linux: allow specification of a custom Git repository as a source

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

linux/Config.in

@@ -47,6 +47,12 @@ config BR2_LINUX_KERNEL_CUSTOM_TARBALL
 	  This option allows to specify the http or ftp location of a
 	  specific kernel source tarball
 
+config BR2_LINUX_KERNEL_CUSTOM_GIT
+	bool "Custom Git tree"
+	help
+	  This option allows Buildroot to get the Linux kernel source
+	  code from a Git repository.
+
 endchoice
 
 config BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE
@@ -58,12 +64,21 @@ config BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION
 	string "URL of custom kernel tarball"
 	depends on BR2_LINUX_KERNEL_CUSTOM_TARBALL
 
+config BR2_LINUX_KERNEL_CUSTOM_GIT_REPO_URL
+	string "URL of custom Git repository"
+	depends on BR2_LINUX_KERNEL_CUSTOM_GIT
+
+config BR2_LINUX_KERNEL_CUSTOM_GIT_VERSION
+	string "Custom Git version"
+	depends on BR2_LINUX_KERNEL_CUSTOM_GIT
+
 config BR2_LINUX_KERNEL_VERSION
 	string
 	default "2.6.39.3" if BR2_LINUX_KERNEL_2_6_39
 	default BR2_DEFAULT_KERNEL_HEADERS if BR2_LINUX_KERNEL_SAME_AS_HEADERS
 	default BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE if BR2_LINUX_KERNEL_CUSTOM_VERSION
 	default "custom" if BR2_LINUX_KERNEL_CUSTOM_TARBALL
+	default $BR2_LINUX_KERNEL_CUSTOM_GIT_VERSION if BR2_LINUX_KERNEL_CUSTOM_GIT
 
 #
 # Patch selection

linux/linux.mk

@@ -10,6 +10,9 @@ ifeq ($(LINUX_VERSION),custom)
 LINUX_TARBALL = $(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION))
 LINUX_SITE = $(dir $(LINUX_TARBALL))
 LINUX_SOURCE = $(notdir $(LINUX_TARBALL))
+else ifeq ($(BR2_LINUX_KERNEL_CUSTOM_GIT),y)
+LINUX_SITE = $(call qstrip,$(BR2_LINUX_KERNEL_CUSTOM_GIT_REPO_URL))
+LINUX_SITE_METHOD = git
 else
 LINUX_SOURCE = linux-$(LINUX_VERSION).tar.bz2
 LINUX_SITE = $(BR2_KERNEL_MIRROR)/linux/kernel/v2.6/