commit dbb942a2383b10662a679ab1477eedd283b09dcf
author Tasnim <tasnim.ouni@st.com> Fri Nov 10 11:21:51 2023 +0100
committer Tasnim <tasnim.ouni@st.com> Fri Nov 10 12:22:50 2023 +0100
tree 27a0197c3f5ab6acb625434215bee095d57c9971
parent 277a7bdf34098735da188be89d1b3908d6baddac

[LL][I2C] Update LL_I2C_HandleTranfer function to prevent undefined behavior of volatile usage before updating the CR2 register

Inc/stm32l5xx_ll_i2c.h

diff --git a/Inc/stm32l5xx_ll_i2c.h b/Inc/stm32l5xx_ll_i2c.h
index e9553e1..37d3856 100644
--- a/Inc/stm32l5xx_ll_i2c.h
+++ b/Inc/stm32l5xx_ll_i2c.h
@@ -2133,11 +2133,18 @@
 __STATIC_INLINE void LL_I2C_HandleTransfer(I2C_TypeDef *I2Cx, uint32_t SlaveAddr, uint32_t SlaveAddrSize,
                                            uint32_t TransferSize, uint32_t EndMode, uint32_t Request)
 {
+  /* Declaration of tmp to prevent undefined behavior of volatile usage */
+  uint32_t tmp = ((uint32_t)(((uint32_t)SlaveAddr & I2C_CR2_SADD) | \
+                             ((uint32_t)SlaveAddrSize & I2C_CR2_ADD10) | \
+                             (((uint32_t)TransferSize << I2C_CR2_NBYTES_Pos) & I2C_CR2_NBYTES) | \
+                             (uint32_t)EndMode | (uint32_t)Request) & (~0x80000000U));
+
+  /* update CR2 register */
   MODIFY_REG(I2Cx->CR2, I2C_CR2_SADD | I2C_CR2_ADD10 |
              (I2C_CR2_RD_WRN & (uint32_t)(Request >> (31U - I2C_CR2_RD_WRN_Pos))) |
              I2C_CR2_START | I2C_CR2_STOP | I2C_CR2_RELOAD |
              I2C_CR2_NBYTES | I2C_CR2_AUTOEND | I2C_CR2_HEAD10R,
-             SlaveAddr | SlaveAddrSize | (TransferSize << I2C_CR2_NBYTES_Pos) | EndMode | Request);
+             tmp);
 }
 
 /**