Re: [PATCH] riscv: Fix SiFive E CLINT clock frequency

[Alistair Francis]

On Fri, Nov 17, 2023 at 6:31 PM Román Cárdenas <rcardenas.rod@gmail.com> wrote:
>
> If you check the manual of SiFive E310 
> (https://cdn.sparkfun.com/assets/7/f/0/2/7/fe310-g002-manual-v19p05.pdf),
> you can see in Figure 1 that the CLINT is connected to the real time clock, 
> which also feeds the AON peripheral (they share the same clock).
> In page 43, the docs also say that the timer registers of the CLINT count 
> ticks from the rtcclk.
>
> I am currently playing with bare metal applications both in QEMU and a 
> physical SiFive E310 board and
> I confirm that the CLINT clock in the physical board runs at 32.768 kHz.
> In QEMU, the same app produces a completely different outcome, as sometimes a 
> new CLINT interrupt is triggered before finishing other tasks.
>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1978
>
> Signed-off-by: Román Cárdenas <rcardenas.rod@gmail.com>

Thanks!

Applied to riscv-to-apply.next

Alistair

> ---
>  hw/riscv/sifive_e.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/riscv/sifive_e.c b/hw/riscv/sifive_e.c
> index 0d37adc542..87d9602383 100644
> --- a/hw/riscv/sifive_e.c
> +++ b/hw/riscv/sifive_e.c
> @@ -225,7 +225,7 @@ static void sifive_e_soc_realize(DeviceState *dev, Error 
> **errp)
>              RISCV_ACLINT_SWI_SIZE,
>          RISCV_ACLINT_DEFAULT_MTIMER_SIZE, 0, ms->smp.cpus,
>          RISCV_ACLINT_DEFAULT_MTIMECMP, RISCV_ACLINT_DEFAULT_MTIME,
> -        RISCV_ACLINT_DEFAULT_TIMEBASE_FREQ, false);
> +        SIFIVE_E_LFCLK_DEFAULT_FREQ, false);
>      sifive_e_prci_create(memmap[SIFIVE_E_DEV_PRCI].base);
>
>      /* AON */
> --
> 2.39.3 (Apple Git-145)
>
>