[PATCH] kernel: Mediatek: fix EEE registers init

[Daniel Golle]

Hi Qingfang,

I've been testing EEE support on MT7986 as well as MT7988 with your
patches on top of OpenWrt's Linux 6.6.82.

I noticed that while the LPI timer of the MT753x DSA switch ports is
30us by default it is deplayed as 0us on the SoC's Ethernet ports, which
seems wrong... I guess this should be fixed as well.


Cheers

Daniel


On Wed, Mar 12, 2025 at 10:40:55PM +0800, Qingfang Deng wrote:
> Hi Jonas,
> 
> Due to major API changes upstream, the feature wasn't backported as-is.
> https://web.git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=952d7325362ffbefa6ce5619fb4e53c2159ec7a7
> 
> The original commit does not need fixes.
> 
> Regards,
> Qingfang
> 
> [Resent as plaintext mode]
> 
> 
> On Wed, Mar 12, 2025 at 10:21 PM Jonas Gorski <jonas.gorski at gmail.com> wrote:
> >
> > Hi,
> >
> > On Sat, Mar 8, 2025 at 7:01 PM Qingfang Deng <dqfext at gmail.com> wrote:
> > >
> > > After booting, a "transmit queue 0 timed out" warning followed by a
> > > register dump was observed. The dump indicates that mtk_hw_init() does
> > > not initialize the EEECR during probe. This occurs because the
> > > netdev is allocated in mtk_add_mac(), which is called after
> > > mtk_hw_init(). Consequently, the EEECR register remains uninitialized
> > > until a reset is triggered, causing mtk_hw_init() to run again with a
> > > valid netdev, at which point the register is finally set.
> > >
> > > To address this, instead of modifying the probe sequence, latch the Tx
> > > LPI enable state and timer value, and move the EEECR register
> > > initialization to mtk_mac_link_up() to ensure proper setup when the
> > > interface comes up.
> > >
> > > Additionally, the splat reveals that LPI functionality is controlled by
> > > the MAC_MCR_EEE bits in the MCR register. Update mtk_set_eee() to
> > > modify these bits accordingly.
> > >
> > > Fixes: d8315d5358d5 ("kernel: backport Mediatek SoC EEE support")
> > > Fixes: edddbaf79ccf ("kernel: Mediatek: set default EEE Tx LPI timer")
> > > Signed-off-by: Qingfang Deng <dqfext at gmail.com>
> > > ---
> > >  ...et-ethernet-mediatek-add-EEE-support.patch | 57 ++++++++++++-------
> > >  ..._eth_soc-add-hw-dump-for-forced-rese.patch |  4 +-
> > >  ...net-mtk_eth_soc-enable-threaded-NAPI.patch |  2 +-
> > >  ..._eth_soc-reset-all-TX-queues-on-DMA-.patch |  2 +-
> > >  ..._eth_soc-compile-out-netsys-v2-code-.patch |  4 +-
> > >  ..._eth_soc-work-around-issue-with-send.patch |  6 +-
> > >  ...ernet-mtk_eth_soc-use-napi_build_skb.patch |  4 +-
> > >  ...-mediatek-enlarge-DMA-reserve-buffer.patch |  2 +-
> > >  ..._eth_soc-fix-memory-corruption-durin.patch |  2 +-
> > >  ..._eth_soc-add-paths-and-SerDes-modes-.patch | 26 ++++-----
> > >  ...th_soc-reduce-rx-ring-size-for-older.patch | 16 +++---
> > >  ..._eth_soc-do-not-enable-page-pool-sta.patch |  4 +-
> > >  12 files changed, 71 insertions(+), 58 deletions(-)
> > >
> > > diff --git a/target/linux/generic/backport-6.6/753-v6.15-net-ethernet-mediatek-add-EEE-support.patch b/target/linux/generic/backport-6.6/753-v6.15-net-ethernet-mediatek-add-EEE-support.patch
> > > index d9b86ae36e..b908d133b5 100644
> > > --- a/target/linux/generic/backport-6.6/753-v6.15-net-ethernet-mediatek-add-EEE-support.patch
> > > +++ b/target/linux/generic/backport-6.6/753-v6.15-net-ethernet-mediatek-add-EEE-support.patch
> > > @@ -23,34 +23,23 @@ Signed-off-by: Qingfang Deng <dqfext at gmail.com>
> > >                  MAC_MCR_FORCE_DPX | MAC_MCR_FORCE_TX_FC |
> > >                  MAC_MCR_FORCE_RX_FC);
> > >
> > > -@@ -811,6 +812,18 @@ static void mtk_mac_link_up(struct phyli
> > > +@@ -811,6 +812,15 @@ static void mtk_mac_link_up(struct phyli
> > >         if (rx_pause)
> > >                 mcr |= MAC_MCR_FORCE_RX_FC;
> > >
> > > -+      if (mode == MLO_AN_PHY && phy && phy_init_eee(phy, false) >= 0) {
> > > -+              switch (speed) {
> > > -+              case SPEED_2500:
> > > -+              case SPEED_1000:
> > > -+                      mcr |= MAC_MCR_EEE1G;
> > > -+                      break;
> > > -+              case SPEED_100:
> > > -+                      mcr |= MAC_MCR_EEE100M;
> > > -+                      break;
> > > -+              }
> > > ++      if (mode == MLO_AN_PHY && phy && mac->tx_lpi_enabled && phy_init_eee(phy, false) >= 0) {
> > > ++              mcr |= MAC_MCR_EEE100M | MAC_MCR_EEE1G;
> > > ++              mtk_w32(mac->hw,
> > > ++                      FIELD_PREP(MAC_EEE_WAKEUP_TIME_1000, 17) |
> > > ++                      FIELD_PREP(MAC_EEE_WAKEUP_TIME_100, 36) |
> > > ++                      FIELD_PREP(MAC_EEE_LPI_TXIDLE_THD, mac->txidle_thd_ms),
> > > ++                      MTK_MAC_EEECR(mac->id));
> > >  +      }
> > >  +
> >
> > Please don't modify backported patches, they represent upstream
> > accepted changes, so they are immutable in that regard (apart from
> > required changes for adapting them to older kernels).
> >
> > Just add a patch on top that fixes the behavior, and ideally also send
> > it  upstream to netdev so it gets proper review etc.
> >
> > Best Regards,
> > Jonas
> 
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