e1000e: fix obscure comments

The interface to the device flash was modified in i219 and later HW.
This patch better describes the change and the impact on the driver.

CC: John W Linville <linville@tuxdriver.com>
Reported-by: John W Linville <linville@tuxdriver.com>
Signed-off-by: Yanir Lubetkin <yanirx.lubetkin@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index 7523f51..9d81c03 100644 (file)
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -603,12 +603,15 @@ static s32 e1000_init_nvm_params_ich8lan(struct e1000_hw *hw)
        u16 i;
        u32 nvm_size;
 
-       /* Can't read flash registers if the register set isn't mapped. */
        nvm->type = e1000_nvm_flash_sw;
-       /* in SPT, gfpreg doesn't exist. NVM size is taken from the
-        * STRAP register
-        */
+
        if (hw->mac.type == e1000_pch_spt) {
+               /* in SPT, gfpreg doesn't exist. NVM size is taken from the
+                * STRAP register. This is because in SPT the GbE Flash region
+                * is no longer accessed through the flash registers. Instead,
+                * the mechanism has changed, and the Flash region access
+                * registers are now implemented in GbE memory space.
+                */
                nvm->flash_base_addr = 0;
                nvm_size = (((er32(STRAP) >> 1) & 0x1F) + 1)
                    * NVM_SIZE_MULTIPLIER;
@@ -618,6 +621,7 @@ static s32 e1000_init_nvm_params_ich8lan(struct e1000_hw *hw)
                /* Set the base address for flash register access */
                hw->flash_address = hw->hw_addr + E1000_FLASH_BASE_ADDR;
        } else {
+               /* Can't read flash registers if register set isn't mapped. */
                if (!hw->flash_address) {
                        e_dbg("ERROR: Flash registers not mapped\n");
                        return -E1000_ERR_CONFIG;