Diff for /wikisrc/ports/evbarm/raspberry_pi.mdwn between versions 1.1 and 1.101

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 [[!meta title="NetBSD/evbarm on Raspberry Pi"]]  [[!meta title="NetBSD/evbarm on Raspberry Pi"]]
 This page attempts to document and coordinate efforts towards NetBSD/evbarm on [Raspberry Pi](http://www.raspberrypi.org).  This page attempts to document and coordinate efforts towards NetBSD/evbarm on [Raspberry Pi](http://www.raspberrypi.org). All board variants are supported.
 # What works  Initial, limited, Raspberry Pi support was introduced in NetBSD 6.0. NetBSD 7.0 adds complete support for the board, along with introducing support for the quad-core Raspberry Pi 2 board.  Raspberry Pi 3 support was added for NetBSD 8, and backported to NetBSD 7 in July of 2017.  (This page assumes those using NetBSD 7 are using 7.2, or the netbsd-7 branch after mid 2018.)
  - multi-user boot with root on SD card and serial console  
 # What needs work  [[images/raspberrypi.jpg]]
  - USB (host): work in progress  
  - I²C: work in progress  [[!toc levels=2]]
  - SPI: work in progress  
   <small>([Raspberry Pi image](http://www.flickr.com/photos/42325803@N07/8118758647/) by Christopher Lee used under CC-By-2.0 license)</small>
   # What works (and what doesn't yet)
   We use .e.g. "RPI2" to refer to "Raspberry Pi 2" to save precious bytes on this page.
   \todo Add information  on Pi Zero and Pi Zero W.
   ## NetBSD 7 and NetBSD 8
    - RPI1, RPI2, RPI3 (except RPI3 builtin WiFi and bluetooth)
    - RPI0 and RPI0W are expected to work (as RPI3, no WiFi, but one needs fdt files \todo where from?)
    - multiple processors on RPI2/RPI3
    - boots normally to multiuser, with FAT32 boot partition on uSD
    - root filesystem can be uSD or USB-attached mass storage
    - serial or graphics console (with EDID query / parsing)
    - X11 via HDMI
    - GPU (VCHIQ) - 3D and video decode. man page missing.
    - USB host controller - dwctwo(4) and most devices work
    - USB Ethernet - usmsc(4)
    - DMA controller driver and sdhc(4) support
    - RNG
    - Audio: works. man page missing.
  - GPIO   - GPIO
  - framebuffer   - I²C: works, could use enhancements, man page
  - almost everything relating to working with the VideoCore IV   - SPI: could use enhancements, man page
   ## NetBSD current
    - RPI3B+ 
    - RPI3 builtin bluetooth
    - RPI3 new SD host controller driver
   ## What needs work
    - USB (host); isochronous transfers.
    - RPI3 builtin WiFi
   # CPU types
    - RPI1 uses "earmv6hf".
    - RPI0 uses "\todo".
    - RPI2 uses "earmv7hf".
    - RPI3 uses "earmv7hf".
    - RPI0W uses "\todo".
   Note that one can run a build of earmv6hf on the 2 and 3.  There will still be a kernel7, built to use the 2/3 hardware, but with the armv6 instruction set.
   In theory the code compiled for earmv7hf will be faster, but anecdotal experience is that it doesn't matter that much.
   While the evbarm port has "eb" variants (for big-endian mode), the RPI systems do not support eb and these variants will not work.  Systems built with older CPU architectures (earm, earmv4, earmv5) are not expected to work on RPI.
   See also [[NetBSD/aarch64|aarch64]] for running the Pi 2/3 in 64-bit mode.
   # Installation
   ## SD card structure
   The Raspberry Pi looks for firmware and kernel.img on the first FAT32 MBR partition of the uSD card.  A separate kernel (kernel7.img) is used on RPI2 and RPI3.
   The NetBSD kernel will then find NetBSD MBR partition and within that the root disklabel partition, and use that FFS partition as the root filesystem.
   A 2 GB card is the smallest workable size, and the installation image will fit.  After the first boot, the system resizes the NetBSD root partition to fill the card.  Note that swap is after /boot and before /, and not contained in the NetBSD fdisk partition.  However, if you don't try to change the partition structure, this should not cause you any trouble.
   Note that SD cards generally have limited write tolerance, so you may wish to disable atime updates via the noatime option, as is done by the default installation.
