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Commit 20f1caf0 authored by Pavankumar Kondeti's avatar Pavankumar Kondeti
Browse files

USB: ccid_bridge: Provide bulk message write/read stats via debugfs 



The bulk message timeouts are observed occasionally during mass storage
transfers. This debug facility helps in identifying such timeout issues.

The sample output of the stats debugfs file.

ccid_bridge: connected
ccid_bridge: opened
total writes: 444
total reads: 444
write/read timeout val: 1000
write_timeout: 0
read_timeout: 0
write_max_time (msec): 130
read_max_time: (msec): 857

CRs-Fixed: 659909
Change-Id: I9787288c10d23b176c9316feed82d41bd2adae65
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
parent 5dd6baeb

drivers/usb/class/ccid_bridge.c

+123 −4
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
#include <linux/usb.h>

#include <linux/wait.h>

#include <linux/cdev.h>

#include <linux/ktime.h>

#include <linux/debugfs.h>



#include <linux/usb/ccid_bridge.h>
@@ -71,6 +73,14 @@ struct ccid_bridge { 
	struct cdev cdev;

	struct class *class;

	struct device *device;



	struct dentry *dbg_root;

	unsigned n_write;

	unsigned n_read;

	unsigned n_write_timeout;

	unsigned n_read_timeout;

	unsigned long write_max_time;

	unsigned long read_max_time;

};



static struct ccid_bridge *__ccid_bridge_dev;
@@ -260,6 +270,7 @@ static ssize_t ccid_bridge_write(struct file *fp, const char __user *ubuf, 
	struct ccid_bridge *ccid = fp->private_data;

	int ret;

	char *kbuf;

	ktime_t start_t, delta_t;



	pr_debug("called with %d", count);
@@ -270,6 +281,9 @@ static ssize_t ccid_bridge_write(struct file *fp, const char __user *ubuf, 


	mutex_lock(&ccid->write_mutex);



	ccid->n_write++;

	start_t = ktime_get();



	if (!count || count > CCID_BRIDGE_MSG_SZ) {

		pr_err("invalid count");

		ret = -EINVAL;
@@ -311,12 +325,20 @@ static ssize_t ccid_bridge_write(struct file *fp, const char __user *ubuf, 
			msecs_to_jiffies(ccid_bulk_msg_timeout));

	if (!ret || ret == -ERESTARTSYS) { /* timedout or interrupted */

		usb_kill_urb(ccid->writeurb);

		if (!ret)

		if (!ret) {

			ccid->n_write_timeout++;

			ret = -ETIMEDOUT;

		}

	} else {

		ret = ccid->write_result;

	}



	if (ret >= 0) {

		delta_t = ktime_sub(ktime_get(), start_t);

		if (ktime_to_ms(delta_t) > ccid->write_max_time)

			ccid->write_max_time = ktime_to_ms(delta_t);

	}



	pr_debug("returning %d", ret);



put_pm:
@@ -336,6 +358,7 @@ static ssize_t ccid_bridge_read(struct file *fp, char __user *ubuf, 
	struct ccid_bridge *ccid = fp->private_data;

	int ret;

	char *kbuf;

	ktime_t start_t, delta_t;



	pr_debug("called with %d", count);

	if (!ccid->intf) {
@@ -345,6 +368,9 @@ static ssize_t ccid_bridge_read(struct file *fp, char __user *ubuf, 


	mutex_lock(&ccid->read_mutex);



	ccid->n_read++;

	start_t = ktime_get();



	if (!count || count > CCID_BRIDGE_MSG_SZ) {

		pr_err("invalid count");

		ret = -EINVAL;
@@ -376,22 +402,26 @@ static ssize_t ccid_bridge_read(struct file *fp, char __user *ubuf, 
		goto free_kbuf;

	}





	ret = wait_event_interruptible_timeout(ccid->read_wq,

			ccid->read_result != 0,

			msecs_to_jiffies(ccid_bulk_msg_timeout));

	if (!ret || ret == -ERESTARTSYS) { /* timedout or interrupted */

		usb_kill_urb(ccid->readurb);

		if (!ret)

		if (!ret) {

			ccid->n_read_timeout++;

			ret = -ETIMEDOUT;

		}

	} else {

		ret = ccid->read_result;

