# Use the default kernel version if the Makefile doesn't override it

LINUX_RELEASE?=1

LINUX_VERSION-3.18 = .43
LINUX_VERSION-4.4 = .52

LINUX_KERNEL_HASH-3.18.43 = f61362192b74424539f062a21aa7080f5d66fd8d4cfe2a38f33fab8889bf072c
LINUX_KERNEL_HASH-4.4.52 = 0f1faafdae47da5f29e740ff655f91c2eb13c8cdfc4d039d903176bd56c2ecbb

ifdef KERNEL_PATCHVER
  LINUX_VERSION:=$(KERNEL_PATCHVER)$(strip $(LINUX_VERSION-$(KERNEL_PATCHVER)))
endif

split_version=$(subst ., ,$(1))
merge_version=$(subst $(space),.,$(1))
KERNEL_BASE=$(firstword $(subst -, ,$(LINUX_VERSION)))
KERNEL=$(call merge_version,$(wordlist 1,2,$(call split_version,$(KERNEL_BASE))))
KERNEL_PATCHVER ?= $(KERNEL)

# disable the md5sum check for unknown kernel versions
LINUX_KERNEL_HASH:=$(LINUX_KERNEL_HASH-$(strip $(LINUX_VERSION)))
LINUX_KERNEL_HASH?=x