stage_cache: make prog const in stage_cache_add()

The stage_cache_add() function should not be manipulating
the struct prog argument in anyway. Therefore, mark it as
const.

BUG=chrome-os-partner:43636
BRANCH=None
TEST=Built, booted, suspended, and resumed on glados.

Original-Change-Id: I4509e478d3c98247b9d776f6534b949d9ba6282c
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/290721
Original-Reviewed-by: Leroy P Leahy <leroy.p.leahy@intel.com>
Original-Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

Change-Id: Ibadc00a9e1cbbf12119def92d77a79077625fb85
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/11192
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/include/stage_cache.h

@@ -30,7 +30,7 @@ enum {
 };
 
 /* Cache the loaded stage provided according to the parameters. */
-void stage_cache_add(int stage_id, struct prog *stage);
+void stage_cache_add(int stage_id, const struct prog *stage);
 /* Load the cached stage at given location returning the stage entry point. */
 void stage_cache_load_stage(int stage_id, struct prog *stage);
 /* Fill in parameters for the external stage cache, if utilized. */

src/lib/cbmem_stage_cache.c

@@ -23,7 +23,7 @@
 #include <string.h>
 
 /* Stage cache uses cbmem. */
-void stage_cache_add(int stage_id, struct prog *stage)
+void stage_cache_add(int stage_id, const struct prog *stage)
 {
 	struct stage_cache *meta;
 	void *c;

src/lib/ext_stage_cache.c

@@ -62,7 +62,7 @@ static void stage_cache_recover(void)
 		printk(BIOS_DEBUG, "Unable to recover external stage cache.\n");
 }
 
-void stage_cache_add(int stage_id, struct prog *stage)
+void stage_cache_add(int stage_id, const struct prog *stage)
 {
 	struct imd *imd;
 	const struct imd_entry *e;

src/lib/prog_loaders.c

@@ -60,7 +60,8 @@ fail:
 	halt();
 }
 
-void __attribute__((weak)) stage_cache_add(int stage_id, struct prog *stage) {}
+void __attribute__((weak)) stage_cache_add(int stage_id,
+						const struct prog *stage) {}
 void __attribute__((weak)) stage_cache_load_stage(int stage_id,
 							struct prog *stage) {}
 void __attribute__((weak)) ramstage_cache_invalid(void) {}