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

[Choong Yong Liang <yong.liang.choong@linux.intel.com>]

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@linux.intel.com>
>>
>> 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@linux.intel.com>
>> Signed-off-by: Choong Yong Liang <yong.liang.choong@linux.intel.com>
>> ---
>>   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.