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From: Vincent Whitchurch <vincent.whitchurch@axis.com>
To: Mark Brown <broonie@kernel.org>
Cc: <krzysztof.kozlowski@linaro.org>, <andi@etezian.org>,
	<kernel@axis.com>, <alim.akhtar@samsung.com>,
	<linux-spi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-samsung-soc@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 4/4] spi: s3c64xx: Fix large transfers with DMA
Date: Mon, 26 Sep 2022 15:42:30 +0200	[thread overview]
Message-ID: <YzGsRkyf9tyvjvBy@axis.com> (raw)
In-Reply-To: <Yyh+5ZWXel9SHuWi@sirena.org.uk>

On Mon, Sep 19, 2022 at 03:38:29PM +0100, Mark Brown wrote:
> On Fri, Sep 16, 2022 at 01:39:51PM +0200, Vincent Whitchurch wrote:
> > The COUNT_VALUE in the PACKET_CNT register is 16-bit so the maximum
> > value is 65535.  Asking the driver to transfer a larger size currently
> > leads to the DMA transfer timing out.  Fix this by splitting the
> > transfer as needed.
> 
> The driver should just set max_transfer_size and let the core
> handle this.

Hmm, AFAICS, the core doesn't actually do anything with
max_transfer_size?  It's only used from spi-mem and a handful of other
clients via spi_max_transfer_size().

WARNING: multiple messages have this Message-ID (diff)
From: Vincent Whitchurch <vincent.whitchurch@axis.com>
To: Mark Brown <broonie@kernel.org>
Cc: <krzysztof.kozlowski@linaro.org>, <andi@etezian.org>,
	<kernel@axis.com>, <alim.akhtar@samsung.com>,
	<linux-spi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-samsung-soc@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 4/4] spi: s3c64xx: Fix large transfers with DMA
Date: Mon, 26 Sep 2022 15:42:30 +0200	[thread overview]
Message-ID: <YzGsRkyf9tyvjvBy@axis.com> (raw)
In-Reply-To: <Yyh+5ZWXel9SHuWi@sirena.org.uk>

On Mon, Sep 19, 2022 at 03:38:29PM +0100, Mark Brown wrote:
> On Fri, Sep 16, 2022 at 01:39:51PM +0200, Vincent Whitchurch wrote:
> > The COUNT_VALUE in the PACKET_CNT register is 16-bit so the maximum
> > value is 65535.  Asking the driver to transfer a larger size currently
> > leads to the DMA transfer timing out.  Fix this by splitting the
> > transfer as needed.
> 
> The driver should just set max_transfer_size and let the core
> handle this.

Hmm, AFAICS, the core doesn't actually do anything with
max_transfer_size?  It's only used from spi-mem and a handful of other
clients via spi_max_transfer_size().

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  reply	other threads:[~2022-09-26 15:09 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-16 11:39 [PATCH 0/4] spi: Fix DMA bugs in (not only) spi-s3c64xx Vincent Whitchurch
2022-09-16 11:39 ` Vincent Whitchurch
2022-09-16 11:39 ` [PATCH 1/4] spi: spi-loopback-test: Add test to trigger DMA/PIO mixing Vincent Whitchurch
2022-09-16 11:39   ` Vincent Whitchurch
2022-09-19 14:41   ` Mark Brown
2022-09-19 14:41     ` Mark Brown
2022-09-16 11:39 ` [PATCH 2/4] spi: Save current RX and TX DMA devices Vincent Whitchurch
2022-09-16 11:39   ` Vincent Whitchurch
2022-09-16 11:39 ` [PATCH 3/4] spi: Fix cache corruption due to DMA/PIO overlap Vincent Whitchurch
2022-09-16 11:39   ` Vincent Whitchurch
2022-09-16 16:06   ` kernel test robot
2022-09-16 16:06     ` kernel test robot
2022-09-16 11:39 ` [PATCH 4/4] spi: s3c64xx: Fix large transfers with DMA Vincent Whitchurch
2022-09-16 11:39   ` Vincent Whitchurch
2022-09-19  9:43   ` Krzysztof Kozlowski
2022-09-19  9:43     ` Krzysztof Kozlowski
2022-09-19 14:38   ` Mark Brown
2022-09-19 14:38     ` Mark Brown
2022-09-26 13:42     ` Vincent Whitchurch [this message]
2022-09-26 13:42       ` Vincent Whitchurch
2022-09-26 13:52       ` Mark Brown
2022-09-26 13:52         ` Mark Brown
2022-09-19 16:50 ` (subset) [PATCH 0/4] spi: Fix DMA bugs in (not only) spi-s3c64xx Mark Brown
2022-09-19 16:50   ` Mark Brown

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