diff --git a/plat/nvidia/tegra/soc/t186/drivers/include/mce_private.h b/plat/nvidia/tegra/soc/t186/drivers/include/mce_private.h
index 96a5525a6..203f61a5d 100644
--- a/plat/nvidia/tegra/soc/t186/drivers/include/mce_private.h
+++ b/plat/nvidia/tegra/soc/t186/drivers/include/mce_private.h
@@ -64,19 +64,17 @@
 #define MCA_ARG_FINISH_MASK			U(0xFF)
 
 /*******************************************************************************
- * Uncore PERFMON ARI struct
+ * Uncore PERFMON ARI macros
  ******************************************************************************/
 #define UNCORE_PERFMON_CMD_READ			U(0)
 #define UNCORE_PERFMON_CMD_WRITE		U(1)
 
 #define UNCORE_PERFMON_CMD_MASK			U(0xFF)
-#define UNCORE_PERFMON_CMD_SHIFT		U(24)
 #define UNCORE_PERFMON_UNIT_GRP_MASK		U(0xF)
 #define UNCORE_PERFMON_SELECTOR_MASK		U(0xF)
 #define UNCORE_PERFMON_REG_MASK			U(0xFF)
 #define UNCORE_PERFMON_CTR_MASK			U(0xFF)
 #define UNCORE_PERFMON_RESP_STATUS_MASK		U(0xFF)
-#define UNCORE_PERFMON_RESP_STATUS_SHIFT	U(24)
 
 /*******************************************************************************
  * Structure populated by arch specific code to export routines which perform
diff --git a/plat/nvidia/tegra/soc/t186/drivers/mce/ari.c b/plat/nvidia/tegra/soc/t186/drivers/mce/ari.c
index 602a0562d..a57bc11b9 100644
--- a/plat/nvidia/tegra/soc/t186/drivers/mce/ari.c
+++ b/plat/nvidia/tegra/soc/t186/drivers/mce/ari.c
@@ -503,7 +503,7 @@ int32_t ari_read_write_uncore_perfmon(uint32_t ari_base, uint64_t req,
 	uint32_t val, req_status;
 	uint8_t req_cmd;
 
-	req_cmd = (uint8_t)(req >> UNCORE_PERFMON_CMD_SHIFT);
+	req_cmd = (uint8_t)(req & UNCORE_PERFMON_CMD_MASK);
 
 	/* clean the previous response state */
 	ari_clobber_response(ari_base);
@@ -533,7 +533,7 @@ int32_t ari_read_write_uncore_perfmon(uint32_t ari_base, uint64_t req,
 			 * For "read" commands get the data from the uncore
 			 * perfmon registers
 			 */
-			req_status >>= UNCORE_PERFMON_RESP_STATUS_SHIFT;
+			req_status &= UNCORE_PERFMON_RESP_STATUS_MASK;
 			if ((req_status == 0U) && (req_cmd == UNCORE_PERFMON_CMD_READ)) {
 				*data = ari_get_response_low(ari_base);
 			}