Re: [PATCH RFC net-next] net: mtk_eth_soc: use resolved link config for PCS PHY

["René van Dorst" <opensource@vdorst.com>]

Hi Russel and Sean,

Quoting Russell King - ARM Linux admin <linux@armlinux.org.uk>:

> On Tue, Jun 30, 2020 at 11:15:42AM +0100, Russell King wrote:
>> The SGMII PCS PHY needs to be updated with the link configuration in
>> the mac_link_up() call rather than in mac_config().  However,
>> mtk_sgmii_setup_mode_force() programs the SGMII block during
>> mac_config() when using 802.3z interface modes with the link
>> configuration.
>>
>> Split that functionality from mtk_sgmii_setup_mode_force(), moving it
>> to a new mtk_sgmii_link_up() function, and call it from mac_link_up().
>>
>> This does not look correct to me: 802.3z modes operate at a fixed
>> speed.  The contents of mtk_sgmii_link_up() look more appropriate for
>> SGMII mode, but the original code definitely did not call
>> mtk_sgmii_setup_mode_force() for SGMII mode but only 802.3z mode.
>>
>> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
>> ---
>> René, can you assist with this patch please - I really think there are
>> problems with the existing code.  You call mtk_sgmii_setup_mode_force()
>> in a block which is conditionalised as:
>>
>> 	if (state->interface == PHY_INTERFACE_MODE_SGMII ||
>> 	    phy_interface_mode_is_8023z(state->interface)) {
>> ...
>> 		if (state->interface != PHY_INTERFACE_MODE_SGMII)
>> 			err = mtk_sgmii_setup_mode_force(eth->sgmii, sid,
>> 							 state);
>>
>> Hence, mtk_sgmii_setup_mode_force() is only called for 1000BASE-X and
>> 2500BASE-X, which do not support anything but their native speeds.
>> Yet, mtk_sgmii_setup_mode_force() tries to program the SGMII for 10M
>> and 100M.
>>
>> Note that this patch is more about moving uses of state->{speed,duplex}
>> into mac_link_up(), rather than fixing this problem, but I don't think
>> the addition in mtk_mac_link_up(), nor mtk_sgmii_link_up() is of any
>> use.
>
> My Coccinelle script just found this use of state->{speed,duplex} still
> remaining:
>
>                         if (MTK_HAS_CAPS(mac->hw->soc->caps,
>                                          MTK_TRGMII_MT7621_CLK)) {
> ...
>                         } else {
>                                 if (state->interface !=
>                                     PHY_INTERFACE_MODE_TRGMII)
>                                         mtk_gmac0_rgmii_adjust(mac->hw,
>                                                                state->speed);
>
> which also needs to be eliminated.  Can that also be moved to
> mtk_mac_link_up()?

I know, you have pointed that out before. But I don't know how to fix
mtk_gmac0_rgmii_adjust(). This function changes the PLL of the MAC.  
But without
documentation I am not sure what all the bits are used for.

Begin April I had a conversation with Sean about this. I also  
explained what the
issue was. AFAIK he was going to take care of this issue.

Sean did you had time to resolve this issue?

