Merge pull request wolfSSL#302 from dgarske/stm32_i2c

Fixes for STM32 I2C

IDE/STM32CUBE/wolftpm_test.c

@@ -18,6 +18,9 @@
  * along with wolfTPM.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifdef HAVE_CONFIG_H
+    #include <config.h>
+#endif
 #include "wolftpm_test.h"
 
 #ifndef SINGLE_THREADED
@@ -45,7 +48,7 @@ void wolfTPMTest(const void* argument)
     printf("Running wolfTPM Wrap Test...\n");
 
     /* Run wolfTPM wrap test */
-    ret = TPM2_Wrapper_Test(NULL);
+    ret = TPM2_Wrapper_Test(argument);
 
     printf("wolfTPM wrap test: Return code %d\n", ret);
 

IDE/STM32CUBE/wolftpm_test.h

@@ -21,9 +21,7 @@
 #ifndef WOLFTPM_TEST_H_
 #define WOLFTPM_TEST_H_
 
-#ifdef HAVE_CONFIG_H
-    #include <config.h>
-#endif
+#include <wolftpm/tpm2_types.h>
 
 #ifndef SINGLE_THREADED
 #include <cmsis_os.h>

hal/tpm_io.h

@@ -66,7 +66,7 @@
 #ifdef WOLFTPM_EXAMPLE_HAL
 
 #ifdef WOLFTPM_ADV_IO
-WOLFTPM_API int TPM2_IoCb(TPM2_CTX*, int isRead, word32 addr, byte* buf, word16 size,
+WOLFTPM_API int TPM2_IoCb(TPM2_CTX* ctx, int isRead, word32 addr, byte* buf, word16 size,
     void* userCtx);
 #else
 WOLFTPM_API int TPM2_IoCb(TPM2_CTX* ctx, const byte* txBuf, byte* rxBuf,

hal/tpm_io_linux.c

@@ -109,7 +109,7 @@
         int rc;
         struct i2c_rdwr_ioctl_data rdwr;
         struct i2c_msg msgs[2];
-        unsigned char buf[2];
+        unsigned char buf[1];
         int timeout = TPM_I2C_TRIES;
 
         rdwr.msgs = msgs;

hal/tpm_io_st.c

@@ -38,54 +38,93 @@
        defined(WOLFTPM_WINAPI) )
 
 #if defined(WOLFSSL_STM32_CUBEMX)
-    #ifdef WOLFTPM_I2C
+#ifdef WOLFTPM_I2C
+    #ifndef TPM_I2C_TRIES
+    #define TPM_I2C_TRIES 10
+    #endif
+    #ifndef TPM2_I2C_ADDR
     #define TPM2_I2C_ADDR 0x2e
+    #endif
+    #ifndef STM32_CUBEMX_I2C_TIMEOUT
+    #define STM32_CUBEMX_I2C_TIMEOUT 250 /* ticks/ms */
+    #endif
+
     /* 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];
+        int ret = TPM_RC_FAILURE;
+        HAL_StatusTypeDef status;
         I2C_HandleTypeDef* hi2c = (I2C_HandleTypeDef*)userCtx;
+        int i2cAddr = (TPM2_I2C_ADDR << 1) | 0x01; /* For I2C read LSB is 1 */
+        int timeout = TPM_I2C_TRIES;
+        byte buf[1];
 
         /* 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;
+        buf[0] = (reg & 0xFF); /* convert to simple 8-bit address for I2C */
+
+        /* The I2C takes about 80us to wake up and will NAK until it is ready */
+        do {
+            /* Write address to read from - retry until ack  */
+            status = HAL_I2C_Master_Transmit(hi2c, i2cAddr, buf, sizeof(buf),
+                STM32_CUBEMX_I2C_TIMEOUT);
+            HAL_Delay(1); /* guard time - should be 250us */
+        } while (status != HAL_OK && --timeout > 0);
+        if (status == HAL_OK) {
+            timeout = TPM_I2C_TRIES;
+            /* Perform read with retry */
+            do {
+                status = HAL_I2C_Master_Receive(hi2c, i2cAddr, data, len,
+                    STM32_CUBEMX_I2C_TIMEOUT);
+                if (status != HAL_OK)
+                    HAL_Delay(1); /* guard time - should be 250us */
+            } while (status != HAL_OK && --timeout > 0);
         }
-
-        return TPM_RC_FAILURE;
+        if (status == HAL_OK) {
+            ret = TPM_RC_SUCCESS;
+        }
+        else {
+            printf("I2C Read failure %d (tries %d)\n",
+                status, TPM_I2C_TRIES - timeout);
+        }
+        return ret;
     }
 
     static int i2c_write(void* userCtx, word32 reg, byte* data, int len)
     {
-        int rc;
+        int ret = TPM_RC_FAILURE;
+        HAL_StatusTypeDef status;
+        I2C_HandleTypeDef* hi2c = (I2C_HandleTypeDef*)userCtx;
         int i2cAddr = (TPM2_I2C_ADDR << 1); /* I2C write operation, LSB is 0 */
+        int timeout = TPM_I2C_TRIES;
         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 */
+        /* Build packet with TPM register and data */
+        buf[0] = (reg & 0xFF); /* convert to simple 8-bit address for I2C */
         XMEMCPY(buf + 1, data, len);
-        rc = HAL_I2C_Master_Transmit(&hi2c, TPM2_I2C_ADDR << 1, buf, len);
 
-        if (rc != -1) {
-            return TPM_RC_SUCCESS;
+        /* The I2C takes about 80us to wake up and will NAK until it is ready */
+        do {
+            status = HAL_I2C_Master_Transmit(hi2c, i2cAddr, buf, len+1,
+                STM32_CUBEMX_I2C_TIMEOUT);
+            if (status != HAL_OK)
+                HAL_Delay(1); /* guard time - should be 250us */
+        } while (status != HAL_OK && --timeout > 0);
+        if (status == HAL_OK) {
+            ret = TPM_RC_SUCCESS;
         }
-
-        return TPM_RC_FAILURE;
+        else {
+            printf("I2C Write failure %d\n", status);
+        }
+        return ret;
     }
 
     int TPM2_IoCb_STCubeMX_I2C(TPM2_CTX* ctx, int isRead, word32 addr,
@@ -105,7 +144,7 @@
         return ret;
     }
 
-    #else /* STM32 CubeMX Hal SPI */
+#else /* STM32 CubeMX Hal SPI */
     #define STM32_CUBEMX_SPI_TIMEOUT 250
     int TPM2_IoCb_STCubeMX_SPI(TPM2_CTX* ctx, const byte* txBuf, byte* rxBuf,
         word16 xferSz, void* userCtx)
@@ -178,7 +217,7 @@
 
         return ret;
     }
-    #endif /* WOLFTPM_I2C */
+#endif /* WOLFTPM_I2C */
 #endif
 #endif /* !(WOLFTPM_LINUX_DEV || WOLFTPM_SWTPM || WOLFTPM_WINAPI) */
 #endif /* WOLFTPM_INCLUDE_IO_FILE */