Re: [RFC PATCH 2/2] powerpc/powernv/cpufreq: Don't assume chip id is same as Linux node id

[Gautham R Shenoy <ego@linux.vnet.ibm.com>]

On Fri, Jul 31, 2020 at 04:52:05PM +0530, Aneesh Kumar K.V wrote:
> On PowerNV platforms we always have 1:1 mapping between chip ID and
> firmware group id. Use the helper to convert firmware group id to
> node id instead of directly using chip ID as Linux node id.
> 
> NOTE: This doesn't have any functional change. On PowerNV platforms
> we continue to have 1:1 mapping between firmware group id and
> Linux node id.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
>  drivers/cpufreq/powernv-cpufreq.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
> index 8646eb197cd9..ca82b6ac0989 100644
> --- a/drivers/cpufreq/powernv-cpufreq.c
> +++ b/drivers/cpufreq/powernv-cpufreq.c
> @@ -27,6 +27,7 @@
>  #include <asm/reg.h>
>  #include <asm/smp.h> /* Required for cpu_sibling_mask() in UP configs */
>  #include <asm/opal.h>
> +#include <asm/topology.h>
>  #include <linux/timer.h>
> 
>  #define POWERNV_MAX_PSTATES_ORDER  8
> @@ -1069,8 +1070,14 @@ static int init_chip_info(void)
>  	}
> 
>  	for (i = 0; i < nr_chips; i++) {
> +		unsigned int nid;
> +
>  		chips[i].id = chip[i];
> -		cpumask_copy(&chips[i].mask, cpumask_of_node(chip[i]));
> +		/*
> +		 * On powervn platforms firmware group id is same as chipd id.

But doesn't hurt to be safe :-)

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>

> +		 */
> +		nid = firmware_group_id_to_nid(chip[i]);
> +		cpumask_copy(&chips[i].mask, cpumask_of_node(nid));
>  		INIT_WORK(&chips[i].throttle, powernv_cpufreq_work_fn);
>  		for_each_cpu(cpu, &chips[i].mask)
>  			per_cpu(chip_info, cpu) =  &chips[i];
> -- 
> 2.26.2
>