drivers/tpm/tis_i2c.c

   1 /*
   2  * Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
   3  * Use of this source code is governed by a BSD-style license that can be
   4  * found in the LICENSE file.
   5  */
   6
   7 #include <config.h>
   8 #include <common.h>
   9 #include <fdtdec.h>
  10 #include <i2c.h>
  11 #include "slb9635_i2c/tpm.h"
  12
  13 DECLARE_GLOBAL_DATA_PTR;
  14
  15 /* TPM configuration */
  16 struct tpm {
  17         int i2c_bus;
  18         int slave_addr;
  19         char inited;
  20         int old_bus;
  21 } tpm;
  22
  23
  24 static int tpm_select(void)
  25 {
  26         int ret;
  27
  28         tpm.old_bus = i2c_get_bus_num();
  29         if (tpm.old_bus != tpm.i2c_bus) {
  30                 ret = i2c_set_bus_num(tpm.i2c_bus);
  31                 if (ret) {
  32                         debug("%s: Fail to set i2c bus %d\n", __func__,
  33                               tpm.i2c_bus);
  34                         return -1;
  35                 }
  36         }
  37         return 0;
  38 }
  39
  40 static int tpm_deselect(void)
  41 {
  42         int ret;
  43
  44         if (tpm.old_bus != i2c_get_bus_num()) {
  45                 ret = i2c_set_bus_num(tpm.old_bus);
  46                 if (ret) {
  47                         debug("%s: Fail to restore i2c bus %d\n",
  48                               __func__, tpm.old_bus);
  49                         return -1;
  50                 }
  51         }
  52         tpm.old_bus = -1;
  53         return 0;
  54 }
  55
  56 /**
  57  * Decode TPM configuration.
  58  *
  59  * @param dev   Returns a configuration of TPM device
  60  * @return 0 if ok, -1 on error
  61  */
  62 static int tpm_decode_config(struct tpm *dev)
  63 {
  64 #ifdef CONFIG_OF_CONTROL
  65         const void *blob = gd->fdt_blob;
  66         int node, parent;
  67         int i2c_bus;
  68
  69         node = fdtdec_next_compatible(blob, 0, COMPAT_INFINEON_SLB9635_TPM);
  70         if (node < 0) {
  71                 debug("%s: Node not found\n", __func__);
  72                 return -1;
  73         }
  74         parent = fdt_parent_offset(blob, node);
  75         if (parent < 0) {
  76                 debug("%s: Cannot find node parent\n", __func__);
  77                 return -1;
  78         }
  79         i2c_bus = i2c_get_bus_num_fdt(parent);
  80         if (i2c_bus < 0)
  81                 return -1;
  82         dev->i2c_bus = i2c_bus;
  83         dev->slave_addr = fdtdec_get_addr(blob, node, "reg");
  84 #else
  85         dev->i2c_bus = CONFIG_INFINEON_TPM_I2C_BUS;
  86         dev->slave_addr = CONFIG_INFINEON_TPM_I2C_ADDR;
  87 #endif
  88         return 0;
  89 }
  90
  91 int tis_init(void)
  92 {
  93         if (tpm.inited)
  94                 return 0;
  95
  96         if (tpm_decode_config(&tpm))
  97                 return -1;
  98
  99         if (tpm_select())
 100                 return -1;
 101
 102         /*
 103          * Probe TPM twice; the first probing might fail because TPM is asleep,
 104          * and the probing can wake up TPM.
 105          */
 106         if (i2c_probe(tpm.slave_addr) && i2c_probe(tpm.slave_addr)) {
 107                 debug("%s: fail to probe i2c addr 0x%x\n", __func__,
 108                       tpm.slave_addr);
 109                 return -1;
 110         }
 111
 112         tpm_deselect();
 113
 114         tpm.inited = 1;
 115
 116         return 0;
 117 }
 118
 119 int tis_open(void)
 120 {
 121         int rc;
 122
 123         if (!tpm.inited)
 124                 return -1;
 125
 126         if (tpm_select())
 127                 return -1;
 128
 129         rc = tpm_open(tpm.slave_addr);
 130
 131         tpm_deselect();
 132
 133         return rc;
 134 }
 135
 136 int tis_close(void)
 137 {
 138         if (!tpm.inited)
 139                 return -1;
 140
 141         if (tpm_select())
 142                 return -1;
 143
 144         tpm_close();
 145
 146         tpm_deselect();
 147
 148         return 0;
 149 }
 150
 151 int tis_sendrecv(const uint8_t *sendbuf, size_t sbuf_size,
 152                 uint8_t *recvbuf, size_t *rbuf_len)
 153 {
 154         int len;
 155         uint8_t buf[4096];
 156
 157         if (!tpm.inited)
 158                 return -1;
 159
 160         if (sizeof(buf) < sbuf_size)
 161                 return -1;
 162
 163         memcpy(buf, sendbuf, sbuf_size);
 164
 165         if (tpm_select())
 166                 return -1;
 167
 168         len = tpm_transmit(buf, sbuf_size);
 169
 170         tpm_deselect();
 171
 172         if (len < 10) {
 173                 *rbuf_len = 0;
 174                 return -1;
 175         }
 176
 177         memcpy(recvbuf, buf, len);
 178         *rbuf_len = len;
 179
 180         return 0;
 181 }