cleanup: add some easier-to-use FMAP parsing functions.

The functions that look for the FMAP and its entries should return more
useful values.

BUG=none
BRANCH=ToT
TEST=make runtests

No functional changes.

Change-Id: I4b62ea0de972bceb3d58f4ee8eb82ad065ddcbae
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/214630
Reviewed-by: Randall Spangler <rspangler@chromium.org>

3 files changed, 53 insertions, 41 deletions

diff --git a/futility/cmd_dump_fmap.c b/futility/cmd_dump_fmap.c
index 14bedac6..d1c962cc 100644
--- a/futility/cmd_dump_fmap.c
+++ b/futility/cmd_dump_fmap.c
@@ -30,13 +30,12 @@ static size_t size_of_rom;
 static int opt_gaps = 0;
 
 /* Return 0 if successful */
-static int dump_fmap(const void *ptr, int argc, char *argv[])
+static int dump_fmap(const FmapHeader *fmh, int argc, char *argv[])
 {
 	int i, retval = 0;
 	char buf[80];		/* DWR: magic number */
-	const FmapHeader *fmh = (const FmapHeader *)ptr;
-	const FmapAreaHeader *ah =
-	    (const FmapAreaHeader *)(ptr + sizeof(FmapHeader));
+	const FmapAreaHeader *ah;
+	ah = (const FmapAreaHeader *) (fmh + 1);
 
 	if (FMT_NORMAL == opt_format) {
 		snprintf(buf, FMAP_SIGNATURE_SIZE + 1, "%s",
@@ -260,14 +259,12 @@ static void add_child(node_t * p, int n)
 		}
 }
 
-static int human_fmap(void *p)
+static int human_fmap(const FmapHeader *fmh)
 {
-	FmapHeader *fmh;
 	FmapAreaHeader *ah;
 	int i, j, errorcnt = 0;
 	int numnodes;
 
-	fmh = (FmapHeader *) p;
 	ah = (FmapAreaHeader *) (fmh + 1);
 
 	/* The challenge here is to generate a directed graph from the
@@ -384,7 +381,7 @@ static int do_dump_fmap(int argc, char *argv[])
 	int errorcnt = 0;
 	struct stat sb;
 	int fd;
-	const char *fmap;
+	const FmapHeader *fmap;
 	int retval = 1;
 
 	progname = strrchr(argv[0], '/');
@@ -457,15 +454,15 @@ static int do_dump_fmap(int argc, char *argv[])
 	close(fd);		/* done with this now */
 	size_of_rom = sb.st_size;
 
-	fmap = FmapFind((char *)base_of_rom, size_of_rom);
+	fmap = fmap_find(base_of_rom, size_of_rom);
 	if (fmap) {
 		switch (opt_format) {
 		case FMT_HUMAN:
-			retval = human_fmap((void *)fmap);
+			retval = human_fmap(fmap);
 			break;
 		case FMT_NORMAL:
 			printf("hit at 0x%08x\n",
-			       (uint32_t) (fmap - (char *)base_of_rom));
+			       (uint32_t) ((char *)fmap - (char *)base_of_rom));
 			/* fallthrough */
 		default:
 			retval =
diff --git a/host/lib/fmap.c b/host/lib/fmap.c
index 014c97b2..f9b0e5ed 100644
--- a/host/lib/fmap.c
+++ b/host/lib/fmap.c
@@ -9,27 +9,41 @@
 
 #include "fmap.h"
 
-const char* FmapFind(const char* ptr, size_t size)
+/* Find and point to the FMAP header within the buffer */
+FmapHeader *fmap_find(uint8_t *ptr, size_t size)
 {
-  size_t i;
-  FmapHeader *fmap_header;
-  for (i=0; i<size; i += FMAP_SEARCH_STRIDE, ptr += FMAP_SEARCH_STRIDE) {
-    if (0 != strncmp(ptr, FMAP_SIGNATURE, FMAP_SIGNATURE_SIZE))
-      continue;
-    // Image may have multiple signatures (ex, in code that handles FMAP itself)
-    // so we do want to check at least major version.
-    fmap_header = (FmapHeader *)ptr;
-    if (fmap_header->fmap_ver_major == FMAP_VER_MAJOR)
-      return ptr;
-  }
-  return NULL;
+	size_t i;
+	FmapHeader *fmap_header;
+	for (i=0; i<size; i += FMAP_SEARCH_STRIDE, ptr += FMAP_SEARCH_STRIDE) {
+		if (0 != memcmp(ptr, FMAP_SIGNATURE, FMAP_SIGNATURE_SIZE))
+			continue;
+		fmap_header = (FmapHeader *)ptr;
+		if (fmap_header->fmap_ver_major == FMAP_VER_MAJOR)
+			return fmap_header;
+	}
+	return NULL;
 }
 
-int FmapAreaIndex(const FmapHeader* fh, const FmapAreaHeader* ah,
-		const char* name) {
-  int i;
-  for (i = 0; i < fh->fmap_nareas; i++)
-    if (!strcmp((const char*) ah[i].area_name, name))
-      return i;
-  return -1;
+/* Search for an area by name, return pointer to its beginning */
+uint8_t *fmap_find_by_name(uint8_t *ptr, size_t size, FmapHeader *fmap,
+			   const char *name, FmapAreaHeader **ah_ptr)
+{
+	int i;
+	FmapAreaHeader *ah;
+
+	if (!fmap)
+		fmap = fmap_find(ptr, size);
+	if (!fmap)
+		return NULL;
+
+	ah = (FmapAreaHeader*)((void *)fmap + sizeof(FmapHeader));
+	for (i = 0; i < fmap->fmap_nareas; i++)
+		if (!strncmp(ah[i].area_name, name, FMAP_NAMELEN)) {
+			if (ah_ptr)
+				*ah_ptr = ah + i;
+			return ptr + ah[i].area_offset;
+		}
+
+	return NULL;
 }
+
diff --git a/host/lib/include/fmap.h b/host/lib/include/fmap.h
index 92d74fd3..7e627050 100644
--- a/host/lib/include/fmap.h
+++ b/host/lib/include/fmap.h
@@ -34,15 +34,16 @@ typedef struct _FmapAreaHeader {
 } __attribute__((packed)) FmapAreaHeader;
 
 
-/* Scan firmware image, pointed by [ptr] with length [size], for fmap header.
- * Return pointer to fmap header, or NULL if not found.
- */
-const char* FmapFind(const char *ptr, size_t size);
-
-/* Look up fmap area by name, that is, strcmp(fh->fmap_name, name) == 0.
- * Return index of fmap area, that is, ah[returned_index],
- * or -1 if not found. */
-int FmapAreaIndex(const FmapHeader* fh, const FmapAreaHeader* ah,
-		const char* name);
+/* Find and point to the FMAP header within the buffer */
+FmapHeader *fmap_find(uint8_t *ptr, size_t size);
+
+/* Search for an area by name, return pointer to its beginning */
+uint8_t *fmap_find_by_name(uint8_t *ptr, size_t size,
+			   /* optional, will call fmap_find() if NULL */
+			   FmapHeader *fmap,
+			   /* The area name to search for */
+			   const char *name,
+			   /* optional, return pointer to entry if not NULL */
+			   FmapAreaHeader **ah);
 
 #endif  /* __FMAP_H__ */