[PATCH 1/7] cxl/test: Refactor mock_init_hdm_decoder() to prep for type2 decoder

Dave Jiang
2026-04-22T23:02:40Z

Split mock_init_hdm_decoder() into different types of initialization.
Currently the code deals with default initialization, saved decoders,
and type3 auto region initialization. In the future, a type2 auto
initialization will also be added. This refactor will make it cleaner
to add additional init types.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
tools/testing/cxl/test/cxl.c | 184 ++++++++++++++++++++++-------------
1 file changed, 115 insertions(+), 69 deletions(-)

diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index cd47fdd7ccb5..c26c37cef12c 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -1052,74 +1052,25 @@ static int first_decoder(struct device *dev, const void *data)
return 0;
}

-/*
- * Initialize a decoder during HDM enumeration.
- *
- * If a saved registry entry exists:
- * - enabled decoders are restored from the saved programming
- * - disabled decoders are initialized in a clean disabled state
- *
- * If no registry entry exists the decoder follows the normal mock
- * initialization path, including the special auto-region setup for
- * the first endpoints under host-bridge0.
- *
- * Returns true if decoder state was restored from the registry. In
- * that case the saved decode configuration (including target mapping)
- * has already been applied and the map_targets() is skipped.
- */
-static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
+enum cxld_init_type {
+ MOCK_DECODER_INIT_DEFAULT,
+ MOCK_DECODER_INIT_SAVED,
+ MOCK_DECODER_INIT_TYPE3_AUTO,
+};
+
+static enum cxld_init_type get_decoder_init_type(struct cxl_decoder *cxld,
+ struct platform_device *pdev,
+ bool hb0,
+ struct cxl_test_decoder **td)
{
- struct acpi_cedt_cfmws *window = mock_cfmws[0];
- struct platform_device *pdev = NULL;
- struct cxl_endpoint_decoder *cxled;
- struct cxl_switch_decoder *cxlsd;
- struct cxl_port *port, *iter;
- struct cxl_test_decoder *td;
- struct cxl_memdev *cxlmd;
- struct cxl_dport *dport;
- struct device *dev;
- bool hb0 = false;
- u64 base;
- int i;
+ struct cxl_test_decoder *found_td = cxld_registry_find(cxld);

- if (is_endpoint_decoder(&cxld->dev)) {
- cxled = to_cxl_endpoint_decoder(&cxld->dev);
- cxlmd = cxled_to_memdev(cxled);
- WARN_ON(!dev_is_platform(cxlmd->dev.parent));
- pdev = to_platform_device(cxlmd->dev.parent);
-
- /* check is endpoint is attach to host-bridge0 */
- port = cxled_to_port(cxled);
- do {
- if (port->uport_dev == &cxl_host_bridge[0]->dev) {
- hb0 = true;
- break;
- }
- if (is_cxl_port(port->dev.parent))
- port = to_cxl_port(port->dev.parent);
- else
- port = NULL;
- } while (port);
- port = cxled_to_port(cxled);
- } else {
- port = to_cxl_port(cxld->dev.parent);
+ if (found_td) {
+ *td = found_td;
+ return MOCK_DECODER_INIT_SAVED;
}

- td = cxld_registry_find(cxld);
- if (td) {
- bool enabled;
-
- if (is_switch_decoder(&cxld->dev))
- enabled = td->cxlsd.cxld.flags & CXL_DECODER_F_ENABLE;
- else
- enabled = td->cxled.cxld.flags & CXL_DECODER_F_ENABLE;
-
- if (enabled)
- return !cxld_registry_restore(cxld, td);
-
- init_disabled_mock_decoder(cxld);
- return false;
- }
+ *td = NULL;

