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Message-Id: <20211221120437.4781-1-jkchen@linux.alibaba.com>
Date: Tue, 21 Dec 2021 20:04:37 +0800
From: Jay Chen <jkchen@...ux.alibaba.com>
To: mathieu.poirier@...aro.org, suzuki.poulose@....com,
leo.yan@...aro.org, alexander.shishkin@...ux.intel.com,
linux-arm-kernel@...ts.infradead.org, coresight@...ts.linaro.org,
linux-kernel@...r.kernel.org
Cc: zhangliguang@...ux.alibaba.com
Subject: [RFC V3 PATCH] coresight: change tmc from misc device to cdev device
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@...ux.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);
+ 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;
+ }
+
+ 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@...eaurora.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>
@@ -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
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