Define CFG_DDR_SDRAM_CLK_CNTL for the MPC8349E-mITX and MPC8349E-mITX-GP.
This allows ddr->sdram_clk_cntl to be properly initialized. This is necessary
on some ITX boards, notably those with a revision 3.1 CPU.
Also change spd_sdram() in cpu/mpc83xx/spd_sdram.c to not write anything into
ddr->sdram_clk_cntl if CFG_DDR_SDRAM_CLK_CNTL is not defined.
Signed-off-by: Timur Tabi <timur@freescale.com>
Acked-by: Michael Benedict <MBenedict@twacs.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Clarified that conversion is to DRAM clocks rather than platform clocks.
Made function static to spd_sdram.c.
Signed-off-by: James Yang <James.Yang@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Changed the code to read the registers and calculate the clock
rates, rather than using a "switch" statement.
Idea from Andrew Klossner <andrew@cesa.opbu.xerox.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
e500v2 and newer cores support 1G page sizes.
Signed-off-by: Ed Swarthout <Ed.Swarthout@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
Enable single-bit error counter when memory was cleared by ddr controller.
Signed-off-by: Ed Swarthout <Ed.Swarthout@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
Some device trees have a mac-address property, some have local-mac-address,
and some have both. To support all of these device trees, ftp_cpu_setup()
should write the MAC address to mac-address and local-mac-address, if they
exist.
Signed-off-by: Timur Tabi <timur@freescale.com>
* Cleaned up the TSR[WIS] clearing
* Cleaned up DMA initialization
Signed-off-by: Ed Swarthout <Ed.Swarthout@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Acked-by: Andy Fleming <afleming@freescale.com>
Recognize new SVR values, and add a few register definitions
Signed-off-by: Ed Swarthout <Ed.Swarthout@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Acked-by: Andy Fleming <afleming@freescale.com>
The following patch fixes the e500 v2 core reset bug.
For e500 v2 core, a new reset control register is added to reset the
processor.
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Remove the fixed TLB and LAW entry nubmer. Use actually TLB and LAW
entry number to control the loop. This can reduce the potential risk
for the 85xx processor increasing its TLB adn LAW entry number.
Signed-off-by: Swarthout Edward <swarthout@freescale.com>
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Board code can now request the generic setup code rather than having to
copy-and-paste it for themselves. Boards should be converted to use this
once they're tested with it.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Rather than misleadingly define PVR_83xx as the specific type of 83xx
being built for, the PVR of each core revision is defined. checkcpu() now
prints the core that it detects, rather than aborting if it doesn't find
what it thinks it wants.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Some device trees have a mac-address property, some have local-mac-address,
and some have both. To support all of these device trees, ftp_cpu_setup()
should write the MAC address to mac-address and local-mac-address, if they
exist.
Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Now 405EZ ports also show upon bootup from which boot device
they are configured to boot:
U-Boot 1.2.0-gd3832e8f-dirty (Apr 18 2007 - 07:47:05)
CPU: AMCC PowerPC 405EZ Rev. A at 199.999 MHz (PLB=133, OPB=66, EBC=66 MHz)
Bootstrap Option E - Boot ROM Location EBC (32 bits)
16 kB I-Cache 16 kB D-Cache
Board: Acadia - AMCC PPC405EZ Evaluation Board
Signed-off-by: Stefan Roese <sr@denx.de>
Use "setter" functions instead of flags, cleaner and more flexible.
It also fixes the problem noted by Timur Tabi that the ethernet MAC
addresses were all being set incorrectly to the same MAC address.
Driver for the Atmel MCI controller (MMC interface) for AT32AP CPUs.
The AT91 ARM-based CPUs use basically the same hardware, so it should
be possible to share this driver, but no effort has been made so far.
Hardware documentation can be found in the AT32AP7000 data sheet,
which can be downloaded from
http://www.atmel.com/dyn/products/datasheets.asp?family_id=682
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Implement functions for configuring the mmci pins, as well as
functions for getting the clock rate of the mmci controller.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Implement functions for configuring the macb0 and macb1 pins, as
well as functions for getting the clock rate of the various
busses the macb ethernet controllers are connected to.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Relocate the u-boot image into SDRAM like everyone else does. This
means that we can handle much larger .data and .bss than we used to.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Rewrite the resource management code (i.e. I/O memory, clock gating,
gpio) so it doesn't depend on any global state. This is necessary
because this code is heavily used before relocation to RAM, so we
can't write to any global variables.
As an added bonus, this makes u-boot's memory footprint a bit smaller,
although some functionality has been left out; all clocks are enabled
all the time, and there's no checking for gpio line conflicts.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Split the avr32 initialization code into a function to run before
relocation, board_init_f and a function to run after relocation,
board_init_r. For now, board_init_f simply calls board_init_r
at the end.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
There are a few bugs in the cpu/mpc83xx/spd_sdram.c
the first bug is that the picos_to_clk routine introduces a huge
rounding error in 83xx.
the second bug is that the mode register write recovery field is
tWR-1, not tWR >> 1.
This patch fixes changes the i2c_init(...) function to use the function
get_OPB_freq() rather than calculating the OPB speed by
sysInfo.freqPLB/sysInfo.pllOpbDiv. The get_OPB_freq() function is
specific per processor. The prior method was not and so was calculating
the wrong speed for some PPC4xx processors.
Signed-off-by: Jeffrey Mann <mannj@embeddedplanet.com>
Signed-off-by: Stefan Roese <sr@denx.de>
Move the 8641HPCN's PIXIS code to the new directory
board/freescale/common/ as it will be shared by
future boards not in the same processor family.
Write a "pixis_reset" command that utilizes the FPGA
reset sequencer to support alternate soft-reset options
such as using the "alternate" flash bank, enabling
the watch dog, or choosing different CPU frequencies.
Add documentation for the pixis_reset to README.mpc8641hpcn.
Signed-off-by: Haiying Wang <haiying.wang@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Fix a bug in the auto calibration routine. This driver now runs
more reliable with the tested modules. It's also tested with
167MHz PLB frequency (667MHz DDR2 frequency) on the Katmai.
Signed-off-by: Stefan Roese <sr@denx.de>
This patch adds some 4xx GPIO functions. It also moves some of the
common code and defines into a common 4xx GPIO header file.
Signed-off-by: Stefan Roese <sr@denx.de>
Prevent false interrupt from hanging Linux as MSR[EE] is set
to enable interrupts by changing the PIC out of the default
pass through mode into mixed mode.
Signed-off-by: Haiying Wang <haiying.wang@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Without this patch, I am unable to get to the prompt on rev 2 silicon.
Only set ddrioovcr for rev1.
Signed-off-by: Ed Swarthout<ed.swarthout@freescale.com>
Signed-off-by: Jon Loeliger <jdl@freescale.com>
This patch adds support for the new AMCC 405EZ PPC. It is in
preparation for the AMCC Acadia board support.
Please note that this Acadia/405EZ support is still in a beta stage.
Still lot's of cleanup needed but we need a preliminary release now.
Signed-off-by: Stefan Roese <sr@denx.de>
timer support
interrupt controller support
flash support
ethernet support
cache support
board information support
env support
booting image support
adding support for Xilinx ML401
timer support
interrupt controller support
flash support
ethernet support
cache support
board information support
env support
booting image support
adding support for Xilinx ML401
The AMCC Luan now uses the common 440SP(e) DDR SPD code for DDR
inititializition. This includes DDR auto calibration and support
for different DIMM modules, instead of the fixed setup used in
the earlier version.
This patch also enables the cache in FLASH for the startup
phase of U-Boot (while running from FLASH). After relocating to
SDRAM the cache is disabled again. This will speed up the boot
process, especially the SDRAM setup, since there are some loops
for memory testing (auto calibration).
