ufshci: fail attribute reads on a non-zero config result code

ufshci_uic_send_cmd() only logged the error code and returned success,
so a failed DME_GET gave its caller a stale value as if it were valid.
The gear and lane settings could then be programmed from that garbage.

Return ENXIO for reads instead. Writes keep logging and continuing,
because a device may reject an optional attribute and that must not
fail bring-up.

Sponsored by:           Samsung Electronics
Reviewed by		imp (mentor)
Differential Revision:	https://reviews.freebsd.org/D58654

1 files changed, 8 insertions, 0 deletions

diff --git a/sys/dev/ufshci/ufshci_uic_cmd.c b/sys/dev/ufshci/ufshci_uic_cmd.c
index c6e6afe3f688..03ea8b2ba9f1 100644
--- a/sys/dev/ufshci/ufshci_uic_cmd.c
+++ b/sys/dev/ufshci/ufshci_uic_cmd.c
@@ -199,6 +199,14 @@ ufshci_uic_send_cmd(struct ufshci_controller *ctrlr,
 		    "Failed to send UIC command (Opcode: 0x%x"
 		    ", config result code = 0x%x)\n",
 		    uic_cmd->opcode, config_result_code);
+		/*
+		 * Reads fail here: there is no valid result to return.
+		 * Writes only log the error, so that a rejected optional
+		 * attribute does not fail bring-up.
+		 */
+		if (return_value != NULL)
+			return (ENXIO);
+		return (0);
 	}
 
 	if (return_value != NULL)