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>

1 files changed, 2 insertions, 5 deletions

diff --git a/drivers/net/ixgbe/ixgbe_ethtool.c b/drivers/net/ixgbe/ixgbe_ethtool.c
index 410c29875785..f2efa3245352 100644
--- a/drivers/net/ixgbe/ixgbe_ethtool.c
+++ b/drivers/net/ixgbe/ixgbe_ethtool.c
@@ -847,11 +847,8 @@ static int ixgbe_get_eeprom(struct net_device *netdev,
         if (!eeprom_buff)
                 return -ENOMEM;
 
-        for (i = 0; i < eeprom_len; i++) {
-                if ((ret_val = hw->eeprom.ops.read(hw, first_word + i,
-                    &eeprom_buff[i])))
-                        break;
-        }
+        ret_val = hw->eeprom.ops.read_buffer(hw, first_word, eeprom_len,
+                                             eeprom_buff);
 
         /* Device's eeprom is always little-endian, word addressable */
         for (i = 0; i < eeprom_len; i++)