/*
* The first decoder on the first 2 devices on the first switch
@@ -1130,10 +1081,40 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
* See 'cxl list -BMPu -m cxl_mem.0,cxl_mem.4'
*/
if (!is_endpoint_decoder(&cxld->dev) || !hb0 || pdev->id % 4 ||
- pdev->id > 4 || cxld->id > 0) {
- default_mock_decoder(cxld);
- return false;
- }
+ pdev->id > 4 || cxld->id > 0)
+ return MOCK_DECODER_INIT_DEFAULT;
+
+ return MOCK_DECODER_INIT_TYPE3_AUTO;
+}
+
+static bool mock_decoder_handle_saved(struct cxl_decoder *cxld, struct cxl_test_decoder *td)
+{
+ bool enabled;
+
+ if (is_switch_decoder(&cxld->dev))
+ enabled = td->cxlsd.cxld.flags & CXL_DECODER_F_ENABLE;
+ else
+ enabled = td->cxled.cxld.flags & CXL_DECODER_F_ENABLE;
+
+ if (enabled)
+ return !cxld_registry_restore(cxld, td);
+
+ init_disabled_mock_decoder(cxld);
+ return false;
+}
+
+static void mock_init_hdm_type3_cxled(struct cxl_endpoint_decoder *cxled,
+ struct cxl_port *port,
+ struct platform_device *pdev)
+{
+ struct acpi_cedt_cfmws *window = mock_cfmws[0];
+ struct cxl_decoder *cxld = &cxled->cxld;
+ struct cxl_switch_decoder *cxlsd;
+ struct cxl_dport *dport;
+ struct cxl_port *iter;
+ struct device *dev;
+ u64 base;
+ int i;

base = window->base_hpa;
if (extended_linear_cache)
@@ -1208,8 +1189,73 @@ static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
cxld_registry_update(cxld);
put_device(dev);
}
+}

- return false;
+/*
+ * Initialize a decoder during HDM enumeration.
+ *
+ * If a saved registry entry exists:
+ * - enabled decoders are restored from the saved programming
+ * - disabled decoders are initialized in a clean disabled state
+ *
+ * If no registry entry exists the decoder follows the normal mock
+ * initialization path, including the special auto-region setup for
+ * the first endpoints under host-bridge0.
+ *
+ * Returns true if decoder state was restored from the registry. In
+ * that case the saved decode configuration (including target mapping)
+ * has already been applied and the map_targets() is skipped.
+ */
+static bool mock_init_hdm_decoder(struct cxl_decoder *cxld)
+{
+ struct cxl_endpoint_decoder *cxled = NULL;
+ struct platform_device *pdev = NULL;
+ struct cxl_test_decoder *td;
+ struct cxl_memdev *cxlmd;
+ struct cxl_port *port;
+ bool hb0 = false;
+
+ if (is_endpoint_decoder(&cxld->dev)) {
+ cxled = to_cxl_endpoint_decoder(&cxld->dev);
+ cxlmd = cxled_to_memdev(cxled);
+ WARN_ON(!dev_is_platform(cxlmd->dev.parent));
+ pdev = to_platform_device(cxlmd->dev.parent);
+
+ /* check is endpoint is attach to host-bridge0 */
+ port = cxled_to_port(cxled);
+ do {
+ if (port->uport_dev == &cxl_host_bridge[0]->dev) {
+ hb0 = true;
+ break;
+ }
+ if (is_cxl_port(port->dev.parent))
+ port = to_cxl_port(port->dev.parent);
+ else
+ port = NULL;
+ } while (port);
+ port = cxled_to_port(cxled);
+ } else {
+ port = to_cxl_port(cxld->dev.parent);
+ }
+
+ switch (get_decoder_init_type(cxld, pdev, hb0, &td)) {
+ case MOCK_DECODER_INIT_SAVED:
+ if (!td)
+ return false;
+ return mock_decoder_handle_saved(cxld, td);
+ case MOCK_DECODER_INIT_DEFAULT:
+ /*
+ * The default path picks up all the decoders that are not
+ * endpoint.
+ */
+ default_mock_decoder(cxld);
+ return false;
+ case MOCK_DECODER_INIT_TYPE3_AUTO:
+ mock_init_hdm_type3_cxled(cxled, port, pdev);
+ return false;
+ default:
+ return false;
+ }
}

static int mock_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm,
--
2.53.0