[Skiboot] [PATCH] npu2-opencapi: don't fence on masked XSL errors

[Andrew Donnellan]

On 12/12/19 4:07 am, Frederic Barrat wrote:
> An upcoming change in the initfile is going to modify the default
> action and fence behavior of some of the NPU FIR2 bits. We're already
> overriding the settings of most of those. The one exception is for
> bits 41 and 42, which are XSL errors impacting 2 links that we
> mask (instead we rely on the subsequent OTL error, which is per link).
> 
> The new initfile will fence-on-error for bits 41 and 42. And even if
> the FIRs are masked, the NPU logic could fence the links, which is not
> what we want. So this patch makes sure we don't fence on the FIRs we
> want to ignore. It has no effect on existing firmware.
> 
> Signed-off-by: Frederic Barrat <fbarrat at linux.ibm.com>

Reviewed-by: Andrew Donnellan <ajd at linux.ibm.com>

> ---
>   hw/npu2-opencapi.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/hw/npu2-opencapi.c b/hw/npu2-opencapi.c
> index ed6650f4..3b8b5976 100644
> --- a/hw/npu2-opencapi.c
> +++ b/hw/npu2-opencapi.c
> @@ -1681,6 +1681,7 @@ static int enable_interrupts(struct npu2 *p)
>   	reg = npu2_scom_read(p->chip_id, p->xscom_base, NPU2_MISC_FENCE_ENABLE2,
>   			     NPU2_MISC_DA_LEN_8B);
>   	reg |= xstop_override;
> +	reg &= ~(PPC_BIT(41) | PPC_BIT(42));

We do define macros for these bits which might be more explanatory. A 
comment might also be helpful...

>   	npu2_scom_write(p->chip_id, p->xscom_base, NPU2_MISC_FENCE_ENABLE2,
>   			NPU2_MISC_DA_LEN_8B, reg);
>   
> 

-- 
Andrew Donnellan              OzLabs, ADL Canberra
ajd at linux.ibm.com             IBM Australia Limited