Re: [Qemu-devel] [PATCH 0/4] Disable FPU/DSP for CPU0 on musca-a and mps2-an521

[Peter Maydell]

Ping for code review, please?

thanks
-- PMM

On Fri, 17 May 2019 at 18:40, Peter Maydell <address@hidden> wrote:
>
> The SSE-200 hardware has configurable integration settings which
> determine whether its two CPUs have the FPU and DSP:
>  * CPU0_FPU (default 0)
>  * CPU0_DSP (default 0)
>  * CPU1_FPU (default 1)
>  * CPU1_DSP (default 1)
>
> Similarly, the IoTKit has settings for its single CPU:
>  * CPU0_FPU (default 1)
>  * CPU0_DSP (default 1)
>
> Of our four boards that use either the IoTKit or the SSE-200:
>  * mps2-an505, mps2-an521 and musca-a use the default settings
>  * musca-b1 enables FPU and DSP on both CPUs
>
> Currently QEMU models all these boards using CPUs with
> both FPU and DSP enabled. This means that we are incorrect
> for mps2-an521 and musca-a, which should not have FPU or DSP
> on CPU0.
>
> This patchset fixes this (fairly minor) inaccuracy by
> implementing properties on the CPU to disable the relevant
> CPU features and then wiring them up through the armv7m
> object and the ARMSSE SoC container object, so that our
> IotKit and SSE200 models behave by default the same way as
> the hardware default does, and our Musca-B1 board model
> forces the FPU/DSP to be present on CPU, as the hardware does.
>
> The 'neon' property is not strictly required for the M-profile
> issues described above, but I implemented it on the CPU
> object because disable-neon and disable-vfp interact
> for A-profile CPUs.
>
> thanks
> -- PMM
>
> Peter Maydell (4):
>   target/arm: Allow VFP and Neon to be disabled via a CPU property
>   target/arm: Allow M-profile CPUs to disable the DSP extension via CPU
>     property
>   hw/arm/armv7m: Forward "vfp" and "dsp" properties to CPU
>   hw/arm: Correctly disable FPU/DSP for some ARMSSE-based boards
>
>  include/hw/arm/armsse.h |   7 ++
>  include/hw/arm/armv7m.h |   4 +
>  target/arm/cpu.h        |   6 ++
>  hw/arm/armsse.c         |  58 ++++++++++---
>  hw/arm/armv7m.c         |  18 ++++
>  hw/arm/musca.c          |   8 ++
>  target/arm/cpu.c        | 179 ++++++++++++++++++++++++++++++++++++++--
>  7 files changed, 262 insertions(+), 18 deletions(-)
>
> --
> 2.20.1