cbfs: Add metadata cache

This patch adds a new CBFS "mcache" (metadata cache) -- a memory buffer
that stores the headers of all CBFS files. Similar to the existing FMAP
cache, this cache should reduce the amount of SPI accesses we need to do
every boot: rather than having to re-read all CBFS headers from SPI
flash every time we're looking for a file, we can just walk the same
list in this in-memory copy and finally use it to directly access the
flash at the right position for the file data.

This patch adds the code to support the cache but doesn't enable it on
any platform. The next one will turn it on by default.

Change-Id: I5b1084bfdad1c6ab0ee1b143ed8dd796827f4c65
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38423
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 18 insertions, 5 deletions

diff --git a/src/include/cbfs.h b/src/include/cbfs.h
index a35597d5b1..32ed7f899e 100644
--- a/src/include/cbfs.h
+++ b/src/include/cbfs.h
@@ -3,10 +3,10 @@
 #ifndef _CBFS_H_
 #define _CBFS_H_
 
+#include <cbmem.h>
 #include <commonlib/cbfs.h>
 #include <program_loading.h>
-#include <stddef.h>
-#include <stdint.h>
+#include <types.h>
 
 /***********************************************
  * Perform CBFS operations on the boot device. *
@@ -42,8 +42,21 @@ size_t cbfs_load_and_decompress(const struct region_device *rdev, size_t offset,
 /* Load stage into memory filling in prog. Return 0 on success. < 0 on error. */
 int cbfs_prog_stage_load(struct prog *prog);
 
-/* Returns the region device of the currently active CBFS.
-   Return < 0 on error, 0 on success. */
-int cbfs_boot_region_device(struct region_device *rdev);
+struct cbfs_boot_device {
+	struct region_device rdev;
+	void *mcache;
+	size_t mcache_size;
+};
+
+/* Helper to fill out |mcache| and |mcache_size| in a cbfs_boot_device. */
+void cbfs_boot_device_find_mcache(struct cbfs_boot_device *cbd, uint32_t id);
+
+/*
+ * Retrieves the currently active CBFS boot device. If |force_ro| is set, will
+ * always return the read-only CBFS instead (this only makes a difference when
+ * CONFIG(VBOOT) is enabled). May perform certain CBFS initialization tasks.
+ * Returns NULL on error (e.g. boot device IO error).
+ */
+const struct cbfs_boot_device *cbfs_get_boot_device(bool force_ro);
 
 #endif