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.
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..
> + * @next: cxl switch port across the link attached to @dport NULL if
> + * attached to an endpoint
> */
> struct cxl_ep {
> struct device *ep;
> struct cxl_dport *dport;
> + struct cxl_port *next;
> };
>
> /*
> @@ -398,6 +401,8 @@ struct pci_bus *cxl_port_to_pci_bus(struct cxl_port *port);
> struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
> resource_size_t component_reg_phys,
> struct cxl_dport *parent_dport);
> +int devm_cxl_add_endpoint(struct cxl_memdev *cxlmd,
> + struct cxl_dport *parent_dport);
> struct cxl_port *find_cxl_root(struct device *dev);
> int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd);
> int cxl_bus_rescan(void);
> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
> index 2786d3402c9e..64ccf053d32c 100644
> --- a/drivers/cxl/mem.c
> +++ b/drivers/cxl/mem.c
> @@ -25,34 +25,6 @@
> * in higher level operations.
> */
>
> -static int create_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;
> - int rc;
> -
> - 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;
> -}
> -
> static void enable_suspend(void *data)
> {
> cxl_mem_active_dec();
> @@ -116,7 +88,7 @@ static int cxl_mem_probe(struct device *dev)
> goto unlock;
> }
>
> - rc = create_endpoint(cxlmd, dport);
> + rc = devm_cxl_add_endpoint(cxlmd, dport);
> unlock:
> device_unlock(&parent_port->dev);
> put_device(&parent_port->dev);
