binman: Add better Makefile debugging

There is a debugging option in the Makefile to allow people to figure out
which u-boot.dtsi files are used in the build. But is it not easy to use
since it only shows files it finds, not those it is looking for. Update it
and update the mention of it to the docs.

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

scripts/Makefile.lib

@@ -165,17 +165,27 @@ cpp_flags      = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(UBOOTINCLUDE)     \
 ld_flags       = $(LDFLAGS) $(ldflags-y)
 
 # Try these files in order to find the U-Boot-specific .dtsi include file
-u_boot_dtsi_options = $(wildcard $(dir $<)$(basename $(notdir $<))-u-boot.dtsi) \
+u_boot_dtsi_options = $(strip $(wildcard $(dir $<)$(basename $(notdir $<))-u-boot.dtsi) \
 	$(wildcard $(dir $<)$(subst $\",,$(CONFIG_SYS_SOC))-u-boot.dtsi) \
 	$(wildcard $(dir $<)$(subst $\",,$(CONFIG_SYS_CPU))-u-boot.dtsi) \
 	$(wildcard $(dir $<)$(subst $\",,$(CONFIG_SYS_VENDOR))-u-boot.dtsi) \
-	$(wildcard $(dir $<)u-boot.dtsi)
+	$(wildcard $(dir $<)u-boot.dtsi))
+
+u_boot_dtsi_options_raw = $(warning Automatic .dtsi inclusion: options: \
+	$(dir $<)$(basename $(notdir $<))-u-boot.dtsi \
+	$(dir $<)$(subst $\",,$(CONFIG_SYS_SOC))-u-boot.dtsi \
+	$(dir $<)$(subst $\",,$(CONFIG_SYS_CPU))-u-boot.dtsi \
+	$(dir $<)$(subst $\",,$(CONFIG_SYS_VENDOR))-u-boot.dtsi \
+	$(dir $<)u-boot.dtsi ... \
+	found: $(if $(u_boot_dtsi_options),"$(u_boot_dtsi_options)",nothing!))
 
 # Uncomment for debugging
-# $(warning u_boot_dtsi_options: $(u_boot_dtsi_options))
+# This shows all the files that were considered and the one that we chose.
+# u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw)
 
 # We use the first match
-u_boot_dtsi = $(notdir $(firstword $(u_boot_dtsi_options)))
+u_boot_dtsi = $(strip $(u_boot_dtsi_options_debug) \
+	$(notdir $(firstword $(u_boot_dtsi_options))))
 
 # Modified for U-Boot
 dtc_cpp_flags  = -Wp,-MD,$(depfile).pre.tmp -nostdinc                    \

tools/binman/README

@@ -446,7 +446,8 @@ If you are having trouble figuring out what is going on, you can uncomment
 the 'warning' line in scripts/Makefile.lib to see what it has found:
 
    # Uncomment for debugging
-   # $(warning binman_dtsi_options: $(binman_dtsi_options))
+   # This shows all the files that were considered and the one that we chose.
+   # u_boot_dtsi_options_debug = $(u_boot_dtsi_options_raw)
 
 
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