ixgbe: add methods for combined read and write operations

Some X550 procedures will be using CS4227 PHY and need to
perform combined read and write operations.  This patch
adds those methods.
Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe_phy.c

@@ -49,6 +49,188 @@ static enum ixgbe_phy_type ixgbe_get_phy_type_from_id(u32 phy_id);
 static s32 ixgbe_get_phy_id(struct ixgbe_hw *hw);
 static s32 ixgbe_identify_qsfp_module_generic(struct ixgbe_hw *hw);
 
+/**
+ *  ixgbe_out_i2c_byte_ack - Send I2C byte with ack
+ *  @hw: pointer to the hardware structure
+ *  @byte: byte to send
+ *
+ *  Returns an error code on error.
+ **/
+static s32 ixgbe_out_i2c_byte_ack(struct ixgbe_hw *hw, u8 byte)
+{
+	s32 status;
+
+	status = ixgbe_clock_out_i2c_byte(hw, byte);
+	if (status)
+		return status;
+	return ixgbe_get_i2c_ack(hw);
+}
+
+/**
+ *  ixgbe_in_i2c_byte_ack - Receive an I2C byte and send ack
+ *  @hw: pointer to the hardware structure
+ *  @byte: pointer to a u8 to receive the byte
+ *
+ *  Returns an error code on error.
+ **/
+static s32 ixgbe_in_i2c_byte_ack(struct ixgbe_hw *hw, u8 *byte)
+{
+	s32 status;
+
+	status = ixgbe_clock_in_i2c_byte(hw, byte);
+	if (status)
+		return status;
+	/* ACK */
+	return ixgbe_clock_out_i2c_bit(hw, false);
+}
+
+/**
+ *  ixgbe_ones_comp_byte_add - Perform one's complement addition
+ *  @add1: addend 1
+ *  @add2: addend 2
+ *
+ *  Returns one's complement 8-bit sum.
+ **/
+static u8 ixgbe_ones_comp_byte_add(u8 add1, u8 add2)
+{
+	u16 sum = add1 + add2;
+
+	sum = (sum & 0xFF) + (sum >> 8);
+	return sum & 0xFF;
+}
+
+/**
+ *  ixgbe_read_i2c_combined_generic - Perform I2C read combined operation
+ *  @hw: pointer to the hardware structure
+ *  @addr: I2C bus address to read from
+ *  @reg: I2C device register to read from
+ *  @val: pointer to location to receive read value
+ *
+ *  Returns an error code on error.
+ **/
+s32 ixgbe_read_i2c_combined_generic(struct ixgbe_hw *hw, u8 addr,
+				    u16 reg, u16 *val)
+{
+	u32 swfw_mask = hw->phy.phy_semaphore_mask;
+	int max_retry = 10;
+	int retry = 0;
+	u8 csum_byte;
+	u8 high_bits;
+	u8 low_bits;
+	u8 reg_high;
+	u8 csum;
+
+	reg_high = ((reg >> 7) & 0xFE) | 1;     /* Indicate read combined */
+	csum = ixgbe_ones_comp_byte_add(reg_high, reg & 0xFF);
+	csum = ~csum;
+	do {
+		if (hw->mac.ops.acquire_swfw_sync(hw, swfw_mask))
+			return IXGBE_ERR_SWFW_SYNC;
+		ixgbe_i2c_start(hw);
+		/* Device Address and write indication */
+		if (ixgbe_out_i2c_byte_ack(hw, addr))
+			goto fail;
+		/* Write bits 14:8 */
+		if (ixgbe_out_i2c_byte_ack(hw, reg_high))
+			goto fail;
+		/* Write bits 7:0 */
+		if (ixgbe_out_i2c_byte_ack(hw, reg & 0xFF))
+			goto fail;
+		/* Write csum */
+		if (ixgbe_out_i2c_byte_ack(hw, csum))
+			goto fail;
+		/* Re-start condition */
+		ixgbe_i2c_start(hw);
+		/* Device Address and read indication */
+		if (ixgbe_out_i2c_byte_ack(hw, addr | 1))
+			goto fail;
+		/* Get upper bits */
+		if (ixgbe_in_i2c_byte_ack(hw, &high_bits))
+			goto fail;
+		/* Get low bits */
+		if (ixgbe_in_i2c_byte_ack(hw, &low_bits))
+			goto fail;
+		/* Get csum */
+		if (ixgbe_clock_in_i2c_byte(hw, &csum_byte))
+			goto fail;
+		/* NACK */
+		if (ixgbe_clock_out_i2c_bit(hw, false))
+			goto fail;
+		ixgbe_i2c_stop(hw);
+		hw->mac.ops.release_swfw_sync(hw, swfw_mask);
+		*val = (high_bits << 8) | low_bits;
+		return 0;
+
+fail:
+		ixgbe_i2c_bus_clear(hw);
+		hw->mac.ops.release_swfw_sync(hw, swfw_mask);
+		retry++;
+		if (retry < max_retry)
+			hw_dbg(hw, "I2C byte read combined error - Retry.\n");
+		else
+			hw_dbg(hw, "I2C byte read combined error.\n");
+	} while (retry < max_retry);
+
+	return IXGBE_ERR_I2C;
+}
+
+/**
+ *  ixgbe_write_i2c_combined_generic - Perform I2C write combined operation
+ *  @hw: pointer to the hardware structure
+ *  @addr: I2C bus address to write to
+ *  @reg: I2C device register to write to
+ *  @val: value to write
+ *
+ *  Returns an error code on error.
+ **/
+s32 ixgbe_write_i2c_combined_generic(struct ixgbe_hw *hw,
+				     u8 addr, u16 reg, u16 val)
+{
+	int max_retry = 1;
+	int retry = 0;
+	u8 reg_high;
+	u8 csum;
+
+	reg_high = (reg >> 7) & 0xFE;   /* Indicate write combined */
+	csum = ixgbe_ones_comp_byte_add(reg_high, reg & 0xFF);
+	csum = ixgbe_ones_comp_byte_add(csum, val >> 8);
+	csum = ixgbe_ones_comp_byte_add(csum, val & 0xFF);
+	csum = ~csum;
+	do {
+		ixgbe_i2c_start(hw);
+		/* Device Address and write indication */
+		if (ixgbe_out_i2c_byte_ack(hw, addr))
+			goto fail;
+		/* Write bits 14:8 */
+		if (ixgbe_out_i2c_byte_ack(hw, reg_high))
+			goto fail;
+		/* Write bits 7:0 */
+		if (ixgbe_out_i2c_byte_ack(hw, reg & 0xFF))
+			goto fail;
+		/* Write data 15:8 */
+		if (ixgbe_out_i2c_byte_ack(hw, val >> 8))
+			goto fail;
+		/* Write data 7:0 */
+		if (ixgbe_out_i2c_byte_ack(hw, val & 0xFF))
+			goto fail;
+		/* Write csum */
+		if (ixgbe_out_i2c_byte_ack(hw, csum))
+			goto fail;
+		ixgbe_i2c_stop(hw);
+		return 0;
+
+fail:
+		ixgbe_i2c_bus_clear(hw);
+		retry++;
+		if (retry < max_retry)
+			hw_dbg(hw, "I2C byte write combined error - Retry.\n");
+		else
+			hw_dbg(hw, "I2C byte write combined error.\n");
+	} while (retry < max_retry);
+
+	return IXGBE_ERR_I2C;
+}
+
 /**
  *  ixgbe_identify_phy_generic - Get physical layer module
  *  @hw: pointer to hardware structure

