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Subject[PATCH 3/5] fsi: scom: Convert to use the new chardev
Date
This converts FSI scom to use the new fsi-core controlled
chardev allocator and use a real cdev instead of a miscdev.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
drivers/fsi/fsi-scom.c | 130 +++++++++++++++++++++++++----------------
1 file changed, 80 insertions(+), 50 deletions(-)

diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c
index 39c74351f1bf..0f303a700f69 100644
--- a/drivers/fsi/fsi-scom.c
+++ b/drivers/fsi/fsi-scom.c
@@ -20,9 +20,8 @@
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
-#include <linux/miscdevice.h>
+#include <linux/cdev.h>
#include <linux/list.h>
-#include <linux/idr.h>

#include <uapi/linux/fsi.h>

@@ -77,18 +76,12 @@
struct scom_device {
struct list_head link;
struct fsi_device *fsi_dev;
- struct miscdevice mdev;
+ struct device dev;
+ struct cdev cdev;
struct mutex lock;
- char name[32];
- int idx;
+ bool dead;
};

-#define to_scom_dev(x) container_of((x), struct scom_device, mdev)
-
-static struct list_head scom_devices;
-
-static DEFINE_IDA(scom_ida);
-
static int __put_scom(struct scom_device *scom_dev, uint64_t value,
uint32_t addr, uint32_t *status)
{
@@ -374,9 +367,7 @@ static int get_scom(struct scom_device *scom, uint64_t *value,
static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
loff_t *offset)
{
- struct miscdevice *mdev =
- (struct miscdevice *)filep->private_data;
- struct scom_device *scom = to_scom_dev(mdev);
+ struct scom_device *scom = filep->private_data;
struct device *dev = &scom->fsi_dev->dev;
uint64_t val;
int rc;
@@ -385,7 +376,10 @@ static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
return -EINVAL;

mutex_lock(&scom->lock);
- rc = get_scom(scom, &val, *offset);
+ if (scom->dead)
+ rc = -ENODEV;
+ else
+ rc = get_scom(scom, &val, *offset);
mutex_unlock(&scom->lock);
if (rc) {
dev_dbg(dev, "get_scom fail:%d\n", rc);
@@ -403,8 +397,7 @@ static ssize_t scom_write(struct file *filep, const char __user *buf,
size_t len, loff_t *offset)
{
int rc;
- struct miscdevice *mdev = filep->private_data;
- struct scom_device *scom = to_scom_dev(mdev);
+ struct scom_device *scom = filep->private_data;
struct device *dev = &scom->fsi_dev->dev;
uint64_t val;

@@ -418,7 +411,10 @@ static ssize_t scom_write(struct file *filep, const char __user *buf,
}

mutex_lock(&scom->lock);
- rc = put_scom(scom, val, *offset);
+ if (scom->dead)
+ rc = -ENODEV;
+ else
+ rc = put_scom(scom, val, *offset);
mutex_unlock(&scom->lock);
if (rc) {
dev_dbg(dev, "put_scom failed with:%d\n", rc);
@@ -532,12 +528,15 @@ static int scom_check(struct scom_device *scom, void __user *argp)

static long scom_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
- struct miscdevice *mdev = file->private_data;
- struct scom_device *scom = to_scom_dev(mdev);
+ struct scom_device *scom = file->private_data;
void __user *argp = (void __user *)arg;
int rc = -ENOTTY;

mutex_lock(&scom->lock);
+ if (scom->dead) {
+ mutex_unlock(&scom->lock);
+ return -ENODEV;
+ }
switch(cmd) {
case FSI_SCOM_CHECK:
rc = scom_check(scom, argp);
@@ -556,48 +555,88 @@ static long scom_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
return rc;
}

+static int scom_open(struct inode *inode, struct file *file)
+{
+ struct scom_device *scom = container_of(inode->i_cdev, struct scom_device, cdev);
+
+ file->private_data = scom;
+
+ return 0;
+}
+
static const struct file_operations scom_fops = {
.owner = THIS_MODULE,
+ .open = scom_open,
.llseek = scom_llseek,
.read = scom_read,
.write = scom_write,
.unlocked_ioctl = scom_ioctl,
};

