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

LINUX_RELEASE?=1

LINUX_VERSION-3.18 = .71
LINUX_VERSION-4.4 = .91
LINUX_VERSION-4.9 = .53

LINUX_KERNEL_HASH-3.18.71 = 5abc9778ad44ce02ed6c8ab52ece8a21c6d20d21f6ed8a19287b4a38a50c1240
LINUX_KERNEL_HASH-4.4.91 = cb9d2b8c1afe58414de5bc7d65429cc9f5f37c80fc229d0e83c55c5c3c254ffb
LINUX_KERNEL_HASH-4.9.53 = 32915a33bb0b993b779257748f89f31418992edba53acbe1160cb0f8ef3cb324

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