Allwinner D1s/F133 notes

Q&A

Q: Bare-metal debugging possible?

Apparently: https://linux-sunxi.org/Allwinner_Nezha#JTAG – but what is the physical connection?

Q: What is the pre-flashed image in MangoPi MQ?

A: None: there is no persistent memory besides the SD card

Q: What is BOOT0?

A: it is the Allwinner SPL (Secondary Program Loader).

It is something that you link into your boot image. Apparently U-Boot obsoletes it: https://github.com/smaeul/u-boot/releases/tag/d1-2022-10-31 (but is it in mainline U-Boot too?)

Searching for get_pmu_exist (appears in boot0 output) yields a lot of other interesting links.

Some MQ-specific configuration here: https://github.com/amessier/sun20i_d1_spl/commit/234b2e905a88f29db91768a25ad1c779594a598e

Q: How to copy .img (IMAGEWTY) files to SD card on Linux?

A: Must use OpenixCard dump feature.

Q: Is OpenSBI needed for bare-metal development?

Not really, it’s a way to have platform firmware in H-mode and OS or hypervisor in S-mode. Bare-metal code can just run in M-mode directly.

Q: xfel vs sunxi-fel

sunxi-fel -> Invalid command ddr

I guess it doesn’t support the F133

Q: Can switch between RV64 and RV32

No, the C906 core doesn’t support this, neither in S- or U-mode.

Q: In light of above, can we at least convince GCC that 32-bit pointers would do?

There is a proposal: https://lpc.events/event/17/contributions/1475/attachments/1186/2442/rv64ilp32_%20Run%20ILP32%20on%20RV64%20ISA.pdf

Is it ratified or at least widely accepted, though?

A future version of this specification may define an ILP32 ABI for the RV64 ISA, but currently this is not a supported operating mode

Might need to build toolchain from source. TBC

• https://lwn.net/Articles/932290/
• https://lwn.net/Articles/951187/
• https://wiki.gentoo.org/wiki/RISC-V_ABIs
• https://gcc.gnu.org/onlinedocs/gcc/RISC-V-Options.html

TV Encoder (TVE)

• clock source? PLL; must be 216 MHz

• test bars?

• https://forum.armbian.com/topic/46922-orangepi-zero-2w-tv-out/

• https://forum.armbian.com/topic/6582-orange-pi-zero-h2h3-tv-out-on-mainline-working/

• https://github.com/robertojguerra/orangepi-zero-full-setup/blob/main/README2.md

• https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/sun4i/sun4i_tv.c

Boot images

Tina Linux

• https://github.com/paulwratt/mangopi-sbc-Tina-Linux but the links are down
• tina_d1-nezha_uart0_f133_nolcd.img, burned with PhoenixCard (Work Type = Start up)
• result: success, console on UART0 (P3 pins 7 & 8) at 115200 baud

RT-Thread example

• https://github.com/Cathy-lulu/MangoPi-Nezha-MQ
• BOOT0, RT-Thread
• result: partial success, output on UART0 (P3 pin 7) at 500000 baud, errors out late in boot process

mangopi-mq-riscv-2023-1-serial-console.img

• https://github.com/ikruusa/mangopi-mq-riscv-images
• U-Boot 2023.01-rc1, OpenSBI v1.3, Linux version 6.6.0-rc7
• result: success, console on UART3 (header not mounted by default) at 115200 baud

mq-r-f133-rtl8189fs-5113-dns-uart0.img

• from https://mangopi.org/mangopi_mq, but filename suggests it’s for the MQ-R
• couldn’t get it to work, no output on UART0 header
• might have messed up the copy process

D1s bare-metal code

• XFEL payloads
  • init for PLL etc.; sdelay function
  • examples of init & use of UART, SPI
  • DDR2 init (disassembled code)
• D1 SPL
  • drivers for many peripherals, including DRAM init in C
  • distilled version: https://github.com/smaeul/u-boot/blob/d1-2022-10-31/drivers/ram/sunxi/mctl_hal-sun20iw1p1.c
• what are these? https://github.com/smaeul/sun20i_d1_spl/blob/mainline/drivers/dram/sun20iw1p1/lib-dram/t-head-compat.inc
• Assembly examples (blinky, GPIO)
• Xboot – not clear what is the point of it

Related: Bare-metal code for D1-H (similar SoC)

• https://github.com/bigmagic123/d1-nezha-baremeta
  • a bunch of demos: UART, JTAG, vector instructions, timer, PLINT, watchdog
  • documentation is in Mandarin only
• https://github.com/chaoyangnz/mpi-d1
• https://github.com/Ouyancheng/FlatHeadBro