Re: [PATCH net-next v4 2/2] net: pse-pd: add Realtek/Broadcom PSE MCU driver

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Premature probe failure due to unhandled -EBADMSG during MCU discovery.
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commit f15f1883adfcb0dd6df322e408ed55d0bfd48ac7
Author: Jonas Jelonek <jelonek.jonas@gmail.com>
Subject: net: pse-pd: add Realtek/Broadcom PSE MCU driver

This commit adds a driver for the microcontroller fronting Realtek and
Broadcom PSE chips over I2C or UART. It abstracts the underlying protocol
dialects behind shared core logic and transport modules.

> diff --git a/drivers/net/pse-pd/realtek-pse-mcu-core.c b/drivers/net/pse-pd/realtek-pse-mcu-core.c
> new file mode 100644
> index 0000000000000..11a0abece37bd
> --- /dev/null
> +++ b/drivers/net/pse-pd/realtek-pse-mcu-core.c
[ ... ]
> +static int rtpse_mcu_discover(struct rtpse_mcu_ctrl *pse, struct rtpse_mcu_info *info)
> +{
> +	struct rtpse_mcu_ext_config ext_config;
> +	unsigned long deadline;
> +	int ret;
> +
> +	/*
> +	 * The MCU may not answer on the bus yet right after power-up or
> +	 * enable-gpios assertion: depending on the transport it either stays
> +	 * silent (-ETIMEDOUT) or does not ACK its address at all (-ENXIO /
> +	 * -EREMOTEIO). Retry within a bounded wall-time window so a slow boot
> +	 * still probes, while a genuinely unresponsive MCU fails with its real
> +	 * error instead of deferring forever and masking it.
> +	 */
> +	deadline = jiffies + msecs_to_jiffies(RTPSE_MCU_BOOT_TIMEOUT_MS);
> +	do {
> +		ret = rtpse_mcu_get_info(pse, info);
> +		if (ret != -ETIMEDOUT && ret != -ENXIO && ret != -EREMOTEIO &&
> +		    ret != -EAGAIN)
> +			break;

[Severity: Medium]
Will this prematurely abort the probe if the MCU emits transient garbage
during its boot sequence?

Looking at rtpse_mcu_do_xfer(), it returns -EBADMSG if there is a checksum
mismatch, or if the MCU responds with RTPSE_MCU_OPCODE_BAD_CSUM. If a partially
booted MCU produces invalid bytes on the bus during this startup window,
rtpse_mcu_discover() will immediately break out of the retry loop and fail
the probe since -EBADMSG is not in the allowed list of retry errors.

> +		msleep(RTPSE_MCU_BOOT_RETRY_MS);
> +	} while (time_before(jiffies, deadline));

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Sashiko AI review · https://sashiko.dev/#/patchset/20260630105651.756058-1-jelonek.jonas@gmail.com?part=2