RE: [PATCH v4 2/5] tty: serial: sh-sci: Fix Rx on RZ/G2L SCI

From: Biju Das <biju.das.jz@bp.renesas.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	Yoshinori Sato <ysato@users.sourceforge.jp>,
	"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: RE: [PATCH v4 2/5] tty: serial: sh-sci: Fix Rx on RZ/G2L SCI
Date: Wed, 29 Mar 2023 09:31:53 +0000	[thread overview]
Message-ID: <OS0PR01MB59229C03DC95C34B755C2C2986899@OS0PR01MB5922.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <ZCQCxQDwR1N4KT4r@kroah.com>

Hi Greg,

> Subject: Re: [PATCH v4 2/5] tty: serial: sh-sci: Fix Rx on RZ/G2L SCI
> 
> On Wed, Mar 29, 2023 at 09:06:43AM +0000, Biju Das wrote:
> > Hi Greg,
> >
> > Thanks for the feedback.
> >
> > > Subject: Re: [PATCH v4 2/5] tty: serial: sh-sci: Fix Rx on RZ/G2L
> > > SCI
> > >
> > > On Tue, Mar 28, 2023 at 11:32:38AM +0000, Biju Das wrote:
> > > > Hi Geert,
> > > >
> > > > Thanks for the feedback.
> > > >
> > > > > Subject: Re: [PATCH v4 2/5] tty: serial: sh-sci: Fix Rx on
> > > > > RZ/G2L SCI
> > > > >
> > > > > On Tue, Mar 21, 2023 at 12:48 PM Biju Das
> > > > > <biju.das.jz@bp.renesas.com>
> > > > > wrote:
> > > > > > SCI IP on RZ/G2L alike SoCs do not need regshift compared to
> > > > > > other SCI IPs on the SH platform. Currently, it does regshift
> > > > > > and configuring Rx wrongly. Drop adding regshift for RZ/G2L alike
> SoCs.
> > > > > >
> > > > > > Fixes: dfc80387aefb ("serial: sh-sci: Compute the regshift
> > > > > > value for SCI ports")
> > > > > > Cc: stable@vger.kernel.org
> > > > > > Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > > > > > ---
> > > > > > v3->v4:
> > > > > >  * Updated the fixes tag
> > > > > >  * Replaced sci_port->is_rz_sci with dev->dev.of_node as
> > > > > > regshift are only
> > > > > needed
> > > > > >    for sh770x/sh7750/sh7760, which don't use DT yet.
> > > > > >  * Dropped is_rz_sci variable from struct sci_port.
> > > > >
> > > > > Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> > > > >
> > > > > One can wonder how this ever worked on DT-based H8/300...
> > > >
> > > > Yep, it is interesting to see whether SCI ever worked on DT-based
> > > > H8/300 Assuming it has same register layout as RZ/G2L SoC.
> > >
> > > This is already in Linus's tree now, right?
> >
> > As per the discussion with Geert, It is been removed since 2022. Yes, It
> is present in backports.
> >
> > Geert, please correct me If I am wrong.
> 
> Seems to not apply against 6.3-rc3 :(

OK, Only H8/300 support is removed in 2022. But we have RZ/G2L alike SoCs that
needs this fix. SCI support for RZ/G2L SoCs in DT[1] are present since 5.17 +.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/arch/arm64/boot/dts/renesas/r9a07g044.dtsi?h=linux-5.17.y#n393

Cheers,
Biju