Hi Biju,
CC linux-sh
On Fri, Mar 17, 2023 at 10:15 AM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > Subject: Re: [PATCH] tty: serial: sh-sci: Fix transmit end interrupt handler
> > On Fri, Mar 17, 2023 at 9:08 AM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > > Subject: Re: [PATCH] tty: serial: sh-sci: Fix transmit end interrupt
> > > > handler On Fri, Mar 17, 2023 at 8:59 AM Biju Das
> > <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > > > > Subject: Re: [PATCH] tty: serial: sh-sci: Fix transmit end
> > > > > > interrupt handler On Thu, Mar 16, 2023 at 5:34 PM Biju Das
> > > > <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > > > > > > Subject: Re: [PATCH] tty: serial: sh-sci: Fix transmit end
> > > > > > > > interrupt handler
> > > > > >
> > > > > > > > On Thu, Mar 16, 2023 at 5:01 PM Biju Das
> > > > > > > > <biju.das.jz@xxxxxxxxxxxxxx>
> > > > > > wrote:
> > > > > > > > > The RZ SCI/ RZ/A1 SCIF has only 4 interrupts. The fourth
> > > > > > > > > interrupt is transmit end interrupt, so shuffle the
> > > > > > > > > interrupts to fix the transmit end interrupt handler for these
> > IPs.
> > > > > > > > >
> > > > > > > > > Fixes: 392fb8df528b ("serial: sh-sci: Use
> > > > > > > > > platform_get_irq_optional() for optional interrupts")
> > > > > > > >
> > > > > > > > I don't think that's the right bad commit.
> > > > > > >
> > > > > > > OK. I will use below commit as fixes one, that is the commit
> > > > > > > which added RZ/A1 SCIF with 4 interrupts.
> > > > > > >
> > > > > > > commit 8b0bbd956228ae87 ("serial: sh-sci: Add support for
> > > > > > > R7S9210")
> > > > > >
> > > > > > That one added support for RZ/A2, and is also not the bad commit?
> > > > >
> > > > > OK will use below one,
> > > > >
> > > > > Fixes: 4c84c1b3acca ("ARM: shmobile: r7s72100: add scif nodes to
> > > > > dtsi")
> > > >
> > > > This really starts to look like a guessing game... Beep ;-)
> > >
> > > Already there is a generic compatible in driver, where we started
> > > introducing RZ/A1 SoC With 4 interrupts. So addition of this SoC has this
> > issue. Am I missing anything here?
> >
> > The rabbit hole seems to be deeper than I thought...
> >
> > Looking at the code, the driver always assumed the fourth interrupt is BRI,
> > which matches the RZ/A1 datasheet for SCIF.
> > So the 4 IRQ case is really a subset of the 6 IRQ case, and
> > Documentation/devicetree/bindings/serial/renesas,scif.yaml
> > is wrong.
>
> OK.
>
> >
> > However, SCI(g) is the odd one (also on SH): it has TEI as the fourth IRQ,
> > which I probably missed when doing the json-schema conversion in commit
> > 384d00fae8e51f8f ("dt-bindings: serial: sh-sci: Convert to json-schema"),
> > leading to the bug in scif.yaml.
> >
> > Note that the driver never looks at the interrupt names, but uses indices
> > exclusively.
> >
> > So I guess SCI has been broken on SH since forever, too?
>
> I think so, by looking at the changes done in tx to make it work on RZ/G2UL.
> On RZ/G2UL both rx and tx is broken.
>
> Not sure SCI is tested ever on SH platform??
>
> Can any SH platform person confirm this?
SCI is only supported on
- sh770x,
- sh7750 (excluding rts7751r2d)
I know it's not exposed on my landisk,
- sh7760, for the SIM-port, which I doubt anyone uses.
FTR, I tried the "obvious" thing (remove the rts7751r2d-checks in
arch/sh/kernel/cpu/sh4/setup-sh7750.c, and replace sci_br_interrupt
as the interrupt handler by sci_tx_interrupt in sh-sci.c), but that
didn't make ttySC0 work on qemu/rts7751r2d.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
