Re: [PATCH v2 03/13] hw/arm/npcm7xx_boards: Replace drive_get_next() by drive_get()

[Hao Wu <wuhaotsh@google.com>]

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Yes, there's SD and MMC buses. It looks like the current code only supports
mmc ("soc->mmc.sdhci") but not the sd ("soc->sd.sdhci").

It's probably good to make the bus number a parameter as well and use them
to distinguish. We might need a separate patch to do that.

On Wed, Nov 17, 2021 at 8:54 AM Havard Skinnemoen <hskinnemoen@google.com>
wrote:

> On Wed, Nov 17, 2021 at 8:34 AM Markus Armbruster <armbru@redhat.com>
> wrote:
> >
> > drive_get_next() is basically a bad idea.  It returns the "next" block
> > backend of a certain interface type.  "Next" means bus=0,unit=N, where
> > subsequent calls count N up from zero, per interface type.
> >
> > This lets you define unit numbers implicitly by execution order.  If the
> > order changes, or new calls appear "in the middle", unit numbers change.
> > ABI break.  Hard to spot in review.
> >
> > Machine "quanta-gbs-bmc" connects just one backend with
> > drive_get_next(), but with a helper function.  Change it to use
> > drive_get() directly.  This makes the unit numbers explicit in the
> > code.
> >
> > Cc: Havard Skinnemoen <hskinnemoen@google.com>
> > Cc: Tyrone Ting <kfting@nuvoton.com>
> > Cc: Peter Maydell <peter.maydell@linaro.org>
> > Cc: qemu-arm@nongnu.org
> > Signed-off-by: Markus Armbruster <armbru@redhat.com>
> > ---
> >  hw/arm/npcm7xx_boards.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/hw/arm/npcm7xx_boards.c b/hw/arm/npcm7xx_boards.c
> > index dec7d16ae5..d8a49e4e85 100644
> > --- a/hw/arm/npcm7xx_boards.c
> > +++ b/hw/arm/npcm7xx_boards.c
> > @@ -84,9 +84,9 @@ static void npcm7xx_connect_dram(NPCM7xxState *soc,
> MemoryRegion *dram)
> >                               &error_abort);
> >  }
> >
> > -static void sdhci_attach_drive(SDHCIState *sdhci)
> > +static void sdhci_attach_drive(SDHCIState *sdhci, int unit)
> >  {
> > -        DriveInfo *di = drive_get_next(IF_SD);
> > +        DriveInfo *di = drive_get(IF_SD, 0, unit);
>
> +Hao Wu IIRC the chip has separate SD and eMMC buses. Would it make
> sense to take the bus number as a parameter as well? Is bus 0 the
> right one to use in this case?
>
> The existing code always uses bus 0, so this is an improvement either way.
>
> Reviewed-by: Havard Skinnemoen <hskinnemoen@google.com>
>
> >          BlockBackend *blk = di ? blk_by_legacy_dinfo(di) : NULL;
> >
> >          BusState *bus = qdev_get_child_bus(DEVICE(sdhci), "sd-bus");
> > @@ -374,7 +374,7 @@ static void quanta_gbs_init(MachineState *machine)
> >                            drive_get(IF_MTD, 0, 0));
> >
> >      quanta_gbs_i2c_init(soc);
> > -    sdhci_attach_drive(&soc->mmc.sdhci);
> > +    sdhci_attach_drive(&soc->mmc.sdhci, 0);
> >      npcm7xx_load_kernel(machine, soc);
> >  }
> >
> > --
> > 2.31.1
> >
>

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