[PATCH v3 0/3] hwrng: add hwrng support for Rockchip RK3568

Daniel Golle
2024-06-21T01:25:10Z

Rockchip SoCs used to have a random number generator as part of their
crypto device, and support for it has to be added to the corresponding
driver.

However newer Rockchip SoCs like the RK3568 have an independent True
Random Number Generator device. This patchset adds a driver for it and
enable it in the device tree.

v2 of this patchset has been submitted by Aurelien Jarno in November
2022. A follow-up submission addressing the comments received for v2
never happened.

As I believe that using the TRNG is generally desireable as it reduces
the time needed to boot significantly as userspace no longer waits due
blocking read of /dev/random while still lacking entropy I have picked
up Aurelien's previous work and completed it.

Link to v2: https://patchwork.kernel.org/project/linux-arm-kernel/cover/20221128184718.1963353-1-aurelien@aurel32.net/

v2 -> v3:
* Patch 1: address comments of Krzysztof Kozlowski, add MAINTAINERS
- improved description
- meaningful clock-names
- add entry in MAINTAINERS files

* Patch 2: numerous code-style improvements
- drop misleading rk_rng_write_ctl(), simplify I/O writes
- drop unused TRNG_RNG_DOUT_[1-7] macros
- handle error handling for pm_runtime_get_sync()
- use memcpy_fromio() instead of open coding for-loop
- some minor white-spaces fixes

* Patch 3:
- use clock-names as defined in dt-bindings

v1 -> v2:
* Patch 1: fix issues reported by Rob Herring and Krzysztof Kozlowski:
- Rename rockchip-rng.yaml into rockchip,rk3568-rng.yaml
- Fix binding title and description
- Fix compatible property
- Rename clocks and add the corresponding descriptions
- Drop reset-names
- Add a bus definition with #address-cells and #size-cells to the
example.

* Patch 2: fix issue reported by kernel test robot <lkp@intel.com>
- Do not read the random registers as big endian, looking at the
RK3568 TRM this is actually not needed. This fixes a sparse
warning.

* Patch 3: unchanged

Aurelien Jarno (3):
dt-bindings: RNG: Add Rockchip RNG bindings
hwrng: add Rockchip SoC hwrng driver
arm64: dts: rockchip: add DT entry for RNG to RK356x

.../bindings/rng/rockchip,rk3568-rng.yaml | 60 +++++
MAINTAINERS | 7 +
arch/arm64/boot/dts/rockchip/rk356x.dtsi | 9 +
drivers/char/hw_random/Kconfig | 14 ++
drivers/char/hw_random/Makefile | 1 +
drivers/char/hw_random/rockchip-rng.c | 229 ++++++++++++++++++
6 files changed, 320 insertions(+)
create mode 100644 Documentation/devicetree/bindings/rng/rockchip,rk3568-rng.yaml
create mode 100644 drivers/char/hw_random/rockchip-rng.c

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2.45.2