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Subject[PATCH 04/12] misc: xilinx_sdfec: Add open, close and ioctl
Date
Add char device interface per DT node present and support
file operations:
- open(), which keeps only one open per device at a time,
- close(), which release the open for this device,
- ioctl(), which provides infrastructure for a specific driver
control.

Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Dragan Cvetic <dragan.cvetic@xilinx.com>
Signed-off-by: Derek Kiernan <derek.kiernan@xilinx.com>
Signed-off-by: Dragan Cvetic <dragan.cvetic@xilinx.com>
---
drivers/misc/xilinx_sdfec.c | 79 ++++++++++++++++++++++++++++++++++++++++
include/uapi/misc/xilinx_sdfec.h | 4 ++
2 files changed, 83 insertions(+)

diff --git a/drivers/misc/xilinx_sdfec.c b/drivers/misc/xilinx_sdfec.c
index a52a5c6..3407de4 100644
--- a/drivers/misc/xilinx_sdfec.c
+++ b/drivers/misc/xilinx_sdfec.c
@@ -81,8 +81,87 @@ struct xsdfec_dev {
struct xsdfec_clks clks;
};

+static int xsdfec_dev_open(struct inode *iptr, struct file *fptr)
+{
+ struct xsdfec_dev *xsdfec;
+
+ xsdfec = container_of(iptr->i_cdev, struct xsdfec_dev, xsdfec_cdev);
+ if (!xsdfec)
+ return -EAGAIN;
+
+ /* Only one open per device at a time */
+ if (!atomic_dec_and_test(&xsdfec->open_count)) {
+ atomic_inc(&xsdfec->open_count);
+ return -EBUSY;
+ }
+
+ fptr->private_data = xsdfec;
+ return 0;
+}
+
+static int xsdfec_dev_release(struct inode *iptr, struct file *fptr)
+{
+ struct xsdfec_dev *xsdfec;
+
+ xsdfec = container_of(iptr->i_cdev, struct xsdfec_dev, xsdfec_cdev);
+ if (!xsdfec)
+ return -EAGAIN;
+
+ atomic_inc(&xsdfec->open_count);
+ return 0;
+}
+
+static long xsdfec_dev_ioctl(struct file *fptr, unsigned int cmd,
+ unsigned long data)
+{
+ struct xsdfec_dev *xsdfec = fptr->private_data;
+ void __user *arg = NULL;
+ int rval = -EINVAL;
+ int err = 0;
+
+ if (!xsdfec)
+ return rval;
+
+ if (_IOC_TYPE(cmd) != XSDFEC_MAGIC) {
+ dev_err(xsdfec->dev, "Not a xilinx sdfec ioctl");
+ return -ENOTTY;
+ }
+
+ /* check if ioctl argument is present and valid */
+ if (_IOC_DIR(cmd) != _IOC_NONE) {
+ arg = (void __user *)data;
+ if (!arg) {
+ dev_err(xsdfec->dev,
+ "xilinx sdfec ioctl argument is NULL Pointer");
+ return rval;
+ }
+ }
+
+ /* Access check of the argument if present */
+ if (_IOC_DIR(cmd) & _IOC_READ)
+ err = !access_ok((void *)arg, _IOC_SIZE(cmd));
+ else if (_IOC_DIR(cmd) & _IOC_WRITE)
+ err = !access_ok((void *)arg, _IOC_SIZE(cmd));
+
+ if (err) {
+ dev_err(xsdfec->dev, "Invalid xilinx sdfec ioctl argument");
+ return -EFAULT;
+ }
+
+ switch (cmd) {
+ default:
+ /* Should not get here */
+ dev_err(xsdfec->dev, "Undefined SDFEC IOCTL");
+ break;
+ }
+ return rval;
+}
+
static const struct file_operations xsdfec_fops = {
.owner = THIS_MODULE,
+ .open = xsdfec_dev_open,
+ .release = xsdfec_dev_release,
+ .unlocked_ioctl = xsdfec_dev_ioctl,
};

static int xsdfec_clk_init(struct platform_device *pdev,
diff --git a/include/uapi/misc/xilinx_sdfec.h b/include/uapi/misc/xilinx_sdfec.h
index 5543163..5de0add 100644
--- a/include/uapi/misc/xilinx_sdfec.h
+++ b/include/uapi/misc/xilinx_sdfec.h
@@ -39,4 +39,8 @@ struct xsdfec_config {
s32 fec_id;
};

+/*
+ * XSDFEC IOCTL List
+ */
+#define XSDFEC_MAGIC 'f'
#endif /* __XILINX_SDFEC_H__ */
--
2.7.4
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