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 <peter.huewe@infineon.com>
   8  * Christophe Ricard <christophe-h.ricard@st.com>
   9  *
  10  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  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                 phy->iobuf[0] = 0;
  57
  58                 for (i = 0; i < TPM_RETRY; i++) {
  59                         spi_xfer->len = 1;
  60                         spi_message_init(&m);
  61                         spi_message_add_tail(spi_xfer, &m);
  62                         ret = spi_sync_locked(phy->spi_device, &m);
  63                         if (ret < 0)
  64                                 return ret;
  65                         if (phy->iobuf[0] & 0x01)
  66                                 break;
  67                 }
  68
  69                 if (i == TPM_RETRY)
  70                         return -ETIMEDOUT;
  71         }
  72
  73         return 0;
  74 }
  75
  76 int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
  77                          u8 *in, const u8 *out)
  78 {
  79         struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
  80         int ret = 0;
  81         struct spi_message m;
  82         struct spi_transfer spi_xfer;
  83         u8 transfer_len;
  84
  85         spi_bus_lock(phy->spi_device->master);
  86
  87         while (len) {
  88                 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
  89
  90                 phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
  91                 phy->iobuf[1] = 0xd4;
  92                 phy->iobuf[2] = addr >> 8;
  93                 phy->iobuf[3] = addr;
  94
  95                 memset(&spi_xfer, 0, sizeof(spi_xfer));
  96                 spi_xfer.tx_buf = phy->iobuf;
  97                 spi_xfer.rx_buf = phy->iobuf;
  98                 spi_xfer.len = 4;
  99                 spi_xfer.cs_change = 1;
 100
 101                 spi_message_init(&m);
 102                 spi_message_add_tail(&spi_xfer, &m);
 103                 ret = spi_sync_locked(phy->spi_device, &m);
 104                 if (ret < 0)
 105                         goto exit;
 106
 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 (in) {
 117                         spi_xfer.tx_buf = NULL;
 118                 } else if (out) {
 119                         spi_xfer.rx_buf = NULL;
 120                         memcpy(phy->iobuf, out, transfer_len);
 121                         out += transfer_len;
 122                 }
 123
 124                 spi_message_init(&m);
 125                 spi_message_add_tail(&spi_xfer, &m);
 126                 reinit_completion(&phy->ready);
 127                 ret = spi_sync_locked(phy->spi_device, &m);
 128                 if (ret < 0)
 129                         goto exit;
 130
 131                 if (in) {
 132                         memcpy(in, phy->iobuf, transfer_len);
 133                         in += transfer_len;
 134                 }
 135
 136                 len -= transfer_len;
 137         }
 138
 139 exit:
 140         spi_bus_unlock(phy->spi_device->master);
 141         return ret;
 142 }
 143
 144 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
 145                                   u16 len, u8 *result)
 146 {
 147         return tpm_tis_spi_transfer(data, addr, len, result, NULL);
 148 }
 149
 150 static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
 151                                    u16 len, const u8 *value)
 152 {
 153         return tpm_tis_spi_transfer(data, addr, len, NULL, value);
 154 }
 155
 156 int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
 157 {
 158         __le16 result_le;
 159         int rc;
 160
 161         rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
 162                                        (u8 *)&result_le);
 163         if (!rc)
 164                 *result = le16_to_cpu(result_le);
 165
 166         return rc;
 167 }
 168
 169 int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
 170 {
 171         __le32 result_le;
 172         int rc;
 173
 174         rc = data->phy_ops->read_bytes(data, addr, sizeof(u32),
 175                                        (u8 *)&result_le);
 176         if (!rc)
 177                 *result = le32_to_cpu(result_le);
