kernel: backport mtk_soc_eth fixes from v5.13

[openwrt/openwrt.git] / target / linux / generic / backport-5.10 / 610-v5.13-47-net-ethernet-mtk_eth_soc-only-read-the-full-RX-descr.patch

diff --git a/target/linux/generic/backport-5.10/610-v5.13-47-net-ethernet-mtk_eth_soc-only-read-the-full-RX-descr.patch b/target/linux/generic/backport-5.10/610-v5.13-47-net-ethernet-mtk_eth_soc-only-read-the-full-RX-descr.patch
new file mode 100644 (file)
index 0000000..f1a3fbd
--- /dev/null
+++ b/target/linux/generic/backport-5.10/610-v5.13-47-net-ethernet-mtk_eth_soc-only-read-the-full-RX-descr.patch
@@ -0,0 +1,49 @@
+From 816ac3e6e67bdd78d86226c6eb53619780750e92 Mon Sep 17 00:00:00 2001
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 22 Apr 2021 22:21:04 -0700
+Subject: [PATCH] net: ethernet: mtk_eth_soc: only read the full RX descriptor
+ if DMA is done
+
+Uncached memory access is expensive, and there is no need to access all
+descriptor words if we can't process them anyway
+
+Signed-off-by: Felix Fietkau <nbd@nbd.name>
+Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/ethernet/mediatek/mtk_eth_soc.c | 12 ++++++++----
+ 1 file changed, 8 insertions(+), 4 deletions(-)
+
+--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
++++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+@@ -777,13 +777,18 @@ static inline int mtk_max_buf_size(int f
+       return buf_size;
+ }
+ 
+-static inline void mtk_rx_get_desc(struct mtk_rx_dma *rxd,
++static inline bool mtk_rx_get_desc(struct mtk_rx_dma *rxd,
+                                  struct mtk_rx_dma *dma_rxd)
+ {
+-      rxd->rxd1 = READ_ONCE(dma_rxd->rxd1);
+       rxd->rxd2 = READ_ONCE(dma_rxd->rxd2);
++      if (!(rxd->rxd2 & RX_DMA_DONE))
++              return false;
++
++      rxd->rxd1 = READ_ONCE(dma_rxd->rxd1);
+       rxd->rxd3 = READ_ONCE(dma_rxd->rxd3);
+       rxd->rxd4 = READ_ONCE(dma_rxd->rxd4);
++
++      return true;
+ }
+ 
+ /* the qdma core needs scratch memory to be setup */
+@@ -1255,8 +1260,7 @@ static int mtk_poll_rx(struct napi_struc
+               rxd = &ring->dma[idx];
+               data = ring->data[idx];
+ 
+-              mtk_rx_get_desc(&trxd, rxd);
+-              if (!(trxd.rxd2 & RX_DMA_DONE))
++              if (!mtk_rx_get_desc(&trxd, rxd))
+                       break;
+ 
+               /* find out which mac the packet come from. values start at 1 */