cxl/pci: Use CXL_MBOX_SUCCESS to check against mbox_cmd return code

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

Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Reviewed by: Adam Manzanares <a.manzanares@samsung.com>
Link: https://lore.kernel.org/r/20220404021216.66841-3-dave@stgolabs.net
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
index 3f2182d6682929681b27adb2cbbcec313d7e6f21..94a91048e2f68222dbbf2661f66480bb1fad1434 100644 (file)
--- 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 */