Messages in this thread |  | | From | "Ong, Boon Leong" <> | Subject | RE: [PATCH net-next 1/4] net: pcs: xpcs: add CL37 1000BASE-X AN support | Date | Mon, 25 Apr 2022 03:30:27 +0000 |
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>On Fri, Apr 22, 2022 at 03:35:02PM +0800, Ong Boon Leong wrote: >> @@ -774,6 +788,58 @@ static int xpcs_config_aneg_c37_sgmii(struct >dw_xpcs *xpcs, unsigned int mode) >> return ret; >> } >> >> +static int xpcs_config_aneg_c37_1000basex(struct dw_xpcs *xpcs, unsigned >int mode, >> + const unsigned long *advertising) >> +{ >> + int ret, mdio_ctrl; >> + >> + /* For AN for 1000BASE-X mode, the settings are :- >> + * 1) VR_MII_MMD_CTRL Bit(12) [AN_ENABLE] = 0b (Disable C37 AN in >case >> + * it is already enabled) >> + * 2) VR_MII_AN_CTRL Bit(2:1)[PCS_MODE] = 00b (1000BASE-X C37) >> + * 3) SR_MII_AN_ADV Bit(6)[FD] = 1b (Full Duplex) >> + * Note: Half Duplex is rarely used, so don't advertise. >> + * 4) VR_MII_MMD_CTRL Bit(12) [AN_ENABLE] = 1b (Enable C37 AN) > >So if this function gets called to update the advertisement - even if >there is no actual change - we go through a AN-disable..AN-enable >dance and cause the link to re-negotiate. That doesn't sound like nice >behaviour. Good feedback. Will look into this part.
> >> + */ >> + mdio_ctrl = xpcs_read(xpcs, MDIO_MMD_VEND2, >DW_VR_MII_MMD_CTRL); >> + if (mdio_ctrl < 0) >> + return mdio_ctrl; >> + >> + if (mdio_ctrl & AN_CL37_EN) { >> + ret = xpcs_write(xpcs, MDIO_MMD_VEND2, >DW_VR_MII_MMD_CTRL, >> + mdio_ctrl & ~AN_CL37_EN); >> + if (ret < 0) >> + return ret; >> + } >> + >> + ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_CTRL); >> + if (ret < 0) >> + return ret; >> + >> + ret &= ~DW_VR_MII_PCS_MODE_MASK; >> + ret = xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_CTRL, >ret); >> + if (ret < 0) >> + return ret; >> + >> + ret = xpcs_read(xpcs, MDIO_MMD_VEND2, MII_ADVERTISE); >> + ret |= ADVERTISE_1000XFULL; >> + ret = xpcs_write(xpcs, MDIO_MMD_VEND2, MII_ADVERTISE, ret); > >What if other bits are already set in the MII_ADVERTISE register? >Maybe consider using phylink_mii_c22_pcs_encode_advertisement()?
The IP supports C45 MII MMD access and not C22. Your feedback does make sense to strengthen the logics here. Thanks
> >The pcs_config() method is also supposed to return either a negative >error, 0 for no advertisement change, or positive for an advertisement >change, in which case phylink will trigger a call to pcs_an_restart(). > >> +static int xpcs_get_state_c37_1000basex(struct dw_xpcs *xpcs, >> + struct phylink_link_state *state) >> +{ >> + int lpa, adv; >> + int ret; >> + >> + ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_MMD_CTRL); >> + if (ret < 0) >> + return ret; >> + >> + if (ret & AN_CL37_EN) { >> + /* Reset link_state */ >> + state->link = false; >> + state->speed = SPEED_UNKNOWN; >> + state->duplex = DUPLEX_UNKNOWN; >> + state->pause = 0; > >Phylink guarantees that speed, duplex and pause are set to something >sensible - please remove these. The only one you probably need here >is state->link.
Thanks for the input here.
> >> + >> + lpa = xpcs_read(xpcs, MDIO_MMD_VEND2, MII_LPA); >> + if (lpa < 0 || lpa & LPA_RFAULT) >> + return false; > >This function does not return a boolean. Returning "false" is the same >as returning 0, which means "no error" but an error has occurred. Good catch.
> >> + >> + adv = xpcs_read(xpcs, MDIO_MMD_VEND2, MII_ADVERTISE); >> + if (adv < 0) >> + return false; > >Ditto. > >> + >> + if (lpa & ADVERTISE_1000XFULL && >> + adv & ADVERTISE_1000XFULL) { >> + state->speed = SPEED_1000; >> + state->duplex = DUPLEX_FULL; >> + state->link = true; >> + } >> + >> + /* Clear CL37 AN complete status */ >> + ret = xpcs_write(xpcs, MDIO_MMD_VEND2, >DW_VR_MII_AN_INTR_STS, 0); >> + } else { >> + state->link = true; >> + state->speed = SPEED_1000; >> + state->duplex = DUPLEX_FULL; >> + state->pause = 0; > >If we're in AN-disabled mode, phylink will set state->speed and >state->duplex according to the user's parameters, so there should be no >need to do it here. Thanks for the input.
> >> @@ -994,9 +1143,21 @@ void xpcs_link_up(struct phylink_pcs *pcs, >unsigned int mode, >> return xpcs_config_usxgmii(xpcs, speed); >> if (interface == PHY_INTERFACE_MODE_SGMII) >> return xpcs_link_up_sgmii(xpcs, mode, speed, duplex); >> + if (interface == PHY_INTERFACE_MODE_1000BASEX) >> + return xpcs_link_up_1000basex(xpcs, speed, duplex); >> } >> EXPORT_SYMBOL_GPL(xpcs_link_up); >> >> +static void xpcs_an_restart(struct phylink_pcs *pcs) >> +{ >> + struct dw_xpcs *xpcs = phylink_pcs_to_xpcs(pcs); >> + int ret; >> + >> + ret = xpcs_read(xpcs, MDIO_MMD_VEND2, MDIO_CTRL1); >> + ret |= BMCR_ANRESTART; >> + ret = xpcs_write(xpcs, MDIO_MMD_VEND2, MDIO_CTRL1, ret); > >If xpcs_read() returns an error, we try to write the error back to >the control register? Is that a good idea/ Thanks! I will fix this.
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