rk3399_rockchip-uboot/doc/README.distro

3  * Copyright (c) 2014-2015, NVIDIA CORPORATION.  All rights reserved.
6  * SPDX-License-Identifier:     GPL-2.0+
13 environments or bootloaders (PC BIOS, EFI, U-Boot, Barebox, ...). This makes
14 life complicated. Worse, bootloaders such as U-Boot have a configurable set
16 Hence, distros typically need to have board-specific knowledge in order to
19 This document defines a common set of U-Boot features that are required for
21 allow distros to install and boot in an out-of-the-box fashion should enable
24 to install on many boards without the need for board-specific logic.
33 board-specific installer/boot-configuration support in a distro.
36 that contains U-Boot, and that the user has somehow installed U-Boot to this
38 to this aspect of the model, the extent of the board-specific support in the
39 distro installer logic would be to install a board-specific U-Boot package to
40 the boot partition during installation. This distro-supplied U-Boot can still
42 configuration file generation logic can still be board-agnostic.
45 -----------------------
47 Typical desktop/server PCs search all (or a user-defined subset of) attached
49 configuration files from there. A U-Boot board port that enables the features
53 Thus, distros do not need to manipulate any kind of bootloader-specific
59 the MBR bootable flag, or GPT legacy_bios_bootable attribute), and U-Boot (or
65 U-Boot falls back to searching the first valid partition of a disk for boot
70 U-Boot can also search for boot configuration files from a TFTP server.
73 ------------------------
76 handled by U-Boot's "syslinux" (disk) or "pxe boot" (network). This is roughly
83 * Prescribes a separate configuration per boot menu option, whereas U-Boot
84   lumps all options into a single extlinux.conf file. Hence, U-Boot searches
93 ------------------------------------------------------------
105 default Fedora (3.17.0-0.rc4.git2.1.fc22.armv7hl+lpae) 22 (Rawhide)
107 label Fedora (3.17.0-0.rc4.git2.1.fc22.armv7hl) 22 (Rawhide)
108 	kernel /boot/vmlinuz-3.17.0-0.rc4.git2.1.fc22.armv7hl
109 …append ro root=UUID=8eac677f-8ea8-4270-8479-d5ddbb797450 console=ttyS0,115200n8 LANG=en_US.UTF-8 d…
110 	fdtdir /boot/dtb-3.17.0-0.rc4.git2.1.fc22.armv7hl
111 	initrd /boot/initramfs-3.17.0-0.rc4.git2.1.fc22.armv7hl.img
113 label Fedora (3.17.0-0.rc4.git2.1.fc22.armv7hl+lpae) 22 (Rawhide)
114 	kernel /boot/vmlinuz-3.17.0-0.rc4.git2.1.fc22.armv7hl+lpae
115 …append ro root=UUID=8eac677f-8ea8-4270-8479-d5ddbb797450 console=ttyS0,115200n8 LANG=en_US.UTF-8 d…
116 	fdtdir /boot/dtb-3.17.0-0.rc4.git2.1.fc22.armv7hl+lpae
117 	initrd /boot/initramfs-3.17.0-0.rc4.git2.1.fc22.armv7hl+lpae.img
119 label Fedora-0-rescue-8f6ba7b039524e0eb957d2c9203f04bc (0-rescue-8f6ba7b039524e0eb957d2c9203f04bc)
120 	kernel /boot/vmlinuz-0-rescue-8f6ba7b039524e0eb957d2c9203f04bc
121 	initrd /boot/initramfs-0-rescue-8f6ba7b039524e0eb957d2c9203f04bc.img
122 	append ro root=UUID=8eac677f-8ea8-4270-8479-d5ddbb797450 console=ttyS0,115200n8
123 	fdtdir /boot/dtb-3.16.0-0.rc6.git1.1.fc22.armv7hl+lpae
124 ------------------------------------------------------------
126 Another hand-crafted network boot configuration file is:
128 ------------------------------------------------------------
133 LABEL jetson-tk1-emmc
137 … console=tty1 loglevel=8 rootwait rw earlyprintk root=PARTUUID=80a5a8e9-c744-491a-93c1-4f4194fd690b
139 LABEL venice2-emmc
143 … console=tty1 loglevel=8 rootwait rw earlyprintk root=PARTUUID=5f71e06f-be08-48ed-b1ef-ee4800cc860f
149 … console=tty1 loglevel=8 rootwait rw earlyprintk root=PARTUUID=b2f82cda-2535-4779-b467-094a210fbae7
151 LABEL fedora-installer-fk
153         LINUX fedora-installer/vmlinuz
154         INITRD fedora-installer/initrd.img.orig
155         FDTDIR fedora-installer/dtb
157 ------------------------------------------------------------
159 U-Boot Implementation
163 ---------------------------
169 the Kconfig file in the root of the u-boot sources.
173 ------------------------------------------------------------
178 ------------------------------------------------------------
180 The first of those headers primarily enables a core set of U-Boot features,
182 raw zImage and initrd (rather than FIT- or uImage-wrapped files), etc. Network
185 media for non-PC targets at present.
187 Finally, a few options that are mostly relevant only when using U-Boot-
189 U-Boot-specific boot.scr script rather than extlinux.conf as the boot
192 allow for board-agnostic boot.scr content, this document recommends that
195 U-Boot. TODO: document the contract between U-Boot and boot.scr re: which
203 ------------------------------
205 The U-Boot "syslinux" and "pxe boot" commands require a number of environment
206 variables be set. Default values for these variables are often hard-coded into
207 CONFIG_EXTRA_ENV_SETTINGS in the board's U-Boot configuration file, so that
266 For suggestions on memory locations for ARM systems, you must follow the
267 guidelines specified in Documentation/arm/Booting in the Linux kernel tree.
270 MEM_LAYOUT_ENV_SETTINGS in include/configs/tegra124-common.h.
273 -------------------------
282 ------------------------------------------------------------
292 ------------------------------------------------------------
298 - Upper-case disk type (MMC, SATA, SCSI, IDE, USB, DHCP, PXE).
299 - Lower-case disk type (same options as above).
300 - ID of the specific disk (MMC only) or ignored for other types.
305 Once the user has installed U-Boot, it is expected that the environment will
316   Entries may be removed or re-ordered in this list to affect the boot order.
320   For disk-based booting, the list of directories within a partition that are
325   Entries may be removed or re-ordered in this list to affect the set of
330   The name of U-Boot style boot.scr files that $bootcmd searches for.
335   maintained for backwards-compatibility.)
337   Entries may be removed or re-ordered in this list to affect the set of
366 Interactively booting from a specific device at the u-boot prompt
369 For interactively booting from a user-selected device at the u-boot command
383  - run bootcmd_usb0
386  - run bootcmd_mmc1
389  - run bootcmd_pxe
394 - network targets
398 - storage targets (to which a device number must be appended)
407 way in future u-boot versions.  In particular the <device type>_boot