| From 2a2ccfa44e56c45dfd1230f6efb3ec0a4a677f0a Mon Sep 17 00:00:00 2001 |
| From: Alex Marginean <alexandru.marginean@nxp.com> |
| Date: Wed, 15 Jan 2020 15:49:11 +0200 |
| Subject: [PATCH] drivers: net: dsa: felix: don't restart PCS SGMII AN if not |
| needed |
| |
| Some PHYs like VSC8234 don't like it when AN restarts on their system side |
| and they restart line side AN too, going into an endless link up/down loop. |
| Don't restart PCS AN if link is up already. |
| |
| Suggested-by: Vladimir Oltean <vladimir.oltean@nxp.com> |
| Signed-off-by: Alex Marginean <alexandru.marginean@nxp.com> |
| --- |
| drivers/net/dsa/ocelot/felix_vsc9959.c | 15 +++++++++++++++ |
| 1 file changed, 15 insertions(+) |
| |
| --- a/drivers/net/dsa/ocelot/felix_vsc9959.c |
| +++ b/drivers/net/dsa/ocelot/felix_vsc9959.c |
| @@ -648,7 +648,22 @@ static void vsc9959_pcs_init_sgmii(struc |
| unsigned int link_an_mode, |
| const struct phylink_link_state *state) |
| { |
| + int bmsr, bmcr; |
| + |
| if (link_an_mode == MLO_AN_INBAND) { |
| + /* Some PHYs like VSC8234 don't like it when AN restarts on |
| + * their system side and they restart line side AN too, going |
| + * into an endless link up/down loop. Don't restart PCS AN if |
| + * link is up already. |
| + * We do check that AN is enabled just in case this is the 1st |
| + * call, PCS detects a carrier but AN is disabled from power on |
| + * or by boot loader. |
| + */ |
| + bmcr = phy_read(pcs, MII_BMCR); |
| + bmsr = phy_read(pcs, MII_BMSR); |
| + if ((bmcr & BMCR_ANENABLE) && (bmsr & BMSR_LSTATUS)) |
| + return; |
| + |
| /* SGMII spec requires tx_config_Reg[15:0] to be exactly 0x4001 |
| * for the MAC PCS in order to acknowledge the AN. |
| */ |