[PATCH] tools/testing/cxl: Resolve auto-region decoder targets like real HW

[Richard Cheng]

The mock auto-region created at module load wrote switch and host-bridge
decoder target[] directly, in addition to target_map[]. Real HW programs
only target_map[] and resolves target[] as dports enumerate, via
update_decoder_targets(). Region replay already follows that ordering,
the initial auto-region did not.

Drop the direct target[] writes and call
cxl_port_update_decoder_targets() so target[] is resolved the same way
as real HW and region replay, exercising more of the auto-region driver
path.

This is inspired by the discussion [1] below:

[1]: https://lore.kernel.org/all/20260521084806.28232-1-icheng@xxxxxxxxxx/
Suggested-by: Alison Schofield <alison.schofield@xxxxxxxxx>
Signed-off-by: Richard Cheng <icheng@xxxxxxxxxx>
---
cxl_mock_mem didn't load together when I manually modprobe cxl_test
module, should we make them loaded together automatically for better
user experience?

Best regards,
Richard Cheng.
---
 tools/testing/cxl/test/cxl.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index 418669927fb0..5266aa3733cb 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -1181,15 +1181,11 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
 		cxlsd = to_cxl_switch_decoder(dev);
 		if (i == 0) {
 			/* put cxl_mem.4 second in the decode order */
-			if (pdev->id == 4) {
-				cxlsd->target[1] = dport;
+			if (pdev->id == 4)
 				cxlsd->cxld.target_map[1] = dport->port_id;
-			} else {
-				cxlsd->target[0] = dport;
+			else
 				cxlsd->cxld.target_map[0] = dport->port_id;
-			}
 		} else {
-			cxlsd->target[0] = dport;
 			cxlsd->cxld.target_map[0] = dport->port_id;
 		}
 		cxld = &cxlsd->cxld;
@@ -1212,6 +1208,16 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
 		cxld->commit = mock_decoder_commit;
 		cxld->reset = mock_decoder_reset;
 
+		/*
+		 * Only target_map[] is programmed above, mimicking
+		 * firmware. On real hardware target[] is populated as
+		 * dports enumerate, via update_decoder_targets(). The
+		 * mock's dports are already bound by now, so fire that
+		 * resolution explicitly here rather than stamping
+		 * target[] directly.
+		 */
+		cxl_port_update_decoder_targets(iter, dport);
+
 		cxld_registry_update(cxld);
 		put_device(dev);
 	}
-- 
2.43.0