rapuyama-linux

A Linux bring-up for the RapuYama hardware platform replacing Symbian at runtime.

This project takes over the phone from a running Symbian installation, hands control to an ARM Linux kernel, and brings up the RapuYama application SoC. It combines Symbian-side loaders and hardware probes, reverse engineering of Nokia's firmware, and experimental Linux drivers.

Current status: Linux runs Wayland and GLES 2 on the phone. The kernel boots the Broadcom VideoCore itself, powers the LCD panel up and drives it as a small KMS device: weston + foot run on the phone's own display, typed on the hardware keypad, with a working touchscreen. Userspace GLES 2 is rendered by the VideoCore's own GL server through libvcgl (a turning triangle at 170-250 fps, textures work). An interactive shell also runs over USB serial.

The former 240-second reset is fixed on the Nokia E6: Linux now services the secure PA_SWD watchdog. Kernel #196 completed four successful calls through 648 seconds on hardware (console log, fix and boot instructions). Enable it with e6.swd=1; it is currently opt-in.

This is a device-specific port, not a generic EKA2 compatibility layer. Some work may carry over to other phones using the same SoC, but each model still needs its own board description, memory and boot validation, and peripheral bring-up.

• Symbian takeover and probes - inspect memory mappings and peripheral registers, run small ARM payloads, and transfer control to Linux.
• Linux kernel port - an ARMv6 kernel configuration plus experimental RapuYama support for interrupt handling, timers, GPIO, clocks, watchdog, UART, and other peripherals.
• VideoCore display driver - boots the BCM2727B1 with Nokia's firmware (extracted from your own ROM dump), speaks VCHI to it, powers the panel up like Symbian and exposes a KMS device (/dev/dri/card0, /dev/fb0 with fbcon) for weston.
• GLES 2 on the VideoCore - /dev/vc-khrn in the display driver passes KHRN/DISP messages to the VideoCore's own GL server, linux/vc-khrn/libvcgl.so is the EGL 1.4 + GLES 2 client library for it.
• Input drivers - polled TC3589x keypad and maXTouch touchscreen drivers, keypad layout in linux/initramfs/xkb-e6.
• Secure watchdog bridge - services the PA_SWD watchdog from Linux so the phone no longer resets after 240 seconds.
• Symbian display-stack emulator - runs Nokia's display drivers from the ROM in Unicorn and records every message they send to the VideoCore; the Linux driver replays those sequences.
• RAM-backed early logging - preserve early kernel output in reserved RAM so it can be retrieved after a failed boot, even without a serial console.
• Hardware notes - reverse-engineering results from firmware analysis and live probes.

The basic boot, timer/IRQ path, initramfs userspace, USB serial shell, the VideoCore display with weston and GLES 2, keypad, touchscreen, MMC enumeration and the secure watchdog bridge have been exercised on the phone. Other devices and drivers remain experimental, their presence in the tree does not imply that they have been validated on hardware.

On a Linux host, install an ARM GNU EABI cross-toolchain (arm-linux-gnu-gcc and binutils), then initialize the kernel submodule and build:

git submodule update --init --depth 1 linux/kernel/linux
cd linux/kernel
./build-kernel.sh e6config
./build-kernel.sh build

The kernel image is written to:

linux/kernel/build/arch/arm/boot/zImage

The build script uses ARCH=arm, CROSS_COMPILE=arm-linux-gnu-, and all available CPU cores by default. e6config installs the checked-in E6 configuration, build builds the kernel image and the kernel tree's DTBs.

The board DTB used by the E6 loader comes from linux/boot/e6.dts. It is separate from the DTBs built by the kernel target above. After building the kernel (which also builds the in-tree dtc compiler), run this from the repository root:

linux/kernel/build/scripts/dtc/dtc -I dts -O dtb -o linux/boot/e6.dtb linux/boot/e6.dts

The resulting linux/boot/e6.dtb is the board description to pair with the kernel image. If you change the DTS, rebuild this file before deploying it.

