coreboot: tiered imd

A tiered imd allows for both small and large allocations. The
small allocations are packed into a large region. Utilizing a
tiered imd reduces internal fragmentation within the imd.

Change-Id: I0bcd6473aacbc714844815b24d77cb5c542abdd0
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/8623
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/src/include/imd.h b/src/include/imd.h
index 8d5c4522b7..a444b4fbb1 100644
--- a/src/include/imd.h
+++ b/src/include/imd.h
@@ -82,6 +82,18 @@ void imd_handle_init_partial_recovery(struct imd *imd);
 int imd_create_empty(struct imd *imd, size_t root_size, size_t entry_align);
 
 /*
+ * Create an empty imd with both large and small allocations. The small
+ * allocations come from a fixed imd stored internally within the large
+ * imd. The region allocated for tracking the smaller allocations is dependent
+ * on the small root_size and the large entry alignment by calculating the
+ * number of entries within the small imd and multiplying that by the small
+ * entry alignment.
+ */
+int imd_create_tiered_empty(struct imd *imd,
+				size_t lg_root_size, size_t lg_entry_align,
+				size_t sm_root_size, size_t sm_entry_align);
+
+/*
  * Recover a previously created imd.
  */
 int imd_recover(struct imd *imd);
@@ -131,9 +143,13 @@ int imd_print_entries(const struct imd *imd, const struct imd_lookup *lookup,
  * NOTE: Do not directly touch any fields within this structure. An imd pointer
  * is meant to be opaque, but the fields are exposed for stack allocation.
  */
-struct imd {
+struct imdr {
 	uintptr_t limit;
 	void *r;
 };
+struct imd {
+	struct imdr lg;
+	struct imdr sm;
+};
 
 #endif /* _IMD_H_ */