cbfs: new API and better program loading

A new CBFS API is introduced to allow making CBFS access
easier for providing multiple CBFS sources. That is achieved
by decoupling the cbfs source from a CBFS file. A CBFS
source is described by a descriptor. It contains the necessary
properties for walking a CBFS to locate a file. The CBFS
file is then decoupled from the CBFS descriptor in that it's
no longer needed to access the contents of the file.

All of this is accomplished using the regions infrastructure
by repsenting CBFS sources and files as region_devices. Because
region_devices can be chained together forming subregions this
allows one to decouple a CBFS source from a file. This also allows
one to provide CBFS files that came from other sources for
payload and/or stage loading.

The program loading takes advantage of those very properties
by allowing multiple sources for locating a program. Because of
this we can reduce the overhead of loading programs because
it's all done in the common code paths. Only locating the
program is per source.

Change-Id: I339b84fce95f03d1dbb63a0f54a26be5eb07f7c8
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9134
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

1 files changed, 15 insertions, 7 deletions

diff --git a/src/include/program_loading.h b/src/include/program_loading.h
index 981bd7b55731..eb9935020a9d 100644
--- a/src/include/program_loading.h
+++ b/src/include/program_loading.h
@@ -22,6 +22,7 @@
 
 #include <stdint.h>
 #include <stddef.h>
+#include <region.h>
 
 enum {
 	/* Last segment of program. Can be used to take different actions for
@@ -42,17 +43,22 @@ enum prog_type {
 	PROG_VERSTAGE,
 	PROG_ROMSTAGE,
 	PROG_RAMSTAGE,
+	PROG_REFCODE,
 	PROG_PAYLOAD,
+	PROG_BL31,
 };
 
 /* Representation of a program. */
 struct prog {
 	enum prog_type type;
 	const char *name;
+	/* Source of program content to load. */
+	struct region_device rdev;
 	/* The area can mean different things depending on what type the
-	 * program is. e.g. a payload prog uses this field for the backing
-	 * store of the payload_segments and data. After loading the segments
-	 * area is updated to reflect the bounce buffer used. */
+	 * program is. A stage after being loaded reflects the memory occupied
+	 * by the program, Since payloads are multi-segment one can't express
+	 * the memory layout with one range. Instead this field is updated
+	 * to reflect the bounce buffer used. */
 	struct buffer_area area;
 	/* Entry to program with optional argument. It's up to the architecture
 	 * to decide if argument is passed. */
@@ -92,6 +98,8 @@ static inline void prog_set_entry(struct prog *prog, void *e, void *arg)
 	prog->arg = arg;
 }
 
+/* Locate the identified program to run. Return 0 on success. < 0 on error. */
+int prog_locate(struct prog *prog);
 /* Run the program described by prog. */
 void prog_run(struct prog *prog);
 /* Per architecture implementation running a program. */
@@ -107,10 +115,10 @@ struct prog_loader_ops {
 	/* Determine if the loader is the active one. If so returns 1 else 0
 	 * or < 0 on error. */
 	int (*is_loader_active)(struct prog *prog);
-	/* Returns < 0 on error or 0 on success. This function needs to do
-	 * different things depending on the prog type. See definition
-	 * of struct prog above. */
-	int (*prepare)(struct prog *prog);
+	/* Returns < 0 on error or 0 on success. This function locates
+	 * the rdev representing the file data associated with the passed in
+	 * prog. */
+	int (*locate)(struct prog *prog);
 };
 
 /************************