Re: [PATCH v2 05/11] accel/rocket: request the core clocks by name

["Heiko Stübner" <heiko@sntech.de>]

Am Dienstag, 22. September 2026, 10:01:08 Mitteleuropäische Normalzeit schrieb Igor Paunovic:
> 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")
> Assisted-by: LLM sparse checkpatch
> Signed-off-by: Igor Paunovic <royalnet026@gmail.com>
> Tested-by: Sidong Yang <sidong.yang@furiosa.ai>
> Tested-by: Diederik de Haas <diederik@cknow-tech.com>  # NanoPC-T6 LTS, NanoPC-T6 Plus
> Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> Reviewed-by: Jiaxing Hu <gahing@gahingwoo.com>
> ---
> Same diff and the same message text (his copy re-wraps the lines) as
> 01/14 of Jiaxing Hu's RK3576 series, which carries this patch as well;
> whichever lands first, the other drops it. The trailers differ: Jiaxing
> asked me to drop his Signed-off-by from my own posting of it, as he did
> not pass this copy along, and Assisted-by is added because an LLM helped
> with the checks on this v2.
> 
>  drivers/accel/rocket/rocket_core.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/accel/rocket/rocket_core.c b/drivers/accel/rocket/rocket_core.c
> index b3b2fa9ba645a..5dd260bacbff6 100644
> --- a/drivers/accel/rocket/rocket_core.c
> +++ b/drivers/accel/rocket/rocket_core.c
> @@ -28,6 +28,10 @@ int rocket_core_init(struct rocket_core *core)
>  	if (err)
>  		return dev_err_probe(dev, err, "failed to get resets for core %d\n", core->index);
>  
> +	core->clks[0].id = "aclk";
> +	core->clks[1].id = "hclk";
> +	core->clks[2].id = "npu";
> +	core->clks[3].id = "pclk";

additionally, while reading the followup patches, please introduce some
constants for the indices. ROCKET_CLK_ACLK, ... or some other name.
Because when you access them later by index, that makes things harder
to read and follow (especially in the future)


Heiko