image: improve UBI image sizing on NAND devices

Many NAND devices use a build recipe with "append-ubi | check-size" to
ensure factory images don't exceed the target flash partition size.
However, UBI reserves space for bad block handling and other operational
overhead, and thus 'check-size' can overestimate the space available by
several MB. In practice, this means a failed check is definitely a failure,
while a passing check is only probably a pass.

Improve the situation by teaching 'Build/append-ubi' to check image sizes
while accounting for UBI reserved blocks. Add new device variable NAND_SIZE
and use with existing IMAGE_SIZE to derate the available space. Each UBI
device reserves 20 PEBs per 1024 PEBs of the entire NAND device for bad
blocks, plus an additional 4 PEBs overhead.

Many devices can transparently enable this check by setting NAND_SIZE based
on their flash storage, and may then remove any unneeded 'check-size'.

Link: http://www.linux-mtd.infradead.org/doc/ubi.html#L_overhead

Suggested-by: Shiji Yang <yangshiji66@qq.com>
Suggested-by: Robert Marko <robimarko@gmail.com>
Signed-off-by: Tony Ambardar <itugrok@yahoo.com>
This commit is contained in:
Tony Ambardar 2023-11-11 04:46:14 -08:00 committed by Hauke Mehrtens
parent cd5e0134b6
commit fc16df9fdd
2 changed files with 6 additions and 1 deletions

View File

@ -133,6 +133,8 @@ define Build/append-md5sum-ascii-salted
rm $@.salted
endef
UBI_NAND_SIZE_LIMIT = $(IMAGE_SIZE) - ($(NAND_SIZE)*20/1024 + 4*$(BLOCKSIZE))
define Build/append-ubi
sh $(TOPDIR)/scripts/ubinize-image.sh \
$(if $(UBOOTENV_IN_UBI),--uboot-env) \
@ -146,6 +148,8 @@ define Build/append-ubi
$(UBINIZE_OPTS)
cat $@.tmp >> $@
rm $@.tmp
$(if $(and $(IMAGE_SIZE),$(NAND_SIZE)),\
$(call Build/check-size,$(UBI_NAND_SIZE_LIMIT)))
endef
define Build/ubinize-kernel

View File

@ -397,6 +397,7 @@ define Device/Init
DEVICE_IMG_NAME = $$(DEVICE_IMG_PREFIX)-$$(1)-$$(2)
FACTORY_IMG_NAME :=
IMAGE_SIZE :=
NAND_SIZE :=
KERNEL_PREFIX = $$(DEVICE_IMG_PREFIX)
KERNEL_SUFFIX := -kernel.bin
KERNEL_INITRAMFS_SUFFIX = $$(KERNEL_SUFFIX)
@ -457,7 +458,7 @@ DEFAULT_DEVICE_VARS := \
DEVICE_DTS_DIR DEVICE_DTS_OVERLAY DEVICE_DTS_LOADADDR \
DEVICE_FDT_NUM DEVICE_IMG_PREFIX SOC BOARD_NAME UIMAGE_MAGIC UIMAGE_NAME \
UIMAGE_TIME SUPPORTED_DEVICES IMAGE_METADATA KERNEL_ENTRY KERNEL_LOADADDR \
UBOOT_PATH IMAGE_SIZE \
UBOOT_PATH IMAGE_SIZE NAND_SIZE \
FACTORY_IMG_NAME FACTORY_SIZE \
DEVICE_PACKAGES DEVICE_COMPAT_VERSION DEVICE_COMPAT_MESSAGE \
DEVICE_VENDOR DEVICE_MODEL DEVICE_VARIANT \