+static void scom_free(struct device *dev)
+{
+ struct scom_device *scom = container_of(dev, struct scom_device, dev);
+
+ put_device(&scom->fsi_dev->dev);
+ kfree(scom);
+}
+
static int scom_probe(struct device *dev)
{
struct fsi_device *fsi_dev = to_fsi_dev(dev);
struct scom_device *scom;
+ int rc, didx;

- scom = devm_kzalloc(dev, sizeof(*scom), GFP_KERNEL);
+ scom = kzalloc(sizeof(*scom), GFP_KERNEL);
if (!scom)
return -ENOMEM;
-
+ dev_set_drvdata(dev, scom);
mutex_init(&scom->lock);
- scom->idx = ida_simple_get(&scom_ida, 1, INT_MAX, GFP_KERNEL);
- snprintf(scom->name, sizeof(scom->name), "scom%d", scom->idx);
- scom->fsi_dev = fsi_dev;
- scom->mdev.minor = MISC_DYNAMIC_MINOR;
- scom->mdev.fops = &scom_fops;
- scom->mdev.name = scom->name;
- scom->mdev.parent = dev;
- list_add(&scom->link, &scom_devices);
-
- return misc_register(&scom->mdev);
+
+ /* Grab a reference to the device (parent of our cdev), we'll drop it later */
+ if (!get_device(dev)) {
+ kfree(scom);
+ return -ENODEV;
+ }
+
+ /* Create chardev for userspace access */
+ scom->dev.type = &fsi_cdev_type;
+ scom->dev.parent = dev;
+ scom->dev.release = scom_free;
+ device_initialize(&scom->dev);
+
+ /* Allocate a minor in the FSI space */
+ rc = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx);
+ if (rc)
+ goto err;
+
+ dev_set_name(&scom->dev, "scom%d", didx);
+ cdev_init(&scom->cdev, &scom_fops);
+ rc = cdev_device_add(&scom->cdev, &scom->dev);
+ if (rc) {
+ dev_err(dev, "Error %d creating char device %s\n",
+ rc, dev_name(&scom->dev));
+ goto err_free_minor;
+ }
+
+ return 0;
+ err_free_minor:
+ fsi_free_minor(scom->dev.devt);
+ err:
+ put_device(&scom->dev);
+ return rc;
}

static int scom_remove(struct device *dev)
{
- struct scom_device *scom, *scom_tmp;
- struct fsi_device *fsi_dev = to_fsi_dev(dev);
+ struct scom_device *scom = dev_get_drvdata(dev);

- list_for_each_entry_safe(scom, scom_tmp, &scom_devices, link) {
- if (scom->fsi_dev == fsi_dev) {
- list_del(&scom->link);
- ida_simple_remove(&scom_ida, scom->idx);
- misc_deregister(&scom->mdev);
- }
- }
+ mutex_lock(&scom->lock);
+ scom->dead = true;
+ mutex_unlock(&scom->lock);
+ cdev_device_del(&scom->cdev, &scom->dev);
+ fsi_free_minor(scom->dev.devt);
+ put_device(&scom->dev);

return 0;
}
@@ -622,20 +661,11 @@ static struct fsi_driver scom_drv = {

static int scom_init(void)
{
- INIT_LIST_HEAD(&scom_devices);
return fsi_driver_register(&scom_drv);
}

static void scom_exit(void)
{
- struct list_head *pos;
- struct scom_device *scom;
-
- list_for_each(pos, &scom_devices) {
- scom = list_entry(pos, struct scom_device, link);
- misc_deregister(&scom->mdev);
- devm_kfree(&scom->fsi_dev->dev, scom);
- }
fsi_driver_unregister(&scom_drv);
}

--
2.17.1
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