[PATCH v3 17/18] cxl: Add a dev_dbg() when a decoder was added to a port

Robert Richter
2025-02-11T09:55:24Z

Improve debugging by adding and unifying messages whenever a decoder
was added to a port. It is especially useful to get the decoder
mapping of the involved CXL host bridge or PCI device. This avoids a
complex lookup of the decoder/port/device mappings in sysfs.

Example log messages:

cxl_acpi ACPI0017:00: decoder0.0 added to root0
cxl_acpi ACPI0017:00: decoder0.1 added to root0
...
pci0000:e0: decoder1.0 added to port1
pci0000:e0: decoder1.1 added to port1
...
cxl_mem mem0: decoder5.0 added to endpoint5
cxl_mem mem0: decoder5.1 added to endpoint5

Signed-off-by: Robert Richter <rrichter@amd.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Tested-by: Gregory Price <gourry@gourry.net>
---
drivers/cxl/acpi.c | 10 +++++++++-
drivers/cxl/core/hdm.c | 3 ++-
2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index cb14829bb9be..3e75e612cbc4 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -421,7 +421,15 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,
rc = cxl_decoder_add(cxld, target_map);
if (rc)
return rc;
- return cxl_root_decoder_autoremove(dev, no_free_ptr(cxlrd));
+
+ rc = cxl_root_decoder_autoremove(dev, no_free_ptr(cxlrd));
+ if (rc)
+ return rc;
+
+ dev_dbg(root_port->dev.parent, "%s added to %s\n",
+ dev_name(&cxld->dev), dev_name(&root_port->dev));
+
+ return 0;
}

static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,
diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index d705dec1471e..467e4fef6a53 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -34,7 +34,8 @@ static int add_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
if (rc)
return rc;

- dev_dbg(&cxld->dev, "Added to port %s\n", dev_name(&port->dev));
+ dev_dbg(port->uport_dev, "%s added to %s\n",
+ dev_name(&cxld->dev), dev_name(&port->dev));

return 0;
}
--
2.39.5