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wolfTPM/hal/tpm_io_wolfhal.c

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/* tpm_io_wolfhal.c
*
* Copyright (C) 2006-2026 wolfSSL Inc.
*
* This file is part of wolfTPM.
*
* wolfTPM is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* wolfTPM is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
*/
/* This example shows IO interfaces for wolfHAL */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <wolftpm/tpm2.h>
#include <wolftpm/tpm2_tis.h>
#include "tpm_io.h"
/******************************************************************************/
/* --- BEGIN IO Callback Logic -- */
/******************************************************************************/
/* Included via tpm_io.c if WOLFTPM_INCLUDE_IO_FILE is defined */
#ifdef WOLFTPM_INCLUDE_IO_FILE
#if ! (defined(WOLFTPM_LINUX_DEV) || \
defined(WOLFTPM_SWTPM) || \
defined(WOLFTPM_WINAPI) )
#if defined(WOLFTPM_WOLFHAL)
/* Only pull in wolfHAL and the board definitions when this backend is
* selected, so the file compiles to nothing when built directly on a
* platform that does not have wolfHAL available. */
#include <wolfHAL/wolfHAL.h>
#include "board.h"
#ifdef WOLFTPM_I2C
/* board.h is supplied by the application, not by wolfTPM. It must
* describe how this board reaches the TPM. */
#ifndef BOARD_I2C_DEV
#error "wolfHAL: board.h must define BOARD_I2C_DEV (whal_I2c*)"
#endif
/* Carries the TPM target address (typically 0x2e) and bus speed. */
#ifndef BOARD_I2C_COM_CFG
#error "wolfHAL: board.h must define BOARD_I2C_COM_CFG (whal_I2c_ComCfg*)"
#endif
#ifdef TPM2_I2C_ADDR
#error "wolfHAL: TPM2_I2C_ADDR is unused, set addr in BOARD_I2C_COM_CFG"
#endif
#ifndef TPM_I2C_TRIES
#define TPM_I2C_TRIES 10
#endif
/* wolfHAL I2C */
int TPM2_IoCb_Wolfhal_I2C(TPM2_CTX* ctx, int isRead, word32 addr,
byte* buf, word16 size, void* userCtx)
{
int ret = TPM_RC_FAILURE;
whal_Error status;
int tries = TPM_I2C_TRIES;
/* wolfHAL takes an 8-bit register, the TIS layer hands us the full
* address. Narrow it explicitly rather than relying on conversion. */
uint8_t reg = (uint8_t)(addr & 0xFF);
/* Open the session. This applies the TPM target address and bus
* speed, and must precede any transfer. */
status = whal_I2c_StartCom(BOARD_I2C_DEV, BOARD_I2C_COM_CFG);
if (status != WHAL_SUCCESS) {
#ifdef WOLFTPM_DEBUG_VERBOSE
printf("I2C StartCom Failed: Status=%d\n", status);
#endif
return TPM_RC_FAILURE;
}
/* The TPM takes about 80us to wake up and NAKs until it is ready, so
* retry the transfer. StartCom only configures the peripheral, the
* NAK surfaces here where the bus is actually driven. */
do {
if (isRead) {
status = whal_I2c_ReadReg(BOARD_I2C_DEV, reg, buf, size);
}
else {
status = whal_I2c_WriteReg(BOARD_I2C_DEV, reg, buf, size);
}
if (status == WHAL_SUCCESS) {
break;
}
XSLEEP_MS(1);
} while (--tries > 0);
if (status == WHAL_SUCCESS) {
ret = TPM_RC_SUCCESS;
}
#ifdef WOLFTPM_DEBUG_VERBOSE
else {
printf("I2C %s Failed: Reg 0x%x, Sz %d, Status=%d (tries %d)\n",
isRead ? "Read" : "Write", reg, size, status,
TPM_I2C_TRIES - tries);
}
#endif
/* Always end the session, including on the error path above. A
* teardown failure leaves the bus in an unknown state, so it
* downgrades an otherwise successful transfer. */
status = whal_I2c_EndCom(BOARD_I2C_DEV);
if (status != WHAL_SUCCESS) {
#ifdef WOLFTPM_DEBUG_VERBOSE
printf("I2C EndCom Failed: Status=%d\n", status);
#endif
ret = TPM_RC_FAILURE;
}
(void)ctx;
(void)userCtx;
return ret;
}
#else /* wolfHAL SPI */
/* board.h is supplied by the application, not by wolfTPM. It must
