Messages in this thread | | | Date | Tue, 15 Nov 2022 14:17:02 +0100 | From | Robert Richter <> | Subject | Re: [PATCH v3 4/9] cxl/mem: Skip intermediate port enumeration of restricted endpoints (RCDs) |
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On 14.11.22 16:07:58, Dan Williams wrote: > Robert Richter wrote: > > When an endpoint is found, all ports in beetween the endpoint and the > > CXL host bridge need to be created. In the RCH case there are no ports > > in between a host bridge and the endpoint. Skip the enumeration of > > intermediate ports. > > > > The port enumeration does not only create all ports, it also > > initializes the endpoint chain by adding the endpoint to every > > downstream port up to the root bridge. This must be done also in RCD > > mode, but is much more simple as the endpoint only needs to be added > > to the host bridge's dport. > > > > Note: For endpoint removal the cxl_detach_ep() is not needed as it is > > released in cxl_port_release(). > > > > Signed-off-by: Robert Richter <rrichter@amd.com> > > --- > > drivers/cxl/core/port.c | 18 ++++++++++++++++-- > > 1 file changed, 16 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c > > index d10c3580719b..e21a9c3fe4da 100644 > > --- a/drivers/cxl/core/port.c > > +++ b/drivers/cxl/core/port.c > > @@ -1366,8 +1366,24 @@ int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd) > > { > > struct device *dev = &cxlmd->dev; > > struct device *iter; > > + struct cxl_dport *dport; > > + struct cxl_port *port; > > int rc; > > > > + /* > > + * Skip intermediate port enumeration in the RCH case, there > > + * are no ports in between a host bridge and an endpoint. Only > > + * initialize the EP chain. > > + */ > > + if (is_cxl_restricted(cxlmd)) { > > I changed this to: > > if (cxlmd->cxlds->rcd) {
I a mail to Bjorn I suggested to have cxl_dev_cap and a cxl_port_cap in the pci_dev struct that could be looked up too including RCD mode. Checking the pci_dev looks more reasonable to me here, though we could have a flag of it in cxlds too.
-Robert
> > ...where the cxl_pci driver sets that rcd flag. Aside from keeping some > PCI specifics out of this helper it also allows RCH/RCD configurations > to be mocked with cxl_test. > > > + port = cxl_mem_find_port(cxlmd, &dport); > > + if (!port) > > + return -ENXIO; > > + rc = cxl_add_ep(dport, &cxlmd->dev); > > Ah, good catch, I had missed this detail previously. > > > + put_device(&port->dev); > > + return rc; > > + } > > + > > rc = devm_add_action_or_reset(&cxlmd->dev, cxl_detach_ep, cxlmd); > > if (rc) > > return rc; > > @@ -1381,8 +1397,6 @@ int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd) > > for (iter = dev; iter; iter = grandparent(iter)) { > > struct device *dport_dev = grandparent(iter); > > struct device *uport_dev; > > - struct cxl_dport *dport; > > - struct cxl_port *port; > > > > if (!dport_dev) > > return 0; > > -- > > 2.30.2 > > > >
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