Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750990AbdFOFOy (ORCPT ); Thu, 15 Jun 2017 01:14:54 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:45834 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750774AbdFOFOu (ORCPT ); Thu, 15 Jun 2017 01:14:50 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 00D6260316 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=sricharan@codeaurora.org Subject: Re: [PATCH 07/18] spi: qup: Fix transaction done signaling To: Andy Gross Cc: Varadarajan Narayanan , broonie@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com, david.brown@linaro.org, linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org References: <1497419551-21834-1-git-send-email-varada@codeaurora.org> <1497419551-21834-8-git-send-email-varada@codeaurora.org> <4b81a4c7-b85c-a35d-15fb-4aaaec3c7e8c@codeaurora.org> <20170614195155.GB32733@hector.wework.com> From: Sricharan R Message-ID: <83e60e35-747f-4427-b77c-5dda653432ae@codeaurora.org> Date: Thu, 15 Jun 2017 10:44:43 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <20170614195155.GB32733@hector.wework.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1956 Lines: 50 Hi Andy, On 6/15/2017 1:21 AM, Andy Gross wrote: > On Wed, Jun 14, 2017 at 12:43:43PM +0530, Sricharan R wrote: >> Hi Varada, >> >> On 6/14/2017 11:22 AM, Varadarajan Narayanan wrote: >>> Wait to signal done until we get all of the interrupts we are expecting >>> to get for a transaction. If we don't wait for the input done flag, we >>> can be inbetween transactions when the done flag comes in and this can >>> mess up the next transaction. >>> >>> Signed-off-by: Andy Gross >>> Signed-off-by: Varadarajan Narayanan >>> --- >>> drivers/spi/spi-qup.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c >>> index 2124815..7c22ee4 100644 >>> --- a/drivers/spi/spi-qup.c >>> +++ b/drivers/spi/spi-qup.c >>> @@ -465,7 +465,8 @@ static irqreturn_t spi_qup_qup_irq(int irq, void *dev_id) >>> controller->xfer = xfer; >>> spin_unlock_irqrestore(&controller->lock, flags); >>> >>> - if (controller->rx_bytes == xfer->len || error) >>> + if ((controller->rx_bytes == xfer->len && >>> + (opflags & QUP_OP_MAX_INPUT_DONE_FLAG)) || error) >> >> Not sure why we need this additional check, because having read all the >> bytes implies transfer complete (or) why not just check only for >> QUP_OP_MAX_INPUT_DONE_FLAG ? > > So you can receive an interrupt for the last data without it having also > signalled the INPUT_DONE. That means you'd have one more IRQ come in and if you > don't wait for that, you could start up the next transaction and have an irq > come in that screws up that transaction. > > It might be sufficient to just wait for the INPUT_DONE_FLAG. That cannot be > signalled unless the rx_bytes == xfer->len. > Right, that should simply it little bit. Regards, Sricharan -- "QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation