u-boot.git/arch/m68k/cpu, branch master

Merge patch series "m68k: Add support for QEMU virt machine"

2026-02-02T20:25:48+00:00

Kuan-Wei Chiu  says:

Add support for the QEMU 'virt' machine on the m68k architecture. The
QEMU virt machine models a generic system utilizing Goldfish virtual
peripherals and is capable of emulating various classic 68k CPUs.

Currently, U-Boot's m68k architecture support focuses on ColdFire
variants. This series expands support to include the classic M680x0
architecture, implementing the necessary exception vectors, startup
code, and a bootinfo parser compatible with the QEMU interface.

Drivers for Goldfish peripherals (TTY, Timer, RTC) and the QEMU
Virtual System Controller (sysreset) are also added to enable serial
console, timekeeping, and system reset functionality.

The implementation has been verified on QEMU targeting the M68040 CPU,
confirming successful hardware initialization and boot to the U-Boot
command shell. Additionally, the CI configuration was verified locally
using gitlab-ci-local "qemu_m68k_virt test.py", resulting in
PASS qemu_m68k_virt test.py.

Link: https://lore.kernel.org/r/20260107201838.3448806-1-visitorckw@gmail.com
[trini: Re-sort MAINTAINERS entries]
Signed-off-by: Tom Rini

m68k: Add support for M68040 CPU

2026-02-02T20:24:41+00:00

Add support for the Motorola 68040 architecture. Currently, m68k
support in U-Boot is primarily focused on ColdFire variants. Introduce
the necessary infrastructure to support the classic M680x0 series,
specifically targeting the M68040 as emulated by QEMU.

The implementation includes exception vectors, early startup code, and
minimal CPU initialization and relocation stubs. It also defines the
standard m68k boot information structure used for passing hardware
information to the operating system. To ensure compatibility, ColdFire-
specific library objects such as cache and interrupt handling are
excluded from the build when M68040 is selected.

Additionally, apply a specific workaround during the early memory
reservation stage. Use a manual loop to clear global data instead of
the standard memset() function, as utilizing memset() at this point was
observed to cause a hang on the QEMU platform.

Signed-off-by: Kuan-Wei Chiu 
Acked-by: Angelo Dureghello 
Reviewed-by: Simon Glass

m68k: Update linker scripts to ensure appended device tree is aligned

2026-01-20T18:07:14+00:00

With commit 0535e46d55d7 ("scripts/dtc: Update to upstream version
v1.7.2-35-g52f07dcca47c") it is now a fatal error to U-Boot if our
device tree is not 8-byte aligned. In commit 85f586035d75 ("ARM: OMAP2+:
Pad SPL binary to 8-byte alignment before DTB") Beleswar Padhi explains
that we must have ALIGN(x) statements inside of a section to ensure that
padding is included and not simply that the linker address counter is
incremented. To that end, this patch:
- Remove part of what Marek Vasut did in commit 9ed99e2eeadb ("m68k:
  Assure end of U-Boot is at 8-byte aligned offset") as we now better
  understand what can trigger failure and check for it.
- Rewrite the '.dynsym' section to follow modern practices, and include
  the 8-byte alignment at the end of the section.
- Ensure that we do have alignment by adding an ASSERT so that when not
  aligned we fail to link (and explain why).

Signed-off-by: Tom Rini

m68k: Assure end of U-Boot is at 8-byte aligned offset

2026-01-02T20:20:16+00:00

Make sure the end of U-Boot is at 8-byte aligned offset, not 4-byte
aligned offset. This allows safely appending DT at the end of U-Boot
with the guarantee that the DT will be at 8-byte aligned offset. This
8-byte alignment is now checked by newer libfdt 1.7.2 .

Signed-off-by: Marek Vasut

global_data: Move pci_clk to m68k and powerpc

2024-08-26T20:05:37+00:00

Only m68k and powerpc use this field, so move it to the arch-specific
info, to reduce the size for other archs.

Signed-off-by: Simon Glass

m68k: remove dead code

2024-06-16T10:13:47+00:00

There are no calls of "watchdog_reset()" anymore anywhere in the tree
since the WATCHDOG_RESET macro got removed in 942d07df0e79 ("watchdog:
Remove WATCHDOG_RESET macro").

The only places the identifiers watchdog_disable and watchdog_init are
called are in arch/arm/mach-omap2/, so those can obviously not refer
to these instances.

Hence these functions are not actually used at all and can be
removed. As a bonus, this also removes two leftover references to
WATCHDOG_RESET.

Cc: Huan Wang 
Cc: Angelo Dureghello 
Signed-off-by: Rasmus Villemoes 
Reviewed-by: Stefan Roese

m68k: Remove common.h usage

2023-10-24T20:34:45+00:00

We can remove common.h from most cases of the code here, and only a few
places need an additional header instead.

Signed-off-by: Tom Rini 
Acked-by: Angelo Dureghello

arch: m68k: Implement relocation

2023-09-06T11:28:58+00:00

Implement relocation for M68K. Perform all the updates in start.S
relocate_code in assemby, since it is a simple matter of traversing
the dynsym table and adding relocation offset - MONITOR_BASE to all
the items in that table. The necessity to deal with MONITOR_BASE is
a specific of M68K, where the ELF entry point is at offset 0x400,
which is the MONITOR_BASE, while TEXT_BASE is at offset 0 .

This also removes the one last user of NEEDS_MANUAL_RELOC, so that
could be finally cleaned up .

Reviewed-by: Simon Glass 
Signed-off-by: Marek Vasut

m68k: move watchdog functions in mcf_wdt driver

2023-07-25T21:21:42+00:00

Move watchdog functions inside a separate watchdog driver.

Signed-off-by: Angelo Dureghello 
---
Changes for v2:
- none
Changes for v3:
- none

arch: m68k: Add QEMU specific RAMBAR workaround

2023-04-15T19:36:07+00:00

The QEMU emulation of m68k does not support RAMBAR accesses,
add Kconfig option which inhibits those accesses, so that
U-Boot can be started in m68k QEMU for CI testing purpopses
until QEMU emulation improves.

Signed-off-by: Marek Vasut