[PATCH] nvme-pci: ignore bogus CRTO according to NVME 2.0 spec

[Felix Yan]

NVME 2.0 spec section 3.1.3 suggests that "Software should not rely on
0h being returned". Here we should safeguard timeout reads when CRTO is 0 and
fallback to the old NVME 1.4 compatible field.

Fixes 4TB SSD initialization issues with MAXIO MAP1602 controller, including
Lexar NM790, AIGO P7000Z, Fanxiang S790, Acer Predator GM7, etc.

----------
nvme nvme1: Device not ready; aborting initialisation, CSTS=0x0
----------

Signed-off-by: Felix Yan <felixonmars@xxxxxxxxxxxxx>
---
 drivers/nvme/host/core.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index f3a01b79148c..8ec28b1016ca 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2255,11 +2255,17 @@ int nvme_enable_ctrl(struct nvme_ctrl *ctrl)
 			return ret;
 		}
 
-		if (ctrl->cap & NVME_CAP_CRMS_CRIMS) {
-			ctrl->ctrl_config |= NVME_CC_CRIME;
-			timeout = NVME_CRTO_CRIMT(crto);
+		if (crto == 0) {
+			timeout = NVME_CAP_TIMEOUT(ctrl->cap);
+			dev_warn(ctrl->device, "Ignoring bogus CRTO (0), falling back to NVME_CAP_TIMEOUT (%u)\n",
+				timeout);
 		} else {
-			timeout = NVME_CRTO_CRWMT(crto);
+			if (ctrl->cap & NVME_CAP_CRMS_CRIMS) {
+				ctrl->ctrl_config |= NVME_CC_CRIME;
+				timeout = NVME_CRTO_CRIMT(crto);
+			} else {
+				timeout = NVME_CRTO_CRWMT(crto);
+			}
 		}
 	} else {
 		timeout = NVME_CAP_TIMEOUT(ctrl->cap);
-- 
2.42.0