[PATCH] coresight: tmc: change device registration from misc to cdev
Mathieu Poirier
mathieu.poirier at linaro.org
Tue Jan 25 08:46:25 PST 2022
On Tue, Jan 25, 2022 at 10:33:45AM +0800, Jiankang Chen wrote:
> Hi Mathieu
>
> 在 2022/1/25 04:08, Mathieu Poirier 写道:
> > On Mon, 24 Jan 2022 at 04:00, Jay Chen <jkchen at linux.alibaba.com> wrote:
> > > Currently, there are 130 etr and etf on our machine,
> > > but the current coresight tmc driver uses misc_register
> > > to register the device, which leads to the error that
> > > the device number is not enough.
> > >
> > > coresight-tmc: probe of xxxxx failed with error -16
> > >
> > > This patch changes the device registration method
> > > to cdev's dynamic registration method to solve the
> > > problem of insufficient device numbers.
> > This patch is still not labelled properly and as such being dropped.
>
> Hello, about the label of this patch, what kind of patch should I add?
>
So far you've sent 6 different version of this patch... Wouldn't it make sense
to label this one "PATCH v7" ?
Leo has pointed out a good presentation from Marc Zingier - I also suggest you
invest time reading it.
> Thanks very much
>
> jay
>
> > > Signed-off-by: Jay Chen <jkchen at linux.alibaba.com>
> > > ---
> > > .../hwtracing/coresight/coresight-tmc-core.c | 103 ++++++++++++++----
> > > drivers/hwtracing/coresight/coresight-tmc.h | 11 +-
> > > 2 files changed, 91 insertions(+), 23 deletions(-)
> > >
> > > diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> > > index d0276af82494..0977f1ce6338 100644
> > > --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> > > +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
> > > @@ -12,7 +12,6 @@
> > > #include <linux/io.h>
> > > #include <linux/err.h>
> > > #include <linux/fs.h>
> > > -#include <linux/miscdevice.h>
> > > #include <linux/mutex.h>
> > > #include <linux/property.h>
> > > #include <linux/uaccess.h>
> > > @@ -31,6 +30,12 @@ DEFINE_CORESIGHT_DEVLIST(etb_devs, "tmc_etb");
> > > DEFINE_CORESIGHT_DEVLIST(etf_devs, "tmc_etf");
> > > DEFINE_CORESIGHT_DEVLIST(etr_devs, "tmc_etr");
> > >
> > > +static DEFINE_IDA(tmc_ida);
> > > +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;
> > > @@ -146,8 +151,10 @@ static int tmc_read_unprepare(struct tmc_drvdata *drvdata)
> > > 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_cdev *cdev = container_of(inode->i_cdev,
> > > + struct tmc_cdev, cdev);
> > > + struct tmc_drvdata *drvdata = container_of(cdev,
> > > + struct tmc_drvdata, cdev);
> > >
> > > ret = tmc_read_prepare(drvdata);
> > > if (ret)
> > > @@ -178,8 +185,10 @@ 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_cdev *cdev = container_of(file->f_inode->i_cdev,
> > > + struct tmc_cdev, cdev);
> > > + struct tmc_drvdata *drvdata = container_of(cdev,
> > > + struct tmc_drvdata, cdev);
> > > actual = tmc_get_sysfs_trace(drvdata, *ppos, len, &bufp);
> > > if (actual <= 0)
> > > return 0;
> > > @@ -199,8 +208,10 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
> > > 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_cdev *cdev = container_of(inode->i_cdev,
> > > + struct tmc_cdev, cdev);
> > > + struct tmc_drvdata *drvdata = container_of(cdev,
> > > + struct tmc_drvdata, cdev);
> > >
> > > ret = tmc_read_unprepare(drvdata);
> > > if (ret)
> > > @@ -451,6 +462,7 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
> > > {
> > > int ret = 0;
> > > u32 devid;
> > > + dev_t devt;
> > > void __iomem *base;
> > > struct device *dev = &adev->dev;
> > > struct coresight_platform_data *pdata = NULL;
> > > @@ -546,14 +558,32 @@ 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);
> > > + ret = ida_simple_get(&tmc_ida, 0, TMC_DEV_MAX, GFP_KERNEL);
> > > + if (ret < 0)
> > > + goto err_coresight_unregister;
> > > +
> > > + cdev_init(&drvdata->cdev.cdev, &tmc_fops);
> > > + drvdata->cdev.cdev.owner = THIS_MODULE;
> > > + devt = MKDEV(MAJOR(tmc_major), ret);
> > > + ret = cdev_add(&drvdata->cdev.cdev, devt, 1);
> > > if (ret)
> > > - coresight_unregister(drvdata->csdev);
> > > - else
> > > + goto err_free_tmc_ida;
> > > +
> > > + 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);
> > > + goto err_delete_cdev;
> > > + } else
> > > pm_runtime_put(&adev->dev);
> > > +
> > > + return 0;
> > > +
> > > +err_delete_cdev:
> > > + cdev_del(&drvdata->cdev.cdev);
> > > +err_free_tmc_ida:
> > > + ida_simple_remove(&tmc_ida, MINOR(devt));
> > > +err_coresight_unregister:
> > > + coresight_unregister(drvdata->csdev);
> > > out:
> > > return ret;
> > > }
> > > @@ -583,13 +613,11 @@ static void tmc_shutdown(struct amba_device *adev)
> > > static void tmc_remove(struct amba_device *adev)
> > > {
> > > struct tmc_drvdata *drvdata = dev_get_drvdata(&adev->dev);
> > > + struct device *dev = drvdata->cdev.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);
> > > + ida_simple_remove(&tmc_ida, MINOR(dev->devt));
> > > + device_destroy(tmc_class, dev->devt);
> > > + cdev_del(&drvdata->cdev.cdev);
> > > coresight_unregister(drvdata->csdev);
> > > }
> > >
> > > @@ -618,7 +646,42 @@ 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("tmc: failed to create class\n");
> > > + unregister_chrdev_region(tmc_major, TMC_DEV_MAX);
> > > + return PTR_ERR(tmc_class);
> > > + }
> > > +
> > > + 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 <pratikp at codeaurora.org>");
> > > 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..11441c6b9c26 100644
> > > --- a/drivers/hwtracing/coresight/coresight-tmc.h
> > > +++ b/drivers/hwtracing/coresight/coresight-tmc.h
> > > @@ -7,9 +7,9 @@
> > > #ifndef _CORESIGHT_TMC_H
> > > #define _CORESIGHT_TMC_H
> > >
> > > +#include <linux/cdev.h>
> > > #include <linux/dma-mapping.h>
> > > #include <linux/idr.h>
> > > -#include <linux/miscdevice.h>
> > > #include <linux/mutex.h>
> > > #include <linux/refcount.h>
> > >
> > > @@ -163,11 +163,16 @@ 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 +196,7 @@ 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
> > >
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