If semihosting is disabled, then the user has no debugger attached, and
will not see any messages. Don't create a serial device in this
instance, to (hopefully) fall back on another working serial device.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
If a debugger is not attached to U-Boot, semihosting calls will raise a
synchronous abort exception. Try to catch this and disable semihosting
so we can e.g. use another uart if one is available. In the immediate
case, we return an error, since it is not always possible to check for
semihosting beforehand (debug uart, user-initiated load command, etc.)
We handle all possible semihosting instructions, which is probably
overkill. However, we do need to keep track of what instruction set
we're using so that we don't suppress an actual error.
A future enhancement could try to determine semihosting capability by
inspecting the processor state. There's an example of this at [1] for
RISC-V. The equivalent for ARM would inspect the monitor modei
enable/select bits of the DSCR. However, as the article notes, an
exception handler is still helpful in order to catch disconnected
debuggers.
[1] https://tomverbeure.github.io/2021/12/30/Semihosting-on-RISCV.html#avoiding-hangs-when-a-debugger-is-not-connected
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
These functions are intended to support detecting semihosting and
falling back gracefully to alternative implementations. The test starts
by making semihosting call. SYS_ERRNO is chosen because it should not
mutate any state. If this semihosting call results in an exception
(rather than being caught by the debugger), then the exception handler
should call disable_semihosting() and resume execution after the call.
Ideally, this would just be part of semihosting by default, and not a
separate config. However, to reduce space ARM SPL doesn't include
exception vectors by default. This means we can't detect if a
semihosting call failed unless we enable them. To avoid forcing them to
be enabled, we use a separate config option. It might also be possible
to try and detect whether a debugger has enabled (by reading HDE from
DSCR), but I wasn't able to figure out a way to do this from all ELs.
This patch just introduces the generic code to handle detection. The
next patch will implement it for arm64 (but not arm32).
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This imports some defines for esr and spsr from Linux v5.16. I have
modified the includes and fixed some indentation nits but otherwise it
is the same. There are a lot more defines than we need, but it doesn't
hurt.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This register holds "pstate" which includes (among other things) the
instruction mode the CPU was in when the exception was taken. This is
necessary to correctly interpret instructions at elr.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
To avoid passing around an extra register everywhere, save esr in
pt_regs like the rest. For proper alignment we need to have a second
(unused) register. All the printfs have to be adjusted, since
it's now an unsigned long and not an int.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This adds support for booting entirely from JTAG while using a
hard-coded RCW. With these steps, it is not necessary to program a
"good" RCW using CodeWarrior. The method here can be performed with any
JTAG adapter supported by OpenOCD, including the on-board CMSIS-DAP
(albeit very slowly).
These steps require LS1046A support in OpenOCD, which was added in [1].
[1] 5b70c1f679/
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
[trini: Add reference to doc/board/nxp/ls1046ardb.rst]
This documents how to use semihosting, the new semihosting features, and
how to migrate from smhload.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This adds a serial driver which uses semihosting calls to read and write
to the host's console. For convenience, if CONFIG_DM_SERIAL is enabled,
we will instantiate a serial driver. This allows users to enable this
driver (which has no physical device) without modifying their device
trees or board files. We also implement a non-DM driver for SPL, or for
much faster output in U-Boot proper.
There are three ways to print to the console:
Method Baud
================== =====
smh_putc in a loop 170
smh_puts 1600
smh_write with :tt 20000
================== =====
These speeds were measured using a 175 character message with a J-Link
adapter. For reference, U-Boot typically prints around 2700 characters
during boot on this board. There are two major factors affecting the
speed of these functions. First, each breakpoint incurs a delay. Second,
each debugger memory transaction incurs a delay. smh_putc has a
breakpoint and memory transaction for every character. smh_puts has one
breakpoint, but still has to use a transaction for every character. This
is because we don't know the length up front, so OpenOCD has to check if
each character is nul. smh_write has only one breakpoint and one memory
transfer.
