Hi Aswath, On Wed, 2 Dec 2020 at 08:42, Aswath Govindraju <a-govindr...@ti.com> wrote: > > 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.
U-Boot > 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 (IS_ENABLED(CONFIG... (did you not get a warning from patman on that?) > + 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 > Regards, SImon