From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f200.google.com (mail-pf0-f200.google.com [209.85.192.200]) by kanga.kvack.org (Postfix) with ESMTP id 6ADCA6B0033 for ; Fri, 6 Oct 2017 12:07:53 -0400 (EDT) Received: by mail-pf0-f200.google.com with SMTP id e69so35349184pfg.1 for ; Fri, 06 Oct 2017 09:07:53 -0700 (PDT) Received: from relmlie1.idc.renesas.com (relmlor2.renesas.com. [210.160.252.172]) by mx.google.com with ESMTP id u70si1515401pfj.110.2017.10.06.09.07.51 for ; Fri, 06 Oct 2017 09:07:52 -0700 (PDT) From: Chris Brandt Subject: RE: [PATCH v5 0/5] cramfs refresh for embedded usage Date: Fri, 6 Oct 2017 16:07:45 +0000 Message-ID: References: <20171006024531.8885-1-nicolas.pitre@linaro.org> <20171006063919.GA16556@infradead.org> In-Reply-To: <20171006063919.GA16556@infradead.org> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Hellwig , Nicolas Pitre Cc: Alexander Viro , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "linux-embedded@vger.kernel.org" , "linux-kernel@vger.kernel.org" On Friday, October 06, 2017, Christoph Hellwig wrote: > This is still missing a proper API for accessing the file system, > as said before specifying a physical address in the mount command > line is a an absolute non-no. >=20 > Either work with the mtd folks to get the mtd core down to an absolute > minimum suitable for you, or figure out a way to specify fs nodes > through DT or similar. On my system, the QSPI Flash is memory mapped and set up by the boot=20 loader. In order to test the upstream kernel, I use a squashfs image and=20 mtd-rom. So, 0x18000000 is the physical address of flash as it is seen by the=20 CPU. Is there any benefit to doing something similar to this? /* File System */ /* Requires CONFIG_MTD_ROM=3Dy */ qspi@18000000 { compatible =3D "mtd-rom"; probe-type =3D "map_rom"; reg =3D <0x18000000 0x4000000>; /* 64 MB*/ bank-width =3D <4>; device-width =3D <1>; #address-cells =3D <1>; #size-cells =3D <1>; partition@800000 { label =3D"user"; reg =3D <0x0800000 0x800000>; /* 8MB @ 0x18800000 */ read-only; }; }; Of course this basically ioremaps the entire space on probe, but I think what you really want to do is just ioremap pages at a time (maybe..I=20 might not be following your code correctly) Chris -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org