From mboxrd@z Thu Jan  1 00:00:00 1970
From: Clemens Ladisch <clemens@ladisch.de>
Subject: Re: Question on arm64 unaligned faults during playback
Date: Tue, 09 Dec 2014 09:19:55 +0100
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To: Abhilash Kesavan <kesavan.abhilash@gmail.com>, Catalin Marinas <catalin.marinas@arm.com>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>, Lars-Peter Clausen <lars@metafoo.de>, "padma.v@samsung.com" <padma.v@samsung.com>, Takashi Iwai <tiwai@suse.de>, Will Deacon <Will.Deacon@arm.com>, "lgirdwood@gmail.com" <lgirdwood@gmail.com>, "broonie@kernel.org" <broonie@kernel.org>, "p.zabel@pengutronix.de" <p.zabel@pengutronix.de>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>
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Abhilash Kesavan wrote:
> Currently, if I continue to use the SRAM allocation driver, two
> options are working:
> 1) ioremap to ioremap_wc in drivers/misc/sram.c.
> 2) copy_from_user to copy_from_user_toio in sound/core/pcm_lib.c
>
> Which would be the preferred option ?

I don't know how to tell the SRAM allocator to hand out WC memory, but
copy_from_user_toio() is what you would put into your .copy callback.


Regards,
Clemens

From mboxrd@z Thu Jan  1 00:00:00 1970
From: clemens@ladisch.de (Clemens Ladisch)
Date: Tue, 09 Dec 2014 09:19:55 +0100
Subject: [alsa-devel] Question on arm64 unaligned faults during playback
In-Reply-To: <CAM4voam0h4e1Z8q3eqNpgMhhfw-zJpfh7fi4iznX_Y0bj98nKA@mail.gmail.com>
References: <CAM4voa=kiLsiLEzUbo3D+f1go5px78fXBSjSi7kGK4QCdnwPyQ@mail.gmail.com>	<54856621.8090107@ladisch.de>
 <s5hppbumnis.wl-tiwai@suse.de>	<54858868.70708@metafoo.de>	<20141208122549.GF16185@e104818-lin.cambridge.arm.com>
 <CAM4voam0h4e1Z8q3eqNpgMhhfw-zJpfh7fi4iznX_Y0bj98nKA@mail.gmail.com>
Message-ID: <5486B0AB.7000109@ladisch.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Abhilash Kesavan wrote:
> Currently, if I continue to use the SRAM allocation driver, two
> options are working:
> 1) ioremap to ioremap_wc in drivers/misc/sram.c.
> 2) copy_from_user to copy_from_user_toio in sound/core/pcm_lib.c
>
> Which would be the preferred option ?

I don't know how to tell the SRAM allocator to hand out WC memory, but
copy_from_user_toio() is what you would put into your .copy callback.


Regards,
Clemens