u-boot/doc/README.iscsi

1 # iSCSI booting with U-Boot and iPXE
5 U-Boot has only a reduced set of supported network protocols. The focus for
34 An alternative to implementing these protocols in U-Boot is to use an existing
35 software that can run on top of U-Boot. iPXE[1] is the "swiss army knife" of
39 iPXE can be built as an EFI application (named snp.efi) which can be loaded and
40 run by U-Boot.
44 U-Boot loads the EFI application iPXE snp.efi using the bootefi command. This
46 U-Boot.
56 uses the ConnectController boot service of U-Boot to request U-Boot to connect a
57 file system driver. U-Boot reads from the iSCSI drive via the block IO protocol
59 protocol. Now iPXE can call the simple file protocol to load GRUB[2]. U-Boot
63 the EFI stub Linux is called as an EFI application::
65                   +--------+         +--------+
67                   | U-Boot |========>| iPXE   |
68                   | EFI    |         | snp.efi|
69     +--------+    |        | DHCP    |        |
74     +--------+    |        | Response|        |
77     +--------+    |        | HTTPS   |        |
82     +--------+    |        |         |        |
85     +--------+    |        | iSCSI   |        |
91     |        |<===|********|<========|        |       +--------+
97     |        |<===|********|<========|********|<======|        |      +--------+
101     +--------+    +--------+         +--------+       +--------+      |        |
109 but neither U-Boot nor iPXE does support this. So we should at least separate
117 For running iPXE on arm64 the bin-arm64-efi/snp.efi build target is needed::
121     make bin-arm64-efi/snp.efi -j6 EMBED=myscript.ipxe
131 iPXE by default will put the CPU to rest when waiting for input. U-Boot does
148     #define IMAGE_EFI               /* EFI image support */
154 ### Open-iSCSI
165 * [1](https://ipxe.org) https://ipxe.org - iPXE open source boot firmware
166 * [2](https://www.gnu.org/software/grub/) https://www.gnu.org/software/grub/ -
168 * [3](https://github.com/open-iscsi/open-iscsi/blob/master/README)
169      https://github.com/open-iscsi/open-iscsi/blob/master/README -
170      Open-iSCSI README