	}





	if (ret > 0) {

		if (copy_to_user(ubuf, kbuf, ret))

			ret = -EFAULT;



		delta_t = ktime_sub(ktime_get(), start_t);

		if (ktime_to_ms(delta_t) > ccid->read_max_time)

			ccid->read_max_time = ktime_to_ms(delta_t);

	}



	usb_autopm_put_interface(ccid->intf);
@@ -537,6 +567,16 @@ ccid_bridge_ioctl(struct file *fp, unsigned int cmd, unsigned long arg) 
	return ret;

}



static void ccid_bridge_reset_stats(struct ccid_bridge *ccid)

{

	ccid->n_write = 0;

	ccid->n_read = 0;

	ccid->n_write_timeout = 0;

	ccid->n_read_timeout = 0;

	ccid->write_max_time = 0;

	ccid->read_max_time = 0;

}



static int ccid_bridge_release(struct inode *ip, struct file *fp)

{

	struct ccid_bridge *ccid = fp->private_data;
@@ -563,6 +603,7 @@ static int ccid_bridge_release(struct inode *ip, struct file *fp) 
	ccid->opened = false;

	mutex_unlock(&ccid->open_mutex);

done:

	ccid_bridge_reset_stats(ccid);

	return 0;

}
@@ -792,6 +833,80 @@ static struct usb_driver ccid_bridge_driver = { 
	.supports_autosuspend = 1,

};



static int ccid_bridge_stats_show(struct seq_file *s, void *unused)

{

	struct ccid_bridge *ccid = s->private;



	seq_printf(s, "ccid_bridge: %s\n",

			ccid->intf ? "connected" : "disconnected");

	seq_printf(s, "ccid_bridge: %s\n",

			ccid->opened ? "opened" : "closed");



	seq_printf(s, "total writes: %u\n", ccid->n_write);

	seq_printf(s, "total reads: %u\n", ccid->n_write);



	seq_printf(s, "write/read timeout val: %u\n", ccid_bulk_msg_timeout);



	seq_printf(s, "write_timeout: %u\n", ccid->n_write_timeout);

	seq_printf(s, "read_timeout: %u\n", ccid->n_read_timeout);



	seq_printf(s, "write_max_time (msec): %lu\n", ccid->write_max_time);

	seq_printf(s, "read_max_time: (msec): %lu\n", ccid->read_max_time);



	return 0;

}



static int ccid_bridge_stats_open(struct inode *inode, struct file *file)

{

	return single_open(file, ccid_bridge_stats_show, inode->i_private);

}



static ssize_t ccid_bridge_stats_write(struct file *file,

				const char __user *ubuf,

				size_t count, loff_t *ppos)

{

	struct seq_file *s = file->private_data;

	struct ccid_bridge *ccid = s->private;



	ccid_bridge_reset_stats(ccid);

	return count;

}



const struct file_operations ccid_bridge_stats_ops = {

	.open = ccid_bridge_stats_open,

	.read = seq_read,

	.write = ccid_bridge_stats_write,

	.llseek = seq_lseek,

	.release = single_release,

};



static int ccid_bridge_debugfs_init(struct ccid_bridge *ccid)

{

	struct dentry *dir;

	int ret = 0;



	dir = debugfs_create_dir("ccid_bridge", NULL);



	if (!dir || IS_ERR(dir)) {

		ret = -ENODEV;

		goto out;

	}



	ccid->dbg_root = dir;



	dir = debugfs_create_file("stats", 0644, ccid->dbg_root, ccid,

			&ccid_bridge_stats_ops);



	if (!dir) {

		debugfs_remove_recursive(ccid->dbg_root);

		ccid->dbg_root = NULL;

		ret = -ENODEV;

	}



out:

	return ret;

}



static int __init ccid_bridge_init(void)

{

	int ret;
@@ -849,6 +964,8 @@ static int __init ccid_bridge_init(void) 
		goto del_cdev;

	}



	ccid_bridge_debugfs_init(ccid);



	pr_info("success");



	return 0;
@@ -877,6 +994,8 @@ static void __exit ccid_bridge_exit(void) 
	struct ccid_bridge *ccid = __ccid_bridge_dev;



	pr_debug("called");



	debugfs_remove_recursive(ccid->dbg_root);

	device_destroy(ccid->class, ccid->chrdev);

	cdev_del(&ccid->cdev);

	class_destroy(ccid->class);