From 5fb1b8a1630115f3aa3cd6bb7bc9ba5122867f66 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Sun, 23 Jan 2022 16:54:39 -0800
Subject: [PATCH 118/217] cxl/list: Use 'physical_node' for root port
attachment detection
Platform firmware objects like ACPI0016 link from /sys/bus/acpi to
/sys/bus/pci via a 'physical_node' attribute. Consider that link when
attempting to link memdevs to root ports.
Emit it in the the target listing as the 'alias' for the listed target
device.
Link: https://lore.kernel.org/r/164298567943.3021641.12696733268157328279.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
Documentation/cxl/lib/libcxl.txt | 6 ++++++
cxl/json.c | 8 ++++++++
cxl/lib/libcxl.c | 16 +++++++++++++++-
cxl/lib/libcxl.sym | 1 +
cxl/lib/private.h | 1 +
cxl/libcxl.h | 1 +
6 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/Documentation/cxl/lib/libcxl.txt b/Documentation/cxl/lib/libcxl.txt
index bd92fef..a68a58b 100644
--- a/Documentation/cxl/lib/libcxl.txt
+++ b/Documentation/cxl/lib/libcxl.txt
@@ -389,6 +389,7 @@ unsigned long cxl_target_get_id(struct cxl_target *target);
const char *cxl_target_get_devname(struct cxl_target *target);
bool cxl_target_maps_memdev(struct cxl_target *target,
struct cxl_memdev *memdev);
+const char *cxl_target_get_physical_node(struct cxl_target *target);
----
The position of a decoder along with the interleave granularity dictate
which address in the decoder's resource range map to which port.
@@ -410,6 +411,11 @@ The cxl_target_maps_memdev() helper is the companion of
cxl_decoder_get_target_by_memdev() to determine which downstream ports /
targets are capable of mapping which memdevs.
+Some platform firmware implementations define an alias / companion
+device to represent the root of a PCI device hierarchy. The
+cxl_target_get_physical_node() helper returns the device name of that
+companion object in the PCI hierarchy.
+
include::../../copyright.txt[]
SEE ALSO
diff --git a/cxl/json.c b/cxl/json.c
index 3a37909..d81aed8 100644
--- a/cxl/json.c
+++ b/cxl/json.c
@@ -342,6 +342,7 @@ struct json_object *util_cxl_decoder_to_json(struct cxl_decoder *decoder,
cxl_target_foreach(decoder, target) {
struct json_object *jtarget = json_object_new_object();
+ const char *phys_node;
if (!jtarget)
continue;
@@ -351,6 +352,13 @@ struct json_object *util_cxl_decoder_to_json(struct cxl_decoder *decoder,
if (jobj)
json_object_object_add(jtarget, "target", jobj);
+ phys_node = cxl_target_get_physical_node(target);
+ if (phys_node) {
+ jobj = json_object_new_string(phys_node);
+ if (jobj)
+ json_object_object_add(jtarget, "alias", jobj);
+ }
+
val = cxl_target_get_position(target);
jobj = json_object_new_int(val);
if (jobj)
diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c
index 877f42c..7bf7949 100644
--- a/cxl/lib/libcxl.c
+++ b/cxl/lib/libcxl.c
@@ -72,6 +72,7 @@ static void free_target(struct cxl_target *target, struct list_head *head)
if (head)
list_del_from(head, &target->list);
free(target->dev_path);
+ free(target->phys_path);
free(target);
}
@@ -970,7 +971,11 @@ static void *add_cxl_decoder(void *parent, int id, const char *cxldecoder_base)
free(target);
break;
}
- dbg(ctx, "%s: target%ld %s\n", devname, i, target->dev_path);
+ sprintf(port->dev_buf, "%s/dport%d/physical_node", port->dev_path, did);
+ target->phys_path = realpath(port->dev_buf, NULL);
+ dbg(ctx, "%s: target%ld %s phys_path: %s\n", devname, i,
+ target->dev_path,
+ target->phys_path ? target->phys_path : "none");
list_add(&decoder->targets, &target->list);
}
@@ -1138,9 +1143,18 @@ CXL_EXPORT bool cxl_target_maps_memdev(struct cxl_target *target,
dbg(ctx, "memdev: %s target: %s\n", memdev->host_path,
target->dev_path);
+ if (target->phys_path)
+ return !!strstr(memdev->host_path, target->phys_path);
return !!strstr(memdev->host_path, target->dev_path);
}
+CXL_EXPORT const char *cxl_target_get_physical_node(struct cxl_target *target)
+{
+ if (!target->phys_path)
+ return NULL;
+ return devpath_to_devname(target->phys_path);
+}
+
CXL_EXPORT struct cxl_target *
cxl_decoder_get_target_by_memdev(struct cxl_decoder *decoder,
struct cxl_memdev *memdev)
diff --git a/cxl/lib/libcxl.sym b/cxl/lib/libcxl.sym
index cb33180..ce01298 100644
--- a/cxl/lib/libcxl.sym
+++ b/cxl/lib/libcxl.sym
@@ -141,4 +141,5 @@ global:
cxl_target_get_id;
cxl_target_get_devname;
cxl_target_maps_memdev;
+ cxl_target_get_physical_node;
} LIBCXL_1;
diff --git a/cxl/lib/private.h b/cxl/lib/private.h
index 1743a24..7e7742d 100644
--- a/cxl/lib/private.h
+++ b/cxl/lib/private.h
@@ -77,6 +77,7 @@ struct cxl_target {
struct list_node list;
struct cxl_decoder *decoder;
char *dev_path;
+ char *phys_path;
int id, position;
};
diff --git a/cxl/libcxl.h b/cxl/libcxl.h
index abda0e5..0e484cc 100644
--- a/cxl/libcxl.h
+++ b/cxl/libcxl.h
@@ -140,6 +140,7 @@ unsigned long cxl_target_get_id(struct cxl_target *target);
const char *cxl_target_get_devname(struct cxl_target *target);
bool cxl_target_maps_memdev(struct cxl_target *target,
struct cxl_memdev *memdev);
+const char *cxl_target_get_physical_node(struct cxl_target *target);
#define cxl_target_foreach(decoder, target) \
for (target = cxl_target_get_first(decoder); target != NULL; \
--
2.27.0