Re: [PATCH 1/2] dt-bindings: clock: airoha: Add additional reset for PCIe PERSTOUT

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Unprotected read-modify-write race condition in `en7523_reset_update()`
--

--- Patch [1]: [PATCH 1/2] dt-bindings: clock: airoha: Add additional reset for PCIe PERSTOUT ---
commit 18436d020bf626a2783583bd282cd113ebcf4808
Author: Christian Marangi <ansuelsmth@gmail.com>

dt-bindings: clock: airoha: Add additional reset for PCIe PERSTOUT

This commit adds three new reset identifiers for PCIe PERSTOUT lines to the 
Airoha EN7581 reset bindings.

> diff --git a/include/dt-bindings/reset/airoha,en7581-reset.h b/include/dt-bindings/reset/airoha,en7581-reset.h
> index 6544a1790b83b..25e75534daa94 100644
> --- a/include/dt-bindings/reset/airoha,en7581-reset.h
> +++ b/include/dt-bindings/reset/airoha,en7581-reset.h
> @@ -62,5 +62,9 @@
>  #define EN7581_CPU_TIMER_RST		50
>  #define EN7581_PCIE_HB_RST		51
>  #define EN7581_XPON_MAC_RST		52
> +/* RST_PCIC */
> +#define EN7581_PCIC_PERSTOUT0_RST	53
> +#define EN7581_PCIC_PERSTOUT1_RST	54
> +#define EN7581_PCIC_PERSTOUT2_RST	55

[Severity: High]
This is a pre-existing issue, but does adding these new reset lines expose a
race condition in the driver's reset handler?

Looking at en7523_reset_update() in drivers/clk/clk-en7523.c, the code
performs an unprotected read-modify-write on the shared reset register:

drivers/clk/clk-en7523.c:en7523_reset_update() {
	...
	val = readl(addr);
	if (assert)
		val |= BIT(id % RST_NR_PER_BANK);
	else
		val &= ~BIT(id % RST_NR_PER_BANK);
	writel(val, addr);
	...
}

If two independent consumer drivers call reset_control_assert() or
reset_control_deassert() concurrently for different reset IDs that reside in
the same 32-bit register bank, can one of the updates be silently dropped?

Since the reset framework delegates hardware-level locking to the provider
driver, it seems a spinlock is needed here to prevent concurrent updates
from clobbering each other, which might leave a device permanently in reset
or prematurely pull it out of reset.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260723190133.22577-1-ansuelsmth@gmail.com?part=1