W dniu 25.03.2025 o 08:14, Svyatoslav Ryhel pisze:
пн, 24 бер. 2025 р. о 22:01 Artur Kowalski<arturkow2...@gmail.com> пише:
Hello
Thanks for quick response. I know UARTD is the dedicated UART for
debugging on TF101, but exposing UART over microSD
is a handy trick useful for development. As I'm doing development on
It is a handy trick indeed, but it is still just a trick and not smth
that fits mainline. Maximum I can propose is picking funcmux change
along with uart over sd section in transformer t20 documentation.
this tablet (bringing U-Boot's UEFI support and latest
Linux), and also still using the device on old OS I'd like to avoid
disassembling and reassembling it over and over again.
I am not sure what are you doing but TF101 has full support of U-Boot
as primary bootloader along with full mainline support till 6.14
including. It uses extlinux boot method and needs no intermediates or
chainloading.
If you wish to use U-Boot for tethered booting that is perfectly fine as well.
Booting with UEFI didn't work, I have solved that problem locally by
forcing LMB allocator
to not allocate at 0x0, any platform where RAM starts at 0x0 could be
affected by it. Soon I
will send patches. I want to use UEFI so that I can take advantage
systemd-boot features such
as one-time boot for system updates, some other software I plan to use
also depends on UEFI.
Also, with extlinux I can't use verified boot, but, eventually I plan to
program PKC and have full
secure boot with hardware RoT.
When bringing UEFI support I also made some changes so that U-Boot works
with
CONFIG_OF_UPSTREAM, I also plan to upstream the patches soon.
Linux lacks GPS support and possibly camera, also sorry for my mistake,
I meant a complete Linux
distro rather than the kernel only, which is lacking GPU acceleration.
Also, when running preemptible
kernel I can see multiple "scheduling while atomic" errors and random
system freezes under load.
Others too may find the feature useful e. g. to avoid having to solder
which requires specialized equipment, skills and
is potentially dangerous for the board. Also, there already seems to be
support for that on Sunxi platforms through
CONFIG_UART0_PORT_F.
Apart from pinmux changes, would it be acceptable to include an option
to allow switching UARTA mux to
SDB/SDD (currently this has to be selected from board's Kconfig file).
Doing so would allow to enable UART
over microSD without patching U-Boot's source without changing any
existing configuration. Then I would
keep DTS overlays and config changes local.
I am fine with any changes which may simplify debugging for you as
long as they do not invade into completed device configuration without
a valid reason. Device must expose a dedicated UART for debug, not a
mux which breaks some device features just because you do not want to
contain them locally.
For example, patches which add UART-E support along with funcmux
change which exposes uart-e over usd were accepted, but patch similar
to yours which would reconfigure usd to uart for surface rt or p880
would be rejected.
I've sent v2, which besides few other fixes, adds dedicated Kconfig
option for enabling UART. If disabled, the config is the same.
Also, today, after running U-Boot with debug enabled, I discovered some
failed assertions in pinmux code probably
caused by my changes, I will get that fixed before sending v2.
Turns out it was something else. I've sent a patch to fix that:
https://patchwork.ozlabs.org/project/uboot/patch/20250330211153.RFC.1.Iebf436d41ff5f52c0b11aaf9e8f98d6a2d4d56bc@changeid/
Best regards
Artur Kowalski
W dniu 18.03.2025 o 09:54, Svyatoslav Ryhel pisze:
вт, 18 бер. 2025 р. о 10:31 Artur Kowalski<arturkow2...@gmail.com> пише:
The first patch in the series brings general pinmux support for exposing
UART over SDB/SDD pins on T20. The following patches bring support
Transformer T20 allowing to enable UART over uSD by setting
CONFIG_TEGRA_ENABLE_UARTA=y
CONFIG_DEVICE_TREE_INCLUDES="tegra20-asus-transformer-uart-usd.dtsi"
Similarily, support for UART over uSD could be brought to Ventana which
has uSD on the same pins as TF101, and other Ventana-based boards.
Hey there, thank you for looking into U-Boot for Tegra. If something I
will say hurts or offends you, I am sorry it was not intentional.
Anyway, apart funcmux changes, all other changes you propose are
redundant. Asus dedicated uart for logging and console is UARTD any
other uart configuration must not be added since it will disrupt
existing configuration. If you need uart and cannot resolve an issue
without it you can always solder to uart-d or locally mux sd to uart
console fix your issue and remove it. Uart is not intended way to
interact with Asus TF101 and doesn't need to be exposed, panel and
fastboot console are and can be used to resolve most of issues.
Best regards,
Svyatoslav R.
Artur Kowalski (4):
tegra: add funcmux for exposing UART over uSD slot on Tegra 20
tegra: respect CONFIG_TEGRA_ENABLE_UART* options on Transformer T20
ARM: tegra: expose UART-A over uSD on Transformer T20
board: asus: transformer: add DTSI file for enabling UART over uSD
slot
.../tegra20-asus-transformer-uart-usd.dtsi | 31 +++++++++++++++++++
arch/arm/include/asm/arch-tegra20/funcmux.h | 1 +
arch/arm/mach-tegra/board.c | 4 ++-
arch/arm/mach-tegra/tegra20/Kconfig | 4 +++
drivers/pinctrl/tegra/funcmux-tegra20.c | 9 +++++-
include/configs/transformer-t20.h | 10 ++++++
6 files changed, 57 insertions(+), 2 deletions(-)
create mode 100644 arch/arm/dts/tegra20-asus-transformer-uart-usd.dtsi
--
2.48.1
