Date: Sun, 30 Oct 2016 15:41:48 -0500
From: Rob Herring <robh@kernel.org>
To: Niklas Cassel <niklas.cassel@axis.com>
Cc: vinod.koul@intel.com, mark.rutland@arm.com, dan.j.williams@intel.com,
        dmaengine@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, Niklas Cassel <niklass@axis.com>
Subject: Re: [PATCH] dmaengine: nbpfaxi: add optional max-burst property for
 memory reads/writes
Message-ID: <20161030204147.ysm6vsubfclae57y@rob-hp-laptop>
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On Mon, Oct 24, 2016 at 03:29:15PM +0200, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@axis.com>
> 
> Due to a hardware bug, reading memory (from the Accelerator Coherency Port)
> with a burst size equal to the maximum burst size allowed by the DMA
> hardware's buffer size will cause a hardware hang on the ARTPEC-6 SoC,
> where the only solution is a manual power cycle.
> On ARTPEC-6, this hardware bug does not trigger when writing memory (to the
> Accelerator Coherency Port) with a burst size equal to the maximum burst
> size allowed by the DMA hardware's buffer size.
> 
> To avoid this hardware hang, introduce a new optional max-burst property
> for memory reads. For completeness, also introduce a max-burst property for
> memory writes.
> 
> Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
> ---
>  Documentation/devicetree/bindings/dma/nbpfaxi.txt |  8 +++++
>  drivers/dma/nbpfaxi.c                             | 38 ++++++++++++++++++++---
>  2 files changed, 42 insertions(+), 4 deletions(-)

Acked-by: Rob Herring <robh@kernel.org>