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

This is helpful in examining ports' state.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Amit Shah 2009-12-21 22:36:21 +05:30 committed by Rusty Russell
parent 1f7aa42d16
commit d99393effd
1 changed files with 71 additions and 0 deletions
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71
drivers/char/virtio_console.c
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@ -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);