On 15/01/26 06:28PM, Jonathan Cameron wrote:
On Fri, 9 Jan 2026 18:14:36 +0530
Neeraj Kumar <[email protected]> wrote:
create_pmem_region() creates CXL region based on region information
parsed from the Label Storage Area (LSA). This routine requires cxl
endpoint decoder and root decoder. Add cxl_find_root_decoder_by_port()
and cxl_find_free_ep_decoder() to find the root decoder and a free
endpoint decoder respectively.
Signed-off-by: Neeraj Kumar <[email protected]>
Hi Neeraj,
Just a few minor things.
Jonathan
diff --git a/drivers/cxl/core/pmem_region.c b/drivers/cxl/core/pmem_region.c
index 53d3d81e9676..4a8cf8322cf0 100644
--- a/drivers/cxl/core/pmem_region.c
+++ b/drivers/cxl/core/pmem_region.c
@@ -287,3 +287,139 @@ int devm_cxl_add_pmem_region(struct cxl_region *cxlr)
cxlr->cxl_nvb = NULL;
return rc;
}
+
+static int match_root_decoder_by_dport(struct device *dev, const void *data)
+{
+ const struct cxl_port *ep_port = data;
+ struct cxl_root_decoder *cxlrd;
+ struct cxl_port *root_port;
+ struct cxl_decoder *cxld;
+ struct cxl_dport *dport;
+ bool dport_matched = false;
+
+ if (!is_root_decoder(dev))
+ return 0;
+
+ cxld = to_cxl_decoder(dev);
+ if (!(cxld->flags & CXL_DECODER_F_PMEM))
+ return 0;
+
+ cxlrd = to_cxl_root_decoder(dev);
+
+ root_port = cxlrd_to_port(cxlrd);
+ dport = cxl_find_dport_by_dev(root_port, ep_port->host_bridge);
+ if (!dport)
+ return 0;
+
There is a fairly standard way to check if a loop matched without
needing a boolean. Just check if the exit condition was reached.
drop declaration of i out of here.
+ for (int i = 0; i < cxlrd->cxlsd.nr_targets; i++) {
+ if (dport == cxlrd->cxlsd.target[i]) {
+ dport_matched = true;
No need for this.
+ break;
+ }
+ }
+
+ if (!dport_matched)
if (i == cxlrd->cxlsd.nr_targets)
return 0;
Thanks for your suggestion. I have fixed it accordingly in V6.
+ return 0;
+
+ return is_root_decoder(dev);
+}
+
+/**
+ * cxl_find_root_decoder_by_port() - find a cxl root decoder on cxl bus
+ * @port: any descendant port in CXL port topology
+ * @cxled: endpoint decoder
+ *
+ * Caller of this function must call put_device() when done as a device ref
+ * is taken via device_find_child()
+ */
+static struct cxl_root_decoder *
+cxl_find_root_decoder_by_port(struct cxl_port *port,
+ struct cxl_endpoint_decoder *cxled)
+{
+ struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);
+ struct cxl_port *ep_port = cxled_to_port(cxled);
+ struct device *dev;
+
+ if (!cxl_root)
+ return NULL;
+
+ dev = device_find_child(&cxl_root->port.dev, ep_port,
+ match_root_decoder_by_dport);
+ if (!dev)
+ return NULL;
+
+ return to_cxl_root_decoder(dev);
+}
+void create_pmem_region(struct nvdimm *nvdimm)
+{
+ struct cxl_region *cxlr;
+ struct cxl_memdev *cxlmd;
+ struct cxl_nvdimm *cxl_nvd;
+ struct cxl_endpoint_decoder *cxled;
+ struct cxl_pmem_region_params *params;
CXL tends to be reverse xmas tree and good to stick to local style.
Changed them in reverse xmas tree style.
Regards,
Neeraj
