Hi everyone, Now that I2C has been tackled, I am moving on to SDIO interfaces so the SD card can be interacted with from NuttX.
The NuttX SDIO documentation is a little bare, and I'm not the most familiar with SDIO. Does anyone have any recommendations for implementations to look at (besides the STM32 one that is linked in the docs), resources to read (any blog posts from when you ported SDIO) or advice in general? It would be much appreciated. Thank you, Matteo On Fri, Sep 5, 2025, 11:15 AM Matteo Golin <matteo.go...@gmail.com> wrote: > Got another response from my earlier request to Raspberry Pi through their > website: > > Hi Matteo > > > >> Thanks for getting in touch. We don't actually have any more >> documentation that we can release on this. My usual recommendation is for >> SW people to take a look at the Linux drivers to get a closer understanding >> of how the HW works. Not ideal, but the best I can offer. > > > So I guess everyone is telling us the same thing! > > > On Mon, Sep 1, 2025 at 3:49 PM Tomek CEDRO <to...@cedro.info> wrote: > >> Sure! Public now :-) >> Tomek >> >> On Mon, Sep 1, 2025 at 9:24 PM Matteo Golin <matteo.go...@gmail.com> >> wrote: >> > >> > I have populated the RPi 4B project with some starting issues to tackle >> for >> > the 4B implementation. I see that the project is marked as private; is >> > there any way to make it visible to potential contributors just visiting >> > the GitHub page? I think if they can see a list of issues in one place >> when >> > they go to the page it might help. >> > >> > Thanks, >> > Matteo >> > >> > On Mon, Sep 1, 2025 at 3:02 PM Tomek CEDRO <to...@cedro.info> wrote: >> > >> > > Thank you Linguini, good luck and have fun! :-) >> > > Tomek >> > > >> > > On Mon, Sep 1, 2025 at 8:48 PM Matteo Golin <matteo.go...@gmail.com> >> > > wrote: >> > > > >> > > > To update the community, we've been told by Gordon that the Pi >> Foundation >> > > > doesn't have any documentation for the chip beyond what was written >> in >> > > the >> > > > peripheral datasheet. Broadcom themselves has written the Linux >> drivers >> > > and >> > > > Raspberry Pi has only made some slight bug fixes, etc. We've been >> > > suggested >> > > > to read the source to discover undocumented registers/configuration >> > > options. >> > > > >> > > > I plan to still continue with the port until the feature set on >> NuttX is >> > > > equal or greater to what is available on QNX. I at least want to get >> > > > Ethernet and some graphics running after the base peripheral set >> (I2C, >> > > SPI, >> > > > UART) are supported. >> > > > >> > > > Matteo >> > > > >> > > > On Sun, Aug 31, 2025 at 6:10 PM Matteo Golin < >> matteo.go...@gmail.com> >> > > wrote: >> > > > >> > > > > Very interesting Sebastian. I got that impression from Broadcom >> when I >> > > was >> > > > > initially trying to port NuttX to the Pi. The inability to submit >> > > forms on >> > > > > their website seems like it might be by design... >> > > > > >> > > > > I'm hopeful the Raspberry Pi Foundation will have something more >> for >> > > us to >> > > > > work with, they seem more positive to FOSS. Otherwise I will still >> > > continue >> > > > > with reverse engineering until at least the point where the >> > > functionality >> > > > > driver-wise is on par with QNX. >> > > > > >> > > > > On Sun, Aug 31, 2025, 10:46 AM Tomek CEDRO <to...@cedro.info> >> wrote: >> > > > > >> > > > >> James Dougherty contacted us with Gordon Hollingworth from >> Raspberry >> > > > >> Pi Foundation recently :-) We are waiting for response :-) I >> really >> > > > >> hope we can get some sort of documentation and/or code samples to >> > > > >> write high quality NuttX port for the big raspberries :-) >> > > > >> >> > > > >> Open-Source matters even more in this crazy world. Thanks for >> > > > >> interesting article Sebastien! Personally I think we should >> focus only >> > > > >> on vendors that support Open-Source. What is the reason for >> bumping >> > > > >> sales for companies that in the end can sue you for reversing? :D >> > > > >> >> > > > >> Have a good day folks :-) >> > > > >> Tomek >> > > > >> >> > > > >> >> > > > >> >> > > > >> On Sun, Aug 31, 2025 at 10:15 AM Sebastien Lorquet < >> > > sebast...