Symbian
  |_ e6bfix.sis / e6calb.sis
       |_ allocates the biggest free physical block
       |_ loads E:\Image (uncompressed) at block + 0x8000, E:\e6.dtb at block + 0x1f00000
       |_ prepares the handoff (MMU and caches off)
       |_ jumps to the Linux ARM kernel
            |_ early log is captured in reserved RAM

The kernel runs in place where it was loaded: ARM_PATCH_PHYS_VIRT makes the block PHYS_OFFSET, Linux drops the RAM below it. e6calb.sis is the same loader, it also times the handoff right after a Symbian PA_SWD service and is the one to use with e6.swd=1. The older e6boot.sis (zImage, fixed decompression address) still exists but big kernels die at random boots with it.

The phone-side package and boot sequence are documented in linux/boot/README.md. That guide includes the expected files, recovery/diagnostic notes, and the distinction between normal and probe images. Do not mistake a diagnostic probe image for the regular kernel.

For the interactive USB shell, use the USB-enabled DTB as E:\e6.dtb, connect the phone to the host over USB, and start the boot package. On a Linux host, connect to the enumerated gadget serial port, typically:

picocom -b 115200 /dev/ttyACM0

The shell runs on the phone's ttyGS0. picocom provides the host-side terminal. The USB-enabled DTB opts into this shell, while the base DTB uses the non-interactive init path.

build-kernel.sh builds the plain USB-shell kernel. For the display, use build-vc.sh. It needs a dump of the phone's kernel ROM (kern.bin, see ROM analysis), because the VideoCore firmware is extracted from it at build time and is not part of this repository:

KERN_BIN=/path/to/kern.bin linux/kernel/build-vc.sh

Daily set: linux/kernel/build-vc/arch/arm/boot/Image + linux/kernel/build-vc/e6-vc-565.dtb (gfx DMA + RGB565) as E:\Image / E:\e6.dtb, booted with e6bfix.sis or e6calb.sis. The script also builds e6-vc.dtb (XRGB8888), e6-vc-khrn.dtb and e6-vc-gl.dtb (VideoCore GL checks). Add e6.swd=1 to the bootargs for runs longer than 240 seconds. Driver parameters, weston, GLES 2, the bring-up sequence and known issues are in docs/videocore-display.md.

GLES 2 userspace (libvcgl, khrntest, vctri) is built by linux/vc-khrn/build.sh against the alpine sysroot from linux/initramfs/sysroot.sh.

• Linux bring-up notes
• Kernel build guide
• Boot pipeline and phone-side instructions
• RapuYama driver reverse engineering
• Hardware memory map
• ROM analysis notes
• VideoCore display: overview and driver
• VideoCore link: wire-level notes
• Porting guide for other RapuYama / VideoCore phones

• This is an early userspace bring-up, not yet a complete everyday phone OS.
• Pushing pixels is slow: the ViSSI bus does ~7 MB/s, so weston (pixman) gets ~9-16 fps in RGB565 and the VideoCore ignores partial write rects. Fast UI has to be rendered on the VideoCore (GLES 2). libvcgl has one config (RGB565, no depth/stencil), one buffer per window and no VC-to-host bulk transfers yet (no glReadPixels, info logs). Blanking/backlight control are not implemented. The display comes up a few seconds into boot, so use the USB shell or the RAM log for early messages.
• Storage is read-only for now: the SD card retry fix is not validated on hardware, and the internal eMMC is Symbian's E: drive - never write to it.
• The PA_SWD bridge is opt-in (e6.swd=1) and validated only with the E6 firmware context and the e6calb loader. Modem, radio, audio and power key are not supported.
• Treat register addresses and undocumented peripheral behavior as hypotheses unless the notes explicitly say they were checked on live hardware.
• A successful boot does not imply that every peripheral or power-management path is implemented.
• The boot handoff is one-way. A failed run may require the phone's watchdog reset to recover.