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

[Havard Skinnemoen]

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
>