Hi Stefan, On Tue, Feb 28, 2017 at 07:37:08PM +0100, Stefan Koch wrote: > 2017-02-22 17:11 GMT+01:00 Daniel Golle <dan...@makrotopia.org>: > > 4) Write a proper, platform agnostic driver to connect the SLIC via > > SPI, PCM, I2C or whatever and add a simple DAHDI driver for it. Then > > have asterisk do the transcoding (maybe some ASM optimization to make > > it even take advantage of MIPS DSP instructions) and rely in the kernel > > scheduler to share the load nicely between the two CPUs. > > > > That'd be much cleaner and will even be reusable on other targets like > > ramips or ar71xx (where we also got devices with SLICs) plus we can > > support non-Infenion SLIC and escape the (intentional?) vendor-lock of > > that shady Lantiq implementation. > > > I think It would be a nice thing to have a native Linux SLIC driver. > For FXS it may be easier than to implement DECT and other things that > the firmware does support. > Does the SLIC support the DECT functionality or is it somewhere else?
Nah, SLICs a rather simple AD/DA things with on-hook/off-hook detection plus some high-voltage AC stuff going on to ring the bell. Not crazily complicated, but also not exactly trivial. Caller-ID, ADSI, DTMF and all that is taken care of purely in software by DAHDI. Support for SLICs mostly depends on platform support for high-speed SPI and PCM from what I understand, the rest should not be that hard... Datasheets are also not hard to find. DECT is a completely different story: Most devices I've seen so far use Dialog's SC14452 connected via SPI and PCM. Sometimes a small FPGA is used, supposedly serving as a PCM de-multiplexer, so SLICs and DECT can be used simultanously on the same PCM bus. Supporting that might give us a serious headache unless someone finds a good way to hack that into the kernel (obviously, we'll have to reverse-engineer this first by sniffing the PCM bus before and after it hits the FPGA) For the more simple cases and/or more up-to-date boards, I put some effort into porting Osmocom's DECT stack to OpenWrt long time ago: https://lists.openwrt.org/pipermail/openwrt-devel/2014-June/026274.html But at the time there was no support for hardware-supported SPI on Lantiq nor any support for PCM/I2S stuff, thus I was stuck with that really old PCMCIA gear It'd be great if someone could actually forward-port and test-run this on some x86-32 gear with a PCMCIA slot and the COM-ON-AIR card flying around in at Raumfahrtagentur in Berlin. Some weird devices actually use a Cologne Chip HFC-4S connected via SPI and then drive the analog ports and DECT indirectly via BRI. Those boxes are more like a low-end ISDN PBX with built-in DECT and analog ports. Supporting them should not be too difficult as datasheets as well as drivers (as part of DAHDI) for Cologne Chip HFC are publicly available. > > I have never detected the VPE specific command line at AVM > Fritz!Boxes. Do you know how they do it? > The Easybox 904 uses the same VPE approach by loading the firmware, > reduce system memory and so on. But this one is a bit more simplified. No idea what AVM is doing. I mostly looked at Arcadyan and AudioCodes boards... Cheers Daniel _______________________________________________ Lede-dev mailing list Lede-dev@lists.infradead.org http://lists.infradead.org/mailman/listinfo/lede-dev
