Simon Glass [Mon, 9 Dec 2019 00:40:09 +0000 (17:40 -0700)]
x86: apl: Add LPC driver
This driver the LPC and provides a few functions to set up LPC features.
These should probably use ioctls() or perhaps, better, have specific
uclass methods.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Mon, 9 Dec 2019 00:40:08 +0000 (17:40 -0700)]
x86: apl: Add ITSS driver
This driver models some sort of interrupt thingy but there are so many
abreviations that I cannot find out what it stands for. Possibly something
to do with interrupts.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:58 +0000 (21:42 -0700)]
x86: apl: Add UART driver
Add a driver for the Apollo Lake UART. It uses the standard ns16550 device
but also sets up the input clock with LPSS and supports configuration via
of-platdata.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:54 +0000 (21:42 -0700)]
x86: Add a generic Intel GPIO driver
Add a GPIO driver which uses the pinctrl driver to access the pad
information. This driver relies on the GPIO nodes being subnodes to the
pinctrl device.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:53 +0000 (21:42 -0700)]
x86: Add a generic Intel pinctrl driver
Recent Intel SoCs share a pinctrl mechanism with many common elements. Add
an implementation of this core functionality, allowing SoC-specific
drivers to avoid adding common code.
As well as a pinctrl driver this provides a GPIO driver based on the same
code.
Once other SoCs use this driver we may consider moving more properties to
the device tree (e.g. the community info and pad definitions).
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:50 +0000 (21:42 -0700)]
mtd: spi: Export spi_flash_std_probe()
With of-platdata we need to create drivers for particular chips, or at
least drivers that are separate from the standard code, since C structures
are created by dtoc which are private to that driver.
To avoid duplicating the probing code, export this probe function for use
by these drivers.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:48 +0000 (21:42 -0700)]
spi: ich: Add TPL support
In TPL we want to reduce code size and support running with CONFIG_PCI
disabled. Add special code to handle this using a fixed BAR programmed
into the SPI on boot. Also cache the SPI flash to speed up boot.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:42 +0000 (21:42 -0700)]
spi: ich: Add mmio_base to struct ich_spi_platdata
It is useful to store the mmio base in platdata. It reduces the amount of
casting needed. Update the code and move the struct to the C file at the
same time, as we will need to use with of-platdata.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:41 +0000 (21:42 -0700)]
spi: ich: Various small tidy-ups
Use debug() instead of printf() to reduce code size and change a bool
return value to the use the 'bool' type. Also drop the global data
declaration since it not actually used. Finally, set the log category.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:38 +0000 (21:42 -0700)]
spi: ich: Move the protection/lockdown code into a function
Reduce the size of the probe function but putting this code into its own
function.
Also remove the assumption that the PCH is always a parent of the SPI
controller, as this is not the case APL platforms. Use driver model to
find the PCH instead.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:37 +0000 (21:42 -0700)]
spi: ich: Move init function just above probe()
It is annoying to have some of the init code in a different part of the
file. Move ich_init_controller() to just above probe() to keep things
together.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:36 +0000 (21:42 -0700)]
x86: spi: Don't enable SPI_FLASH_BAR by default
We don't normally need this on x86 unless the size of SPI flash devices is
larger than 16MB. This can be enabled by particular SoCs as needed, since
it adds to code size.
Drop the default enabling of this option on x86.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:33 +0000 (21:42 -0700)]
x86: Separate out U-Boot and device tree in ROM image
At present binman does not support updating a device tree that is part of
U-Boot (i.e u-boot.bin). Separate the entries into two so that we can get
updated entry information. This makes binman_entry_find() work correctly.
Do the same for SPL tool.
In both cases, group the two parts into a section so that SPL symbols get
the correct total size.
It may be possible for binman to handle this automatically at some point,
by ignoring u-boot.bin and always creating it from u-boot-nodtb.bin and
u-boot.dtb
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:32 +0000 (21:42 -0700)]
x86: Don't repeat microcode in U-Boot if not needed
At present if SPL sets up the microcode then it is still included in
U-Boot as well. This is wasteful as microcode is large. Adjust the logic
in the image to prevent this.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:31 +0000 (21:42 -0700)]
x86: Add an fdtmap and image-header
Add these entries to the ROM so that we can list the contents of an image
with 'binman ls'. The image-header is not essential but does speed up
access.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:30 +0000 (21:42 -0700)]
x86: Add an option to control the position of SPL
For Apollo Lake SPL is run from CAR (cache-as-RAM) which is in a different
location from where SPL must be placed in ROM. In other words, although
SPL runs before SDRAM is set up, it is not execute-in-place (XIP).
Add a Kconfig option for the ROM position.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:26 +0000 (21:42 -0700)]
x86: Disable microcode section for FSP2
At present we don't support loading microcode with FSP2. The correct way
to do this is by adding it to the FIT. For now, disable including
microcode in the image.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:11 +0000 (21:42 -0700)]
x86: Set the DRAM banks to reflect real location
At present with fsp a single DRAM bank is added which extends to the
whole size of memory. However there is typically only 2GB of memory
available below the 4GB boundary, and this is what is used by U-Boot while
running in 32-bit mode.
Scan the tables to set the banks correct. The first bank is set to memory
below 4GB, and the rest of memory is put into subsequent banks.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:10 +0000 (21:42 -0700)]
x86: Move fsp_prepare_mrc_cache() to fsp1 directory
This function needs to be different for FSP2, so move the existing
function into the fsp1 directory. Since it is only called from one file,
drop it from the header file.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:05 +0000 (21:42 -0700)]
x86: Add a new global_data member for the cache record
At present we reuse the mrc_output char * to also point to the cache
record after it has been set up. This is confusing and doesn't save much
data space.
Add a new mrc_cache member instead.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:03 +0000 (21:42 -0700)]
x86: Adjust mrccache_get_region() to use livetree
Change the algorithm to first find the flash device then read the
properties using the livetree API. With this change the device is not
probed so this needs to be done in mrccache_save().
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
This should take account of the end of the new cache record since a record
cannot extend beyond the end of the flash region. This problem was not
seen before due to the alignment of the relatively small amount of MRC
data.
But with Apollo Lake the MRC data is about 45KB, even if most of it is
zeroes.
Fix this bug and update the parameter name to be less confusing.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:42:01 +0000 (21:42 -0700)]
x86: Reduce mrccache record alignment size
At present the records are 4KB in size. This is unnecessarily large when
the SPI-flash erase size is 256 bytes. Reduce it so it will be more
efficient with Apollo Lake's 24-byte variable-data record.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:55 +0000 (21:41 -0700)]
pci: Add support for p2sb uclass
The Primary-to-Sideband bus (P2SB) is used to access various peripherals
through memory-mapped I/O in a large chunk of PCI space. The space is
segmented into different channels and peripherals are accessed by
device-specific means within those channels. Devices should be added in
the device tree as subnodes of the p2sb.
This adds a uclass and enables it for sandbox.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:53 +0000 (21:41 -0700)]
x86: power: Add an ACPI PMC uclass
Intel x86 SoCs have a power manager/controller which handles several
power-related aspects of the platform. Add a uclass for this, with a few
useful operations.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:51 +0000 (21:41 -0700)]
x86: Drop unnecessary cpu code for TPL
We don't need to know every detail about the CPU in TPL. Drop some
superfluous functions to reduce code size. Add a simple CPU detection
algorithm which just supports Intel and AMD, since we only support TPL
on Intel, so far.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:50 +0000 (21:41 -0700)]
x86: timer: Reduce timer code size in TPL on Intel CPUs
Most of the timer-calibration methods are not needed on recent Intel CPUs
and just increase code size. Add an option to use the known-good way to
get the clock frequency in TPL. Size reduction is about 700 bytes.
Note that version 1 of this commit caused bootstage to crash since the CPU
was not identified. This is corrected by changes previously applied to
make sure that the CPU is identified before spl_init() is called, such as
39146a2e0b x86: Move CPU init to before spl_init()
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:49 +0000 (21:41 -0700)]
x86: timer: use a timer base of 0
On x86 platforms the timer is reset to 0 when the SoC is reset. Having
this as the timer base is useful since it provides an indication of how
long it takes before U-Boot is running.
When U-Boot sets the timer base to something else, time is lost and we
no-longer have an accurate account of the time since reset. This
particularly affects bootstage.
Change the default to not read the timer base, leaving it at 0. Add an
option for when U-Boot is the secondary bootloader.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:46 +0000 (21:41 -0700)]
board_r: Move early-timer init later
At present the early timer init happens as soon as driver model is set up.
This makes it impossible to do anything that needs driver model but must
run before devices are probed (as needed with Intel's FSP-S, for example).
In any case it is not a good idea to tie probing of particular drivers too
closely to the DM init.
Create a new function to init the timer and put it a bit later in the
sequence.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:44 +0000 (21:41 -0700)]
fdt: Show the preprocessed .dts file on error
When device-tree compilation fails it is sometimes tricky to see which
line is broken, since the input file to dtc is a pre-processed version
of the device tree.
Add a line that points to the file that needs to be checked:
When the error is in the main .dts file, output is something like this:
output: 'Error: arch/x86/dts/.chromebook_coral.dtb.pre.tmp:478.46-47
syntax error
FATAL ERROR: Unable to parse input tree
but in fact looking at that file shows nothing useful:
This shows that the filename (normally "fitimage.bin") has not been
inserted the preprocess, leading to the realisation that the value should
be CONFIG_IFWI_INPUT_FILE.
If the above does not make sense, I encourage people to try introducing
errors in the device tree preprocessed values.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:43 +0000 (21:41 -0700)]
x86: spi: Add helper functions for Intel Fast SPI
Most x86 CPUs use a mechanism where the SPI flash is mapped into the very
top of 32-bit address space, so that it can be executed in place and read
simply by copying from memory. For an 8MB ROM the mapping starts at
0xff800000.
However some recent Intel CPUs do not use a simple 1:1 memory map. Instead
the map starts at a different address and not all of the SPI flash is
accessible through the map. This 'Fast SPI' feature requires that U-Boot
check the location of the map. It is also possible (optionally) to read
from the SPI flash using a driver.
Add support for booting from Fast SPI. The memory-mapped version is used
by both TPL and SPL on Apollo Lake.
In respect of a SPI flash driver, the actual SPI driver is ich.c - this
just adds a few helper functions and definitions.
This is used by Apollo Lake.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:42 +0000 (21:41 -0700)]
i2c: designware: Support use in SPL
Allow this driver to set up an IO address in SPL using an 'early-regs'
property. This allows SPL to use the I2C driver without having to enable
the full PCI stack.
Also split out ofdata_to_platdata in designware driver since this is more
correct, and more convenient for the new logic.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:40 +0000 (21:41 -0700)]
i2c: designware: Tidy up PCI support
This is hacked into the driver at present. It seems better to have it as
a separate driver that uses the base driver. Create a new file and put
the X86 code into it.
Actually the Baytrail settings should really come from the device tree.
Note that 'has_max_speed' is added as well. This is currently always false
but since only Baytrail provides the config, it does not affect operation
for other devices.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Heiko Schocher <hs@denx.de> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:39 +0000 (21:41 -0700)]
net: Move the checksum functions to lib/
These functions are used by code outside the network support, so move them
to lib/ to be more accessible.
Without this, the functions are only accessible in SPL/TPL only if
CONFIG_SPL/TPL_NET are defined. Many boards do not enable those option but
still want to do checksums in this format.
Fix up a few code-style nits while we are here.
Signed-off-by: Simon Glass <sjg@chromium.org> Acked-by: Joe Hershberger <joe.hershberger@ni.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:38 +0000 (21:41 -0700)]
dm: pci: Move pci_get_devfn() into a common file
Early in boot it is necessary to decode the PCI device/function values for
particular peripherals in the device tree or of-platdata. This is needed
in TPL where CONFIG_PCI is not defined.
To handle this, move pci_get_devfn() into a file that is built even when
CONFIG_PCI is not defined.
Also add a function for use by of-platdata, to convert a reg property to
a pci_dev_t.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:37 +0000 (21:41 -0700)]
dm: pci: Allow delaying auto-config until after relocation
At present PCI auto-configuration happens in U-Boot both before and after
relocation. This is a waste of time and may mess up static addresses used
in board_init_f(). Adjust the code to supporting doing auto-configuration
once, after relocation, under control of a device-tree property.
This is needed for Apollo Lake for debugging the silicon-init code. Once
the UART is moved to a different MMIO address the debug UART does not work
and any debug output in Apollo Lake's arch_fsp_init_r() causes a hang.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:36 +0000 (21:41 -0700)]
dm: core: Fix offset_to_ofnode() with invalid offset
If the offset is -1 this function correctly sets up a null ofnode. But if
the offset is any other negative number (e.g. -FDT_ERR_BADPATH) then it
does the wrong thing.
An offset of -1 in ofnode indicates that the ofnode is not valid. Any
other negative value is not handled by ofnode_valid(). We could of course
change that function, but it seems much better to always use the same
value for an invalid node.
Fix it by setting the offset to -1 if it is invalid for any reason.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:35 +0000 (21:41 -0700)]
dm: gpio: Allow control of GPIO uclass in SPL
At present if CONFIG_SPL_GPIO_SUPPORT is enabled then the GPIO uclass
is included in SPL/TPL without any control for boards. Some boards may
want to disable this to reduce code size where GPIOs are not needed in
SPL or TPL.
Add a new Kconfig option to permit this. Default it to 'y' so that
existing boards work correctly.
