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/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         int rc;
 156
 157         rc = data->phy_ops->read_bytes(data, addr, sizeof(u16), (u8 *)result);
 158         if (!rc)
 159                 *result = le16_to_cpu(*result);
 160         return rc;
 161 }
 162
 163 static int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
 164 {
 165         int rc;
 166
 167         rc = data->phy_ops->read_bytes(data, addr, sizeof(u32), (u8 *)result);
 168         if (!rc)
 169                 *result = le32_to_cpu(*result);
 170         return rc;
 171 }
 172
 173 static int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
 174 {
 175         value = cpu_to_le32(value);
 176         return data->phy_ops->write_bytes(data, addr, sizeof(u32),
 177                                            (u8 *)&value);
 178 }
 179
 180 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
 181         .read_bytes = tpm_tis_spi_read_bytes,
 182         .write_bytes = tpm_tis_spi_write_bytes,
 183         .read16 = tpm_tis_spi_read16,
 184         .read32 = tpm_tis_spi_read32,
 185         .write32 = tpm_tis_spi_write32,
 186 };
 187
 188 static int tpm_tis_spi_probe(struct spi_device *dev)
 189 {
 190         struct tpm_tis_spi_phy *phy;
 191         int irq;
 192
 193         phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
 194                            GFP_KERNEL);
 195         if (!phy)
 196                 return -ENOMEM;
 197
 198         phy->spi_device = dev;
 199
 200         phy->iobuf = devm_kmalloc(&dev->dev, MAX_SPI_FRAMESIZE, GFP_KERNEL);
 201         if (!phy->iobuf)
 202                 return -ENOMEM;
 203
 204         /* If the SPI device has an IRQ then use that */
 205         if (dev->irq > 0)
 206                 irq = dev->irq;
 207         else
 208                 irq = -1;
 209
 210         return tpm_tis_core_init(&dev->dev, &phy->priv, irq, &tpm_spi_phy_ops,
 211                                  NULL);
 212 }
 213
 214 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
 215
 216 static int tpm_tis_spi_remove(struct spi_device *dev)
 217 {
 218         struct tpm_chip *chip = spi_get_drvdata(dev);
 219
 220         tpm_chip_unregister(chip);
 221         tpm_tis_remove(chip);
 222         return 0;
 223 }
 224
 225 static const struct spi_device_id tpm_tis_spi_id[] = {
 226         {"tpm_tis_spi", 0},
 227         {}
 228 };
 229 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
 230
 231 static const struct of_device_id of_tis_spi_match[] = {
 232         { .compatible = "st,st33htpm-spi", },
 233         { .compatible = "infineon,slb9670", },
 234         { .compatible = "tcg,tpm_tis-spi", },
 235         {}
 236 };
 237 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
 238
 239 static const struct acpi_device_id acpi_tis_spi_match[] = {
 240         {"SMO0768", 0},
 241         {}
 242 };
 243 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
 244
 245 static struct spi_driver tpm_tis_spi_driver = {
 246         .driver = {
 247                 .owner = THIS_MODULE,
 248                 .name = "tpm_tis_spi",
 249                 .pm = &tpm_tis_pm,
 250                 .of_match_table = of_match_ptr(of_tis_spi_match),
 251                 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
 252         },
 253         .probe = tpm_tis_spi_probe,
 254         .remove = tpm_tis_spi_remove,
 255         .id_table = tpm_tis_spi_id,
 256 };
 257 module_spi_driver(tpm_tis_spi_driver);
 258
 259 MODULE_DESCRIPTION("TPM Driver for native SPI access");
 260 MODULE_LICENSE("GPL");