Re: [Qemu-devel] [PATCH v3 3/7] hw/arm: make bitbanded IO optional on ARM M Profile

[Peter Maydell]

On 25 July 2018 at 09:59, Stefan Hajnoczi <address@hidden> wrote:
> Some ARM CPUs have bitbanded IO, a memory region that allows convenient
> bit access via 32-bit memory loads/stores.  This eliminates the need for
> read-modify-update instruction sequences.
>
> This patch makes this optional feature a ARMMProfile qdev property,
> allowing boards to choose whether they want bitbanding or not.
>
> Status of boards:
>  * iotkit (Cortex M33), no bitband
>  * mps2 (Cortex M3), bitband
>  * msf2 (Cortex M3), bitband
>  * stellaris (Cortex M3), bitband
>  * stm32f205 (Cortex M3), bitband
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>

This fixes a bug in the MPS2 boards, incidentally, where the
Ethernet controller is inaccessible because it's hidden by
the shouldn't-be-present bitbanding region...

thanks
-- PMM