From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Gross Subject: Re: [PATCH] spi: qup: Add DMA capabilities Date: Fri, 27 Jun 2014 13:58:30 -0500 Message-ID: <20140627185830.GB13621@qualcomm.com> References: <1403816781-31008-1-git-send-email-agross@codeaurora.org> <20140627105057.GF23300@sirena.org.uk> <20140627155422.GA13621@qualcomm.com> <20140627162411.GO32514@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20140627162411.GO32514-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Russell King - ARM Linux Cc: Mark Brown , Bjorn Andersson , linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Daniel Sneddon , "Ivan T. Ivanov" , Sagar Dharia , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-arm-msm@vger.kernel.org On Fri, Jun 27, 2014 at 05:24:11PM +0100, Russell King - ARM Linux wrote: > > > It would be better to use the core DMA mapping code rather than open > > > coding. This code won't work for vmalloc()ed addresses, or physically > > > non-contiguous addresses unless there's an IOMMU fixing things up. > > > > Ah, ok. So I just need a to setup the scatter gather page list and then do a > > dma_map_sg. I'll resend once I have this in place. > > Note that DMA from vmalloc'd memory is non-coherent on some platforms, > even if you use the DMA API. Thankfully, that isn't the case on this platform. As as the QUP controller is only on Qualcomm chipsets, we don't have to worry about it being used on other platforms. -- sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752864AbaF0S6e (ORCPT ); Fri, 27 Jun 2014 14:58:34 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:44674 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751273AbaF0S6d (ORCPT ); Fri, 27 Jun 2014 14:58:33 -0400 Date: Fri, 27 Jun 2014 13:58:30 -0500 From: Andy Gross To: Russell King - ARM Linux Cc: Mark Brown , Bjorn Andersson , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, Daniel Sneddon , "Ivan T. Ivanov" , Sagar Dharia , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] spi: qup: Add DMA capabilities Message-ID: <20140627185830.GB13621@qualcomm.com> References: <1403816781-31008-1-git-send-email-agross@codeaurora.org> <20140627105057.GF23300@sirena.org.uk> <20140627155422.GA13621@qualcomm.com> <20140627162411.GO32514@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140627162411.GO32514@n2100.arm.linux.org.uk> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 27, 2014 at 05:24:11PM +0100, Russell King - ARM Linux wrote: > > > It would be better to use the core DMA mapping code rather than open > > > coding. This code won't work for vmalloc()ed addresses, or physically > > > non-contiguous addresses unless there's an IOMMU fixing things up. > > > > Ah, ok. So I just need a to setup the scatter gather page list and then do a > > dma_map_sg. I'll resend once I have this in place. > > Note that DMA from vmalloc'd memory is non-coherent on some platforms, > even if you use the DMA API. Thankfully, that isn't the case on this platform. As as the QUP controller is only on Qualcomm chipsets, we don't have to worry about it being used on other platforms. -- sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation From mboxrd@z Thu Jan 1 00:00:00 1970 From: agross@codeaurora.org (Andy Gross) Date: Fri, 27 Jun 2014 13:58:30 -0500 Subject: [PATCH] spi: qup: Add DMA capabilities In-Reply-To: <20140627162411.GO32514@n2100.arm.linux.org.uk> References: <1403816781-31008-1-git-send-email-agross@codeaurora.org> <20140627105057.GF23300@sirena.org.uk> <20140627155422.GA13621@qualcomm.com> <20140627162411.GO32514@n2100.arm.linux.org.uk> Message-ID: <20140627185830.GB13621@qualcomm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Jun 27, 2014 at 05:24:11PM +0100, Russell King - ARM Linux wrote: > > > It would be better to use the core DMA mapping code rather than open > > > coding. This code won't work for vmalloc()ed addresses, or physically > > > non-contiguous addresses unless there's an IOMMU fixing things up. > > > > Ah, ok. So I just need a to setup the scatter gather page list and then do a > > dma_map_sg. I'll resend once I have this in place. > > Note that DMA from vmalloc'd memory is non-coherent on some platforms, > even if you use the DMA API. Thankfully, that isn't the case on this platform. As as the QUP controller is only on Qualcomm chipsets, we don't have to worry about it being used on other platforms. -- sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation