linux-kernel - Re: [PATCH 03/10] spi: Add flag for no TX after a RX in the same Chip Select

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:   Thu, 9 Sep 2021 11:51:21 +0100
From:   Lucas tanure <tanureal@...nsource.cirrus.com>
To:     Mark Brown <broonie@...nel.org>
CC:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Sanjay R Mehta <sanju.mehta@....com>,
        Nehal Bakulchandra Shah <Nehal-Bakulchandra.shah@....com>,
        <linux-kernel@...r.kernel.org>, <linux-spi@...r.kernel.org>,
        <patches@...nsource.cirrus.com>
Subject: Re: [PATCH 03/10] spi: Add flag for no TX after a RX in the same Chip
 Select

On 9/8/21 1:37 PM, Mark Brown wrote:
> On Wed, Sep 08, 2021 at 12:34:44PM +0100, Lucas Tanure wrote:
>> Some controllers can't write to the bus after a read without
>> releasing the chip select, so add flag and a check in spi core
> 
> Nothing you've added ever reads this flag and I'm not sure what anything
> would be able to constructively do with it so why add the flag?  I don't
> understand what the use case is.
> 
__spi_validate checks this flag and makes sure the message can be 
received by the controller.
__spi_validate can't fix the message, so it only rejects the message.