Commit graph

130 commits

Author SHA1 Message Date
Bin Meng
3c8ae536ec x86: Define macros for pci configuration space access
Move PCI_REG_ADDR and PCI_REG_DATA from arch/x86/lib/pci_type1.c to
arch/x86/include/asm/pci.h, also define PCI_CFG_EN so that these
macros can be used for pci configuration space access.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-02-06 12:07:40 -07:00
Simon Glass
447f8b018e x86: Allow a UART to be set up before the FSP is ready
Since the FSP is a black box it helps to have some sort of debugging
available to check its inputs. If the debug UART is in use, set it up
after CAR is available.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2015-02-06 12:07:38 -07:00
Simon Glass
f0809f9a38 x86: Remove unnecessary casts and fix comment typos
Tidy up the FSP support code a little.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2015-02-06 12:07:37 -07:00
Simon Glass
91785f70b9 x86: mmc: Move common FSP functions into a common file
Since these board functions seem to be the same for all boards which use
FSP, move them into a common file. We can adjust this later if future FSPs
need more flexibility.

This creates a generic PCI MMC device.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
2015-02-06 12:07:36 -07:00
Simon Glass
7b02bf3c7d x86: Make CAR and DRAM FSP code common
For now this code seems to be the same for all FSP platforms. Make it
common until we see what differences are required.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
2015-02-05 22:16:44 -07:00
Simon Glass
82196cf34f x86: Adjust the FSP types slightly
To avoid casts, find_fsp_header() should return a pointer. Add asmlinkage
to two API functions which use that convention. UPD_TERMINATOR is common
so move it into a common file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
2015-02-05 22:16:43 -07:00
Simon Glass
1021af4ded x86: Move common FSP code into a common location
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
2015-02-05 22:16:43 -07:00
Bin Meng
3b621ccabd x86: Test mtrr support flag before accessing mtrr msr
On some x86 processors (like Intel Quark) the MTRR registers are not
supported. This is reflected by the CPUID (EAX 01H) result EDX[12].
Accessing the MTRR registers on such processors will cause #GP so we
must test the support flag before accessing MTRR MSRs.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-01-23 17:24:55 -07:00
Sebastien Ronsse
07570e7097 x86: Fix out of bounds irq handlers access
Using coreboot-x86_defconfig, the following error occurred prior to this modification:
CC	arch/x86/lib/interrupts
arch/x86/lib/interrupts.c: In function ‘do_irqinfo’:
arch/x86/lib/interrupts.c:134:24: error: iteration 16u invokes undefined behavior [-Werror=aggressive-loop-optimizations]
   if (irq_handlers[irq].handler != NULL) {
                        ^
arch/x86/lib/interrupts.c:133:2: note: containing loop
  for (irq = 0; irq <= CONFIG_SYS_NUM_IRQS; irq++) {
  ^
cc1: all warnings being treated as errors
scripts/Makefile.build:275: recipe for target 'arch/x86/lib/interrupts.o' failed
make[1]: *** [arch/x86/lib/interrupts.o] Error 1
Makefile:1093: recipe for target 'arch/x86/lib' failed
make: *** [arch/x86/lib] Error 2

Change-Id: I3572a822081b72ab760f1eb99442e1161d3d167e
Signed-off-by: Sebastien Ronsse <sronsse@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-01-23 17:24:54 -07:00
Bin Meng
3ba6a0f4f6 x86: Allow a hardcoded TSC frequency provided by Kconfig
By default U-Boot automatically calibrates TSC running frequency via
MSR and PIT. The calibration may not work on every x86 processor, so
a new Kconfig option CONFIG_TSC_CALIBRATION_BYPASS is introduced to
allow bypassing the calibration and assign a hardcoded TSC frequency
CONFIG_TSC_FREQ_IN_MHZ.

Normally the bypass should be turned on in a simulation environment
like qemu.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-01-13 07:25:02 -08:00
Bin Meng
b2439aecd3 x86: fsp: Drop get_hob_type() and get_hob_length()
These two are not worth having separate inline functions as they are
really simple, so drop them.

Also changed 'type' parameter of fsp_get_next_hob() from u16 to uint.

Suggested-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-01-13 07:25:02 -08:00
Simon Glass
cb3b2e62ca x86: Add an 'mtrr' command to list and adjust MTRRs
It is useful to be able to see the MTRR setup in U-Boot. Add a command
to list the state of the variable MTRR registers and allow them to be
changed.

Update the documentation to list some of the available commands.

