ixgbe: Allow reduced delays during SFP detection

Reduce the number of retries during PHY detection. This reduces
pauses when no SFP is present. Once an SFP is detected, the normal
retry count will be used.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

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

@@ -1730,6 +1730,21 @@ s32 ixgbe_write_i2c_eeprom_generic(struct ixgbe_hw *hw, u8 byte_offset,
 					  eeprom_data);
 }
 
+/**
+ * ixgbe_is_sfp_probe - Returns true if SFP is being detected
+ * @hw: pointer to hardware structure
+ * @offset: eeprom offset to be read
+ * @addr: I2C address to be read
+ */
+static bool ixgbe_is_sfp_probe(struct ixgbe_hw *hw, u8 offset, u8 addr)
+{
+	if (addr == IXGBE_I2C_EEPROM_DEV_ADDR &&
+	    offset == IXGBE_SFF_IDENTIFIER &&
+	    hw->phy.sfp_type == ixgbe_sfp_type_not_present)
+		return true;
+	return false;
+}
+
 /**
  *  ixgbe_read_i2c_byte_generic_int - Reads 8 bit word over I2C
  *  @hw: pointer to hardware structure
@@ -1749,6 +1764,9 @@ static s32 ixgbe_read_i2c_byte_generic_int(struct ixgbe_hw *hw, u8 byte_offset,
 	u32 swfw_mask = hw->phy.phy_semaphore_mask;
 	bool nack = true;
 
+	if (ixgbe_is_sfp_probe(hw, byte_offset, dev_addr))
+		max_retry = IXGBE_SFP_DETECT_RETRIES;
+
 	*data = 0;
 
 	do {

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

@@ -109,6 +109,8 @@
 #define IXGBE_I2C_T_SU_STO  4
 #define IXGBE_I2C_T_BUF     5
 
+#define IXGBE_SFP_DETECT_RETRIES	2
+
 #define IXGBE_TN_LASI_STATUS_REG        0x9005
 #define IXGBE_TN_LASI_STATUS_TEMP_ALARM 0x0008