3] & 0x01) == 0) {
  90                         // handle SPI wait states
  91                         phy->iobuf[0] = 0;
  92
  93                         for (i = 0; i < TPM_RETRY; i++) {
  94                                 spi_xfer.len = 1;
  95                                 spi_message_init(&m);
  96                                 spi_message_add_tail(&spi_xfer, &m);
  97                                 ret = spi_sync_locked(phy->spi_device, &m);
  98                                 if (ret < 0)
  99                                         goto exit;
 100                                 if (phy->iobuf[0] & 0x01)
 101                                         break;
 102                         }
 103
 104                         if (i == TPM_RETRY) {
 105                                 ret = -ETIMEDOUT;
 106                                 goto exit;
 107                         }
 108                 }
 109
 110                 spi_xfer.cs_change = 0;
 111                 spi_xfer.len = transfer_len;
 112                 spi_xfer.delay_usecs = 5;
 113
 114                 if (in) {
 115                         spi_xfer.tx_buf = NULL;
 116                 } else if (out) {
 117                         spi_xfer.rx_buf = NULL;
 118                         memcpy(phy->iobuf, out, transfer_len);
 119                         out += transfer_len;
 120                 }
 121
 122                 spi_message_init(&m);
 123                 spi_message_add_tail(&spi_xfer, &m);
 124                 ret = spi_sync_locked(phy->spi_device, &m);
 125                 if (ret < 0)
 126                         goto exit;
 127
 128                 if (in) {
 129                         memcpy(in, phy->iobuf, transfer_len);
 130                         in += transfer_len;
 131                 }
 132
 133                 len -= transfer_len;
 134         }
 135
 136 exit:
 137         spi_bus_unlock(phy->spi_device->master);
 138         return ret;
 139 }
 140
 141 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
 142                                   u16 len, u8 *result)
 143 {
 144         return tpm_tis_spi_transfer(data, addr, len, result, NULL);
 145 }
 146
 147 static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
 148                                    u16 len, const u8 *value)
 149 {
 150         return tpm_tis_spi_transfer(data, addr, len, NULL, value);
 151 }
 152
 153 static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
 154 {
 155         __le16 result_le;
 156         int rc;
 157
 158         rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
 159                                        (u8 *)&result_le);
 160         if (!rc)
 161                 *result = le16_to_cpu(result_le);
 162
 163         return rc;
 164 }
 165
 166 static int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
 167 {
 168         __le32 result_le;
 169         int rc;
 170
 171         rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
 172                                        (u8 *)&result_le);
 173         if (!rc)
 174                 *result = le32_to_cpu(result_le);
 175
 176         return rc;
 177 }
 178
 179 static int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
 180 {
 181         __le32 value_le;
 182         int rc;
 183
 184         value_le = cpu_to_le32(value);
 185         rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
 186                                         (u8 *)&value_le);
 187
 188         return rc;
 189 }
 190
 191 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
 192         .read_bytes = tpm_tis_spi_read_bytes,
 193         .write_bytes = tpm_tis_spi_write_bytes,
 194         .read16 = tpm_tis_spi_read16,
 195         .read32 = tpm_tis_spi_read32,
 196         .write32 = tpm_tis_spi_write32,
 197 };
 198
 199 static int tpm_tis_spi_probe(struct spi_device *dev)
 200 {
 201         struct tpm_tis_spi_phy *phy;
 202         int irq;
 203
 204         phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
 205                            GFP_KERNEL);
 206         if (!phy)
 207                 return -ENOMEM;
 208
 209         phy->spi_device = dev;
 210
 211         phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
 212         if (!phy->iobuf)
 213                 return -ENOMEM;
 214
 215         /* If the SPI device has an IRQ then use that */
 216         if (dev->irq > 0)
 217                 irq = dev->irq;
 218         else
 219                 irq = -1;
 220
 221         return tpm_tis_core_init(&dev->dev, &phy->priv, irq, &tpm_spi_phy_ops,
 222                                  NULL);
 223 }
 224
 225 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
 226
 227 static int tpm_tis_spi_remove(struct spi_device *dev)
 228 {
 229         struct tpm_chip *chip = spi_get_drvdata(dev);
 230
 231         tpm_chip_unregister(chip);
 232         tpm_tis_remove(chip);
 233         return 0;
 234 }
 235
 236 static const struct spi_device_id tpm_tis_spi_id[] = {
 237         {"tpm_tis_spi", 0},
 238         {}
 239 };
 240 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
 241
 242 static const struct of_device_id of_tis_spi_match[] = {
 243         { .compatible = "st,st33htpm-spi", },
 244         { .compatible = "infineon,slb9670", },
 245         { .compatible = "tcg,tpm_tis-spi", },
 246         {}
 247 };
 248 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
 249
 250 static const struct acpi_device_id acpi_tis_spi_match[] = {
 251         {"SMO0768", 0},
 252         {}
 253 };
 254 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
 255
 256 static struct spi_driver tpm_tis_spi_driver = {
 257         .driver = {
 258                 .owner = THIS_MODULE,
 259                 .name = "tpm_tis_spi",
 260                 .pm = &tpm_tis_pm,
 261                 .of_match_table = of_match_ptr(of_tis_spi_match),
 262                 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
 263         },
 264         .probe = tpm_tis_spi_probe,
 265         .remove = tpm_tis_spi_remove,
 266         .id_table = tpm_tis_spi_id,
 267 };
 268 module_spi_driver(tpm_tis_spi_driver);
 269
 270 MODULE_DESCRIPTION("TPM Driver for native SPI access");
 271 MODULE_LICENSE("GPL");