[PATCH v2 2/2] firmware_loader: Enable compressed files with EXTRA_FIRMWARE

[Kevin Martin]

The linux-firmware packages on Gentoo, Fedora, Arch, and others
compress the firmware files. This works well with
CONFIG_FW_LOADER_COMPRESS but does not work with CONFIG_EXTRA_FIRMWARE.
This patch allows the build system to decompress firmware files
specified by CONFIG_EXTRA_FIRMWARE. Uncompressed files are used first,
then the compressed files are used.

The patch works by copying or decompressing the specified firmware files
into the build directory, then compiling them in from there. I would
prefer to not copy any uncompressed files, but I have not found a clean
way to do that.

Signed-off-by: Kevin Martin <kevinmbecause@xxxxxxxxx>
---
Changes in v2:
- Changed .gitignore to ignore all firmware files copied into the
directory.
- Fixed a tab.

 drivers/base/firmware_loader/Kconfig            |  5 ++++-
 drivers/base/firmware_loader/builtin/.gitignore |  5 ++++-
 drivers/base/firmware_loader/builtin/Makefile   | 16 ++++++++++++----
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/base/firmware_loader/Kconfig b/drivers/base/firmware_loader/Kconfig
index 5ca00e02f..b7a908bff 100644
--- a/drivers/base/firmware_loader/Kconfig
+++ b/drivers/base/firmware_loader/Kconfig
@@ -76,7 +76,10 @@ config EXTRA_FIRMWARE
 	  image since it combines both GPL and non-GPL work. You should
 	  consult a lawyer of your own before distributing such an image.
 
-	  NOTE: Compressed files are not supported in EXTRA_FIRMWARE.
+	  NOTE: Compressed files are supported by EXTRA_FIRMWARE. The build
+	  system will look for uncompressed files first then fall back to
+	  searching for compressed files in a similar way to
+	  CONFIG_FW_LOADER_COMPRESS.
 
 config EXTRA_FIRMWARE_DIR
 	string "Firmware blobs root directory"
diff --git a/drivers/base/firmware_loader/builtin/.gitignore b/drivers/base/firmware_loader/builtin/.gitignore
index 166f76b43..b3124ee78 100644
--- a/drivers/base/firmware_loader/builtin/.gitignore
+++ b/drivers/base/firmware_loader/builtin/.gitignore
@@ -1,2 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
-*.gen.S
+*
+!.gitignore
+!Makefile
+!main.c
diff --git a/drivers/base/firmware_loader/builtin/Makefile b/drivers/base/firmware_loader/builtin/Makefile
index 6c067dedc..cc60eb441 100644
--- a/drivers/base/firmware_loader/builtin/Makefile
+++ b/drivers/base/firmware_loader/builtin/Makefile
@@ -20,7 +20,7 @@ filechk_fwbin = \
 	echo "    .section .rodata"				;\
 	echo "    .p2align 4"					;\
 	echo "_fw_$(FWSTR)_bin:"				;\
-	echo "    .incbin \"$(fwdir)/$(FWNAME)\""		;\
+	echo "    .incbin \"$(obj)/$(FWNAME)\""			;\
 	echo "_fw_end:"						;\
 	echo "    .section .rodata.str,\"aMS\",$(PROGBITS),1"	;\
 	echo "    .p2align $(ASM_ALIGN)"			;\
@@ -36,7 +36,15 @@ $(obj)/%.gen.S: FORCE
 	$(call filechk,fwbin)
 
 # The .o files depend on the binaries directly; the .S files don't.
-$(addprefix $(obj)/, $(firmware)): $(obj)/%.gen.o: $(fwdir)/%
+$(addprefix $(obj)/, $(firmware)): $(obj)/%.gen.o: $(obj)/%
 
-targets := $(patsubst $(obj)/%,%, \
-                                $(shell find $(obj) -name \*.gen.S 2>/dev/null))
+$(obj)/% : $(fwdir)/% FORCE
+	$(call if_changed,copy)
+
+$(obj)/% : $(fwdir)/%.xz FORCE
+	$(call if_changed,xzdec)
+
+$(obj)/% : $(fwdir)/%.zst FORCE
+	$(call if_changed,zstddec)
+
+targets := $(patsubst %.gen.o, %.gen.S, $(firmware)) $(CONFIG_EXTRA_FIRMWARE)
-- 
2.41.0