fconf: initial commit

Introduce the Firmware CONfiguration Framework (fconf).

The fconf is an abstraction layer for platform specific data, allowing
a "property" to be queried and a value retrieved without the requesting
entity knowing what backing store is being used to hold the data.

The default backing store used is C structure. If another backing store
has to be used, the platform integrator needs to provide a "populate()"
function to fill the corresponding C structure.
The "populate()" function must be registered to the fconf framework with
the "FCONF_REGISTER_POPULATOR()". This ensures that the function would
be called inside the "fconf_populate()" function.

A two level macro is used as getter:
- the first macro takes 3 parameters and converts it to a function
  call: FCONF_GET_PROPERTY(a,b,c) -> a__b_getter(c).
- the second level defines a__b_getter(c) to the matching C structure,
  variable, array, function, etc..

Ex: Get a Chain of trust property:
    1) FCONF_GET_PROPERY(tbbr, cot, BL2_id) -> tbbr__cot_getter(BL2_id)
    2) tbbr__cot_getter(BL2_id) -> cot_desc_ptr[BL2_id]

Change-Id: Id394001353ed295bc680c3f543af0cf8da549469
Signed-off-by: Louis Mayencourt <louis.mayencourt@arm.com>

2 files changed, 51 insertions, 0 deletions

diff --git a/lib/fconf/fconf.c b/lib/fconf/fconf.c
new file mode 100644
index 000000000..387e758d2
--- /dev/null
+++ b/lib/fconf/fconf.c
@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2019-2020, ARM Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <common/debug.h>
+#include <lib/fconf/fconf.h>
+#include <libfdt.h>
+#include <platform_def.h>
+
+void fconf_populate(uintptr_t config)
+{
+	assert(config != 0UL);
+
+	/* Check if the pointer to DTB is correct */
+	if (fdt_check_header((void *)config) != 0) {
+		ERROR("FCONF: Invalid DTB file passed for FW_CONFIG\n");
+		panic();
+	}
+
+	INFO("FCONF: Reading firmware configuration file from: 0x%lx\n", config);
+
+	/* Go through all registered populate functions */
+	IMPORT_SYM(struct fconf_populator *, __FCONF_POPULATOR_START__, start);
+	IMPORT_SYM(struct fconf_populator *, __FCONF_POPULATOR_END__, end);
+	const struct fconf_populator *populator;
+
+	for (populator = start; populator != end; populator++) {
+		assert((populator->info != NULL) && (populator->populate != NULL));
+
+		INFO("FCONF: Reading firmware configuration information for: %s\n", populator->info);
+		if (populator->populate(config) != 0) {
+			/* TODO: handle property miss */
+			panic();
+		}
+	}
+}
diff --git a/lib/fconf/fconf.mk b/lib/fconf/fconf.mk
new file mode 100644
index 000000000..0813c73cc
--- /dev/null
+++ b/lib/fconf/fconf.mk
@@ -0,0 +1,11 @@
+#
+# Copyright (c) 2019-2020, ARM Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+# Add Firmware Configuration files
+FCONF_SOURCES		:=	lib/fconf/fconf.c
+
+BL1_SOURCES		+=	${FCONF_SOURCES}
+BL2_SOURCES		+=	${FCONF_SOURCES}