Commit graph

4388 commits

Author SHA1 Message Date
pekon gupta
2eda892f00 mtd: nand: omap: move omap_elm.h from arch/arm/include/asm to drivers/mtd/nand
omap_elm.h is a generic header used by OMAP ELM driver for all TI platfoms.
Hence this file should be present in generic folder instead of architecture
specific include folder.
Build tested using: ./MAKEALL -s am33xx -s omap3 -s omap4 -s omap5

Signed-off-by: Pekon Gupta <pekon@ti.com>
2014-03-04 17:23:54 -06:00
pekon gupta
6aff050988 mtd: nand: omap: move omap_gpmc.h from arch/arm/include/asm to drivers/mtd/nand
omap_gpmc.h is a generic header used by OMAP NAND driver for all TI platfoms.
Hence this file should be present in generic folder instead of architecture
specific include folder.
Build tested using: ./MAKEALL -s am33xx -s omap3 -s omap4 -s omap5

Signed-off-by: Pekon Gupta <pekon@ti.com>
2014-03-04 17:23:54 -06:00
pekon gupta
51d192c40d mtd: nand: omap: merge duplicate GPMC data from different arch-xx headers into common omap_gpmc.h
Each SoC platform (AM33xx, OMAP3, OMAP4, OMAP5) has its own copy of GPMC related
defines and declarations scattered in SoC platform specific header files
like include/asm/arch-xx/cpu.h
However, GPMC hardware remains same across all platforms thus this patch merges
GPMC data scattered across different arch-xx specific header files into single
header file include/asm/arch/omap_gpmc.h

Build tested using: ./MAKEALL -s am33xx -s omap3 -s omap4 -s omap5

Signed-off-by: Pekon Gupta <pekon@ti.com>
2014-03-04 17:23:54 -06:00
pekon gupta
a7e36fc95f mtd: nand: omap: remove unused #defines from common omap_gpmc.h
OMAP NAND driver can detect Page-size and OOB-size of NAND device from ONFI
params or nand_id[] table. And based on that it defines ECC layout.
This patch
1) removes following board configs used for defining NAND ECC layout
	- GPMC_NAND_ECC_LP_x16_LAYOUT (for large page x16 NAND)
	- GPMC_NAND_ECC_LP_x8_LAYOUT  (for large page x8 NAND)
	- GPMC_NAND_ECC_SP_x16_LAYOUT (for small page x16 NAND)
	- GPMC_NAND_ECC_SP_x8_LAYOUT  (for small page x8 NAND)

2) removes unused #defines in common omap_gpmc.h depending on above configs

Build tested using: ./MAKEALL -s am33xx -s omap3 -s omap4 -s omap5

Signed-off-by: Pekon Gupta <pekon@ti.com>
2014-03-04 17:23:54 -06:00
pekon gupta
50899183c9 mtd: nand: omap: remove redundant platform specific header: arch-xx/omap_gpmc.h
Currently there are two sets of omap_gpmc.h header files
(a) arch/arm/include/asm/omap_gpmc.h
 common header file for all platforms, containing defines and declarations used
 by GPMC NAND driver.

(b) arch/arm/include/asm/arch-xx/omap_gpmc.h
 SoC platform specific header file containing defines like ECC layout.

This patch removes platform specific arch-xx/omap_gpmc.c because:
 - GPMC hardware engine is common for all SoC platforms hence only (a) is enough
 - ECC layout is now defined in omap_nand.c driver itself based on ecc-scheme
   selected. Hence all ECC layout declarations in (b) are redundant.

Build tested using: ./MAKEALL -s am33xx -s omap3 -s omap4 -s omap5

Signed-off-by: Pekon Gupta <pekon@ti.com>
2014-03-04 17:23:04 -06:00
pekon gupta
f5f1f614bd mtd: nand: omap: optimize chip->ecc.hwctl() for H/W ECC schemes
chip->ecc.hwctl() is used for preparing the H/W controller before read/write
NAND accesses (like assigning data-buf, enabling ECC scheme configs, etc.)

