2 files changed, 109 insertions, 0 deletions
diff --git a/lib/coreboot/coreboot.mk b/lib/coreboot/coreboot.mk
new file mode 100644
index 00000000..0cd103f2
--- /dev/null
+++ b/lib/coreboot/coreboot.mk
@@ -0,0 +1,20 @@
+#
+# Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+COREBOOT := 0
+$(eval $(call assert_boolean,COREBOOT))
+$(eval $(call add_define,COREBOOT))
+
+ifeq (${COREBOOT},1)
+
+ifneq (${ARCH},aarch64)
+$(error "coreboot only supports Trusted Firmware on AArch64.")
+endif
+
+BL31_SOURCES	+=	$(addprefix lib/coreboot/,	\
+			coreboot_table.c)
+
+endif	# COREBOOT
diff --git a/lib/coreboot/coreboot_table.c b/lib/coreboot/coreboot_table.c
new file mode 100644
index 00000000..76e5d3b7
--- /dev/null
+++ b/lib/coreboot/coreboot_table.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <coreboot.h>
+#include <debug.h>
+#include <mmio.h>
+#include <string.h>
+
+/*
+ * Structures describing coreboot's in-memory descriptor tables. See
+ * <coreboot>/src/commonlib/include/commonlib/coreboot_tables.h for
+ * canonical implementation.
+ */
+
+typedef struct {
+	char signature[4];
+	uint32_t header_bytes;
+	uint32_t header_checksum;
+	uint32_t table_bytes;
+	uint32_t table_checksum;
+	uint32_t table_entries;
+} cb_header_t;
+
+typedef enum {
+	CB_TAG_SERIAL = 0xf,
+} cb_tag_t;
+
+typedef struct {
+	uint32_t tag;
+	uint32_t size;
+	union {
+		coreboot_serial_t serial;
+	};
+} cb_entry_t;
+
+coreboot_serial_t coreboot_serial;
+
+/*
+ * The coreboot table is parsed before the MMU is enabled (i.e. with strongly
+ * ordered memory), so we cannot make unaligned accesses. The table entries
+ * immediately follow one another without padding, so nothing after the header
+ * is guaranteed to be naturally aligned. Therefore, we need to define safety
+ * functions that can read unaligned integers.
+ */
+static uint32_t read_le32(uint32_t *p)
+{
+	uintptr_t addr = (uintptr_t)p;
+	return mmio_read_8(addr)		|
+	       mmio_read_8(addr + 1) << 8	|
+	       mmio_read_8(addr + 2) << 16	|
+	       mmio_read_8(addr + 3) << 24;
+}
+
+void coreboot_table_setup(void *base)
+{
+	cb_header_t *header = base;
+	void *ptr;
+	int i;
+
+	if (strncmp(header->signature, "LBIO", 4)) {
+		ERROR("coreboot table signature corrupt!\n");
+		return;
+	}
+
+	ptr = base + header->header_bytes;
+	for (i = 0; i < header->table_entries; i++) {
+		cb_entry_t *entry = ptr;
+
+		if (ptr - base >= header->header_bytes + header->table_bytes) {
+			ERROR("coreboot table exceeds its bounds!\n");
+			break;
+		}
+
+		switch (read_le32(&entry->tag)) {
+		case CB_TAG_SERIAL:
+			memcpy(&coreboot_serial, &entry->serial,
+			       sizeof(coreboot_serial));
+			break;
+		default:
+			/* There are many tags TF doesn't need to care about. */
+			break;
+		}
+
+		ptr += read_le32(&entry->size);
+	}
+}