From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from az33egw01.freescale.net (az33egw01.freescale.net [192.88.158.102]) by ozlabs.org (Postfix) with ESMTP id 9183167B69 for ; Fri, 1 Jul 2005 01:30:41 +1000 (EST) In-Reply-To: <42C40BD0.8040408@anagramm.de> References: <42C40BD0.8040408@anagramm.de> Mime-Version: 1.0 (Apple Message framework v730) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <658739DB-540F-4AFC-80DC-BBF0C2AD70F4@freescale.com> From: Kumar Gala Date: Thu, 30 Jun 2005 10:30:41 -0500 To: "Clemens Koller" Cc: linuxppc-embedded@ozlabs.org Subject: Re: MPC85xx DMA support for Kernel 2.6? List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Jun 30, 2005, at 10:12 AM, Clemens Koller wrote: > Hello! > > I am planning to use DMA/burst access for copying large chunks of data > (100MBytes) from the Local Bus (UPM accessed SRAM) to System Memory > (DDR) > as fast as possible (200MBytes/s). (As you can guess, that's a > framegrabber). > > As far as I have seen, the DMA engines of the MPC85xx (fsl-dma) are > not > supported in the classical way (dma_request(), free_dma()) in the > kernel 2.6.x. > The memory allocators in arch/ppc/dma-mapping.c seem to be usable, > but there is no valuable dma support yet (true?). > > I can program the DMA Controllers in my MPC8540 on my own to > achieve what I want > but it would be great to get/produce/stick with as much cross- > platform reusable > code as possible. > > Is there any ongoing work to put DMA support for the mpc85xx and > similar > devices into the kernel? Is there any ongoing work in this area > or is somebody working with the fsl-dma and can publish some code and > share some ideas? I'm not aware of anyone work on such a thing. I'd be more than happy to accept patches for it. I know several of us have written some APIs on top of the DMA for 85xx. Those however are non-standard APIs. What APIs exist for general purpose DMA engines? Last time I looked at this problem nothing really existed. - kumar