ixgbe: improve EEPROM read/write operations

Introduce buffered read/writes which greatly improves performance on
parts with large EEPROMs.

Previously reading/writing a word requires taking/releasing of synchronization
semaphores which adds 10ms to each operation. The optimization is to
read/write in buffers, but make sure the semaphore is not held for >500ms
according to the datasheet.

Since we can't read the EEPROM page size ixgbe_detect_eeprom_page_size() is
used to discover the EEPROM size when needed and keeps the result in
word_page_size for the rest of the run time.

Use buffered reads for ethtool -e.

Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
Tested-by: Evan Swanson <evan.swanson@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ixgbe/ixgbe_82598.c

@@ -1281,6 +1281,7 @@ static struct ixgbe_mac_operations mac_ops_82598 = {
 static struct ixgbe_eeprom_operations eeprom_ops_82598 = {
 	.init_params		= &ixgbe_init_eeprom_params_generic,
 	.read			= &ixgbe_read_eerd_generic,
+	.read_buffer		= &ixgbe_read_eerd_buffer_generic,
 	.calc_checksum          = &ixgbe_calc_eeprom_checksum_generic,
 	.validate_checksum	= &ixgbe_validate_eeprom_checksum_generic,
 	.update_checksum	= &ixgbe_update_eeprom_checksum_generic,

drivers/net/ixgbe/ixgbe_82599.c

@@ -2063,6 +2063,39 @@ static bool ixgbe_verify_lesm_fw_enabled_82599(struct ixgbe_hw *hw)
 	return lesm_enabled;
 }
 
+/**
+ *  ixgbe_read_eeprom_buffer_82599 - Read EEPROM word(s) using
+ *  fastest available method
+ *
+ *  @hw: pointer to hardware structure
+ *  @offset: offset of  word in EEPROM to read
+ *  @words: number of words
+ *  @data: word(s) read from the EEPROM
+ *
+ *  Retrieves 16 bit word(s) read from EEPROM
+ **/
+static s32 ixgbe_read_eeprom_buffer_82599(struct ixgbe_hw *hw, u16 offset,
+					  u16 words, u16 *data)
+{
+	struct ixgbe_eeprom_info *eeprom = &hw->eeprom;
+	s32 ret_val = IXGBE_ERR_CONFIG;
+
+	/*
+	 * If EEPROM is detected and can be addressed using 14 bits,
+	 * use EERD otherwise use bit bang
+	 */
+	if ((eeprom->type == ixgbe_eeprom_spi) &&
+	    (offset + (words - 1) <= IXGBE_EERD_MAX_ADDR))
+		ret_val = ixgbe_read_eerd_buffer_generic(hw, offset, words,
+							 data);
+	else
+		ret_val = ixgbe_read_eeprom_buffer_bit_bang_generic(hw, offset,
+								    words,
+								    data);
+
+	return ret_val;
+}
+
 /**
  *  ixgbe_read_eeprom_82599 - Read EEPROM word using
  *  fastest available method
@@ -2139,7 +2172,9 @@ static struct ixgbe_mac_operations mac_ops_82599 = {
 static struct ixgbe_eeprom_operations eeprom_ops_82599 = {
 	.init_params		= &ixgbe_init_eeprom_params_generic,
 	.read			= &ixgbe_read_eeprom_82599,
+	.read_buffer		= &ixgbe_read_eeprom_buffer_82599,
 	.write			= &ixgbe_write_eeprom_generic,
+	.write_buffer		= &ixgbe_write_eeprom_buffer_bit_bang_generic,
 	.calc_checksum		= &ixgbe_calc_eeprom_checksum_generic,
 	.validate_checksum	= &ixgbe_validate_eeprom_checksum_generic,
 	.update_checksum	= &ixgbe_update_eeprom_checksum_generic,