linux-kernel - Re: [PATCH] spi: set right CS polarity depend on gpiolib

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210507153009.GB6383@sirena.org.uk>
Date:   Fri, 7 May 2021 16:30:09 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Liguang Zhang <zhangliguang@...ux.alibaba.com>
Cc:     linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] spi: set right CS polarity depend on gpiolib

On Fri, May 07, 2021 at 10:51:17PM +0800, Liguang Zhang wrote:
> After a kernel upgrade from 4.19 to 5.10, we found that tpm flow control
> always causes TIMEOUT which caused by wrong CS polarity setting depend
> on gpiolib.

>  			if (spi->cs_gpiod)
>  				/* polarity handled by gpiolib */
> -				gpiod_set_value_cansleep(spi->cs_gpiod, activate);
> +				gpiod_set_value_cansleep(spi->cs_gpiod, !enable);

Whatever is going on here it doesn't seem likely that this is a problem
in the SPI core given the widespread use of gpiod based chip selects -
can you provide more explanation of what you're seeing here, how is the
chip select configured, what is the hardware expectation and what
actually ends up happening?

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)