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From: Robert Abel <rabel@cit-ec.uni-bielefeld.de>
To: Tony Lindgren <tony@atomide.com>
Cc: khilman@deeprootsystems.com, linux@arm.linux.org.uk,
	linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] ARM OMAP2+ GPMC: always program GPMCFCLKDIVIDER
Date: Mon, 16 Feb 2015 21:09:11 +0100	[thread overview]
Message-ID: <54E24E67.9060806@cit-ec.uni-bielefeld.de> (raw)
In-Reply-To: <20150216171030.GS2531@atomide.com>

Hi Tony,

On 16 Feb 2015 18:10, Tony Lindgren wrote:
> * Robert ABEL <rabel@cit-ec.uni-bielefeld.de> [150216 07:52]:
>> GPMC uses GPMCFCLKDIVIDER during synchronous as well as asynchronous accesses
>> in conjunction with WAITMONITORINGTIME. Thus, it's wrong to only program it for
>> synchronous accesses. Remove the conditional.
> Do you have some test case that gets fixed by this? Or does this
> fix some regression?
>
> The reason why I'm asking is that AFAIK we've had async access
> working all along?
Maybe to clarify: This is only affects asynchronous accesses with 
WAITREADMONITORING and/or WAITWRITEMONITORING enabled. Regular 
asynchronous accesses without WAIT pin monitoring were never affected to 
begin with and are not affected by this change.

I don't have an off-hand test case and seeing as the current 
implementation is faulty, it's probable nobody actively uses this 
feature. Cf. OMAP35xx TRM (SPRUF98X) pp. 1103. Basically, 
WAITMONITORINGTIME extends the number of cycles from the end of WAIT 
asserted to when the data is provided/sampled and the read/write access 
(should) take place. While this behavior is esoteric, it's not a reason 
not to fix this oversight.

Regards,

Robert

  reply	other threads:[~2015-02-16 20:09 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-16 15:48 [PATCH 0/4] ARM OMAP2+ GPMC: various fixes and bus children Robert ABEL
2015-02-16 15:48 ` [PATCH 1/4] ARM OMAP2+ GPMC: fix debug output alignment Robert ABEL
2015-02-16 15:48   ` [PATCH 2/4] ARM OMAP2+ GPMC: always program GPMCFCLKDIVIDER Robert ABEL
2015-02-16 15:49     ` [PATCH 3/4] ARM OMAP2+ GPMC: fix WAITMONITORINGTIME divider bug Robert ABEL
2015-02-16 15:49       ` [PATCH 4/4] ARM OMAP2+ GPMC: add bus children Robert ABEL
2015-02-17  9:41         ` Roger Quadros
2015-02-17  9:41           ` Roger Quadros
2015-02-17 13:57           ` Robert Abel
2015-02-17 14:15             ` Roger Quadros
2015-02-17 14:15               ` Roger Quadros
2015-02-17  9:27       ` [PATCH 3/4] ARM OMAP2+ GPMC: fix WAITMONITORINGTIME divider bug Roger Quadros
2015-02-17  9:27         ` Roger Quadros
2015-02-17 13:48         ` Robert Abel
2015-02-17 13:56           ` Roger Quadros
2015-02-17 13:56             ` Roger Quadros
2015-02-16 17:10     ` [PATCH 2/4] ARM OMAP2+ GPMC: always program GPMCFCLKDIVIDER Tony Lindgren
2015-02-16 20:09       ` Robert Abel [this message]
2015-02-17  8:12     ` Roger Quadros
2015-02-17  8:12       ` Roger Quadros
2015-02-17 13:47       ` Robert Abel
     [not found]       ` <CAMdRc4F9B0ft-ExgQ1vHqwXMiONwWKn3FPCRDyHsjgGe1Dn_1w@mail.gmail.com>
2015-02-17 13:52         ` Roger Quadros
2015-02-17 13:52           ` Roger Quadros
2015-02-17 14:06           ` Robert Abel
2015-02-17 14:25             ` Roger Quadros
2015-02-17 14:25               ` Roger Quadros
2015-02-23 21:38               ` Robert Abel
2015-02-23 22:03                 ` Tony Lindgren
2015-02-24 11:53                 ` Roger Quadros
2015-02-24 11:53                   ` Roger Quadros

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