GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/trusted-firmware/trusted-firmware-a-2.8/lib/extensions/brbe/brbe.c

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <arch_features.h>
+#include <arch_helpers.h>
+
+void brbe_enable(void)
+{
+	uint64_t val;
+
+	if (is_feat_brbe_present()) {
+		/*
+		 * MDCR_EL3.SBRBE = 0b01
+		 *
+		 * Allows BRBE usage in non-secure world and prohibited in
+		 * secure world.
+		 */
+		val = read_mdcr_el3();
+		val &= ~(MDCR_SBRBE_MASK << MDCR_SBRBE_SHIFT);
+		val |= (0x1UL << MDCR_SBRBE_SHIFT);
+		write_mdcr_el3(val);
+	}
+}