From: Ned Forrester <nforrester-/d+BM93fTQY@public.gmane.org>
To: Vernon Sauder <vernoninhand-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: pxa2xx_spi with SFRM
Date: Fri, 29 Aug 2008 23:07:05 -0400 [thread overview]
Message-ID: <48B8B959.5010508@whoi.edu> (raw)
In-Reply-To: <20080829151839.7a85e7d6-W37fpRALFaH6NKmgiXY+hA0JkcsJGQge@public.gmane.org>
With the one small change re: 8191, below, this looks good to go.
For what it's worth, you can add below your sign-off:
Reviewed-by: Ned Forrester <nforrester-/d+BM93fTQY@public.gmane.org>
It's time to add an appropriate [Patch] subject line to the patch, as
outlined in the docs, and email it to David Brownell
<david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>, with CC to the list.
Thanks for pushing this; I know it takes time, and you are right that it
needed to be done.
Vernon Sauder wrote:
> Ned,
>
> Sorry for the slow response. Real world/work intrudes sometimes.
>
> Here is another version of the patch along with responses to your
> comments.
>
> Ned Forrester wrote:
>
>> Vernon Sauder wrote:
>>
>> Also note that the very recent patch that I submitted, tries to address
>> a problem that you encountered with transfer lengths longer than 8192;
>> in that case, I changed the behavior from "fail" to "do it in PIO mode
>> with rate limited warning". Some day the driver could be rewritten to
>> bust long transfers and do the pieces by DMA, but that is too ambitious
>> for now. So you could add to the list of states that transfers longer
>> than 8191 will be PIO. Have you tested that patch to see if it fixes
>> any of your other problems?
>>
>
> I did not try that patch yet. I added a comment to the doc about this.
If you would try that it would be appreciated. I was waiting for your
test to see if it fixed at least one of the MMC problems you were having
(rejected long transfers) before I ask David to push the patch upstream.
--------------------------------
>
> Patch against Linus 2.6 tree after
> 4c246edd2550304df5b766cc841584b2bb058843. It is compile tested only.
>
> ---
> Subject: [PATCH] pxa2xx_spi: Fix chip_info defaults and documentation.
>
> Make the chip info structure data optional by providing reasonable
> defaults. Improve corresponding documentation.
>
> DMA can determine appropriate dma_burst_size and thresholds
> automatically so use DMA even if dma_burst_size is not specified.
>
> Signed-off-by: Vernon Sauder <VernonInHand-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
> Documentation/spi/pxa2xx | 31 ++++++++++++++++++++-----------
> drivers/spi/pxa2xx_spi.c | 43 ++++++++++++++++++++++++++-----------------
> 2 files changed, 46 insertions(+), 28 deletions(-)
>
[snip]
> The following logic is used to determine the type of I/O to be used on
> a per "spi_transfer" basis:
>
> -if !enable_dma or dma_burst_size == 0 then
> +if !enable_dma then
> always use PIO transfers
>
> +if spi_message.len > 8192 then
Oops. if > 8191 (or >=8192), a count of 8192 is not possible in the DMA
controller.
--
Ned Forrester nforrester-/d+BM93fTQY@public.gmane.org
Oceanographic Systems Lab 508-289-2226
Applied Ocean Physics and Engineering Dept.
Woods Hole Oceanographic Institution Woods Hole, MA 02543, USA
http://www.whoi.edu/sbl/liteSite.do?litesiteid=7212
http://www.whoi.edu/hpb/Site.do?id=1532
http://www.whoi.edu/page.do?pid=10079
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next prev parent reply other threads:[~2008-08-30 3:07 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-08 8:02 pxa2xx_spi with SFRM nforrester-/d+BM93fTQY
[not found] ` <1218182539.489bfd8b24a3d-2RFepEojUI3934Ez3d9NBg@public.gmane.org>
2008-08-08 10:08 ` Jonathan Cameron
[not found] ` <489C1B23.6040804-KWPb1pKIrIJaa/9Udqfwiw@public.gmane.org>
2008-08-11 22:55 ` Vernon Sauder
[not found] ` <48A0C35D.5010606-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2008-08-14 15:29 ` Ned Forrester
[not found] ` <48A44F77.1020908-/d+BM93fTQY@public.gmane.org>
2008-08-15 2:44 ` Vernon Sauder
[not found] ` <48A4ED85.1030803-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2008-08-15 19:01 ` Limitations on transfer length [was: pxa2xx_spi with SFRM] Ned Forrester
[not found] ` <48A5D272.1070804-/d+BM93fTQY@public.gmane.org>
2008-09-08 22:42 ` David Brownell
2008-10-24 5:11 ` Vernon Sauder
[not found] ` <490158E8.8060502-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2008-11-13 1:31 ` Ned Forrester
2008-08-15 19:09 ` pxa2xx_spi with SFRM Ned Forrester
[not found] ` <48A5D44D.6040106-/d+BM93fTQY@public.gmane.org>
2008-08-16 2:33 ` Vernon Sauder
[not found] ` <20080815223307.02db86aa-W37fpRALFaH6NKmgiXY+hA0JkcsJGQge@public.gmane.org>
2008-08-18 18:34 ` Ned Forrester
[not found] ` <48A9C0D0.5050304-/d+BM93fTQY@public.gmane.org>
2008-08-20 0:59 ` Ned Forrester
[not found] ` <48AB6C8F.4040408-/d+BM93fTQY@public.gmane.org>
2008-08-21 22:08 ` Vernon Sauder
[not found] ` <20080821180826.491ac70b-W37fpRALFaH6NKmgiXY+hA0JkcsJGQge@public.gmane.org>
2008-08-23 3:23 ` Ned Forrester
[not found] ` <48AF82B3.8040709-/d+BM93fTQY@public.gmane.org>
2008-08-29 19:18 ` Vernon Sauder
[not found] ` <20080829151839.7a85e7d6-W37fpRALFaH6NKmgiXY+hA0JkcsJGQge@public.gmane.org>
2008-08-30 3:07 ` Ned Forrester [this message]
2008-09-08 22:50 ` David Brownell
-- strict thread matches above, loose matches on Subject: below --
2008-08-07 18:03 Vernon Sauder
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