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
  51         u8 tx_buf[MAX_SPI_FRAMESIZE + 4];
  52         u8 rx_buf[MAX_SPI_FRAMESIZE + 4];
  53 };
  54
  55 static inline struct tpm_tis_spi_phy *to_tpm_tis_spi_phy(struct tpm_tis_data *data)
  56 {
  57         return container_of(data, struct tpm_tis_spi_phy, priv);
  58 }
  59
  60 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
  61                                   u16 len, u8 *result)
  62 {
  63         struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
  64         int ret, i;
  65         struct spi_message m;
  66         struct spi_transfer spi_xfer = {
  67                 .tx_buf = phy->tx_buf,
  68                 .rx_buf = phy->rx_buf,
  69                 .len = 4,
  70         };
  71
  72         if (len > MAX_SPI_FRAMESIZE)
  73                 return -ENOMEM;
  74
  75         phy->tx_buf[0] = 0x80 | (len - 1);
  76         phy->tx_buf[1] = 0xd4;
  77         phy->tx_buf[2] = (addr >> 8)  & 0xFF;
  78         phy->tx_buf[3] = addr         & 0xFF;
  79
  80         spi_xfer.cs_change = 1;
  81         spi_message_init(&m);
  82         spi_message_add_tail(&spi_xfer, &m);
  83
  84         spi_bus_lock(phy->spi_device->master);
  85         ret = spi_sync_locked(phy->spi_device, &m);
  86         if (ret < 0)
  87                 goto exit;
  88
  89         memset(phy->tx_buf, 0, len);
  90
  91         /* According to TCG PTP specification, if there is no TPM present at
  92          * all, then the design has a weak pull-up on MISO. If a TPM is not
  93          * present, a pull-up on MISO means that the SB controller sees a 1,
  94          * and will latch in 0xFF on the read.
  95          */
  96         for (i = 0; (phy->rx_buf[0] & 0x01) == 0 && i < TPM_RETRY; i++) {
  97                 spi_xfer.len = 1;
  98                 spi_message_init(&m);
  99                 spi_message_add_tail(&spi_xfer, &m);
 100                 ret = spi_sync_locked(phy->spi_device, &m);
 101                 if (ret < 0)
 102                         goto exit;
 103         }
 104
 105         spi_xfer.cs_change = 0;
 106         spi_xfer.len = len;
 107         spi_xfer.rx_buf = result;
 108
 109         spi_message_init(&m);
 110         spi_message_add_tail(&spi_xfer, &m);
 111         ret = spi_sync_locked(phy->spi_device, &m);
 112
 113 exit:
 114         spi_bus_unlock(phy->spi_device->master);
 115         return ret;
 116 }
 117
 118 static int tpm_tis_spi_write_bytes(struct tpm_tis_data *data, u32 addr,
 119                                    u16 len, u8 *value)
 120 {
 121         struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
 122         int ret, i;
 123         struct spi_message m;
 124         struct spi_transfer spi_xfer = {
 125                 .tx_buf = phy->tx_buf,
 126                 .rx_buf = phy->rx_buf,
 127                 .len = 4,
 128         };
 129
 130         if (len > MAX_SPI_FRAMESIZE)
 131                 return -ENOMEM;
 132
 133         phy->tx_buf[0] = len - 1;
 134         phy->tx_buf[1] = 0xd4;
 135         phy->tx_buf[2] = (addr >> 8)  & 0xFF;
 136         phy->tx_buf[3] = addr         & 0xFF;
 137
 138         spi_xfer.cs_change = 1;
 139         spi_message_init(&m);
 140         spi_message_add_tail(&spi_xfer, &m);
 141
 142         spi_bus_lock(phy->spi_device->master);
 143         ret = spi_sync_locked(phy->spi_device, &m);
 144         if (ret < 0)
 145                 goto exit;
 146
 147         memset(phy->tx_buf, 0, len);
 148
 149         /* According to TCG PTP specification, if there is no TPM present at
 150          * all, then the design has a weak pull-up on MISO. If a TPM is not
 151          * present, a pull-up on MISO means that the SB controller sees a 1,
 152          * and will latch in 0xFF on the read.
