4 files changed, 37 insertions, 6 deletions

diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index dcc16d7cb8f3..c0f224454447 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -679,9 +679,34 @@ static int cxl_decoder_reset(struct cxl_decoder *cxld)
 	return 0;
 }
 
+static int cxl_setup_hdm_decoder_from_dvsec(struct cxl_port *port,
+					    struct cxl_decoder *cxld, int which,
+					    struct cxl_endpoint_dvsec_info *info)
+{
+	if (!is_cxl_endpoint(port))
+		return -EOPNOTSUPP;
+
+	if (!range_len(&info->dvsec_range[which]))
+		return -ENOENT;
+
+	cxld->target_type = CXL_DECODER_EXPANDER;
+	cxld->commit = NULL;
+	cxld->reset = NULL;
+	cxld->hpa_range = info->dvsec_range[which];
+
+	/*
+	 * Set the emulated decoder as locked pending additional support to
+	 * change the range registers at run time.
+	 */
+	cxld->flags |= CXL_DECODER_F_ENABLE | CXL_DECODER_F_LOCK;
+	port->commit_end = cxld->id;
+
+	return 0;
+}
+
 static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
 			    int *target_map, void __iomem *hdm, int which,
-			    u64 *dpa_base)
+			    u64 *dpa_base, struct cxl_endpoint_dvsec_info *info)
 {
 	struct cxl_endpoint_decoder *cxled = NULL;
 	u64 size, base, skip, dpa_size;
@@ -717,6 +742,9 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
 		.end = base + size - 1,
 	};
 
+	if (cxled && !committed && range_len(&info->dvsec_range[which]))
+		return cxl_setup_hdm_decoder_from_dvsec(port, cxld, which, info);
+
 	/* decoders are enabled if committed */
 	if (committed) {
 		cxld->flags |= CXL_DECODER_F_ENABLE;
@@ -790,7 +818,8 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
  * devm_cxl_enumerate_decoders - add decoder objects per HDM register set
  * @cxlhdm: Structure to populate with HDM capabilities
  */
-int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm)
+int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm,
+				struct cxl_endpoint_dvsec_info *info)
 {
 	void __iomem *hdm = cxlhdm->regs.hdm_decoder;
 	struct cxl_port *port = cxlhdm->port;
@@ -842,7 +871,8 @@ int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm)
 			cxld = &cxlsd->cxld;
 		}
 
-		rc = init_hdm_decoder(port, cxld, target_map, hdm, i, &dpa_base);
+		rc = init_hdm_decoder(port, cxld, target_map, hdm, i,
+				      &dpa_base, info);
 		if (rc) {
 			put_device(&cxld->dev);
 			return rc;
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index d0b25481bdce..4df0b35c9b1a 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -426,7 +426,7 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm,
 	 * Decoder Capability Enable.
 	 */
 	if (info->mem_enabled)
-		return -EBUSY;
+		return 0;
 
 	rc = devm_cxl_enable_hdm(&port->dev, cxlhdm);
 	if (rc)
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index fc01ce96d326..fe9d75989c8a 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -644,7 +644,8 @@ struct cxl_endpoint_dvsec_info {
 
 struct cxl_hdm;
 struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port);
-int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm);
+int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm,
+				struct cxl_endpoint_dvsec_info *info);
 int devm_cxl_add_passthrough_decoder(struct cxl_port *port);
 int cxl_dvsec_rr_decode(struct device *dev, int dvsec,
 			struct cxl_endpoint_dvsec_info *info);
diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
index 9e09728b20d9..d3a708e32565 100644
--- a/drivers/cxl/port.c
+++ b/drivers/cxl/port.c
@@ -78,7 +78,7 @@ static int cxl_port_probe(struct device *dev)
 		}
 	}
 
-	rc = devm_cxl_enumerate_decoders(cxlhdm);
+	rc = devm_cxl_enumerate_decoders(cxlhdm, &info);
 	if (rc) {
 		dev_err(dev, "Couldn't enumerate decoders (%d)\n", rc);
 		return rc;