DM serial drivers can only implement a putc interface, so we are stuck
with the slowest API. Non-DM drivers can implement puts, which is vastly
more efficient. When the driver starts up, we try to open :tt. Since
this is an extension, this may fail. If it does, we fall back to
smh_puts. We don't check :semihosting-features, since there are
nonconforming implementations (OpenOCD) which don't implement it (but
*do* implement :tt).
Some semihosting implementations (QEMU) don't handle READC properly. To
work around this, we try to use open/read (much like for stdin) if
possible.
There is no non-blocking I/O available, so we don't implement pending.
This will cause __serial_tstc to always return true. If
CONFIG_SERIAL_RX_BUFFER is enabled, _serial_tstc will try and read
characters forever. To avoid this, we depend on this config being
disabled.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
This adds three wrappers around the semihosting commands for reading and
writing to the host console. We use the more standard getc/putc/puts
names instead of readc/writec/write0 for familiarity.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This command's functionality is now completely implemented by the
standard fs load command. Convert the vexpress64 boot command (which is
the only user) and remove the implementation.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Most U-Boot command deal with start/size instead of start/end. Convert
the "fdt chosen" command to use these semantics as well. The only user
of this subcommand is vexpress, so convert the smhload command to use
this as well. We don't bother renaming the variable in vexpress64's
bootcommand, since it will be rewritten in the next commit.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This adds a filesystem which is backed by the host's filesystem. It is
modeled off of sandboxfs, which has very similar aims. Semihosting
doesn't support listing directories (except with SYS_SYSTEM), so neither
do we. it's possible to optimize a bit for the common case of reading a
whole file by omitting a call to smh_seek, but this is left as a future
optimization.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This adds a boot method for loading the next stage from the host. It is
mostly modeled off of spl_load_image_ext. I am not really sure why/how
spl_load_image_fat uses three different methods to load the image, but
the simple case seems to work OK for now.
To control the presence of this boot method, we add a config symbol.
While we're at it, we update the original semihosting config symbol.
I think semihosting has some advantages of other forms of JTAG boot.
Common other ways to boot from JTAG include:
- Implementing DDR initialization through JTAG (typically with dozens of
lines of TCL) and then loading U-Boot. The DDR initialization
typically uses hard-coded register writes, and is not easily adapted
to different boards. BOOT_DEVICE_SMH allows booting with SPL,
leveraging U-Boot's existing DDR initialization code. This is the
method used by NXP's CodeWarrior IDE on Layerscape processors (see
AN12270).
- Loading a bootloader into SDRAM, waiting for it to initialize DDR, and
then loading U-Boot. This is tricky, because the debugger must stop the
boot after the bootloader has completed its work. Trying to load
U-Boot too early can cause failure to boot. This is the method used by
Xilinx with its Zynq(MP) processors.
- Loading SPL with BOOT_DEVICE_RAM and breaking before SPL loads the
image to load U-Boot at the appropriate place. This can be a bit
tricky, because the load address is dependent on the header size. An
elf with symbols must also be used in order to stop at the appropriate
point. BOOT_DEVICE_SMH can be viewed as an extension of this process,
where SPL automatically stops and tells the host where to place the
image.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
In order to add filesystem support, we will need to be able to seek and
write files. Add the appropriate helper functions.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Instead of printing in what are now library functions, try to return a
numeric error code. This also adjust some functions (such as read) to
behave more similarly to read(2). For example, we now return the number
of bytes read instead of failing immediately on a short read.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
There's no point in using string constants for smh_open if we are just
going to have to parse them. Instead, use numeric modes. The user needs
to be a bit careful with these, since they are much closer semantically
to string modes used by fopen(3) than the numeric modes used with
open(2).
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This exports semihosting functions for use in other files. The header is
in include/ and not arm/include/asm because I anticipate that RISC-V may
want to add their own implementation at some point.
smh_len_fd has been renamed to smh_flen to more closely match the
semihosting spec.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
These files are spread all over the tree, so just use a regex. Orphaned
for now, since this is more of a "one-off" series. Though I'll be happy
to review patches.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This adds some instructions for enabling the debug uart, including the
correct address and clock rate.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This adds some additional info about booting from different sources,
including the correct switch positions.
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This converts the readme for this board to rST. I have tried not to
change any semantics from the original (though I did convert MB to M).