Change existing uses of CONFIG_DM_GPIO to CONFIG_IS_ENABLED(DM_GPIO) to
preserve the current behaviour. Also update the 74x164 GPIO driver since
it cannot build with SPL.
This allows us to remove the hacks in config_uncmd_spl.h and
Makefile.uncmd_spl (eventually those files should be removed).
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Simon Glass [Sat, 7 Dec 2019 04:41:34 +0000 (21:41 -0700)]
binman: Add a library to access binman entries
SPL and TPL can access information about binman entries using link-time
symbols but this is not available in U-Boot proper. Of course it could be
made available, but the intention is to just read the device tree.
Add support for this, so that U-Boot can locate entries.
Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tom Rini [Wed, 11 Dec 2019 13:17:19 +0000 (08:17 -0500)]
Merge tag 'fix-for-2020.01' of https://gitlab.denx.de/u-boot/custodians/u-boot-i2c
i2c bugfixes for 2020.01
- i2c: i2c_cdns: fix write timeout on fifo boundary
fixes timout issue when writting number of bytes is multiple
of the FIFO depth.
Tom Rini [Wed, 11 Dec 2019 13:16:16 +0000 (08:16 -0500)]
Merge tag 'u-boot-atmel-fixes-2020.01-a' of https://gitlab.denx.de/u-boot/custodians/u-boot-atmel
- First set of u-boot-atmel fixes for 2020.01 cycle:
This set includes a small fix for gpio bank names, one for removing
unused headers (also touches some other boards), and a fix for the QSPI
env read on one of the boards.
The rpi_4_32b_defconfig states that only one DRAM bank is present. This
leads to a wrong configuration of the available DRAM. Fix this by
setting the DRAM bank config accordingly.
Up to now we only update the DRAM banks when we are define
CONFIG_BCM2711. But our one binary approach uses a config that supports
BCM2837 and BCM2711. As a result we only see one gibibyte of RAM on
Raspberry Pi 4, even if it has more RAM.
Fix this by calling dram_init_banksize.
Fixes: 5694090670 ("ARM: defconfig: add unified config for RPi3 and RPi4") Signed-off-by: Matthias Brugger <mbrugger@suse.com>
To update the dram bank information from device-tree we use
fdtdec_decode_ram_size() which expectes the the size-cells and
address-cells to be defined in the memory node. For normal system RAM
these values are defined in the root node. When the values differ from
the default values defined in the spec, we can end up with wrong RAM
bank information.
Switch to the "standard" way to update the RAM bank information to
avoid this.
Fixes: 9de5b89e4c ("rpi4: enable dram bank initialization") Signed-off-by: Matthias Brugger <mbrugger@suse.com>
Michael Auchter [Mon, 9 Dec 2019 18:16:16 +0000 (18:16 +0000)]
i2c: i2c_cdns: fix write timeout on fifo boundary
This fixes an issue that would cause I2C writes to timeout when the
number of bytes is a multiple of the FIFO depth (i.e. 16 bytes).
Within the transfer loop, after writing the data register with a new
byte to transfer, if the transfer size equals the FIFO depth, the loop
pauses until the INTERRUPT_COMP bit asserts to indicate data has been
sent. This same check is performed after the loop as well to ensure data
has been transferred prior to returning.
In the case where the amount of data to be written is a multiple of the
FIFO depth, the transfer loop would wait for the INTERRUPT_COMP bit to
assert after writing the final byte, and then wait for this bit to
assert once more. However, since the transfer has finished at this
point, no new data has been written to the data register, and hence
INTERRUPT_COMP will never assert.
Fix this by only waiting for INTERRUPT_COMP in the transfer loop if
there's still data to be written.
Signed-off-by: Michael Auchter <michael.auchter@ni.com> Reviewed-by: Simon Glass <sjg@chromium.org>
Tom Rini [Fri, 6 Dec 2019 20:31:31 +0000 (15:31 -0500)]
buildman: Ignore blank lines during size checks
Today when parsing the .sizes files we get a warning about an invalid
line in the file as it's blank. Solve this by checking that we have a
non-blank line prior to processing.
Cc: Simon Glass <sjg@chromium.org> Signed-off-by: Tom Rini <trini@konsulko.com> Reviewed-by: Simon Glass <sjg@chromium.org>
Simon Glass [Thu, 5 Dec 2019 22:59:14 +0000 (15:59 -0700)]
buildman: Add options to get the arch and toolchain info
Sometimes it is useful for external tools to use buildman to provide the
toolchain information. Add an -a option which shows the value to use for
the ARCH environment variable, and -A which does the same for
CROSS_COMPILE