From: "Girish" <girishsg-l0cyMroinI0@public.gmane.org>
To: "'Ned Forrester'" <nforrester-/d+BM93fTQY@public.gmane.org>,
"'Roger Frøysaa'" <roger-UslnteNVNtIXWF+eFR7m5Q@public.gmane.org>
Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: Status of Linux SPI slave
Date: Tue, 16 Oct 2007 19:51:11 +0530 [thread overview]
Message-ID: <014301c80fff$ceacd710$6a8918ac@ent.ti.com> (raw)
In-Reply-To: <47111665.7000005-/d+BM93fTQY@public.gmane.org>
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 2222 bytes --]
>-----Original Message-----
>Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
>Subject: Re: [spi-devel-general] Status of Linux SPI slave
>
>Roger Frøysaa wrote:
>> Hi.
>>
>
>For example, I have an SPI master device that streams data to a Linux
>processor at 11Mbit/sec, but never expects any response from the
>processor; this data is written over the 100baseT network to an NFS
>file system at an effective 5GBytes/hour. To make it work, I have
>heavily modified the pxa2xx-spi driver for the target Gumstix system so
>that it can accept data driven by an external clock, and so that it uses
>a queue of DMA descriptors to prevent interrupt latency from limiting
>service of the receive FIFO. I did not have to modify a single line of
>code anywhere else in the SPI framework. All other parts of the SPI
>framework, as well as my protocol driver and user-space code, still
>operate as if they were part of an SPI master; they just keep full a
>queue of SPI messages that request buffers to be filled by SPI reads.
>Basically, this is a VERY limited slave function, where the Linux system
>is not in control of the timing, but also there is never any sort of
>query/response between the master and slave.
Well, now I get the minimal use of slave side transfer. As David suggested
of having spi_slave struct wrapping the hardware, have you thought of
something like that and how would your existing pxa2xx-spi driver will be
impacted?
And thanks for starting this thread:).
Actually, in my case I had to modify controller driver to support SPI in
master and slave mode as well, with standard transfers (half/full duplex
communication).
Regards,
Girish
>
>-------------------------------------------------------------------------
>This SF.net email is sponsored by: Splunk Inc.
>Still grepping through log files to find problems? Stop.
>Now Search log events and configuration files using AJAX and a browser.
>Download your FREE copy of Splunk now >> http://get.splunk.com/
>_______________________________________________
>spi-devel-general mailing list
>spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
>https://lists.sourceforge.net/lists/listinfo/spi-devel-general
[-- Attachment #2: Type: text/plain, Size: 314 bytes --]
-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems? Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >> http://get.splunk.com/
[-- Attachment #3: Type: text/plain, Size: 210 bytes --]
_______________________________________________
spi-devel-general mailing list
spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
https://lists.sourceforge.net/lists/listinfo/spi-devel-general
next prev parent reply other threads:[~2007-10-16 14:21 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-27 8:16 Status of Linux SPI slave Roger Frøysaa
2007-10-13 15:47 ` David Brownell
[not found] ` <20071013154747.2F7B023A5F4-ZcXrCSuhvln6VZ3dlLfH/g4gEjPzgfUyLrfjE7I9kuVHxeISYlDBzl6hYfS7NtTn@public.gmane.org>
2007-10-15 15:43 ` Girish
2007-10-15 16:08 ` Girish
[not found] ` <00bc01c80f45$9d218980$6a8918ac-tAZopdYwApTQT0dZR+AlfA@public.gmane.org>
2007-10-16 0:22 ` David Brownell
[not found] ` <20071016002211.6F45E23BCEC-ZcXrCSuhvln6VZ3dlLfH/g4gEjPzgfUyLrfjE7I9kuVHxeISYlDBzl6hYfS7NtTn@public.gmane.org>
2007-10-16 13:50 ` Girish
[not found] ` <014101c80ffb$917d1200$6a8918ac-tAZopdYwApTQT0dZR+AlfA@public.gmane.org>
2007-10-16 17:59 ` David Brownell
[not found] ` <20071016175920.7FA2923BCED-ZcXrCSuhvln6VZ3dlLfH/g4gEjPzgfUyLrfjE7I9kuVHxeISYlDBzl6hYfS7NtTn@public.gmane.org>
2007-10-17 14:00 ` Girish
[not found] ` <01b001c810c6$053fdea0$6a8918ac-tAZopdYwApTQT0dZR+AlfA@public.gmane.org>
2007-10-17 21:36 ` Ned Forrester
2007-10-13 19:03 ` Ned Forrester
[not found] ` <47111665.7000005-/d+BM93fTQY@public.gmane.org>
2007-10-16 14:21 ` Girish [this message]
[not found] ` <014301c80fff$ceacd710$6a8918ac-tAZopdYwApTQT0dZR+AlfA@public.gmane.org>
2007-10-16 17:28 ` Ned Forrester
[not found] ` <4714F4AC.4020402-/d+BM93fTQY@public.gmane.org>
2007-10-17 13:43 ` Girish
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='014301c80fff$ceacd710$6a8918ac@ent.ti.com' \
--to=girishsg-l0cymroini0@public.gmane.org \
--cc=nforrester-/d+BM93fTQY@public.gmane.org \
--cc=roger-UslnteNVNtIXWF+eFR7m5Q@public.gmane.org \
--cc=spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).