Though all ECC schemes in OMAP NAND driver use GPMC controller for generating
ECC syndrome (for both Read/Write accesses). But but in current code
HAM1_ECC and BCHx_ECC schemes implement individual function to achieve this.
This patch
(1) removes omap_hwecc_init() and omap_hwecc_init_bch()
as chip->ecc.hwctl will re-initializeGPMC before every read/write call.
omap_hwecc_init_bch() -> omap_enable_ecc_bch()

(2) merges the GPMC configuration code for all ECC schemes into
single omap_enable_hwecc(), thus adding scalability for future ECC schemes.
omap_enable_hwecc() + omap_enable_ecc_bch() -> omap_enable_hwecc()

Signed-off-by: Pekon Gupta <pekon@ti.com>
2014-03-03 20:09:03 -06:00
Tom Rini
eeb72e6761 Merge branch 'master' of git://git.denx.de/u-boot-arm
Conflicts:
	arch/arm/cpu/armv7/config.mk
	board/ti/am43xx/mux.c
	include/configs/am43xx_evm.h

Signed-off-by: Tom Rini <trini@ti.com>
2014-02-26 16:49:58 -05:00
Tom Rini
1551df35f2 arm: Switch to -mno-unaligned-access when supported by the compiler
When we tell the compiler to optimize for ARMv7 (and ARMv6 for that
matter) it assumes a default of SCTRL.A being cleared and unaligned
accesses being allowed and fast at the hardware level.  We set this bit
and must pass along -mno-unaligned-access so that the compiler will
still breakdown accesses and not trigger a data abort.

To better help understand the requirements of the project with respect
to unaligned memory access, the
Documentation/unaligned-memory-access.txt file has been added as
doc/README.unaligned-memory-access.txt and is taken from the v3.14-rc1
tag of the kernel.

Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Cc: Mans Rullgard <mans@mansr.com>
Signed-off-by: Tom Rini <trini@ti.com>
2014-02-26 21:19:32 +01:00
Albert ARIBAUD
b60eff31f3 arm: remove unneeded symbol offsets and _TEXT_BASE
Remove the last uses of symbol offsets in ARM U-Boot.
Remove some needless uses of _TEXT_BASE.
Remove all _TEXT_BASE definitions.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
2014-02-26 21:18:12 +01:00
Albert ARIBAUD
d0b5d9da5d arm: make _end compiler-generated
This prevents references to _end from generating absolute
relocation records.

This change is binary invariant for ARM targets.

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
2014-02-26 21:18:09 +01:00
Tom Rini
a7e8c15f71 Merge branch 'master' of git://git.denx.de/u-boot-mpc85xx
With this, fixup a trivial build error of get_effective_memsize needing
to be updated in the new board/freescale/p1010rdb/spl.c

Signed-off-by: Tom Rini <trini@ti.com>
2014-02-25 13:55:49 -05:00
Masahiro Yamada
4c48cfb58b arm: omap: delete unincluded omap-common/config.mk
arch/arm/cpu/armv7/omap-common/config.mk is never included
because "omap-common" is not SoC name.

If we want to add OMAP-specific compiler flags,
they must be added to omap3/config.mk, omap4/config.mk, omap5/config.mk.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Tom Rini <trini@ti.com>
2014-02-25 11:01:29 -05:00
Masahiro Yamada
630d23455b kbuild: refactor more IMX image rules
This commit avoids generating ./SPL twice.
  - Fist time descending to spl/
  - Second time as a prerequisite of u-boot-with-spl.imx,
    u-boot-with-nand-spl.imx.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-25 11:01:29 -05:00
Masahiro Yamada
4e0c8abcdd kbuild: use shorten logs for IMX images
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-25 11:01:29 -05:00
Masahiro Yamada
04a34c96b1 kbuild: use shorten logs for misc targets
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-25 11:01:29 -05:00
Masahiro Yamada
ad0fed46b9 kbuild: use shorten log for linking u-boot
Move sandbox-specific link rule to arch/sandbox/config.mk.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-25 11:01:29 -05:00
Masahiro Yamada
9bf215b035 kbuild: use shorten logs for mkimage rules
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-25 11:01:29 -05:00
Masahiro Yamada
95ddcd68ab kbuild: rename OBJCFLAGS to OBJCOPYFLAGS
Rename OBJCFLAGS to OBJCOPYFLAGS beforehand to use
"cmd_objcopy" in scripts/Makefile.lib in an upcoming commit.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-25 11:01:28 -05:00
Shengzhou Liu
35c471e509 powerpc/t208x: some update to support t2081
- fix serdes definition for t2081.
- fix clock speed for t2081.
- update ids, as CONFIG_FSL_SATA_V2 is needed only for t2080,
  T2081 has no SATA.

