From: Wolfram Sang <wsa@the-dreams.de>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: linux-i2c@vger.kernel.org, linux-sh@vger.kernel.org,
Magnus Damm <magnus.damm@gmail.com>,
Simon Horman <horms@verge.net.au>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Kuninori Morimoto <kuninori.morimoto.gx@gmail.com>,
Yoshihiro Kaneko <ykaneko0929@gmail.com>,
Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Subject: Re: [PATCH 0/9] i2c: rcar: tackle race conditions in the driver
Date: Thu, 3 Sep 2015 22:55:59 +0200 [thread overview]
Message-ID: <20150903205558.GC1574@katana> (raw)
In-Reply-To: <3091262.bFRErFxuqq@avalon>
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> I meant without polling. Does the hardware design prevent from using I2C in
> interrupt mode in a race-free way ?
Yes, when we get a NACK after address phase. HW automatically creates a
STOP condition after a NACK. After this STOP, if we haven't been fast
enough to clear the ESG bit (which started the address phase), then it
will be still set and a new message will be created.
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WARNING: multiple messages have this Message-ID (diff)
From: Wolfram Sang <wsa@the-dreams.de>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: linux-i2c@vger.kernel.org, linux-sh@vger.kernel.org,
Magnus Damm <magnus.damm@gmail.com>,
Simon Horman <horms@verge.net.au>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Kuninori Morimoto <kuninori.morimoto.gx@gmail.com>,
Yoshihiro Kaneko <ykaneko0929@gmail.com>,
Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Subject: Re: [PATCH 0/9] i2c: rcar: tackle race conditions in the driver
Date: Thu, 03 Sep 2015 20:55:59 +0000 [thread overview]
Message-ID: <20150903205558.GC1574@katana> (raw)
In-Reply-To: <3091262.bFRErFxuqq@avalon>
[-- Attachment #1: Type: text/plain, Size: 395 bytes --]
> I meant without polling. Does the hardware design prevent from using I2C in
> interrupt mode in a race-free way ?
Yes, when we get a NACK after address phase. HW automatically creates a
STOP condition after a NACK. After this STOP, if we haven't been fast
enough to clear the ESG bit (which started the address phase), then it
will be still set and a new message will be created.
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[-- Type: application/pgp-signature, Size: 819 bytes --]
next prev parent reply other threads:[~2015-09-03 20:55 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-03 20:20 [PATCH 0/9] i2c: rcar: tackle race conditions in the driver Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
2015-09-03 20:20 ` [PATCH 1/9] i2c: rcar: rework hw init Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
2015-09-03 20:20 ` [PATCH 2/9] i2c: rcar: remove unused IOERROR state Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
[not found] ` <1441311613-2681-1-git-send-email-wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
2015-09-03 20:20 ` [PATCH 3/9] i2c: rcar: remove spinlock Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
2015-09-03 20:20 ` [PATCH 4/9] i2c: rcar: refactor setup of a msg Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
2015-09-03 20:20 ` [PATCH 5/9] i2c: rcar: init new messages in irq Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
2015-10-21 23:10 ` Laurent Pinchart
2015-10-21 23:10 ` Laurent Pinchart
2015-10-22 11:05 ` Wolfram Sang
2015-10-22 11:05 ` Wolfram Sang
2015-10-22 11:12 ` Laurent Pinchart
2015-10-22 11:12 ` Laurent Pinchart
2015-10-23 8:06 ` Wolfram Sang
2015-10-23 8:06 ` Wolfram Sang
2015-10-23 8:57 ` Laurent Pinchart
2015-10-23 9:45 ` Wolfram Sang
2015-10-23 9:45 ` Wolfram Sang
2015-10-23 10:28 ` Laurent Pinchart
2015-10-23 10:28 ` Laurent Pinchart
2015-10-23 12:14 ` Wolfram Sang
2015-10-23 12:14 ` Wolfram Sang
2015-10-23 13:14 ` Laurent Pinchart
2015-10-23 13:14 ` Laurent Pinchart
2015-10-25 15:53 ` Wolfram Sang
2015-10-25 15:53 ` Wolfram Sang
2015-10-29 19:23 ` Wolfram Sang
2015-10-29 19:23 ` Wolfram Sang
2015-10-23 10:04 ` Geert Uytterhoeven
2015-10-23 10:04 ` Geert Uytterhoeven
2015-10-23 10:07 ` Wolfram Sang
2015-10-23 10:07 ` Wolfram Sang
2015-09-03 20:20 ` [PATCH 7/9] i2c: rcar: check master irqs before slave irqs Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
2015-09-03 20:20 ` [PATCH 6/9] i2c: rcar: don't issue stop when HW does it automatically Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
2015-09-03 20:20 ` [PATCH 8/9] i2c: rcar: revoke START request early Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
2015-09-03 20:20 ` [PATCH 9/9] i2c: rcar: clean up after refactoring Wolfram Sang
2015-09-03 20:20 ` Wolfram Sang
2015-09-03 20:35 ` [PATCH 0/9] i2c: rcar: tackle race conditions in the driver Laurent Pinchart
2015-09-03 20:35 ` Laurent Pinchart
2015-09-03 20:40 ` Wolfram Sang
2015-09-03 20:40 ` Wolfram Sang
2015-09-03 20:47 ` Laurent Pinchart
2015-09-03 20:47 ` Laurent Pinchart
2015-09-03 20:55 ` Wolfram Sang [this message]
2015-09-03 20:55 ` Wolfram Sang
2015-09-04 4:33 ` Magnus Damm
2015-09-04 4:33 ` Magnus Damm
2015-09-05 7:31 ` Wolfram Sang
2015-09-05 7:31 ` Wolfram Sang
2015-09-07 16:04 ` Magnus Damm
2015-09-07 16:04 ` Magnus Damm
[not found] ` <CANqRtoRs=f=07B=HSLCVg5G4rnhxj6Heod+spYwxHiKFLZqFWg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-09-08 10:53 ` Wolfram Sang
2015-09-08 10:53 ` Wolfram Sang
2015-09-09 5:08 ` Magnus Damm
2015-09-09 5:08 ` Magnus Damm
2015-09-09 8:54 ` Wolfram Sang
2015-09-09 8:54 ` Wolfram Sang
2015-10-09 21:34 ` Wolfram Sang
2015-10-09 21:34 ` Wolfram Sang
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