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Commit d99393ef authored by Amit Shah's avatar Amit Shah Committed by Rusty Russell
Browse files

virtio: console: Add debugfs files for each port to expose debug info 



This is helpful in examining ports' state.

Signed-off-by: default avatarAmit Shah <amit.shah@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 1f7aa42d

drivers/char/virtio_console.c

+71 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include <linux/cdev.h>

#include <linux/debugfs.h>

#include <linux/device.h>

#include <linux/err.h>

#include <linux/fs.h>
@@ -43,6 +44,9 @@ struct ports_driver_data { 
	/* Used for registering chardevs */

	struct class *class;



	/* Used for exporting per-port information to debugfs */

	struct dentry *debugfs_dir;



	/* Number of devices this driver is handling */

	unsigned int index;
@@ -158,6 +162,9 @@ struct port { 
	/* The IO vqs for this port */

	struct virtqueue *in_vq, *out_vq;



	/* File in the debugfs directory that exposes this port's information */

	struct dentry *debugfs_file;



	/*

	 * The entries in this struct will be valid if this port is

	 * hooked up to an hvc console
@@ -783,6 +790,49 @@ static struct attribute_group port_attribute_group = { 
	.attrs = port_sysfs_entries,

};



static int debugfs_open(struct inode *inode, struct file *filp)

{

	filp->private_data = inode->i_private;

	return 0;

}



static ssize_t debugfs_read(struct file *filp, char __user *ubuf,

			    size_t count, loff_t *offp)

{

	struct port *port;

	char *buf;

	ssize_t ret, out_offset, out_count;



	out_count = 1024;

	buf = kmalloc(out_count, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	port = filp->private_data;

	out_offset = 0;

	out_offset += snprintf(buf + out_offset, out_count,

			       "name: %s\n", port->name ? port->name : "");

	out_offset += snprintf(buf + out_offset, out_count - out_offset,

			       "guest_connected: %d\n", port->guest_connected);

	out_offset += snprintf(buf + out_offset, out_count - out_offset,

			       "host_connected: %d\n", port->host_connected);

	out_offset += snprintf(buf + out_offset, out_count - out_offset,

			       "is_console: %s\n",

			       is_console_port(port) ? "yes" : "no");

	out_offset += snprintf(buf + out_offset, out_count - out_offset,

			       "console_vtermno: %u\n", port->cons.vtermno);



	ret = simple_read_from_buffer(ubuf, count, offp, buf, out_offset);

	kfree(buf);

	return ret;

}



static const struct file_operations port_debugfs_ops = {

	.owner = THIS_MODULE,

	.open  = debugfs_open,

	.read  = debugfs_read,

};



/* Remove all port-specific data. */

static int remove_port(struct port *port)

{
@@ -809,6 +859,8 @@ static int remove_port(struct port *port) 
	discard_port_data(port);

	kfree(port->name);



	debugfs_remove(port->debugfs_file);



	kfree(port);

	return 0;

}
@@ -1021,6 +1073,7 @@ static void fill_queue(struct virtqueue *vq, spinlock_t *lock) 


static int add_port(struct ports_device *portdev, u32 id)

{

	char debugfs_name[16];

	struct port *port;

	struct port_buffer *inbuf;

	dev_t devt;
@@ -1096,6 +1149,18 @@ static int add_port(struct ports_device *portdev, u32 id) 
	 */

	send_control_msg(port, VIRTIO_CONSOLE_PORT_READY, 1);



	if (pdrvdata.debugfs_dir) {

		/*

		 * Finally, create the debugfs file that we can use to

		 * inspect a port's state at any time

		 */

		sprintf(debugfs_name, "vport%up%u",

			port->portdev->drv_index, id);

		port->debugfs_file = debugfs_create_file(debugfs_name, 0444,

							 pdrvdata.debugfs_dir,

							 port,

							 &port_debugfs_ops);

	}

	return 0;



free_inbuf:
@@ -1406,6 +1471,12 @@ static int __init init(void) 
		pr_err("Error %d creating virtio-ports class\n", err);

		return err;

	}



	pdrvdata.debugfs_dir = debugfs_create_dir("virtio-ports", NULL);

	if (!pdrvdata.debugfs_dir) {

		pr_warning("Error %ld creating debugfs dir for virtio-ports\n",

			   PTR_ERR(pdrvdata.debugfs_dir));

	}

	INIT_LIST_HEAD(&pdrvdata.consoles);



	return register_virtio_driver(&virtio_console);