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 X-Spam-Level: X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C4B6C433B4 for ; Thu, 22 Apr 2021 07:58:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6144D61457 for ; Thu, 22 Apr 2021 07:58:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229629AbhDVH7G (ORCPT ); Thu, 22 Apr 2021 03:59:06 -0400 Received: from mx07-00178001.pphosted.com ([185.132.182.106]:36325 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229487AbhDVH7G (ORCPT ); Thu, 22 Apr 2021 03:59:06 -0400 Received: from pps.filterd (m0046668.ppops.net [127.0.0.1]) by mx07-00178001.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13M7vPHl023905; Thu, 22 Apr 2021 09:58:29 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=foss.st.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=selector1; bh=5nCw7851zINOTKX8lPZeKQCd1aIjzhMIwKVs4NjEjx0=; b=Trt2au3lZI8bOVWZkTn4Bu8/Jwg6KiLS+zG/kQngwrSO/nF9Vm/GvLKGdasGpkk2HuXK cignw0wd+tl/0AvByQydPg5kjzvqOb8fWXJxzEBewhBE4fQuODzk2XfN4DyqceW9uxiC rCwbjyDkxeBKjS8MGjjtqX//+jqZaCRHudY5ixQ8n2efE9Xl+FVq6ayOl42VN92kZeO0 3lmsQmzBbwOyxG+dFP25oLuaS0BwI2q6GWFHo6OjFcD0oGKrH+3f1XtK7O0woU4vSJV1 MRAPsFhay/P4n9pDI/k9d1LIt+BVlfk/Q8vZkmgKYv90gi+2yhVvUla1iwn9uyTptaip oA== Received: from beta.dmz-eu.st.com (beta.dmz-eu.st.com [164.129.1.35]) by mx07-00178001.pphosted.com with ESMTP id 382fftetqe-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 22 Apr 2021 09:58:29 +0200 Received: from euls16034.sgp.st.com (euls16034.sgp.st.com [10.75.44.20]) by beta.dmz-eu.st.com (STMicroelectronics) with ESMTP id 4F70410002A; Thu, 22 Apr 2021 09:58:29 +0200 (CEST) Received: from Webmail-eu.st.com (sfhdag2node3.st.com [10.75.127.6]) by euls16034.sgp.st.com (STMicroelectronics) with ESMTP id 417FE221F75; Thu, 22 Apr 2021 09:58:29 +0200 (CEST) Received: from lmecxl0889.lme.st.com (10.75.127.49) by SFHDAG2NODE3.st.com (10.75.127.6) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 22 Apr 2021 09:58:28 +0200 Subject: Re: [PATCH v2 5/7] rpmsg: char: Introduce a rpmsg driver for the rpmsg char device To: Mathieu Poirier CC: Bjorn Andersson , Ohad Ben-Cohen , , , References: <20210413134458.17912-1-arnaud.pouliquen@foss.st.com> <20210413134458.17912-6-arnaud.pouliquen@foss.st.com> <20210421174053.GA1223348@xps15> From: Arnaud POULIQUEN Message-ID: <47015357-b006-1c32-f63f-d4fcac054d6f@foss.st.com> Date: Thu, 22 Apr 2021 09:58:27 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210421174053.GA1223348@xps15> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.75.127.49] X-ClientProxiedBy: SFHDAG2NODE1.st.com (10.75.127.4) To SFHDAG2NODE3.st.com (10.75.127.6) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-22_01:2021-04-21,2021-04-21 signatures=0 Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org On 4/21/21 7:40 PM, Mathieu Poirier wrote: > Good day Arnaud, > > On Tue, Apr 13, 2021 at 03:44:56PM +0200, Arnaud Pouliquen wrote: >> A rpmsg char device allows to probe the endpoint device on a remote name >> service announcement. >> >> With this patch the /dev/rpmsgX interface is created either by a user >> application or by the remote firmware. >> >> Signed-off-by: Arnaud Pouliquen >> >> --- >> update from V1: >> - add missing unregister_rpmsg_driver call on module exit. >> >> --- >> drivers/rpmsg/rpmsg_char.c | 59 +++++++++++++++++++++++++++++++++++++- >> 1 file changed, 58 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c >> index a64249d83172..4606787b7011 100644 >> --- a/drivers/rpmsg/rpmsg_char.c >> +++ b/drivers/rpmsg/rpmsg_char.c >> @@ -26,6 +26,8 @@ >> #include "rpmsg_char.h" >> #include "rpmsg_internal.h" >> >> +#define RPMSG_CHAR_DEVNAME "rpmsg-raw" >> + > > Why not simply call it rpmsg-char? I would avoid to link the rpmsg name service to the Linux Kernel device. > >> static dev_t rpmsg_major; >> >> static DEFINE_IDA(rpmsg_ept_ida); >> @@ -403,13 +405,67 @@ int rpmsg_chrdev_create_eptdev(struct rpmsg_device *rpdev, struct device *parent >> } >> EXPORT_SYMBOL(rpmsg_chrdev_create_eptdev); >> >> +static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) >> +{ >> + struct rpmsg_channel_info chinfo; >> + struct rpmsg_eptdev *eptdev; >> + >> + if (!rpdev->ept) >> + return -EINVAL; >> + >> + memcpy(chinfo.name, RPMSG_CHAR_DEVNAME, sizeof(RPMSG_CHAR_DEVNAME)); >> + chinfo.src = rpdev->src; >> + chinfo.dst = rpdev->dst; >> + >> + eptdev = __rpmsg_chrdev_create_eptdev(rpdev, &rpdev->dev, chinfo, NULL); >> + if (IS_ERR(eptdev)) >> + return PTR_ERR(eptdev); >> + >> + /* Set the private field of the default endpoint to retrieve context on callback. */ >> + rpdev->ept->priv = eptdev; > > This is already done in rpmsg_create_ept() when rpmsg_eptdev_open() is called. > >> + >> + return 0; >> +} >> + >> +static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev) >> +{ >> + int ret; >> + >> + ret = device_for_each_child(&rpdev->dev, NULL, rpmsg_chrdev_destroy_eptdev); >> + if (ret) >> + dev_warn(&rpdev->dev, "failed to destroy endpoints: %d\n", ret); >> +} >> + >> +static struct rpmsg_device_id rpmsg_chrdev_id_table[] = { >> + { .name = RPMSG_CHAR_DEVNAME }, >> + { }, >> +}; >> + >> +static struct rpmsg_driver rpmsg_chrdev_driver = { >> + .probe = rpmsg_chrdev_probe, >> + .remove = rpmsg_chrdev_remove, >> + .id_table = rpmsg_chrdev_id_table, >> + .callback = rpmsg_ept_cb, > > Not sure why we need a callback associated to this driver when > rpmsg_eptdev_open() already creates and rpmsg_endpoint. To me the only thing > having a callback provides is the association between the rpmsg_device and the > rpmsg_endpoint[1] that happens in rpmsg_dev_probe(). The QC folks already do > this association in their platform code[2]. Since this is not done in > __rpmsg_create_ept() a check for rpdev->ept == NULL could be done in > rpmsg_eptdev_open() and do the assignment there. > > [1]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/rpmsg_core.c#L513 > [2]. https://elixir.bootlin.com/linux/v5.12-rc6/source/drivers/rpmsg/qcom_glink_native.c#L1623 > That's a good point! When I started the redesign, I faced some issues with the approach you propose. But as I can not remember the reason and because the code has evolved, i need to re-think about this. Thanks, Arnaud >> + .drv = { >> + .name = "rpmsg_chrdev", >> + }, >> +}; >> + >> static int rpmsg_chrdev_init(void) >> { >> int ret; >> >> ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_char"); >> - if (ret < 0) >> + if (ret < 0) { >> pr_err("rpmsg: failed to allocate char dev region\n"); >> + return ret; >> + } >> + >> + ret = register_rpmsg_driver(&rpmsg_chrdev_driver); >> + if (ret < 0) { >> + pr_err("rpmsg: failed to register rpmsg raw driver\n"); >> + unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX); >> + } >> >> return ret; >> } >> @@ -417,6 +473,7 @@ postcore_initcall(rpmsg_chrdev_init); >> >> static void rpmsg_chrdev_exit(void) >> { >> + unregister_rpmsg_driver(&rpmsg_chrdev_driver); >> unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX); >> } >> module_exit(rpmsg_chrdev_exit); >> -- >> 2.17.1 >>