From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755239AbcHVN1N (ORCPT ); Mon, 22 Aug 2016 09:27:13 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:60022 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752859AbcHVN1M (ORCPT ); Mon, 22 Aug 2016 09:27:12 -0400 Subject: Re: [PATCH] dmaengine: qcom_hidma: release the descriptor before the callback To: Vinod Koul References: <20160810172805.GH9681@localhost> <20160819024853.GR9681@localhost> <8c096fee-9749-a7df-7e04-25d21c0ea9ac@codeaurora.org> <20160819034249.GS9681@localhost> <3592cfe2-a563-7c26-9a9e-925051cc1934@codeaurora.org> <20160819055252.GT9681@localhost> <37b059dcb67d1c83c2193acecef0ab96@codeaurora.org> <20160819170208.GC9343@localhost> <20160822060803.GH2890@localhost> Cc: Russell King - ARM Linux , linux-arm-msm@vger.kernel.org, timur@codeaurora.org, linux-kernel@vger.kernel.org, Christopher Covington , dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org From: Sinan Kaya Message-ID: <6151fe21-3c48-e691-1c99-bafd3cc699e6@codeaurora.org> Date: Mon, 22 Aug 2016 09:27:04 -0400 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20160822060803.GH2890@localhost> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/22/2016 2:08 AM, Vinod Koul wrote: > On Fri, Aug 19, 2016 at 01:21:34PM -0400, Sinan Kaya wrote: >> On 8/19/2016 1:02 PM, Vinod Koul wrote: >>> On Fri, Aug 19, 2016 at 07:13:43AM -0400, okaya@codeaurora.org wrote: >>>> On 2016-08-19 01:52, Vinod Koul wrote: >>>>> On Thu, Aug 18, 2016 at 11:48:52PM -0400, Sinan Kaya wrote: >>>>>> On 8/18/2016 11:42 PM, Vinod Koul wrote: >>>>>>> On Thu, Aug 18, 2016 at 11:26:28PM -0400, Sinan Kaya wrote: >>>>>>>> On 8/18/2016 10:48 PM, Vinod Koul wrote: >>>>>>>>>> Keep a size limited list with error cookies and flush them in terminate all? >>>>>>>>> I think so, terminate_all anyway cleans up the channel. Btw what is the >>>>>>>>> behaviour on error? Do you terminate or somthing else? >>>>>>>>> >>>>>>>> >>>>>>>> On error, I flush all outstanding transactions with an error code and I reset >>>>>>>> the channel. After the reset, the DMA channel is functional again. The client >>>>>>>> doesn't need to shutdown anything. >>>>>>> >>>>>>> You mean from the client context or driver? >>>>>>> >>>>>> >>>>>> The client doesn't need to call device_free_chan_resources and >>>>>> device_terminate_all >>>>>> to be specific. Client can certainly call these if it needs to >>>>>> but it is not >>>>>> required to recover the channel. >>>>> >>>>> You didn't answer my question! >>>>> >>>>> On error you said you flush, so who does that? >>>> >>>> This is done by the driver in interrupt context when an error >>>> interrupt is received. All transactions are posted and hw is reset. >>> >>> Hmmm, waht about the txn which are pending? DO you clear them..? >>> >> >> Yes, I clear both pending and active transactions. > > Okay, in that case your can consider below: > > 1. dmaengine asserts error interrupt > 2. Driver receives and mark's the txn as error > 3. Driver completes the txn and intimates the client. No further > submissions. Drop the locks before calling callback, as subsequent > processing by client maybe in callback thread. > 4. Client invokes status and you can return error > 5. On error, client calls terminate_all. You can reset channel, free all > descriptors in the active, pending and completed lists > 6. Client prepares new txn and so on.. Just to be clear, you are telling me not to accept any new transactions until terminate_all is called, right? > > Thanks > -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.