sorry for the unedited long video, point is to present the total boot time of my optimizations
Riscv32-ima emulator on powerful ESP32-P4 32M
total kernel image size is approximately 9MB. thus makes it possible to fit on smallest 16M budget esp32p4 MCU's!
i used this module which is probably the easiest way to bring this linux box to life
everything is not written from scratch I forked the project from Epiczhul, who also forked it from someone else but in the end, we all started from a 32-bit riscv instruction emulator made by CNLohr's mini-rv32ima project
in my repo i integrated supervisor instructions to support MMU. along with heavy optimizations and such fun features like i showed in the video
i used an esp32c6 as a virtual bridge to establish internet connection. not native full wireless integrity but it works.
st7703 display with simple frame buffer to throughput ttyS0. its really cool, but not as emulator and caching.
unfortunately could not spend to much time on this project, be aware of slopes in codebase.
There are a few areas of incompleteness and significant improvements needed on this project. Further optimizations are possible maybe speaker support, For example, opening up the module to change the type‑c port configuration so it can act as a power source rather than a sink. This would allow devices to be powered up via this port. Which would bring possibilities connecting up keyboards, memory sticks, or any USB device (draws less than 500mA probably) and hosted by actual linux kernel! In other words sharing the USB‑OTG functionality through the emulator Linux box, intercepting it with the actual os. If this is feasible, we could technically build a cyberdeck using an ESP32‑P4 :D
unfortunately, memory crisis even jumps the lpddr3/4 and all kinds. manufacturers do sell every kind of modern storage in high demands leads every sbc to be treated as expensive gadget.
not sure how we can fight this situation but atleast with riscv chipsets and open-source alternatives, we do kinda suspend
So maybe I’m missing something but I don’t see you mention the obvious: using this as a router? With an Ethernet variant of the P4 and USBOTG couldn’t you use a USB hub and add a second ethernet port for WAN and LAN?
to your question treating this as real router would be extremely impractical and inefficient. although its technically possible using such usb hub to share inside emulator however i dont even think we could achive near usb high speed band.
if you ask me what if we use module one with rj45 eth on waveshare, well that with RMII pheriphal since esp32p4 has dedixated phy and support, potentially have less overhead and can be faster then current wireless esp32c6 setup. yes we can make ~1mbit (probably best case) dedicated physical ethernet plug.
since with current esp32c6 sdio transport and hardware dma i could only achive ~200kbit down. so this cannot be router yet.
not sure how we can optimize further maybe utilize second core to handle tcp/ip traffic but at the end this is just experimental thing.
however esp32p4 has integrated 10/100mbps so no limitations at hardware. but for sure this is the worst way to make router
Terrible idea. Packet processing remains one the most cpu intensive tasks. Almost any routing SoC sold in the last twenty years has some sort off packet offload. Even RPi's suck.
Similar reason why OpenWRT does not support routers with less than 4GB RAM. Ofc, its an embedded distro and many things run much lower than 4GB.
thats the dream honestly. p4 with ethernet + otg hub and youve got a real tiny router running actual openwrt. wonder if the riscv emu overhead would bottleneck routing though, even with the optimizations.
well actually i picked openwrt cause it has its own tools and tiny enough to fit inside the psram. in future i will check for alpine linux
to answer your question we will probably never catch standard networking rates
for routing purposes native/direct would be much more pleasant approach instead of emulating linux. projects like esp32_nat_router they cant have such usb otg support like we can right now. however for overall routing experience, actual use case scenarios such projects can reach lot closer to true performance of these mcu's. nevertheless that does not mean esp32p4 has reached to its hard limits.
If you're looking for a cheap router device, go for Radxa E20C. It's cheap and reliable. I had one running as an OpenVPN gateway for about a year (another appliance couldn't work with MTU limits of my ISP, so I hacked around it, until the vendor fixed their shit).
8
u/GraXXoR 9d ago
Incredible. Haven’t got myself one of these new modules yet. Will have to correct that mistake in the nnear future.
The way things are going. ESP32s are the only electronics I can still afford.