Thanks Alan! Maybe I will reach out to Arasan, could have more luck than with Broadcom, but I doubt it.
I'll take a look at these documents! Thanks again, Matteo On Tue, Sep 16, 2025, 11:00 AM Alan C. Assis <acas...@gmail.com> wrote: > Hi Matteo, > > Please that a look: > https://www.arasan.com/products/sd-emmc/sdio-3-0-device/ > > There is an option to Download (request) the Datasheet from that page, but > you can access it directly here: > > https://www.arasan.com/wp-content/uploads/2016/05/3MCR-Total-IP-Solution.pdf > > This document is more about the IP core details, but could give you more > understanding about internal block of the SDIO controller (its FIFO, > initialization diagram, etc) > > You can also try to find the original > SD3.0_Host_AHB_eMMC4.4_Usersguide_ver5.9_jan11_10.pdf cited in Raspberry > documentation. > > BR, > > Alan > > > > On Tue, Sep 16, 2025 at 11:17 AM Matteo Golin <matteo.go...@gmail.com> > wrote: > > > Hi Alan, > > > > Thank you for the tips! Yes, SDIO looks pretty involved compared to SPI > or > > I2C. I'll try reading the specification like you suggested. > > > > The BCM2711 datasheet doesn't document it at all, however the EMMC > > interface is supposedly the exact same from the BCM2835 and the registers > > there are at least documented. All I know is that it is using an > interface > > by Arasan. I'm not as familiar with NuttX, but if this at all looks like > > something that's already been supported, please let me know. In the > > meantime, I'll look through the SDIO implementations to check: > > > https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf > > (page 65) > > > > Thanks again! > > Matteo > > > > On Tue, Sep 16, 2025 at 9:49 AM Alan C. Assis <acas...@gmail.com> wrote: > > > > > 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 > > > > >> > > > > > > > > > > > > > > >
