Re: [PATCH v2 3/3] sh: dma: Correct the number of DMA channels in SH7709

From: Geert Uytterhoeven
Date: Tue Jul 04 2023 - 03:33:16 EST


Hi Adrian,

On Tue, Jul 4, 2023 at 7:45 AM John Paul Adrian Glaubitz
<glaubitz@xxxxxxxxxxxxxxxxxxx> wrote:
> On Sat, 2023-06-17 at 13:09 +0200, Geert Uytterhoeven wrote:
> > On Sat, Jun 17, 2023 at 9:32 AM John Paul Adrian Glaubitz
> > <glaubitz@xxxxxxxxxxxxxxxxxxx> wrote:
> > > On Thu, 2023-06-08 at 12:03 +0200, John Paul Adrian Glaubitz wrote:
> > > > > > > That is actually safer, as the user can override NR_ONCHIP_DMA_CHANNELS
> > > > > > > when configuring his kernel, thus breaking DMA due to an incorrect
> > > > > > > value of SH_DMAC_NR_MD_CH.
> > > > > > >
> > > > > > > Unfortunately we cannot protect against that when using a single DMAC,
> > > > > > > as SH_DMAC_NR_MD_CH can be either 4, 6, or 8.
> > > > > > >
> > > > > > > Perhaps this configuration should be moved from Kconfig to <cpu/dma.h>,
> > > > > > > to protect against a user overriding this value?
> > > > > >
> > > > > > Isn't SH_DMAC_NR_MD_CH already hardwired to the SoC being used?
> > > > >
> > > > > It depends on CONFIG_NR_ONCHIP_DMA_CHANNELS, while it
> > > > > should be fixed based on the SoC.
> > > >
> > > > I agree. However, I would be fine with merging this patch set first and fixing
> > > > this particular issue in a follow-up series.
> > >
> > > So, my suggestion is to take this series as-is for 6.5, then get the other issues
> > > you mentioned fixed for 6.6. I think it's already a gain when these issues are
> > > fixed and the kernel boots on the HP Journada 680 again.
> >
> > Sure, I don't want to block the acceptance of this series at all.
> > Thanks!
>
> Apologies for the late reply. Would you mind adding your Reviewed-by to this patch
> before I review and apply the series?

With "must be a multiply of two" and "Must be an even number" removed.
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

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