staging: ozwpan: Replace existing event logging mechanism

This patch replaces existing event logging mechanism from ioctl to debugfs.
This patch replaces previous patch submitted by Chris Kelly. Previous patch can
be found at :-
http://article.gmane.org/gmane.linux.usb.general/60026/

Signed-off-by: Rupesh Gujare <rgujare@ozmodevices.com>
Signed-off-by: Chris Kelly <ckelly@ozmodevices.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

6 files changed, 158 insertions, 104 deletions

diff --git a/drivers/staging/ozwpan/ozappif.h b/drivers/staging/ozwpan/ozappif.h
index af027329387..1b59b0748c6 100644
--- a/drivers/staging/ozwpan/ozappif.h
+++ b/drivers/staging/ozwpan/ozappif.h
@@ -11,13 +11,13 @@
 #define OZ_IOCTL_MAGIC	0xf4
 
 struct oz_mac_addr {
-	unsigned char a[6];
+	__u8 a[6];
 };
 
 #define OZ_MAX_PDS	8
 
 struct oz_pd_list {
-	int count;
+	__u32 count;
 	struct oz_mac_addr addr[OZ_MAX_PDS];
 };
 
@@ -27,18 +27,10 @@ struct oz_binding_info {
 	char name[OZ_MAX_BINDING_LEN];
 };
 
-struct oz_test {
-	int action;
-};
-
 #define OZ_IOCTL_GET_PD_LIST	_IOR(OZ_IOCTL_MAGIC, 0, struct oz_pd_list)
 #define OZ_IOCTL_SET_ACTIVE_PD	_IOW(OZ_IOCTL_MAGIC, 1, struct oz_mac_addr)
 #define OZ_IOCTL_GET_ACTIVE_PD	_IOR(OZ_IOCTL_MAGIC, 2, struct oz_mac_addr)
-#define OZ_IOCTL_CLEAR_EVENTS	_IO(OZ_IOCTL_MAGIC, 3)
-#define OZ_IOCTL_GET_EVENTS	_IOR(OZ_IOCTL_MAGIC, 4, struct oz_evtlist)
 #define OZ_IOCTL_ADD_BINDING	_IOW(OZ_IOCTL_MAGIC, 5, struct oz_binding_info)
-#define OZ_IOCTL_TEST		_IOWR(OZ_IOCTL_MAGIC, 6, struct oz_test)
-#define OZ_IOCTL_SET_EVENT_MASK	_IOW(OZ_IOCTL_MAGIC, 7, unsigned long)
 #define OZ_IOCTL_REMOVE_BINDING	_IOW(OZ_IOCTL_MAGIC, 8, struct oz_binding_info)
 #define OZ_IOCTL_MAX		9
 
