realtek: eth: use free floating rings for RTL838x

The ring counters on RTL83xx allow a space of up to 15 entries.
But rings can be filled faster than data is received and might be
much larger defined (128 at the moment). Also NAPI processing
allows much more than 15 packets to be processed in one chunk.
Disable the counters and let the hardware automatically detect
the available buffers by the ownership flag. With this disable
a pseudo workaround that tried to mitigate the buffer filling
on RTL838x due to wrong setup.

Remark. This commit fixes several inconsistencies in the setup
code. RTL838x runs the setup twice with different values. RTL839x
does not run the setup at all.

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/21856
Signed-off-by: Robert Marko <robimarko@gmail.com>

diff --git a/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c b/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c
index d27c7501528a5de3b61e05ed43665dbc80f94798..529658121f44577daff8ecf8c56e9f2ada7249d9 100644 (file)
--- a/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c
+++ b/target/linux/realtek/files-6.12/drivers/net/ethernet/rtl838x_eth.c
@@ -217,14 +217,9 @@ struct rteth_ctrl {
  * When the content reaches the ring size, the ASIC no longer adds
  * packets to this receive queue.
  */
-static void rteth_838x_update_counter(int r, int released)
+static void rteth_83xx_update_counter(int r, int released)
 {
-       /* This feature is not available on RTL838x SoCs */
-}
-
-static void rteth_839x_update_counter(int r, int released)
-{
-       /* This feature is not available on RTL839x SoCs */
+       /* Free floating rings without space tracking */
 }
 
 static void rteth_930x_update_counter(int r, int released)
@@ -479,8 +474,8 @@ static void rteth_838x_hw_reset(struct rteth_ctrl *ctrl)
 
        rteth_nic_reset(ctrl, 0xc);
 
-       /* Setup Head of Line */
-       sw_w32(0, RTL838X_DMA_IF_RX_RING_SIZE);  /* Disabled on RTL8380 */
+       /* Free floating rings without space tracking */
+       sw_w32(0, RTL838X_DMA_IF_RX_RING_SIZE);
 }
 
 static void rteth_839x_hw_reset(struct rteth_ctrl *ctrl)
@@ -501,9 +496,6 @@ static void rteth_839x_hw_reset(struct rteth_ctrl *ctrl)
 
        rteth_nic_reset(ctrl, 0xc);
 
-       /* Setup Head of Line */
-       sw_w32(0xffffffff, RTL839X_DMA_IF_RX_RING_CNTR);
-
        /* Re-enable link change interrupt */
        sw_w32(0xffffffff, RTL839X_ISR_PORT_LINK_STS_CHG);
        sw_w32(0xffffffff, RTL839X_ISR_PORT_LINK_STS_CHG + 4);
@@ -513,6 +505,9 @@ static void rteth_839x_hw_reset(struct rteth_ctrl *ctrl)
        /* Restore notification settings: on RTL838x these bits are null */
        sw_w32_mask(7 << 20, int_saved & (7 << 20), ctrl->r->dma_if_intr_msk);
        sw_w32(nbuf, RTL839X_DMA_IF_NBUF_BASE_DESC_ADDR_CTRL);
+
+       /* Free floating rings without space tracking */
+       sw_w32(0, RTL839X_DMA_IF_RX_RING_SIZE);
 }
 
 static void rteth_93xx_hw_reset(struct rteth_ctrl *ctrl)
@@ -551,9 +546,6 @@ static void rteth_hw_ring_setup(struct rteth_ctrl *ctrl)
 
 static void rtl838x_hw_en_rxtx(struct rteth_ctrl *ctrl)
 {
-       /* Disable Head of Line features for all RX rings */
-       sw_w32(0xffffffff, ctrl->r->dma_if_rx_ring_size(0));
-
        /* Truncate RX buffer to DEFAULT_MTU bytes, pad TX */
        sw_w32((DEFAULT_MTU << 16) | RX_TRUNCATE_EN_83XX | TX_PAD_EN_838X, ctrl->r->dma_if_ctrl);
 
@@ -1077,18 +1069,6 @@ static int rtl838x_hw_receive(struct net_device *dev, int r, int budget)
 
                skb = netdev_alloc_skb_ip_align(dev, len);
                if (likely(skb)) {
-                       /* BUG: Prevent bug on RTL838x SoCs */
-                       if (ctrl->r->family_id == RTL8380_FAMILY_ID) {
-                               sw_w32(0xffffffff, ctrl->r->dma_if_rx_ring_size(0));
-                               for (int i = 0; i < ctrl->rxrings; i++) {
-                                       unsigned int val;
-
-                                       /* Update each ring cnt */
-                                       val = sw_r32(ctrl->r->dma_if_rx_ring_cntr(i));
-                                       sw_w32(val, ctrl->r->dma_if_rx_ring_cntr(i));
-                               }
-                       }
-
                        /* Make sure data is visible */
                        mb();
                        skb_put_data(skb, (u8 *)KSEG1ADDR(data), len);
@@ -1473,7 +1453,7 @@ static const struct rteth_config rteth_838x_cfg = {
        .get_mac_tx_pause_sts = rtl838x_get_mac_tx_pause_sts,
        .mac = RTL838X_MAC,
        .l2_tbl_flush_ctrl = RTL838X_L2_TBL_FLUSH_CTRL,
-       .update_counter = rteth_838x_update_counter,
+       .update_counter = rteth_83xx_update_counter,
        .create_tx_header = rteth_838x_create_tx_header,
        .decode_tag = rteth_838x_decode_tag,
        .hw_reset = &rteth_838x_hw_reset,
@@ -1517,7 +1497,7 @@ static const struct rteth_config rteth_839x_cfg = {
        .get_mac_tx_pause_sts = rtl839x_get_mac_tx_pause_sts,
        .mac = RTL839X_MAC,
        .l2_tbl_flush_ctrl = RTL839X_L2_TBL_FLUSH_CTRL,
-       .update_counter = rteth_839x_update_counter,
+       .update_counter = rteth_83xx_update_counter,
        .create_tx_header = rteth_839x_create_tx_header,
        .decode_tag = rteth_839x_decode_tag,
        .hw_reset = &rteth_839x_hw_reset,