lib: tenstorrent: bh_arc: dw_apb_i2c.c: init i2c only once

Initialize the I2C only once.

Signed-off-by: Alex Apostolu <aapostolu@tenstorrent.com>

Author: alexapostolu

lib/tenstorrent/bh_arc/dw_apb_i2c.c

@@ -155,6 +155,9 @@ extern uint8_t asic_state;
 /* i2c_target_config for Zephyr callbacks in I2C slave mode */
 struct i2c_target_config i2c_target_config[3];
 
+/* Static initialization flags for each I2C instance */
+static bool i2c_initialized[3] = {false, false, false};
+
 static inline uint32_t GetI2CBaseAddress(uint32_t id)
 {
 	switch (id) {
@@ -258,6 +261,11 @@ void I2CRecoverBus(uint32_t id)
 	WriteReg(RESET_UNIT_I2C_CNTL_REG_ADDR, i2c_rst_cntl | BIT(id));
 	/* Reenable I2C controller */
 	WriteReg(GetI2CRegAddr(id, GET_I2C_OFFSET(IC_ENABLE)), 1);
+
+	/* Reset initialization flag for this instance after recovery */
+	if (id < 3) {
+		i2c_initialized[id] = false;
+	}
 }
 
 static void WaitTxFifoEmpty(uint32_t id)
@@ -417,6 +425,24 @@ void I2CInit(I2CMode mode, uint32_t slave_addr, I2CSpeedMode speed, uint32_t id)
 		return;
 	}
 
+	/* Check if this I2C instance is already initialized */
+	if (id < 3 && i2c_initialized[id]) {
+		/* Only update target address if it's different */
+		if (mode == I2CMst) {
+			uint32_t current_tar = ReadReg(GetI2CRegAddr(id, GET_I2C_OFFSET(IC_TAR))) & 
+					       DW_APB_I2C_IC_TAR_IC_TAR_MASK;
+			if (current_tar != (slave_addr & DW_APB_I2C_IC_TAR_IC_TAR_MASK)) {
+				WriteReg(GetI2CRegAddr(id, GET_I2C_OFFSET(IC_ENABLE)), 0);
+				Wait(10 * WAIT_1US);
+				WriteReg(GetI2CRegAddr(id, GET_I2C_OFFSET(IC_TAR)),
+					 slave_addr & DW_APB_I2C_IC_TAR_IC_TAR_MASK);
+				WriteReg(GetI2CRegAddr(id, GET_I2C_OFFSET(IC_ENABLE)), 1);
+				Wait(10 * WAIT_1US);
+			}
+		}
+		return;
+	}
+
 	WaitTxFifoEmpty(id);
 	WaitMasterIdle(id);
 
@@ -469,6 +495,11 @@ void I2CInit(I2CMode mode, uint32_t slave_addr, I2CSpeedMode speed, uint32_t id)
 
 	WriteReg(GetI2CRegAddr(id, GET_I2C_OFFSET(IC_ENABLE)), 1);
 	Wait(10 * WAIT_1US);
+
+	/* Mark this I2C instance as initialized */
+	if (id < 3) {
+		i2c_initialized[id] = true;
+	}
 }
 
 /* Resets the all I2C controller instances */
@@ -480,6 +511,11 @@ void I2CReset(void)
 	Wait(WAIT_1US);
 	WriteReg(RESET_UNIT_I2C_CNTL_REG_ADDR, i2c_cntl & ~RESET_UNIT_I2C_CNTL_RESET_MASK);
 	Wait(WAIT_1US);
+
+	/* Reset initialization flags after hardware reset */
+	for (int i = 0; i < 3; i++) {
+		i2c_initialized[i] = false;
+	}
 }
 
 /* Generalized transaction function called by I2CWriteBytes and I2CReadBytes, implements SMBUS write