On Wed, Jan 19, 2022 at 12:39:03PM +0100, Heinrich Schuchardt wrote:
On 1/19/22 02:43, Simon Glass wrote:
Add documentation for this feature, including the commands and full devicetree bindings.
Signed-off-by: Simon Glass sjg@chromium.org
Changes in v3:
Update docs for "bootmeths" and "boot_targets" env vars
MAINTAINERS | 4 + doc/develop/bootstd.rst | 638 ++++++++++++++++++++++++++ doc/develop/distro.rst | 3 + doc/develop/index.rst | 1 + doc/device-tree-bindings/bootdev.txt | 18 + doc/device-tree-bindings/bootmeth.txt | 31 ++ doc/device-tree-bindings/bootstd.txt | 8 + doc/usage/bootdev.rst | 135 ++++++ doc/usage/bootflow.rst | 427 +++++++++++++++++ doc/usage/bootmeth.rst | 108 +++++ doc/usage/index.rst | 3 + 11 files changed, 1376 insertions(+) create mode 100644 doc/develop/bootstd.rst create mode 100644 doc/device-tree-bindings/bootmeth.txt create mode 100644 doc/usage/bootdev.rst create mode 100644 doc/usage/bootflow.rst create mode 100644 doc/usage/bootmeth.rst
diff --git a/MAINTAINERS b/MAINTAINERS index 8ad70d3d968..c2af8ada3c9 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -669,6 +669,10 @@ F: boot/bootmeth*.c F: boot/bootstd.c F: cmd/bootdev.c F: cmd/bootflow.c +F: doc/develop/bootstd.rst +F: doc/usage/bootdev.rst +F: doc/usage/bootflow.rst +F: doc/usage/bootmeth.rst F: drivers/mmc/mmc_bootdev.c F: include/bootdev.h F: include/bootflow.h diff --git a/doc/develop/bootstd.rst b/doc/develop/bootstd.rst new file mode 100644 index 00000000000..1b65a806efb --- /dev/null +++ b/doc/develop/bootstd.rst @@ -0,0 +1,638 @@ +.. SPDX-License-Identifier: GPL-2.0+:
+U-Boot Standard Boot +====================
+Introduction +------------
+Standard boot provides a built-in way for U-Boot to automatically boot +an Operating System without custom scripting and other customisation. It +introduces the following concepts:
- bootdev - a device which can hold or access a distro (e.g. MMC, Ethernet)
- bootmeth - a method to scan a bootdev to find bootflows (e.g. distro boot)
- bootflow - a description of how to boot (provided by the distro)
+For Linux, the distro (Linux distribution, e.g. Debian, Fedora) is responsible +for creating a bootflow for each kernel combination that it wants to offer.
This gets it completely wrong. There is one standardized boot flow: UEFI. All major distros support this. U-Boot has to offer UEFI booting out of the box.
I want to jump up and down and emphasize this part as well. While I believe our UEFI bootmgr is still missing the normal scan code, that's something that has been promised to be implemented. And that turns the bootcmd for platforms that just want to support modern off the shelf distros in to something fairly small.