[PATCH net-next 3/4] net: ethernet: mtk_eth_soc: reduce rx ring size for older chipsets

[Felix Fietkau]

Commit c57e55819443 ("net: ethernet: mtk_eth_soc: handle dma buffer
size soc specific") resolved some tx timeout issues by bumping FQ and
tx ring sizes from 512 to 2048 entries (the value used in the MediaTek
SDK), however it also changed the rx ring size for all chipsets in the
same way.

Based on a few tests, it seems that a symmetric rx/tx ring size of 2048
really only makes sense on MT7988, which is capable of 10G ethernet links.

Older chipsets are typically deployed in systems that are more memory
constrained and don't actually need the larger rings to handle received
packets.

In order to reduce wasted memory set the ring size based on the SoC to
the following values:
- 2048 on MT7988
- 1024 on MT7986
- 512 (previous value) on everything else, except:
- 256 on RT5350 (the oldest supported chipset)

Fixes: c57e55819443 ("net: ethernet: mtk_eth_soc: handle dma buffer size soc specific")
Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 drivers/net/ethernet/mediatek/mtk_eth_soc.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 4e4ece5e257a..58b80af7230b 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -5140,7 +5140,7 @@ static const struct mtk_soc_data mt2701_data = {
 		.desc_size = sizeof(struct mtk_rx_dma),
 		.irq_done_mask = MTK_RX_DONE_INT,
 		.dma_l4_valid = RX_DMA_L4_VALID,
-		.dma_size = MTK_DMA_SIZE(2K),
+		.dma_size = MTK_DMA_SIZE(512),
 		.dma_max_len = MTK_TX_DMA_BUF_LEN,
 		.dma_len_offset = 16,
 	},
@@ -5168,7 +5168,7 @@ static const struct mtk_soc_data mt7621_data = {
 		.desc_size = sizeof(struct mtk_rx_dma),
 		.irq_done_mask = MTK_RX_DONE_INT,
 		.dma_l4_valid = RX_DMA_L4_VALID,
-		.dma_size = MTK_DMA_SIZE(2K),
+		.dma_size = MTK_DMA_SIZE(512),
 		.dma_max_len = MTK_TX_DMA_BUF_LEN,
 		.dma_len_offset = 16,
 	},
@@ -5198,7 +5198,7 @@ static const struct mtk_soc_data mt7622_data = {
 		.desc_size = sizeof(struct mtk_rx_dma),
 		.irq_done_mask = MTK_RX_DONE_INT,
 		.dma_l4_valid = RX_DMA_L4_VALID,
-		.dma_size = MTK_DMA_SIZE(2K),
+		.dma_size = MTK_DMA_SIZE(512),
 		.dma_max_len = MTK_TX_DMA_BUF_LEN,
 		.dma_len_offset = 16,
 	},
@@ -5227,7 +5227,7 @@ static const struct mtk_soc_data mt7623_data = {
 		.desc_size = sizeof(struct mtk_rx_dma),
 		.irq_done_mask = MTK_RX_DONE_INT,
 		.dma_l4_valid = RX_DMA_L4_VALID,
-		.dma_size = MTK_DMA_SIZE(2K),
+		.dma_size = MTK_DMA_SIZE(512),
 		.dma_max_len = MTK_TX_DMA_BUF_LEN,
 		.dma_len_offset = 16,
 	},
@@ -5253,7 +5253,7 @@ static const struct mtk_soc_data mt7629_data = {
 		.desc_size = sizeof(struct mtk_rx_dma),
 		.irq_done_mask = MTK_RX_DONE_INT,
 		.dma_l4_valid = RX_DMA_L4_VALID,
-		.dma_size = MTK_DMA_SIZE(2K),
+		.dma_size = MTK_DMA_SIZE(512),
 		.dma_max_len = MTK_TX_DMA_BUF_LEN,
 		.dma_len_offset = 16,
 	},
@@ -5285,7 +5285,7 @@ static const struct mtk_soc_data mt7981_data = {
 		.dma_l4_valid = RX_DMA_L4_VALID_V2,
 		.dma_max_len = MTK_TX_DMA_BUF_LEN,
 		.dma_len_offset = 16,
-		.dma_size = MTK_DMA_SIZE(2K),
+		.dma_size = MTK_DMA_SIZE(512),
 	},
 };
 
@@ -5315,7 +5315,7 @@ static const struct mtk_soc_data mt7986_data = {
 		.dma_l4_valid = RX_DMA_L4_VALID_V2,
 		.dma_max_len = MTK_TX_DMA_BUF_LEN,
 		.dma_len_offset = 16,
-		.dma_size = MTK_DMA_SIZE(2K),
+		.dma_size = MTK_DMA_SIZE(1K),
 	},
 };
 
@@ -5368,7 +5368,7 @@ static const struct mtk_soc_data rt5350_data = {
 		.dma_l4_valid = RX_DMA_L4_VALID_PDMA,
 		.dma_max_len = MTK_TX_DMA_BUF_LEN,
 		.dma_len_offset = 16,
-		.dma_size = MTK_DMA_SIZE(2K),
+		.dma_size = MTK_DMA_SIZE(256),
 	},
 };
 
-- 
2.47.0