fdt: Use phandle to distinguish DT nodes with same name

While assigning the sequence number to subsystem instances by reading the
aliases property, only DT nodes names are compared and not the complete
path. This causes a problem when there are two DT nodes with same name but
have different paths.

In arch/arm/dts/k3-am65-main.dtsi there are two USB controllers with the
same device tree node name but different path. When aliases are defined for
these USB controllers then fdtdec_get_alias_seq() fails to pick the correct
instance for a given index.

fdt_path_offset() function is slow and this would effect the U-Boot
startup. To avert the time penalty on all boards, apply this extra check
only when required by using a config option.

Fix it by comparing the phandles of DT nodes after the node names match,
under a config option.

Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Fix whitespace error in Kconfig:
Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/lib/Kconfig b/lib/Kconfig
index 06eb8d07dcf04c0eb4007731d3e2ddc0fcfaf4be..a704568443c9580377f562099c222bd853d24724 100644 (file)
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -699,3 +699,11 @@ config LIB_ELF
          This supports fir 32 bit and 64 bit versions.
 
 endmenu
+
+config PHANDLE_CHECK_SEQ
+       bool "Enable phandle check while getting sequence number"
+       default n
+       help
+         When there are multiple device tree nodes with same name,
+          enable this config option to distinguish them using
+         phandles in fdtdec_get_alias_seq() function.

diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index ee1bd41b081859c49a1e468dee23871b958f5776..0ab7105fef0d4cacfb86637a3976dfed2f83f5e9 100644 (file)
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -500,6 +500,17 @@ int fdtdec_get_alias_seq(const void *blob, const char *base, int offset,
                slash = strrchr(prop, '/');
                if (strcmp(slash + 1, find_name))
                        continue;
+
+               /*
+                * Adding an extra check to distinguish DT nodes with
+                * same name
+                */
+               if (IS_ENABLED(CONFIG_PHANDLE_CHECK_SEQ)) {
+                       if (fdt_get_phandle(blob, offset) !=
+                           fdt_get_phandle(blob, fdt_path_offset(blob, prop)))
+                               continue;
+               }
+
                val = trailing_strtol(name);
                if (val != -1) {
                        *seqp = val;