openwrt/target/linux/generic/pending-5.4/770-01-net-ethernet-mtk_eth_soc-significantly-reduce-mdio-b.patch
Felix Fietkau b5d425af23 mediatek/ramips: unify ethernet driver fixes and add performance optimizations
Increase DMA burst size and tx ring size and optimize tx processing

Signed-off-by: Felix Fietkau <nbd@nbd.name>
2020-09-01 17:01:56 +02:00

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Diff

From: Felix Fietkau <nbd@nbd.name>
Date: Mon, 8 Jun 2020 17:02:39 +0200
Subject: [PATCH] net: ethernet: mtk_eth_soc: significantly reduce mdio bus
access latency
usleep_range often ends up sleeping much longer than the 10-20us provided
as a range here. This causes significant latency in mdio bus acceses,
which easily adds multiple seconds to the boot time on MT7621 when polling
DSA slave ports.
Use cond_resched instead of usleep_range, since the MDIO access does not
take much time
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -85,7 +85,7 @@ static int mtk_mdio_busy_wait(struct mtk
return 0;
if (time_after(jiffies, t_start + PHY_IAC_TIMEOUT))
break;
- usleep_range(10, 20);
+ cond_resched();
}
dev_err(eth->dev, "mdio: MDIO timeout\n");