RE: [RFC/PATCH 05/18] ravb: Exclude gPTP feature support for RZ/G2L

From: Biju Das <biju.das.jz@bp.renesas.com>
To: Biju Das <biju.das.jz@bp.renesas.com>,
	Sergey Shtylyov <s.shtylyov@omp.ru>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Andrew Lunn <andrew@lunn.ch>,
	Sergei Shtylyov <sergei.shtylyov@gmail.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Adam Ford <aford173@gmail.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Biju Das <biju.das@bp.renesas.com>
Subject: RE: [RFC/PATCH 05/18] ravb: Exclude gPTP feature support for RZ/G2L
Date: Sun, 26 Sep 2021 13:48:43 +0000	[thread overview]
Message-ID: <OS0PR01MB5922FA566A26F50382F789F286A69@OS0PR01MB5922.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <OS0PR01MB5922FCB43284B938A4E12D1686A39@OS0PR01MB5922.jpnprd01.prod.outlook.com>

Hi Sergei,

> Subject: RE: [RFC/PATCH 05/18] ravb: Exclude gPTP feature support for
> RZ/G2L
> 
> Hi Sergei,
> 
> > Subject: Re: [RFC/PATCH 05/18] ravb: Exclude gPTP feature support for
> > RZ/G2L
> >
> > On 9/23/21 10:13 PM, Biju Das wrote:
> >
> > [...]
> > >>> R-Car supports gPTP feature whereas RZ/G2L does not support it.
> > >>> This patch excludes gtp feature support for RZ/G2L by enabling
> > >>> no_gptp feature bit.
> > >>>
> > >>> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > >>> ---
> > >>>  drivers/net/ethernet/renesas/ravb_main.c | 46
> > >>> ++++++++++++++----------
> > >>>  1 file changed, 28 insertions(+), 18 deletions(-)
> > >>>
> > >>> diff --git a/drivers/net/ethernet/renesas/ravb_main.c
> > >>> b/drivers/net/ethernet/renesas/ravb_main.c
> > >>> index d38fc33a8e93..8663d83507a0 100644
> > >>> --- a/drivers/net/ethernet/renesas/ravb_main.c
> > >>> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> > >> [...]
> > >>> @@ -953,7 +954,7 @@ static irqreturn_t ravb_interrupt(int irq,
> > >>> void
> > >> *dev_id)
> > >>>  	}
> > >>>
> > >>>  	/* gPTP interrupt status summary */
> > >>> -	if (iss & ISS_CGIS) {
> > >>
> > >>    Isn't this bit always 0 on RZ/G2L?
> > >
> > > This CGIM bit(BIT13) which is present on R-Car Gen3 is not present
> > > in RZ/G2L. As per the HW manual
> > > BIT13 is reserved bit and read is always 0.

> > >
> > >>
> > >>> +	if (!info->no_gptp && (iss & ISS_CGIS)) {
> >
> >    Then extending this check doesn't seem necessary?

I have dropped this check in new version.

> >
> > >>>  		ravb_ptp_interrupt(ndev);
> > >>>  		result = IRQ_HANDLED;
> > >>>  	}
> > [...]
> > >>> @@ -2116,6 +2119,7 @@ static const struct ravb_hw_info
> > >>> rgeth_hw_info =
> > {
> > >>>  	.emac_init = ravb_rgeth_emac_init,
> > >>>  	.aligned_tx = 1,
> > >>>  	.tx_counters = 1,
> > >>> +	.no_gptp = 1,
> > >>
> > >>    Mhm, I definitely don't like the way you "extend" the GbEthernet
> > >> info structure. All the applicable flags should be set in the last
> > >> patch of the series, not amidst of it.
> > >
> > > According to me, It is clearer with smaller patches like, what we
> > > have
> > done with previous 2 patch sets for factorisation.
> > > Please correct me, if any one have different opinion.
> >
> >    I'm afraid you'd get a partly functioning device with the RZ/G2
> > info introduced amidst of the series and then the necessary
> > flags/values added to it. This should definitely be avoided.
> 
> It is ok, It is understood, After replacing all  the place holders only we
> get full functionality.
> That is the reason place holders added in first patch, so that we can fill
> each function at later stage By smaller patcher. Same case for feature
> bits.
> 

OK, the new patch excluded gPTP support for RZ/G2L and Also as per your suggestion,dropped timestamp feature bit and merged that code in this patch.

Regards,
Biju