From: Mark Brown <broonie@kernel.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Serge Semin <Sergey.Semin@baikalelectronics.ru>,
Serge Semin <fancer.lancer@gmail.com>,
Linus Walleij <linus.walleij@stericsson.com>,
Vinod Koul <vkoul@kernel.org>, Feng Tang <feng.tang@intel.com>,
Grant Likely <grant.likely@secretlab.ca>,
Alan Cox <alan@linux.intel.com>,
Georgy Vlasov <Georgy.Vlasov@baikalelectronics.ru>,
Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>,
Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Paul Burton <paulburton@kernel.org>,
Ralf Baechle <ralf@linux-mips.org>, Arnd Bergmann <arnd@arndb.de>,
Rob Herring <robh+dt@kernel.org>,
linux-mips@vger.kernel.org, devicetree@vger.kernel.org,
Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Jarkko Nikula <jarkko.nikula@linux.intel.com>,
"wuxu.wu" <wuxu.wu@huawei.com>, Clement Leger <cleger@kalray.eu>,
Linus Walleij <linus.walleij@linaro.org>,
linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 01/16] spi: dw: Add Tx/Rx finish wait methods to the MID DMA
Date: Fri, 22 May 2020 13:18:20 +0100 [thread overview]
Message-ID: <20200522121820.GG5801@sirena.org.uk> (raw)
In-Reply-To: <20200522121221.GA1634618@smile.fi.intel.com>
[-- Attachment #1: Type: text/plain, Size: 770 bytes --]
On Fri, May 22, 2020 at 03:12:21PM +0300, Andy Shevchenko wrote:
> On Fri, May 22, 2020 at 02:52:35PM +0300, Serge Semin wrote:
> > Please, see it's implementation. It does atomic delay when the delay value
> > is less than 10us. But selectively gets to the usleep_range() if value is
> > greater than that.
> Oh, than it means we may do a very long busy loop here which is not good at
> all. If we have 10Hz clock, it might take seconds of doing nothing!
Realistically it seems unlikely that the clock will be even as slow as
double digit kHz though, and if we do I'd not be surprised to see other
problems kicking in. It's definitely good to handle such things if we
can but so long as everything is OK for realistic use cases I'm not sure
it should be a blocker.
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
next prev parent reply other threads:[~2020-05-22 12:18 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-22 0:07 [PATCH v4 00/16] spi: dw: Add generic DW DMA controller support Serge Semin
2020-05-22 0:07 ` [PATCH v4 02/16] spi: dw: Enable interrupts in accordance with DMA xfer mode Serge Semin
2020-05-22 0:07 ` [PATCH v4 04/16] spi: dw: Discard unused void priv pointer Serge Semin
2020-05-22 0:07 ` [PATCH v4 06/16] spi: dw: Parameterize the DMA Rx/Tx burst length Serge Semin
2020-05-22 11:06 ` Andy Shevchenko
2020-05-22 0:07 ` [PATCH v4 07/16] spi: dw: Use DMA max burst to set the request thresholds Serge Semin
2020-05-22 0:08 ` [PATCH v4 11/16] spi: dw: Remove DW DMA code dependency from DW_DMAC_PCI Serge Semin
2020-05-22 0:08 ` [PATCH v4 12/16] spi: dw: Add DW SPI DMA/PCI/MMIO dependency on the DW SPI core Serge Semin
2020-05-22 11:07 ` Andy Shevchenko
2020-05-22 11:08 ` Andy Shevchenko
2020-05-22 0:08 ` [PATCH v4 14/16] spi: dw: Add DMA support to the DW SPI MMIO driver Serge Semin
2020-05-22 0:08 ` [PATCH v4 16/16] dt-bindings: spi: Convert DW SPI binding to DT schema Serge Semin
2020-05-28 23:28 ` Rob Herring
[not found] ` <20200522000806.7381-2-Sergey.Semin@baikalelectronics.ru>
2020-05-22 11:13 ` [PATCH v4 01/16] spi: dw: Add Tx/Rx finish wait methods to the MID DMA Andy Shevchenko
[not found] ` <20200522115235.rt3ay7lveimrgooa@mobilestation>
2020-05-22 12:10 ` Mark Brown
2020-05-22 12:12 ` Andy Shevchenko
2020-05-22 12:18 ` Mark Brown [this message]
2020-05-22 12:34 ` Andy Shevchenko
[not found] ` <20200522124406.co7gmteojfsooerc@mobilestation>
[not found] ` <20200522131013.GH5801@sirena.org.uk>
[not found] ` <20200522132742.taf2ixfjpyd5u3dt@mobilestation>
[not found] ` <20200522140025.bmd6bhpjjk5msvsm@mobilestation>
2020-05-22 14:36 ` Andy Shevchenko
[not found] ` <20200522144542.brhibh453wid2d6v@mobilestation>
2020-05-22 15:22 ` Mark Brown
2020-05-23 8:34 ` Serge Semin
2020-05-25 11:41 ` Mark Brown
2020-05-25 21:36 ` Serge Semin
2020-05-22 11:22 ` [PATCH v4 00/16] spi: dw: Add generic DW DMA controller support Andy Shevchenko
2020-05-22 11:23 ` Andy Shevchenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200522121820.GG5801@sirena.org.uk \
--to=broonie@kernel.org \
--cc=Alexey.Malahov@baikalelectronics.ru \
--cc=Georgy.Vlasov@baikalelectronics.ru \
--cc=Ramil.Zaripov@baikalelectronics.ru \
--cc=Sergey.Semin@baikalelectronics.ru \
--cc=alan@linux.intel.com \
--cc=andriy.shevchenko@linux.intel.com \
--cc=arnd@arndb.de \
--cc=cleger@kalray.eu \
--cc=devicetree@vger.kernel.org \
--cc=fancer.lancer@gmail.com \
--cc=feng.tang@intel.com \
--cc=grant.likely@secretlab.ca \
--cc=jarkko.nikula@linux.intel.com \
--cc=linus.walleij@linaro.org \
--cc=linus.walleij@stericsson.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=linux-spi@vger.kernel.org \
--cc=paulburton@kernel.org \
--cc=ralf@linux-mips.org \
--cc=robh+dt@kernel.org \
--cc=tglx@linutronix.de \
--cc=tsbogend@alpha.franken.de \
--cc=vkoul@kernel.org \
--cc=wan.ahmad.zainie.wan.mohamad@intel.com \
--cc=wuxu.wu@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).