Re: [net PATCH v2] octeontx2-af: Unlock contexts in the queue context cache in case of fault detection

[Sai Krishna Gajula]

Hi Simon,

> -----Original Message-----
> From: Simon Horman <simon.horman@xxxxxxxxxxxx>
> Sent: Friday, February 24, 2023 2:37 PM
> To: Sai Krishna Gajula <saikrishnag@xxxxxxxxxxx>
> Cc: davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> pabeni@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> Sunil Kovvuri Goutham <sgoutham@xxxxxxxxxxx>; Suman Ghosh
> <sumang@xxxxxxxxxxx>
> Subject: Re: [net PATCH v2] octeontx2-af: Unlock contexts in the queue
> context cache in case of fault detection
> 
> ----------------------------------------------------------------------
> On Fri, Feb 24, 2023 at 08:39:20AM +0000, Sai Krishna Gajula wrote:
> > Hi Simon,
> >
> > > -----Original Message-----
> > > From: Simon Horman <simon.horman@xxxxxxxxxxxx>
> > > Sent: Thursday, February 23, 2023 6:47 PM
> > > To: Sai Krishna Gajula <saikrishnag@xxxxxxxxxxx>
> > > Cc: davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> > > pabeni@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> > > linux-kernel@xxxxxxxxxxxxxxx; Sunil Kovvuri Goutham
> > > <sgoutham@xxxxxxxxxxx>; Suman Ghosh <sumang@xxxxxxxxxxx>
> > > Subject: Re: [net PATCH v2] octeontx2-af: Unlock contexts in the
> > > queue context cache in case of fault detection
> > >
> > >
> > > --------------------------------------------------------------------
> > > -- On Thu, Feb 23, 2023 at 04:31:25PM +0530, Sai Krishna wrote:
> > > > From: Suman Ghosh <sumang@xxxxxxxxxxx>
> > > >
> > > > NDC caches contexts of frequently used queue's (Rx and Tx queues)
> > > > contexts. Due to a HW errata when NDC detects fault/poision while
> > > > accessing contexts it could go into an illegal state where a cache
> > > > line could get locked forever. To makesure all cache lines in NDC
> > > > are available for optimum performance upon fault/lockerror/posion
> > > > errors scan through all cache lines in NDC and clear the lock bit.
> > > >
> > > > Fixes: 4a3581cd5995 ("octeontx2-af: NPA AQ instruction enqueue
> > > > support")
> > > > Signed-off-by: Suman Ghosh <sumang@xxxxxxxxxxx>
> > > > Signed-off-by: Sunil Kovvuri Goutham <sgoutham@xxxxxxxxxxx>
> > > > Signed-off-by: Sai Krishna <saikrishnag@xxxxxxxxxxx>
> > >
> > > ...
> > >
> > > > diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu.h
> > > > b/drivers/net/ethernet/marvell/octeontx2/af/rvu.h
> > > > index 389663a13d1d..6508f25b2b37 100644
> > > > --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu.h
> > > > +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu.h
> > > > @@ -884,6 +884,12 @@ int rvu_cpt_lf_teardown(struct rvu *rvu, u16
> > > > pcifunc, int blkaddr, int lf,  int rvu_cpt_ctx_flush(struct rvu
> > > > *rvu,
> > > > u16 pcifunc);  int rvu_cpt_init(struct rvu *rvu);
> > > >
> > > > +/* NDC APIs */
> > > > +#define NDC_MAX_BANK(rvu, blk_addr) (rvu_read64(rvu, \
> > > > +					blk_addr, NDC_AF_CONST) & 0xFF)
> #define
> > > > +NDC_MAX_LINE_PER_BANK(rvu, blk_addr) ((rvu_read64(rvu, \
> > > > +					blk_addr, NDC_AF_CONST) &
> > > 0xFFFF0000) >> 16)
> > >
> > > Perhaps not appropriate to include as part of a fix, as NDC_MAX_BANK
> > > is being moved from elsewhere, but I wonder if this might be more
> > > cleanly implemented using FIELD_GET().
> >
> > We will modify and send a separate patch for all the possible macros that
> can be replaced by FIELD_GET().
> 
> Thanks, much appreciated.
> 
> > > ...
> > >
> > > > diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu_reg.h
> > > > b/drivers/net/ethernet/marvell/octeontx2/af/rvu_reg.h
> > > > index 1729b22580ce..bc6ca5ccc1ff 100644
> > > > --- a/drivers/net/ethernet/marvell/octeontx2/af/rvu_reg.h
> > > > +++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu_reg.h
> > > > @@ -694,6 +694,7 @@
> > > >  #define NDC_AF_INTR_ENA_W1S		(0x00068)
> > > >  #define NDC_AF_INTR_ENA_W1C		(0x00070)
> > > >  #define NDC_AF_ACTIVE_PC		(0x00078)
> > > > +#define NDC_AF_CAMS_RD_INTERVAL		(0x00080)
> > > >  #define NDC_AF_BP_TEST_ENABLE		(0x001F8)
> > > >  #define NDC_AF_BP_TEST(a)		(0x00200 | (a) << 3)
> > > >  #define NDC_AF_BLK_RST			(0x002F0)
> > > > @@ -709,6 +710,8 @@
> > > >  		(0x00F00 | (a) << 5 | (b) << 4)
> > > >  #define NDC_AF_BANKX_HIT_PC(a)		(0x01000 | (a) << 3)
> > > >  #define NDC_AF_BANKX_MISS_PC(a)		(0x01100 | (a) << 3)
> > > > +#define NDC_AF_BANKX_LINEX_METADATA(a, b) \
> > > > +		(0x10000 | (a) << 3 | (b) << 3)
> > >
> > > It looks a little odd that both a and b are shifted by 3 bits.
> > > If it's intended then perhaps it would be clearer to write this as:
> > >
> > > #define NDC_AF_BANKX_LINEX_METADATA(a, b) \
> > > 		(0x10000 | ((a) | (b)) << 3)
> >
> > will send v3 patch.
> 
> Likewise, thanks.

We found a bug related to the macro NDC_AF_BANKX_LINEX_METADATA which we will fix and send in v3 patch.

Thanks,
Sai