Greats,

René

>
> Thanks.
>
>>
>> Thanks.
>>
>>  drivers/net/ethernet/mediatek/mtk_eth_soc.c |  9 ++++-
>>  drivers/net/ethernet/mediatek/mtk_eth_soc.h |  3 +-
>>  drivers/net/ethernet/mediatek/mtk_sgmii.c   | 37 +++++++++++++++------
>>  3 files changed, 36 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c  
>> b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>> index 20db302d31ce..ef9ec3b6a5c8 100644
>> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>> @@ -326,7 +326,7 @@ static void mtk_mac_config(struct  
>> phylink_config *config, unsigned int mode,
>>  		/* Setup SGMIISYS with the determined property */
>>  		if (state->interface != PHY_INTERFACE_MODE_SGMII)
>>  			err = mtk_sgmii_setup_mode_force(eth->sgmii, sid,
>> -							 state);
>> +							 state->interface);
>>  		else if (phylink_autoneg_inband(mode))
>>  			err = mtk_sgmii_setup_mode_an(eth->sgmii, sid);
>>
>> @@ -423,6 +423,13 @@ static void mtk_mac_link_up(struct  
>> phylink_config *config,
>>  					   phylink_config);
>>  	u32 mcr = mtk_r32(mac->hw, MTK_MAC_MCR(mac->id));
>>
>> +	if (phy_interface_mode_is_8023z(interface)) {
>> +		/* Decide how GMAC and SGMIISYS be mapped */
>> +		int sid = (MTK_HAS_CAPS(eth->soc->caps, MTK_SHARED_SGMII)) ?
>> +			   0 : mac->id;
>> +		mtk_sgmii_link_up(eth->sgmii, sid, speed, duplex);
>> +	}
>> +
>>  	mcr &= ~(MAC_MCR_SPEED_100 | MAC_MCR_SPEED_1000 |
>>  		 MAC_MCR_FORCE_DPX | MAC_MCR_FORCE_TX_FC |
>>  		 MAC_MCR_FORCE_RX_FC);
>> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h  
>> b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
>> index 454cfcd465fd..6f4b99bb7bfb 100644
>> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
>> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
>> @@ -932,7 +932,8 @@ int mtk_sgmii_init(struct mtk_sgmii *ss, struct  
>> device_node *np,
>>  		   u32 ana_rgc3);
>>  int mtk_sgmii_setup_mode_an(struct mtk_sgmii *ss, int id);
>>  int mtk_sgmii_setup_mode_force(struct mtk_sgmii *ss, int id,
>> -			       const struct phylink_link_state *state);
>> +			       phy_interface_t interface);
>> +void mtk_sgmii_link_up(struct mtk_sgmii *ss, int id, int speed,  
>> int duplex);
>>  void mtk_sgmii_restart_an(struct mtk_eth *eth, int mac_id);
>>
>>  int mtk_gmac_sgmii_path_setup(struct mtk_eth *eth, int mac_id);
>> diff --git a/drivers/net/ethernet/mediatek/mtk_sgmii.c  
>> b/drivers/net/ethernet/mediatek/mtk_sgmii.c
>> index 32d83421226a..372c85c830b5 100644
>> --- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
>> +++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
>> @@ -60,7 +60,7 @@ int mtk_sgmii_setup_mode_an(struct mtk_sgmii *ss, int id)
>>  }
>>
>>  int mtk_sgmii_setup_mode_force(struct mtk_sgmii *ss, int id,
>> -			       const struct phylink_link_state *state)
>> +			       phy_interface_t interface)
>>  {
>>  	unsigned int val;
>>
>> @@ -69,7 +69,7 @@ int mtk_sgmii_setup_mode_force(struct mtk_sgmii  
>> *ss, int id,
>>
>>  	regmap_read(ss->regmap[id], ss->ana_rgc3, &val);
>>  	val &= ~RG_PHY_SPEED_MASK;
>> -	if (state->interface == PHY_INTERFACE_MODE_2500BASEX)
>> +	if (interface == PHY_INTERFACE_MODE_2500BASEX)
>>  		val |= RG_PHY_SPEED_3_125G;
>>  	regmap_write(ss->regmap[id], ss->ana_rgc3, val);
>>
>> @@ -78,11 +78,33 @@ int mtk_sgmii_setup_mode_force(struct mtk_sgmii  
>> *ss, int id,
>>  	val &= ~SGMII_AN_ENABLE;
>>  	regmap_write(ss->regmap[id], SGMSYS_PCS_CONTROL_1, val);
>>
>> +	if (interface == PHY_INTERFACE_MODE_1000BASEX ||
>> +	    interface == PHY_INTERFACE_MODE_2500BASEX) {
>> +		/* SGMII force mode setting */
>> +		regmap_read(ss->regmap[id], SGMSYS_SGMII_MODE, &val);
>> +		val &= ~SGMII_IF_MODE_MASK;
>> +		val |= SGMII_SPEED_1000;
>> +		val |= SGMII_DUPLEX_FULL;
>> +		regmap_write(ss->regmap[id], SGMSYS_SGMII_MODE, val);
>> +	}
>> +
>> +	/* Release PHYA power down state */
>> +	regmap_read(ss->regmap[id], SGMSYS_QPHY_PWR_STATE_CTRL, &val);
>> +	val &= ~SGMII_PHYA_PWD;
>> +	regmap_write(ss->regmap[id], SGMSYS_QPHY_PWR_STATE_CTRL, val);
>> +
>> +	return 0;
>> +}
>> +
>> +void mtk_sgmii_link_up(struct mtk_sgmii *ss, int id, int speed, int duplex)
>> +{
>> +	unsigned int val;
>> +
>>  	/* SGMII force mode setting */
>>  	regmap_read(ss->regmap[id], SGMSYS_SGMII_MODE, &val);
>>  	val &= ~SGMII_IF_MODE_MASK;
>>
>> -	switch (state->speed) {
>> +	switch (speed) {
>>  	case SPEED_10:
>>  		val |= SGMII_SPEED_10;
>>  		break;
>> @@ -95,17 +117,10 @@ int mtk_sgmii_setup_mode_force(struct  
>> mtk_sgmii *ss, int id,
>>  		break;
>>  	}
>>
>> -	if (state->duplex == DUPLEX_FULL)
>> +	if (duplex == DUPLEX_FULL)
>>  		val |= SGMII_DUPLEX_FULL;
>>
>>  	regmap_write(ss->regmap[id], SGMSYS_SGMII_MODE, val);
>> -
>> -	/* Release PHYA power down state */
>> -	regmap_read(ss->regmap[id], SGMSYS_QPHY_PWR_STATE_CTRL, &val);
>> -	val &= ~SGMII_PHYA_PWD;
>> -	regmap_write(ss->regmap[id], SGMSYS_QPHY_PWR_STATE_CTRL, val);
>> -
>> -	return 0;
>>  }
>>
>>  void mtk_sgmii_restart_an(struct mtk_eth *eth, int mac_id)
>> --
>> 2.20.1
>>
>>
>
> --
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!




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