[PATCH net-next 05/14] net: ethernet: mtk_eth_soc: reduce MDIO bus access latency
From: Ilya Lipnitskiy <hidden>
Date: 2021-04-22 04:09:58
Also in:
linux-arm-kernel, linux-mediatek, lkml
Subsystem:
mediatek ethernet driver, networking drivers, the rest · Maintainers:
Felix Fietkau, Lorenzo Bianconi, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Felix Fietkau <nbd@nbd.name> 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 udelay via readx_poll_timeout_atomic, since the MDIO access does not take much time Signed-off-by: Felix Fietkau <nbd@nbd.name> [Ilya: use readx_poll_timeout_atomic instead of cond_resched] Signed-off-by: Ilya Lipnitskiy <redacted> --- drivers/net/ethernet/mediatek/mtk_eth_soc.c | 18 ++++++++---------- drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 +- 2 files changed, 9 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 5cf64de3ddf8..a3958e99a29f 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c@@ -79,18 +79,16 @@ static u32 mtk_m32(struct mtk_eth *eth, u32 mask, u32 set, unsigned reg) static int mtk_mdio_busy_wait(struct mtk_eth *eth) { - unsigned long t_start = jiffies; + int ret; + u32 val; - while (1) { - if (!(mtk_r32(eth, MTK_PHY_IAC) & PHY_IAC_ACCESS)) - return 0; - if (time_after(jiffies, t_start + PHY_IAC_TIMEOUT)) - break; - usleep_range(10, 20); - } + ret = readx_poll_timeout_atomic(__raw_readl, eth->base + MTK_PHY_IAC, + val, !(val & PHY_IAC_ACCESS), + 5, PHY_IAC_TIMEOUT_US); + if (ret) + dev_err(eth->dev, "mdio: MDIO timeout\n"); - dev_err(eth->dev, "mdio: MDIO timeout\n"); - return -1; + return ret; } static u32 _mtk_mdio_write(struct mtk_eth *eth, u32 phy_addr,
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 875e67b41561..989342a7ae4a 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h@@ -327,7 +327,7 @@ #define PHY_IAC_START BIT(16) #define PHY_IAC_ADDR_SHIFT 20 #define PHY_IAC_REG_SHIFT 25 -#define PHY_IAC_TIMEOUT HZ +#define PHY_IAC_TIMEOUT_US 1000000 #define MTK_MAC_MISC 0x1000c #define MTK_MUX_TO_ESW BIT(0)
--
2.31.1