 178
 179         return rc;
 180 }
 181
 182 int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
 183 {
 184         __le32 value_le;
 185         int rc;
 186
 187         value_le = cpu_to_le32(value);
 188         rc = data->phy_ops->write_bytes(data, addr, sizeof(u32),
 189                                         (u8 *)&value_le);
 190
 191         return rc;
 192 }
 193
 194 int tpm_tis_spi_init(struct spi_device *spi, struct tpm_tis_spi_phy *phy,
 195                      int irq, const struct tpm_tis_phy_ops *phy_ops)
 196 {
 197         phy->iobuf = devm_kmalloc(&spi->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
 198         if (!phy->iobuf)
 199                 return -ENOMEM;
 200
 201         phy->spi_device = spi;
 202
 203         return tpm_tis_core_init(&spi->dev, &phy->priv, irq, phy_ops, NULL);
 204 }
 205
 206 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
 207         .read_bytes = tpm_tis_spi_read_bytes,
 208         .write_bytes = tpm_tis_spi_write_bytes,
 209         .read16 = tpm_tis_spi_read16,
 210         .read32 = tpm_tis_spi_read32,
 211         .write32 = tpm_tis_spi_write32,
 212 };
 213
 214 static int tpm_tis_spi_probe(struct spi_device *dev)
 215 {
 216         struct tpm_tis_spi_phy *phy;
 217         int irq;
 218
 219         phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
 220                            GFP_KERNEL);
 221         if (!phy)
 222                 return -ENOMEM;
 223
 224         phy->flow_control = tpm_tis_spi_flow_control;
 225
 226         /* If the SPI device has an IRQ then use that */
 227         if (dev->irq > 0)
 228                 irq = dev->irq;
 229         else
 230                 irq = -1;
 231
 232         init_completion(&phy->ready);
 233         return tpm_tis_spi_init(dev, phy, irq, &tpm_spi_phy_ops);
 234 }
 235
 236 typedef int (*tpm_tis_spi_probe_func)(struct spi_device *);
 237
 238 static int tpm_tis_spi_driver_probe(struct spi_device *spi)
 239 {
 240         const struct spi_device_id *spi_dev_id = spi_get_device_id(spi);
 241         tpm_tis_spi_probe_func probe_func;
 242
 243         probe_func = of_device_get_match_data(&spi->dev);
 244         if (!probe_func && spi_dev_id)
 245                 probe_func = (tpm_tis_spi_probe_func)spi_dev_id->driver_data;
 246         if (!probe_func)
 247                 return -ENODEV;
 248
 249         return probe_func(spi);
 250 }
 251
 252 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_spi_resume);
 253
 254 static int tpm_tis_spi_remove(struct spi_device *dev)
 255 {
 256         struct tpm_chip *chip = spi_get_drvdata(dev);
 257
 258         tpm_chip_unregister(chip);
 259         tpm_tis_remove(chip);
 260         return 0;
 261 }
 262
 263 static const struct spi_device_id tpm_tis_spi_id[] = {
 264         { "tpm_tis_spi", (unsigned long)tpm_tis_spi_probe },
 265         { "cr50", (unsigned long)cr50_spi_probe },
 266         {}
 267 };
 268 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
 269
 270 static const struct of_device_id of_tis_spi_match[] = {
 271         { .compatible = "st,st33htpm-spi", .data = tpm_tis_spi_probe },
 272         { .compatible = "infineon,slb9670", .data = tpm_tis_spi_probe },
 273         { .compatible = "tcg,tpm_tis-spi", .data = tpm_tis_spi_probe },
 274         { .compatible = "google,cr50", .data = cr50_spi_probe },
 275         {}
 276 };
 277 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
 278
 279 static const struct acpi_device_id acpi_tis_spi_match[] = {
 280         {"SMO0768", 0},
 281         {}
 282 };
 283 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
 284
 285 static struct spi_driver tpm_tis_spi_driver = {
 286         .driver = {
 287                 .name = "tpm_tis_spi",
 288                 .pm = &tpm_tis_pm,
 289                 .of_match_table = of_match_ptr(of_tis_spi_match),
 290                 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
 291         },
 292         .probe = tpm_tis_spi_driver_probe,
 293         .remove = tpm_tis_spi_remove,
 294         .id_table = tpm_tis_spi_id,
 295 };
 296 module_spi_driver(tpm_tis_spi_driver);
 297
 298 MODULE_DESCRIPTION("TPM Driver for native SPI access");
 299 MODULE_LICENSE("GPL");