Lup Yuen LEE ported NuttX to Pine64 Phone and he made the LCD and framebuffer driver with NuttX console and some touchscreen keyboard! You may be looking for something like that right? :-)
Lup documents everything very well on his blog :-) https://lupyuen.org/ -- CeDeROM, SQ7MHZ, http://www.tomek.cedro.info On Wed, Nov 5, 2025, 22:49 Matteo Golin <[email protected]> wrote: > Hi all, > > Despite a relatively small bug with transfer size limits, the RPi4B microSD > card support is basically done. This is largely in part to how simple it is > on NuttX to write a lower-half SDIO implementation and have things just > work, which is incredible :) > > I now (ambitiously) want to set my eyes on graphics. It turns out that > rendering with a framebuffer is actually quite easy, but very CPU > intensive. I'm going to need to figure out how to get at the GPU properly. > *My > question is: *is anyone familiar with examples on how to implement the > necessary "lower-half" for the NuttX graphics library? I.e. what > functions/drivers I would need to get written to allow the basic windowing > display manager & LVGL to work on the HDMI outputs of the Pi? I have > briefly read the docs about the window manager and saw that there is a > framebuffer char driver that can be implemented, but I'm not sure how well > that scales to decent graphics. I suppose this is relatively uncharted > territory on an RTOS designed mainly with LCDs in mind as the only graphics > (?). If anyone has implemented graphics support for a device before and can > let me know a few source files to look at, that would be great! > > My main goal is essentially to get decently fast graphics going, since once > that's done and some USB HID device support is set up, I can port DOOM to > NuttX :) > > Thanks, > Matteo > > On Wed, Oct 22, 2025 at 12:32 PM Matteo Golin <[email protected]> > wrote: > > > Thanks Tomek! That would be a good resource. > > > > On Wed, Oct 22, 2025 at 7:29 AM Tomek CEDRO <[email protected]> wrote: > > > >> OpenBSD 7.8 has been just released and it has official support for rPI > >> 5 with all sorts of peripherals.. maybe this is the new source to look > >> for drivers code? :-) > >> > >> https://ftp.openbsd.org/pub/OpenBSD/7.8/arm64/INSTALL.arm64 > >> > >> https://cvsweb.openbsd.org/src/ > >> > >> Have a good day :-) > >> Tomek > >> > >> On Tue, Sep 16, 2025 at 5:22 PM Matteo Golin <[email protected]> > >> wrote: > >> > > >> > 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 <[email protected]> > 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 < > [email protected] > >> > > >> > > 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 <[email protected]> > >> 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 < > >> [email protected]> > >> > > > > 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 < > >> [email protected]> > >> > > > > 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 < > [email protected]> > >> > > wrote: > >> > > > > > > > >> > > > > > >> Sure! Public now :-) > >> > > > > > >> Tomek > >> > > > > > >> > >> > > > > > >> On Mon, Sep 1, 2025 at 9:24 PM Matteo Golin < > >> > > [email protected] > >> > > > > > >> > > > > > >> 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 < > >> [email protected]> > >> > > > > wrote: > >> > > > > > >> > > >> > > > > > >> > > Thank you Linguini, good luck and have fun! :-) > >> > > > > > >> > > Tomek > >> > > > > > >> > > > >> > > > > > >> > > On Mon, Sep 1, 2025 at 8:48 PM Matteo Golin < > >> > > > > [email protected] > >> > > > > > > > >> > > > > > >> > > 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 < > >> > > > > > >> [email protected]> > >> > > > > > >> > > 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 < > >> > > > [email protected]> > >> > > > > > >> 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 < > >> > > > > > >> > > [email protected]> > >> > > > > > >> > > > >> 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 > >> > > > > > >> > > > >> > > [email protected] 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 < > >> > > > > > >> [email protected]> > >> > > > > > >> > > 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 > < > >> > > > > > >> > > [email protected]> > >> > > > > > >> > > > >> 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 < > >> > > > > > >> [email protected]> > >> > > > > > >> > > > >> wrote: > >> > > > > > >> > > > >> > >>> > >> > > > > > >> > > > >> > >>>> On Tue, Aug 26, 2025 at 10:05 PM Matteo > >> Golin < > >> > > > > > >> > > > >> [email protected]> > >> > > > > > >> > > > >> > >>>> 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 > >> > > > > > >> > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > >> > >> > >> -- > >> CeDeROM, SQ7MHZ, http://www.tomek.cedro.info > >> > > >
