[kernel] prepare for "late" installation of kernel image

This patch moves the installation of the kernel image from the
targetinstall stage into the images stage.

This is a preparation for the "whole rootfs in initrd in kernel image"
use case, where first the root file system is build and bundled into a
cpio and then linked into the kernel image.

We define some new symbols:
- IMAGE_KERNEL:
  It's automatically activated if the kernel is build. When active the
  kernel is install to "images/linuximage".
- IMAGE_KERNEL_INSTALL_EARLY:
  default "y". When active the kernel is copied to "images/linuximage"
  during targetinstall.
- IMAGE_KERNEL_INSTALL_LATE:
  If selected the kernel is installed later, during the "images" stage.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 24 insertions, 0 deletions

diff --git a/platforms/image_kernel.in b/platforms/image_kernel.in
new file mode 100644
index 000000000..0ac048957
--- /dev/null
+++ b/platforms/image_kernel.in
@@ -0,0 +1,24 @@
+## SECTION=image
+
+menuconfig IMAGE_KERNEL
+	bool
+	prompt "Generate images/linuximage    "
+	depends on KERNEL
+	help
+	  Install the kernel to "platform-FOO/images/linuximage"
+
+if IMAGE_KERNEL
+
+config IMAGE_KERNEL_INSTALL_EARLY
+	bool
+	default !IMAGE_KERNEL_INSTALL_LATE
+	help
+	  If activated the kernel is installed during the kernel's
+	  "targetinstall" stage.
+
+config IMAGE_KERNEL_INSTALL_LATE
+	bool
+	help
+	  Install kernel image during "images".
+
+endif