}
break;
+ case 52:
+ case 53:
+ /* CMD52, CMD53: reserved for SDIO cards
+ * (see the SDIO Simplified Specification V2.0)
+ * Handle as illegal command but do not complain
+ * on stderr, as some OSes may use these in their
+ * probing for presence of an SDIO card.
+ */
+ sd->card_status |= ILLEGAL_COMMAND;
+ return sd_r0;
+
/* Application specific commands (Class 8) */
case 55: /* CMD55: APP_CMD */
if (sd->rca != rca)