Hi I've seen an EHCI debug dongle in the old wiki. I'm trying to build one for 2 purposes: debug a homebrew os/Shell and make it a new UEFI bootloader. However I don't know where to find further documentation or comments about this. I also dont' know what is the current or most up to date schematic to build the "sandwich" and what tracks cut and what not. I have bought those blue cypress FX2LP boards and I don't know how to check revisions. Also, I'dont know exactly what software can be used to control it. It would be desirable if one can send stop or install some breakpoints with Visual studio's debugger or WinDBG or GDB or something like that. thanks in advance for your advice.
Know I'm a bit late, but for me it was much easier to use FT232H-based USB board as a debug dongle. Initially I also wanted to build that FX2LP sandwich, but some confusion regarding the revisions (it's a bit tiresome to ask many sellers for a board revision in advance) and the need for revision-dependent soldering have scared me off. With a couple of FT232H from china/aliexpress and two USB extension cables for them, I didn't need to solder anything except their pin headers, so it was quite easy for me to get it working with coreboot - just by enabling CONFIG_USBDEBUG_DONGLE_FTDI_FT232H at its' config. But I haven't compared what is easier to use from a software side, for coreboot : FX2LP (which seems to have its' own firmware) or FT232H. It seems that you don't have a coreboot-supporting board, but maybe you could still use the sources from /coreboot/src/drivers/usb/gadget.c for your OS.
On Sun, Oct 13, 2019 at 1:28 AM alejandro.estay@gmail.com wrote:
Hi I’ve seen an EHCI debug dongle in the old wiki. I’m trying to build one for 2 purposes: debug a homebrew os/Shell and make it a new UEFI bootloader. However I don’t know where to find further documentation or comments about this. I also dont’ know what is the current or most up to date schematic to build the “sandwich” and what tracks cut and what not. I have bought those blue cypress FX2LP boards and I don’t know how to check revisions. Also, I’dont know exactly what software can be used to control it. It would be desirable if one can send stop or install some breakpoints with Visual studio’s debugger or WinDBG or GDB or something like that. thanks in advance for your advice.
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I do not mean to hijack the question but is a hardware usb to serial device required?
The wiki briefly mentions "usb_debug_io.c" with a link to an old trac ticket. Could a second device connected via usb only read the logs? I am curious on the feasibility of attaching an Android phone/tablet with an app that could easily read coreboot debug information.
On 10/13/19 3:27 AM, Mike Banon wrote:
Know I'm a bit late, but for me it was much easier to use FT232H-based USB board as a debug dongle. Initially I also wanted to build that FX2LP sandwich, but some confusion regarding the revisions (it's a bit tiresome to ask many sellers for a board revision in advance) and the need for revision-dependent soldering have scared me off. With a couple of FT232H from china/aliexpress and two USB extension cables for them, I didn't need to solder anything except their pin headers, so it was quite easy for me to get it working with coreboot - just by enabling CONFIG_USBDEBUG_DONGLE_FTDI_FT232H at its' config. But I haven't compared what is easier to use from a software side, for coreboot : FX2LP (which seems to have its' own firmware) or FT232H. It seems that you don't have a coreboot-supporting board, but maybe you could still use the sources from /coreboot/src/drivers/usb/gadget.c for your OS.
On Sun, Oct 13, 2019 at 1:28 AM alejandro.estay@gmail.com wrote:
Hi I’ve seen an EHCI debug dongle in the old wiki. I’m trying to build one for 2 purposes: debug a homebrew os/Shell and make it a new UEFI bootloader. However I don’t know where to find further documentation or comments about this. I also dont’ know what is the current or most up to date schematic to build the “sandwich” and what tracks cut and what not. I have bought those blue cypress FX2LP boards and I don’t know how to check revisions. Also, I’dont know exactly what software can be used to control it. It would be desirable if one can send stop or install some breakpoints with Visual studio’s debugger or WinDBG or GDB or something like that. thanks in advance for your advice.
