HI Matteo, I implemented the SDIO support for LPC43 some years ago and what helped me most was reading the SD/MMC specification, the LPC43 reference manual and enabling the NuttX SD/MMC debug messages.
There are many details to take care of: clock enable for the controller, interrupts, pins configuration, etc. Unfortunately, the BCM2711 doc is not good. You can start verifying the registers, maybe it is based on some SD/MMC core IP already supported by NuttX. BR, Alan On Mon, Sep 15, 2025 at 6:34 PM Matteo Golin <matteo.go...@gmail.com> wrote: > 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 > >> > > >
