[Skiboot] [PATCH] phb4: Avoid MMIO load freeze escalation on every chip

[Vasant Hegde]

On 2/9/21 2:14 PM, Mahesh Salgaonkar wrote:
> The commit f397cc30bdf8 ("phb4: Only escalate freezes on MMIO load where
> necessary") introduced a change to restrict escalation to the chips that
> actually need it. However it missed one case which still causes the
> escalation on every chip. This affects EEH recovery to cause full
> PHB reset on some chips which is not necessary. This patch fixes that.
> Also, add a check for p9 chip in phb4_escalation_required() function.
> 
> Cc: skiboot-stable at lists.ozlabs.org
> Signed-off-by: Mahesh Salgaonkar <mahesh at linux.ibm.com>
> ---
>   hw/phb4.c |    6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/phb4.c b/hw/phb4.c
> index e7758d346b..edbcdb2179 100644
> --- a/hw/phb4.c
> +++ b/hw/phb4.c
> @@ -3590,6 +3590,10 @@ static bool phb4_escalation_required(void)
>   {
>   	uint64_t pvr = mfspr(SPR_PVR);
> 
> +	/* Only on Power9 */
> +	if (proc_gen != proc_gen_p9)
> +		return false;
> +

Do we really need this check? Below we have chip specific checks.

-Vasant