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Date: Tue, 22 Apr 2014 10:30:36 -0500
Message-ID: <CAL_JsqJktpEBE1rAXDKX8uNSrWzgP1Scucvzrtw0auQSC=SO_g@mail.gmail.com>
Subject: Re: [PATCH v2 0/7] of: setup dma parameters using dma-ranges and dma-coherent
From: Rob Herring <robherring2@gmail.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
        Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
        Santosh Shilimkar <santosh.shilimkar@ti.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        Russell King <linux@arm.linux.org.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        "grant.likely@linaro.org" <grant.likely@linaro.org>,
        Rob Herring <robh+dt@kernel.org>, Olof Johansson <olof@lixom.net>,
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	<linux-arm-kernel@lists.infradead.org>,
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	<gregory.clement@free-electrons.com>,
        Ezequiel Garcia <ezequiel.garcia@free-electrons.com>,
        Lior Amsalem <alior@marvell.com>, Tawfik Bayouk <tawfik@marvell.com>
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On Tue, Apr 22, 2014 at 10:25 AM, Catalin Marinas
<catalin.marinas@arm.com> wrote:
> On Tue, Apr 22, 2014 at 04:02:19PM +0100, Arnd Bergmann wrote:
>> On Saturday 19 April 2014, Thomas Petazzoni wrote:

[...]

>> I would hope we can find a way to avoid the platform notifiers for
>> mvebu as well and come up with a generic way to express this
>> 'semi-coherent' mode. I believe x-gene has a similar issue, and
>> I wouldn't be surprised if there are others like this.
>
> The solution is for the snooping unit to detect the DSB instruction
> (which is propagated outside the CPU) and wait for the completion of the
> coherency work (but we need more information from the hardware guys).

If the solution was fixing broken h/w, we'd all be retired (or h/w
designers). :)

Rob
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