Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751447AbdH1Lqr (ORCPT ); Mon, 28 Aug 2017 07:46:47 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:44954 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750866AbdH1Lqp (ORCPT ); Mon, 28 Aug 2017 07:46:45 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 3AD576072D 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=aneela@codeaurora.org Subject: Re: [PATCH v2 05/20] rpmsg: glink: Allow unaligned data access To: Sricharan R , ohad@wizery.com, bjorn.andersson@linaro.org, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <1503559302-3744-1-git-send-email-sricharan@codeaurora.org> <1503559302-3744-6-git-send-email-sricharan@codeaurora.org> From: Arun Kumar Neelakantam Message-ID: <6baef774-50ed-2dc9-8aed-5e02b0bfeaa5@codeaurora.org> Date: Mon, 28 Aug 2017 17:16:38 +0530 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <1503559302-3744-6-git-send-email-sricharan@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2982 Lines: 84 On 8/24/2017 12:51 PM, Sricharan R wrote: > From: Bjorn Andersson > > Glink protocol requires that each message is aligned > on a 8 byte offset. This is purely a restriction > from glink, so in order to support clients which > do not adher to this, allow data packets of any size, > but align the head index accordingly, effectively > removing the alignment restriction. > > Signed-off-by: Bjorn Andersson > Signed-off-by: Sricharan R Acked-by: Arun Kumar Neelakantam Regards, Arun N > --- > drivers/rpmsg/qcom_glink_native.c | 6 ------ > drivers/rpmsg/qcom_glink_rpm.c | 22 +++++++++++++++++++++- > 2 files changed, 21 insertions(+), 7 deletions(-) > > diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c > index ffdf88e..a6394cd 100644 > --- a/drivers/rpmsg/qcom_glink_native.c > +++ b/drivers/rpmsg/qcom_glink_native.c > @@ -227,9 +227,6 @@ static int qcom_glink_tx(struct qcom_glink *glink, > if (tlen >= glink->tx_pipe->length) > return -EINVAL; > > - if (WARN(tlen % 8, "Unaligned TX request")) > - return -EINVAL; > - > ret = mutex_lock_interruptible(&glink->tx_lock); > if (ret) > return ret; > @@ -695,9 +692,6 @@ static int __qcom_glink_send(struct glink_channel *channel, > __le32 left_size; > } __packed req; > > - if (WARN(len % 8, "RPM GLINK expects 8 byte aligned messages\n")) > - return -EINVAL; > - > req.msg.cmd = cpu_to_le16(RPM_CMD_TX_DATA); > req.msg.param1 = cpu_to_le16(channel->lcid); > req.msg.param2 = cpu_to_le32(channel->rcid); > diff --git a/drivers/rpmsg/qcom_glink_rpm.c b/drivers/rpmsg/qcom_glink_rpm.c > index 33daa32..cc73af0 100644 > --- a/drivers/rpmsg/qcom_glink_rpm.c > +++ b/drivers/rpmsg/qcom_glink_rpm.c > @@ -156,11 +156,31 @@ static void glink_rpm_tx_write(struct qcom_glink_pipe *glink_pipe, > const void *data, size_t dlen) > { > struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe); > + size_t tlen = hlen + dlen; > + size_t aligned_dlen; > unsigned int head; > + char padding[8] = {0}; > + size_t pad; > + > + /* Header length comes from glink native and is always 4 byte aligned */ > + if (WARN(hlen % 4, "Glink Header length must be 4 bytes aligned\n")) > + return; > + > + /* > + * Move the unaligned tail of the message to the padding chunk, to > + * ensure word aligned accesses > + */ > + aligned_dlen = ALIGN_DOWN(dlen, 4); > + if (aligned_dlen != dlen) > + memcpy(padding, data + aligned_dlen, dlen - aligned_dlen); > > head = readl(pipe->head); > head = glink_rpm_tx_write_one(pipe, head, hdr, hlen); > - head = glink_rpm_tx_write_one(pipe, head, data, dlen); > + head = glink_rpm_tx_write_one(pipe, head, data, aligned_dlen); > + > + pad = ALIGN(tlen, 8) - ALIGN_DOWN(tlen, 4); > + if (pad) > + head = glink_rpm_tx_write_one(pipe, head, padding, pad); > writel(head, pipe->head); > } >