| Message ID | 8abed37d01d427bf9d27a157860c54375c994ea1.1700887953.git.daniel@makrotopia.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: phylink: set phy_state interface when attaching SFP | expand |
On Sat, Nov 25, 2023 at 04:56:20AM +0000, Daniel Golle wrote: > Assume 'usxgmii' being set as initial interface mode in DTS. Now plug > a 2.5GBase-T SFP module with exposed PHY. Currently this results in > a rather bizare situation: > > RTL8221B-VB-CG 2.5Gbps PHY (C45) i2c:sfp1-wan:11: rtl822x_c45_get_features: supported=00,00000000,00008000,000080ef > mtk_soc_eth 15100000.ethernet eth2: requesting link mode phy/2500base-x with support 00,00000000,00008000,0000e0ef > mtk_soc_eth 15100000.ethernet eth2: switched to phy/2500base-x link mode <<< !!!!!! > mtk_soc_eth 15100000.ethernet eth2: major config usxgmii <<< !!!!!! > mtk_soc_eth 15100000.ethernet eth2: phylink_mac_config: mode=phy/usxgmii/none adv=00,00000000,00000000,00000000 pause=00 > mtk_soc_eth 15100000.ethernet eth2: PHY [i2c:sfp1-wan:11] driver [RTL8221B-VB-CG 2.5Gbps PHY (C45)] (irq=POLL) > mtk_soc_eth 15100000.ethernet eth2: phy: 2500base-x setting supported 00,00000000,00008000,0000e0ef advertising 00,00000000,00008000,0000e0ef > > Then the link seemingly comes up (but is dead) because no subsequent > call to phylink_major_config actually configured MAC and PCS for > 2500base-x mode. > > This is because phylink_mac_initial_config() considers > pl->phy_state.interface if in MLO_AN_PHY mode while > phylink_sfp_set_config() only sets pl->link_config.interface. > > Also set pl->phy_state.interface in phylink_sfp_set_config(). Does it _actually_ matter? When the PHY's link comes up, doesn't it get sorted out for the real mode that will be used?
On Sat, Nov 25, 2023 at 08:28:20AM +0000, Russell King (Oracle) wrote: > On Sat, Nov 25, 2023 at 04:56:20AM +0000, Daniel Golle wrote: > > Assume 'usxgmii' being set as initial interface mode in DTS. Now plug > > a 2.5GBase-T SFP module with exposed PHY. Currently this results in > > a rather bizare situation: > > > > RTL8221B-VB-CG 2.5Gbps PHY (C45) i2c:sfp1-wan:11: rtl822x_c45_get_features: supported=00,00000000,00008000,000080ef > > mtk_soc_eth 15100000.ethernet eth2: requesting link mode phy/2500base-x with support 00,00000000,00008000,0000e0ef > > mtk_soc_eth 15100000.ethernet eth2: switched to phy/2500base-x link mode <<< !!!!!! > > mtk_soc_eth 15100000.ethernet eth2: major config usxgmii <<< !!!!!! > > mtk_soc_eth 15100000.ethernet eth2: phylink_mac_config: mode=phy/usxgmii/none adv=00,00000000,00000000,00000000 pause=00 > > mtk_soc_eth 15100000.ethernet eth2: PHY [i2c:sfp1-wan:11] driver [RTL8221B-VB-CG 2.5Gbps PHY (C45)] (irq=POLL) > > mtk_soc_eth 15100000.ethernet eth2: phy: 2500base-x setting supported 00,00000000,00008000,0000e0ef advertising 00,00000000,00008000,0000e0ef > > > > Then the link seemingly comes up (but is dead) because no subsequent > > call to phylink_major_config actually configured MAC and PCS for > > 2500base-x mode. > > > > This is because phylink_mac_initial_config() considers > > pl->phy_state.interface if in MLO_AN_PHY mode while > > phylink_sfp_set_config() only sets pl->link_config.interface. > > > > Also set pl->phy_state.interface in phylink_sfp_set_config(). > > Does it _actually_ matter? It does matter, I'm suggesting this change because the SFP module won't work without it. > When the PHY's link comes up, doesn't it get sorted out for the real > mode that will be used? That does happen once the interface mode *changes* to anything else, than 2500M/Full and the PHY driver sets state->interface to SGMII. However, initially it does *not* happen, probably because phylink ends up believing MAC and PCS are already operating in 2500base-x mode (but that's not the case). Previously (eg. with the BananaPi R3) this has not been a problem because the default interface mode defined in device tree anyway has also been 2500base-x. Now that I'm testing the same module with the R4 which uses usxgmii by default the problem surfaced.
