From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailrelay005.isp.belgacom.be ([195.238.6.171]) by bombadil.infradead.org with esmtp (Exim 4.68 #1 (Red Hat Linux)) id 1JYjaN-0006ps-8A for linux-mtd@lists.infradead.org; Mon, 10 Mar 2008 15:06:43 +0000 From: Laurent Pinchart To: linuxppc-dev@ozlabs.org Subject: OF compatible MTD platform RAM driver ? Date: Mon, 10 Mar 2008 16:06:31 +0100 MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1451589.TJpG23SlHl"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200803101606.39184.laurentp@cse-semaphore.com> Cc: ben@simtec.co.uk, linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --nextPart1451589.TJpG23SlHl Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hi everybody, as part of a ARCH=3Dppc to ARCH=3Dpowerpc migration process, I'm looking fo= r an=20 OpenFirmware compatible way to handle a RAM-based MTD device. On the platform_device based ppc architecture, the drivers/mtd/maps/plat-ra= m.c=20 driver handled "mtd-ram" platform devices. There is no such driver for the= =20 OF-based powerpc architecture. As a temporary workaround I hacked the physmap_of driver to=20 handle "direct-mapped" OF devices oh type "ram" by adding a corresponding=20 entry in the of_flash_match[] array. This seems to work fine. What would be the preferred way to handle OF-compatible RAM-based MTD=20 devices ? The 3 ways I can think of are 1. porting the plat-ram driver to OF (the driver isn't used in the kernel t= ree=20 but I suspect it is used by out-of-tree boards) 2. creating a new plat-ram-of driver, much like the physmap_of driver comes= =20 from the physmap driver 3. extending the physmap_of driver to handle RAM devices (in which case=20 references to "flash" in the function names should probably be replaced=20 by "mtd") I live option 3 better so far. Has anyone already worked on this ? Is there any defined device tree mappin= g=20 for MTD RAM devices ? Best regards, =2D-=20 Laurent Pinchart CSE Semaphore Belgium Chauss=E9e de Bruxelles, 732A B-1410 Waterloo Belgium T +32 (2) 387 42 59 =46 +32 (2) 387 42 75 --nextPart1451589.TJpG23SlHl Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) iD8DBQBH1U5/8y9gWxC9vpcRAiHPAKC5fQMqWimjqFGVVqNX8hV+C+vhMgCdF5cf hQ26RPBmjf9fBrvQHMkgQio= =yPVj -----END PGP SIGNATURE----- --nextPart1451589.TJpG23SlHl--