Good day Jay,

For your next iteration, please remove the "RFC" from the patch title, we are well pass that now.

On Tue, Dec 21, 2021 at 08:04:37PM +0800, Jay Chen 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 is much better.

Signed-off-by: Jay Chen jkchen@linux.alibaba.com

.../hwtracing/coresight/coresight-tmc-core.c | 91 +++++++++++++++---- drivers/hwtracing/coresight/coresight-tmc.h | 10 +- 2 files changed, 83 insertions(+), 18 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c index d0276af82494..0d51071e9f88 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-core.c +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c @@ -31,6 +31,12 @@ 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; @@ -147,7 +153,7 @@ 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 +185,7 @@ 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 +206,7 @@ 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) @@ -451,6 +457,7 @@ 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 +553,32 @@ 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 +608,11 @@ 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, dev->devt);

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 +641,43 @@ 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("tmc: failed to create class\n");
  

• ret = PTR_ERR(tmc_class);
  

• unregister_chrdev_region(tmc_major, TMC_DEV_MAX);
  

• return ret;
  

You can simply 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..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 <linux/cdev.h> #include <linux/dma-mapping.h> #include <linux/idr.h> #include <linux/miscdevice.h>

miscdevice.h can likely be removed in both .c and .h files.

Thanks, Mathieu

@@ -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