From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Mark Brown <broonie@kernel.org>,
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>,
Serge Semin <fancer.lancer@gmail.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 14:13:40 +0300 [thread overview]
Message-ID: <20200522111340.GX1634618@smile.fi.intel.com> (raw)
In-Reply-To: <20200522000806.7381-2-Sergey.Semin@baikalelectronics.ru>
On Fri, May 22, 2020 at 03:07:50AM +0300, Serge Semin wrote:
> Since DMA transfers are performed asynchronously with actual SPI
> transaction, then even if DMA transfers are finished it doesn't mean
> all data is actually pushed to the SPI bus. Some data might still be
> in the controller FIFO. This is specifically true for Tx-only
> transfers. In this case if the next SPI transfer is recharged while
> a tail of the previous one is still in FIFO, we'll loose that tail
> data. In order to fix this lets add the wait procedure of the Tx/Rx
> SPI transfers completion after the corresponding DMA transactions
> are finished.
...
> Fixes: 7063c0d942a1 ("spi/dw_spi: add DMA support")
Usually we put this before any other tags.
> Cc: Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>
> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: Paul Burton <paulburton@kernel.org>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Cc: Rob Herring <robh+dt@kernel.org>
Are you sure Rob needs this to see?
You really need to shrink Cc lists of the patches to send them on common sense basis.
> Cc: linux-mips@vger.kernel.org
> Cc: devicetree@vger.kernel.org
Ditto.
...
> Changelog v4:
> - Get back ndelay() method to wait for an SPI transfer completion.
> spi_delay_exec() isn't suitable for the atomic context.
OTOH we may teach spi_delay_exec() to perform atomic sleeps.
...
> + while (dw_spi_dma_tx_busy(dws) && retry--)
> + ndelay(ns);
I might be mistaken, but I think I told that this one misses to keep power
management in mind.
Have you read Documentation/process/volatile-considered-harmful.rst ?
...
> + while (dw_spi_dma_rx_busy(dws) && retry--)
> + ndelay(ns);
Ditto.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2020-05-22 11:13 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 ` Andy Shevchenko [this message]
[not found] ` <20200522115235.rt3ay7lveimrgooa@mobilestation>
2020-05-22 12:10 ` [PATCH v4 01/16] spi: dw: Add Tx/Rx finish wait methods to the MID DMA Mark Brown
2020-05-22 12:12 ` Andy Shevchenko
2020-05-22 12:18 ` Mark Brown
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
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