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 <peter.huewe@infineon.com>
   7  * Christophe Ricard <christophe-h.ricard@st.com>
   8  *
   9  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  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/module.h>
  37 #include <linux/spi/spi.h>
  38 #include <linux/gpio.h>
  39 #include <linux/of_irq.h>
  40 #include <linux/of_gpio.h>
  41 #include <linux/tpm.h>
  42 #include "tpm.h"
  43 #include "tpm_tis_core.h"
  44
  45 #define MAX_SPI_FRAMESIZE 64
  46
  47 struct tpm_tis_spi_phy {
  48         struct tpm_tis_data priv;
  49         struct spi_device *spi_device;
  50         u8 *iobuf;
  51 };
  52
  53 static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
  54 {
  55         return container_of(data, struct tpm_tis_spi_phy, priv);
  56 }
  57
  58 static int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
  59                                 u8 *in, const u8 *out)
  60 {
  61         struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
  62         int ret = 0;
  63         int i;
  64         struct spi_message m;
  65         struct spi_transfer spi_xfer;
  66         u8 transfer_len;
  67
  68         spi_bus_lock(phy->spi_device->master);
  69
  70         while (len) {
  71                 transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
  72
  73                 phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
  74                 phy->iobuf[1] = 0xd4;
  75                 phy->iobuf[2] = addr >> 8;
  76                 phy->iobuf[3] = addr;
  77
  78                 memset(&spi_xfer, 0, sizeof(spi_xfer));
  79                 spi_xfer.tx_buf = phy->iobuf;
  80                 spi_xfer.rx_buf = phy->iobuf;
  81                 spi_xfer.len = 4;
  82                 spi_xfer.cs_change = 1;
  83
  84                 spi_message_init(&m);
  85                 spi_message_add_tail(&spi_xfer, &m);
  86                 ret = spi_sync_locked(phy->spi_device, &m);
  87                 if (ret < 0)
  88                         goto exit;
  89
  90                 if ((phy->iobuf[3] & 0x01) == 0) {
  91                         // handle SPI wait states
  92                         phy->iobuf[0] = 0;
  93
  94                         for (i = 0; i < TPM_RETRY; i++) {
  95                                 spi_xfer.len = 1;
  96                                 spi_message_init(&m);
  97                                 spi_message_add_tail(&spi_xfer, &m);
  98                                 ret = spi_sync_locked(phy->spi_device, &m);
  99                                 if (ret < 0)
 100                                         goto exit;
 101                                 if (phy->iobuf[0] & 0x01)
 102                                         break;
 103                         }
 104
 105                         if (i == TPM_RETRY) {
 106                                 ret = -ETIMEDOUT;
 107                                 goto exit;
 108                         }
 109                 }
 110
 111                 spi_xfer.cs_change = 0;
 112                 spi_xfer.len = transfer_len;
 113                 spi_xfer.delay_usecs = 5;
 114
 115                 if (in) {
 116                         spi_xfer.tx_buf = NULL;
 117                 } else if (out) {
 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                 ret = spi_sync_locked(phy->spi_device, &m);
 126                 if (ret < 0)
 127                         goto exit;
 128
 129                 if (in) {
 130                         memcpy(in, phy->iobuf, transfer_len);
 131                         in += transfer_len;
 132                 }
 133
 134                 len -= transfer_len;
 135         }
 136
 137 exit:
 138         spi_bus_unlock(phy->spi_device->master);
 139         return ret;
 140 }
 141
 142 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
 143                                   u16 len, u8 *result)
 144 {
 145         return tpm_tis_spi_transfer(data, addr, len, result, NULL);
 146 }
 147
 148 static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
 149                                    u16 len, const u8 *value)
 150 {
 151         return tpm_tis_spi_transfer(data, addr, len, NULL, value);
 152 }
 153
 154 static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
 155 {
 156         int rc;
 157
 158         rc = data->phy_ops->read_bytes(data, addr, sizeof(u16), (u8 *)result);
 159         if (!rc)
 160                 *result = le16_to_cpu(*result);
 161         return rc;
 162 }
 163
 164 static int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
 165 {
 166         int rc;
 167
 168         rc = data->phy_ops->read_bytes(data, addr, sizeof(u32), (u8 *)result);
 169         if (!rc)
 170                 *result = le32_to_cpu(*result);
 171         return rc;
 172 }
 173
 174 static int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
 175 {
 176         value = cpu_to_le32(value);
 177         return data->phy_ops->write_bytes(data, addr, sizeof(u32),
 178                                            (u8 *)&value);
 179 }
 180
 181 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
 182         .read_bytes = tpm_tis_spi_read_bytes,
 183         .write_bytes = tpm_tis_spi_write_bytes,
 184         .read16 = tpm_tis_spi_read16,
 185         .read32 = tpm_tis_spi_read32,
 186         .write32 = tpm_tis_spi_write32,
 187 };
 188
 189 static int tpm_tis_spi_probe(struct spi_device *dev)
 190 {
 191         struct tpm_tis_spi_phy *phy;
 192         int irq;
 193
 194         phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
 195                            GFP_KERNEL);
 196         if (!phy)
 197                 return -ENOMEM;
 198
 199         phy->spi_device = dev;
 200
 201         phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
 202         if (!phy->iobuf)
 203                 return -ENOMEM;
 204
 205         /* If the SPI device has an IRQ then use that */
 206         if (dev->irq > 0)
 207                 irq = dev->irq;
 208         else
 209                 irq = -1;
 210
 211         return tpm_tis_core_init(&dev->dev, &phy->priv, irq, &tpm_spi_phy_ops,
 212                                  NULL);
 213 }
 214
 215 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
 216
 217 static int tpm_tis_spi_remove(struct spi_device *dev)
 218 {
 219         struct tpm_chip *chip = spi_get_drvdata(dev);
 220
 221         tpm_chip_unregister(chip);
 222         tpm_tis_remove(chip);
 223         return 0;
 224 }
 225
 226 static const struct spi_device_id tpm_tis_spi_id[] = {
 227         {"tpm_tis_spi", 0},
 228         {}
 229 };
 230 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
 231
 232 static const struct of_device_id of_tis_spi_match[] = {
 233         { .compatible = "st,st33htpm-spi", },
 234         { .compatible = "infineon,slb9670", },
 235         { .compatible = "tcg,tpm_tis-spi", },
 236         {}
 237 };
 238 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
 239
 240 static const struct acpi_device_id acpi_tis_spi_match[] = {
 241         {"SMO0768", 0},
 242         {}
 243 };
 244 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
 245
 246 static struct spi_driver tpm_tis_spi_driver = {
 247         .driver = {
 248                 .owner = THIS_MODULE,
 249                 .name = "tpm_tis_spi",
 250                 .pm = &tpm_tis_pm,
 251                 .of_match_table = of_match_ptr(of_tis_spi_match),
 252                 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
 253         },
 254         .probe = tpm_tis_spi_probe,
 255         .remove = tpm_tis_spi_remove,
 256         .id_table = tpm_tis_spi_id,
 257 };
 258 module_spi_driver(tpm_tis_spi_driver);
 259
 260 MODULE_DESCRIPTION("TPM Driver for native SPI access");
 261 MODULE_LICENSE("GPL");