@@ -2928,11 +2928,8 @@ static void e1000_configure_tx(struct e1000_adapter *adapter)
tx_ring->head = adapter->hw.hw_addr + E1000_TDH(0);
tx_ring->tail = adapter->hw.hw_addr + E1000_TDT(0);
- writel(0, tx_ring->head);
if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
e1000e_update_tdt_wa(tx_ring, 0);
- else
- writel(0, tx_ring->tail);
/* Set the Tx Interrupt Delay register */
ew32(TIDV, adapter->tx_int_delay);
@@ -3253,11 +3250,8 @@ static void e1000_configure_rx(struct e1000_adapter *adapter)
rx_ring->head = adapter->hw.hw_addr + E1000_RDH(0);
rx_ring->tail = adapter->hw.hw_addr + E1000_RDT(0);
- writel(0, rx_ring->head);
if (adapter->flags2 & FLAG2_PCIM2PCI_ARBITER_WA)
e1000e_update_rdt_wa(rx_ring, 0);
- else
- writel(0, rx_ring->tail);
/* Enable Receive Checksum Offload for TCP and UDP */
rxcsum = er32(RXCSUM);
Duplicated register initialization codes exist in e1000_configure_tx() and e1000_configure_rx(). For example, writel(0, tx_ring->head) writes 0 to tx_ring->head, which is adapter->hw.hw_addr + E1000_TDH(0). This initialization is already done in ew32(TDH(0), 0). ew32(TDH(0), 0) is equivalent to __ew32(hw, E1000_TDH(0), 0). It executes writel(0, hw->hw_addr + E1000_TDH(0)). Since variable hw is set to &adapter->hw, it is equal to writel(0, tx_ring->head). We can remove similar four writel() in e1000_configure_tx() and e1000_configure_rx(). commit 0845d45e900c ("e1000e: Modify Tx/Rx configurations to avoid null pointer dereferences in e1000_open") has introduced these writel(). This commit moved register writing to e1000_configure_tx/rx(), and as result, it caused duplication in e1000_configure_tx/rx(). This patch modifies the sequence of register writing, but removing these writes is safe because the same writes were already there before the commit. I also have checked the datasheets [0] [1] and have not found any description that we need to write RDH, RDT, TDH and TDT registers twice at initialization. Furthermore, we have tested this patch on an I219-V device physically. Link: https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/82577-gbe-phy-datasheet.pdf [0] Link: https://www.intel.com/content/www/us/en/content-details/613460/intel-82583v-gbe-controller-datasheet.html [1] Tested-by: Kohei Enju <enjuk@amazon.com> Signed-off-by: Takamitsu Iwai <takamitz@amazon.co.jp> --- v1->v2 modify commit message to explain the reason why we can remove these writes safely. v1 link https://lore.kernel.org/netdev/20240902061454.85744-1-takamitz@amazon.co.jp/ drivers/net/ethernet/intel/e1000e/netdev.c | 6 ------ 1 file changed, 6 deletions(-)