drivers/tpm/tpm_atmel_twi.c

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public License as
   4  * published by the Free Software Foundation; either version 2 of
   5  * the License, or (at your option) any later version.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  15  * MA 02111-1307 USA
  16  */
  17
  18 #include <common.h>
  19 #include <tpm.h>
  20 #include <i2c.h>
  21 #include <asm/unaligned.h>
  22
  23 #define ATMEL_TPM_TIMEOUT_MS 5000 /* sufficient for anything but
  24                                      generating/exporting keys */
  25
  26 /*
  27  * tis_init()
  28  *
  29  * Initialize the TPM device. Returns 0 on success or -1 on
  30  * failure (in case device probing did not succeed).
  31  */
  32 int tis_init(void)
  33 {
  34         return 0;
  35 }
  36
  37 /*
  38  * tis_open()
  39  *
  40  * Requests access to locality 0 for the caller. After all commands have been
  41  * completed the caller is supposed to call tis_close().
  42  *
  43  * Returns 0 on success, -1 on failure.
  44  */
  45 int tis_open(void)
  46 {
  47         return 0;
  48 }
  49
  50 /*
  51  * tis_close()
  52  *
  53  * terminate the currect session with the TPM by releasing the locked
  54  * locality. Returns 0 on success of -1 on failure (in case lock
  55  * removal did not succeed).
  56  */
  57 int tis_close(void)
  58 {
  59         return 0;
  60 }
  61
  62 /*
  63  * tis_sendrecv()
  64  *
  65  * Send the requested data to the TPM and then try to get its response
  66  *
  67  * @sendbuf - buffer of the data to send
  68  * @send_size size of the data to send
  69  * @recvbuf - memory to save the response to
  70  * @recv_len - pointer to the size of the response buffer
  71  *
  72  * Returns 0 on success (and places the number of response bytes at recv_len)
  73  * or -1 on failure.
  74  */
  75 int tis_sendrecv(const uint8_t *sendbuf, size_t send_size, uint8_t *recvbuf,
  76                         size_t *recv_len)
  77 {
  78         int res;
  79         unsigned long start;
  80
  81 #ifdef DEBUG
  82         memset(recvbuf, 0xcc, *recv_len);
  83         printf("send to TPM (%d bytes, recv_len=%d):\n", send_size, *recv_len);
  84         print_buffer(0, (void *)sendbuf, 1, send_size, 0);
  85 #endif
  86
  87         res = i2c_write(0x29, 0, 0, (uchar *)sendbuf, send_size);
  88         if (res) {
  89                 printf("i2c_write returned %d\n", res);
  90                 return -1;
  91         }
  92
  93         start = get_timer(0);
  94         while ((res = i2c_read(0x29, 0, 0, recvbuf, 10))) {
  95                 if (get_timer(start) > ATMEL_TPM_TIMEOUT_MS) {
  96                         puts("tpm timed out\n");
  97                         return -1;
  98                 }
  99                 udelay(100);
 100         }
 101         if (!res) {
 102                 *recv_len = get_unaligned_be32(recvbuf + 2);
 103                 if (*recv_len > 10)
 104                         res = i2c_read(0x29, 0, 0, recvbuf, *recv_len);
 105         }
 106         if (res) {
 107                 printf("i2c_read returned %d (rlen=%d)\n", res, *recv_len);
 108 #ifdef DEBUG
 109                 print_buffer(0, recvbuf, 1, *recv_len, 0);
 110 #endif
 111         }
 112
 113 #ifdef DEBUG
 114         if (!res) {
 115                 printf("read from TPM (%d bytes):\n", *recv_len);
 116                 print_buffer(0, recvbuf, 1, *recv_len, 0);
 117         }
 118 #endif
 119
 120         return res;
 121 }