   ## Choosing a version
   First, decide if you want to install a formal release (7.2 or 8.0), a stable branch build (netbsd-7, netbsd-8), or NetBSD-current.  For people who don't know how to choose among those, a recent build of netbsd-8 is probably best, with 8.0 the choice for those who value being at exactly a formal release.
   See also "ebijun's image", below, which is NetBSD-current and includes packages.
   ## Getting bits to install
   You can either build a release yourself with build.sh, or get a release from the NetBSD HTTPS/FTP servers.  The bits from both sources should match, except for things like  timestamps, or because the sources are from slightly different points along branches.
   ### Building yourself
   Getting sources and building a release with build.sh is not special for evbarm.  However, the evbarm port has a very large number of CPU types, compared to i386 and amd64 which have one each.  The standard approach is to use -m to define MACHINE and -a to define MACHINE_ARCH.  build.sh supports aliases that can be passed as a MACHINE value, but denote both MACHINE and a MACHINE_ARCH.   The third line uses an alias and is equal to the second, for RPI2/3.  Note that the aliases start with "evb" while the MACHINE_ARCH values do not, and that aliases have "-el" or "-eb", while the MACHINE_ARCH values have no suffix or "eb".
    - ./build.sh -m evbarm -a earmv6hf -u release
    - ./build.sh -m evbarm -a earmv7hf -u release
    - ./build.sh -m evbearmv7hf-el -u release
   Consider setting RELEASEMACHINEDIR if you wish to build multiple MACHINE_ARCH values for a MACHINE; see build.sh.  Use something like "evbarm-earmv7hf", so that 1) earvm6 and earmv7 don't collide and 2) anita will recognize it as a type of evbarm.
   ### NetBSD autobuild HTTPS/FTP servers
   NetBSD provides nightly builds on [nyftp.netbsd.org](https://nyftp.netbsd.org/pub/NetBSD-daily/).  The next directory level is the branch being built (netbsd-7, netbsd-8, HEAD, and more), plus optionally things like compiler type.  It is followed by date/time, e.g. "HEAD/201811051650Z"; once a build is complete the symlink "latest" is adjusted to point to it.  The next level is "${MACHINE}-${MACHINE_ARCH}", e.g. "evbarm-earmv7hf", and multiple combinations are provided.
   An example URL, arguably the standard approach for first-time NetBSD/RPI users, is https://nyftp.netbsd.org/pub/NetBSD-daily/netbsd-8/latest/evbarm-earmv7hf/binary/gzimg/
   ### release layout
   Once you get to the releasedir, self-built and autobuild releases have the same structure.
    - The 'evbarm-earmv6hf/binary/gzimg/' directory contains an rpi.img file that will run on any of the RPI boards.
    - The 'evbarm-earmv7hf/binary/gzimg/' directory contains an armv7.img file that uses the armv7 instruction set, and thus can run only on the Raspberry Pi 2/3.
   \todo Explain why there is no armv7_inst.gz.
   ## Preparing a uSD card
   Once you have rpi.img.gz (or rpi_inst), put it on a uSD card using gunzip and dd, for example:
    - gunzip rpi.img.gz
    - dd if=rpi.img of=/dev/disk1
   ## Console approaches
   The standard approach is to use a USB keyboard and an HDMI monitor for installation.
   ### Serial Console
   By default the rpi.img is set to use the HDMI output.  If you wish to use a serial console, mount the FAT32 partition on another system and edit cmdline.txt and remove '"console=fb"'.
    - Most (all?) USB-to-TTL serial adapters have wires for Tx, Rx and ground, and not RTS/CTS or other flow control lines.   Thus, your terminal program (or terminal) must be configured to not require flow control; a symptom of misconfiguration is that you see console output, but cannot type anything.  If so, adjust your serial console application's flow control settings to "none".
      - In Kermit, the command is "set flow none".
      - In minicom, run "minicom -s" and set hardware flow control to "no".
   ### Enabling ssh for installation without any console
   If you want to enable ssh with the standard image, so that you can log in over the net without either a serial or HDMI console, you can edit the configuration of a uSD card before booting.   On another computer, mount the ffs partition, place /root/.ssh/authorized_keys, uncomment PermitRootLogin in /etc/ssh/sshd_config, and comment out the rc_configure=NO in /etc/rc.conf.  Besides having to find the IP address (e.g. from DHCP server logs), you will have to wait for the partition resizing and reboot.
