From 650a49bc65df6b0e0051a8f62d7c22d95a8f350d Mon Sep 17 00:00:00 2001 From: "Russell King (Oracle)" Date: Wed, 18 May 2022 15:55:07 +0100 Subject: [PATCH 08/12] net: mtk_eth_soc: add fixme comment for state->speed use Add a fixme comment for the last remaining incorrect usage of state->speed in the mac_config() method, which is strangely in a code path which is only run when the PHY interface mode changes. This means if we are in RGMII mode, changes in state->speed will not cause the INTF_MODE, TRGMII_RCK_CTRL and TRGMII_TCK_CTRL registers to be set according to the speed, nor will the TRGPLL clock be set to the correct value. Signed-off-by: Russell King (Oracle) Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c @@ -374,6 +374,14 @@ static void mtk_mac_config(struct phylin state->interface)) goto err_phy; } else { + /* FIXME: this is incorrect. Not only does it + * use state->speed (which is not guaranteed + * to be correct) but it also makes use of it + * in a code path that will only be reachable + * when the PHY interface mode changes, not + * when the speed changes. Consequently, RGMII + * is probably broken. + */ mtk_gmac0_rgmii_adjust(mac->hw, state->interface, state->speed);