Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753906AbZGVNfS (ORCPT ); Wed, 22 Jul 2009 09:35:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752885AbZGVNfR (ORCPT ); Wed, 22 Jul 2009 09:35:17 -0400 Received: from mga01.intel.com ([192.55.52.88]:24890 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752833AbZGVNfQ convert rfc822-to-8bit (ORCPT ); Wed, 22 Jul 2009 09:35:16 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.43,247,1246863600"; d="scan'208";a="477032194" From: "Sosnowski, Maciej" To: Nicolas Ferre CC: "Williams, Dan J" , "linux-arm-kernel@lists.arm.linux.org.uk" , "linux-kernel@vger.kernel.org" , "avictor.za@gmail.com" , "patrice.vilchez@atmel.com" Date: Wed, 22 Jul 2009 14:35:06 +0100 Subject: RE: [PATCH 1/2 v3] dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller Thread-Topic: [PATCH 1/2 v3] dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller Thread-Index: AcoJ3iePonWDKRNUQU6muKrjWbMDmgA7X5oQ Message-ID: <129600E5E5FB004392DDC3FB599660D7AF6D5C9A@irsmsx504.ger.corp.intel.com> References: <1246012936-10812-1-git-send-email-nicolas.ferre@atmel.com> <1246641873-21686-1-git-send-email-nicolas.ferre@atmel.com> <4A657D58.2060708@atmel.com> In-Reply-To: <4A657D58.2060708@atmel.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2347 Lines: 55 Nicolas Ferre wrote: > Dan Williams : >> On Fri, Jul 3, 2009 at 10:24 AM, Nicolas Ferre wrote: >>> This AHB DMA Controller (aka HDMA or DMAC on AT91 systems) is availlable on >>> at91sam9rl chip. It will be used on other products in the future. >>> >>> This first release covers only the memory-to-memory tranfer type. This is the >>> only tranfer type supported by this chip. On other products, it will be used >>> also for peripheral DMA transfer (slave API support to come). >>> >>> I used dmatest client without problem in different configurations to test it. >>> >>> Full documentation for this controller can be found in the SAM9RL datasheet: >>> http://www.atmel.com/dyn/products/product_card.asp?part_id=4243 >>> >>> Signed-off-by: Nicolas Ferre --- >>> v2 is here: >>> http://lkml.org/lkml/2009/6/26/104 >>> >>> v2 -> v3: >>> - initial number of descriptors to allocate for each channel raised to 64 and is now a >>> parameter >>> - ack-bit in descriptor flag comment synchronized with TXx9 dma driver >>> - atc_desc_get() when short on descriptors in pool: create one at a time >>> - allocation flag changed to GFP_ATOMIC in atc_desc_get() >>> - call to proper funtion while unmapping: use of new >>> DMA_COMPL_{SRC,DEST}_UNMAP_SINGLE flags >>> - call dma_run_dependencies() at the end of atc_chain_complete() >>> >> >> Looks good, but now I belatedly wonder if that GFP_ATOMIC should be >> GFP_NOWAIT instead? Do we really want to consume from the system >> emergency pools for these allocations (a similar fix is need for >> ioatdma and fsldma)? > > Seems sensible indeed but I know little about allocation flags. > > What do you think about including the driver and then building a patch > that fixes this flag in all allocation functions at a time. > It may add exposure to this modification and maybe encourage people to > react... I think it's a good plan. I will prepare similar patch on allocation flags for ioatdma. For this v3 patch: Acked-by: Maciej Sosnowski Regards, Maciej-- 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/