From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailrelay005.isp.belgacom.be (mailrelay005.isp.belgacom.be [195.238.6.171]) by ozlabs.org (Postfix) with ESMTP id 8E86BDEB0E for ; Wed, 26 Mar 2008 23:44:36 +1100 (EST) From: Laurent Pinchart To: linux-mtd@lists.infradead.org Subject: [PATCH 2/2] [POWERPC] Describe memory-mapped RAM&ROM chips of bindings MIME-Version: 1.0 Date: Wed, 26 Mar 2008 13:44:26 +0100 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200803261344.26555.laurentp@cse-semaphore.com> Cc: ben@simtec.co.uk, linuxppc-dev@ozlabs.org, David Gibson List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Signed-off-by: Laurent Pinchart =2D-- Documentation/powerpc/booting-without-of.txt | 31 ++++++++++++++++++++++= +++- 1 files changed, 30 insertions(+), 1 deletions(-) diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/p= owerpc/booting-without-of.txt index 7b4e8a7..53d1cf8 100644 =2D-- a/Documentation/powerpc/booting-without-of.txt +++ b/Documentation/powerpc/booting-without-of.txt @@ -57,7 +57,8 @@ Table of Contents n) 4xx/Axon EMAC ethernet nodes o) Xilinx IP cores p) Freescale Synchronous Serial Interface =2D q) USB EHCI controllers + q) USB EHCI controllers + r) Memory-mapped RAM & ROM =20 VII - Specifying interrupt information for devices 1) interrupts property @@ -2816,6 +2817,34 @@ platforms are moved over to use the flattened-device= =2Dtree model. big-endian; }; =20 + r) Memory-mapped RAM & ROM + + Dedicated RAM and ROM chips are often used as storage for temporary or + permanent data in embedded devices. Possible usage include non-volatile + storage in battery-backed SRAM, semi-permanent storage in dedicated SR= AM + to preserve data accross reboots and firmware storage in dedicated ROM. + + - compatible : should contain the specific model of RAM/ROM chip(s) + used, if known, followed by either "physmap-ram" or "physmap-rom" + - reg : Address range of the RAM/ROM chip + - bank-width : Width (in bytes) of the RAM/ROM bank. Equal to the + device width times the number of interleaved chips. + - device-width : (optional) Width of a single RAM/ROM chip. If + omitted, assumed to be equal to 'bank-width'. + + Similarly to memory-mapped NOR flash, memory-mapped RAM & ROM chips + can be partionned. See the "j) CFI and JEDEC memory-mapped NOR flash" + section for information about how to represent partitions in the + device tree. + + Example: + + mmram@f2000000 { + compatible =3D "renesas,m5m5w816", "physmap-ram"; + reg =3D ; + bank-width =3D <2>; + }; + =20 More devices will be defined as this spec matures. =20 =2D-=20 1.5.0 =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