From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH] the eDMA support for the LPUART send driver Date: Tue, 7 Jan 2014 09:53:51 +0100 Message-ID: <201401070953.52207.arnd@arndb.de> References: <1388143449-28640-1-git-send-email-yao.yuan@freescale.com> <20140105145031.GB27432@n2100.arm.linux.org.uk> <0602455564214ab7986348ea985fc820@BL2PR03MB338.namprd03.prod.outlook.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from moutng.kundenserver.de ([212.227.126.187]:57251 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752108AbaAGIyC (ORCPT ); Tue, 7 Jan 2014 03:54:02 -0500 In-Reply-To: <0602455564214ab7986348ea985fc820@BL2PR03MB338.namprd03.prod.outlook.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Yao Yuan Cc: Russell King - ARM Linux , "linux-arm-kernel@lists.infradead.org" , "gregkh@linuxfoundation.org" , "linux-serial@vger.kernel.org" On Tuesday 07 January 2014, Yao Yuan wrote: > Thanks for your suggestion. It's important for me. > > I read the source code for dma_map_single again. I found that both of them(as first argument is > dma or uart) worked well. But in my code I found that the *sport->port.dev->dma_mask is not > zero. By contrast the dma_mask for dma device is zero. Ah, it seems you found two more bugs then ;-) > You are right. There should be dma device. But I also have a doubt here. Why I find many other > driver use the first argument here rather than the dma device pointer. It's a common mistake. Most other linux device driver interfaces require you to pass the device you are working on, so it's understandable why people come to the wrong conclusion here. Arnd From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Tue, 7 Jan 2014 09:53:51 +0100 Subject: [PATCH] the eDMA support for the LPUART send driver In-Reply-To: <0602455564214ab7986348ea985fc820@BL2PR03MB338.namprd03.prod.outlook.com> References: <1388143449-28640-1-git-send-email-yao.yuan@freescale.com> <20140105145031.GB27432@n2100.arm.linux.org.uk> <0602455564214ab7986348ea985fc820@BL2PR03MB338.namprd03.prod.outlook.com> Message-ID: <201401070953.52207.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tuesday 07 January 2014, Yao Yuan wrote: > Thanks for your suggestion. It's important for me. > > I read the source code for dma_map_single again. I found that both of them(as first argument is > dma or uart) worked well. But in my code I found that the *sport->port.dev->dma_mask is not > zero. By contrast the dma_mask for dma device is zero. Ah, it seems you found two more bugs then ;-) > You are right. There should be dma device. But I also have a doubt here. Why I find many other > driver use the first argument here rather than the dma device pointer. It's a common mistake. Most other linux device driver interfaces require you to pass the device you are working on, so it's understandable why people come to the wrong conclusion here. Arnd