Signed-off-by: Stefan Roese <sr@denx.de>
This patch fixes a problem that occurs when 2 DIMM's are
used. This problem was first spotted and fixed by Gerald Jackson
<gerald.jackson@reaonixsecurity.com> but this patch fixes the
problem in a little more clever way.
This patch also adds the nice functionality to dynamically
create the TLB entries for the SDRAM (tlb.c). So we should
never run into such problems with wrong (too short) TLB
initialization again on these platforms.
As this feature is new to the "old" 44x SPD DDR driver, it
has to be enabled via the CONFIG_PROG_SDRAM_TLB define.
Signed-off-by: Stefan Roese <sr@denx.de>
The config value for:
* CFG_ACR_PIPE_DEP
* CFG_ACR_RPTCNT
* CFG_SPCR_TSEC1EP
* CFG_SPCR_TSEC2EP
* CFG_SCCR_TSEC1CM
* CFG_SCCR_TSEC2CM
Were not being used when setting the appropriate register
Added:
* CFG_SCCR_USBMPHCM
* CFG_SCCR_USBDRCM
* CFG_SCCR_PCICM
* CFG_SCCR_ENCCM
To allow full config of the SCCR.
Also removed random CFG_SCCR settings in MPC8349EMDS, TQM834x, and sbc8349
that were just bogus.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Some device trees have a mac-address property, some have local-mac-address,
and some have both. To support all of these device trees, this patch
updates ftp_cpu_setup() to write the MAC address to mac-address if it exists.
This function already updates local-mac-address.
Signed-off-by: Timur Tabi <timur@freescale.com>
The code supply fixed and SPD initialization for MPC83xx DDR2 Controller.
it pass DDR/DDR2 compliance tests.
Signed-off-by: Xie Xiaobo <X.Xie@freescale.com>
MPC8360E rev2.0 have new spridr,and PVR value,
The MDS board for MPC8360E rev2.0 has 32M bytes Flash and 256M DDR2 DIMM.
Signed-off-by: Xie Xiaobo <X.Xie@freescale.com>
MPC8349E rev3.1 have new spridr,and PVR value,
The MDS board for MPC8349E rev3.1 has 32M bytes Flash and 256M DDR2 DIMM.
Signed-off-by: Xie Xiaobo<X.Xie@freescale.com>
The code that is ifdef'd with CONFIG_MPC8349 is actually applicable to all
MPC834X class processors. Change the protections from CONFIG_MPC8349 to
CONFIG_MPC834X so they are more generic.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
I've redone the SBC8349 support to match git-current, which
incorporates all the MPC834x updates from Freescale since the 1.1.6
release, including the DDR changes.
I've kept all the SBC8349 files as parallel as possible to the
MPC8349EMDS ones for ease of maintenance and to allow for easy
inspection of what was changed to support this board. Hence the SBC8349
U-Boot has FDT support and everything else that the MPC8349EMDS has.
Fortunately the Freescale updates added support for boards using CS0,
but I had to change spd_sdram.c to allow for board specific settings for
the sdram_clk_cntl (it is/was hard coded to zero, and that remains the
default if the board doesn't specify a value.)
Hopefully this should be mergeable as-is and require no whitespace
cleanups or similar, but if something doesn't measure up then let me
know and I'll fix it.
Thanks,
Paul.
Put the version (and magic) after the HRCW. This puts it in a fixed
location in flash, not at the start of flash but as close as we can get.
Signed-off-by: Jerry Van Baren <vanbaren@cideas.com>
For better format and style, I streamlined the 83xx head files,
including immap_83xx.h and mpc83xx.h. In the old head files, 1)
duplicated macro definition appear in the both files; 2) the structure
of QE immr is duplicated in the immap_83xx.h and immap_qe.h; 3) The
macro definition put inside the each structure. So, I cleaned up the
structure of QE immr from immap_83xx.h, deleted the duplicated stuff and
moved the macro definition to mpc83xx.h, Just like MPC8260.
