Hi,
I wrote an Genode application for the Pololu Maestro Mini Servo Controller in Genode (https://github.com/702nados/genode-pololuServoController).
I'm using the usb_drv (dde_linux) and the usb_terminal (pl2303) for read and write commands. It runs flawlessly on PandaBoard (foc_panda).
Next, I want to use it with Linux as kernel (linux_x86). If I try to run the resulting application, the usb_drv component throws the following error:
no route to service "Platform"
So, is it possible to compile and run the intended application without modifications?
If I want to use the linux devices (e.g. usb), who can I achieve this in code?
In general, the following shows the intended architecture:
--------------------- ServoController | --------------------- Genode | --------------------- Linux | --------------------- Hardware | ---------------------
Best regards Daniel
Hi Daniel,
Next, I want to use it with Linux as kernel (linux_x86). If I try to run the resulting application, the usb_drv component throws the following error:
no route to service "Platform"
So, is it possible to compile and run the intended application without modifications?
If I want to use the linux devices (e.g. usb), who can I achieve this in code?
on base-linux, the USB driver resides in the Linux kernel. Genode's usb_drv cannot be used. However, your 'ServoController' doesn't actually need a USB driver but merely a terminal session. Your scenario relies on the usb_drv + usb_terminal in this respect. On Linux, I would use a completely different terminal service.
The best approach would be to have a Genode component - let's call it lx_terminal - that opens a character device on Linux and provides a terminal service by forwarding all 'read' and 'write' operations to the Linux device. This component could then be used with any arbitrary Linux device, on particular your USB-serial device that would normally appear at /dev/ttyUSB0.
The resulting picture would look like this:
ServoController --------------------------------- lx_terminal | -------.-----------' | | Genode -------V------------------------- /dev/ttyUSB0 Linux kernel --------------------------------- Hardware
Unfortunately, the lx_terminal component does not exist yet. But similar components for other Genode services exist, which you could use blue print:
* os/src/drivers/nic/spec/linux/ (provides a NIC session via a Linux tap device)
* os/src/server/lx_fs/ (provides a file-system session by accessing the Linux file system)
* os/src/drivers/framebuffer/spec/sdl (provides a framebuffer and input session via libSDL)
* os/src/drivers/audio/spec/linux (provides an audio-out session via ALSA)
Actually, when looking at this list, it might be even possible to emulate the lx_terminal component by combining the lx_fs with the file_terminal component (gems/src/server/file_terminal). But a dedicated lx_terminal component would certainly be nicer.
Cheers Norman
PS: In principle, it would be interesting to use Genode's device drivers on top of the Linux kernel by facilitating Linux' user-level device-driver infrastructure. This would clear the way to run your entire scenario including the USB driver on Linux. We have briefly documented this idea of "microkernelizing Linux" at http://genode.org/about/challenges#Platforms
Hi Norman,
thank you for the fast and detailed response (and the interesting idea :) ).
Best regards Daniel
-- Daniel Krefft MSc. Wissenschaftlicher Mitarbeiter
Technische Universitaet Muenchen Fakultaet fuer Informatik Lehrstuhl fuer Betriebssysteme
Arcisstrasse 21 80333 Muenchen
Tel. +49 89 289 18791
daniel.krefft@...256... www.os.in.tum.de/personen/krefft
________________________________________ Von: Norman Feske <norman.feske@...1...> Gesendet: Mittwoch, 6. Juli 2016 08:56 An: genode-main@lists.sourceforge.net Betreff: Re: Genode/Linux USB Application
Hi Daniel,
Next, I want to use it with Linux as kernel (linux_x86). If I try to run the resulting application, the usb_drv component throws the following error:
no route to service "Platform"
So, is it possible to compile and run the intended application without modifications?
If I want to use the linux devices (e.g. usb), who can I achieve this in code?
on base-linux, the USB driver resides in the Linux kernel. Genode's usb_drv cannot be used. However, your 'ServoController' doesn't actually need a USB driver but merely a terminal session. Your scenario relies on the usb_drv + usb_terminal in this respect. On Linux, I would use a completely different terminal service.
The best approach would be to have a Genode component - let's call it lx_terminal - that opens a character device on Linux and provides a terminal service by forwarding all 'read' and 'write' operations to the Linux device. This component could then be used with any arbitrary Linux device, on particular your USB-serial device that would normally appear at /dev/ttyUSB0.
The resulting picture would look like this:
ServoController --------------------------------- lx_terminal | -------.-----------' | | Genode -------V------------------------- /dev/ttyUSB0 Linux kernel --------------------------------- Hardware
Unfortunately, the lx_terminal component does not exist yet. But similar components for other Genode services exist, which you could use blue print:
* os/src/drivers/nic/spec/linux/ (provides a NIC session via a Linux tap device)
* os/src/server/lx_fs/ (provides a file-system session by accessing the Linux file system)
* os/src/drivers/framebuffer/spec/sdl (provides a framebuffer and input session via libSDL)
* os/src/drivers/audio/spec/linux (provides an audio-out session via ALSA)
Actually, when looking at this list, it might be even possible to emulate the lx_terminal component by combining the lx_fs with the file_terminal component (gems/src/server/file_terminal). But a dedicated lx_terminal component would certainly be nicer.
Cheers Norman
PS: In principle, it would be interesting to use Genode's device drivers on top of the Linux kernel by facilitating Linux' user-level device-driver infrastructure. This would clear the way to run your entire scenario including the USB driver on Linux. We have briefly documented this idea of "microkernelizing Linux" at http://genode.org/about/challenges#Platforms
-- Dr.-Ing. Norman Feske Genode Labs
http://www.genode-labs.com · http://genode.org
Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth
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