Changes between Version 7 and Version 8 of venice/boot


Ignore:
Timestamp:
05/01/2023 09:43:02 PM (14 months ago)
Author:
Tim Harvey
Comment:

move U-Boot details to new page

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  • venice/boot

    v7 v8  
    7070
    7171The following items are supported in the Gateworks U-Boot for Venice:
    72  - eth0 (IMX8MM FEC GbE)
    73  - USB Host mode (USB Mass Storage and USB Networking for ASIX USB 2.0 USB Network device)
     72 - IMX8M FEC GbE
     73 - IMX8MP EQOS GbE
     74 - USB Host support (USB Mass Storage and USB Networking for ASIX USB 2.0 USB Network device)
    7475 - eMMC / microSD
    7576
    7677The following items are not currently supported in the Gateworks U-Boot for Venice:
    77 - PCIe support (include eth1 PCIe based Gbe)
    78 - USB device mode support (for USB OTG)
     78- PCIe support (include PCIe based Gbe)
    7979
    80 
    81 [=#distro-config]
    82 == Distro Config
    83 The Venice Bootloader uses U-Boot's 'Distro Config' which is a well defined U-Boot env intended to make it easier for distro maintainers to develop compatible bootscripts. This primarily entails a set of 'boot scripts' and variables that control them.
    84 
    85 Ultimately this U-Boot environment is looking for a U-Boot [#bootscript boot script] on a 'bootable' partition (partitions with the 'boot' flag enabled). It searches in this order with these rules:
    86  - **boot_targets** - list of target device type/nums to search: defaults to mmc1 mmc2 usb0 usb1 pxe
    87  - **devplist** - ''dynamically created'' list of all partitions flagged as 'bootable'
    88  - **boot_prefixes** - list of directories within a partition searched for bootscripts
    89  - **boot_scripts** - list of boot script names searched for
    90 
    91 
    92 [=#bootscript]
    93 == Boot Scripts
    94 When writing bootscripts compatible with [#distro-config Distro Config] you can assume the following env variables:
    95  - **devtype** - the device type the script was loaded from (mmc|usb|sata)
    96  - **devnum** - the device number the script was loaded from (ie 0 for mmc0, 1 for mmc1, etc)
    97  - **distro_bootpart** - the partition number the script was loaded from (ie 0, 1, etc)
    98  - **fdtcontroladdr** - the address the device-tree is at (Note that the Venice bootloader does not load/manipulate the device-tree itself - this is done by the SPL which loads/manipulates the device-tree and passes it to the bootloader)
    99  - **kernel_addr_r** - address where kernel can be loaded
    100  - **bootargs** - default bootargs to pass to the kernel - you probably want to add to this and not overwrite it
    101  - **console** - the serial console device to pass to the kernel
    102 
    103 Additionally you should note the following:
    104  - use load/ls/save commands which support FAT/ext filesystem types automatically instead of the fs specific commands
    105  - if using a root filesystem that is not supported by the bootloader (ie F2FS or BTRFS) you can place your bootscript and kernel image in the FAT12 filesystem on partition 1 of the boot device. This filesystem is part of the 16MB 'Boot Firmware' image. If doing so you will need to compress the kernel and package it into a [#fit FIT image] in order to fit it in the available space.
    106 
    107 The Distro-Config environment supports legacy uImage scripts (it does not support FIT images with scripts). You can create these with the {{{mkimage}}} tool from U-Boot as such:
    108 {{{#!bash
    109 mkimage -A arm64 -T script -C none -d boot.txt boot.scr
    110 }}}
    111 
    112 The bootscript can be updated at runtime on the Linux target. For example:
    113 {{{#!bash
    114 mkimage -A arm64 -T script -C none -d boot.txt /boot/boot.scr
    115 }}}
    116 
    117 
    118 [=#boot_targets]
    119 === Boot Device Order (boot_targets)
    120 While the Venice product family can only boot from its primary boot device (typically eMMC), once you are booted to the bootloader you can choose from a wider variety of devices to boot the OS from.
    121 
    122 This OS boot device order is specified by the [#distro-config Distro Config] environment. Specifically it is controlled by the {{{boot_targets}}} env variable which defaults to {{{mmc1 mmc2 usb0 usb1 pxe}}}.
    123 
    124 For example, to limit OS booting to only USB:
    125 {{{#!bash
    126 setenv boot_targets usb0 usb1
    127 saveenv
    128 }}}
    129 
    130 
    131 [=#fit]
    132 == Flattened Image Tree (FIT) images
    133 The U-Boot bootloader supports Flattened Image Tree (FIT) images which expand greatly on the legacy U-Boot image (uImage) format by allowing multiple binary blobs within an image. These blobs can be kernel images, ramdisk images, device-tree blobs, and bootloader scripts. Each image can also be optionally compressed (meaning U-Boot will decompress it) and check-sumed with a variety of hash mechanisms (meaning U-Boot will verify the image before using it).
    134 
    135 Quick summary of FIT Images:
    136  * introduced to resolve limitations with original single-image formats and follow-on multi-image format supported by UBoot bootm (boot memory)
    137  * uses power of the Device-Tree-Compiler (DTC)
    138  * FIT .itb files can be created with mkimage by passing in a .its file which in device-tree notation describes the images
    139  * U-Boot supports FIT with several commands:
    140   - {{{source <addr>:<name>}}} # source a script by name from FIT image in memory
    141   - {{{iminfo <fitaddress>}}} # print all the info contained in a FIT image in memory and verify (just not boot it)
    142   - {{{imextract <fitaddress> <item> <addr>}}} # extract item (ie kernel@1) to addr
    143   - {{{bootm <fitaddress>[#conf] - $fdtcontroladdr}}} # boot default or 'conf' configuration (ie #config@1)
    144   - {{{bootm start <fitaddress>[#conf] - $fdtcontroladdr}}} # boot from memory a specific configuration (or default configuration) from FIT image
    145 
    146 Example:
    147  * kernel.its with a single compressed kernel for ARM64
    148 {{{#!bash
    149 /dts-v1/;
    150 / {
    151         description = "Simple image with single Linux kernel";
    152         #address-cells = <1>;
    153         images {
    154                 kernel@1 {
    155                         description = "Linux kernel";
    156                         data = /incbin/("./Image.gz");
    157                         type = "kernel";
    158                         arch = "arm64";
    159                         os = "linux";
    160                         compression = "gzip";
    161                         load = <0x40200000>;
    162                         entry = <0x40200000>;
    163                         hash@1 {
    164                                 algo = "sha256";
    165                         };
    166                 };
    167         };
    168 
    169         configurations {
    170                 default = "conf@1";
    171                 conf@1 {
    172                         description = "Boot Linux kernel";
    173                         kernel = "kernel@1";
    174                 };
    175         };
    176 };
    177 }}}
    178  * create image:
    179 {{{#!bash
    180 cp arch/arm64/boot/Image .
    181 gzip Image
    182 mkimage -f kernel.its /tftpboot/kernel.itb
    183 }}}
    184  * boot the default configuration from U-Boot:
    185 {{{#!bash
    186 tftpboot $loadaddr kernel.itb && bootm $loadaddr - $fdtcontroladdr
    187 }}}
    188 
    189 References:
    190  * [http://git.denx.de/?p=u-boot.git;a=tree;f=doc/uImage.FIT doc/uImage.FIT]
    191  * http://www.denx.de/wiki/pub/U-Boot/Documentation/multi_image_booting_scenarios.pdf
    192  * http://elinux.org/images/f/f4/Elc2013_Fernandes.pdf
    193 
    194 
    195 = U-boot env tools
    196 A detailed description of u-boot-tools usage can be found [wiki:/ventana/bootloader#U-Bootenvtoolsfw_printenvfw_setenv here]. 
    197 
    198 In order to configure u-boot-tools to work correctly for Venice you will need a fw_env.config file the appropriate values. 
    199 
    200 To create this file:
    201 {{{#!bash
    202 cat << EOF > /etc/fw_env.config
    203 # Device               offset          Env. size
    204 /dev/mmcblk2           0xff0000        0x8000
    205 /dev/mmcblk2           0xff8000        0x8000
    206 EOF
    207 }}}
    208 
     80see [wiki:uboot] for more info