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
This converts the semihosting readme to rST. I have tried to make only
cosmetic changes, but I did fix up the first link (which was broken).
Signed-off-by: Sean Anderson <sean.anderson@seco.com>
The ARMv8-R64 architecture introduces optional VMSA (paging based MMU)
support in the EL1/0 translation regime, which makes that part mostly
compatible to ARMv8-A.
Add a new board variant to describe the "BASE-R64" FVP model, which
inherits a lot from the existing v8-A FVP support. One major difference
is that the memory map in "inverted": DRAM starts at 0x0, MMIO is at
2GB [1].
* Create new TARGET_VEXPRESS64_BASER_FVP target, sharing most of the
exising configuration.
* Implement inverted memory map in vexpress_aemv8.h
* Create vexpress_aemv8r defconfig
* Provide an MMU memory map for the BASER_FVP
* Update vexpress64 documentation
At the moment the boot-wrapper is the only supported secure firmware. As
there is no official DT for the board yet, we rely on it being supplied
by the boot-wrapper into U-Boot, so use OF_HAS_PRIOR_STAGE, and go with
a dummy DT for now.
[1] https://developer.arm.com/documentation/100964/1114/Base-Platform/Base---memory/BaseR-Platform-memory-map
Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
[Andre: rebase and add Linux kernel header]
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
[trini: Add MAINTAINERS entry for Peter]
So far the DRAM size for both the Juno and the FVP model were hardcoded
in our config header file. For the Juno this is fine, as all models have
8 GiB of DRAM, but the DRAM size can be configured on the model command
line.
Drop the fixed DRAM size setup, instead look up the size in the device
tree, that we now have for every board. This allows a user to inject
a DT with the proper size, and be able to use the full amount of DRAM.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
In preparation for the ARMv8-R64 FVP support, which has DRAM mapped at
0x0, generalise the page table generation, by using symbolic names for
the address ranges instead of fixed numbers.
We already define the base of the DRAM and MMIO regions, so just use
those symbols in the page table description. Rename V2M_BASE to the more
speaking V2M_DRAM_BASE on the way.
On the VExpress memory map, the address space right after 4GB is of no
particular interest to software, as the whole of DRAM is mapped at 32GB
instead. The first 2 GB alias to the lower 2GB of DRAM mapped below 4GB,
so we skip this part and map some more of the high DRAM, should anyone
need it.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Right now the defconfig the Arm VExpress64 boards disables quite some
standard commands, for apparently no good reasons (as image size is
hardly a concern here).
Remove the lines explicitly disabling those features, leaving it to
the U-Boot default settings to set them.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
So far the FVP model just supports booting through semihosting, so by
loading files from the host the model is running on. This allows for
quick booting of new kernels (or replacing DTBs), but prevents more
featureful boots like using UEFI.
Enable the distro_boot feature, and provide a list of possible boot
sources that U-Boot should check:
- For backwards compatibility we start with semihosting, which gets its
commands migrated from CONFIG_BOOTCOMMAND into the distro_boot
infrastructure. This is also slightly tweaked to fail graceful in case
the required files could not be found.
- Next we try to use a user provided script, that could be easily
placed into memory using the model command line.
- Since we gained virtio support with the enablement of OF_CONTROL,
let's check virtio block devices next. This is where UEFI boot can
be easily used, for instance by providing a distro installer .iso
file through virtio-blk.
- Networking is now provided by virtio as well, so enable the default
PXE and DHCP boot flows, mostly because we can.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
The defconfigs for the Arm Juno board and the FVP model are quite large,
setting a lot of platform-fixed variables like SYS_TEXT_BASE.
As those values are not really a user choice, let's provide default
values for them in our Kconfig file, so a lot of cruft can be removed
from the defconfig files.
This also moves the driver selection out of there, since this is again
not something a user should really decide on. Instead we allow users to
enable or disable subsystems, and select the appropriate drivers based
on that in the Kconfig file.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
The definition of the standard environment variables (kernel_addr_r and
friends) has been improved lately for the FVP model, but the Juno board
is still using some custom scheme.
