drivers/char/tpm/tpm_tis_spi_main.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/acpi.h>
  24 #include <linux/completion.h>
  25 #include <linux/init.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/slab.h>
  30
  31 #include <linux/of_device.h>
  32 #include <linux/spi/spi.h>
  33 #include <linux/tpm.h>
  34
  35 #include "tpm.h"
  36 #include "tpm_tis_core.h"
  37 #include "tpm_tis_spi.h"
  38
  39 #define MAX_SPI_FRAMESIZE 64
  40
  41 /*
  42  * TCG SPI flow control is documented in section 6.4 of the spec[1]. In short,
  43  * keep trying to read from the device until MISO goes high indicating the
  44  * wait state has ended.
  45  *
  46  * [1] https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
  47  */
  48 static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy,
  49                                     struct spi_transfer *spi_xfer)
  50 {
  51         struct spi_message m;
  52         int ret, i;
  53
  54         if ((phy->iobuf[3] & 0x01) == 0) {
  55                 // handle SPI wait states
  56                 for (i = 0; i < TPM_RETRY; i++) {
  57                         spi_xfer->len = 1;
  58                         spi_message_init(&m);
  59                         spi_message_add_tail(spi_xfer, &m);
  60                         ret = spi_sync_locked(phy->spi_device, &m);
  61                         if (ret < 0)
  62                                 return ret;
  63                         if (phy->iobuf[0] & 0x01)
  64                                 break;
  65                 }
  66
  67                 if (i == TPM_RETRY)
  68                         return -ETIMEDOUT;
  69         }
  70
  71         return 0;
  72 }
  73
  74 int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
  75                          u8 *in, const u8 *out)
  76 {
  77         struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
  78         int ret = 0;
  79         struct spi_message m;
  80         struct spi_transfer spi_xfer;
  81         u8 transfer_len;
  82
  83         spi_bus_lock(phy->spi_device->master);
  84
  85         while (len) {
  86                 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
  87
  88                 phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
  89                 phy->iobuf[1] = 0xd4;
  90                 phy->iobuf[2] = addr >> 8;
  91                 phy->iobuf[3] = addr;
  92
  93                 memset(&spi_xfer, 0, sizeof(spi_xfer));
  94                 spi_xfer.tx_buf = phy->iobuf;
  95                 spi_xfer.rx_buf = phy->iobuf;
  96                 spi_xfer.len = 4;
  97                 spi_xfer.cs_change = 1;
  98
  99                 spi_message_init(&m);
 100                 spi_message_add_tail(&spi_xfer, &m);
 101                 ret = spi_sync_locked(phy->spi_device, &m);
 102                 if (ret < 0)
 103                         goto exit;
 104
 105                 /* Flow control transfers are receive only */
 106                 spi_xfer.tx_buf = NULL;
 107                 ret = phy->flow_control(phy, &spi_xfer);
 108                 if (ret < 0)
 109                         goto exit;
 110
 111                 spi_xfer.cs_change = 0;
 112                 spi_xfer.len = transfer_len;
 113                 spi_xfer.delay.value = 5;
 114                 spi_xfer.delay.unit = SPI_DELAY_UNIT_USECS;
 115
 116                 if (out) {
 117                         spi_xfer.tx_buf = phy->iobuf;
 118                         spi_xfer.rx_buf = NULL;
 119                         memcpy(phy->iobuf, out, transfer_len);
 120                         out += transfer_len;
 121                 }
 122
 123                 spi_message_init(&m);
 124                 spi_message_add_tail(&spi_xfer, &m);
 125                 reinit_completion(&phy->ready);
 126                 ret = spi_sync_locked(phy->spi_device, &m);
 127                 if (ret < 0)
 128                         goto exit;
 129
 130                 if (in) {
 131                         memcpy(in, phy->iobuf, transfer_len);
 132                         in += transfer_len;
 133                 }
 134
 135                 len -= transfer_len;
 136         }
 137
 138 exit:
 139         spi_bus_unlock(phy->spi_device->master);
 140         return ret;
 141 }
 142
 143 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
 144                                   u16 len, u8 *result)
 145 {
 146         return tpm_tis_spi_transfer(data, addr, len, result, NULL);
 147 }
 148
 149 static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
 150                                    u16 len, const u8 *value)
 151 {
 152         return tpm_tis_spi_transfer(data, addr, len, NULL, value);
 153 }
 154
 155 int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
 156 {
 157         __le16 result_le;
 158         int rc;
 159
 160         rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
 161                                        (u8 *)&result_le);
 162         if (!rc)
