From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030228AbVKPIgE (ORCPT ); Wed, 16 Nov 2005 03:36:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030229AbVKPIgE (ORCPT ); Wed, 16 Nov 2005 03:36:04 -0500 Received: from smtp8.clb.oleane.net ([213.56.31.28]:52666 "EHLO smtp8.clb.oleane.net") by vger.kernel.org with ESMTP id S1030228AbVKPIgB (ORCPT ); Wed, 16 Nov 2005 03:36:01 -0500 Message-ID: <437AEF61.1030704@aie-etudes.com> Date: Wed, 16 Nov 2005 09:35:45 +0100 From: sej User-Agent: Mozilla Thunderbird 1.0.6 (Windows/20050716) X-Accept-Language: fr, en MIME-Version: 1.0 To: Arjan van de Ven CC: linux-kernel@vger.kernel.org Subject: Re: DMA transfer with kiobuf, kernel 2.4.21 References: <437A1D6E.4060302@aie-etudes.com> <1132076986.2822.34.camel@laptopd505.fenrus.org> <437A20AA.8020001@aie-etudes.com> <1132077714.2822.36.camel@laptopd505.fenrus.org> In-Reply-To: <1132077714.2822.36.camel@laptopd505.fenrus.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi, thank you for your help. I will read the DMA documentation. But I need to make DMA on User memory space allocated in user space. Because I don't want the kernel to make allocation and deallocation during execution for stability. Best regards. Sebastien Arjan van de Ven wrote : >On Tue, 2005-11-15 at 18:53 +0100, sej wrote: > > >>>that sounds the wrong approach.. why don't you make your device driver >>>export an mmap function.. and let the userspace app use that ? >>> >>> >>I can't because I need to allocate 128MB of memory per PCI card and if I put for example 4 cards, I'll have 512MB in kernel memory, and I think there will be some problem in kernel. >> >> > >no there isn't.. there is no rule that memory you allocate for this as >to be lowmem... at all. > > > >> >> >> >>>transfer->Descript[i].size = PAGE_SIZE; >>>transfer->Descript[i].pciaddr = (ULONG) >>>virt_to_phys(page_address(iobuf->maplist[idxIobuf])); >>> >>> >>> >>> >>>you really need to use the PCI DMA mapping api! >>> >>> >>I have a plx bridge PCI9656 with a DMA controler. So I have to make a >>descriptor table with physical address and size. >>I work in 32 bits address mode, but I don't know which function to call >>to get a 36bits address for my controler. >> >> > >see the PCI DMA mapping api. the docs for it are in Documentation/ > > > >- >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/ > > > >