The mcimx6ul-evk machine can boot Linux directly, but it cannot run the U-Boot proper produced by Buildroot far enough to load a kernel from its SD card. Early U-Boot boot test accesses currently abort or observe placeholder values, and the i.MX uSDHC model exposes several issues.
This series lets an unmodified Buildroot 2026.05 U-Boot 2024.07 image run on mcimx6ul-evk, load zImage and imx6ul-14x14-evk.dtb from USDHC2, start Linux, mount the SD card root file system, and reach the Buildroot login prompt. It also documents and tests the existing direct Linux boot path. Patches 1 through 4 provide the minimum early-firmware-visible state. Patches 5 through 8 address i.MX uSDHC behavior needed by U-Boot. The last two patches document both boot paths and add functional tests for U-Boot and direct Linux boot. This series is based on: <[email protected]> as the sdhci changes have conflicts. Changes in v3: - Rebase on the v3 PolarFire SoC Icicle Kit series - Model the full reserved page as a child of a15mpcore_priv - Validate MMDC RAM geometry and document supported capacities - Translate uSDHC vendor clock gates in its MMIO handlers - Cover partial reset accesses and migrate vendor clock state - Extend contiguous SDMA completion to both eSDHC byte orders Bin Meng (10): hw/cpu: a15mpcore: Model the reserved page as RAZ/WI hw/misc: imx6ul_ccm: Update PMU_MISC0 reset value hw/arm: fsl-imx6ul: Map early firmware register placeholders hw/arm: fsl-imx6ul: Add a minimal MMDC geometry model hw/sd: sdhci: Use a QEMU-local no-busy IRQ quirk bit hw/sd: sdhci: Honor i.MX uSDHC vendor clock gates hw/sd: sdhci: Preserve uSDHC status enables for U-Boot hw/sd: sdhci: Skip SDMA boundary stops for eSDHC and uSDHC docs/system/arm: Document MCIMX6UL-EVK Buildroot boot tests/functional/arm: Add MCIMX6UL-EVK boot tests MAINTAINERS | 1 + docs/system/arm/mcimx6ul-evk.rst | 72 +++++++++++ include/hw/arm/fsl-imx6ul.h | 2 + include/hw/cpu/a15mpcore.h | 6 + include/hw/sd/sdhci.h | 10 +- hw/arm/fsl-imx6ul.c | 87 ++++++++++++- hw/arm/mcimx6ul-evk.c | 2 + hw/cpu/a15mpcore.c | 53 ++++++++ hw/misc/imx6ul_ccm.c | 2 +- hw/sd/sdhci.c | 151 +++++++++++++++++----- tests/functional/arm/meson.build | 2 + tests/functional/arm/test_mcimx6ul_evk.py | 69 ++++++++++ 12 files changed, 416 insertions(+), 41 deletions(-) create mode 100644 tests/functional/arm/test_mcimx6ul_evk.py --- base-commit: 3ee3bacb1edd0896cb26f0f66493b4ab006fbffa branch: imx6ul-evk -- 2.53.0