CHANGELOG
*streamline the 83xx immr head file
Signed-off-by: Dave Liu <daveliu@freescale.com>
This patch updates the recently added Katmai board support. The biggest
change is the support of ECC DIMM modules in the 440SP(e) SPD DDR2
driver.
Please note, that still some problems are left with some memory
configurations. See the driver for more details.
Signed-off-by: Stefan Roese <sr@denx.de>
This patch adds support for the DDR2 controller used on the
440SP and 440SPe. It is tested on the Katmai (440SPe) eval
board and works fine with the following DIMM modules:
- Corsair CM2X512-5400C4 (512MByte per DIMM)
- Kingston ValueRAM KVR667D2N5/512 (512MByte per DIMM)
- Kingston ValueRAM KVR667D2N5K2/2G (1GByte per DIMM)
This patch also adds the nice functionality to dynamically
create the TLB entries for the SDRAM (tlb.c). So we should
never run into such problems with wrong (too short) TLB
initialization again on these platforms.
Signed-off-by: Stefan Roese <sr@denx.de>
Since the existing 4xx SPD SDRAM initialization routines for the
405 SDRAM controller and the 440 DDR controller don't have much in
common this patch splits both drivers into different files.
This is in preparation for the 440 DDR2 controller support (440SP/e).
Signed-off-by: Stefan Roese <sr@denx.de>
This patch adds support for multiple I2C busses on the PPC4xx
platforms. Define CONFIG_I2C_MULTI_BUS in the board config file
to make use of this feature.
It also merges the 405 and 440 i2c header files into one common
file 4xx_i2c.h.
Also the 4xx i2c reset procedure is reworked since I experienced
some problems with the first access on the 440SPe Katmai board.
Signed-off-by: Stefan Roese <sr@denx.de>
Block device read/write is anonymous data; there is no need to use a
typed pointer. void * is fine. Also add a hook for block_read functions
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Each of the filesystem drivers duplicate the get_dev routine. This change
merges them into a single function in part.c
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Previously the strapping DCR/SDR was read to determine if the internal PCI
arbiter is enabled or not. This strapping bit can be overridden, so now
the current status is read from the correct DCR/SDR register.
Signed-off-by: Stefan Roese <sr@denx.de>
Conflicts:
drivers/cfi_flash.c
The patch by Heiko Schocher <hs@pollux.denx.de> on Jan, 19, 2007
fixes cfi_driver bug for mpc7448hpc2 board. The default cfi_driver can support
mpc7448hpc2 board.
This patch fixes a problem with an incorrect setup for the refresh
timer of the 44x DDR controller in the file cpu/ppc4xx/sdram.c
Signed-off-by: Stefan Roese <sr@denx.de>
This code will optimize the DDR2 controller setup on a board specific
basis.
Note: This code doesn't work right now on the NAND booting image for the
Sequoia board, since it doesn't fit into the 4kBytes for the SPL image.
Signed-off-by: Stefan Roese <sr@denx.de>
multiplier table can not refect the real PLL clock behavior of these
processors. Please refer to the hardware specification for detailed
information of the corresponding processors.
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
The original search_one_table() function code can only processes the search
for the exception occurring in FLASH/ROM, because the exception and fixup
table usually locate in FLASH. If the exception address is also in
FLASH, it will be OK.
If the exception occurs in RAM, after the u-boot relocation, a
relocation offset should be added.
clean up the code in cpu/74xx_7xx/cpu.c
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
The conflicts due to a new mpc7448 p3m7448 board is in the main tree.
Merge branch 'master' into hpc2
Conflicts:
MAKEALL
cpu/74xx_7xx/cpu.c
cpu/74xx_7xx/cpu_init.c
cpu/74xx_7xx/speed.c
(1) remove some C++ comments.
(2) remove trailing white space.
(3) remove trailing empty line.
(4) Indentation by table.
(5) remove {} in one line condition.
(6) add space before '(' in function call.
Remove some weird printf () output.