   ### Installation with sshramdisk image
   build.sh (and hence the FTP site) also creates an image 'rpi_inst.img.gz' specifically for installation without HDMI or a serial console, when built for earmv6hf.  Note that this image is much smaller and that you will need to fetch the sets over the network.  To use this method, write that image to a uSD card as above, and then:
    - Connect an Ethernet cable from the RPI to a LAN with a DHCP server, and another host you can use for ssh.
    - Power on the RPI, and wait.  Watch the logs on the DHCP server, and find the IP address assigned to the RPI.
    - Use ssh to login to the address you found with user "sysinst", and password "netbsd".
    - When installing, ensure that you enable DHCP and ssh, so that you can log in again after the system is installed.
   \todo Verify that the above is accurate and sufficient.
   ## Installation via ebijun's image
   As an alternative to the standard installation images, Jun Ebihara
   provides an install image for Raspberry Pi that includes packages.  It
   is based on NetBSD-current and is built for earmv6hf, and thus will
   work on Raspberry Pi 1, 2 and 3.  This image is typically updated
   every few weeks.
    - [https://github.com/ebijun/NetBSD/blob/master/RPI/RPIimage/Image/README](https://github.com/ebijun/NetBSD/blob/master/RPI/RPIimage/Image/README)
   ## Configuring 802.11
   After installation, the Ethernet will function as on any other NetBSD system; simply enable dhcpcd or configure a static address.  USB WiFi devices will also function as on any other NetBSD system; in addition to dhcpcd or static, configure and enable wpa_supplicant.
   Note that the built-in WiFi in the RPI3 is not yet supported.   USB WiFi interfaces (that work on NetBSD in general) should all work.  In particular, the following are known to work:
    - urtwn0: Realtek (0xbda) 802.11n WLAN Adapter (0x8176), rev 2.00/2.00, addr 5, MAC/BB RTL8188CUS, RF 6052 1T1R
   ## Links
   The following pages have been published by NetBSD community members.  (Note that some of them are old.)
    - https://www.cambus.net/netbsd-on-the-raspberry-pi/
   # Maintaining a system
   ## vcgencmd
   The program vcgencmd, referenced in the boot section,  can be found in pkgsrc/misc/raspberrypi-userland.
   ## Updating the kernel
    - Build a new kernel, e.g. using build.sh. It will tell you where the ELF version of the kernel is, e.g.
            Kernels built from RPI2:
    - Besides the "netbsd" kernel in ELF format, there is also a "netbsd.img" (for current) or "netbsd.bin" (for 7 and 8) kernel that is in a format that the Raspberry can boot.
    - Depending on your hardware version, copy this either to /boot/kernel.img (First generation Pi, Pi Zero hardware) or to /boot/kernel7.img (Pi 2, Pi 3 hardware)
    - reboot
   ## Updating the firmware
   A section below describes the process of updating NetBSD's copy of the firmware from upstream, with testing, by NetBSD developers.  This section is about updating a system's firmware from the firmware in a version of NetBSD.
   \todo Explain where the firmware is in the source tree, and if it is in the installed system image (such as /usr/mdec).  Explain how to update a system (presumably /boot) from either an installed system's new firmware files, or the source tree.  Explain any particular cautions.
   Probably, for the RPI3B+, one needs to use -current, or use -8 with firmware from -current.  \todo Defuzz.
   \todo Explain if using updated firmware from one branch (e.g. netbsd-current) on a system using a different branch (e.g. netbsd-8) is safe.  Explain if pullups are done to release branches with new firmware.
   ## Booting
   The device boots by finding a file "bootcode.bin".   The primary location is a FAT32 partition on the uSD card, and an additional location is on a USB drive.  See the [upstream documentation on booting](https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/) and read all the subpages.
   The standard approach is to use a uSD card, with a fdisk partition table containing a FAT32 partition marked active, and a NetBSD partition.  The NetBSD partition will then contain a disklabel, pointing to an FFS partition (a), a swap paritiion (b) and the FAT32 boot partition mounted as /boot (e).  The file /boot/cmdline.txt has a line to set the root partition.
   One wrinkle in the standard approach is that the disk layout is "boot swap /", but the NetBSD fdisk partition starts at the location of /.   The / partition can hold a disklabel, while swap cannot.   It is normal to have swap after / (and thus within the fdisk partition), but the arrangement used permits growing / on first boot, for the typical case where a larger uSD is used, compared to the minimum image size.
