From: Robin Gong <yibin.gong@nxp.com>
To: Mark Brown <broonie@kernel.org>
Cc: Vinod Koul <vkoul@kernel.org>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
"festevam@gmail.com" <festevam@gmail.com>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"matthias.schiffer@ew.tq-group.com"
<matthias.schiffer@ew.tq-group.com>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
dl-linux-imx <linux-imx@nxp.com>,
"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v1 RFC 1/2] spi: introduce fallback to pio
Date: Mon, 15 Jun 2020 13:35:01 +0000 [thread overview]
Message-ID: <VE1PR04MB6638C65257F41072C3D61583899C0@VE1PR04MB6638.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20200615123553.GP4447@sirena.org.uk>
On 2020/06/15 20:36 Mark Brown <broonie@kernel.org> wrote:
> On Sun, Jun 14, 2020 at 01:04:57PM +0000, Robin Gong wrote:
>
> Please delete unneeded context from mails when replying. Doing this makes
> it much easier to find your reply in the message, helping ensure it won't be
> missed by people scrolling through the irrelevant quoted material.
Okay, thanks Mark.
>
> > > No, I mean that the reason the DMA transfer fails may be something
> > > that happens after we've started putting things on the bus - the bit
> > > about FIFOs is just a random example of an error that could happen.
>
> > Sorry Mark for that I can't get your point... The bus error such as
> > data corrupt seems not the spi core's business since it can only be
> > caught in spi controller driver or upper level such as mtd driver
> > (spi-nor) which know what's the failure happen at spi bus HW level or
> > what's the correct data/message. In other words, spi core can't detect such
> error by transfer_one().
>
> If we see an error in transfer_one() it could be from anything, we've no idea
> what happened on the bus - the controller may have got part way through the
> transfer before failing.
Then how about choosing specific error code for such dma not ready case where
nothing went out on the bus neither?
>
> > But despite of that case, do you think this patch is valid for
> > transfer_one() failue in dma and fallback to pio?
>
> No, not unless we know that nothing went out on the bus.
WARNING: multiple messages have this Message-ID (diff)
From: Robin Gong <yibin.gong@nxp.com>
To: Mark Brown <broonie@kernel.org>
Cc: "matthias.schiffer@ew.tq-group.com"
<matthias.schiffer@ew.tq-group.com>,
"shawnguo@kernel.org" <shawnguo@kernel.org>,
"s.hauer@pengutronix.de" <s.hauer@pengutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
Vinod Koul <vkoul@kernel.org>, dl-linux-imx <linux-imx@nxp.com>,
"kernel@pengutronix.de" <kernel@pengutronix.de>,
"festevam@gmail.com" <festevam@gmail.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: RE: [PATCH v1 RFC 1/2] spi: introduce fallback to pio
Date: Mon, 15 Jun 2020 13:35:01 +0000 [thread overview]
Message-ID: <VE1PR04MB6638C65257F41072C3D61583899C0@VE1PR04MB6638.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20200615123553.GP4447@sirena.org.uk>
On 2020/06/15 20:36 Mark Brown <broonie@kernel.org> wrote:
> On Sun, Jun 14, 2020 at 01:04:57PM +0000, Robin Gong wrote:
>
> Please delete unneeded context from mails when replying. Doing this makes
> it much easier to find your reply in the message, helping ensure it won't be
> missed by people scrolling through the irrelevant quoted material.
Okay, thanks Mark.
>
> > > No, I mean that the reason the DMA transfer fails may be something
> > > that happens after we've started putting things on the bus - the bit
> > > about FIFOs is just a random example of an error that could happen.
>
> > Sorry Mark for that I can't get your point... The bus error such as
> > data corrupt seems not the spi core's business since it can only be
> > caught in spi controller driver or upper level such as mtd driver
> > (spi-nor) which know what's the failure happen at spi bus HW level or
> > what's the correct data/message. In other words, spi core can't detect such
> error by transfer_one().
>
> If we see an error in transfer_one() it could be from anything, we've no idea
> what happened on the bus - the controller may have got part way through the
> transfer before failing.
Then how about choosing specific error code for such dma not ready case where
nothing went out on the bus neither?
>
> > But despite of that case, do you think this patch is valid for
> > transfer_one() failue in dma and fallback to pio?
>
> No, not unless we know that nothing went out on the bus.
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next prev parent reply other threads:[~2020-06-15 13:35 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-11 12:58 [PATCH v1 RFC 0/2] introduce fallback to pio in spi core Robin Gong
2020-06-11 12:58 ` Robin Gong
2020-06-11 12:58 ` [PATCH v1 RFC 1/2] spi: introduce fallback to pio Robin Gong
2020-06-11 12:58 ` Robin Gong
2020-06-11 13:40 ` Mark Brown
2020-06-11 13:40 ` Mark Brown
2020-06-12 2:18 ` Robin Gong
2020-06-12 2:18 ` Robin Gong
2020-06-12 10:13 ` Mark Brown
2020-06-12 10:13 ` Mark Brown
2020-06-12 13:48 ` Robin Gong
2020-06-12 13:48 ` Robin Gong
2020-06-12 14:16 ` Mark Brown
2020-06-12 14:16 ` Mark Brown
2020-06-14 13:04 ` Robin Gong
2020-06-14 13:04 ` Robin Gong
2020-06-15 7:19 ` Vinod Koul
2020-06-15 7:19 ` Vinod Koul
2020-06-15 8:59 ` Robin Gong
2020-06-15 8:59 ` Robin Gong
2020-06-15 11:25 ` Vinod Koul
2020-06-15 11:25 ` Vinod Koul
2020-06-16 3:05 ` Robin Gong
2020-06-16 3:05 ` Robin Gong
2020-06-15 12:35 ` Mark Brown
2020-06-15 12:35 ` Mark Brown
2020-06-15 13:35 ` Robin Gong [this message]
2020-06-15 13:35 ` Robin Gong
2020-06-15 13:39 ` Mark Brown
2020-06-15 13:39 ` Mark Brown
2020-06-15 14:18 ` Robin Gong
2020-06-15 14:18 ` Robin Gong
2020-06-15 14:36 ` Mark Brown
2020-06-15 14:36 ` Mark Brown
2020-06-15 14:53 ` Robin Gong
2020-06-15 14:53 ` Robin Gong
2020-06-15 14:55 ` Mark Brown
2020-06-15 14:55 ` Mark Brown
2020-06-16 2:03 ` Robin Gong
2020-06-16 2:03 ` Robin Gong
2020-06-16 9:59 ` Mark Brown
2020-06-16 9:59 ` Mark Brown
2020-06-16 10:13 ` Robin Gong
2020-06-16 10:13 ` Robin Gong
2020-06-16 10:26 ` Mark Brown
2020-06-16 10:26 ` Mark Brown
2020-06-16 12:29 ` Robin Gong
2020-06-16 12:29 ` Robin Gong
2020-06-11 12:58 ` [PATCH v1 RFC 2/2] spi: spi-imx: add fallback feature Robin Gong
2020-06-11 12:58 ` Robin Gong
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