Re: [PATCH v15 01/15] accel/rocket: request the core clocks by name

[Heiko Stübner]

Am Sonntag, 1. November 2026, 09:22:53 Mitteleuropäische Normalzeit schrieb Jiaxing Hu:
> From: Igor Paunovic <royalnet026@xxxxxxxxx>
> 
> rocket_core_init() hands core->clks to devm_clk_bulk_get() without ever
> setting the .id members. The rocket_core array is allocated with
> devm_kcalloc() in rocket_device_init(), and rocket_probe() only fills in
> .rdev, .dev and .index, so all four clk_bulk_data entries are requested
> with a NULL con_id (unlike core->resets, whose ids are set a few lines
> above).
> 
> clk_get(dev, NULL) ends up in of_clk_get_hw(np, 0, NULL), and
> of_parse_clkspec() only consults "clock-names" when a name was passed, so
> the index stays 0 for all four entries. Every entry therefore ends up
> holding a handle to the *first* clock of the DT "clocks" property, i.e.
> ACLK_NPUn. Nothing fails: probe succeeds and the driver believes it owns
> four different clocks.
> 
> The consequence is that rocket_device_runtime_resume() prepares and enables
> the AXI clock four times, while hclk, pclk and - most importantly - the NPU
> compute clock ("npu", SCMI_CLK_NPU on RK3588) are never prepared or enabled
> by this driver at all. The NPU still works only because the Rockchip
> power-domain driver sets GENPD_FLAG_PM_CLK and its attach_dev() callback
> walks the device node with of_clk_get() and adds every clock to the pm_clk
> list, so genpd happens to keep the remaining clocks running. The bug is
> therefore latent today, but it means the driver holds no reference to the
> clock that actually feeds the NPU, which stands in the way of any future
> frequency scaling (OPP/devfreq) work.
> 
> Found on an Orange Pi 5 Plus (RK3588) by reading the live clock tree:
> /sys/kernel/debug/clk/clk_summary shows four "fdab0000.npu" consumer
> handles on aclk_npu0 (and likewise on aclk_npu1/aclk_npu2 for the other two
> cores), while hclk_npu0, pclk_npu_root and scmi_clk_npu have no
> "fdab0000.npu" consumer at all - their only consumers are the
> "npu@fdab0000" handles created by the power-domain driver via of_clk_get().
> 
> Set the ids explicitly, in the order mandated by the binding
> (Documentation/devicetree/bindings/npu/rockchip,rk3588-rknn-core.yaml):
> aclk, hclk, npu, pclk. After the change the driver holds one handle per
> distinct clock and clk_bulk_prepare_enable() covers all four.
> 
> Note that this is a user-visible tightening for out-of-tree DTs: the old
> NULL-id requests resolved by index and succeeded no matter what
> "clock-names" contained, while the named requests fail probe with -ENOENT
> when one of the four names is missing. That is the right outcome for
> in-tree users - the binding requires exactly these four clock-names and
> rk3588-base.dtsi carries them on all three cores - but a DT that relied on
> the permissive lookup goes from silently running on the wrong clock handles
> to not probing at all, so record the change here where git log will find
> it.
> 
> Fixes: ed98261b4168 ("accel/rocket: Add a new driver for Rockchip's NPU")
> Signed-off-by: Igor Paunovic <royalnet026@xxxxxxxxx>
> Tested-by: Sidong Yang <sidong.yang@xxxxxxxxxx>
> Tested-by: Diederik de Haas <diederik@xxxxxxxxxxxxxx>  # NanoPC-T6 LTS, NanoPC-T6 Plus
> Reviewed-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
> Reviewed-by: Jiaxing Hu <gahing@xxxxxxxxxxxxx>
> Signed-off-by: Jiaxing Hu <gahing@xxxxxxxxxxxxx>

Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>

nit: the commit description could be way shorter, for that small change.