MINI:KernelPreviewTwo

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'Mini' Kernel Preview Two (aka MIKE p2)

Note: This kernel is now obsolete. MIKE p3 should be used instead.

MIKE p2 is the second public preview release of a Linux kernel for the Nintendo Wii video game console that can run under 'mini', the IOS firmware replacement from Team Twiizers.

This new release provides solutions to several of the issues mentioned in MIKE p1 and adds some enhancements.

Audience

This kernel release is targetted at people interested in Linux on the Nintendo Wii which have already installed Bootmii on their videoconsoles.

What's new in MIKE p2

Solved hardware I/O latency issues when using mini

Thanks to the recent discovery of the so called AHBPROT "feature" the kernel can now access all hardware directly (via memory mapped registers), bypassing the mini-proxy and reducing the CPU cycles wasted doing hardware input/output.

Additional RAM available

The kernel will now try to use as much MEM2 as possible when running under mini. In this case, about 11 additional megabytes of MEM2 RAM are made available as normal kernel memory to applications.

Builds for progressive scan video modes are now available

Using progressive scan in MIKE p1 was possible, but it required hex-editting the kernel image to change the argument. MIKE p2 has builds with this already done.

Downloads

You can find links to some pre-built binary images compatible with whiite-linux based distros (i.e. you can use one of these kernel images instead of the one that came originally with your whiite-linux system). Please, read the whiite-linux article to learn how to setup a barebones whiite-linux system, and the rest of this document to learn how to properly use the kernel images.

Environment Video mode Kernel image
mini 480i PAL (60Hz) mikep2-zImage-2.6.30.mini.480i_PAL60.elf
mini 576i PAL (50Hz) mikep2-zImage-2.6.30.mini.576i_PAL.elf
mini 480p PAL (60Hz) mikep2-zImage-2.6.30.mini.480p_PAL.elf
mini 480i NTSC (60Hz) mikep2-zImage-2.6.30.mini.480i_NTSC.elf
mini 480p NTSC (60Hz) mikep2-zImage-2.6.30.mini.480p_NTSC.elf
IOS auto mikep2-zImage-2.6.30.ios.elf

And, as always, the kernel patches are available for download via Sourceforge File Release System (FRS).

Hardware

Supported Hardware

The following hardware/peripherals are supported by the MIKE p2 kernel:

 "Classic" hardware
 - Non-accelerated 2D video hardware (VI)
   - Note: correct RGB framebuffer support requires our SDL library port
 - Audio hardware (AI,DSP)
 - EXI hardware (EXI)
   - (not compiled-in) Nintendo SD Card Adapter (DOL-019) or compatibles
   - (not compiled-in) Non-SDHC MMC/SD cards in SPI mode via a Nintendo DOL-019 or compatible
     adapter
   - Real Time Clock / SRAM
 - Serial Interface hardware (SI)
   - Nintendo GameCube controllers
   - Nintendo GameCube WaveBird wireless controllers
 "Native" hardware
 - MEM2 memory as normal RAM
 - SDHC and Non-SDHC SD cards in SD mode via the front SD card slot
 - Internal USB Bluetooth dongle
 - Nintendo Wii Remote (RVL-003) and related expansion accessories
 - Sensor bar
 - USB 1.x and 2.0 devices

Unsupported Hardware

The following hardware/peripherals are NOT yet supported:

 "Classic" hardware
 - Nintendo GameCube memory cards
 "Native" hardware
 - Internal wireless network card
 - Internal DVD drive

Dependencies

mini must have IPC_SDHC_EXIT support

MIKE won't work properly unless a version of 'mini' with IPC_SDHC_EXIT support is used. Nor the version of mini included in Bootmii beta1 nor the one bundled with Bootmii beta2 support the IPC_SDHC_EXIT call.

You can download a ready-to-use armboot.bin with IPC_SDHC_EXIT support or you can build one from sources using latest git from:

git://git.bootmii.org/mini

Make sure that you have copied mikep1-armboot.bin to /bootmii/armboot.bin within your SD card before attempting to use any of the mini-based MIKE kernel images.

Note that you don't need to upgrade armboot.bin if you already installed the one that came with MIKE p1.

Extra features of MIKE p2 when running under mini (vs IOS)

  • EHCI (USB 2.0) is supported
  • Increased I/O bandwidth for SDHC, USB 1.x and USB 2.0
  • Additional 11 MB of RAM are available

Notes when running MIKE p2 under mini

Root device name changes

The same MIKE p2 binary can run under mini and under IOS. However, if you plan to run MIKE p2 under IOS you need to make sure that the kernel command line is modified to reflect the proper root device, as the name is different in each case:

Environment Root Device
mini /dev/mmcblk0p2
IOS /dev/rvlsda2

kernel image may be only booted as /bootmii/ppcboot.elf

Due to SD card driver bugs in Bootmii menu it may be impossible to successfully boot MIKE using the SD card browser in Bootmii.

If your card is affected, the kernel won't get loaded and control will be returned to the Bootmii menu. If you have a USBGecko you can see the following error messages coming from Bootmii menu:

ENTRY APPS is a dir!
NEW SD PATH: '/APPS'
ENTRY MINI-L~1 is a dir!
NEW SD PATH: '/APPS/MINI-L~1'
ENTRY BOOT.ELF is a file! Trying to boot..
FILE: /APPS/MINI-L~1/BOOT.ELF
loading 2201273 bytesDMA timeout 00000000
sdmmc: MMC_READ_BLOCK_MULTIPLE failed for card 0 with 60

In this case, the only solution for now may be to copy the kernel image (mikep2-zImage-2.6.30.mini.*.elf) as /bootmii/ppcboot.elf and let mini launch the kernel directly when the console boots (mini doesn't suffer from the above mentioned SD card bugs) or when launched via the Boot Mii option in the Homebrew Channel.

The problem with this approach is that you cannot have both Bootmii menu and the MIKE kernel on the same SD card at the same time.

Video mode may need to be specified on the kernel command line

When mini boots the kernel (as ppcboot.elf) the video hardware isn't initialized, and thus, the kernel cannot guess the right video mode.

See the Graphics and Sound article on how to specify a video mode using the kernel command line, or use a pre-built kernel image that matches your video mode settings.

Hint: You can hexedit the kernel image and replace the existing kernel command line with your own. Look for the string "placeholder_for_additional_kernel_options_targetted_at_hexedit_lovers" within the kernel image.

OHCI (USB 1.x) may have issues

The OHCI controllers found on the Nintendo Wii video game consoles seem to have hardware bugs. The current OHCI driver adds two quirks to workaround the observed incorrect behaviours until now.

Issues will be addressed as they are detected.

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