linux-kernel - Re: [PATCH v2 3/3] i2c: mpc: implement erratum A-004447 workaround

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]

Message-ID: <c4fa78e8f2c43da240c932618b87b34ba2d1d046.camel@infinera.com>
Date:   Fri, 7 May 2021 14:52:17 +0000
From:   Joakim Tjernlund <Joakim.Tjernlund@...inera.com>
To:     "andy.shevchenko@...il.com" <andy.shevchenko@...il.com>,
        "chris.packham@...iedtelesis.co.nz" 
        <chris.packham@...iedtelesis.co.nz>
CC:     "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        "andriy.shevchenko@...ux.intel.com" 
        <andriy.shevchenko@...ux.intel.com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "wsa@...nel.org" <wsa@...nel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>
Subject: Re: [PATCH v2 3/3] i2c: mpc: implement erratum A-004447 workaround

On Fri, 2021-05-07 at 14:46 +0300, Andy Shevchenko wrote:
> On Fri, May 7, 2021 at 3:40 AM Chris Packham
> <chris.packham@...iedtelesis.co.nz> wrote:
> > 
> > The P2040/P2041 has an erratum where the normal i2c recovery mechanism
> > does not work. Implement the alternative recovery mechanism documented
> > in the P2040 Chip Errata Rev Q.
> 
> Thanks.
> 
> > +static int i2c_mpc_wait_sr(struct mpc_i2c *i2c, int mask)
> > +{
> > +       int ret;
> > +       u8 val;
> > +
> > +       ret = readb_poll_timeout(i2c->base + MPC_I2C_SR, val,
> > +                                val & mask, 0, 100);
> > +
> > +       return ret;
> > +}
> 
> So, now you may shrink it even further, i.e.
> 
>        void __iomem *sr = i2c->base + MPC_I2C_SR;
>        u8 val;
> 
>        return readb_poll_timeout(sr, val, val & mask, 0, 100);
> 

val looks uninitialised before use?