   An alternate approach is to have the boot FAT32 partition as above, but to have the entire system including root on an external disk.  This is configured by changing root=ld0a to root=sd0a or root=dk0 (depending on disklabel/GPT).  Besides greater space, part of the point is to avoid writing to the uSD card.
   A third approach, workable on the Pi 3 only, is to configure USB host booting (already enableed on the 3+; see the upstream documentation) and have the boot partition also on the external device.  In this case the external device must have an MBR because the hardware's first-stage boot does not have GPT support. In theory the [procedure to program USB host boot mode](https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md) will function on a NetBSD system because the programming is done by bootcode.bin.
   \todo Confirm that putting program_usb_boot_mode=1 in config.txt and booting works to program the OTP bit.  Confirm that one can then boot NetBSD from external USB.
   There is no well-defined USB enumeration order, so the preferred approach if one has multiple USB mass storage devices is to use named wedges in both fstab and cmdline.txt.
   # X11 and GPU
   ## Video playback
   Accelerated video playback is supported in NetBSD 7 with the [OMXPlayer](http://pkgsrc.se/multimedia/omxplayer) application and through GStreamer with the [omx](http://pkgsrc.se/multimedia/gst-plugins1-omx) plugin.
   ## OpenGL ES
   Accelerated OpenGL ES is supported in NetBSD 7. The GL ES client libraries are included with the [misc/raspberrypi-userland](http://pkgsrc.se/misc/raspberrypi-userland) package.
   ## Quake 3
   A Raspberry Pi optimized build of *ioquake3* is available in the [games/ioquake3-raspberrypi](http://pkgsrc.se/games/ioquake3-raspberrypi) package. To use it, the following additional resources are required:
    - pak0.pk3 from Quake 3 CD
    - additional pak files from the [games/ioquake3-pk3](http://pkgsrc.se/games/ioquake3-pk3) package
    - read/write permissions on /dev/vchiq and /dev/wsmouse
   Place the pak0.pk3 file in the /usr/pkg/lib/ioquake3/baseq3 directory.
   ## RetroArch / Libretro
   Using [emulators/retroarch](http://pkgsrc.se/emulators/retroarch) it is possible to run many emulators at full speed the Raspberry Pi. Emulator cores for various gaming consoles are available in the [emulators/libretro-*](http://pkgsrc.se/search.php?so=libretro-) packages. To begin using retroarch:
    - Install [emulators/retroarch](http://pkgsrc.se/emulators/retroarch)
    - Install the libretro core for the system you would like to emulate (lets take [emulators/libretro-gambatte](http://pkgsrc.se/emulators/libretro-gambatte), a GameBoy Color emulator, as an example).
    - Plug in a USB HID compatible Gamepad, such as the Logitech F710 in "DirectInput" mode (set "D/X" switch to "D").
    - Create a config file for your gamepad using *retroarch-joyconfig*.
   [[!template  id=programlisting text="""
   $ retroarch-joyconfig -o gamepad.cfg
    - Launch the emulator from the command-line (no X required):
   [[!template  id=programlisting text="""
   $ retroarch --appendconfig gamepad.cfg -L /usr/pkg/lib/libretro/gambatte_libretro.so game.gbc
   # Developer notes
   These notes are for people working on improvements to RPI support in NetBSD.
   ## Updating the firmware version in the NetBSD sources
   (Note that trying new firmware may result in a non-bootable system, so
   be prepared to recover the bootable media with another system.)
   Upstream firmware releases are
   [on GitHub](https://github.com/raspberrypi/firmware/releases).
   Copy all files except `kernel*.img` into `/boot` and reboot.
   New firmware should pass all of the following tests before being committed to NetBSD.
   - Audio
   - OMXPlayer (and [[!template id=man name="vchiq"]])
   - Serial/framebuffer console
   - CPU frequency scaling
   Tests should be run on all of `rpi[0123]`.
   ## Testing with anita and qemu
   anita has support for evbarm.  Install qemu and dtb-arm-vexpress from pkgsrc.  Note that the release subdirectory should be evbarm-earmv6hf or evbarm-earmv7hf.
   \todo Explain how to select various RPI models to emulate.
   \todo Explain about how DTB works.
   \todo Give a command line example to run qemu (without anita).

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