Signed-off-by: Shengzhou Liu <Shengzhou.Liu@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>
2014-02-24 15:22:36 -08:00
Masahiro Yamada
f55e911ff4 arm: delete unused macro CONFIG_ARCH_DEVICE_TREE
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Tom Warren <twarren@nvidia.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Rajeshwari Birje <rajeshwari.s@samsung.com>
Cc: Inderpal Singh <inderpal.singh@linaro.org>
2014-02-24 10:56:33 -05:00
Albert ARIBAUD
fae56934a0 Merge branch 'u-boot-ti/master' into 'u-boot-arm/master' 2014-02-24 10:29:59 +01:00
Darwin Rambo
989ce04999 arch: bcm281xx: Initial commit of bcm281xx architecture code
Add bcm281xx architecture support code including a clock framework and
chip reset.  Define register block base addresses for the bcm281xx
architecture and create an empty gpio header file required when
CONFIG_CMD_GPIO is set.

Signed-off-by: Darwin Rambo <drambo@broadcom.com>
Reviewed-by: Steve Rae <srae@broadcom.com>
Reviewed-by: Tim Kryger <tkryger@linaro.org>
2014-02-22 19:30:24 +01:00
Darwin Rambo
b3134fce89 arch: kona: Initial commit of kona-common architecture code
The Kona architecture is present on a number of Broadcom mobile SoCs
including the bcm281xx family of chips.

Signed-off-by: Darwin Rambo <drambo@broadcom.com>
Reviewed-by: Steve Rae <srae@broadcom.com>
Reviewed-by: Tim Kryger <tkryger@linaro.org>
2014-02-22 19:30:18 +01:00
Måns Rullgård
11f2968706 ti814x: Fix illegal use of FP ops in clock_ti814x.c
The function pll_sigma_delta_val uses "float" data which is not correct.
The exact "why" of this mangling is lost to history, but this changes us
to equivalent non-FP math to get the same results.

Reported-by: Wolfgang Denk <wd@denx.de>
Acked-by: Matt Porter <mporter@linaro.org>
2014-02-21 14:03:44 -05:00
Nishanth Menon
82da4410f8 DRA7: fix ABB efuse offset for OPP_NOM
commit 194dd74ad9
(DRA7: add ABB setup for MPU voltage domain)

Made an offset typo error by using 0x4A003B24 as the efuse offset
for OPP_NOM. As per TI documentation, 0x4A003B24 is for OPP_OD, and
0x4A003B20 is for OPP_NOM. Fix the same.

Reported-by: Praveen Rao <prao@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
2014-02-21 13:55:41 -05:00
Janne Grunau
6e2192a3d8 ARM: OMAP4: fix DDR timings for OMAP4430 ES2.0
DDR timings were broken since 47abc3df70
for PandaBoard EA1.

Signed-off-by: Janne Grunau <j@jannau.net>
2014-02-21 13:55:41 -05:00
Dave Gerlach
cd8341b7eb ARM: AM43xx: GP-EVM: Correct GPIO used for VTT regulator control
Schematic indicates GPIO5_7 is to be used for VTT regulator control
rather than GPIO0_21 so modify enable_vtt_regulator to reflect this.
Without this some boards will experience DDR3 corruption and fail to
boot.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
[trini: Rework patch against mainline]
Signed-off-by: Tom Rini <trini@ti.com>
2014-02-21 13:55:40 -05:00
Hannes Petermaier
072cefe07d Add support for B&R KWB Motherboard
Adds support for Bernecker & Rainer Industrieelektronik GmbH KWB
Motherboard, using TI's AM3352 SoC.

Most of code is derived from TI's AM335x_EVM

Signed-off-by: Hannes Petermaier <oe5hpm@oevsv.at>
Cc: trini@ti.com
2014-02-21 13:55:40 -05:00
Lothar Felten
da4105dfcd am335x: Initial support for Silica Pengwyn board
This patch add support for the Silica Pengwyn board [1]
The board is based on a TI AM3354 CPU [2]
All jumpers removed it will boot from the SDcard, the console is on
UART1 accessible via the FDTI -> USB. The on board NAND flash is
supported and can act as boot medium, depending on jumper settings.
USB Host, USB Device and Ethernet are also provided but untested.

[1]
http://www.silica.com/product/silica-pengwyn-board.html
[2]
http://www.ti.com/product/am3354

Signed-off-by: Lothar Felten <lothar.felten@gmail.com>
[trini: Move CONFIG_BOARD_LATE_INIT into am335x_evm.h, drop unused
spi0_pin_mux from Pengwyn support]
Signed-off-by: Tom Rini <trini@ti.com>
2014-02-21 13:54:57 -05:00
York Sun
e38661634b common: Add get_effective_memsize() to memsize.c
This function has been around for powerpc. It is used for systems with
memory more than CONFIG_MAX_MEM_MAPPED. In case of non-contiguous memory,
this feature can limit U-boot to one block without going over the limit.

