barebox/Documentation/timekeeping.txt
Sascha Hauer a3ffa97f40 rename U-Boot-v2 project to barebox
This has been done with the following script:

find -path ./.git -prune -o -type f -print0 | xargs -0 -r sed -i \
	-e 's/u2boot/barebox/g' \
	-e 's/U2Boot/barebox/g' \
	-e 's/U-boot V2/barebox/g' \
	-e 's/u-boot v2/barebox/g' \
	-e 's/U-Boot V2/barebox/g' \
	-e 's/U-Boot-v2/barebox/g' \
	-e 's/U_BOOT/BAREBOX/g' \
	-e 's/UBOOT/BAREBOX/g' \
	-e 's/uboot/barebox/g' \
	-e 's/u-boot/barebox/g' \
	-e 's/u_boot/barebox/g' \
	-e 's/U-Boot/barebox/g' \
	-e 's/U-boot/barebox/g' \
	-e 's/U-BOOT/barebox/g'

find -path ./.git -prune -o \( -name "*u-boot*" -o -name "*uboot*" -o -name "*u_boot*" \) -print0 | \
	xargs -0 -r rename 's/u[-_]?boot/barebox/'

It needs some manual fixup following in the next patch

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
2009-12-15 10:18:30 +01:00

14 lines
786 B
Text

------------ barebox timekeeping -------------
In barebox we use the clocksource mechanism from the Linux Kernel. This makes
it fairly easy to add timer functionality for a new board or architecture.
Apart from initialization there is only one function required:
clocksource_read(). This function returns the current value of a free running
counter. Other functions like udelay() and get_time_ns() are derived from this
function. The only thing you have to implement is a clocksource driver. See
cpu/arm920t/imx/interrupts.c for an example. clocksource drivers from the
Linux Kernel can be used nearly 1:1, except for the register accesses.
for clocksources the __lshrdi3 symbol is needed. You can find the function for
your architecture in the Linux Kernel or a libc of your choice.