drivers/net/ethernet/intel/ixgbe/ixgbe_phy.h

@@ -157,4 +157,8 @@ s32 ixgbe_read_i2c_sff8472_generic(struct ixgbe_hw *hw, u8 byte_offset,
 				   u8 *sff8472_data);
 s32 ixgbe_write_i2c_eeprom_generic(struct ixgbe_hw *hw, u8 byte_offset,
 				   u8 eeprom_data);
+s32 ixgbe_read_i2c_combined_generic(struct ixgbe_hw *hw, u8 addr,
+				    u16 reg, u16 *val);
+s32 ixgbe_write_i2c_combined_generic(struct ixgbe_hw *hw, u8 addr,
+				     u16 reg, u16 val);
 #endif /* _IXGBE_PHY_H_ */

drivers/net/ethernet/intel/ixgbe/ixgbe_type.h

@@ -2960,6 +2960,8 @@ struct ixgbe_phy_operations {
 	s32 (*read_i2c_sff8472)(struct ixgbe_hw *, u8 , u8 *);
 	s32 (*read_i2c_eeprom)(struct ixgbe_hw *, u8 , u8 *);
 	s32 (*write_i2c_eeprom)(struct ixgbe_hw *, u8, u8);
+	s32 (*read_i2c_combined)(struct ixgbe_hw *, u8 addr, u16 reg, u16 *val);
+	s32 (*write_i2c_combined)(struct ixgbe_hw *, u8 addr, u16 reg, u16 val);
 	s32 (*check_overtemp)(struct ixgbe_hw *);
 };