From: Arnd Bergmann <arnd@arndb.de>
To: "Masayuki Ohtake" <masa-korg@dsn.okisemi.com>
Subject: Re: [PATCH] Topcliff PHUB: Generate PacketHub driver
Date: Wed, 16 Jun 2010 12:50:44 +0200
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Cc: "Alan Cox" <alan@lxorguk.ukuu.org.uk>,
       "LKML" <linux-kernel@vger.kernel.org>,
       "Andrew" <andrew.chih.howe.khor@intel.com>,
       "Intel OTC" <joel.clark@intel.com>, "Wang, Qi" <qi.wang@intel.com>,
       "Wang, Yong Y" <yong.y.wang@intel.com>
References: <001401cb0c58$33b3ae20$66f8800a@maildom.okisemi.com> <201006151237.30698.arnd@arndb.de> <000801cb0d32$24ca1360$66f8800a@maildom.okisemi.com>
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On Wednesday 16 June 2010, Masayuki Ohtake wrote:
> > Especially if you want to be able to use tools like 'cat', 'hexdump'
> > or 'dd' on the file descriptor, you need to implement support for
> > short reads.
> I don't know how to test(short read/write access).
> Could you tell me how to do the above ?

The easiest way is using dd, where you can specify the block
size as well as input and output offsets.

e.g.
dd if=/dev/topcliffphub of=testfile bs=7

Should be able to read the contents of the rom completely
without error conditions, copying seven bytes at a time.

dd if=inputfile of=/dev/topcliffphub bs=1 seek=1024 count=16

would write 16 bytes from inputfile into the rom at position 1024.

	Arnd
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