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[68.147.0.187]) by smtp.gmail.com with ESMTPSA id pc17sm21713pjb.19.2021.04.21.10.40.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Apr 2021 10:40:55 -0700 (PDT) Date: Wed, 21 Apr 2021 11:40:53 -0600 From: Mathieu Poirier To: Arnaud Pouliquen Cc: Bjorn Andersson , Ohad Ben-Cohen , linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com Subject: Re: [PATCH v2 5/7] rpmsg: char: Introduce a rpmsg driver for the rpmsg char device Message-ID: <20210421174053.GA1223348@xps15> References: <20210413134458.17912-1-arnaud.pouliquen@foss.st.com> <20210413134458.17912-6-arnaud.pouliquen@foss.st.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210413134458.17912-6-arnaud.pouliquen@foss.st.com> Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org 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? > 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 > + .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 >