From: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
To: Jun Nie <jun.nie@linaro.org>, Christoph Hellwig <hch@infradead.org>
Cc: "ulf.hansson@linaro.org" <ulf.hansson@linaro.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"mark.rutland@arm.com" <mark.rutland@arm.com>,
"adrian.hunter@intel.com" <adrian.hunter@intel.com>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
Subject: Re: [PATCH 4/4] mmc: sdhci: Add DMA memory boundary workaround
Date: Tue, 3 Dec 2019 09:05:23 +0000 [thread overview]
Message-ID: <20191203165123.4e6f9e28@xhacker.debian> (raw)
In-Reply-To: <CABymUCMVi_N2Mt82YDt7wrys4Z_vnXYEu15-YBa+S1CejT9iZw@mail.gmail.com>
+ Christoph
On Tue, 3 Dec 2019 11:33:15 +0800 Jun Nie wrote:
>
>
> Jisheng Zhang <Jisheng.Zhang@synaptics.com> 于2019年12月3日周二 上午10:47写道：
> >
> > On Mon, 2 Dec 2019 22:41:04 +0800 Jun Nie wrote:
> >
> >
> > >
> > >
> > > DMA memory cannot cross specific boundary for some SDHCI controller,
> > > such as DesignWare SDHCI controller. Add DMA memory boundary dt
> > > property and workaround the limitation.
> >
> > IMHO, the workaround could be implemented in each SDHCI host driver.
> >
> > eg. drivers/mmc/host/sdhci-of-dwcmshc.c
> >
> Thanks for the suggestion! Christoph's suggestion can prevent the the issue
> from the block layer, thus the code can be shared across all
To be honest, I did consider similar solution from block layer, I.E set
the seg_boundary_mask, when submitting the workaround last year, but per
my understanding, SDHCI limitation is the physical DMA addr can't span one
specific boundary, so setting seg_boundary_mask w/ blk_queue_segment_boundary
can't work. I'm not sure I understand blk_queue_segment_boundary() properly.
May Christoph help to clarify?
From another side, drivers/ata/libata-sff.c also workaround the 64K phy DMA
boundary limitation itself rather than from block layer.
Thanks
> controllers. I prefer
> his suggestions.
>
> Jun
next prev parent reply other threads:[~2019-12-03 9:05 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-02 14:41 [PATCH 0/4] mmc: Add sdhci workaround stability enhencement Jun Nie
2019-12-02 14:41 ` [PATCH 1/4] mmc: sdhci: Add delay after power off Jun Nie
2019-12-03 7:26 ` Adrian Hunter
2019-12-02 14:41 ` [PATCH 2/4] mmc: sdhci: dt: Add DMA boundary and HS400 properties Jun Nie
2019-12-13 23:01 ` Rob Herring
2019-12-17 14:56 ` Jun Nie
2019-12-02 14:41 ` [PATCH 3/4] mmc: sdhci: Set ctrl_hs400 value in dts Jun Nie
2019-12-03 7:52 ` Adrian Hunter
2019-12-02 14:41 ` [PATCH 4/4] mmc: sdhci: Add DMA memory boundary workaround Jun Nie
2019-12-02 17:52 ` Christoph Hellwig
2019-12-03 3:29 ` Jun Nie
2019-12-03 7:36 ` Christoph Hellwig
2019-12-04 6:00 ` Jun Nie
2019-12-04 7:14 ` Jisheng Zhang
2019-12-10 9:36 ` Ulf Hansson
2019-12-03 2:47 ` Jisheng Zhang
2019-12-03 3:33 ` Jun Nie
2019-12-03 9:05 ` Jisheng Zhang [this message]
2019-12-03 9:18 ` Christoph Hellwig
2019-12-03 9:49 ` Jisheng Zhang
2019-12-03 13:06 ` Christoph Hellwig
2019-12-04 7:11 ` Jisheng Zhang
2019-12-03 9:49 ` Jisheng Zhang
2019-12-03 13:04 ` Christoph Hellwig
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