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 ---
Changes since v2: - changed #ifdef to if(IS_ENABLED()) - corrected errors in commit description
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..0ab7105fef0d 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 + */ + 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;