diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index c222e98ae736..3930e130d6b6 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -177,7 +177,7 @@ static struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port,
 	}
 
 	parse_hdm_decoder_caps(cxlhdm);
-	if (cxlhdm->decoder_count == 0) {
+	if (cxlhdm->decoder_count < 0) {
 		dev_err(dev, "Spec violation. Caps invalid\n");
 		return ERR_PTR(-ENXIO);
 	}
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 28a49c20df58..1297594beaec 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -78,7 +78,16 @@ static inline int cxl_hdm_decoder_count(u32 cap_hdr)
 {
 	int val = FIELD_GET(CXL_HDM_DECODER_COUNT_MASK, cap_hdr);
 
-	return val ? val * 2 : 1;
+	switch (val) {
+	case 0:
+		return 1;
+	case 1 ... 8:
+		return val * 2;
+	case 9 ... 12:
+		return (val - 4) * 4;
+	default:
+		return -ENXIO;
+	}
 }
 
 /* Encode defined in CXL 2.0 8.2.5.12.7 HDM Decoder Control Register */
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 02054f233fc5..776c50d1db51 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -841,7 +841,7 @@ int cxl_mem_sanitize(struct cxl_memdev *cxlmd, u16 cmd);
  */
 struct cxl_hdm {
 	struct cxl_component_regs regs;
-	unsigned int decoder_count;
+	int decoder_count;
 	unsigned int target_count;
 	unsigned int interleave_mask;
 	unsigned long iw_cap_mask;