Re: [PATCH v3] libnvdimm: Update persistence domain value for of_pmem and papr_scm device

[Dan Williams <dan.j.williams@intel.com>]

On Mon, Mar 23, 2020 at 8:48 PM Aneesh Kumar K.V
<aneesh.kumar@linux.ibm.com> wrote:
>
> Currently, kernel shows the below values
>         "persistence_domain":"cpu_cache"
>         "persistence_domain":"memory_controller"
>         "persistence_domain":"unknown"
>
> "cpu_cache" indicates no extra instructions is needed to ensure the persistence
> of data in the pmem media on power failure.
>
> "memory_controller" indicates cpu cache flush instructions are required to flush
> the data. Platform provides mechanisms to automatically flush outstanding
> write data from memory controler to pmem on system power loss.
>
> Based on the above use memory_controller for non volatile regions on ppc64.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
> Changes from V1:
> * update commit message and retain ADR details in comment

Looks good to me, applied.

>
>  arch/powerpc/platforms/pseries/papr_scm.c | 4 +++-
>  drivers/nvdimm/of_pmem.c                  | 4 +++-
>  2 files changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
> index 0b4467e378e5..922a4fc3b61b 100644
> --- a/arch/powerpc/platforms/pseries/papr_scm.c
> +++ b/arch/powerpc/platforms/pseries/papr_scm.c
> @@ -361,8 +361,10 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
>
>         if (p->is_volatile)
>                 p->region = nvdimm_volatile_region_create(p->bus, &ndr_desc);
> -       else
> +       else {
> +               set_bit(ND_REGION_PERSIST_MEMCTRL, &ndr_desc.flags);
>                 p->region = nvdimm_pmem_region_create(p->bus, &ndr_desc);
> +       }
>         if (!p->region) {
>                 dev_err(dev, "Error registering region %pR from %pOF\n",
>                                 ndr_desc.res, p->dn);
> diff --git a/drivers/nvdimm/of_pmem.c b/drivers/nvdimm/of_pmem.c
> index 8224d1431ea9..6826a274a1f1 100644
> --- a/drivers/nvdimm/of_pmem.c
> +++ b/drivers/nvdimm/of_pmem.c
> @@ -62,8 +62,10 @@ static int of_pmem_region_probe(struct platform_device *pdev)
>
>                 if (is_volatile)
>                         region = nvdimm_volatile_region_create(bus, &ndr_desc);
> -               else
> +               else {
> +                       set_bit(ND_REGION_PERSIST_MEMCTRL, &ndr_desc.flags);
>                         region = nvdimm_pmem_region_create(bus, &ndr_desc);
> +               }
>
>                 if (!region)
>                         dev_warn(&pdev->dev, "Unable to register region %pR from %pOF\n",
> --
> 2.25.1
>
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