* describe how this board reaches the TPM. */
#ifndef BOARD_SPI_DEV
#error "wolfHAL: board.h must define BOARD_SPI_DEV (whal_Spi*)"
#endif
#ifndef BOARD_SPI_COM_CFG
#error "wolfHAL: board.h must define BOARD_SPI_COM_CFG (whal_Spi_ComCfg*)"
#endif
#ifndef BOARD_GPIO_DEV
#error "wolfHAL: board.h must define BOARD_GPIO_DEV (whal_Gpio*) for chip select"
#endif
#ifndef BOARD_CS_PIN
#error "wolfHAL: board.h must define BOARD_CS_PIN (chip select pin, active low)"
#endif
int TPM2_IoCb_Wolfhal_SPI(TPM2_CTX* ctx, const byte* txBuf, byte* rxBuf,
word16 xferSz, void* userCtx)
{
int ret = TPM_RC_FAILURE;
whal_Error status;
#ifdef WOLFTPM_CHECK_WAIT_STATE
int timeout = TPM_SPI_WAIT_RETRY;
#endif
/* Open the transaction */
status = whal_Spi_StartCom(BOARD_SPI_DEV, BOARD_SPI_COM_CFG);
if (status != WHAL_SUCCESS) {
#ifdef WOLFTPM_DEBUG_VERBOSE
printf("SPI StartCom Failed: Status=%d\n", status);
#endif
return TPM_RC_FAILURE;
}
/* Assert chip select (active low) */
status = whal_Gpio_Set(BOARD_GPIO_DEV, BOARD_CS_PIN, 0);
if (status != WHAL_SUCCESS) {
#ifdef WOLFTPM_DEBUG_VERBOSE
printf("SPI CS assert Failed: Status=%d\n", status);
#endif
(void)whal_Spi_EndCom(BOARD_SPI_DEV);
return TPM_RC_FAILURE;
}
#ifdef WOLFTPM_CHECK_WAIT_STATE
/* Send Header */
status = whal_Spi_SendRecv(BOARD_SPI_DEV, txBuf, TPM_TIS_HEADER_SZ,
rxBuf, TPM_TIS_HEADER_SZ);
if (status != WHAL_SUCCESS)
goto exit;
/* Check for wait states */
if ((rxBuf[TPM_TIS_HEADER_SZ-1] & TPM_TIS_READY_MASK) == 0) {
do {
/* Check for SPI ready */
status = whal_Spi_SendRecv(BOARD_SPI_DEV, txBuf, 1,
rxBuf, 1);
if (status != WHAL_SUCCESS)
goto exit;
if (rxBuf[0] & TPM_TIS_READY_MASK)
break;
} while (--timeout > 0);
#ifdef WOLFTPM_DEBUG_TIMEOUT
printf("SPI Ready Wait %d\n", TPM_SPI_WAIT_RETRY - timeout);
#endif
if (timeout <= 0) {
#ifdef WOLFTPM_DEBUG_VERBOSE
printf("SPI Ready timeout after %d tries\n",
TPM_SPI_WAIT_RETRY);
#endif
goto exit; /* ret stays TPM_RC_FAILURE */
}
}
/* Send remainder of payload */
status = whal_Spi_SendRecv(BOARD_SPI_DEV,
&txBuf[TPM_TIS_HEADER_SZ], xferSz - TPM_TIS_HEADER_SZ,
&rxBuf[TPM_TIS_HEADER_SZ], xferSz - TPM_TIS_HEADER_SZ);
#else
/* Send Entire Message - no wait states */
status = whal_Spi_SendRecv(BOARD_SPI_DEV, txBuf, xferSz, rxBuf, xferSz);
#endif /* WOLFTPM_CHECK_WAIT_STATE */
if (status == WHAL_SUCCESS) {
ret = TPM_RC_SUCCESS;
}
#ifdef WOLFTPM_DEBUG_VERBOSE
else {
printf("SPI Failed: Xfer %d, Status=%d\n", xferSz, status);
}
#endif
#ifdef WOLFTPM_CHECK_WAIT_STATE
exit: /* only the wait state path bails out early */
#endif
/* Always tear down, including on the error paths above. A teardown
* failure leaves the bus in an unknown state, so it downgrades an
* otherwise successful transfer. */
status = whal_Gpio_Set(BOARD_GPIO_DEV, BOARD_CS_PIN, 1);
if (status != WHAL_SUCCESS) {
#ifdef WOLFTPM_DEBUG_VERBOSE
printf("SPI CS release Failed: Status=%d\n", status);
#endif
ret = TPM_RC_FAILURE;
}
status = whal_Spi_EndCom(BOARD_SPI_DEV);
if (status != WHAL_SUCCESS) {
#ifdef WOLFTPM_DEBUG_VERBOSE
printf("SPI EndCom Failed: Status=%d\n", status);
#endif
ret = TPM_RC_FAILURE;
}
(void)ctx;
(void)userCtx;
return ret;
}
#endif /* WOLFTPM_I2C */
#endif
#endif /* !(WOLFTPM_LINUX_DEV || WOLFTPM_SWTPM || WOLFTPM_WINAPI) */
#endif /* WOLFTPM_INCLUDE_IO_FILE */
/******************************************************************************/
/* --- END IO Callback Logic -- */
/******************************************************************************/
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