Re: [PATCH v3 18/47] clk: qcom: gcc-sc7280: Tie the CX power domain to controller

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Enabling runtime PM on the GCC controller (`use_rpm = true`) introduces a crash during reset operations because `qcom_reset_ops` perform raw regmap accesses without taking a runtime PM reference. Asserting a reset when the GCC device is suspended will access unpowered registers.
--

--- Patch [18]: [PATCH v3 18/47] clk: qcom: gcc-sc7280: Tie the CX power domain to controller ---
commit 759cca681f45c71a5a8669a98523e27fad8124b8
Author: Abel Vesa <abel.vesa@oss.qualcomm.com>

clk: qcom: gcc-sc7280: Tie the CX power domain to controller

Enable runtime PM for the controller, allowing CX to be powered down once all
GCC consumers have released their clocks and GDSCs.

> diff --git a/drivers/clk/qcom/gcc-sc7280.c b/drivers/clk/qcom/gcc-sc7280.c
> index 4502926a2691a..bb8f6efb88b1c 100644
> --- a/drivers/clk/qcom/gcc-sc7280.c
> +++ b/drivers/clk/qcom/gcc-sc7280.c
> @@ -3446,6 +3446,7 @@ static const struct qcom_cc_desc gcc_sc7280_desc = {
>  	.num_resets = ARRAY_SIZE(gcc_sc7280_resets),
>  	.gdscs = gcc_sc7280_gdscs,
>  	.num_gdscs = ARRAY_SIZE(gcc_sc7280_gdscs),
> +	.use_rpm = true,

[Severity: High]
Does enabling runtime PM here introduce a potential crash during reset
operations?

Looking at drivers/clk/qcom/reset.c, the reset operations perform raw regmap
accesses without taking a runtime PM reference:

drivers/clk/qcom/reset.c:qcom_reset_set_assert() {
	...
	regmap_update_bits(rst->regmap, map->reg, mask, assert ? mask : 0);
	...
}

If a consumer asserts a reset while the GCC controller is suspended, could
this access unpowered registers and cause a synchronous external abort?

Since the regmap configuration lacks .pm_runtime = true and the reset code
does not wrap the regmap accesses with pm_runtime_resume_and_get(), this
might allow accessing the hardware while the CX domain is powered off.

>  };

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260824-qcom-tie-cx-to-gcc-v3-0-f1205a92682b@oss.qualcomm.com?part=18