diff --git a/drivers/staging/ozwpan/ozcdev.c b/drivers/staging/ozwpan/ozcdev.c
index 1c380d68796..27325f74ecd 100644
--- a/drivers/staging/ozwpan/ozcdev.c
+++ b/drivers/staging/ozwpan/ozcdev.c
@@ -41,9 +41,6 @@ struct oz_serial_ctx {
 };
 /*------------------------------------------------------------------------------
  */
-int g_taction;
-/*------------------------------------------------------------------------------
- */
 static struct oz_cdev g_cdev;
 /*------------------------------------------------------------------------------
  * Context: process and softirq
@@ -276,20 +273,6 @@ long oz_cdev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 				return -EFAULT;
 		}
 		break;
-#ifdef WANT_EVENT_TRACE
-	case OZ_IOCTL_CLEAR_EVENTS:
-		oz_events_clear();
-		break;
-	case OZ_IOCTL_GET_EVENTS:
-		rc = oz_events_copy((void __user *)arg);
-		break;
-	case OZ_IOCTL_SET_EVENT_MASK:
-		if (copy_from_user(&g_evt_mask, (void __user *)arg,
-			sizeof(unsigned long))) {
-			return -EFAULT;
-		}
-		break;
-#endif /* WANT_EVENT_TRACE */
 	case OZ_IOCTL_ADD_BINDING:
 	case OZ_IOCTL_REMOVE_BINDING: {
 			struct oz_binding_info b;
diff --git a/drivers/staging/ozwpan/ozevent.c b/drivers/staging/ozwpan/ozevent.c
index 73703d3e96b..7f66b4f19b0 100644
--- a/drivers/staging/ozwpan/ozevent.c
+++ b/drivers/staging/ozwpan/ozevent.c
@@ -5,29 +5,46 @@
  */
 #include "ozconfig.h"
 #ifdef WANT_EVENT_TRACE
+#include <linux/module.h>
+#include <linux/debugfs.h>
 #include <linux/jiffies.h>
 #include <linux/uaccess.h>
 #include "oztrace.h"
 #include "ozevent.h"
+#include "ozappif.h"
 /*------------------------------------------------------------------------------
+ * Although the event mask is logically part of the oz_evtdev structure, it is
+ * needed outside of this file so define it seperately to avoid the need to
+ * export definition of struct oz_evtdev.
  */
-unsigned long g_evt_mask = 0xffffffff;
+u32 g_evt_mask;
 /*------------------------------------------------------------------------------
  */
 #define OZ_MAX_EVTS	2048	/* Must be power of 2 */
-DEFINE_SPINLOCK(g_eventlock);
-static int g_evt_in;
-static int g_evt_out;
-static int g_missed_events;
-static struct oz_event g_events[OZ_MAX_EVTS];
+struct oz_evtdev {
+	struct dentry *root_dir;
+	int evt_in;
+	int evt_out;
+	int missed_events;
+	int present;
+	atomic_t users;
+	spinlock_t lock;
+	struct oz_event evts[OZ_MAX_EVTS];
+};
+
+static struct oz_evtdev g_evtdev;
+
 /*------------------------------------------------------------------------------
  * Context: process
  */
 void oz_event_init(void)
 {
+	/* Because g_evtdev is static external all fields initally zero so no
+	 * need to reinitialised those.
+	 */
 	oz_trace("Event tracing initialized\n");
-	g_evt_in = g_evt_out = 0;
-	g_missed_events = 0;
+	spin_lock_init(&g_evtdev.lock);
+	atomic_set(&g_evtdev.users, 0);
 }
 /*------------------------------------------------------------------------------
  * Context: process
@@ -43,74 +60,136 @@ void oz_event_log2(u8 evt, u8 ctx1, u16 ctx2, void *ctx3, unsigned ctx4)
 {
 	unsigned long irqstate;
 	int ix;
-	spin_lock_irqsave(&g_eventlock, irqstate);
-	ix = (g_evt_in + 1) & (OZ_MAX_EVTS - 1);
-	if (ix != g_evt_out) {
-		struct oz_event *e = &g_events[g_evt_in];
+	spin_lock_irqsave(&g_evtdev.lock, irqstate);
+	ix = (g_evtdev.evt_in + 1) & (OZ_MAX_EVTS - 1);
+	if (ix != g_evtdev.evt_out) {
+		struct oz_event *e = &g_evtdev.evts[g_evtdev.evt_in];
 		e->jiffies = jiffies;
 		e->evt = evt;
 		e->ctx1 = ctx1;
 		e->ctx2 = ctx2;
-		e->ctx3 = ctx3;
+		e->ctx3 = (__u32)(unsigned long)ctx3;
 		e->ctx4 = ctx4;
-		g_evt_in = ix;
+		g_evtdev.evt_in = ix;
 	} else {
-		g_missed_events++;
+		g_evtdev.missed_events++;
 	}
-	spin_unlock_irqrestore(&g_eventlock, irqstate);
+	spin_unlock_irqrestore(&g_evtdev.lock, irqstate);
 }
 /*------------------------------------------------------------------------------
  * Context: process
  */
-int oz_events_copy(struct oz_evtlist __user *lst)
+static void oz_events_clear(struct oz_evtdev *dev)
 {
-	int first;
-	int ix;
-	struct hdr {
-		int count;
-		int missed;
-	} hdr;
-	ix = g_evt_out;
-	hdr.count = g_evt_in - ix;
-	if (hdr.count < 0)
-		hdr.count += OZ_MAX_EVTS;
-	if (hdr.count > OZ_EVT_LIST_SZ)
-		hdr.count = OZ_EVT_LIST_SZ;
-	hdr.missed = g_missed_events;
-	g_missed_events = 0;
-	if (copy_to_user((void __user *)lst, &hdr, sizeof(hdr)))
-		return -EFAULT;
-	first = OZ_MAX_EVTS - ix;
-	if (first > hdr.count)
-		first = hdr.count;
-	if (first) {
-		int sz = first*sizeof(struct oz_event);
-		void __user *p = (void __user *)lst->evts;
-		if (copy_to_user(p, &g_events[ix], sz))
-			return -EFAULT;
-		if (hdr.count > first) {
-			p = (void __user *)&lst->evts[first];
-			sz = (hdr.count-first)*sizeof(struct oz_event);
-			if (copy_to_user(p, g_events, sz))
-				return -EFAULT;
-		}
+	unsigned long irqstate;
+	oz_trace("Clearing events\n");
+	spin_lock_irqsave(&dev->lock, irqstate);
+	dev->evt_in = dev->evt_out = 0;
+	dev->missed_events = 0;
+	spin_unlock_irqrestore(&dev->lock, irqstate);
+}
+#ifdef CONFIG_DEBUG_FS
+/*------------------------------------------------------------------------------
+ * Context: process
+ */
+int oz_events_open(struct inode *inode, struct file *filp)
+{
+	oz_trace("oz_evt_open()\n");
+	oz_trace("Open flags: 0x%x\n", filp->f_flags);
+	if (atomic_add_return(1, &g_evtdev.users) == 1) {
+		oz_events_clear(&g_evtdev);
+		return nonseekable_open(inode, filp);
+	} else {
+		atomic_dec(&g_evtdev.users);
+		return -EBUSY;
 	}
-	ix += hdr.count;
-	if (ix >= OZ_MAX_EVTS)
-		ix -= OZ_MAX_EVTS;
-	g_evt_out = ix;
+}
+/*------------------------------------------------------------------------------
+ * Context: process
+ */
+int oz_events_release(struct inode *inode, struct file *filp)
+{
+	oz_events_clear(&g_evtdev);
+	atomic_dec(&g_evtdev.users);
+	g_evt_mask = 0;
+	oz_trace("oz_evt_release()\n");
 	return 0;
 }
 /*------------------------------------------------------------------------------
  * Context: process
  */
-void oz_events_clear(void)
+ssize_t oz_events_read(struct file *filp, char __user *buf, size_t count,
+		loff_t *fpos)
 {
-	unsigned long irqstate;
-	spin_lock_irqsave(&g_eventlock, irqstate);
-	g_evt_in = g_evt_out = 0;
-	g_missed_events = 0;
-	spin_unlock_irqrestore(&g_eventlock, irqstate);
+	struct oz_evtdev *dev = &g_evtdev;
+	int rc = 0;
+	int nb_evts = count / sizeof(struct oz_event);
+	int n;
+	int sz;
+
+	n = dev->evt_in - dev->evt_out;
+	if (n < 0)
+		n += OZ_MAX_EVTS;
+	if (nb_evts > n)
+		nb_evts = n;
+	if (nb_evts == 0)
+		goto out;
+	n = OZ_MAX_EVTS - dev->evt_out;
+	if (n > nb_evts)
+		n = nb_evts;
+	sz = n * sizeof(struct oz_event);
+	if (copy_to_user(buf, &dev->evts[dev->evt_out], sz)) {
+		rc = -EFAULT;
+		goto out;
+	}
+	if (n == nb_evts)
+		goto out2;
+	n = nb_evts - n;
+	if (copy_to_user(buf + sz, dev->evts, n * sizeof(struct oz_event))) {
+		rc = -EFAULT;
+		goto out;
+	}
+out2:
+	dev->evt_out = (dev->evt_out + nb_evts) & (OZ_MAX_EVTS - 1);
+	rc = nb_evts * sizeof(struct oz_event);
+out:
+	return rc;
 }
-#endif /* WANT_EVENT_TRACE */
+/*------------------------------------------------------------------------------
+ */
+const struct file_operations oz_events_fops = {
+	.owner =	THIS_MODULE,
+	.open =		oz_events_open,
+	.release =	oz_events_release,
+	.read =		oz_events_read,
+};
+/*------------------------------------------------------------------------------
+ * Context: process
+ */
+void oz_debugfs_init(void)
+{
+	struct dentry *parent;
 
