Re: [net PATCH] octeontx2-af: CN10KB: Fix FIFO length calculation for RPM2

[Naveen Mamindlapalli]

Hi,

> -----Original Message-----
> From: Simon Horman <horms@xxxxxxxxxx>
> Sent: Saturday, January 6, 2024 3:15 AM
> To: Naveen Mamindlapalli <naveenm@xxxxxxxxxxx>
> Cc: davem@xxxxxxxxxxxxx; kuba@xxxxxxxxxx; edumazet@xxxxxxxxxx;
> pabeni@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> Sunil Kovvuri Goutham <sgoutham@xxxxxxxxxxx>; Nithin Kumar Dabilpuram
> <ndabilpuram@xxxxxxxxxxx>
> Subject: Re: [net PATCH] octeontx2-af: CN10KB: Fix FIFO length
> calculation for RPM2
> 
> ----------------------------------------------------------------------
> On Fri, Jan 05, 2024 at 12:24:23PM +0530, Naveen Mamindlapalli wrote:
> > From: Nithin Dabilpuram <ndabilpuram@xxxxxxxxxxx>
> >
> > RPM0 and RPM1 on the CN10KB SoC have 8 LMACs each, whereas RPM2 has
> > only 4 LMACs. Similarly, the RPM0 and RPM1 have 256KB FIFO, whereas
> > RPM2 has 128KB FIFO. This patch fixes an issue with improper TX credit
> > programming for the RPM2 link.
> >
> > Signed-off-by: Nithin Dabilpuram <ndabilpuram@xxxxxxxxxxx>
> > Signed-off-by: Naveen Mamindlapalli <naveenm@xxxxxxxxxxx>
> 
> If this is a fix for a user-visible bug then it should have a Fixes tag. Else it should
> be targeted at net-next.

Sorry, I missed it. I'll include a fixes tag and send v2 patch.

> 
> Also, as a potential follow-up, it looks like this file (driver?) could benefit from use
> of GETMASK/FIELD_GET/FIELD_PREP.
> But, IMHO, there is no need to do that for this change which is in a style
> consistent with the rest of the file.

Sure, noted.

Thanks,
Naveen

> 
> > ---
> >  drivers/net/ethernet/marvell/octeontx2/af/rpm.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rpm.c
> > b/drivers/net/ethernet/marvell/octeontx2/af/rpm.c
> > index 4728ba34b0e3..76218f1cb459 100644
> > --- a/drivers/net/ethernet/marvell/octeontx2/af/rpm.c
> > +++ b/drivers/net/ethernet/marvell/octeontx2/af/rpm.c
> > @@ -506,6 +506,7 @@ u32 rpm2_get_lmac_fifo_len(void *rpmd, int lmac_id)
> >  	rpm_t *rpm = rpmd;
> >  	u8 num_lmacs;
> >  	u32 fifo_len;
> > +	u16 max_lmac;
> >
> >  	lmac_info = rpm_read(rpm, 0, RPM2_CMRX_RX_LMACS);
> >  	/* LMACs are divided into two groups and each group @@ -513,7
> > +514,11 @@ u32 rpm2_get_lmac_fifo_len(void *rpmd, int lmac_id)
> >  	 * Group0 lmac_id range {0..3}
> >  	 * Group1 lmac_id range {4..7}
> >  	 */
> > -	fifo_len = rpm->mac_ops->fifo_len / 2;
> > +	max_lmac = (rpm_read(rpm, 0, CGX_CONST) >> 24) & 0xFF;
> > +	if (max_lmac > 4)
> > +		fifo_len = rpm->mac_ops->fifo_len / 2;
> > +	else
> > +		fifo_len = rpm->mac_ops->fifo_len;
> >
> >  	if (lmac_id < 4) {
> >  		num_lmacs = hweight8(lmac_info & 0xF);
> > --
> > 2.39.0.198.ga38d39a4c5
> >