Re: [PATCH net-next v3 2/5] net: pcs: xpcs: combine C37 SGMII AN and 2500BASEX for Intel mGbE controller

From: Choong Yong Liang
Date: Mon Jan 29 2024 - 08:16:15 EST




On 26/9/2023 6:51 pm, Serge Semin wrote:
Hi Choong

On Thu, Sep 21, 2023 at 08:19:43PM +0800, Choong Yong Liang wrote:
From: "Tan, Tee Min" <tee.min.tan@xxxxxxxxxxxxxxx>

This commit introduces xpcs_sgmii_2500basex_features[] that combine
xpcs_sgmii_features[] and xpcs_2500basex_features[] for Intel mGbE
controller that desire to interchange the speed mode of
10/100/1000/2500Mbps at runtime.

Also, we introduce xpcs_config_aneg_c37_sgmii_2500basex() function
which is called by the xpcs_do_config() with the new AN mode:
DW_SGMII_2500BASEX, and this new function will proceed next-level
calling to perform C37 SGMII AN/2500BASEX configuration based on
the PHY interface updated by PHY driver.

Why do you even need all of those changes? Please thoroughly justify
because ... (see below)


Signed-off-by: Tan, Tee Min <tee.min.tan@xxxxxxxxxxxxxxx>
Signed-off-by: Choong Yong Liang <yong.liang.choong@xxxxxxxxxxxxxxx>
---
drivers/net/pcs/pcs-xpcs.c | 72 ++++++++++++++++++++++++++++++------
include/linux/pcs/pcs-xpcs.h | 1 +
2 files changed, 62 insertions(+), 11 deletions(-)

diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c
index 4dbc21f604f2..60d90191677d 100644
--- a/drivers/net/pcs/pcs-xpcs.c
+++ b/drivers/net/pcs/pcs-xpcs.c
@@ -104,6 +104,21 @@ static const int xpcs_2500basex_features[] = {
__ETHTOOL_LINK_MODE_MASK_NBITS,
};

+static const int xpcs_sgmii_2500basex_features[] = {
+ ETHTOOL_LINK_MODE_Pause_BIT,
+ ETHTOOL_LINK_MODE_Asym_Pause_BIT,
+ ETHTOOL_LINK_MODE_Autoneg_BIT,
+ ETHTOOL_LINK_MODE_10baseT_Half_BIT,
+ ETHTOOL_LINK_MODE_10baseT_Full_BIT,
+ ETHTOOL_LINK_MODE_100baseT_Half_BIT,
+ ETHTOOL_LINK_MODE_100baseT_Full_BIT,
+ ETHTOOL_LINK_MODE_1000baseT_Half_BIT,
+ ETHTOOL_LINK_MODE_1000baseT_Full_BIT,
+ ETHTOOL_LINK_MODE_2500baseX_Full_BIT,
+ ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
+ __ETHTOOL_LINK_MODE_MASK_NBITS,
+};
+
static const phy_interface_t xpcs_usxgmii_interfaces[] = {
PHY_INTERFACE_MODE_USXGMII,
};
@@ -133,6 +148,12 @@ static const phy_interface_t xpcs_2500basex_interfaces[] = {
PHY_INTERFACE_MODE_MAX,
};
+static const phy_interface_t xpcs_sgmii_2500basex_interfaces[] = {
+ PHY_INTERFACE_MODE_SGMII,
+ PHY_INTERFACE_MODE_2500BASEX,
+ PHY_INTERFACE_MODE_MAX,
+};
+

... these are just a combination of the
xpcs_sgmii_features[]/xpcs_sgmii_interfaces[] and
xpcs_2500basex_features[]/xpcs_2500basex_interfaces[] data which are
already supported by the generic DW XPCS code. All of these features
and interfaces are checked in the xpcs_create() method and then get to
be combined in the framework of the xpcs_validate() and
xpcs_get_interfaces() functions. And ...

enum {
DW_XPCS_USXGMII,
DW_XPCS_10GKR,
@@ -141,6 +162,7 @@ enum {
DW_XPCS_SGMII,
DW_XPCS_1000BASEX,
DW_XPCS_2500BASEX,
+ DW_XPCS_SGMII_2500BASEX,
DW_XPCS_INTERFACE_MAX,
};
@@ -290,6 +312,7 @@ static int xpcs_soft_reset(struct dw_xpcs *xpcs,
case DW_AN_C37_SGMII:
case DW_2500BASEX:
case DW_AN_C37_1000BASEX:
+ case DW_SGMII_2500BASEX:
dev = MDIO_MMD_VEND2;
break;
default:
@@ -748,6 +771,8 @@ static int xpcs_config_aneg_c37_sgmii(struct dw_xpcs *xpcs,
if (xpcs->dev_flag == DW_DEV_TXGBE)
ret |= DW_VR_MII_DIG_CTRL1_PHY_MODE_CTRL;

+ /* Disable 2.5G GMII for SGMII C37 mode */
+ ret &= ~DW_VR_MII_DIG_CTRL1_2G5_EN;

* This is the only specific change in this patch. But it can be
* applied independently from the rest of the changes. Although I agree
* with Russel, it must be double checked since may cause regressions
* on the other platforms.

