From: Simona Toaca <[email protected]> Add instructions on how to use U-Boot to save DDR training data to NVM.
Signed-off-by: Simona Toaca <[email protected]> --- doc/board/nxp/index.rst | 1 + doc/board/nxp/qb.rst | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 34 insertions(+) create mode 100644 doc/board/nxp/qb.rst diff --git a/doc/board/nxp/index.rst b/doc/board/nxp/index.rst index 01d3468a47d..7e3e5e29880 100644 --- a/doc/board/nxp/index.rst +++ b/doc/board/nxp/index.rst @@ -29,3 +29,4 @@ NXP Semiconductors mx6ullevk rproc psb + qb diff --git a/doc/board/nxp/qb.rst b/doc/board/nxp/qb.rst new file mode 100644 index 00000000000..ba673ecff24 --- /dev/null +++ b/doc/board/nxp/qb.rst @@ -0,0 +1,33 @@ +.. SPDX-License-Identifier: GPL-2.0+ + Copyright 2026 NXP + +DDR QuickBoot flow +------------------ + +Some NXP boards (which use OEI - iMX943, iMX95) support saving DDR +training data to non-volatile memory, which is then available to OEI +at next cold reboot. OEI uses the saved data to run Quickboot flow and +avoid training the DDR again. This significantly reduces the boot time. + +There are 2 ways to save this data: + +1. automatically, in SPL (by enabling CONFIG_SPL_IMX_QB) + +- this will save the data on the current boot device (e.g. SD) +- other configs specific to the boot device need to be enabled (CONFIG_SPL_MMC_WRITE for saving to eMMC/SD) + +2. using qb command in U-Boot console (by enabling CONFIG_CMD_IMX_QB) + +- supports saving on the current boot device, or on another, specified device. +- if flashing via uuu, the command can be added in an uuu script (boot device needs to be specified) +- after save, the data in volatile memory is erased, so saving can happen only once per DDR training + +:: + + # To save/erase on current boot device + => qb save/erase + + # To save/erase on other boot device + => qb save/erase mmc 0 # eMMC + => qb save/erase mmc 1 # SD + => qb save/erase spi # NOR SPI -- 2.43.0