Signed-off-by: York Sun <yorksun@freescale.com>
Acked-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
2014-02-21 11:06:13 -05:00
Tom Rini
4c89a369c7 Merge branch 'master' of git://git.denx.de/u-boot-spi 2014-02-21 08:00:22 -05:00
Alexey Brodkin
36ae5cd2a8 arc: fix relocation for big-endian target
In case of little-endian ARC700 instructions (which may include target
address) are encoded as middle-endian. That's why it's required to swap
bytes after read and ten right before write back.

But in case of big-endian ARC700 instructions are encoded as a plain
big-endian. Thus no need for byte swapping.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Cc: Francois Bedard <fbedard@synopsys.com>
Cc: Tom Rini <trini@ti.com>
cc: Noam Camus <noamc@ezchip.com>
2014-02-21 07:56:42 -05:00
Tom Rini
6853e6aa77 Merge branch 'master' of git://git.denx.de/u-boot-arm 2014-02-20 12:18:59 -05:00
Tom Rini
130fbeb1c5 blackfin: Add <asm/clock.h> to numerous drivers
With d6a320d we moved some clock externs out of blackfin_local.h and
into clock.h but now need to include <asm/clock.h> in more drivers to
avoid warnings.

Cc: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Tom Rini <trini@ti.com>
2014-02-20 12:00:27 -05:00
Masahiro Yamada
3241e3d08c venice2: move device tree to fix build error
Commit 5ab502cb gathered all device tree sources
to arch/$(ARCH)/dts/.
So tegra124-venice2.dts also must go to arch/arm/dts directory
to build venice2 board.

(Commit 5ab502cb had been posted before venice2 board support
was merged. So an unvisible conflict happened.)

Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@ti.com>
2014-02-20 12:00:20 -05:00
Albert ARIBAUD
3e11350255 Merge branch 'u-boot/master' into 'u-boot-arm/master'
Conflicts:
	Makefile
	drivers/net/npe/Makefile

These two conflicts arise from commit 0b2d3f20
("ARM: NET: Remove the IXP NPE ethernet driver") and are
resolved by deleting the drivers/net/npe/Makefile file
and removing the CONFIG_IXP4XX_NPE line from Makefile.
2014-02-20 13:16:05 +01:00
Alexey Brodkin
39abd65c34 arc: remove "hardware.h"
This file was only required for compilation of designware_i2c driver.
Since explicit inclusion of "hardware.h" is now removed from the driver
we may safely remove this empty header as well.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Cc: Tom Rini <trini@ti.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Stefan Roese <sr@denx.de>
Cc: Vipin Kumar <vipin.kumar@st.com>
Cc: Armando Visconti <armando.visconti@st.com>
2014-02-20 06:49:19 +01:00
Alexey Brodkin
f93f589ca2 spear: move CONFIG_SYS_I2C_BASE from arch-spear/hardware to board configs
Having CONFIG_SYS_I2C_BASE requires DW I2C driver to explicitly include
<arch/hardware.h> which other platforms may not have at all.

It's always good to have a driver platform-independent.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

Cc: Tom Rini <trini@ti.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Stefan Roese <sr@denx.de>
Cc: Vipin Kumar <vipin.kumar@st.com>
Cc: Armando Visconti <armando.visconti@st.com>
2014-02-20 06:49:02 +01:00
Sonic Zhang
86bdd70a09 blackfin: rename bfin-twi_i2c driver to adi_i2c
The ADI twi peripheral is not binding to Blackfin processor only.
Change to a generic name.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
2014-02-20 06:46:56 +01:00
Sonic Zhang
d6a320d5bb blackfin: add spi and i2c specific get clock functions
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
2014-02-20 06:46:56 +01:00
Masahiro Yamada
2aa43f70cf kbuild,tegra124: add dummy obj- for Kbuild
In Kbuild, every makefile must have non-empty obj- or obj-y.
Otherwise, built-in.o will not be created and the link stage
will fail.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-19 15:43:46 -05:00
Masahiro Yamada
ca53735a4c Move CONFIG_DISPLAY_CPUINFO to Makefile
If the whole code is surrounded by #ifdef(CONFIG_ ) .. #endif,
it should be moved to Makefile.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-19 11:10:05 -05:00
Masahiro Yamada
365475e6d1 Move #ifdef(CONFIG_DISPLAY_CPUINFO) from caller to callee
- When CONFIG_DISPLAY_CPUINFO is not enabled,
   print_cpuinfo() should be defined as an empty function
   in a header, include/common.h

 - Remove #ifdef CONFIG_DISPLAY_CPUINFO .. #endif
   from caller, common/board_f.c and arch/arm/lib/board.c

 - Remove redundant prototypes in arch/arm/lib/board.c,
   arch/arm/include/asm/arch-am33x/sys_proto.h and
   board/nokia/rx51/rx51.h, keeping the one in include/common.h

 - Add #ifdef CONFIG_DISPLAY_CPUINFO to the func definition
   where it is missing

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-19 11:10:05 -05:00
Masahiro Yamada
3284c8b8ca dts: generate multiple device tree blobs
It is convenient to have all device trees on the same SoC compiled.
It allows for later easy repackaging without the need to re-run
the make file.

