On Fri, 2016-02-12 at 11:41 -0800, Dan Williams wrote:
> On Tue, Feb 2, 2016 at 10:55 AM, Toshi Kani <toshi.kani@xxxxxxx> wrote:
> > Change acpi_nfit_register_region() to call iomem_set_desc() with
> > IORES_DESC_PERSISTENT_MEMORY for NFIT_SPA_PM ranges found in ACPI
> > NFIT table.
> >
> > When FW sets E820_PMEM in e820 and EFI_PERSISTENT_MEMORY in EFI,
> > this code simply sets PMEM type again to "Persistent Memory" entries
> > in the iomem table. When FW sets reserved type for persistent
> > memory ranges, it sets PMEM type to "reserved" entries covering
> > PMEM ranges.
> >
> > This allows the EINJ driver, which calls region_intersects() with
> > IORES_DESC_PERSISTENT_MEMORY to check persistent memory ranges,
> > to work continuously even if FW sets reserved type to persistent
> > memory in e820 and EFI.
> >
> > Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
> > Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> > Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> > Cc: Borislav Petkov <bp@xxxxxxx>
> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/acpi/nfit.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
> > index ad6d8c6..add04f0 100644
> > --- a/drivers/acpi/nfit.c
> > +++ b/drivers/acpi/nfit.c
> > @@ -1781,6 +1781,12 @@ static int acpi_nfit_register_region(struct
> > acpi_nfit_desc *acpi_desc,
> >
> > nvdimm_bus = acpi_desc->nvdimm_bus;
> > if (nfit_spa_type(spa) == NFIT_SPA_PM) {
> > + rc = iomem_set_desc(spa->address, spa->length,
> > + IORES_DESC_PERSISTENT_MEMORY);
> > + if (rc)
> > + dev_dbg(acpi_desc->dev,
> > + "error setting iomem desc: %d\n", rc);
> > +
>
> Hmm, if we set the type on driver load, should we clear the type on
> driver unload?
I think this type update should stay for the life-cycle of this iomem entry
itself since this range is PMEM even after the driver is unloaded. This is
an extension of the boot-time iomem table initialization from e820/EFI,
which allows ACPI to set a correct type. This is independent from driver's
resource allocations.
> Actually it might be more straightforward to specify a type at
> request_region() time. That way it gets released at release_region().
> We're already setting a resource name at request_region time, adding a
> type annotation at the time seems appropriate.
I first considered simply setting "namespaceX.X" as PMEM. However,
region_intersects() and its friends only check the top-level entries, not
their children, of the iomem table. And I think a child should have the
same type as the parent as I fixed it in patch 1/3.
Thanks,
-Toshi
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