linux: do not always depend on host-lzop

From: "Yann E. MORIN" <[email protected]>

Hello All!

Here is a small series that makes Linux not always depend on host-lzop, and also cleans up a little bit the linux.mk.

Changes v1 -> v2:
- use simpler sed expression (Peter)
- don't use 'define' to define the function (Arnout)
- initrd and initramfs may also require lzo (Peter)
- move qstrip to the initial assignment (Arnout)
- check the linux config file exists (Peter)

Regards,
Yann E. MORIN.

----------------------------------------------------------------
Yann E. MORIN (3):
packages infra: add function to get a Kconfig option
linux: only depend on host-lzop if needed
linux: check the configuration file exists

 linux/linux.mk       | 15 +++++++++++++--
 package/pkg-utils.mk |  2 ++
 2 files changed, 15 insertions(+), 2 deletions(-)

.-----------------.--------------------.------------------.--------------------.
|  Yann E. MORIN  | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software  Designer | \ / CAMPAIGN     |  ___               |
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From: "Yann E. MORIN" <[email protected]>

We so far have no mean to get the value from a Kconfig option from the .config file of a package (eg. linux, busybox...).

Add a new function that returns the unmangled value of an option. It expect two arguments:
- the Kconfig option name (complete, with leading CONFIG if necessary)
- the .config file to get it from

Note that, if the Kconfig option is a string, the returned value will contain the leading and trailing double-quotes.

---
Changes v1 -> v2:
- use simpler sed expression (Peter)
- use simple assignment, not a define (Arnout)

Note: when we have the Kconfig's 'config' script, we can revisit this to use 'config' instead of our own sed hack.

---
 package/pkg-utils.mk | 2 ++
 1 file changed, 2 insertions(+)

index 91a1981..99fefe6 100644
@@ -52,6 +52,8 @@ define KCONFIG_DISABLE_OPT
 	echo "# $(1) is not set" >> $(2)
 endef
 
+KCONFIG_GET_OPT = $(shell sed -e 's/^$(1)=//p' $(2))
+
 # Helper functions to determine the name of a package and its
 # directory from its makefile directory, using the $(MAKEFILE_LIST)
 # variable provided by make. This is used by the *TARGETS macros to

1.8.1.2

From: "Yann E. MORIN" <[email protected]>

There is no reason to always depend on host-lzop, even when the kernel compression is not LZO.

Since LZO is not the default compression option in the kernel (and there is not sign that will change in the foreseeable future), it will always appear in a config file, whether it is a complete config file or it is only a defconfig.

So, only depend on host-lzop if the LZO compression is enabled in the kernel config file (either the defconfig or the custom config file). This includes:
- kernel compression itself
- initrd compression
- initramfs compression

---
Changes v1 -> v2:
- also select if initrd or initramfs compression is lzo (Peter)

---
 linux/linux.mk | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

index 1a81f77..e8c007d 100644
@@ -41,7 +41,7 @@ endif
 LINUX_PATCHES = $(call qstrip,$(BR2_LINUX_KERNEL_PATCH))
 
 LINUX_INSTALL_IMAGES = YES
-LINUX_DEPENDENCIES  += host-kmod host-lzop
+LINUX_DEPENDENCIES  += host-kmod
 
 ifeq ($(BR2_LINUX_KERNEL_UBOOT_IMAGE),y)
 	LINUX_DEPENDENCIES += host-uboot-tools

@@ -163,7 +163,14 @@ LINUX_POST_PATCH_HOOKS += LINUX_APPLY_PATCHES
 ifeq ($(BR2_LINUX_KERNEL_USE_DEFCONFIG),y)
 KERNEL_SOURCE_CONFIG = $(KERNEL_ARCH_PATH)/configs/$(call qstrip,$(BR2_LINUX_KERNEL_DEFCONFIG))_defconfig
 else ifeq ($(BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG),y)
-KERNEL_SOURCE_CONFIG = $(BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE)
+KERNEL_SOURCE_CONFIG = $(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE))
+endif
+
+ifeq ($(call KCONFIG_GET_OPT,CONFIG_KERNEL_LZO,$(KERNEL_SOURCE_CONFIG)),y)
+LINUX_DEPENDENCIES += host-lzop
+endif
+ifeq ($(call KCONFIG_GET_OPT,CONFIG_RD_LZO,$(KERNEL_SOURCE_CONFIG)),y)
+LINUX_DEPENDENCIES += host-lzop
 endif
 
 define LINUX_CONFIGURE_CMDS

1.8.1.2

From: "Yann E. MORIN" <[email protected]>

... and abort early, before we even use it.

---
 linux/linux.mk | 4 ++++
 1 file changed, 4 insertions(+)

index e8c007d..f4a4bfd 100644
@@ -166,6 +166,10 @@ else ifeq ($(BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG),y)
 KERNEL_SOURCE_CONFIG = $(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE))
 endif
 
+ifeq ($(wildcard $(KERNEL_SOURCE_CONFIG)),)
+$(error Configuration file '$(KERNEL_SOURCE_CONFIG)' not found.)
+endif
+
 ifeq ($(call KCONFIG_GET_OPT,CONFIG_KERNEL_LZO,$(KERNEL_SOURCE_CONFIG)),y)
 LINUX_DEPENDENCIES += host-lzop
 endif

1.8.1.2

Dear Yann E. MORIN,

Series applied, thanks.

Thomas

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

Hello,

And I've reverted it because it simply cannot work with internal defconfig of the kernel, since they are only available after the kernel has been extracted, which is too late to declare whether we need the host-lzop dependency or not.

Best regards,

Thomas

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com