Since we need to extend this to a third board soon, let's unify the
definition:
- Define the Juno addresses in the same generic way we do for the FVP
model, and move the actual variable setting out of the board #ifdef's.
- Add the missing addresses for a PXE file and a boot script.
- Cleanup some stale comments on the way.
As the FVP model doesn't have support for distro_boot quite yet, add
a dummy definition for now, to be replaced with the real thing later.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
The FVP base model is relying on a DT for Linux operation, so there is
no reason we would need to rely on hardcoded information for U-Boot.
Letting U-Boot use a DT will open up the usage of actual peripherals,
beyond the support for semihosting only.
Enable OF_CONTROL in the Kconfig, and use the latest dts files from
Linux. Depending on whether we use the boot-wrapper or TF-A, there is
already a DTB provided or not, respectively.
To cover the boot-wrapper, we add an arm64 Linux kernel header, which
allows the boot-wrapper to treat U-Boot like a Linux kernel. U-Boot will
find the pointer to the DTB in x0, and will use it.
Even though TF-A carries a DT, at the moment this is not made available
to non-secure world, so to not break users, we use the U-Boot provided
DTB copy in that case. For some reason TF-A puts some DT like structure
at the address x0 is pointing at, but that is very small and doesn't
carry any hardware information. Make the code to ignore those small DTBs.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
The Arm Fixed Virtual Platform (FVP) is a software model for an
artificial ARM platform, it is available for free on the Arm website[1].
Add the devicetree files for the latest RevC version, as we will need
them to enable OF_CONTROL for the vexpress_aemv8a_semi board.
This is a verbatim copy of the respective files from Linux v5.17-rc6,
which is unchanged from the v5.16 release.
[1] https://developer.arm.com/tools-and-software/simulation-models/fast-models
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
At the moment we define three "VExpress64" boards in arch/arm/Kconfig,
plus have a second Kconfig file in board/armltd/Kconfig.
One of those three boards is actually bogus (TARGET_VEXPRESS64_AEMV8A),
that stanza looks like being forgotten in a previous cleanup.
To remove the clutter from the generic Kconfig file, just define some
ARCH_VEXPRESS64 symbol there, enable some common options, and do the
board/model specific configuration in the board/armltd Kconfig file.
That allows to streamline and fine tune the configuration later, and
to also pull a lot of "non user choices" out of the defconfigs.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
This converts the following to Kconfig:
CONFIG_SYS_MONITOR_BASE
Note that for how this is re-used on some PowePC platforms, we introduce
CONFIG_SPL_SYS_MONITOR_BASE and CONFIG_TPL_SYS_MONITOR_BASE and use the
CONFIG_VAL macro to get the correct value at build time, in the code.
Signed-off-by: Tom Rini <trini@konsulko.com>
This converts the following to Kconfig:
CONFIG_NORFLASH_PS32BIT
Note that we also attempt to correct the behavior of the code here,
which had been testing for "NORFLASH_PS32BIT" which would never be set,
instead check for the now set "CONFIG_NORFLASH_PS32BIT", which results
in some behavior change.
Cc: TsiChung Liew <Tsi-Chung.Liew@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
The values CONFIG_SYS_USE_NANDFLASH and CONFIG_SYS_USE_MMC serve the
same purpose as CONFIG_SD_BOOT / CONFIG_NAND_BOOT so migrate to using
these switches instead as they're already in Kconfig.
Cc: Stelian Pop <stelian@popies.net>
Cc: Heiko Schocher <hs@denx.de>
Cc: Daniel Gorsulowski <daniel.gorsulowski@esd.eu>
Cc: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
In the case of M5373EVB we always had NANDFLASH_SIZE=16, so just use it
directly. In the case of M5329EVB we had not removed the rest of NAND
support when saying we didn't have NAND, so instead use that to key off
of rather than NANDFLASH_SIZE.
Cc: TsiChung Liew <Tsi-Chung.Liew@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
The value CONFIG_DB_784MP_GP is only used in the DDR code to refer to
CONFIG_TARGET_DB_MV784MP_GP so just use that second value directly.
Cc: Stefan Roese <sr@denx.de>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Stefan Roese <sr@denx.de>
