drivers/char/tpm/tpm_tis_spi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2015 Infineon Technologies AG
   4  * Copyright (C) 2016 STMicroelectronics SAS
   5  *
   6  * Authors:
   7  * Peter Huewe <[email protected]>
   8  * Christophe Ricard <[email protected]>
   9  *
  10  * Maintained by: <[email protected]>
  11  *
  12  * Device driver for TCG/TCPA TPM (trusted platform module).
  13  * Specifications at www.trustedcomputinggroup.org
  14  *
  15  * This device driver implements the TPM interface as defined in
  16  * the TCG TPM Interface Spec version 1.3, revision 27 via _raw/native
  17  * SPI access_.
  18  *
  19  * It is based on the original tpm_tis device driver from Leendert van
  20  * Dorn and Kyleen Hall and Jarko Sakkinnen.
  21  */
  22
  23 #include <linux/init.h>
  24 #include <linux/module.h>
  25 #include <linux/moduleparam.h>
  26 #include <linux/slab.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/wait.h>
  29 #include <linux/acpi.h>
  30 #include <linux/freezer.h>
  31
  32 #include <linux/spi/spi.h>
  33 #include <linux/gpio.h>
  34 #include <linux/of_irq.h>
  35 #include <linux/of_gpio.h>
  36 #include <linux/tpm.h>
  37 #include "tpm.h"
  38 #include "tpm_tis_core.h"
  39
  40 #define MAX_SPI_FRAMESIZE 64
  41
  42 struct tpm_tis_spi_phy {
  43         struct tpm_tis_data priv;
  44         struct spi_device *spi_device;
  45         u8 *iobuf;
  46 };
  47
  48 static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
  49 {
  50         return container_of(data, struct tpm_tis_spi_phy, priv);
  51 }
  52
  53 static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
  54                                 u8 *in, const u8 *out)
  55 {
  56         struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
  57         int ret = 0;
  58         int i;
  59         struct spi_message m;
  60         struct spi_transfer spi_xfer;
  61         u8 transfer_len;
  62
  63         spi_bus_lock(phy->spi_device->master);
  64
  65         while (len) {
  66                 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
  67
  68                 phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
  69                 phy->iobuf[1] = 0xd4;
  70                 phy->iobuf[2] = addr >> 8;
  71                 phy->iobuf[3] = addr;
  72
  73                 memset(&spi_xfer, 0, sizeof(spi_xfer));
  74                 spi_xfer.tx_buf = phy->iobuf;
  75                 spi_xfer.rx_buf = phy->iobuf;
  76                 spi_xfer.len = 4;
  77                 spi_xfer.cs_change = 1;
  78
  79                 spi_message_init(&m);
  80                 spi_message_add_tail(&spi_xfer, &m);
  81                 ret = spi_sync_locked(phy->spi_device, &m);
  82                 if (ret < 0)
  83                         goto exit;
  84
  85                 if ((phy->iobuf[3] & 0x01) == 0) {
  86                         // handle SPI wait states
  87                         phy->iobuf[0] = 0;
  88
  89                         for (i = 0; i < TPM_RETRY; i++) {
  90                                 spi_xfer.len = 1;
  91                                 spi_message_init(&m);
  92                                 spi_message_add_tail(&spi_xfer, &m);
  93                                 ret = spi_sync_locked(phy->spi_device, &m);
  94                                 if (ret < 0)
  95                                         goto exit;
  96                                 if (phy->iobuf[0] & 0x01)
  97                                         break;
  98                         }
  99
 100                         if (i == TPM_RETRY) {
 101                                 ret = -ETIMEDOUT;
 102                                 goto exit;
 103                         }
 104                 }
 105
 106                 spi_xfer.cs_change = 0;
 107                 spi_xfer.len = transfer_len;
 108                 spi_xfer.delay_usecs = 5;
 109
 110                 if (in) {
 111                         spi_xfer.tx_buf = NULL;
 112                 } else if (out) {
 113                         spi_xfer.rx_buf = NULL;
 114                         memcpy(phy->iobuf, out, transfer_len);
 115                         out += transfer_len;
 116                 }
 117
 118                 spi_message_init(&m);
 119                 spi_message_add_tail(&spi_xfer, &m);
 120                 ret = spi_sync_locked(phy->spi_device, &m);
 121                 if (ret < 0)
 122                         goto exit;
 123
 124                 if (in) {
