From: Jonathan Cameron <jic23@kernel.org>
To: David Lechner <dlechner@baylibre.com>
Cc: Marcelo Schmitt <marcelo.schmitt@analog.com>,
lars@metafoo.de, Michael.Hennerich@analog.com,
robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
conor+dt@kernel.org, marcelo.schmitt1@gmail.com,
linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] iio: adc: Add support for AD4000
Date: Sun, 24 Mar 2024 12:45:46 +0000 [thread overview]
Message-ID: <20240324124546.2e07f802@jic23-huawei> (raw)
In-Reply-To: <CAMknhBH7umcBD0hyt=6fOKu9E8k=CSrnNE4Z+9ynn0F4B=Wk2w@mail.gmail.com>
On Sat, 23 Mar 2024 16:53:17 -0500
> > +
> > + /*
> > + * DMA (thus cache coherency maintenance) requires the
> > + * transfer buffers to live in their own cache lines.
> > + */
> > + union {
> > + struct {
> > + u8 sample_buf[4];
> > + s64 timestamp;
>
> Usually we see __aligned(8) applied to the timestamp (I'm guessing
> some archs need it?)
>
Good spot. Yes, x86_32 is the one that we most commonly refer to for this.
It aligns s64 to only 32 bits whereas IIO ABI is always naturally aligned.
> > + } scan;
> > + u8 d8[2];
> > + } data __aligned(IIO_DMA_MINALIGN);
> > +};
next prev parent reply other threads:[~2024-03-24 12:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-22 22:04 [PATCH 0/2] Add support for AD4000 series Marcelo Schmitt
2024-03-22 22:05 ` [PATCH 1/2] dt-bindings: iio: adc: Add AD4000 Marcelo Schmitt
2024-03-22 23:28 ` Rob Herring
2024-03-23 3:29 ` Marcelo Schmitt
2024-03-23 10:58 ` Krzysztof Kozlowski
2024-03-23 18:44 ` Jonathan Cameron
2024-03-23 20:18 ` David Lechner
2024-03-23 20:38 ` David Lechner
2024-03-23 21:35 ` Marcelo Schmitt
2024-03-22 22:05 ` [PATCH 2/2] iio: adc: Add support for AD4000 Marcelo Schmitt
2024-03-23 19:12 ` Jonathan Cameron
2024-03-23 21:53 ` David Lechner
2024-03-24 12:45 ` Jonathan Cameron [this message]
2024-03-25 13:35 ` David Lechner
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