Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932292AbWLQSQs (ORCPT ); Sun, 17 Dec 2006 13:16:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932293AbWLQSQs (ORCPT ); Sun, 17 Dec 2006 13:16:48 -0500 Received: from www.osadl.org ([213.239.205.134]:50672 "EHLO mail.tglx.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932292AbWLQSQs (ORCPT ); Sun, 17 Dec 2006 13:16:48 -0500 From: =?iso-8859-1?q?Hans-J=FCrgen_Koch?= Organization: Linutronix To: Gleb Natapov Subject: Re: uio and DMA memory allocations Date: Sun, 17 Dec 2006 19:16:42 +0100 User-Agent: KMail/1.9.4 Cc: linux-kernel@vger.kernel.org References: <20061217150445.GC11360@minantech.com> In-Reply-To: <20061217150445.GC11360@minantech.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200612171916.43534.hjk@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1031 Lines: 24 Am Sonntag, 17. Dezember 2006 16:04 schrieb Gleb Natapov: > Hi Hans, > > Will it be possible to allocate DMAable memory using uio > framework (currently it isn't as far as I see). More specifically > if a driver needs memory allocated with dma_alloc_coherent() will > it be possible to allocate it and map into userspace using uio? Hi Gleb, I didn't write such a driver yet, but it is certainly possible. As a first thought, I think we need a small change in the uio framework mmap routine. AFAIK, dma_alloc_coherent() returns a kernel virtual address that would not be handled properly by the existing code. At the moment, we only have the choice between logical and physical memory, we probably have to add virtual memory, too. Thanks for that hint, I'll keep it in mind. Hans - 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/