From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id DD891679E7 for ; Fri, 14 Apr 2006 09:12:31 +1000 (EST) Subject: Re: [patch][rfc]flattened device tree: Passing a dtb (blob) to Linux. From: Benjamin Herrenschmidt To: Jimi Xenidis In-Reply-To: <5148225C-AE27-4365-A1C2-40C46491AF0D@watson.ibm.com> References: <5148225C-AE27-4365-A1C2-40C46491AF0D@watson.ibm.com> Content-Type: text/plain Date: Fri, 14 Apr 2006 09:12:13 +1000 Message-Id: <1144969933.4935.45.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 2006-04-12 at 22:05 -0400, Jimi Xenidis wrote: > A devtree compiler (dtc) generated devtree blob is "relocatable" and > so does not contain a reserved_map entry for the blob itself. > This means that if passed to Linux, Linux will not get lmb_reserve() > the blob and it could be over. > The following patch will explicitly reserve the "blob" as it was > given to us and stops prom_init.c from creating a reserved mapping > for the blob. > > NOTE: that the dtc must also not generate the blob reservation > entry. Should we try to detect this redundant entry? Should we bump > the DT version number? We should make lmb_reserve() of redudant/overlapping entries become harmless I think. We need to be backward compatible with earlier blobs that do contain themselves in the reserve map Ben.