ret = xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_DIG_CTRL1, ret);
if (ret < 0)
return ret;
@@ -848,6 +873,26 @@ static int xpcs_config_2500basex(struct dw_xpcs *xpcs)
return xpcs_write(xpcs, MDIO_MMD_VEND2, DW_VR_MII_MMD_CTRL, ret);
}

+static int xpcs_config_aneg_c37_sgmii_2500basex(struct dw_xpcs *xpcs,
+ unsigned int neg_mode,
+ phy_interface_t interface)
+{
+ int ret = -EOPNOTSUPP;
+
+ switch (interface) {
+ case PHY_INTERFACE_MODE_SGMII:
+ ret = xpcs_config_aneg_c37_sgmii(xpcs, neg_mode);
+ break;
+ case PHY_INTERFACE_MODE_2500BASEX:
+ ret = xpcs_config_2500basex(xpcs);
+ break;
+ default:
+ break;
+ }
+
+ return ret;
+}
+

... this is just a copy of the code which is already available in xpcs_do_config():

< compat = xpcs_find_compat(xpcs->id, interface);
< if (!compat)
< return -ENODEV;
<
< switch (compat->an_mode) {
< ...
< case DW_AN_C37_SGMII:
< ret = xpcs_config_aneg_c37_sgmii(xpcs, neg_mode);
< if (ret)
< return ret;
< break;
< ...
< case DW_2500BASEX:
< ret = xpcs_config_2500basex(xpcs);
< if (ret)
< return ret;
< break;

So based on the passed interface xpcs_find_compat() will find a proper
compat descriptor, which an_mode field will be then utilized to call
the respective config method. Thus, unless I miss something, basically
you won't need any of the changes below and the most of the changes
above reducing the patch to just a few lines.

-Serge(y)

int xpcs_do_config(struct dw_xpcs *xpcs, phy_interface_t interface,
const unsigned long *advertising, unsigned int neg_mode)
{
@@ -890,6 +935,12 @@ int xpcs_do_config(struct dw_xpcs *xpcs, phy_interface_t interface,
if (ret)
return ret;
break;
+ case DW_SGMII_2500BASEX:
+ ret = xpcs_config_aneg_c37_sgmii_2500basex(xpcs, neg_mode,
+ interface);
+ if (ret)
+ return ret;
+ break;
default:
return -1;
}
@@ -1114,6 +1165,11 @@ static void xpcs_get_state(struct phylink_pcs *pcs,
}
break;
case DW_AN_C37_SGMII:
+ case DW_SGMII_2500BASEX:
+ /* 2500BASEX is not supported for in-band AN mode. */
+ if (state->interface == PHY_INTERFACE_MODE_2500BASEX)
+ break;
+
ret = xpcs_get_state_c37_sgmii(xpcs, state);
if (ret) {
pr_err("xpcs_get_state_c37_sgmii returned %pe\n",
@@ -1266,23 +1322,17 @@ static const struct xpcs_compat synopsys_xpcs_compat[DW_XPCS_INTERFACE_MAX] = {
.num_interfaces = ARRAY_SIZE(xpcs_10gbaser_interfaces),
.an_mode = DW_10GBASER,
},
- [DW_XPCS_SGMII] = {
- .supported = xpcs_sgmii_features,
- .interface = xpcs_sgmii_interfaces,
- .num_interfaces = ARRAY_SIZE(xpcs_sgmii_interfaces),
- .an_mode = DW_AN_C37_SGMII,
- },
[DW_XPCS_1000BASEX] = {
.supported = xpcs_1000basex_features,
.interface = xpcs_1000basex_interfaces,
.num_interfaces = ARRAY_SIZE(xpcs_1000basex_interfaces),
.an_mode = DW_AN_C37_1000BASEX,
},
- [DW_XPCS_2500BASEX] = {
- .supported = xpcs_2500basex_features,
- .interface = xpcs_2500basex_interfaces,
- .num_interfaces = ARRAY_SIZE(xpcs_2500basex_interfaces),
- .an_mode = DW_2500BASEX,
+ [DW_XPCS_SGMII_2500BASEX] = {
+ .supported = xpcs_sgmii_2500basex_features,
+ .interface = xpcs_sgmii_2500basex_interfaces,
+ .num_interfaces = ARRAY_SIZE(xpcs_sgmii_2500basex_features),
+ .an_mode = DW_SGMII_2500BASEX,
},
};
diff --git a/include/linux/pcs/pcs-xpcs.h b/include/linux/pcs/pcs-xpcs.h
index da3a6c30f6d2..f075d2fca54a 100644
--- a/include/linux/pcs/pcs-xpcs.h
+++ b/include/linux/pcs/pcs-xpcs.h
@@ -19,6 +19,7 @@
#define DW_2500BASEX 3
#define DW_AN_C37_1000BASEX 4
#define DW_10GBASER 5
+#define DW_SGMII_2500BASEX 6
/* device vendor OUI */
#define DW_OUI_WX 0x0018fc80
--
2.25.1


Hi Serge and Russell

This patch does not serve the purpose correctly, I did remove this patch and handle it properly in the new patch series.