Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757071Ab2BHNaP (ORCPT ); Wed, 8 Feb 2012 08:30:15 -0500 Received: from mailout3.w1.samsung.com ([210.118.77.13]:44543 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751789Ab2BHNaN (ORCPT ); Wed, 8 Feb 2012 08:30:13 -0500 MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=us-ascii Date: Wed, 08 Feb 2012 14:30:02 +0100 From: Marek Szyprowski Subject: RE: CMA on arm from zero address In-reply-to: <4F3276D6.3060507@monstr.eu> To: monstr@monstr.eu, "'Russell King - ARM Linux'" Cc: "'Kyungmin Park'" , "'Ohad Ben-Cohen'" , "'LKML'" , linux-arm-kernel@lists.arm.linux.org.uk Message-id: <000c01cce665$c3394ee0$49abeca0$%szyprowski@samsung.com> Organization: SPRC X-Mailer: Microsoft Office Outlook 12.0 Content-language: pl Thread-index: AczmZJSI7spaD98qQoqigM+FBmgeowAAIR6w References: <4F326A4E.1030106@monstr.eu> <20120208130807.GJ889@n2100.arm.linux.org.uk> <4F3276D6.3060507@monstr.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1590 Lines: 42 Hello, On Wednesday, February 08, 2012 2:21 PM Michal Simek wrote: > Russell King - ARM Linux wrote: > > On Wed, Feb 08, 2012 at 01:27:58PM +0100, Michal Simek wrote: > >> Hi, > >> > >> I would like to setup CMA space at the beginning of ram because > >> I want to use remoteproc to run code on the second cpu which has to > >> use addresses 0x0 - 32MB. > >> > >> I have changed textofs in arch/arm/Makefile but there is not possible > >> to setup all values which I would like to use. > > > > What a broken setup. Placing the kernel outside of the 16MB window > > effectively prevents you from using modules. Why do people come up > > with stupid things like this. Please stop. Put such things at the > > end of RAM instead and save the rest of the ARM community from this > > madness. > > First of all I have found how to do it (by CONFIG_PHYS_OFFSET) so the problem is in QEMU. > Currently experimenting how to convince CMA to allocate that memory for my purpose. I'm not sure if CMA is the right allocation api for this purpose. You should better use memblock allocator to grab specific address ranges for your custom setup. Alternatively you can compile Linux kernel to start physical memory at 16MiB and access the 0-16MiB range with ioremap for example. (snipped) Best regards -- Marek Szyprowski Samsung Poland R&D Center -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/