kernel: backport mtk_soc_eth fixes from v5.13

Fixes logic that leads to this error when booting mt7621 and other
devices that use the mediatek ethernet driver:
  [   23.144378] mtk_soc_eth 1e100000.ethernet: PPE table busy

The rest are mostly moved from pending-5.10 to backport-5.10 with a
couple of cleanups and improvements from upstream.

Refresh patches.

Links:
    https://git.kernel.org/netdev/net-next/c/c5d66587b890
    https://git.kernel.org/netdev/net-next/c/3f57d8c40fea
    https://git.kernel.org/netdev/net-next/c/5196c4178549
    https://git.kernel.org/netdev/net-next/c/787082ab9f7b
    https://git.kernel.org/netdev/net-next/c/c30c4a827390
    https://git.kernel.org/netdev/net-next/c/3630d519d7c3
    https://git.kernel.org/netdev/net-next/c/16ef670789b2
    https://git.kernel.org/netdev/net-next/c/59555a8d0dd3
    https://git.kernel.org/netdev/net-next/c/6b4423b258b9
    https://git.kernel.org/netdev/net-next/c/e9229ffd550b
    https://git.kernel.org/netdev/net-next/c/4e6bf609569c
    https://git.kernel.org/netdev/net-next/c/816ac3e6e67b
    https://git.kernel.org/netdev/net-next/c/16769a8923fa
    https://git.kernel.org/netdev/net-next/c/db2c7b353db3
    https://git.kernel.org/netdev/net-next/c/fa817272c37e
    https://git.kernel.org/netdev/net-next/c/3bc8e0aff23b

Fixes: f07fe36f22fc ("kernel: update flow offload patches to upstream version")
Cc: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/target/linux/generic/backport-5.10/610-v5.13-46-net-ethernet-mtk_eth_soc-cache-HW-pointer-of-last-fr.patch b/target/linux/generic/backport-5.10/610-v5.13-46-net-ethernet-mtk_eth_soc-cache-HW-pointer-of-last-fr.patch
new file mode 100644
index 0000000000..db21878e92
--- /dev/null
+++ b/target/linux/generic/backport-5.10/610-v5.13-46-net-ethernet-mtk_eth_soc-cache-HW-pointer-of-last-fr.patch
@@ -0,0 +1,73 @@
+From 4e6bf609569c59b6bd6acf4a607c096cbd820d79 Mon Sep 17 00:00:00 2001
+From: Felix Fietkau <nbd@nbd.name>
+Date: Thu, 22 Apr 2021 22:21:03 -0700
+Subject: [PATCH] net: ethernet: mtk_eth_soc: cache HW pointer of last freed TX
+ descriptor
+
+The value is only updated by the CPU, so it is cheaper to access from the
+ring data structure than from a hardware register.
+
+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 | 8 ++++----
+ drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 ++
+ 2 files changed, 6 insertions(+), 4 deletions(-)
+
+--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
++++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+@@ -1364,7 +1364,7 @@ static int mtk_poll_tx_qdma(struct mtk_e
+ 	struct mtk_tx_buf *tx_buf;
+ 	u32 cpu, dma;
+ 
+-	cpu = mtk_r32(eth, MTK_QTX_CRX_PTR);
++	cpu = ring->last_free_ptr;
+ 	dma = mtk_r32(eth, MTK_QTX_DRX_PTR);
+ 
+ 	desc = mtk_qdma_phys_to_virt(ring, cpu);
+@@ -1398,6 +1398,7 @@ static int mtk_poll_tx_qdma(struct mtk_e
+ 		cpu = next_cpu;
+ 	}
+ 
++	ring->last_free_ptr = cpu;
+ 	mtk_w32(eth, cpu, MTK_QTX_CRX_PTR);
+ 
+ 	return budget;
+@@ -1598,6 +1599,7 @@ static int mtk_tx_alloc(struct mtk_eth *
+ 	atomic_set(&ring->free_count, MTK_DMA_SIZE - 2);
+ 	ring->next_free = &ring->dma[0];
+ 	ring->last_free = &ring->dma[MTK_DMA_SIZE - 1];
++	ring->last_free_ptr = (u32)(ring->phys + ((MTK_DMA_SIZE - 1) * sz));
+ 	ring->thresh = MAX_SKB_FRAGS;
+ 
+ 	/* make sure that all changes to the dma ring are flushed before we
+@@ -1611,9 +1613,7 @@ static int mtk_tx_alloc(struct mtk_eth *
+ 		mtk_w32(eth,
+ 			ring->phys + ((MTK_DMA_SIZE - 1) * sz),
+ 			MTK_QTX_CRX_PTR);
+-		mtk_w32(eth,
+-			ring->phys + ((MTK_DMA_SIZE - 1) * sz),
+-			MTK_QTX_DRX_PTR);
++		mtk_w32(eth, ring->last_free_ptr, MTK_QTX_DRX_PTR);
+ 		mtk_w32(eth, (QDMA_RES_THRES << 8) | QDMA_RES_THRES,
+ 			MTK_QTX_CFG(0));
+ 	} else {
+--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
++++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+@@ -636,6 +636,7 @@ struct mtk_tx_buf {
+  * @phys:		The physical addr of tx_buf
+  * @next_free:		Pointer to the next free descriptor
+  * @last_free:		Pointer to the last free descriptor
++ * @last_free_ptr:	Hardware pointer value of the last free descriptor
+  * @thresh:		The threshold of minimum amount of free descriptors
+  * @free_count:		QDMA uses a linked list. Track how many free descriptors
+  *			are present
+@@ -646,6 +647,7 @@ struct mtk_tx_ring {
+ 	dma_addr_t phys;
+ 	struct mtk_tx_dma *next_free;
+ 	struct mtk_tx_dma *last_free;
++	u32 last_free_ptr;
+ 	u16 thresh;
+ 	atomic_t free_count;
+ 	int dma_size;