@lorquet.fr> >> > > > >> wrote: >> > > > >> > >> > > > >> > Hello, >> > > > >> > >> > > > >> > I just found this interesting document: >> > > > >> > >> > > > >> > >> > > > >> >> > > >> https://fastcode.io/2025/08/30/the-69-billion-domino-effect-how-vmwares-debt-fueled-acquisition-is-killing-open-source-one-repository-at-a-time/ >> > > > >> > >> > > > >> > In a summary, if you expect anything cool from broadcom: dont. >> > > > >> > >> > > > >> > go go go reverse engineering! >> > > > >> > >> > > > >> > Sebastien >> > > > >> > >> > > > >> > >> > > > >> > On 8/29/25 15:37, Tomek CEDRO wrote: >> > > > >> > > No response from #infra@slack, I just sent request to >> > > > >> > > dev@community.apache mailing list maybe someone can reply >> over >> > > there >> > > > >> > > :-) >> > > > >> > > >> > > > >> > > >> https://lists.apache.org/thread/n9y5vrvjm23npwgbr45f7zq5ys5l8dok >> > > > >> > > >> > > > >> > > We should also know the official stance from Broadcom and RPI >> > > > >> Foundation :-) >> > > > >> > > >> > > > >> > > Thanks :-) >> > > > >> > > Tomek >> > > > >> > > >> > > > >> > > On Thu, Aug 28, 2025 at 9:35 PM Tomek CEDRO < >> to...@cedro.info> >> > > wrote: >> > > > >> > >> I just asked question at #asfinfra / slack, maybe someone >> can >> > > help >> > > > >> > >> there or recommend someone who can, waiting for response :-) >> > > > >> > >> >> > > > >> > >> For a good start you can contact Broadcom and RaspberryPi >> > > Foundation, >> > > > >> > >> introduce yourself as Apache NuttX RTOS developer that want >> to >> > > port >> > > > >> > >> NuttX to rPI boards, and just ask if DataSheets are >> available >> > > :-) We >> > > > >> > >> will know then first hand if this is possible or are there >> any >> > > > >> > >> problems / requirements :-) >> > > > >> > >> >> > > > >> > >> You can ask for 4B and probably Zero-2W SoC documentation >> these >> > > seems >> > > > >> > >> most popular nowadays :-) >> > > > >> > >> >> > > > >> > >> Thanks :-) >> > > > >> > >> Tomek >> > > > >> > >> >> > > > >> > >> >> > > > >> > >> >> > > > >> > >> On Thu, Aug 28, 2025 at 8:45 PM Matteo Golin < >> > > matteo.go...@gmail.com> >> > > > >> wrote: >> > > > >> > >>> Hi Tomek, >> > > > >> > >>> >> > > > >> > >>> Thanks so much! I actually hadn't thought of that, maybe we >> > > could >> > > > >> ask for >> > > > >> > >>> help from the foundation. Do you know who's the best point >> of >> > > > >> contact for >> > > > >> > >>> that? >> > > > >> > >>> >> > > > >> > >>> I know Linux must have received the datasheets to make >> > > Raspberry Pi >> > > > >> OS. No >> > > > >> > >>> offence to NuttX, but Linux is pretty popular in >> comparison. If >> > > > >> Broadcom or >> > > > >> > >>> Raspberry Pi would release us some information that would >> be an >> > > > >> immense >> > > > >> > >>> help. I suspect there was some kind of deal with the Linux >> group >> > > > >> but I have >> > > > >> > >>> no idea. I believe even QNX didn't have access to the >> datasheets >> > > > >> and rather >> > > > >> > >>> just reverse engineered the Linux drivers. >> > > > >> > >>> >> > > > >> > >>> Matteo >> > > > >> > >>> >> > > > >> > >>> On Thu, Aug 28, 2025, 12:42 PM Tomek CEDRO < >> to...@cedro.info> >> > > > >> wrote: >> > > > >> > >>> >> > > > >> > >>>> On Tue, Aug 26, 2025 at 10:05 PM Matteo Golin < >> > > > >> matteo.go...@gmail.com> >> > > > >> > >>>> wrote: >> > > > >> > >>>>> I2C still needs some work unfortunately. However, I agree >> > > with you >> > > > >> > >>>>> generally. Personally, I think HDMI, networking >> (including >> > > WiFi >> > > > >> and BLE) >> > > > >> > >>>>> and some kind of interaction with storage (eMMC or SD >> card) >> > > are >> > > > >> the most >> > > > >> > >>>>> important. Unfortunately, those are likely going to be >> the >> > > most >> > > > >> difficult >> > > > >> > >>>>> because of the lack of documentation on the peripherals. >> It is >> > > > >> definitely >> > > > >> > >>>>> not an impossible task, but it will be challenging. >> Hence my >> > > > >> request for >> > > > >> > >>>>> creating the new project roadmap, so maybe some >> discoveries >> > > can be >> > > > >> > >>>>> documented there and more eyes can get on the RPi >> > > implementation. >> > > > >> > >>>> The lack of documentation is a real pain, and known issue >> for >> > > > >> years in >> > > > >> > >>>> many areas, but some vendors are especially famous for >> that. >> > > > >> > >>>> >> > > > >> > >>>> Considering someone wants to create Open-Source drivers >> for >> > > free >> > > > >> and >> > > > >> > >>>> bring customers to the vendor. >> > > > >> > >>>> >> > > > >> > >>>> Maybe we could ask Apache Foundation for help in obtaining >> > > required >> > > > >> > >>>> datasheets? :-) >> > > > >> > >>>> >> > > > >> > >>>> -- >> > > > >> > >>>> CeDeROM, SQ7MHZ, http://www.tomek.cedro.info >> > > > >> > >>>> >> > > > >> > >> >> > > > >> > >> >> > > > >> > >> -- >> > > > >> > >> CeDeROM, SQ7MHZ, http://www.tomek.cedro.info >> > > > >> > > >> > > > >> > > >> > > > >> >> > > > >> >> > > > >> >> > > > >> -- >> > > > >> CeDeROM, SQ7MHZ, http://www.tomek.cedro.info >> > > > >> >> > > > > >> > > >> > > >> > > >> > > -- >> > > CeDeROM, SQ7MHZ, http://www.tomek.cedro.info >> > > >> >> >> >> -- >> CeDeROM, SQ7MHZ, http://www.tomek.cedro.info >> >
