Re: [PATCH v2 3/3] hw/{misc, riscv}: pfsoc: add system controller as unimplemented

[Philippe Mathieu-Daudé]

Hi Conor,

On 12/11/22 14:34, Conor Dooley wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
>
> The system controller on PolarFire SoC is access via a mailbox. The
> control registers for this mailbox lie in the "IOSCB" region & the
> interrupt is cleared via write to the "SYSREG" region. It also has a
> QSPI controller, usually connected to a flash chip, that is used for
> storing FPGA bitstreams and used for In-Application Programming (IAP).
>
> Linux has an implementation of the system controller, through which the
> hwrng is accessed, leading to load/store access faults.
>
> Add the QSPI as unimplemented and a very basic (effectively
> unimplemented) version of the system controller's mailbox. Rather than
> purely marking the regions as unimplemented, service the mailbox
> requests by reporting failures and raising the interrupt so a guest can
> better handle the lack of support.
>
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>   hw/misc/mchp_pfsoc_ioscb.c          | 59 ++++++++++++++++++++++++++++-
>   hw/misc/mchp_pfsoc_sysreg.c         | 19 ++++++++--
>   hw/riscv/microchip_pfsoc.c          |  6 +++
>   include/hw/misc/mchp_pfsoc_ioscb.h  |  3 ++
>   include/hw/misc/mchp_pfsoc_sysreg.h |  1 +
>   include/hw/riscv/microchip_pfsoc.h  |  1 +
>   6 files changed, 83 insertions(+), 6 deletions(-)

> @@ -52,10 +54,18 @@ static uint64_t mchp_pfsoc_sysreg_read(void *opaque, hwaddr 
> offset,
>   static void mchp_pfsoc_sysreg_write(void *opaque, hwaddr offset,
>                                       uint64_t value, unsigned size)
>   {
> -    qemu_log_mask(LOG_UNIMP, "%s: unimplemented device write "
> -                  "(size %d, value 0x%" PRIx64
> -                  ", offset 0x%" HWADDR_PRIx ")\n",
> -                  __func__, size, value, offset);
> +    MchpPfSoCSysregState *s = opaque;
> +    qemu_irq_lower(s->irq);

Is this always lowered IRQ line wanted? ...

> +    switch (offset) {
> +    case MESSAGE_INT:
> +        qemu_irq_lower(s->irq);

... since we do it here.

> +        break;
> +    default:
> +        qemu_log_mask(LOG_UNIMP, "%s: unimplemented device write "
> +                      "(size %d, value 0x%" PRIx64
> +                      ", offset 0x%" HWADDR_PRIx ")\n",
> +                      __func__, size, value, offset);
> +    }
>   }