Jonathan Cameron wrote:
> On Sun, 05 Feb 2023 17:02:51 -0800
> Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>
> > In preparation for a new region mode, do not, for example, allow
> > 'ram' decoders to be assigned to 'pmem' regions and vice versa.
> >
> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
>
> I guess we aren't support mixed endpoint decoders for now (and
> maybe never..) If we did I'd expect this to have to allow
> mixed with either RAM or PMEM.
Mixed is a bug, or I otherwise can not think of a scenario where it is
valid. The kernel prevents it, but platform firmware can make
that mistake. I think if the kernel ever encounters that and works
around it that will come with a loud TAINT_FIRMWARE_WORKAROUND warning.
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> > ---
> > drivers/cxl/core/region.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> > index c9e7f05caa0f..53d6dbe4de6d 100644
> > --- a/drivers/cxl/core/region.c
> > +++ b/drivers/cxl/core/region.c
> > @@ -1217,6 +1217,12 @@ static int cxl_region_attach(struct cxl_region *cxlr,
> > struct cxl_dport *dport;
> > int i, rc = -ENXIO;
> >
> > + if (cxled->mode != cxlr->mode) {
> > + dev_dbg(&cxlr->dev, "%s region mode: %d mismatch: %d\n",
> > + dev_name(&cxled->cxld.dev), cxlr->mode, cxled->mode);
> > + return -EINVAL;
> > + }
> > +
> > if (cxled->mode == CXL_DECODER_DEAD) {
> > dev_dbg(&cxlr->dev, "%s dead\n", dev_name(&cxled->cxld.dev));
> > return -ENODEV;
> >
>
