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>
diff --git a/include/lib/fconf/fconf.h b/include/lib/fconf/fconf.h
new file mode 100644
index 0000000..c5f10d2
--- /dev/null
+++ b/include/lib/fconf/fconf.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2019-2020, ARM Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef FCONF_H
+#define FCONF_H
+
+#include <stdint.h>
+
+/* Public API */
+#define FCONF_GET_PROPERTY(a, b, c) a##__##b##_getter(c)
+
+#define FCONF_REGISTER_POPULATOR(name, callback) \
+ __attribute__((used, section(".fconf_populator"))) \
+ const struct fconf_populator name##__populator = { \
+ .info = #name, \
+ .populate = callback \
+ };
+
+/*
+ * Populator callback
+ *
+ * This structure are used by the fconf_populate function and should only be
+ * defined by the FCONF_REGISTER_POPULATOR macro.
+ */
+struct fconf_populator {
+ /* Description of the data loaded by the callback */
+ const char *info;
+
+ /* Callback used by fconf_populate function with a provided config dtb.
+ * Return 0 on success, err_code < 0 otherwise.
+ */
+ int (*populate)(uintptr_t config);
+};
+
+/* Top level populate function
+ *
+ * This function takes a configuration dtb and calls all the registered
+ * populator callback with it.
+ *
+ * Panic on error.
+ */
+void fconf_populate(uintptr_t config);
+
+#endif /* FCONF_H */