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 uboot 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-govindr...@ti.com>
---

Changes since v1:
 - Added a config option as fdt_path_offset() slows down the u-boot start
   up and would be better to be enabled only when required
 - Added an example case in commit message where the following fix is
   required.

 lib/Kconfig  |  8 ++++++++
 lib/fdtdec.c | 11 +++++++++++
 2 files changed, 19 insertions(+)

diff --git a/lib/Kconfig b/lib/Kconfig
index 8efb154f7344..9813a3a5e0ba 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -685,3 +685,11 @@ 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 ee1bd41b0818..60aa1bd8cf1b 100644
--- 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
+                */
+               #ifdef CONFIG_PHANDLE_CHECK_SEQ
+               if (fdt_get_phandle(blob, offset) !=
+                   fdt_get_phandle(blob, fdt_path_offset(blob, prop)))
+                       continue;
+               #endif
+
                val = trailing_strtol(name);
                if (val != -1) {
                        *seqp = val;
-- 
2.17.1

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