[PATCH 2/4] cxl/pci: Use CXL_MBOX_SUCCESS to check against mbox_cmd return code

[Davidlohr Bueso <dave@stgolabs.net>]

Also mention the need for the caller to check against any
errors from the hardware in return_code.

Reviewed by: Adam Manzanares <a.manzanares@samsung.com>
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
---
 drivers/cxl/pci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 8a7267d116b7..8b131692ed61 100644
--- a/drivers/cxl/pci.c
+++ b/drivers/cxl/pci.c
@@ -177,9 +177,9 @@ static int __cxl_pci_mbox_send_cmd(struct cxl_dev_state *cxlds,
 	mbox_cmd->return_code =
 		FIELD_GET(CXLDEV_MBOX_STATUS_RET_CODE_MASK, status_reg);
 
-	if (mbox_cmd->return_code != 0) {
+	if (mbox_cmd->return_code != CXL_MBOX_SUCCESS) {
 		dev_dbg(dev, "Mailbox operation had an error\n");
-		return 0;
+		return 0; /* completed but caller must check return_code */
 	}
 
 	/* #7 */
-- 
2.26.2