 125                         memcpy(in, phy->iobuf, transfer_len);
 126                         in += transfer_len;
 127                 }
 128
 129                 len -= transfer_len;
 130         }
 131
 132 exit:
 133         spi_bus_unlock(phy->spi_device->master);
 134         return ret;
 135 }
 136
 137 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
 138                                   u16 len, u8 *result)
 139 {
 140         return tpm_tis_spi_transfer(data, addr, len, result, NULL);
 141 }
 142
 143 static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
 144                                    u16 len, const u8 *value)
 145 {
 146         return tpm_tis_spi_transfer(data, addr, len, NULL, value);
 147 }
 148
 149 static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
 150 {
 151         __le16 result_le;
 152         int rc;
 153
 154         rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
 155                                        (u8 *)&result_le);
 156         if (!rc)
 157                 *result = le16_to_cpu(result_le);
 158
 159         return rc;
 160 }
 161
 162 static int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
 163 {
 164         __le32 result_le;
 165         int rc;
 166
 167         rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
 168                                        (u8 *)&result_le);
 169         if (!rc)
 170                 *result = le32_to_cpu(result_le);
 171
 172         return rc;
 173 }
 174
 175 static int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
 176 {
 177         __le32 value_le;
 178         int rc;
 179
 180         value_le = cpu_to_le32(value);
 181         rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
 182                                         (u8 *)&value_le);
 183
 184         return rc;
 185 }
 186
 187 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
 188         .read_bytes = tpm_tis_spi_read_bytes,
 189         .write_bytes = tpm_tis_spi_write_bytes,
 190         .read16 = tpm_tis_spi_read16,
 191         .read32 = tpm_tis_spi_read32,
 192         .write32 = tpm_tis_spi_write32,
 193 };
 194
 195 static int tpm_tis_spi_probe(struct spi_device *dev)
 196 {
 197         struct tpm_tis_spi_phy *phy;
 198         int irq;
 199
 200         phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
 201                            GFP_KERNEL);
 202         if (!phy)
 203                 return -ENOMEM;
 204
 205         phy->spi_device = dev;
 206
 207         phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
 208         if (!phy->iobuf)
 209                 return -ENOMEM;
 210
 211         /* If the SPI device has an IRQ then use that */
 212         if (dev->irq > 0)
 213                 irq = dev->irq;
 214         else
 215                 irq = -1;
 216
 217         return tpm_tis_core_init(&dev->dev, &phy->priv, irq, &tpm_spi_phy_ops,
 218                                  NULL);
 219 }
 220
 221 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
 222
 223 static int tpm_tis_spi_remove(struct spi_device *dev)
 224 {
 225         struct tpm_chip *chip = spi_get_drvdata(dev);
 226
 227         tpm_chip_unregister(chip);
 228         tpm_tis_remove(chip);
 229         return 0;
 230 }
 231
 232 static const struct spi_device_id tpm_tis_spi_id[] = {
 233         {"tpm_tis_spi", 0},
 234         {}
 235 };
 236 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
 237
 238 static const struct of_device_id of_tis_spi_match[] = {
 239         { .compatible = "st,st33htpm-spi", },
 240         { .compatible = "infineon,slb9670", },
 241         { .compatible = "tcg,tpm_tis-spi", },
 242         {}
 243 };
 244 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
 245
 246 static const struct acpi_device_id acpi_tis_spi_match[] = {
 247         {"SMO0768", 0},
 248         {}
 249 };
 250 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
 251
 252 static struct spi_driver tpm_tis_spi_driver = {
 253         .driver = {
 254                 .owner = THIS_MODULE,
 255                 .name = "tpm_tis_spi",
 256                 .pm = &tpm_tis_pm,
 257                 .of_match_table = of_match_ptr(of_tis_spi_match),
 258                 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
 259         },
 260         .probe = tpm_tis_spi_probe,
 261         .remove = tpm_tis_spi_remove,
 262         .id_table = tpm_tis_spi_id,
 263 };
 264 module_spi_driver(tpm_tis_spi_driver);
 265
 266 MODULE_DESCRIPTION("TPM Driver for native SPI access");
 267 MODULE_LICENSE("GPL");