From: Vinod <vkoul@kernel.org>
To: Guodong Xu <guodong.xu@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
dan.j.williams@intel.com, liyu65@hisilicon.com,
Suzhuangluan <suzhuangluan@hisilicon.com>,
"xuhongtao (A)" <xuhongtao8@hisilicon.com>,
zhongkaihua <zhongkaihua@huawei.com>,
Xuezhiliang <xuezhiliang@hisilicon.com>,
"xupeng (Q)" <xupeng7@huawei.com>,
sunliang10@huawei.com, "Fengbaopeng (kevin,
Kirin Solution Dept)" <fengbaopeng@hisilicon.com>,
dmaengine@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] k3dma: add support to reserved minimum channels
Date: Fri, 6 Jul 2018 11:39:38 +0530 [thread overview]
Message-ID: <20180706060938.GU22377@vkoul-mobl> (raw)
In-Reply-To: <CAFGCpxwkdJQAf9bwHTLp+Zc5ASbnFQn9UDsA+zFCH7UZJy9aBQ@mail.gmail.com>
On 06-07-18, 11:05, Guodong Xu wrote:
> On Thu, Jun 28, 2018 at 2:02 PM Vinod <vkoul@kernel.org> wrote:
> >
> > On 22-06-18, 11:24, Guodong Xu wrote:
> > > From: Li Yu <liyu65@hisilicon.com>
> > >
> > > On k3 series of SoC, DMA controller reserves some channels for
> > > other on-chip coprocessors. By adding support to dma_min_chan, kernel
> > > will not be able to use these reserved channels.
> > >
> > > One example is on Hi3660 platform, channel 0 is reserved to lpm3.
> > >
> > > Please also refer to Documentation/devicetree/bindings/dma/k3dma.txt
> >
> > and if some other platform has channel X marked for co-processor, maybe
> > a last channel or something in middle, how will this work then?
> >
> Hi， Vinod
>
> Sorry for delayed response. We checked with Kirin hardware design
> team, so far their design strategy is all Kirin SoC series reserve
> only from minimum side, saying channel 0, then 1, then 2. That impacts
> the current SoC in upstreaming, Kirin960 (Hi3660), and next versions
> in Kirin SoC, Kirin970 and 980, which may hit upstream later.
And what guarantees that they will not change their mind..
> > I am thinking this should be a mask, rather than min.
> >
>
> So, since this driver k3dma.c is only used by Kirin SoC DMA
> controllers, I would prefer to keep the current design dma_min_chan
> unchanged.
>
> What do you think?
I would still prefer bitmask to expose the channels you are supposed to
use
--
~Vinod
next prev parent reply other threads:[~2018-07-06 6:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-22 3:24 [PATCH 0/3] k3dma: add support to reserved channels Guodong Xu
2018-06-22 3:24 ` [PATCH 1/3] dt-bindings: k3dma: add optional property dma_min_chan Guodong Xu
2018-06-28 6:00 ` Vinod
2018-07-03 18:54 ` Rob Herring
2018-07-04 1:14 ` Guodong Xu
2018-07-06 3:17 ` Guodong Xu
2018-06-22 3:24 ` [PATCH 2/3] k3dma: add support to reserved minimum channels Guodong Xu
2018-06-28 6:02 ` Vinod
2018-07-06 3:05 ` Guodong Xu
2018-07-06 6:09 ` Vinod [this message]
2018-06-22 3:24 ` [PATCH 3/3] k3dma: delete axi_config Guodong Xu
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