Re: [PATCH net v2 1/1] net: pcs: xpcs: fix incorrect CL37 AN sequence
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2021-09-29 13:13:45
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On Wed, Sep 29, 2021 at 08:05:34PM +0800, Wong Vee Khee wrote:
According to Synopsys DesignWare Cores Ethernet PCS databook, it is required to disable Clause 37 auto-negotiation by programming bit-12 (AN_ENABLE) to 0 if it is already enabled, before programming various fields of VR_MII_AN_CTRL registers. After all these programming are done, it is then required to enable Clause 37 auto-negotiation by programming bit-12 (AN_ENABLE) to 1. Cc: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: Wong Vee Khee <redacted> ---
netdev/fixes_present fail Series targets non-next tree, but doesn't contain any Fixes tags https://patchwork.kernel.org/project/netdevbpf/patch/20210929120534.411157-1-vee.khee.wong@linux.intel.com/
quoted hunk ↗ jump to hunk
v1 -> v2: - Removed use of xpcs_modify() helper function. - Add conditional check on inband auto-negotiation. drivers/net/pcs/pcs-xpcs.c | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-)diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c index fb0a83dc09ac..f34d5caeaba1 100644 --- a/drivers/net/pcs/pcs-xpcs.c +++ b/drivers/net/pcs/pcs-xpcs.c@@ -700,11 +700,14 @@ static int xpcs_config_aneg_c37_sgmii(struct dw_xpcs *xpcs, unsigned int mode) int ret; /* For AN for C37 SGMII mode, the settings are :- - * 1) VR_MII_AN_CTRL Bit(2:1)[PCS_MODE] = 10b (SGMII AN) - * 2) VR_MII_AN_CTRL Bit(3) [TX_CONFIG] = 0b (MAC side SGMII) + * 1) VR_MII_MMD_CTRL Bit(12) [AN_ENABLE] = 0b (Disable SGMII AN in case + it is already enabled) + * 2) VR_MII_AN_CTRL Bit(2:1)[PCS_MODE] = 10b (SGMII AN) + * 3) VR_MII_AN_CTRL Bit(3) [TX_CONFIG] = 0b (MAC side SGMII) * DW xPCS used with DW EQoS MAC is always MAC side SGMII. - * 3) VR_MII_DIG_CTRL1 Bit(9) [MAC_AUTO_SW] = 1b (Automatic + * 4) VR_MII_DIG_CTRL1 Bit(9) [MAC_AUTO_SW] = 1b (Automatic * speed/duplex mode change by HW after SGMII AN complete) + * 5) VR_MII_MMD_CTRL Bit(12) [AN_ENABLE] = 1b (Enable SGMII AN) * * Note: Since it is MAC side SGMII, there is no need to set * SR_MII_AN_ADV. MAC side SGMII receives AN Tx Config from@@ -712,6 +715,12 @@ static int xpcs_config_aneg_c37_sgmii(struct dw_xpcs *xpcs, unsigned int mode) * between PHY and Link Partner. There is also no need to * trigger AN restart for MAC-side SGMII. */ + ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_MMD_CTRL); + if (ret < 0) + return ret; + ret &= ~AN_CL37_EN; + xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_MMD_CTRL, ret);
For consistency can you please check the return code from this xpcs_write too?
quoted hunk ↗ jump to hunk
+ ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_AN_CTRL); if (ret < 0) return ret;@@ -736,7 +745,20 @@ static int xpcs_config_aneg_c37_sgmii(struct dw_xpcs *xpcs, unsigned int mode) else ret &= ~DW_VR_MII_DIG_CTRL1_MAC_AUTO_SW; - return xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_DIG_CTRL1, ret); + ret = xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_DIG_CTRL1, ret); + if (ret < 0) + return ret; + + ret = xpcs_read(xpcs, MDIO_MMD_VEND2, DW_VR_MII_MMD_CTRL); + if (ret < 0) + return ret; + + if (phylink_autoneg_inband(mode)) + ret |= AN_CL37_EN; + else + ret &= ~AN_CL37_EN; + + return xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_MMD_CTRL, ret);
Not sure whether this is too much for "net" or not, but I suppose it is pretty much relevant. Clearing AN_CL37_EN during the first step is only necessary if it was set in the first place. Otherwise, you could do only the xpcs_read but not the xpcs_write. At the end, you don't really need to read DW_VR_MII_MMD_CTRL again, you just read it above, didn't you, can't you save it in a local variable? And you only need to perform the write if the state of the AN_CL37_EN bit changed, i.e. it was 0 before, and is now 1. What I'm trying to say is that for the sja1105 driver, the XPCS is accessed over SPI commands, and I would like for the number of those to be minimized if possible. Thanks. I've tested the change and it still works, by the way. I will add the appropriate tags when you resend the v3.
} static int xpcs_config_2500basex(struct dw_xpcs *xpcs) -- 2.25.1