target/linux/generic/backport-5.15/733-v6.3-16-net-ethernet-mtk_eth_soc-only-write-values-if-needed.patch

   1 From 6e933a804c7db8be64f367f33e63cd7dcc302ebb Mon Sep 17 00:00:00 2001
   2 From: Daniel Golle <daniel@makrotopia.org>
   3 Date: Tue, 14 Mar 2023 00:34:45 +0000
   4 Subject: [PATCH 2/2] net: ethernet: mtk_eth_soc: only write values if needed
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Only restart auto-negotiation and write link timer if actually
  10 necessary. This prevents losing the link in case of minor
  11 changes.
  12
  13 Fixes: 7e538372694b ("net: ethernet: mediatek: Re-add support SGMII")
  14 Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
  15 Tested-by: Bjørn Mork <bjorn@mork.no>
  16 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  17 Signed-off-by: David S. Miller <davem@davemloft.net>
  18 ---
  19  drivers/net/ethernet/mediatek/mtk_sgmii.c | 24 +++++++++++------------
  20  1 file changed, 12 insertions(+), 12 deletions(-)
  21
  22 --- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
  23 +++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
  24 @@ -38,20 +38,16 @@ static int mtk_pcs_config(struct phylink
  25                           const unsigned long *advertising,
  26                           bool permit_pause_to_mac)
  27  {
  28 +       bool mode_changed = false, changed, use_an;
  29         struct mtk_pcs *mpcs = pcs_to_mtk_pcs(pcs);
  30         unsigned int rgc3, sgm_mode, bmcr;
  31         int advertise, link_timer;
  32 -       bool changed, use_an;
  33
  34         advertise = phylink_mii_c22_pcs_encode_advertisement(interface,
  35                                                              advertising);
  36         if (advertise < 0)
  37                 return advertise;
  38
  39 -       link_timer = phylink_get_link_timer_ns(interface);
  40 -       if (link_timer < 0)
  41 -               return link_timer;
  42 -
  43         /* Clearing IF_MODE_BIT0 switches the PCS to BASE-X mode, and
  44          * we assume that fixes it's speed at bitrate = line rate (in
  45          * other words, 1000Mbps or 2500Mbps).
  46 @@ -77,13 +73,16 @@ static int mtk_pcs_config(struct phylink
  47         }
  48
  49         if (use_an) {
  50 -               /* FIXME: Do we need to set AN_RESTART here? */
  51 -               bmcr = SGMII_AN_RESTART | SGMII_AN_ENABLE;
  52 +               bmcr = SGMII_AN_ENABLE;
  53         } else {
  54                 bmcr = 0;
  55         }
  56
  57         if (mpcs->interface != interface) {
  58 +               link_timer = phylink_get_link_timer_ns(interface);
  59 +               if (link_timer < 0)
  60 +                       return link_timer;
  61 +
  62                 /* PHYA power down */
  63                 regmap_update_bits(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL,
  64                                    SGMII_PHYA_PWD, SGMII_PHYA_PWD);
  65 @@ -101,16 +100,17 @@ static int mtk_pcs_config(struct phylink
  66                 regmap_update_bits(mpcs->regmap, mpcs->ana_rgc3,
  67                                    RG_PHY_SPEED_3_125G, rgc3);
  68
  69 +               /* Setup the link timer */
  70 +               regmap_write(mpcs->regmap, SGMSYS_PCS_LINK_TIMER, link_timer / 2 / 8);
  71 +
  72                 mpcs->interface = interface;
  73 +               mode_changed = true;
  74         }
  75
  76         /* Update the advertisement, noting whether it has changed */
  77         regmap_update_bits_check(mpcs->regmap, SGMSYS_PCS_ADVERTISE,
  78                                  SGMII_ADVERTISE, advertise, &changed);
  79
  80 -       /* Setup the link timer and QPHY power up inside SGMIISYS */
  81 -       regmap_write(mpcs->regmap, SGMSYS_PCS_LINK_TIMER, link_timer / 2 / 8);
  82 -
  83         /* Update the sgmsys mode register */
  84         regmap_update_bits(mpcs->regmap, SGMSYS_SGMII_MODE,
  85                            SGMII_REMOTE_FAULT_DIS | SGMII_SPEED_DUPLEX_AN |
  86 @@ -118,7 +118,7 @@ static int mtk_pcs_config(struct phylink
  87
  88         /* Update the BMCR */
  89         regmap_update_bits(mpcs->regmap, SGMSYS_PCS_CONTROL_1,
  90 -                          SGMII_AN_RESTART | SGMII_AN_ENABLE, bmcr);
  91 +                          SGMII_AN_ENABLE, bmcr);
  92
  93         /* Release PHYA power down state
  94          * Only removing bit SGMII_PHYA_PWD isn't enough.
  95 @@ -132,7 +132,7 @@ static int mtk_pcs_config(struct phylink
  96         usleep_range(50, 100);
  97         regmap_write(mpcs->regmap, SGMSYS_QPHY_PWR_STATE_CTRL, 0);
  98
  99 -       return changed;
 100 +       return changed || mode_changed;
 101  }
 102
 103  static void mtk_pcs_restart_an(struct phylink_pcs *pcs)