use sstate staging to copy update image to deploy directory

Since morty YP uses the sstate also for the deploy directory. Using
this approach old images will be removed from deploy on a new build.
The same process is now used for updates images. As with normal images
the update images won't be cached in the sstate to reduce disk usage.

This change also resolves the issue, that update images are not
recreated after deleting the tmp directory and let bitbake regenerate
all unchanged recipes from sstate.

This is based on the original implementation in image.bbclass.

Signed-off-by: Christian Andersen <c.andersen@kostal.com>
Reviewed-by: Stefano Babic <sbabic@denx.de>

classes/swupdate.bbclass

@@ -64,15 +64,23 @@ def swupdate_getdepends(d):
         depstr += " " + dep + ":do_build"
     return depstr
 
+IMGDEPLOYDIR = "${WORKDIR}/deploy-${PN}-swuimage"
+
 do_swuimage[dirs] = "${TOPDIR}"
-do_swuimage[cleandirs] += "${S}"
+do_swuimage[cleandirs] += "${S} ${IMGDEPLOYDIR}"
 do_swuimage[umask] = "022"
+SSTATETASKS += "do_swuimage"
+SSTATE_SKIP_CREATION_task-swuimage = '1'
+do_swuimage[sstate-inputdirs] = "${IMGDEPLOYDIR}"
+do_swuimage[sstate-outputdirs] = "${DEPLOY_DIR_IMAGE}"
+do_swuimage[stamp-extra-info] = "${MACHINE}"
 
 do_configure[noexec] = "1"
 do_compile[noexec] = "1"
 do_install[noexec] = "1"
+deltask do_populate_sysroot
 do_package[noexec] = "1"
-do_package_qa[noexec] = "1"
+deltask do_package_qa
 do_packagedata[noexec] = "1"
 do_package_write_ipk[noexec] = "1"
 do_package_write_deb[noexec] = "1"
@@ -83,14 +91,6 @@ python () {
     d.appendVarFlag('do_swuimage', 'depends', deps)
 }
 
-do_install () {
-}
-
-do_createlink () {
-    cd ${DEPLOY_DIR_IMAGE}
-    ln -sf ${IMAGE_NAME}.swu ${IMAGE_LINK_NAME}.swu
-}
-
 python do_swuimage () {
     import shutil
 
@@ -115,6 +115,7 @@ python do_swuimage () {
 # If they are not there, additional file can be added
 # by fetching from URLs
     deploydir = d.getVar('DEPLOY_DIR_IMAGE', True)
+    imgdeploydir = d.getVar('IMGDEPLOYDIR', True)
 
     for image in images:
         fstypes = (d.getVarFlag("SWUPDATE_IMAGES_FSTYPES", image, True) or "").split()
@@ -192,12 +193,17 @@ python do_swuimage () {
         else:
             bb.fatal("Unrecognized SWUPDATE_SIGNING mechanism.");
 
-    line = 'for i in ' + ' '.join(list_for_cpio) + '; do echo $i;done | cpio -ov -H crc >' + os.path.join(deploydir,d.getVar('IMAGE_NAME', True) + '.swu')
+    line = 'for i in ' + ' '.join(list_for_cpio) + '; do echo $i;done | cpio -ov -H crc >' + os.path.join(imgdeploydir,d.getVar('IMAGE_NAME', True) + '.swu')
     os.system("cd " + s + ";" + line)
+
+    line = 'ln -sf ' + d.getVar('IMAGE_NAME', True) + '.swu ' + d.getVar('IMAGE_LINK_NAME', True) + '.swu'
+    os.system("cd " + imgdeploydir + "; " + line)
 }
 
 COMPRESSIONTYPES = ""
 PACKAGE_ARCH = "${MACHINE_ARCH}"
 
-addtask do_swuimage after do_unpack after do_prepare_recipe_sysroot before do_install
-addtask do_createlink after do_swuimage before do_install
+INHIBIT_DEFAULT_DEPS = "1"
+EXCLUDE_FROM_WORLD = "1"
+
+addtask do_swuimage after do_unpack after do_prepare_recipe_sysroot before do_build