 153          */
 154         for (i = 0; (phy->rx_buf[0] & 0x01) == 0 && i < TPM_RETRY; i++) {
 155                 spi_xfer.len = 1;
 156                 spi_message_init(&m);
 157                 spi_message_add_tail(&spi_xfer, &m);
 158                 ret = spi_sync_locked(phy->spi_device, &m);
 159                 if (ret < 0)
 160                         goto exit;
 161         }
 162
 163         spi_xfer.len = len;
 164         spi_xfer.tx_buf = value;
 165         spi_xfer.cs_change = 0;
 166         spi_xfer.tx_buf = value;
 167         spi_message_init(&m);
 168         spi_message_add_tail(&spi_xfer, &m);
 169         ret = spi_sync_locked(phy->spi_device, &m);
 170
 171 exit:
 172         spi_bus_unlock(phy->spi_device->master);
 173         return ret;
 174 }
 175
 176 static int tpm_tis_spi_read16(struct tpm_tis_data *data, u32 addr, u16 *result)
 177 {
 178         int rc;
 179
 180         rc = data->phy_ops->read_bytes(data, addr, sizeof(u16), (u8 *)result);
 181         if (!rc)
 182                 *result = le16_to_cpu(*result);
 183         return rc;
 184 }
 185
 186 static int tpm_tis_spi_read32(struct tpm_tis_data *data, u32 addr, u32 *result)
 187 {
 188         int rc;
 189
 190         rc = data->phy_ops->read_bytes(data, addr, sizeof(u32), (u8 *)result);
 191         if (!rc)
 192                 *result = le32_to_cpu(*result);
 193         return rc;
 194 }
 195
 196 static int tpm_tis_spi_write32(struct tpm_tis_data *data, u32 addr, u32 value)
 197 {
 198         value = cpu_to_le32(value);
 199         return data->phy_ops->write_bytes(data, addr, sizeof(u32),
 200                                            (u8 *)&value);
 201 }
 202
 203 static const struct tpm_tis_phy_ops tpm_spi_phy_ops = {
 204         .read_bytes = tpm_tis_spi_read_bytes,
 205         .write_bytes = tpm_tis_spi_write_bytes,
 206         .read16 = tpm_tis_spi_read16,
 207         .read32 = tpm_tis_spi_read32,
 208         .write32 = tpm_tis_spi_write32,
 209 };
 210
 211 static int tpm_tis_spi_probe(struct spi_device *dev)
 212 {
 213         struct tpm_tis_spi_phy *phy;
 214
 215         phy = devm_kzalloc(&dev->dev, sizeof(struct tpm_tis_spi_phy),
 216                            GFP_KERNEL);
 217         if (!phy)
 218                 return -ENOMEM;
 219
 220         phy->spi_device = dev;
 221
 222         return tpm_tis_core_init(&dev->dev, &phy->priv, -1, &tpm_spi_phy_ops,
 223                                  NULL);
 224 }
 225
 226 static SIMPLE_DEV_PM_OPS(tpm_tis_pm, tpm_pm_suspend, tpm_tis_resume);
 227
 228 static int tpm_tis_spi_remove(struct spi_device *dev)
 229 {
 230         struct tpm_chip *chip = spi_get_drvdata(dev);
 231
 232         tpm_chip_unregister(chip);
 233         tpm_tis_remove(chip);
 234         return 0;
 235 }
 236
 237 static const struct spi_device_id tpm_tis_spi_id[] = {
 238         {"tpm_tis_spi", 0},
 239         {}
 240 };
 241 MODULE_DEVICE_TABLE(spi, tpm_tis_spi_id);
 242
 243 static const struct of_device_id of_tis_spi_match[] = {
 244         { .compatible = "st,st33htpm-spi", },
 245         { .compatible = "infineon,slb9670", },
 246         { .compatible = "tcg,tpm_tis-spi", },
 247         {}
 248 };
 249 MODULE_DEVICE_TABLE(of, of_tis_spi_match);
 250
 251 static const struct acpi_device_id acpi_tis_spi_match[] = {
 252         {"SMO0768", 0},
 253         {}
 254 };
 255 MODULE_DEVICE_TABLE(acpi, acpi_tis_spi_match);
 256
 257 static struct spi_driver tpm_tis_spi_driver = {
 258         .driver = {
 259                 .owner = THIS_MODULE,
 260                 .name = "tpm_tis_spi",
 261                 .pm = &tpm_tis_pm,
 262                 .of_match_table = of_match_ptr(of_tis_spi_match),
 263                 .acpi_match_table = ACPI_PTR(acpi_tis_spi_match),
 264         },
 265         .probe = tpm_tis_spi_probe,
 266         .remove = tpm_tis_spi_remove,
 267         .id_table = tpm_tis_spi_id,
 268 };
 269 module_spi_driver(tpm_tis_spi_driver);
 270
 271 MODULE_DESCRIPTION("TPM Driver for native SPI access");
 272 MODULE_LICENSE("GPL");