[PATCH 2/2] net: ethernet: mtk_eth_soc: only write values if needed

From: Daniel Golle
Date: Mon Mar 13 2023 - 20:37:30 EST


Only restart auto-negotiation and write link timer if actually
necessary. This prevents losing the link in case of minor
changes.

Fixes: 7e538372694b ("net: ethernet: mediatek: Re-add support SGMII")
Reviewed-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Tested-by: Bjørn Mork <bjorn@xxxxxxx>
Signed-off-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
---
drivers/net/ethernet/mediatek/mtk_sgmii.c | 24 +++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_sgmii.c b/drivers/net/ethernet/mediatek/mtk_sgmii.c
index 612f65bb0345..83976dc86887 100644
--- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
+++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
@@ -38,20 +38,16 @@ static int mtk_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
const unsigned long *advertising,
bool permit_pause_to_mac)
{
+ bool mode_changed = false, changed, use_an;
struct mtk_pcs *mpcs = pcs_to_mtk_pcs(pcs);
unsigned int rgc3, sgm_mode, bmcr;
int advertise, link_timer;
- bool changed, use_an;

advertise = phylink_mii_c22_pcs_encode_advertisement(interface,
advertising);
if (advertise < 0)
return advertise;

- link_timer = phylink_get_link_timer_ns(interface);
- if (link_timer < 0)
- return link_timer;
-
/* Clearing IF_MODE_BIT0 switches the PCS to BASE-X mode, and
* we assume that fixes it's speed at bitrate = line rate (in
* other words, 1000Mbps or 2500Mbps).
@@ -77,13 +73,16 @@ static int mtk_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
}

if (use_an) {
- /* FIXME: Do we need to set AN_RESTART here? */
- bmcr = SGMII_AN_RESTART | SGMII_AN_ENABLE;
+ bmcr = SGMII_AN_ENABLE;
} else {
bmcr = 0;
}

if (mpcs->interface != interface) {
+ link_timer = phylink_get_link_timer_ns(interface);
+ if (link_timer < 0)
+ return link_timer;
+
/* PHYA power down */
regmap_update_bits(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL,
SGMII_PHYA_PWD, SGMII_PHYA_PWD);
@@ -101,16 +100,17 @@ static int mtk_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
regmap_update_bits(mpcs->regmap, mpcs->ana_rgc3,
RG_PHY_SPEED_3_125G, rgc3);

+ /* Setup the link timer */
+ regmap_write(mpcs->regmap, SGMSYS_PCS_LINK_TIMER, link_timer / 2 / 8);
+
mpcs->interface = interface;
+ mode_changed = true;
}

/* Update the advertisement, noting whether it has changed */
regmap_update_bits_check(mpcs->regmap, SGMSYS_PCS_ADVERTISE,
SGMII_ADVERTISE, advertise, &changed);

- /* Setup the link timer and QPHY power up inside SGMIISYS */
- regmap_write(mpcs->regmap, SGMSYS_PCS_LINK_TIMER, link_timer / 2 / 8);
-
/* Update the sgmsys mode register */
regmap_update_bits(mpcs->regmap, SGMSYS_SGMII_MODE,
SGMII_REMOTE_FAULT_DIS | SGMII_SPEED_DUPLEX_AN |
@@ -118,7 +118,7 @@ static int mtk_pcs_config(struct phylink_pcs *pcs, unsigned int mode,

/* Update the BMCR */
regmap_update_bits(mpcs->regmap, SGMSYS_PCS_CONTROL_1,
- SGMII_AN_RESTART | SGMII_AN_ENABLE, bmcr);
+ SGMII_AN_ENABLE, bmcr);

/* Release PHYA power down state
* Only removing bit SGMII_PHYA_PWD isn't enough.
@@ -132,7 +132,7 @@ static int mtk_pcs_config(struct phylink_pcs *pcs, unsigned int mode,
usleep_range(50, 100);
regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, 0);

- return changed;
+ return changed || mode_changed;
}

static void mtk_pcs_restart_an(struct phylink_pcs *pcs)
--
2.39.2