On Fri, Dec 01, 2023 at 06:19:20PM +0000, Daniel Golle wrote: > On Sat, Nov 25, 2023 at 08:28:20AM +0000, Russell King (Oracle) wrote: > > On Sat, Nov 25, 2023 at 04:56:20AM +0000, Daniel Golle wrote: > > > Assume 'usxgmii' being set as initial interface mode in DTS. Now plug > > > a 2.5GBase-T SFP module with exposed PHY. Currently this results in > > > a rather bizare situation: > > > > > > RTL8221B-VB-CG 2.5Gbps PHY (C45) i2c:sfp1-wan:11: rtl822x_c45_get_features: supported=00,00000000,00008000,000080ef > > > mtk_soc_eth 15100000.ethernet eth2: requesting link mode phy/2500base-x with support 00,00000000,00008000,0000e0ef > > > mtk_soc_eth 15100000.ethernet eth2: switched to phy/2500base-x link mode <<< !!!!!! > > > mtk_soc_eth 15100000.ethernet eth2: major config usxgmii <<< !!!!!! > > > mtk_soc_eth 15100000.ethernet eth2: phylink_mac_config: mode=phy/usxgmii/none adv=00,00000000,00000000,00000000 pause=00 > > > mtk_soc_eth 15100000.ethernet eth2: PHY [i2c:sfp1-wan:11] driver [RTL8221B-VB-CG 2.5Gbps PHY (C45)] (irq=POLL) > > > mtk_soc_eth 15100000.ethernet eth2: phy: 2500base-x setting supported 00,00000000,00008000,0000e0ef advertising 00,00000000,00008000,0000e0ef > > > > > > Then the link seemingly comes up (but is dead) because no subsequent > > > call to phylink_major_config actually configured MAC and PCS for > > > 2500base-x mode. > > > > > > This is because phylink_mac_initial_config() considers > > > pl->phy_state.interface if in MLO_AN_PHY mode while > > > phylink_sfp_set_config() only sets pl->link_config.interface. > > > > > > Also set pl->phy_state.interface in phylink_sfp_set_config(). > > > > Does it _actually_ matter? > > It does matter, I'm suggesting this change because the SFP module > won't work without it. > > > When the PHY's link comes up, doesn't it get sorted out for the real > > mode that will be used? > > That does happen once the interface mode *changes* to anything else, > than 2500M/Full and the PHY driver sets state->interface to SGMII. > However, initially it does *not* happen, probably because phylink > ends up believing MAC and PCS are already operating in 2500base-x > mode (but that's not the case). > > Previously (eg. with the BananaPi R3) this has not been a problem > because the default interface mode defined in device tree anyway has > also been 2500base-x. Now that I'm testing the same module with the > R4 which uses usxgmii by default the problem surfaced. Okay, I think what we have here is an ordering issue in phylink_sfp_connect_phy(). phylink_bringup_phy() will set phy_state.interface, but that happens after the major config has happened. With a built-in PHY, the sequence would be: - connect to PHY (which calls phylink_bringup_phy()) - phylink_start() (which calls phylink_major_config()) whereas in this case we have the reverse. That needs to be sorted. I can't do that over this weekend, but if you remind me I'll look at it next week. Thanks.
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c index aa842634d5c2c..21ef77e4fe720 100644 --- a/drivers/net/phy/phylink.c +++ b/drivers/net/phy/phylink.c @@ -3056,6 +3056,7 @@ static void phylink_sfp_set_config(struct phylink *pl, u8 mode, pl->link_config.interface != state->interface) { pl->cur_link_an_mode = mode; pl->link_config.interface = state->interface; + pl->phy_state.interface = state->interface; changed = true;
Assume 'usxgmii' being set as initial interface mode in DTS. Now plug a 2.5GBase-T SFP module with exposed PHY. Currently this results in a rather bizare situation: RTL8221B-VB-CG 2.5Gbps PHY (C45) i2c:sfp1-wan:11: rtl822x_c45_get_features: supported=00,00000000,00008000,000080ef mtk_soc_eth 15100000.ethernet eth2: requesting link mode phy/2500base-x with support 00,00000000,00008000,0000e0ef mtk_soc_eth 15100000.ethernet eth2: switched to phy/2500base-x link mode <<< !!!!!! mtk_soc_eth 15100000.ethernet eth2: major config usxgmii <<< !!!!!! mtk_soc_eth 15100000.ethernet eth2: phylink_mac_config: mode=phy/usxgmii/none adv=00,00000000,00000000,00000000 pause=00 mtk_soc_eth 15100000.ethernet eth2: PHY [i2c:sfp1-wan:11] driver [RTL8221B-VB-CG 2.5Gbps PHY (C45)] (irq=POLL) mtk_soc_eth 15100000.ethernet eth2: phy: 2500base-x setting supported 00,00000000,00008000,0000e0ef advertising 00,00000000,00008000,0000e0ef Then the link seemingly comes up (but is dead) because no subsequent call to phylink_major_config actually configured MAC and PCS for 2500base-x mode. This is because phylink_mac_initial_config() considers pl->phy_state.interface if in MLO_AN_PHY mode while phylink_sfp_set_config() only sets pl->link_config.interface. Also set pl->phy_state.interface in phylink_sfp_set_config(). Fixes: 31eb8907aa5b ("net: phylink: allow attaching phy for SFP modules on 802.3z mode") Signed-off-by: Daniel Golle <daniel@makrotopia.org> --- drivers/net/phy/phylink.c | 1 + 1 file changed, 1 insertion(+)