Add necessary comments.
Modified Makefile to support building in a separate directory.
The soc node of the mpc52xx needs to be loaded with the IPB bus frequency,
not the XLB frequency.
This patch depends on the previous patches for MPC52xx device tree support
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
This patch adds support for the Prodrive P3M750 (PPC750 & MV64460)
and the P3M7448 (MPC7448 & MV64460) PMC modules. Both modules are
quite similar and share the same board directory "prodrive/p3mx"
and the same config file "p3mx.h".
Signed-off-by: Stefan Roese <sr@denx.de>
This patch adds the code and configuration necessary to boot with an
arch/powerpc Linux kernel.
Signed-off-by: Grant Likely <grant.likely@gmail.com>
Acked-by: Jon Loeliger <jdl@freescale.com>
Patch below corrects the setting of the zmiifer register, it was
overwritting the register rather than ORing the settings.
Signed-off-by: Neil Wilson <NWilson@airspan.com>
Signed-off-by: Stefan Roese <sr@denx.de>
and adapted board configs TQM5200 and yosemite accordingly. This commit
also makes the maximum number of root hub ports configurable
(CFG_USB_OHCI_MAX_ROOT_PORTS).
Fixed cpu/ppc4xx/start.S for 440EPx Errata: further corrects PPC440EPx
errata 1.12: 440_33 by moving patch up in code.
Signed-off-by: Jeff Mann <mannj@embeddedplanet.com>
Signed-off-by: Stefan Roese <sr@denx.de>
Update the 83xx tree to use I2C support in drivers/fsl_i2c.c. Delete
cpu/mpc83xx/i2c.c, include/asm-ppc/i2c.h, and all references to those files.
Added multiple I2C bus support to fsl_i2c.c.
Signed-off-by: Timur Tabi <timur@freescale.com>
Replace all instances of CFG_IMMRBAR with CFG_IMMR, so that the 83xx
tree matches the other 8xxx trees.
Signed-off-by: Timur Tabi <timur@freescale.com>
The 834x rev1.x silicon has one CPU5 errata.
The issue is when the data cache locked with
HID0[DLOCK], the dcbz instruction looks like no-op inst.
The right behavior of the data cache is when the data cache
Locked with HID0[DLOCK], the dcbz instruction allocates
new tags in cache.
The 834x rev3.0 and later and 8360 have not this bug inside.
So, when 834x rev3.0/8360 are working with ECC, the dcbz
instruction will corrupt the stack in cache, the processor will
checkstop reset.
However, the 834x rev1.x can work with ECC with these code,
because the sillicon has this cache bug. The dcbz will not
corrupt the stack in cache.
Really, it is the fault code running on fault sillicon.
This patch fix the incorrect dcbz operation. Instead of
CPU FP writing to initialise the ECC.
CHANGELOG:
* Fix the incorrect dcbz operation instead of CPU FP
writing to initialise the ECC memory. Otherwise, it
will corrupt the stack in cache, The processor will checkstop
reset.
Signed-off-by: Dave Liu <daveliu@freescale.com>
PREREQUISITE PATCHES:
* This patch can only be applied after the following patches have been applied:
1) DNX#2006090742000024 "Add support for multiple I2C buses"
2) DNX#2006090742000033 "Multi-bus I2C implementation of MPC834x"
3) DNX#2006091242000041 "Additional MPC8349 support for multibus i2c"
4) DNX#2006091242000078 "Add support for variable flash memory sizes on 83xx systems"
5) DNX#2006091242000069 "Add support for Errata DDR6 on MPC 834x systems"
CHANGELOG:
* Add support for the Freescale MPC8349E-mITX reference design platform.
The second TSEC (Vitesse 7385 switch) is not supported at this time.
Signed-off-by: Timur Tabi <timur@freescale.com>
Hello,
Attached is a patch implementing multiple I2C buses on the MPC834x CPU
family and the MPC8349EMDS board in particular.