  - Build device trees with the same SoC under arch/$(ARCH)/dts

  - Copy the one specified by CONFIG_DEFAULT_DEVICE_TREE or
    DEVICE_TREE=... to dts/dt.dtb

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-19 11:10:05 -05:00
Masahiro Yamada
5ab502cb89 dts: move device tree sources to arch/$(ARCH)/dts/
Unlike Linux Kernel, U-Boot historically had *.dts files under
board/$(VENDOR)/dts/ and *.dtsi files under arch/$(ARCH)/dts/.

I think arch/$(ARCH)/dts dicretory is a better location
to store both *.dts and *.dtsi files.

For example, before this commit, board/xilinx/dts directory
had both Microblaze dts (microblaze-generic.dts) and
ARM dts (zynq-*.dts), which are totally unrelated.

This commit moves *.dts to arch/$(ARCH)/dts/ directories,
allowing us to describe nicely mutiple DTBs generation in the next commit.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-19 11:10:05 -05:00
Masahiro Yamada
6ab6b2afa0 dts: re-write dts/Makefile more simply with Kbuild
Useful rules in scripts/Makefile.lib allows us to easily
generate a device tree blob and wrap it in assembly code.

We do not need to parse a linker script to get output format and arch.

This commit deletes ./u-boot.dtb since it is a copy of dts/dt.dtb.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-19 11:10:05 -05:00
Masahiro Yamada
efcf861931 kbuild: use scripts/Makefile.clean
This commit refactors cleaning targets such as
clean, clobber, mrpropper, distclean
with scripts/Makefile.clean.

By using scripts/Makefile.clean, we can recursively descend
into subdirectories and delete generated files there.

We do not need add a big list of generated files
to the "clean" target.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-19 11:10:04 -05:00
Masahiro Yamada
6825a95b0b kbuild: use Linux Kernel build scripts
Now we are ready to switch over to real Kbuild.

This commit disables temporary scripts:
  scripts/{Makefile.build.tmp, Makefile.host.tmp}
and enables real Kbuild scripts:
  scripts/{Makefile.build,Makefile.host,Makefile.lib}.

This switch is triggered by the line in scripts/Kbuild.include
  -build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build.tmp obj
  +build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj

We need to adjust some build scripts for U-Boot.
But smaller amount of modification is preferable.

Additionally, we need to fix compiler flags which are
locally added or removed.

In Kbuild, it is not allowed to change CFLAGS locally.
Instead, ccflags-y, asflags-y, cppflags-y,
CFLAGS_$(basetarget).o, CFLAGS_REMOVE_$(basetarget).o
are prepared for that purpose.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>
2014-02-19 11:07:50 -05:00
Masahiro Yamada
7c8278a866 kbuild: add dummy obj-y to create built-in.o
We are going to switch over to Kbuild in upcoming commits.

Each makefile must have non-empty obj- or obj-y
to generate built-in.o on Kbuild.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-02-19 11:07:50 -05:00
Masahiro Yamada
9e4140329e kbuild: change out-of-tree build
This commit changes the working directory
where the build process occurs.

Before this commit, build process occurred under the source
tree for both in-tree and out-of-tree build.

That's why we needed to add $(obj) prefix to all generated
files in makefiles like follows:
  $(obj)u-boot.bin:  $(obj)u-boot

Here, $(obj) is empty for in-tree build, whereas it points
to the output directory for out-of-tree build.

And our old build system changes the current working directory
with "make -C <sub-dir>" syntax when descending into the
sub-directories.

On the other hand, Kbuild uses a different idea
to handle out-of-tree build and directory descending.

The build process of Kbuild always occurs under the output tree.
When "O=dir/to/store/output/files" is given, the build system
changes the current working directory to that directory and
restarts the make.

Kbuild uses "make -f $(srctree)/scripts/Makefile.build obj=<sub-dir>"
syntax for descending into sub-directories.
(We can write it like "make $(obj)=<sub-dir>" with a shorthand.)
This means the current working directory is always the top
of the output directory.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>
2014-02-19 11:07:50 -05:00