drivers/tpm/tpm_atmel_twi.c

   1 /*
   2  * Copyright (C) 2013 Guntermann & Drunck, GmbH
   3  *
   4  * Written by Dirk Eibach <eibach@gdsys.de>
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <dm.h>
  11 #include <tpm.h>
  12 #include <i2c.h>
  13 #include <asm/unaligned.h>
  14
  15 #include "tpm_internal.h"
  16
  17 #define ATMEL_TPM_TIMEOUT_MS 5000 /* sufficient for anything but
  18                                      generating/exporting keys */
  19
  20 /*
  21  * tpm_atmel_twi_open()
  22  *
  23  * Requests access to locality 0 for the caller. After all commands have been
  24  * completed the caller is supposed to call tis_close().
  25  *
  26  * Returns 0 on success, -1 on failure.
  27  */
  28 static int tpm_atmel_twi_open(struct udevice *dev)
  29 {
  30         return 0;
  31 }
  32
  33 /*
  34  * tpm_atmel_twi_close()
  35  *
  36  * terminate the currect session with the TPM by releasing the locked
  37  * locality. Returns 0 on success of -1 on failure (in case lock
  38  * removal did not succeed).
  39  */
  40 static int tpm_atmel_twi_close(struct udevice *dev)
  41 {
  42         return 0;
  43 }
  44
  45 /*
  46  * tpm_atmel_twi_get_desc()
  47  *
  48  * @dev:        Device to check
  49  * @buf:        Buffer to put the string
  50  * @size:       Maximum size of buffer
  51  * @return length of string, or -ENOSPC it no space
  52  */
  53 static int tpm_atmel_twi_get_desc(struct udevice *dev, char *buf, int size)
  54 {
  55         return 0;
  56 }
  57
  58 /*
  59  * tpm_atmel_twi_xfer()
  60  *
  61  * Send the requested data to the TPM and then try to get its response
  62  *
  63  * @sendbuf - buffer of the data to send
  64  * @send_size size of the data to send
  65  * @recvbuf - memory to save the response to
  66  * @recv_len - pointer to the size of the response buffer
  67  *
  68  * Returns 0 on success (and places the number of response bytes at recv_len)
  69  * or -1 on failure.
  70  */
  71 static int tpm_atmel_twi_xfer(struct udevice *dev,
  72                               const uint8_t *sendbuf, size_t send_size,
  73                               uint8_t *recvbuf, size_t *recv_len)
  74 {
  75         int res;
  76         unsigned long start;
  77
  78 #ifdef DEBUG
  79         memset(recvbuf, 0xcc, *recv_len);
  80         printf("send to TPM (%d bytes, recv_len=%d):\n", send_size, *recv_len);
  81         print_buffer(0, (void *)sendbuf, 1, send_size, 0);
  82 #endif
  83
  84 #ifndef CONFIG_DM_I2C
  85         res = i2c_write(0x29, 0, 0, (uchar *)sendbuf, send_size);
  86 #else
  87         res = dm_i2c_write(dev, 0, sendbuf, send_size);
  88 #endif
  89         if (res) {
  90                 printf("i2c_write returned %d\n", res);
  91                 return -1;
  92         }
  93
  94         start = get_timer(0);
  95 #ifndef CONFIG_DM_I2C
  96         while ((res = i2c_read(0x29, 0, 0, recvbuf, 10)))
  97 #else
  98         while ((res = dm_i2c_read(dev, 0, recvbuf, 10)))
  99 #endif
 100         {
 101                 /* TODO Use TIS_TIMEOUT from tpm_tis_infineon.h */
 102                 if (get_timer(start) > ATMEL_TPM_TIMEOUT_MS) {
 103                         puts("tpm timed out\n");
 104                         return -1;
 105                 }
 106                 udelay(100);
 107         }
 108         if (!res) {
 109                 *recv_len = get_unaligned_be32(recvbuf + 2);
 110                 if (*recv_len > 10)
 111 #ifndef CONFIG_DM_I2C
 112                         res = i2c_read(0x29, 0, 0, recvbuf, *recv_len);
 113 #else
 114                         res = dm_i2c_read(dev, 0, recvbuf, *recv_len);
 115 #endif
 116         }
 117         if (res) {
 118                 printf("i2c_read returned %d (rlen=%d)\n", res, *recv_len);
 119 #ifdef DEBUG
 120                 print_buffer(0, recvbuf, 1, *recv_len, 0);
 121 #endif
 122         }
 123
 124 #ifdef DEBUG
 125         if (!res) {
 126                 printf("read from TPM (%d bytes):\n", *recv_len);
 127                 print_buffer(0, recvbuf, 1, *recv_len, 0);
 128         }
 129 #endif
 130
 131         return res;
 132 }
 133
 134 static int tpm_atmel_twi_probe(struct udevice *dev)
 135 {
 136         return 0;
 137 }
 138
 139 static const struct udevice_id tpm_atmel_twi_ids[] = {
 140         { .compatible = "atmel,at97sc3204t"},
 141         { }
 142 };
 143
 144 static const struct tpm_ops tpm_atmel_twi_ops = {
 145         .open = tpm_atmel_twi_open,
 146         .close = tpm_atmel_twi_close,
 147         .xfer = tpm_atmel_twi_xfer,
 148         .get_desc = tpm_atmel_twi_get_desc,
 149 };
 150
 151 U_BOOT_DRIVER(tpm_atmel_twi) = {
 152         .name = "tpm_atmel_twi",
 153         .id = UCLASS_TPM,
 154         .of_match = tpm_atmel_twi_ids,
 155         .ops = &tpm_atmel_twi_ops,
 156         .probe = tpm_atmel_twi_probe,
 157 };