From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zigzag.lvk.cs.msu.su ([158.250.17.23]) by bombadil.infradead.org with esmtps (Exim 4.68 #1 (Red Hat Linux)) id 1JoNrO-0006TY-4T for linux-mtd@lists.infradead.org; Tue, 22 Apr 2008 19:08:58 +0000 Received: from Debian-exim by zigzag.lvk.cs.msu.su with spam-scanned (Exim 4.63) (envelope-from ) id 1JoNrE-0000Q5-U2 for linux-mtd@lists.infradead.org; Tue, 22 Apr 2008 23:08:52 +0400 From: "Nikita V. Youshchenko" To: David Woodhouse Subject: Re: [PATCH] mtd: support for bit-reversed CFI cmd/query Date: Tue, 22 Apr 2008 23:08:32 +0400 References: <200802272348.13180@blacky.localdomain> <1208890591.9212.654.camel@pmac.infradead.org> In-Reply-To: <1208890591.9212.654.camel@pmac.infradead.org> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1644156.FvyZUbpBte"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200804222308.39071@blacky.localdomain> Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --nextPart1644156.FvyZUbpBte Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline > On Wed, 2008-02-27 at 23:48 +0300, Nikita V. Youshchenko wrote: > > mtd: support for bit-reversed CFI cmd/query > > > > Some embedded boards have flash chips connected with reversed bit > > order. Example for 16-bit width: > > chip D0 is bus D15 > > chip D1 is bus D14 > > ... > > chip D15 is bus D0 > > It works perfectly for data access, however probing and issuing > > CFI commands for such chips require bit reversing. This patch adds > > support for this. > > > > Signed-off-by: Nikita Youshchenko > > Am I missing something, or did you only reverse the bits on 16-bit and > 64-bit access, and not 8-bit or 32-bit? Hmm... Looks so :(. The board I work with has 16-bit flash, so I could not test others. Btw, the vendor of the board confirmed that such a strange flash chip=20 connection is 'an old hardware bug', however they decided to keep it in=20 current and future revisions of the board 'for backward compatibility'. Is it a good idea to support such strange cases in the official kernel? If yes, I may send an updated patch. Nikita --nextPart1644156.FvyZUbpBte Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBIDje3v3x5OskTLdsRApKRAJ44RmkL9Ge43tr2q3PJmckhAID7WACgzWBU upOAcGywtaiECmuH7EIbymo= =TW0/ -----END PGP SIGNATURE----- --nextPart1644156.FvyZUbpBte--