[PATCH 2/3] firmware: Add CONFIG_BUILTIN_FIRMWARE option

[David Woodhouse <dwmw2@infradead.org>]

This allows arbitrary firmware files to be included in the static kernel
where the firmware loader can find them without requiring userspace to
be alive.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
---
 Makefile             |    2 +-
 drivers/base/Kconfig |   12 ++++++++++++
 firmware/Makefile    |   23 +++++++++++++++++++++++
 3 files changed, 36 insertions(+), 1 deletions(-)
 create mode 100644 firmware/Makefile

diff --git a/Makefile b/Makefile
index 20b3235..ac2ab7e 100644
--- a/Makefile
+++ b/Makefile
@@ -450,7 +450,7 @@ scripts: scripts_basic include/config/auto.conf
 
 # Objects we will link into vmlinux / subdirs we need to visit
 init-y		:= init/
-drivers-y	:= drivers/ sound/
+drivers-y	:= drivers/ sound/ firmware/
 net-y		:= net/
 libs-y		:= lib/
 core-y		:= usr/
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index d7da109..687f097 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -34,6 +34,18 @@ config FW_LOADER
 	  require userspace firmware loading support, but a module built outside
 	  the kernel tree does.
 
+config BUILTIN_FIRMWARE
+       string "Firmware blobs to build into the kernel binary"
+       depends on FW_LOADER
+       help
+         This option allows firmware to be built into the kernel, for the cases
+	 where the user either cannot or doesn't want to provide it from
+	 userspace at runtime (for example, when the firmware in question is
+	 required for accessing the boot device, and the user doesn't want to
+	 use an initrd). Multiple files should be separated with spaces, and
+	 the required files should exist under the firmware/ directory in
+	 the source tree.
+
 config DEBUG_DRIVER
 	bool "Driver Core verbose debug messages"
 	depends on DEBUG_KERNEL
diff --git a/firmware/Makefile b/firmware/Makefile
new file mode 100644
index 0000000..184b8ef
--- /dev/null
+++ b/firmware/Makefile
@@ -0,0 +1,23 @@
+#
+# kbuild file for firmware/
+#
+
+FIRMWARE_BINS := $(subst ",,$(CONFIG_BUILTIN_FIRMWARE))
+FIRMWARE_OBJS := $(patsubst %,%.o, $(FIRMWARE_BINS))
+FIRMWARE_SRCS := $(patsubst %,$(obj)/%.c, $(FIRMWARE_BINS))
+
+
+quiet_cmd_fwbin = MK_FW   $@
+      cmd_fwbin = echo '/* File automatically generated */' > $@ ;	 \
+		  echo '\#include <linux/firmware.h>' >> $@ ;		 \
+		  echo 'static const unsigned char fw[] = {' >> $@ ;	 \
+		  od -t x1 -A none -v $(srctree)/$(patsubst %.c,%,$@) | \
+		   sed -e 's/ /, 0x/g' -e 's/^,//' -e 's/$$/,/' >> $@ ; \
+		  echo '};' >> $@ ;					 \
+		  echo 'DECLARE_BUILTIN_FIRMWARE("$(patsubst firmware/%.c,%,$@)",fw);' >> $@
+
+$(FIRMWARE_SRCS): $(obj)/%.c: $(srctree)/$(obj)/%
+	$(call cmd,fwbin)
+
+obj-y := $(FIRMWARE_OBJS)
+
-- 
1.5.4.5


-- 
dwmw2