From: Takamitsu Iwai Date: Fri, 6 Sep 2024 02:17:19 +0000 (+0900) Subject: e1000e: Remove duplicated writel() in e1000_configure_tx/rx() X-Git-Tag: v6.13-rc1~135^2~364^2~2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0cab3b0f8306a9ecd11b4c72ca4b890ae816193c;p=thirdparty%2Flinux.git e1000e: Remove duplicated writel() in e1000_configure_tx/rx() 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 Signed-off-by: Takamitsu Iwai Tested-by: Mor Bar-Gabay Signed-off-by: Tony Nguyen --- diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c index f103249b12fac..9c9d4cb7c7357 100644 --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -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);