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[68.147.0.187]) by smtp.gmail.com with ESMTPSA id nh21sm9078983pjb.30.2021.12.17.09.15.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Dec 2021 09:15:15 -0800 (PST) Date: Fri, 17 Dec 2021 10:15:13 -0700 From: Mathieu Poirier To: Jay Chen Cc: suzuki.poulose@arm.com, linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, mike.leach@linaro.org, leo.yan@linaro.org, zhangliguang@linux.alibaba.com Subject: Re: [RFC V2 PATCH] coresight: change tmc from misc device to cdev device Message-ID: <20211217171513.GA123267@p14s> References: <20211217034208.64290-1-jkchen@linux.alibaba.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20211217034208.64290-1-jkchen@linux.alibaba.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211217_091518_539078_2D35D8CC X-CRM114-Status: GOOD ( 34.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Good day Jay, On Fri, Dec 17, 2021 at 11:42:08AM +0800, Jay Chen wrote: > From: root > > For coresight in the server scenario, if there are too many > funnel (about 130) and tmc (about 130) peripherals, the error > of insufficient device numbers will occur by misc device > Why is the changelog mention funnels when they have nothing to do with misc devices? > Signed-off-by: root > --- > .../hwtracing/coresight/coresight-tmc-core.c | 84 +++++++++++++++---- > drivers/hwtracing/coresight/coresight-tmc.h | 10 ++- > 2 files changed, 75 insertions(+), 19 deletions(-) > > diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c > index d0276af82494..03b114c0616a 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc-core.c > +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c > @@ -31,6 +31,11 @@ DEFINE_CORESIGHT_DEVLIST(etb_devs, "tmc_etb"); > DEFINE_CORESIGHT_DEVLIST(etf_devs, "tmc_etf"); > DEFINE_CORESIGHT_DEVLIST(etr_devs, "tmc_etr"); > > +static dev_t tmc_major; > +static struct class *tmc_class; > + > +#define TMC_DEV_MAX (MINORMASK + 1) > + > void tmc_wait_for_tmcready(struct tmc_drvdata *drvdata) > { > struct coresight_device *csdev = drvdata->csdev; > @@ -147,7 +152,7 @@ static int tmc_open(struct inode *inode, struct file *file) > { > int ret; > struct tmc_drvdata *drvdata = container_of(file->private_data, > - struct tmc_drvdata, miscdev); > + struct tmc_drvdata, cdev); > > ret = tmc_read_prepare(drvdata); > if (ret) > @@ -179,7 +184,7 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len, > char *bufp; > ssize_t actual; > struct tmc_drvdata *drvdata = container_of(file->private_data, > - struct tmc_drvdata, miscdev); > + struct tmc_drvdata, cdev); > actual = tmc_get_sysfs_trace(drvdata, *ppos, len, &bufp); > if (actual <= 0) > return 0; > @@ -200,7 +205,7 @@ static int tmc_release(struct inode *inode, struct file *file) > { > int ret; > struct tmc_drvdata *drvdata = container_of(file->private_data, > - struct tmc_drvdata, miscdev); > + struct tmc_drvdata, cdev); > > ret = tmc_read_unprepare(drvdata); > if (ret) > @@ -449,8 +454,9 @@ static u32 tmc_etr_get_max_burst_size(struct device *dev) > > static int tmc_probe(struct amba_device *adev, const struct amba_id *id) > { > - int ret = 0; > + int ret = 0, tmc_num = 0; > u32 devid; > + dev_t devt; > void __iomem *base; > struct device *dev = &adev->dev; > struct coresight_platform_data *pdata = NULL; > @@ -546,14 +552,26 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id) > goto out; > } > > - drvdata->miscdev.name = desc.name; > - drvdata->miscdev.minor = MISC_DYNAMIC_MINOR; > - drvdata->miscdev.fops = &tmc_fops; > - ret = misc_register(&drvdata->miscdev); > - if (ret) > + tmc_num = etb_devs.nr_idx + etf_devs.nr_idx + > + etr_devs.nr_idx; Humm... This is turning out to be a lot worse than expected. Please use an IDA, the same way the rpmsg_char driver does. > + > + cdev_init(&drvdata->cdev.cdev, &tmc_fops); > + drvdata->cdev.cdev.owner = THIS_MODULE; > + devt = MKDEV(MAJOR(tmc_major), tmc_num - 1); > + ret = cdev_add(&drvdata->cdev.cdev, devt, 1); > + if (ret) { > coresight_unregister(drvdata->csdev); > - else > + goto out; > + } > + > + drvdata->cdev.dev = device_create(tmc_class, NULL, devt, &drvdata->cdev, desc.name); > + if (IS_ERR(drvdata->cdev.dev)) { > + ret = PTR_ERR(drvdata->cdev.dev); > + cdev_del(&drvdata->cdev.cdev); > + coresight_unregister(drvdata->csdev); > + } else > pm_runtime_put(&adev->dev); > + > out: > return ret; > } > @@ -584,12 +602,8 @@ static void tmc_remove(struct amba_device *adev) > { > struct tmc_drvdata *drvdata = dev_get_drvdata(&adev->dev); > > - /* > - * Since misc_open() holds a refcount on the f_ops, which is > - * etb fops in this case, device is there until last file > - * handler to this device is closed. > - */ > - misc_deregister(&drvdata->miscdev); > + device_destroy(tmc_class, drvdata->cdev.dev->devt); > + cdev_del(&drvdata->cdev.cdev); > coresight_unregister(drvdata->csdev); > } > > @@ -618,7 +632,43 @@ static struct amba_driver tmc_driver = { > .id_table = tmc_ids, > }; > > -module_amba_driver(tmc_driver); > +static int __init tmc_init(void) > +{ > + int ret; > + > + ret = alloc_chrdev_region(&tmc_major, 0, TMC_DEV_MAX, "tmc"); > + if (ret < 0) { > + pr_err("tmc: failed to allocate char dev region\n"); > + return ret; > + } > + > + tmc_class = class_create(THIS_MODULE, "tmc"); > + if (IS_ERR(tmc_class)) { > + pr_err("failed to create tmc class\n"); > + ret = PTR_ERR(tmc_class); > + unregister_chrdev_region(tmc_major, TMC_DEV_MAX); > + return ret; > + } > + > + ret = amba_driver_register(&tmc_driver); > + if (ret) { > + pr_err("tmc: error registering amba driver\n"); > + class_destroy(tmc_class); > + unregister_chrdev_region(tmc_major, TMC_DEV_MAX); > + } > + > + return ret; > +} > + > +static void __exit tmc_exit(void) > +{ > + amba_driver_unregister(&tmc_driver); > + class_destroy(tmc_class); > + unregister_chrdev_region(tmc_major, TMC_DEV_MAX); > +} > + > +module_init(tmc_init); > +module_exit(tmc_exit); > > MODULE_AUTHOR("Pratik Patel "); > MODULE_DESCRIPTION("Arm CoreSight Trace Memory Controller driver"); > diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h > index 6bec20a392b3..b65ac363f9e4 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc.h > +++ b/drivers/hwtracing/coresight/coresight-tmc.h > @@ -7,6 +7,7 @@ > #ifndef _CORESIGHT_TMC_H > #define _CORESIGHT_TMC_H > > +#include > #include > #include > #include > @@ -163,11 +164,16 @@ struct etr_buf { > void *private; > }; > > +struct tmc_cdev { > + struct cdev cdev; > + struct device *dev; > +}; > + > /** > * struct tmc_drvdata - specifics associated to an TMC component > * @base: memory mapped base address for this component. > * @csdev: component vitals needed by the framework. > - * @miscdev: specifics to handle "/dev/xyz.tmc" entry. > + * @tmc_cdev: specifics to handle "/dev/xyz.tmc" entry. > * @spinlock: only one at a time pls. > * @pid: Process ID of the process being monitored by the session > * that is using this component. > @@ -191,7 +197,7 @@ struct etr_buf { > struct tmc_drvdata { > void __iomem *base; > struct coresight_device *csdev; > - struct miscdevice miscdev; > + struct tmc_cdev cdev; > spinlock_t spinlock; > pid_t pid; > bool reading; > -- > 2.27.0 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel