u-boot/configs/tools-only_defconfig
Kory Maincent 2f84e9cf06 cmd: add support for a new "extension" command
This patch adds a new "extension" command, which aims at detecting
extension boards connected to the hardware platform, and apply the
Device Tree overlays that describe the hardware present on those
extension boards.

In order to enable this mechanism, board-specific code must implement
the extension_board_scan() function that fills in a linked list of
"struct extension", each describing one extension board. In addition,
the board-specific code must select the SUPPORT_EXTENSION_SCAN Kconfig
boolean.

Based on this:

 - "extension scan" makes the generic code call the board-specific
   extension_board_scan() function to retrieve the list of detected
   extension boards.

 - "extension list" allows to list the detected extension boards.

 - "extension apply <number>|all" allows to apply the Device Tree
   overlay(s) corresponding to one, or all, extension boards

The latter requires two environment variables to exist and set one variable
to run:

 - extension_overlay_addr: the RAM address where to load the Device
   Tree overlays

 - extension_overlay_cmd: the U-Boot command to load one overlay.
   Indeed, the location and mechanism to load DT overlays is very setup
   specific.

 - extension_overlay_name: set by the command: the name of the DT which
   will be load during the execution.

When calling the command described in the extension_overlay_cmd
variable, the variable extension_overlay_name will be defined. So a
typical extension_overlay_cmd will look like this:

  extension_overlay_cmd=load mmc 0:1 $extension_overlay_addr /boot/$extension_overlay_name

Here is an example on how to use it:
=> run loadfdt
=> fdt addr $fdtaddr
=> setenv extension_overlay_addr 0x1000
=> setenv extension_overlay_cmd 'load mmc 0:1 ${extension_overlay_addr} /boot/${extension_overlay_name}'
=> extension scan
Found 1 extension board(s).
=> extension apply 0
519 bytes read in 3 ms (168.9 KiB/s)

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Reviewed-by: Maxime Ripard <maxime@cerno.tech>
2021-05-13 13:09:05 -04:00

33 lines
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CONFIG_SYS_TEXT_BASE=0
CONFIG_ENV_SIZE=0x2000
CONFIG_DEFAULT_DEVICE_TREE="sandbox"
CONFIG_ANDROID_BOOT_IMAGE=y
CONFIG_FIT=y
CONFIG_FIT_SIGNATURE=y
CONFIG_MISC_INIT_F=y
# CONFIG_CMD_BOOTD is not set
# CONFIG_CMD_BOOTM is not set
# CONFIG_CMD_ELF is not set
# CONFIG_CMD_EXTENSION is not set
CONFIG_BOOTP_DNS2=y
# CONFIG_CMD_DATE is not set
CONFIG_OF_CONTROL=y
CONFIG_OF_HOSTFILE=y
CONFIG_SYS_RELOC_GD_ENV_ADDR=y
CONFIG_BOOTP_SEND_HOSTNAME=y
CONFIG_IP_DEFRAG=y
# CONFIG_ACPIGEN is not set
CONFIG_AXI=y
CONFIG_AXI_SANDBOX=y
# CONFIG_UDP_FUNCTION_FASTBOOT is not set
CONFIG_SANDBOX_GPIO=y
CONFIG_PCI=y
CONFIG_DM_PCI=y
CONFIG_PCI_SANDBOX=y
CONFIG_DM_RTC=y
CONFIG_SOUND=y
CONFIG_SYSRESET=y
# CONFIG_VIRTIO_MMIO is not set
# CONFIG_VIRTIO_PCI is not set
# CONFIG_VIRTIO_SANDBOX is not set
# CONFIG_EFI_LOADER is not set