This patch requires Patch 1 (Add support for multiple I2C buses).
Testing was performed on a 533MHz board.
/*** Note: This patch replaces ticket DNX#2006083042000027 ***/
Signed-off-by: Ben Warren <bwarren@qstreams.com>
CHANGELOG:
Implemented driver-level code to support two I2C buses on the
MPC834x CPU family and the MPC8349EMDS board. Available I2C bus speeds
are 50kHz, 100kHz and 400kHz on each bus.
regards,
Ben
CHANGELOG:
* Errata DDR6, which affects all current MPC 834x processors, lists changes
required to maintain compatibility with various types of DDR memory. This
patch implements those changes.
Signed-off-by: Timur Tabi <timur@freescale.com>
CHANGELOG:
* On 83xx systems, use the CFG_FLASH_SIZE macro to program the LBC local access
window registers, instead of using a hard-coded value of 8MB.
Signed-off-by: Timur Tabi <timur@freescale.com>
Incorporated the common unified variable names and the changes in preparation
for releasing mpc8360 patches.
Signed-off-by: Dave Liu <daveliu@freescale.com>
1. Add 7447A and 7448 processor support.
2. Add the following flags.
CFG_CONFIG_BUS_CLK : If the 74xx bus frequency can be configured dynamically
(such as by switch on board), this flag should be set.
CFG_EXCEPTION_AFTER_RELOCATE: If an exception occurs after the u-boot
relocates to RAM, this flag should be set.
CFG_SERIAL_HANG_IN_EXCEPTION: If the print out function will cause the
system hang in exception, this flag should be set.
There is a design issue for tsi108/109 pci configure read. When pci scan
the slots, if there is no pci card, the tsi108/9 will cause a machine
check exception for mpc7448 processor.
Signed-off-by: Alexandre Bounine <alexandreb@tundra.com>
Signed-off-by: Roy Zang <tie-fei.zang@freescale.com>
Patch by Haavard Skinnemoen, 06 Sep 2006
This patch adds support for the AT32AP CPU family and the AT32AP7000
chip, which is the first chip implementing the AVR32 architecture.
The AT32AP CPU core is a high-performance implementation featuring a
7-stage pipeline, separate instruction- and data caches, and a MMU.
For more information, please see the "AVR32 AP Technical Reference":
http://www.atmel.com/dyn/resources/prod_documents/doc32001.pdf
In addition to this, the AT32AP7000 chip comes with a large set of
integrated peripherals, many of which are shared with the AT91 series
of ARM-based microcontrollers from Atmel. Full data sheet is
available here:
http://www.atmel.com/dyn/resources/prod_documents/doc32003.pdf
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Introduced COFIG_FSL_I2C to select the common FSL I2C driver.
And removed hard i2c path from a few u-boot.lds scipts too.
Minor whitespace cleanups along the way.
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Both 8641 and 8641D have SVR == 0x8090, and are distinguished
by the byte in bits 16-23 instead.
Thanks to Jason Jin for noticing.
Signed-off-by: Jon Loeliger <jdl@freescale.com>
- Add support for PPC440EPx & PPC440GRx
- Add support for PPC440EP(x)/GR(x) NAND controller
in cpu/ppc4xx directory
- Add NAND boot functionality for Sequoia board,
please see doc/README.nand-boot-ppc440 for details
- This Sequoia NAND image doesn't support environment
in NAND for now. This will be added in a short while.
Patch by Stefan Roese, 07 Sep 2006
Modifications are based on the linux kernel approach and
support two use cases:
1) Add O= to the make command line
'make O=/tmp/build all'
2) Set environement variable BUILD_DIR to point to the desired location
'export BUILD_DIR=/tmp/build'
'make'
The second approach can also be used with a MAKEALL script
'export BUILD_DIR=/tmp/build'
'./MAKEALL'
Command line 'O=' setting overrides BUILD_DIR environent variable.
When none of the above methods is used the local build is performed and
the object files are placed in the source directory.
