From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752568AbeBSKel (ORCPT ); Mon, 19 Feb 2018 05:34:41 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:42466 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752377AbeBSKej (ORCPT ); Mon, 19 Feb 2018 05:34:39 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 19 Feb 2018 16:04:38 +0530 From: Abhishek Sahu To: Sricharan R Cc: Andy Gross , Wolfram Sang , David Brown , linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 04/12] i2c: qup: schedule EOT and FLUSH tags at the end of transfer In-Reply-To: References: <1517644697-30806-1-git-send-email-absahu@codeaurora.org> <1517644697-30806-5-git-send-email-absahu@codeaurora.org> Message-ID: <1347ec85b53728e3eec771ea78bcbe5f@codeaurora.org> User-Agent: Roundcube Webmail/1.2.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-02-15 20:01, Sricharan R wrote: > Hi Abhishek, > > On 2/3/2018 1:28 PM, Abhishek Sahu wrote: >> A single BAM transfer can have multiple read and write messages. >> The EOT and FLUSH tags should be scheduled at the end of BAM HW >> descriptors. Since the READ and WRITE can be present in any order >> so for some of the cases, these tags are not being written >> correctly. >> >> Signed-off-by: Abhishek Sahu >> --- >> drivers/i2c/busses/i2c-qup.c | 54 >> ++++++++++++++++++++------------------------ >> 1 file changed, 24 insertions(+), 30 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-qup.c >> b/drivers/i2c/busses/i2c-qup.c >> index bb83a2967..6357aff 100644 >> --- a/drivers/i2c/busses/i2c-qup.c >> +++ b/drivers/i2c/busses/i2c-qup.c >> @@ -560,7 +560,7 @@ static int qup_i2c_set_tags_smb(u16 addr, u8 >> *tags, struct qup_i2c_dev *qup, >> } >> >> static int qup_i2c_set_tags(u8 *tags, struct qup_i2c_dev *qup, >> - struct i2c_msg *msg, int is_dma) >> + struct i2c_msg *msg) >> { >> u16 addr = i2c_8bit_addr_from_msg(msg); >> int len = 0; >> @@ -601,11 +601,6 @@ static int qup_i2c_set_tags(u8 *tags, struct >> qup_i2c_dev *qup, >> else >> tags[len++] = data_len; >> >> - if ((msg->flags & I2C_M_RD) && last && is_dma) { >> - tags[len++] = QUP_BAM_INPUT_EOT; >> - tags[len++] = QUP_BAM_FLUSH_STOP; >> - } >> - >> return len; >> } >> >> @@ -614,7 +609,7 @@ static int qup_i2c_issue_xfer_v2(struct >> qup_i2c_dev *qup, struct i2c_msg *msg) >> int data_len = 0, tag_len, index; >> int ret; >> >> - tag_len = qup_i2c_set_tags(qup->blk.tags, qup, msg, 0); >> + tag_len = qup_i2c_set_tags(qup->blk.tags, qup, msg); >> index = msg->len - qup->blk.data_len; >> >> /* only tags are written for read */ >> @@ -710,7 +705,7 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev >> *qup, struct i2c_msg *msg, >> while (qup->blk.pos < blocks) { >> tlen = (i == (blocks - 1)) ? rem : limit; >> tags = &qup->start_tag.start[off + len]; >> - len += qup_i2c_set_tags(tags, qup, msg, 1); >> + len += qup_i2c_set_tags(tags, qup, msg); >> qup->blk.data_len -= tlen; >> >> /* scratch buf to read the start and len tags */ >> @@ -738,17 +733,11 @@ static int qup_i2c_bam_do_xfer(struct >> qup_i2c_dev *qup, struct i2c_msg *msg, >> return ret; >> >> off += len; >> - /* scratch buf to read the BAM EOT and FLUSH tags */ >> - ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++], >> - &qup->brx.tag.start[0], >> - 2, qup, DMA_FROM_DEVICE); >> - if (ret) >> - return ret; >> } else { >> while (qup->blk.pos < blocks) { >> tlen = (i == (blocks - 1)) ? rem : limit; >> tags = &qup->start_tag.start[off + tx_len]; >> - len = qup_i2c_set_tags(tags, qup, msg, 1); >> + len = qup_i2c_set_tags(tags, qup, msg); >> qup->blk.data_len -= tlen; >> >> ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++], >> @@ -768,26 +757,31 @@ static int qup_i2c_bam_do_xfer(struct >> qup_i2c_dev *qup, struct i2c_msg *msg, >> } >> off += tx_len; >> >> - if (idx == (num - 1)) { >> - len = 1; >> - if (rx_buf) { >> - qup->btx.tag.start[0] = >> - QUP_BAM_INPUT_EOT; >> - len++; >> - } >> - qup->btx.tag.start[len - 1] = >> - QUP_BAM_FLUSH_STOP; >> - ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++], >> - &qup->btx.tag.start[0], >> - len, qup, DMA_TO_DEVICE); >> - if (ret) >> - return ret; >> - } >> } >> idx++; >> msg++; >> } > > While here, can you please split above the if, else in to two > separate functions ? > and probably one more function for handling the NACK case down below. > The function > size at the moment is too big. > Sure. Already I split this function into 2 functions in [PATCH 09/12] i2c: qup: fix buffer overflow for multiple msg of maximum xfer len which is making function size smaller. I will check if I can split in more functions. >> >> + /* schedule the EOT and FLUSH I2C tags */ >> + len = 1; >> + if (rx_buf) { >> + qup->btx.tag.start[0] = QUP_BAM_INPUT_EOT; >> + len++; >> + >> + /* scratch buf to read the BAM EOT and FLUSH tags */ >> + ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++], >> + &qup->brx.tag.start[0], >> + 2, qup, DMA_FROM_DEVICE); >> + if (ret) >> + return ret; >> + } >> + >> + qup->btx.tag.start[len - 1] = QUP_BAM_FLUSH_STOP; >> + ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++], &qup->btx.tag.start[0], >> + len, qup, DMA_TO_DEVICE); >> + if (ret) >> + return ret; >> + > > May be you can change the commit to make it explicit to say what is > being > fixed, like "current code is broken when there is sequence of > wr,rd,wr" like that. > Agree on this fix otherwise. > Thanks. I will update the commit message to include the failure case which will give clear idea. Thanks, Abhishek