This does not support fixed MTRRs as yet.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
2015-01-13 07:25:02 -08:00
Simon Glass
db55bd7dad x86: Commit the current MTRRs before relocation
Once we stop running from ROM we should set up the MTTRs to speed up
execution. This is only needed for platforms that don't have an FSP.
Also in the Coreboot case, the MTRRs are set up for us.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-01-13 07:25:01 -08:00
Simon Glass
f4a6f0aed0 x86: Tidy up VESA mode numbers
There are some bits which should be ignored when displaying the mode number.
Make sure that they are not included in the mode that is displayed.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-01-13 07:24:59 -08:00
Simon Glass
818f602112 x86: Use cache, don't clear the display in video BIOS
There is no need to run with the cache disabled, and there is no point in
clearing the display frame buffer since U-Boot does it later.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-01-13 07:24:59 -08:00
Bin Meng
949dbc12db x86: Simplify the fsp hob access functions
Remove the troublesome union hob_pointers so that some annoying casts
are no longer needed in those hob access routines. This also improves
the readability.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-01-12 17:03:41 -08:00
Bin Meng
255fd5caa5 x86: Clean up the FSP support codes
This is the follow-on patch to clean up the FSP support codes:

- Remove the _t suffix on the structures defines
- Use __packed for structure defines
- Use U-Boot's assert()
- Use standard bool true/false
- Remove read_unaligned64()
- Use memcmp() in the compare_guid()
- Remove the cast in the memset() call
- Replace some magic numbers with macros
- Use panic() when no valid FSP image header is found
- Change some FSP utility routines to use an fsp_ prefix
- Add comment blocks for asm_continuation and fsp_init_done
- Remove some casts in find_fsp_header()
- Change HOB access macros to static inline routines
- Add comments to mention find_fsp_header() may be called in a
  stackless environment
- Add comments to mention init(&params) in fsp_init() cannot
  be removed

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2014-12-18 17:26:08 -07:00
Masahiro Yamada
e6126a5872 x86: move arch-specific asmlinkage to <asm/linkage.h>
Commit 65dd74a674 (x86: ivybridge: Implement SDRAM init) introduced
x86-specific asmlinkage into arch/x86/include/asm/config.h.

Commit ed0a2fbf14 (x86: Add a definition of asmlinkage) added the
same macro define again, this time, into include/common.h.
(Please do not add arch-specific stuff to include/common.h any more;
it is already too cluttered.)

The generic asmlinkage is defined in <linux/linkage.h>.  If you want
to override it with an arch-specific one, the best way is to add it
to <asm/linkage.h> like Linux Kernel.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
2014-12-15 07:22:53 -07:00
Bin Meng
ba7b38a529 x86: Add a simple command to show FSP HOB information
FSP builds a series of data structures called the Hand-Off-Blocks
(HOBs) as it progresses through initializing the silicon. These data
structures conform to the HOB format as described in the Platform
Initialization (PI) specification Volume 3 Shared Architectual
Elements specification, which is part of the UEFI specification.

Create a simple command to parse the HOB list to display the HOB
address, type and length in bytes.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2014-12-13 22:32:06 -07:00
Bin Meng
bceb9f0fc8 x86: Support Intel FSP initialization path in start.S
Per Intel FSP architecture specification, FSP provides 3 routines
for bootloader to call. The first one is the TempRamInit (aka
Cache-As-Ram initialization) and the second one is the FspInit
which does the memory bring up (like MRC for other x86 targets)
and chipset initialization. Those two routines have to be called
before U-Boot jumping to board_init_f in start.S.

The FspInit() will return several memory blocks called Hand Off
Blocks (HOBs) whose format is described in Platform Initialization
(PI) specification (part of the UEFI specication) to the bootloader.
Save this HOB address to the U-Boot global data for later use.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2014-12-13 22:32:05 -07:00
Bin Meng
fe0c33a5ac x86: Clean up asm-offsets
Move GD_BIST from lib/asm-offsets.c to arch/x86/lib/asm-offsets.c
as it is x86 arch specific stuff. Also remove GENERATED_GD_RELOC_OFF
which is not referenced anymore.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2014-12-13 22:32:04 -07:00
Masahiro Yamada
afc366f01b Replace <compiler.h> with <linux/compiler.h>
Including <linux/compiler.h> is enough for general use.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-12-08 09:35:46 -05:00
Simon Glass
0ca2426bea x86: Add support for running option ROMs natively
On x86 machines we can use an emulator to run option ROMS as with other
architectures. But with some additional effort (mostly due to the 16-bit
nature of option ROMs) we can run them natively. Add support for this.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-11-25 06:38:57 -07:00
Bin Meng
1dae2e0eb6 x86: Refactor interrupt_init()
Rename interrupt_init() in arch/x86/lib/pcat_interrupts.c to
i8259_init() and create a new interrupt_init() in
arch/x86/cpu/interrupt.c to call i8259_init() followed by a
call to cpu_init_interrupts().

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
2014-11-25 06:34:02 -07:00
Bin Meng
4372a9eca5 x86: Call cpu_init_interrupts() from interrupt_init()
Currently cpu_init_interrupts() is called from cpu_init_r() to
setup the interrupt and exception of the cpu core, but at that
time the i8259 has not been initialized to mask all the irqs
and remap the master i8259 interrupt vector base, so the whole
system is at risk of being interrupted, and if interrupted,
wrong interrupt/exception message is shown.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
2014-11-25 06:34:02 -07:00
Simon Glass
a0bd851ece x86: Set up edge triggering on interrupt 9
Add this additional init in case it is needed by the OS.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2014-11-25 06:34:00 -07:00
Simon Glass
512e581c86 x86: Panic if there is no relocation data
This normally indicates a problem which will prevent relocation from
functioning, resulting in a hang. Panic in this case to make it easier
to debug.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2014-11-25 06:33:59 -07:00
Simon Glass
65dd74a674 x86: ivybridge: Implement SDRAM init
Implement SDRAM init using the Memory Reference Code (mrc.bin) provided in
the board directory and the SDRAM SPD information in the device tree. This
also needs the Intel Management Engine (me.bin) to work. Binary blobs
everywhere: so far we have MRC, ME and microcode.

SDRAM init works by setting up various parameters and calling the MRC. This
in turn does some sort of magic to work out how much memory there is and
the timing parameters to use. It also sets up the DRAM controllers. When
the MRC returns, we use the information it provides to map out the
available memory in U-Boot.

U-Boot normally moves itself to the top of RAM. On x86 the RAM is not
generally contiguous, and anyway some RAM may be above 4GB which doesn't
work in 32-bit mode. So we relocate to the top of the largest block of
RAM we can find below 4GB. Memory above 4GB is accessible with special
functions (see physmem).

It would be possible to build U-Boot in 64-bit mode but this wouldn't
necessarily provide any more memory, since the largest block is often below
4GB. Anyway U-Boot doesn't need huge amounts of memory - even a very large
ramdisk seldom exceeds 100-200MB. U-Boot has support for booting 64-bit
kernels directly so this does not pose a limitation in that area. Also there
are probably parts of U-Boot that will not work correctly in 64-bit mode.
The MRC is one.

There is some work remaining in this area. Since memory init is very slow
(over 500ms) it is possible to save the parameters in SPI flash to speed it
up next time. Suspend/resume support is not fully implemented, or at least
it is not efficient.

With this patch, link boots to a prompt.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-11-21 07:34:15 +01:00
Simon Glass
5c1b685e46 x86: Allow timer calibration to work on ivybridge
Unfortunately MSR_FSB_FREQ is not available on this CPU, and the PIT method
seems to take up to 50ms which is much too long.

For this CPU we know the frequency, so add another special case for now.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2014-11-21 07:24:12 +01:00
Simon Glass
003504b6fe x86: Remove unnecessary find_fdt(), prepare_fdt() functions
These are no-longer needed so drop them.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2014-11-21 07:24:12 +01:00
Bin Meng
258b1357c6 x86: Save TSC frequency in the global data
Return the saved TSC frequency in get_tbclk_mhz().

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
2014-11-21 07:24:10 +01:00
Bin Meng
80de049561 x86: Add quick TSC calibration via PIT
Use the same way that Linux does for quick TSC calibration via PIT
when calibration via MSR fails.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2014-11-21 07:24:10 +01:00
Bin Meng
076bb44b0e x86: Do TSC MSR calibration only for known/supported CPUs
Using MSR_PLATFORM_INFO (0xCE) to calibrate TSR will cause #GP on
processors which do not have this MSR. Instead only doing the MSR
calibration for known/supported CPUs.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
2014-11-21 07:24:10 +01:00
Simon Glass
2c363cb003 x86: Correct a few progress message nits
We should use puts() instead of printf() where possible. Also clarify
the setup.bin message.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-10-28 20:44:27 -06:00
Simon Glass
61643ae61a x86: bootm: Support booting a 64-bit raw kernel
Detect an x86_64 kernel and boot it in 64-bit mode.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-10-28 20:44:12 -06:00
Simon Glass
76539383ea x86: Move kernel boot function to arch/x86/lib/bootm.c
The boot_zimage() function is badly named it can also boot a raw kernel.
Rename it, and try to avoid pointers for memory addresses as it involves
lots of casting.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-10-28 20:43:58 -06:00
Simon Glass
7bddac947d x86: Move paging functions into cpu.c
These functions really don't belong in physmem as they relate to the
cpu. Move them.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-10-28 20:42:51 -06:00
Simon Glass
6bcb8ade30 x86: Use correct printf() format string for uintptr_t
Use the inttypes header file to provide this.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-10-27 11:04:01 -04:00
Simon Glass
9c284ffd93 dm: x86: Remove ebp assembler warning in zimage.c
This code generates warnings with recent gcc versions. We really don't need
the clobber specification, so just drop it.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-10-23 19:45:28 -06:00
Masahiro Yamada
dd43fa22de x86: set CONFIG_USE_PRIVATE_LIBGCC to y
The motivation of this commit is to change CONFIG_USE_PRIVATE_LIBGCC
to a boolean macro so we can move it to Kconfig.

In the current implementation, there are two forms of syntax
for this macro:

  - CONFIG_USE_PRIVATE_LIBGCC=y
  - CONFIG_USE_PRIVATE_LIBGCC=path/to/private/libgcc

The latter is only used by x86 architecture.
With a little bit refactoring, it can be converted to the former.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
2014-10-23 13:19:04 -04:00
Simon Glass
97d1e0c850 x86: Allow cmdline setup in setup_zimage() to be optional
If we are passing this using the device tree then we may not want to
set this up here.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-10-22 09:03:05 -06:00
Simon Glass
0d0ba59ccd x86: Rewrite bootm.c to make it similar to ARM
The x86 bootm code is quite special, and geared to zimage. Adjust it
to support device tree and make it more like the ARM code, with
separate bootm stages and functions for each stage.

Create a function announce_and_cleanup() to handle printing the
"Starting kernel ..." message and put it in bootm so it is in one
place and can be used by any loading code. Also move the
board_final_cleanup() function into bootm.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-10-22 09:03:05 -06:00
Masahiro Yamada
c79cba37b3 cosmetic: replace MIN, MAX with min, max
The macro MIN, MAX is defined as the aliase of min, max,
respectively.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2014-09-24 18:30:29 -04:00
Simon Glass
709ea543b9 stdio: Pass device pointer to stdio methods
At present stdio device functions do not get any clue as to which stdio
device is being acted on. Some implementations go to great lengths to work
around this, such as defining a whole separate set of functions for each
possible device.

For driver model we need to associate a stdio_dev with a device. It doesn't
seem possible to continue with this work-around approach.

Instead, add a stdio_dev pointer to each of the stdio member functions.

Note: The serial drivers have the same problem, but it is not strictly
necessary to fix that to get driver model running. Also, if we convert
serial over to driver model the problem will go away.

Code size increases by 244 bytes for Thumb2 and 428 for PowerPC.

22: stdio: Pass device pointer to stdio methods
       arm: (for 2/2 boards)  all +244.0  bss -4.0  text +248.0
   powerpc: (for 1/1 boards)  all +428.0  text +428.0

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Marek Vasut <marex@denx.de>
Reviewed-by: Marek Vasut <marex@denx.de>
2014-07-23 14:07:23 +01:00
Simon Glass
91d0be1dd8 stdio: Remove redundant code around stdio_register() calls
There is no point in setting a structure's memory to NULL when it has
already been zeroed with memset().

Also, there is no need to create a stub function for stdio to call - if the
function is NULL it will not be called.

This is a clean-up, with no change in functionality.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Marek Vasut <marex@denx.de>
2014-07-23 14:07:23 +01:00
Masahiro Yamada
254d68b601 kbuild: move asm-offsets.c from SoC directory to arch/$(ARCH)/lib
U-Boot has supported two kinds of asm-offsets.h.

One is generic for all architectures and its source is located at
./lib/asm-offsets.c.

The other is SoC specific and its source is under SoC directory.
The problem here is that only boards with SoC directory can use
the asm-offsets infrastructure.
Putting asm-offsets.c right under CPU directory does not work.

Now a new demand is coming. PowerPC folks want to use asm-offsets.
But no PowerPC boards have SoC directory.

It seems inconsistent that some boards add asm-offsets.c to SoC
directoreis and some to CPU directories.
It looks more reasonable to put asm-offsets.c under arch/$(ARCH)/lib.

This commit merges asm-offsets.c under SoC directories into
arch/$(ARCH)/lib/asm-offsets.c.

By the way, I doubt the necessity of some entries in asm-offsets.c.
I am leaving refactoring to the board maintainers.
Please check "TODO" in the comment blocks in
arch/{arm,nds32}/lib/asm-offsets.c.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Yuantian Tang <Yuantian.Tang@freescale.com>
2014-03-28 15:06:29 -04:00
Masahiro Yamada
b6e53eb320 kbuild, x86: use a short log for arch/x86/lib/libgcc.a
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
2014-03-12 17:04:42 -04:00
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
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
Masahiro Yamada
3954b739b3 x86: convert makefiles to Kbuild style
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
2013-11-01 11:42:12 -04:00