RE: [EXT] Re: [net PATCH 1/5] octeontx2-af: Adjust Tx credits when MCS external bypass is disabled

[Geethasowjanya Akula]

> -----Original Message-----
> From: Wojciech Drewek <wojciech.drewek@xxxxxxxxx>
> Sent: Thursday, November 23, 2023 4:15 PM
> To: Geethasowjanya Akula <gakula@xxxxxxxxxxx>; netdev@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Cc: kuba@xxxxxxxxxx; davem@xxxxxxxxxxxxx; pabeni@xxxxxxxxxx;
> edumazet@xxxxxxxxxx; Sunil Kovvuri Goutham <sgoutham@xxxxxxxxxxx>;
> Subbaraya Sundeep Bhatta <sbhatta@xxxxxxxxxxx>; Hariprasad Kelam
> <hkelam@xxxxxxxxxxx>
> Subject: [EXT] Re: [net PATCH 1/5] octeontx2-af: Adjust Tx credits when MCS
> external bypass is disabled
> 
> External Email
> 
> ----------------------------------------------------------------------
> 
> 
> On 23.11.2023 06:59, Geetha sowjanya wrote:
> > From: Nithin Dabilpuram <ndabilpuram@xxxxxxxxxxx>
> >
> > When MCS external bypass is disabled, MCS returns additional
> > 2 credits(32B) for every packet Tx'ed on LMAC. To account for these
> > extra credits, NIX_AF_TX_LINKX_NORM_CREDIT.CC_MCS_CNT
> > needs to be configured as otherwise NIX Tx credits would overflow and
> > will never be returned to idle state credit count causing issues with
> > credit control and MTU change.
> >
> > This patch fixes the same by configuring CC_MCS_CNT at probe time for
> > MCS enabled SoC's
> >
> > Fixes: bd69476e86fc ("octeontx2-af: cn10k: mcs: Install a default TCAM
> > for normal traffic")
> > Signed-off-by: Nithin Dabilpuram <ndabilpuram@xxxxxxxxxxx>
> > Signed-off-by: Geetha sowjanya <gakula@xxxxxxxxxxx>
> > Signed-off-by: Sunil Goutham <sgoutham@xxxxxxxxxxx>
> > ---
> >  drivers/net/ethernet/marvell/octeontx2/af/mcs.c     | 12 ++++++++++++
> >  drivers/net/ethernet/marvell/octeontx2/af/mcs.h     |  2 ++
> >  drivers/net/ethernet/marvell/octeontx2/af/rvu.h     |  1 +
> >  drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c |  8 ++++++++
> >  4 files changed, 23 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/marvell/octeontx2/af/mcs.c
> > b/drivers/net/ethernet/marvell/octeontx2/af/mcs.c
> > index c43f19dfbd74..d6effbe46208 100644
> > --- a/drivers/net/ethernet/marvell/octeontx2/af/mcs.c
> > +++ b/drivers/net/ethernet/marvell/octeontx2/af/mcs.c
> > @@ -1219,6 +1219,17 @@ struct mcs *mcs_get_pdata(int mcs_id)
> >  	return NULL;
> >  }
> >
> > +bool is_mcs_bypass(int mcs_id)
> > +{
> > +	struct mcs *mcs_dev;
> > +
> > +	list_for_each_entry(mcs_dev, &mcs_list, mcs_list) {
> > +		if (mcs_dev->mcs_id == mcs_id)
> > +			return mcs_dev->bypass;
> > +	}
> > +	return true;
> 
> If there is no mcs dev with the given id it means it is bypassed?
Yes.
> 
> > +}
> > +
> >  void mcs_set_port_cfg(struct mcs *mcs, struct mcs_port_cfg_set_req
> > *req)  {
> >  	u64 val = 0;
> > @@ -1447,6 +1458,7 @@ static void mcs_set_external_bypass(struct mcs
> *mcs, u8 bypass)
> >  	else
> >  		val &= ~BIT_ULL(6);
> >  	mcs_reg_write(mcs, MCSX_MIL_GLOBAL, val);
> > +	mcs->bypass = bypass;
> >  }
> >
> >  static void mcs_global_cfg(struct mcs *mcs)
> 
> 
> <...>