[RESEND PATCH v2] coresight: change tmc from misc device to cdev device
Mathieu Poirier
mathieu.poirier at linaro.org
Thu Jan 13 20:55:57 PST 2022
On Thu, 13 Jan 2022 at 20:16, Jiankang Chen <jkchen at 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 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.
> > 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 minutes later, was superseded by another patch labelled "RESEND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 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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