[PATCH v7 0/3] hwrng: add hwrng support for Rockchip RK3568

Daniel Golle
2024-07-14T15:16:44Z

Rockchip SoCs used to have a random number generator as part of their
crypto device.

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

Tested on FriendlyARM NanoPi R5C.

v6 -> v7:
* Patch 1: unchanged

* Patch 2: bring back rk_rng_write_ctl()
- bring back rk_rng_write_ctl() with improved comment to describe
the hardware.

* Patch 3: unchaned

v5 -> v6:
* Patch 1: unchanged

* Patch 2: get rid of #ifdef
- use if (IS_ENABLED(...)) { ... }instead of #ifdef inside functions
- use __maybe_unused for functions previously enclosed by #ifdef'ery

* Patch 3: unchanged

v4 -> v5:
* Patch 1: always use RK3568 name
- use full RK3568 name in patch description
- add RK3568 to title in binding

* Patch 2: full name and cosmetics
- also always mention RK3568 as there may be other RNG in other
(future) Rockchip SoCs
- remove debug output on successful probe
- use MODULE_AUTHOR several times instead of single comma-separated

* Patch 3: unchanged

v3 -> v4:
* Patch 1: minor corrections
- fix Rokchip -> Rockchip typo
- change commit title as requested

* Patch 2: improved error handling and resource management
- Always use writel() instead of writel_relaxed()
- Use pm_runtime_resume_and_get
- Correctly return error code in rk_rng_read()
- Make use of devm_reset_control_array_get_exclusive
- Use devm_pm_runtime_enable and there by get rid of rk_rng_remove()

* Patch 3:
- Move node to conform with ordering by address

v2 -> v3: patch adopted by Daniel Golle
* 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 RK3568 TRNG
hwrng: add hwrng driver for Rockchip RK3568 SoC
arm64: dts: rockchip: add DT entry for RNG to RK356x

.../bindings/rng/rockchip,rk3568-rng.yaml | 61 +++++
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 | 227 ++++++++++++++++++
6 files changed, 319 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