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

[René van Dorst]

Hi Russel and Sean,

Quoting Russell King - ARM Linux admin <li...@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+ker...@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



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