sunxi64: a64-olinuxino u-boot — build eMMC device tree (fix eMMC boot)

[igorpecovnik]

Problem

On the Olimex A64-OLinuXino (eMMC), eMMC installs don't boot after the sunxi64 u-boot bump v2024.01 → v2026.07 (aea0a3c24). Serial shows full u-boot loading fine, then failing to initialize the eMMC:

=> ls mmc 2:1
Card did not respond to voltage select! : -110
** Bad device specification mmc 2 **

u-boot can't read the eMMC → no boot.scr → falls through to USB/network. The eMMC hardware and the install are fine (Linux mounts mmcblk2 normally; BROM/SPL still load u-boot from it) — only full u-boot can't bring the eMMC up.

Root cause

The bump started a fresh v2026.07-sunxi64 patchdir and, per its commit message, only re-added a listed set of board patches. board_lime-a64 was dropped. Its add-a64-olinuxino-emmc-support.patch injected the &mmc2 eMMC node into the DT. Without it, a64-olinuxino_defconfig builds the base sun50i-a64-olinuxino DT, which has no eMMC node → u-boot has nothing to init.

Fix

Point the defconfig at upstream's ready-made sun50i-a64-olinuxino-emmc DT instead of re-carrying the old patch. It's more complete than the dropped patch — it adds vqmmc-supply = <&reg_eldo1> (the 1.8 V I/O rail the "voltage select" step needs) on top of vmmc, 8-bit bus, non-removable, cap-mmc-hw-reset. CONFIG_MMC_SUNXI_SLOT_EXTRA=2 is already set.

-CONFIG_DEFAULT_DEVICE_TREE="sun50i-a64-olinuxino"
+CONFIG_DEFAULT_DEVICE_TREE="sun50i-a64-olinuxino-emmc"

Validation

• Patch applies clean to u-boot v2026.07; the -emmc DTS is present upstream and includes the base DT + the mmc2 node.
• Hardware test pending: rebuild u-boot for lime-a64 and reflash — the eMMC should init and boot standalone.

Note

The same board dir's add-a64-olinuxino-spl-spi.patch (SPL SPI-flash boot) was also dropped in the bump — separate feature, not restored here.

Summary by CodeRabbit

• Bug Fixes
  • Updated the default hardware configuration for A64 OLinuXino boards to use the eMMC-specific device tree.
  • Improved device detection and initialization for systems using onboard eMMC storage.
  • Preserved support for the additional MMC slot.

[coderabbitai]

📝 Walkthrough

Walkthrough

The patch documents the required eMMC device-tree configuration and changes the A64 Olinuxino U-Boot default device tree to sun50i-a64-olinux-emmc.

Changes

A64 Olinuxino eMMC configuration

Layer / File(s)	Summary
Select the eMMC device tree patch/u-boot/v2026.07-sunxi64/board_lime-a64/a64-olinuxino-build-emmc-devicetree.patch	The patch documents the missing eMMC node and changes CONFIG_DEFAULT_DEVICE_TREE to sun50i-a64-olinux-emmc. The existing extra MMC slot setting remains unchanged.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• armbian/build#9989: Both changes update U-Boot device-tree configuration for onboard eMMC on different boards.
• armbian/build#10089: Extends the sunxi64 U-Boot migration with the Lime A64 eMMC device-tree selection.

Suggested reviewers: deece, johnthecoolingfan, pyavitz, schwar3kat

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly identifies the A64-OLinuXino U-Boot change and its purpose of fixing eMMC boot.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/a64-olinuxino-uboot-emmc-dt

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In
`@patch/u-boot/v2026.07-sunxi64/board_lime-a64/a64-olinuxino-build-emmc-devicetree.patch`:
- Line 2: Correct the patch header date weekday from “Wed” to “Thu” while
leaving the date, time, and all other patch metadata unchanged.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

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Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 5fa3643e-079f-477c-aa63-88f79df61a2f

📥 Commits

Reviewing files that changed from the base of the PR and between e27ccd2 and 310e7ef.

📒 Files selected for processing (1)

• patch/u-boot/v2026.07-sunxi64/board_lime-a64/a64-olinuxino-build-emmc-devicetree.patch

[igorpecovnik]

Hardware-confirmed on the Olimex A64-OLinuXino (eMMC): with the patched u-boot built and a fresh armbian-install to eMMC, the board boots standalone from eMMC. Pointing the defconfig at upstream sun50i-a64-olinuxino-emmc (with vqmmc-supply = <&reg_eldo1>) resolves the Card did not respond to voltage select! : -110 eMMC init failure introduced when the v2024.01→v2026.07 bump dropped the board_lime-a64 eMMC DT patch.