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On 13.10.19 16:40, Tom Hiller wrote:
The wiki briefly mentions "usb_debug_io.c" with a link to an old trac ticket. Could a second device connected via usb only read the logs? I am curious on the feasibility of attaching an Android phone/tablet with an app that could easily read coreboot debug information.
For EHCI debug, the basic requirements are that it's a high-speed capable device and that you can configure and use it with <= 8 byte transfers.
Usually this applies to Android devices and some have been used already for debugging. You need the `g_dbgp` gadget driver. This driver is reported to not always work, however... a workaround could be to use `g_serial` and add some support code to the debug target.
Nico
A not on EHCI debug, the screwdriver on Beaglebone black would need some loving but works:
https://github.com/osresearch/heads/issues/541#issuecomment-481513900
On 10/14/19 10:53 AM, Nico Huber wrote:
On 13.10.19 16:40, Tom Hiller wrote:
The wiki briefly mentions "usb_debug_io.c" with a link to an old trac ticket. Could a second device connected via usb only read the logs? I am curious on the feasibility of attaching an Android phone/tablet with an app that could easily read coreboot debug information.
For EHCI debug, the basic requirements are that it's a high-speed capable device and that you can configure and use it with <= 8 byte transfers.
Usually this applies to Android devices and some have been used already for debugging. You need the `g_dbgp` gadget driver. This driver is reported to not always work, however... a workaround could be to use `g_serial` and add some support code to the debug target.
Nico _______________________________________________ coreboot mailing list -- coreboot@coreboot.org To unsubscribe send an email to coreboot-leave@coreboot.org
On 13.10.2019 10:27, Mike Banon wrote:
With a couple of FT232H from china/aliexpress and two USB extension cables for them
Actually, even just one FT232H plus one USB-UART (pl2303, for example) will work.
On Sun, Oct 13, 2019 at 1:28 AM alejandro.estay@gmail.com wrote:
Hi I’ve seen an EHCI debug dongle in the old wiki. I’m trying to build one for 2 purposes: debug a homebrew os/Shell and make it a new UEFI bootloader. However I don’t know where to find further documentation or comments about this. I also dont’ know what is the current or most up to date schematic to build the “sandwich” and what tracks cut and what not. I have bought those blue cypress FX2LP boards and I don’t know how to check revisions. Also, I’dont know exactly what software can be used to control it. It would be desirable if one can send stop or install some breakpoints with Visual studio’s debugger or WinDBG or GDB or something like that. thanks in advance for your advice.
Hi
I created the original FX2LP dongle sandwich, crafting together pieces from different fx2lib sources back in 2013. I think my repository regressed (no longer built) already in 2014-2015 after some sdcc update and I never had interest to maintain that; coreboot devs had switched to USB gadgets like BBB screwdriver and dual-FT232H.
There was further work [1] linked in wiki that claims to work as a compatible net20dc replacement with windows kernel debugger. I never built or run that firmware. I may still have the hardware somewhere but I don't remember them having any distinct PCB revision silkscreens printed, you just need to trace the pins. The FX2LP boards I had were actually relabeled FX2, which might also may break net20dc compatibility.
I would go with one of the other non-FX2LP approaches instead:
- use pre-built beaglebone black screwdriver image, route USB gadget (g_dbpg) to TCP (how to make it appear as virtual COM port for WinDBG I have no clue of) - some phone or devboard with USB OTG 2.0 operating in device mode, otherwise same as above - in case you develop with some TianoCore / EDK, which claims net20dc support, make it compatible with FT232H, it should be just a matter of sending couple different USB packets [2]
[1] https://github.com/night199uk/fx2lib/pull/2 [2] https://review.coreboot.org/c/coreboot/+/10063
Kyösti
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alejandro.estay＠gmail.com -
Evgeny Zinoviev -
Insurgo -
Kyösti Mälkki -
Mike Banon -
Nico Huber -
Tom Hiller