[U-Boot] U-Boot Makefile question

[Frank Svendsbøe]

Hi Steven,
I recommend you to read the GNU make manual.
See http://www.gnu.org/software/make/manual/

On Tue, Feb 17, 2009 at 2:43 PM, Steven Zedeck <saz at proliphix.com> wrote:
>
> Hi all,
> I am new to u-boot. But I am ramping up pretty fast. My primary issue is
> understanding the Makefile syntax. Is there a good tutorial somewhere that
> explains how u-boot uses the Makefiles and their syntax?
>
> For example, I'm having problems understanding what this means in a
> Makefile:
>
> COBJS-$(CONFIG_HAS_DATAFLASH) += at45.o
> COBJS-$(CONFIG_FLASH_CFI_DRIVER) += cfi_flash.o
> COBJS-$(CONFIG_HAS_DATAFLASH) += dataflash.o
> COBJS-$(CONFIG_FLASH_CFI_LEGACY) += jedec_flash.o
> COBJS-$(CONFIG_MW_EEPROM) += mw_eeprom.o
>
> COBJS   := $(COBJS-y)
> SRCS    := $(COBJS:.o=.c)
> OBJS    := $(addprefix $(obj),$(COBJS))
>
> This is from drivers/mtd/Makefile.
>
> How does COBJS get initially defined upon entry into the Makefile?
>
> Does at45.o get added to the list of objects to be built only if the
> CONFIG_HAS_DATAFLASH flag is set?
>
> What does the "-" sign mean before the "$" ?
>
> What does this mean?  COBJS     := $(COBJS-y)
>
> I'm sorry for the "dumb" questions. Any help with the understanding of
> Makefiles would be greatly appreciated.
>
> Thanks in advance,
> Steve
> --
> View this message in context: http://www.nabble.com/U-Boot-Makefile-question-tp22057574p22057574.html
> Sent from the Uboot - Users mailing list archive at Nabble.com.
>
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot
>