misc: mic: SCIF open close bind and listen APIs

SCIF character device file operations and kernel APIs for opening and
closing a user and kernel mode SCIF endpoint. This patch also enables
binding to a SCIF port and listening for incoming SCIF connections.

Reviewed-by: Nikhil Rao <nikhil.rao@intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 104 insertions, 0 deletions

diff --git a/drivers/misc/mic/scif/scif_fd.c b/drivers/misc/mic/scif/scif_fd.c
new file mode 100644
index 000000000000..812c23f9853c
--- /dev/null
+++ b/drivers/misc/mic/scif/scif_fd.c
@@ -0,0 +1,104 @@
+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * Copyright(c) 2014 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * Intel SCIF driver.
+ *
+ */
+#include "scif_main.h"
+
+static int scif_fdopen(struct inode *inode, struct file *f)
+{
+	struct scif_endpt *priv = scif_open();
+
+	if (!priv)
+		return -ENOMEM;
+	f->private_data = priv;
+	return 0;
+}
+
+static int scif_fdclose(struct inode *inode, struct file *f)
+{
+	struct scif_endpt *priv = f->private_data;
+
+	return scif_close(priv);
+}
+
+static int scif_fdflush(struct file *f, fl_owner_t id)
+{
+	struct scif_endpt *ep = f->private_data;
+
+	spin_lock(&ep->lock);
+	/*
+	 * The listening endpoint stashes the open file information before
+	 * waiting for incoming connections. The release callback would never be
+	 * called if the application closed the endpoint, while waiting for
+	 * incoming connections from a separate thread since the file descriptor
+	 * reference count is bumped up in the accept IOCTL. Call the flush
+	 * routine if the id matches the endpoint open file information so that
+	 * the listening endpoint can be woken up and the fd released.
+	 */
+	if (ep->files == id)
+		__scif_flush(ep);
+	spin_unlock(&ep->lock);
+	return 0;
+}
+
+static __always_inline void scif_err_debug(int err, const char *str)
+{
+	/*
+	 * ENOTCONN is a common uninteresting error which is
+	 * flooding debug messages to the console unnecessarily.
+	 */
+	if (err < 0 && err != -ENOTCONN)
+		dev_dbg(scif_info.mdev.this_device, "%s err %d\n", str, err);
+}
+
+static long scif_fdioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+	struct scif_endpt *priv = f->private_data;
+	void __user *argp = (void __user *)arg;
+	bool non_block = false;
+
+	non_block = !!(f->f_flags & O_NONBLOCK);
+
+	switch (cmd) {
+	case SCIF_BIND:
+	{
+		int pn;
+
+		if (copy_from_user(&pn, argp, sizeof(pn)))
+			return -EFAULT;
+
+		pn = scif_bind(priv, pn);
+		if (pn < 0)
+			return pn;
+
+		if (copy_to_user(argp, &pn, sizeof(pn)))
+			return -EFAULT;
+
+		return 0;
+	}
+	case SCIF_LISTEN:
+		return scif_listen(priv, arg);
+	}
+	return -EINVAL;
+}
+
+const struct file_operations scif_fops = {
+	.open = scif_fdopen,
+	.release = scif_fdclose,
+	.unlocked_ioctl = scif_fdioctl,
+	.flush = scif_fdflush,
+	.owner = THIS_MODULE,
+};