From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 65BD3C4167B for ; Wed, 21 Dec 2022 16:28:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234450AbiLUQ2p (ORCPT ); Wed, 21 Dec 2022 11:28:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229601AbiLUQ2l (ORCPT ); Wed, 21 Dec 2022 11:28:41 -0500 Received: from mx07-00178001.pphosted.com (mx08-00178001.pphosted.com [91.207.212.93]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8FD48FE0; Wed, 21 Dec 2022 08:28:39 -0800 (PST) Received: from pps.filterd (m0046661.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 2BLDfZGx026717; Wed, 21 Dec 2022 17:28:25 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=selector1; bh=sNPTUX0Ovz3Baiyfym3JWn6ZKIPsPnF6LrREPH/9axI=; b=2m9RuS6HDaJ447ZUWJt1zYlBPCmzdVBVM5meqXqZHORSTfksG3dNwhceOb9RZ96qC8cf hhNvqg/w/nGDT5B94+e5z2VzVOTvtzrPm7hkSStZBSJFRM1XEe/5eN3c/m/tEionzF71 WHIWJORjMImMLGBoPw8kIgU3NvyWAifNFAJ5LSyNV+GnZ4kxPzzvlLdy8TGXg4JsYOom /BhKJJeKcfF79gm+lKUFNAN+0snDn2Iksr4Xic2wgtm/6x1hiCJzdjjpNs9fnRfczvl7 ErJbw009xokLUlmeAEWXuT2OB4Q7T/RqokXGTw2cLtRyydvR+peyc8ky1co/2QEyaMs2 LA== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com (PPS) with ESMTPS id 3mka9xaasx-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 21 Dec 2022 17:28:25 +0100 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 019AF100034; Wed, 21 Dec 2022 17:28:20 +0100 (CET) Received: from Webmail-eu.st.com (shfdag1node2.st.com [10.75.129.70]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id EE76C233007; Wed, 21 Dec 2022 17:28:19 +0100 (CET) Received: from [10.201.20.73] (10.201.20.73) by SHFDAG1NODE2.st.com (10.75.129.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.13; Wed, 21 Dec 2022 17:28:16 +0100 Message-ID: <12f53ff1-a358-7129-c9ed-9b9fd7dad7e7@foss.st.com> Date: Wed, 21 Dec 2022 17:28:16 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH V4 3/3] rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support Content-Language: en-US To: Sarannya S , , , , CC: , , , Deepak Kumar Singh , Bjorn Andersson References: <1670418258-11502-1-git-send-email-quic_sarannya@quicinc.com> <1670418258-11502-4-git-send-email-quic_sarannya@quicinc.com> From: Arnaud POULIQUEN Organization: STMicroelectronics In-Reply-To: <1670418258-11502-4-git-send-email-quic_sarannya@quicinc.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.201.20.73] X-ClientProxiedBy: EQNCAS1NODE3.st.com (10.75.129.80) To SHFDAG1NODE2.st.com (10.75.129.70) X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.923,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-12-21_09,2022-12-21_01,2022-06-22_01 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/7/22 14:04, Sarannya S wrote: > Add TICOMGET and TIOCMSET ioctl support for rpmsg char device nodes > to get/set the low level transport signals. > > Signed-off-by: Chris Lew > Signed-off-by: Deepak Kumar Singh > Signed-off-by: Sarannya S > --- > drivers/rpmsg/rpmsg_char.c | 60 +++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 52 insertions(+), 8 deletions(-) > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > index 3e0b8f3..8109d18 100644 > --- a/drivers/rpmsg/rpmsg_char.c > +++ b/drivers/rpmsg/rpmsg_char.c > @@ -23,6 +23,7 @@ > #include > #include > #include > +#include > #include > #include > > @@ -68,6 +69,8 @@ struct rpmsg_eptdev { > struct sk_buff_head queue; > wait_queue_head_t readq; > > + u32 remote_signals; > + bool signals_pending; Could you detail the need/use of signals_pending, in your implementation? This is not obvious (at least for me)... > }; > > int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) > @@ -109,7 +112,22 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len, > skb_queue_tail(&eptdev->queue, skb); > spin_unlock(&eptdev->queue_lock); > > - /* wake up any blocking processes, waiting for new data */ > + wake_up_interruptible(&eptdev->readq); > + > + return 0; > +} > + > +static int rpmsg_ept_flow_cb(struct rpmsg_device *rpdev, void *priv, bool enable) > +{ > + struct rpmsg_eptdev *eptdev = priv; > + > + if (enable) > + eptdev->remote_signals = TIOCM_DSR | TIOCM_CTS; > + else > + eptdev->remote_signals = 0; > + > + eptdev->signals_pending = true; > + > wake_up_interruptible(&eptdev->readq); > > return 0; > @@ -146,6 +164,7 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp) > return -EINVAL; > } > > + ept->flow_cb = rpmsg_ept_flow_cb; > eptdev->ept = ept; > filp->private_data = eptdev; > mutex_unlock(&eptdev->ept_lock); > @@ -166,6 +185,7 @@ static int rpmsg_eptdev_release(struct inode *inode, struct file *filp) > eptdev->ept = NULL; > } > mutex_unlock(&eptdev->ept_lock); > + eptdev->signals_pending = false; > > /* Discard all SKBs */ > skb_queue_purge(&eptdev->queue); > @@ -279,6 +299,9 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait) > if (!skb_queue_empty(&eptdev->queue)) > mask |= EPOLLIN | EPOLLRDNORM; > > + if (eptdev->signals_pending) > + mask |= EPOLLPRI; > + > mask |= rpmsg_poll(eptdev->ept, filp, wait); > > return mask; > @@ -289,14 +312,35 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd, > { > struct rpmsg_eptdev *eptdev = fp->private_data; > > - if (cmd != RPMSG_DESTROY_EPT_IOCTL) > - return -EINVAL; > - > - /* Don't allow to destroy a default endpoint. */ > - if (eptdev->default_ept) > - return -EINVAL; > + bool set; > + u32 val; > + int ret; > + > + switch (cmd) { > + case TIOCMGET: > + eptdev->signals_pending = false; > + ret = put_user(eptdev->remote_signals, (int __user *)arg); > + break; > + case TIOCMSET: > + ret = get_user(val, (int __user *)arg); > + if (ret) > + break; > + set = (val & (TIOCM_DTR | TIOCM_RTS)) ? true : false; > + ret = rpmsg_set_flow_control(eptdev->ept, set, 0); > + break; I still wonder if it makes sense to implement serial IOCTRL in rpmsg_char. I think it is quite dangerous to have such kind of mixed interface. User application would want to use the serial interface should use the tty interface. For the rpmsg char, I would be in favor of creating a specific RPMSG IOCTRLs to avoid confusion. For instance: - RPMSG_GET_SIGN_IOCTRL - RPMSG_SET_SIGN_IOCTRL With associated parameter corresponding to the bitmap proposed in my comment of your patch 1/4. Of course, this is only a suggestion, I let Bjorn and Mathieu comment. Regards, Arnaud > + case RPMSG_DESTROY_EPT_IOCTL: > + /* Don't allow to destroy a default endpoint. */ > + if (eptdev->default_ept) { > + ret = -EINVAL; > + break; > + } > + ret = rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL); > + break; > + default: > + ret = -EINVAL; > + } > > - return rpmsg_chrdev_eptdev_destroy(&eptdev->dev, NULL); > + return ret; > } > > static const struct file_operations rpmsg_eptdev_fops = {