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Date:   Mon, 8 Aug 2022 15:14:24 +0100
From:   Jonathan Cameron <Jonathan.Cameron@huawei.com>
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
CC:     Jonathan Cameron <jic23@kernel.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        Nuno =?ISO-8859-1?Q?S=E1?= <nuno.sa@analog.com>
Subject: Re: [PATCH 1/4] staging: iio: frequency: ad9832: Fix alignment for
 DMA safety
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On Mon, 8 Aug 2022 11:18:34 +0200
Andy Shevchenko <andy.shevchenko@gmail.com> wrote:

> On Sun, Aug 7, 2022 at 5:26 PM Jonathan Cameron <jic23@kernel.org> wrote:
> >
> > From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> >
> > ____cacheline_aligned is an insufficient guarantee for non-coherent DMA
> > on platforms with 128 byte cachelines above L1.  Switch to the updated
> > IIO_DMA_MINALIGN definition.  
> 
> ...
> 
> >         union {
> > -               __be16                  freq_data[4]____cacheline_aligned;
> > +               __be16                  freq_data[4] __aligned(IIO_DMA_MINALIGN);
> >                 __be16                  phase_data[2];
> >                 __be16                  data;
> >         };  
> 
> Hmm... Can we rather mark the entire union with it?
> 

ah. I'd not even registered it was a union ;)  Anyhow, yes, that would make
sense.