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Box"</a><ul><li><a href="/lkml/2025/2/20/108">Choong Yong Liang</a></li></ul></li></ul></li></ul></li><li><a href="/lkml/2025/2/6/810">Choong Yong Liang</a><ul><li><a href="/lkml/2025/2/6/840">=?UTF-8?q?Ilpo=20J=C3=A4rvinen?=</a><ul><li><a href="/lkml/2025/2/7/594">Choong Yong Liang</a></li></ul></li></ul></li><li><a href="/lkml/2025/2/6/811">Choong Yong Liang</a><ul><li class="origin"><a href="/lkml/2025/2/7/523">"Russell King (Oracle)"</a><ul><li><a href="/lkml/2025/2/7/523">Choong Yong Liang</a><ul><li><a href="/lkml/2025/2/7/855">Andrew Lunn</a></li></ul></li><li><a href="/lkml/2025/2/20/105">Choong Yong Liang</a></li></ul></li></ul></li><li><a href="/lkml/2025/2/6/812">Choong Yong Liang</a></li><li><a href="/lkml/2025/2/6/813">Choong Yong Liang</a></li><li><a href="/lkml/2025/2/6/814">Choong Yong Liang</a></li></ul></li></ul></td><td width="32" rowspan="2" class="c" valign="top"><img src="/images/icornerl.gif" width="32" height="32" alt="/" /></td><td class="c" rowspan="2" valign="top" style="padding-top: 1em"><table><tr><td><table><tr><td class="lp">Date</td><td class="rp" itemprop="datePublished">Thu, 6 Feb 2025 15:30:33 +0000</td></tr><tr><td class="lp">From</td><td class="rp" itemprop="author">"Russell King (Oracle)" <></td></tr><tr><td class="lp">Subject</td><td class="rp" itemprop="name">Re: [PATCH net-next v7 2/7] net: pcs: xpcs: re-initiate clause 37 Auto-negotiation</td></tr></table></td><td></td></tr></table><pre itemprop="articleBody">On Thu, Feb 06, 2025 at 09:18:54PM +0800, Choong Yong Liang wrote:<br />> The xpcs_switch_interface_mode function was introduced to handle<br />> interface switching.<br />> <br />> According to the XPCS datasheet, a soft reset is required to initiate<br />> Clause 37 auto-negotiation when the XPCS switches interface modes.<br /><br />Hmm. Given that description, taking it literally, claus 37<br />auto-negotiation is 1000BASE-X, not Cisco SGMII (which isn't an IEEE<br />802.3 standard.) Are you absolutely sure that this applies to Cisco<br />SGMII?<br /><br />If the reset is required when switching to SGMII, should it be done<br />before or after configuring the XPCS for SGMII?<br /><br />Also, if the reset is required, what happens if we're already using<br />SGMII, but AN has been disabled temporarily and is then re-enabled?<br />Is a reset required?<br /><br />What about 1000BASE-X when AN is enabled or disabled and then switching<br />to SGMII?<br /><br />> +static int xpcs_switch_to_aneg_c37_sgmii(const struct dw_xpcs_compat *compat,<br />> + struct dw_xpcs *xpcs,<br />> + unsigned int neg_mode)<br />> +{<br />> + bool an_c37_enabled;<br />> + int ret, mdio_ctrl;<br />> +<br />> + if (neg_mode == PHYLINK_PCS_NEG_INBAND_ENABLED) {<br />> + mdio_ctrl = xpcs_read(xpcs, MDIO_MMD_VEND2, MII_BMCR);<br />> + if (mdio_ctrl < 0)<br />> + return mdio_ctrl;<br />> +<br />> + an_c37_enabled = mdio_ctrl & BMCR_ANENABLE;<br />> + if (!an_c37_enabled) {<br /><br />I don't think that we need "an_c37_enabled" here, I think simply:<br /><br /> if (!(mdio_ctrl & BMCR_ANENABLE)) {<br /><br />would be sufficient.<br /><br />> + //Perform soft reset to initiate C37 auto-negotiation<br />> + ret = xpcs_soft_reset(xpcs, compat);<br />> + if (ret)<br />> + return ret;<br />> + }<br />> + }<br />> + return 0;<br /><br />I'm also wondering (as above) whether this soft reset needs to happen<br />_after_ xpcs_config_aneg_c37_sgmii() has done its work - this function<br />temporarily disables AN while it's doing its work.<br /><br />I'm also wondering whether AN being disabled is really a deciding<br />factor (e.g. when switching from 1000BASE-X AN-enabled to SGMII, is a<br />reset required?)<br /><br />-- <br />RMK's Patch system: <a href="https://www.armlinux.org.uk/developer/patches/">https://www.armlinux.org.uk/developer/patches/</a><br />FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!<br /><br /></pre></td><td width="32" rowspan="2" class="c" valign="top"><img src="/images/icornerr.gif" width="32" height="32" alt="\" /></td></tr><tr><td align="right" valign="bottom"> 聽 </td></tr><tr><td align="right" valign="bottom">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerl.gif" width="32" height="32" alt="\" /></td><td class="c">聽</td><td class="c" valign="bottom" style="padding-bottom: 0px"><img src="/images/bcornerr.gif" width="32" height="32" alt="/" /></td></tr><tr><td align="right" valign="top" colspan="2"> 聽 </td><td class="lm">Last update: 2025-02-06 16:32 聽聽 [W:0.672 / U:0.119 seconds]<br />漏2003-2020 <a href="http://blog.jasper.es/"><span itemprop="editor">Jasper Spaans</span></a>|hosted at <a href="https://www.digitalocean.com/?refcode=9a8e99d24cf9">Digital Ocean</a> and my Meterkast|<a href="http://blog.jasper.es/categories.html#lkml-ref">Read the blog</a></td><td>聽</td></tr></table><script language="javascript" src="/js/styleswitcher.js" type="text/javascript"></script></body></html>