diff mbox series

[RESEND,v2] coresight: change tmc from misc device to cdev device

Message ID 20220113061209.14271-1-jkchen@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series [RESEND,v2] coresight: change tmc from misc device to cdev device | expand

Commit Message

Jay Chen Jan. 13, 2022, 6:12 a.m. UTC
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.

Signed-off-by: Jay Chen <jkchen@linux.alibaba.com>
---
 .../hwtracing/coresight/coresight-tmc-core.c  | 103 ++++++++++++++----
 drivers/hwtracing/coresight/coresight-tmc.h   |  11 +-
 2 files changed, 91 insertions(+), 23 deletions(-)

Comments

Mathieu Poirier Jan. 13, 2022, 4:56 p.m. UTC | #1
On Wed, 12 Jan 2022 at 23:12, Jay Chen <jkchen@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.

On December 21st you posted this patch with a "RFC V3 PATCH" tag.  On
January 5th you posted a new version with a simple "PATCH" tag which,
minutes later, was superseded by another patch labelled "RESEND
PATCH".  Today you're sending yet another revision labelled "RESEND
PATCH V2"...

Is it a "V2" of the "RESEND PATCH" that was a new revision of the "RFC
V3 PATCH"?  Are you confused?  I certainly am...

>
> Signed-off-by: Jay Chen <jkchen@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@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
>
Jay Chen Jan. 14, 2022, 3:16 a.m. UTC | #2
Hi Mathieu

在 2022/1/14 00:56, Mathieu Poirier 写道:
> On Wed, 12 Jan 2022 at 23:12, Jay Chen <jkchen@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.
> On December 21st you posted this patch with a "RFC V3 PATCH" tag.  On
> January 5th you posted a new version with a simple "PATCH" tag which,
> minutes later, was superseded by another patch labelled "RESEND
> PATCH".  Today you're sending yet another revision labelled "RESEND
> PATCH V2"...
>
> Is it a "V2" of the "RESEND PATCH" that was a new revision of the "RFC
> V3 PATCH"?  Are you confused?  I certainly am...
>
this patch v2 is a new version,and it fix some bugs;

sorry

jay

>> Signed-off-by: Jay Chen <jkchen@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@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
>>
Mathieu Poirier Jan. 14, 2022, 4:55 a.m. UTC | #3
On Thu, 13 Jan 2022 at 20:16, Jiankang Chen <jkchen@linux.alibaba.com> wrote:
>
> Hi Mathieu
>
> 在 2022/1/14 00:56, Mathieu Poirier 写道:
> > On Wed, 12 Jan 2022 at 23:12, Jay Chen <jkchen@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.
> > On December 21st you posted this patch with a "RFC V3 PATCH" tag.  On
> > January 5th you posted a new version with a simple "PATCH" tag which,
> > minutes later, was superseded by another patch labelled "RESEND
> > PATCH".  Today you're sending yet another revision labelled "RESEND
> > PATCH V2"...
> >
> > Is it a "V2" of the "RESEND PATCH" that was a new revision of the "RFC
> > V3 PATCH"?  Are you confused?  I certainly am...
> >
> this patch v2 is a new version,and it fix some bugs;
>

How can it be a V2 when a V3 has already been published?  I will not
review this patch, and even less apply it, until it is properly
labelled.

> sorry
>
> jay
>
> >> Signed-off-by: Jay Chen <jkchen@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@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
> >>
Jay Chen Jan. 14, 2022, 6:32 a.m. UTC | #4
在 2022/1/14 12:55, Mathieu Poirier 写道:
> On Thu, 13 Jan 2022 at 20:16, Jiankang Chen <jkchen@linux.alibaba.com> wrote:
>> Hi Mathieu
>>
>> 在 2022/1/14 00:56, Mathieu Poirier 写道:
>>> On Wed, 12 Jan 2022 at 23:12, Jay Chen <jkchen@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.
>>> On December 21st you posted this patch with a "RFC V3 PATCH" tag.  On
>>> January 5th you posted a new version with a simple "PATCH" tag which,
>>> minutes later, was superseded by another patch labelled "RESEND
>>> PATCH".  Today you're sending yet another revision labelled "RESEND
>>> PATCH V2"...
>>>
>>> Is it a "V2" of the "RESEND PATCH" that was a new revision of the "RFC
>>> V3 PATCH"?  Are you confused?  I certainly am...
>>>
>> this patch v2 is a new version,and it fix some bugs;
>>
> How can it be a V2 when a V3 has already been published?  I will not
> review this patch, and even less apply it, until it is properly
> labelled.
>
OK, I'm going to revise the label and then send it

Thanks

Jay

>> sorry
>>
>> jay
>>
>>>> Signed-off-by: Jay Chen <jkchen@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@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
>>>>
diff mbox series

Patch

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@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;