File:  [NetBSD Developer Wiki] / wikisrc / ports / evbarm / raspberry_pi.mdwn
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Tue Nov 6 03:13:59 2018 UTC (2 years, 10 months ago) by gdt
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raspberry_pi: explain SD card structure better

    1: [[!meta title="NetBSD/evbarm on Raspberry Pi"]]
    3: This page attempts to document and coordinate efforts towards NetBSD/evbarm on [Raspberry Pi]( All board variants are supported.
    5: 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.)
    7: [[images/raspberrypi.jpg]]
    9: [[!toc levels=2]]
   11: <small>([Raspberry Pi image]( by Christopher Lee used under CC-By-2.0 license)</small>
   13: # What works (and what doesn't yet)
   15: ## NetBSD 7 and NetBSD 8
   17:  - RaspberryPi 1, 2, 3 (except Pi 3 builtin WiFi and bluetooth)
   18:  - multiple processors on 2/3
   19:  - boots normally to multiuser, with FAT32 boot partition on uSD
   20:  - root filesystem can be uSD or USB-attached mass storage
   21:  - serial or graphics console (with EDID query / parsing)
   22:  - X11 via HDMI
   23:  - GPU (VCHIQ) - 3D and video decode. man page missing.
   24:  - USB host controller - dwctwo(4) and most devices work
   25:  - USB Ethernet - usmsc(4)
   26:  - DMA controller driver and sdhc(4) support
   27:  - RNG
   28:  - Audio: works. man page missing.
   29:  - GPIO
   30:  - I²C: works, could use enhancements, man page
   31:  - SPI: could use enhancements, man page
   33: ## NetBSD current
   35:  - Raspberry Pi 3 builtin bluetooth
   36:  - Raspberry Pi 3 new SD host controller driver
   38: ## What needs work
   40:  - USB (host); isochronous transfers.
   41:  - Raspberry Pi 3 builtin WiFi
   43: # CPU types
   45:  - Raspberry Pi 1 uses "earmv6hf".
   46:  - Raspberry Pi 0 uses "\todo".
   47:  - Raspberry Pi 2 uses "earmv7hf".
   48:  - Raspberry Pi 3 uses "earmv7hf".
   49:  - Raspberry Pi 0W uses "\todo".
   51: Note that one can run earmv6hf code on the 2 and 3.  See also
   52: [[NetBSD/aarch64|aarch64]] for running the Pi 2/3 in 64-bit mode.
   54: # Installation
   56: ## SD card structure
   58: 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.
   59: 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.
   61: 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.
   63: ## Choosing a version
   65: 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, 8.0 or netbsd-8 is probably best.
   67: See also "ebijun's image", below, which is NetBSD-current and includes packages.
   69: ## Getting bits to install
   71: You can either build a release yourself with, or get one from the NetBSD FTP servers.
   73: Both will provide rpi.img.gz and rpi_inst.img.gz.  Each is an image to be written to a uSD card, and has a FAT32 partition for booting.  In rpi.img.gz, there is also an FFS partition for NetBSD.
   75: ### Building yourself
   77: Getting sources and building a release with 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.  The standard approach is to use -m to define MACHINE and -a to define MACHINE_ARCH. 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 in effect, for RPI2/3.
   79:  - ./ -m evbarm -a earmv6hf -u release
   80:  - ./ -m evbarm -a earmv7hf -u release
   81:  - ./ -m earmv7hf-el -u release
   83: Consider setting RELEASEMACHINEDIR if you wish to build multiple MACHINE_ARCH values on the same system; see
   85: ### NetBSD autobuild HTTPS/FTP servers
   87: NetBSD provides nightly builds on [](  These are equivalent to building yourself.  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.
   89:  - The 'evbarm-earmv6hf/binary/gzimg/' directory contains an rpi.img file that will run on any of the RPI boards.
   90:  - 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, but is also faster than rpi.img.
   92: An example URL, arguably the standard approach for beginners, is
   94: ## Preparing a uSD card
   96: Once you have rpi.img.gz (or rpi_inst), put it on a uSD card using gunzip and dd, for example:
   98:  - gunzip rpi.img.gz
   99:  - dd if=rpi.img of=/dev/disk1
  101: ### Serial Console
  103: By default the rpi.img is set to use the HDMI output.  If you wish to use a serial console, first mount the FAT32 partition and then
  104: edit cmdline.txt and remove '"console=fb"'.
  106:  - Most (all?) USB-to-TTL serial adapters only connect Tx, Rx and ground, and do not connect any flow control lines. An effect of missing flow control is that you see console output, but cannot type anything. If so, adjust your serial console application's flow control settings to "none".
  108:    In Kermit, the command is "set flow none".
  110:    In minicom, run "minicom -s" and set hardware flow control to "no"
  112: ### Enabling ssh
  114: 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, 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, you will have to wait for the partition resizing and reboot.
  116: ### Installation with sshramdisk image
  118: (and hence the FTP site) also creates an image 'rpi_inst.img.gz' specifically for installation without HDMI or a serial console.  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:
  120:  - Ensure that you have a lan with a DHCP server.
  121:  - Connect an Ethernet cable from the RPI to the LAN.
  122:  - After starting DHCP client, SSH login to with user "sysinst", and password "netbsd".
  123:    - Be careful to note the ip address given during DHCP so you don't lose your connection
  124:    - Also for after the sysinst is done and the system reboots
  125:  - sysinst started!
  127: ## Installation via ebijun's image
  129: As an alternative to the standard installation images, Jun Ebihara
  130: provides an install image for Raspberry Pi that includes packages.  It
  131: is based on NetBSD-current and is built for earmv6hf, and thus will
  132: work on Raspberry Pi 1, 2 and 3.  This image is typically updated
  133: every few weeks.
  135:  - [](
  137: # Maintaining a system
  139: ## vcgencmd
  141: The program vcgencmd, referenced in the boot section,  can be found in pkgsrc/misc/raspberrypi-userland.
  143: ## Updating the kernel
  145:  - Build a new kernel, e.g. using It will tell you where the ELF version of the kernel is, e.g.
  147:          ...
  148:          Kernels built from RPI2:
  149:           /Users/feyrer/work/NetBSD/cvs/src-current/obj.evbarm-Darwin-XXX/sys/arch/evbarm/compile/RPI2/netbsd
  150:          ...
  152:  - 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.
  153:  - 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)
  154:  - reboot
  156: ## Updating the firmware
  158: 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.
  160: TODO: Explain where the firmware is in the source tree, and if it is in the installed system image (such as /usr/mdec).  Explain any particular cautions.
  162: ## Booting
  164: 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]( and read all the subpages.
  166: 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.
  168: 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.
  170: 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.
  172: 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]( will function on a NetBSD system because the programming is done by bootcode.bin.
  173: \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.
  175: \todo Explain USB enumeration and how to ensure that the correct boot and root devices are found if one has e.g. a small SSD for the system and a big disk.
  177: # Wireless Networking
  179: 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.
  181:  - A Realtek 802.11n USB adaptor configures as urtwn(4).
  182:    - Configure with wpa_supplicant in /etc/rc.conf -
  184:            ifconfig_urtwn0=dhcp
  185:            dhcpcd=YES
  186:            dhcpcd_flags="-q -b"
  187:            wpa_supplicant=YES
  188:            wpa_supplicant_flags="-B -i urtwn0 -c /etc/wpa_supplicant.conf"
  189:    - A sample wpa_supplicant.conf can be found at /usr/share/examples/wpa_supplicant/wpa_supplicant.conf
  191: # GPU
  193: ## Video playback
  194: Accelerated video playback is supported in NetBSD 7 with the [OMXPlayer]( application and through GStreamer with the [omx]( plugin.
  196: ## OpenGL ES
  197: Accelerated OpenGL ES is supported in NetBSD 7. The GL ES client libraries are included with the [misc/raspberrypi-userland]( package.
  199: ## Quake 3
  200: A Raspberry Pi optimized build of *ioquake3* is available in the [games/ioquake3-raspberrypi]( package. To use it, the following additional resources are required:
  202:  - pak0.pk3 from Quake 3 CD
  203:  - additional pak files from the [games/ioquake3-pk3]( package
  204:  - read/write permissions on /dev/vchiq and /dev/wsmouse
  206: Place the pak0.pk3 file in the /usr/pkg/lib/ioquake3/baseq3 directory.
  208: ## RetroArch / Libretro
  209: Using [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-*]( packages. To begin using retroarch:
  211:  - Install [emulators/retroarch](
  212:  - Install the libretro core for the system you would like to emulate (lets take [emulators/libretro-gambatte](, a GameBoy Color emulator, as an example).
  213:  - Plug in a USB HID compatible Gamepad, such as the Logitech F710 in "DirectInput" mode (set "D/X" switch to "D").
  214:  - Create a config file for your gamepad using *retroarch-joyconfig*.
  215: [[!template  id=programlisting text="""
  216: $ retroarch-joyconfig -o gamepad.cfg
  217: """]]
  218:  - Launch the emulator from the command-line (no X required):
  219: [[!template  id=programlisting text="""
  220: $ retroarch --appendconfig gamepad.cfg -L /usr/pkg/lib/libretro/ game.gbc
  221: """]]
  223: # Developer notes
  225: These notes are for people working on improvements to RPI support in NetBSD.
  227: ## Updating the firmware version in the NetBSD sources
  229: (Note that trying new firmware may result in a non-bootable system, so
  230: be prepared to recover the bootable media with another system.)
  232: Upstream firmware releases are
  233: [on GitHub](
  234: Copy all files except `kernel*.img` into `/boot` and reboot.
  236: New firmware should pass all of the following tests before being committed to NetBSD.
  238: - Audio
  239: - OMXPlayer (and [[!template id=man name="vchiq"]])
  240: - Serial/framebuffer console
  241: - CPU frequency scaling
  243: Tests shoudl be run on all of `rpi[0123]`.

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