Re: [PATCH v3 4/4] hw/intc: riscv_aclint: Add reset function of ACLINT devices

[Alistair Francis]

On Tue, Apr 19, 2022 at 7:29 PM <frank.chang@sifive.com> wrote:
>
> From: Jim Shu <jim.shu@sifive.com>
>
> This commit implements reset function of all ACLINT devices.
> ACLINT device reset will clear MTIME and MSIP register to 0.
>
> Depend on RISC-V ACLINT spec v1.0-rc4:
> https://github.com/riscv/riscv-aclint/blob/v1.0-rc4/riscv-aclint.adoc
>
> Signed-off-by: Jim Shu <jim.shu@sifive.com>
> Reviewed-by: Frank Chang <frank.chang@sifive.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  hw/intc/riscv_aclint.c | 39 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>
> diff --git a/hw/intc/riscv_aclint.c b/hw/intc/riscv_aclint.c
> index ad7ccf96cd..67a07bb5b9 100644
> --- a/hw/intc/riscv_aclint.c
> +++ b/hw/intc/riscv_aclint.c
> @@ -293,11 +293,29 @@ static void riscv_aclint_mtimer_realize(DeviceState 
> *dev, Error **errp)
>      }
>  }
>
> +static void riscv_aclint_mtimer_reset_enter(Object *obj, ResetType type)
> +{
> +    /*
> +     * According to RISC-V ACLINT spec:
> +     *   - On MTIMER device reset, the MTIME register is cleared to zero.
> +     *   - On MTIMER device reset, the MTIMECMP registers are in unknown 
> state.
> +     */
> +    RISCVAclintMTimerState *mtimer = RISCV_ACLINT_MTIMER(obj);
> +
> +    /*
> +     * Clear mtime register by writing to 0 it.
> +     * Pending mtime interrupts will also be cleared at the same time.
> +     */
> +    riscv_aclint_mtimer_write(mtimer, mtimer->time_base, 0, 8);
> +}
> +
>  static void riscv_aclint_mtimer_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
>      dc->realize = riscv_aclint_mtimer_realize;
>      device_class_set_props(dc, riscv_aclint_mtimer_properties);
> +    ResettableClass *rc = RESETTABLE_CLASS(klass);
> +    rc->phases.enter = riscv_aclint_mtimer_reset_enter;
>  }
>
>  static const TypeInfo riscv_aclint_mtimer_info = {
> @@ -452,11 +470,32 @@ static void riscv_aclint_swi_realize(DeviceState *dev, 
> Error **errp)
>      }
>  }
>
> +static void riscv_aclint_swi_reset_enter(Object *obj, ResetType type)
> +{
> +    /*
> +     * According to RISC-V ACLINT spec:
> +     *   - On MSWI device reset, each MSIP register is cleared to zero.
> +     *
> +     * p.s. SSWI device reset does nothing since SETSIP register always 
> reads 0.
> +     */
> +    RISCVAclintSwiState *swi = RISCV_ACLINT_SWI(obj);
> +    int i;
> +
> +    if (!swi->sswi) {
> +        for (i = 0; i < swi->num_harts; i++) {
> +            /* Clear MSIP registers by lowering software interrupts. */
> +            qemu_irq_lower(swi->soft_irqs[i]);
> +        }
> +    }
> +}
> +
>  static void riscv_aclint_swi_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
>      dc->realize = riscv_aclint_swi_realize;
>      device_class_set_props(dc, riscv_aclint_swi_properties);
> +    ResettableClass *rc = RESETTABLE_CLASS(klass);
> +    rc->phases.enter = riscv_aclint_swi_reset_enter;
>  }
>
>  static const TypeInfo riscv_aclint_swi_info = {
> --
> 2.35.1
>
>