Jonathan Cameron wrote:
> On Thu, 23 Jun 2022 21:19:36 -0700
> Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>
> > The port scanning algorithm in devm_cxl_enumerate_ports() walks up the
> > topology and adds cxl_port objects starting from the root down to the
> > endpoint. When those ports are initially created they know all their
> > dports, but they do not know the downstream cxl_port instance that
> > represents the next descendant in the topology. Rework create_endpoint()
> > into devm_cxl_add_endpoint() that enumerates the downstream cxl_port
> > topology into each port's 'struct cxl_ep' record for each endpoint it
> > that the port is an ancestor.
> >
> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
>
> I'm doing my normal moaning about tidying up in a patch that makes
> a more serious change. Ideally pull that out, but meh if it's a real pain
> I can live with it as long as you call it out in the patch description.
No worries, I would expect to be able to ask others to do the same and I
should be more careful to collect these unrelated fixups separately.
>
> With that
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
>
> > ---
> > drivers/cxl/core/port.c | 41 +++++++++++++++++++++++++++++++++++++++++
> > drivers/cxl/cxl.h | 7 ++++++-
> > drivers/cxl/mem.c | 30 +-----------------------------
> > 3 files changed, 48 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> > index 08a380d20cf1..2e56903399c2 100644
> > --- a/drivers/cxl/core/port.c
> > +++ b/drivers/cxl/core/port.c
> > @@ -1089,6 +1089,47 @@ static struct cxl_ep *cxl_ep_load(struct cxl_port *port,
> > return xa_load(&port->endpoints, (unsigned long)&cxlmd->dev);
> > }
> >
> > +int devm_cxl_add_endpoint(struct cxl_memdev *cxlmd,
> > + struct cxl_dport *parent_dport)
> > +{
> > + struct cxl_port *parent_port = parent_dport->port;
> > + struct cxl_dev_state *cxlds = cxlmd->cxlds;
> > + struct cxl_port *endpoint, *iter, *down;
> > + int rc;
> > +
> > + /*
> > + * Now that the path to the root is established record all the
> > + * intervening ports in the chain.
> > + */
> > + for (iter = parent_port, down = NULL; !is_cxl_root(iter);
> > + down = iter, iter = to_cxl_port(iter->dev.parent)) {
> > + struct cxl_ep *ep;
> > +
> > + ep = cxl_ep_load(iter, cxlmd);
> > + ep->next = down;
> > + }
> > +
> > + endpoint = devm_cxl_add_port(&parent_port->dev, &cxlmd->dev,
> > + cxlds->component_reg_phys, parent_dport);
> > + if (IS_ERR(endpoint))
> > + return PTR_ERR(endpoint);
> > +
> > + dev_dbg(&cxlmd->dev, "add: %s\n", dev_name(&endpoint->dev));
> > +
> > + rc = cxl_endpoint_autoremove(cxlmd, endpoint);
> > + if (rc)
> > + return rc;
> > +
> > + if (!endpoint->dev.driver) {
> > + dev_err(&cxlmd->dev, "%s failed probe\n",
> > + dev_name(&endpoint->dev));
> > + return -ENXIO;
> > + }
> > +
> > + return 0;
> > +}
> > +EXPORT_SYMBOL_NS_GPL(devm_cxl_add_endpoint, CXL);
> > +
> > static void cxl_detach_ep(void *data)
> > {
> > struct cxl_memdev *cxlmd = data;
> > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> > index 0211cf0d3574..f761cf78cc05 100644
> > --- a/drivers/cxl/cxl.h
> > +++ b/drivers/cxl/cxl.h
> > @@ -371,11 +371,14 @@ struct cxl_dport {
> > /**
> > * struct cxl_ep - track an endpoint's interest in a port
> > * @ep: device that hosts a generic CXL endpoint (expander or accelerator)
> > - * @dport: which dport routes to this endpoint on this port
> > + * @dport: which dport routes to this endpoint on @port
>
> fix is good, but shouldn't be in this patch really..
Rolled this into "[PATCH 25/46] cxl/port: Record dport in endpoint
references" where @dport was introduced.
