[PATCH v3 0/3] m68k: coldfire: Add RNG support and const qualifiers for MCF54418

Jean-Michel Hautbois posted 3 patches 1 week ago
arch/m68k/coldfire/device.c       | 52 ++++++++++++++++++++++++++++++---------
arch/m68k/coldfire/m5441x.c       |  2 +-
arch/m68k/include/asm/m5441xsim.h |  9 +++++++
drivers/char/hw_random/Kconfig    |  3 ++-
drivers/char/hw_random/imx-rngc.c |  9 ++++++-
5 files changed, 60 insertions(+), 15 deletions(-)
[PATCH v3 0/3] m68k: coldfire: Add RNG support and const qualifiers for MCF54418
Posted by Jean-Michel Hautbois 1 week ago
This series adds support for the MCF54418 hardware random number generator
(RNGB) and improves type safety for platform device resources.

The MCF54418 contains an RNGB hardware block compatible with the imx-rngc
driver. This series enables its use by:
- Adding platform device registration for the RNG hardware
- Enabling the clock at platform initialization
- Making the imx-rngc driver compatible with Coldfire's always-on clock
model using devm_clk_get_optional()

Additionally, following Frank Li's suggestion, all static resource array
in arch/m68k/coldfire/device.c are marked const, moving them to read-only
memory and aligning with kernel API expectations.

Testing on DLC Next board shows:
- Hardware RNG throughput: 26 MB/s
- FIPS 140-2 quality: 0.2% failure rate (rng-tools)
- Boot time improvement: CRNG initialization 7 seconds faster

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>
---
Changes in v3:
- Depend on COLDFIRE is enough
- Split the clock change in a dedicated commit
- Link to v2: https://lore.kernel.org/r/20251107-b4-m5441x-add-rng-support-v2-0-f91d685832b9@yoseli.org

Changes in v2:
- Split const qualifier changes into a separate patch as suggested by
Frank Li
- Mark all resource arrays (including RNG) as const in device.c
- No functional changes to RNG implementation

---
Jean-Michel Hautbois (3):
      m68k: coldfire: Mark platform device resource arrays as const
      hwrng: imx-rngc: Use optional clock
      m68k: coldfire: Add RNG support for MCF54418

 arch/m68k/coldfire/device.c       | 52 ++++++++++++++++++++++++++++++---------
 arch/m68k/coldfire/m5441x.c       |  2 +-
 arch/m68k/include/asm/m5441xsim.h |  9 +++++++
 drivers/char/hw_random/Kconfig    |  3 ++-
 drivers/char/hw_random/imx-rngc.c |  9 ++++++-
 5 files changed, 60 insertions(+), 15 deletions(-)
---
base-commit: ac3fd01e4c1efce8f2c054cdeb2ddd2fc0fb150d
change-id: 20251107-b4-m5441x-add-rng-support-0fdb8d40210a

Best regards,
-- 
Jean-Michel Hautbois <jeanmichel.hautbois@yoseli.org>