From cb9f97f0639625dfcc3e7df0cde5bb0ebd0fbcc9 Mon Sep 17 00:00:00 2001
From: Dimitar Tomov <dimi@wolfssl.com>
Date: Wed, 10 Feb 2021 19:45:48 +0200
Subject: [PATCH] Add tpm_io callback for STM32 CubeMX I2C HAL

Signed-off-by: Dimitar Tomov <dimi@wolfssl.com>
---
 examples/tpm_io.c | 81 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 76 insertions(+), 5 deletions(-)

diff --git a/examples/tpm_io.c b/examples/tpm_io.c
index afe2858..fec2bc8 100644
--- a/examples/tpm_io.c
+++ b/examples/tpm_io.c
@@ -89,8 +89,10 @@
         #endif
     #endif
 
+#elif defined(WOLFSSL_STM32_CUBEMX_I2C)
+    #define TPM2_I2C_ADDR 0x2e
 
-#elif defined(WOLFSSL_STM32_CUBEMX)
+#elif defined(WOLFSSL_STM32_CUBEMX_SPI)
 
 #elif defined(WOLFSSL_ATMEL)
     #include "asf.h"
@@ -323,8 +325,74 @@
     }
 #endif /* WOLFTPM_I2C */
 
-#elif defined(WOLFSSL_STM32_CUBEMX)
-    /* STM32 CubeMX Hal */
+#elif defined(WOLFSSL_STM32_CUBEMX_I2C)
+    /* STM32 CubeMX HAL I2C */
+    #define STM32_CUBEMX_I2C_TIMEOUT 250
+    static int i2c_read(void* userCtx, word32 reg, byte* data, int len)
+    {
+        int rc;
+        int i2cAddr = (TPM2_I2C_ADDR << 1) | 0x01; /* For I2C read LSB is 1 */
+        byte buf[MAX_SPI_FRAMESIZE+1];
+        I2C_HandleTypeDef* hi2c = (I2C_HandleTypeDef*)userCtx;
+
+        /* TIS layer should never provide a buffer larger than this,
+           but double check for good coding practice */
+        if (len > MAX_SPI_FRAMESIZE)
+            return BAD_FUNC_ARG;
+
+        buf[0] = (reg & 0xFF);
+        rc = HAL_I2C_Master_Receive(&hi2c, i2cAddr, data, len, STM32_CUBEMX_I2C_TIMEOUT);
+
+        if (rc != -1) {
+            XMEMCPY(data, buf+1, len);
+            return TPM_RC_SUCCESS;
+        }
+
+        return TPM_RC_FAILURE;
+    }
+
+    static int i2c_write(void* userCtx, word32 reg, byte* data, int len)
+    {
+        int rc;
+        int i2cAddr = (TPM2_I2C_ADDR << 1); /* I2C write operation, LSB is 0 */
+        byte buf[MAX_SPI_FRAMESIZE+1];
+        I2C_HandleTypeDef* hi2c = (I2C_HandleTypeDef*)userCtx;
+
+        /* TIS layer should never provide a buffer larger than this,
+           but double check for good coding practice */
+        if (len > MAX_SPI_FRAMESIZE)
+            return BAD_FUNC_ARG;
+
+        buf[0] = (reg & 0xFF); /* TPM register address */
+        XMEMCPY(buf + 1, data, len);
+        rc = HAL_I2C_Master_Transmit(&hi2c, TPM2_I2C_ADDR << 1, buf, len);
+
+        if (rc != -1) {
+            return TPM_RC_SUCCESS;
+        }
+
+        return TPM_RC_FAILURE;
+    }
+
+    static int TPM2_IoCb_STCubeMX_I2C(TPM2_CTX* ctx, int isRead, word32 addr,
+        byte* buf, word16 size, void* userCtx)
+    {
+        int ret = TPM_RC_FAILURE;
+
+        if (userCtx != NULL) {
+            if (isRead)
+                ret = i2c_read(userCtx, addr, buf, size);
+            else
+                ret = i2c_write(userCtx, addr, buf, size);
+        }
+
+        (void)ctx;
+
+        return ret;
+    } /* WOLFSSL_STM32_CUBEMX_SPI */
+
+#elif defined(WOLFSSL_STM32_CUBEMX_SPI)
+    /* STM32 CubeMX Hal SPI */
     #define STM32_CUBEMX_SPI_TIMEOUT 250
     static int TPM2_IoCb_STCubeMX_SPI(TPM2_CTX* ctx, const byte* txBuf, byte* rxBuf,
         word16 xferSz, void* userCtx)
@@ -396,7 +464,7 @@
         (void)ctx;
 
         return ret;
-    }
+    } /* WOLFSSL_STM32_CUBEMX_SPI */
 
 #elif defined(WOLFSSL_ATMEL)
     /* Atmel ASF */
@@ -772,7 +840,7 @@ int TPM2_IoCb(TPM2_CTX* ctx, int isRead, word32 addr, byte* buf, word16 size,
     void* userCtx)
 {
     int ret = TPM_RC_FAILURE;
-#ifndef WOLFTPM_I2C
+#if !defined(WOLFTPM_I2C) && !defined(WOLFSSL_STM32_CUBEMX_I2C)
     byte txBuf[MAX_SPI_FRAMESIZE+TPM_TIS_HEADER_SZ];
     byte rxBuf[MAX_SPI_FRAMESIZE+TPM_TIS_HEADER_SZ];
 #endif
@@ -799,6 +867,9 @@ int TPM2_IoCb(TPM2_CTX* ctx, int isRead, word32 addr, byte* buf, word16 size,
         (void)size;
         (void)userCtx;
     #endif
+#elif defined(WOLFSSL_STM32_CUBEMX_I2C)
+    /* Use STM32 CubeMX HAL for I2C */
+    ret = TPM2_IoCb_STCubeMX_I2C(ctx, isRead, addr, buf, size, userCtx);
 #else
     /* Build SPI format buffer */
     if (isRead) {