[PATCH] RFC: spl: fit: Use libfdt functions to read stringlist

[Simon Glass]

At present the code here reimplements a few libfdt functions and does not
always respect the property length. The !str check is unlikely to fire
since 1 is added to the string address. If strchr() returns NULL then the
code produces (void*)1 instead. Also it might extend beyond the property
value since strchr() does not have a maximum length.

In any case it does not seem worthwhile to implement the libfdt functions
again, despite small code-size advantages. There is no function to return
the count after a failed get, but we can call two functions. We could add
one if code size is considered critical here.

Update the code to use libfdt directly.

For lion-rk3368 (aarch64) this adds 68 bytes of code.
For am57xx_hs_evm (arm) it adds 134 bytes.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 common/spl/spl_fit.c | 31 +++++++++++--------------------
 1 file changed, 11 insertions(+), 20 deletions(-)

diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
index 75c8ff065bb..3b5307e4b2d 100644
--- a/common/spl/spl_fit.c
+++ b/common/spl/spl_fit.c
@@ -83,33 +83,24 @@ static int spl_fit_get_image_name(const struct spl_fit_info *ctx,
 				  const char **outname)
 {
 	struct udevice *sysinfo;
-	const char *name, *str;
-	__maybe_unused int node;
-	int len, i;
-	bool found = true;
-
-	name = fdt_getprop(ctx->fit, ctx->conf_node, type, &len);
-	if (!name) {
-		debug("cannot find property '%s': %d\n", type, len);
-		return -EINVAL;
-	}
+	const char *str;
+	int count;
+	bool found;
 
-	str = name;
-	for (i = 0; i < index; i++) {
-		str = strchr(str, '\0') + 1;
-		if (!str || (str - name >= len)) {
-			found = false;
-			break;
-		}
-	}
+	count = fdt_stringlist_count(ctx->fit, ctx->conf_node, type);
+	str = fdt_stringlist_get(ctx->fit, ctx->conf_node, type, index, NULL);
+	found = str;
 
 	if (!found && CONFIG_IS_ENABLED(SYSINFO) && !sysinfo_get(&sysinfo)) {
 		int rc;
 		/*
 		 * no string in the property for this index. Check if the
-		 * sysinfo-level code can supply one.
+		 * sysinfo-level code can supply one. Subtract the number of
+		 * strings found in the devicetre node, so that @index numbers
+		 * the options in order from 0, starting with the devicetree
+		 * property and ending with sysinfo.
 		 */
-		rc = sysinfo_get_fit_loadable(sysinfo, index - i - 1, type,
+		rc = sysinfo_get_fit_loadable(sysinfo, index - count, type,
 					      &str);
 		if (rc && rc != -ENOENT)
 			return rc;
-- 
2.30.1.766.gb4fecdf3b7-goog