 163                 *result = le16_to_cpu(result_le);
 164
 165         return rc;
 166 }
 167
 168 int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
 169 {
 170         __le32 result_le;
 171         int rc;
 172
 173         rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
 174                                        (u8 *)&result_le);
 175         if (!rc)
 176                 *result = le32_to_cpu(result_le);
 177
 178         return rc;
 179 }
 180
 181 int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
 182 {
 183         __le32 value_le;
 184         int rc;
 185
 186         value_le = cpu_to_le32(value);
 187         rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
 188                                         (u8 *)&value_le);
 189
 190         return rc;
 191 }
 192
 193 int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
 194                      int irq, const struct tpm_tis_phy_ops *phy_ops)
 195 {
 196         phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
 197         if (!phy->iobuf)
 198                 return -ENOMEM;
 199
 200         phy->spi_device = spi;
 201
 202         return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL);
 203 }
 204
 205 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
 206         .read_bytes = tpm_tis_spi_read_bytes,
 207         .write_bytes = tpm_tis_spi_write_bytes,
 208         .read16 = tpm_tis_spi_read16,
 209         .read32 = tpm_tis_spi_read32,
 210         .write32 = tpm_tis_spi_write32,
 211 };
 212
 213 static int tpm_tis_spi_probe(struct spi_device *dev)
 214 {
 215         struct tpm_tis_spi_phy *phy;
 216         int irq;
 217
 218         phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
 219                            GFP_KERNEL);
 220         if (!phy)
 221                 return -ENOMEM;
 222
 223         phy->flow_control = tpm_tis_spi_flow_control;
 224
 225         /* If the SPI device has an IRQ then use that */
 226         if (dev->irq > 0)
 227                 irq = dev->irq;
 228         else
 229                 irq = -1;
 230
 231         init_completion(&phy->ready);
 232         return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops);
 233 }
 234
 235 typedef int (*tpm_tis_spi_probe_func)(struct spi_device *);
 236
 237 static int tpm_tis_spi_driver_probe(struct spi_device *spi)
 238 {
 239         const struct spi_device_id *spi_dev_id = spi_get_device_id(spi);
 240         tpm_tis_spi_probe_func probe_func;
 241
 242         probe_func = of_device_get_match_data(&spi->dev);
 243         if (!probe_func) {
 244                 if (spi_dev_id) {
 245                         probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
 246                         if (!probe_func)
 247                                 return -ENODEV;
 248                 } else
 249                         probe_func = tpm_tis_spi_probe;
 250         }
 251
 252         return probe_func(spi);
 253 }
 254
 255 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume);
 256
 257 static int tpm_tis_spi_remove(struct spi_device *dev)
 258 {
 259         struct tpm_chip *chip = spi_get_drvdata(dev);
 260
 261         tpm_chip_unregister(chip);
 262         tpm_tis_remove(chip);
 263         return 0;
 264 }
 265
 266 static const struct spi_device_id tpm_tis_spi_id[] = {
 267         { "st33htpm-spi", (unsigned long)tpm_tis_spi_probe },
 268         { "slb9670", (unsigned long)tpm_tis_spi_probe },
 269         { "tpm_tis_spi", (unsigned long)tpm_tis_spi_probe },
 270         { "tpm_tis-spi", (unsigned long)tpm_tis_spi_probe },
 271         { "cr50", (unsigned long)cr50_spi_probe },
 272         {}
 273 };
 274 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
 275
 276 static const struct of_device_id of_tis_spi_match[] = {
 277         { .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe },
 278         { .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe },
 279         { .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe },
 280         { .compatible = "google,cr50", .data = cr50_spi_probe },
 281         {}
 282 };
 283 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
 284
 285 static const struct acpi_device_id acpi_tis_spi_match[] = {
 286         {"SMO0768", 0},
 287         {}
 288 };
 289 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
 290
 291 static struct spi_driver tpm_tis_spi_driver = {
 292         .driver = {
 293                 .name = "tpm_tis_spi",
 294                 .pm = &tpm_tis_pm,
 295                 .of_match_table = of_match_ptr(of_tis_spi_match),
 296                 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
 297                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
 298         },
 299         .probe = tpm_tis_spi_driver_probe,
 300         .remove = tpm_tis_spi_remove,
 301         .id_table = tpm_tis_spi_id,
 302 };
 303 module_spi_driver(tpm_tis_spi_driver);
 304
 305 MODULE_DESCRIPTION("TPM Driver for native SPI access");
 306 MODULE_LICENSE("GPL");