+	parent = debugfs_create_dir("ozwpan", NULL);
+	if (parent  == NULL) {
+		oz_trace("Failed to create debugfs directory ozmo\n");
+		return;
+	} else {
+		g_evtdev.root_dir = parent;
+		if (debugfs_create_file("events", S_IRUSR, parent, NULL,
+						&oz_events_fops) == NULL)
+			oz_trace("Failed to create file ozmo/events\n");
+		if (debugfs_create_x32("event_mask", S_IRUSR | S_IWUSR, parent,
+							&g_evt_mask) == NULL)
+			oz_trace("Failed to create file ozmo/event_mask\n");
+	}
+}
+/*------------------------------------------------------------------------------
+ * Context: process
+ */
+void oz_debugfs_remove(void)
+{
+	debugfs_remove_recursive(g_evtdev.root_dir);
+}
+#endif /* CONFIG_DEBUG_FS */
+#endif /* WANT_EVENT_TRACE */
diff --git a/drivers/staging/ozwpan/ozevent.h b/drivers/staging/ozwpan/ozevent.h
index f033d014c6f..32f6f9859c4 100644
--- a/drivers/staging/ozwpan/ozevent.h
+++ b/drivers/staging/ozwpan/ozevent.h
@@ -9,23 +9,24 @@
 #include "ozeventdef.h"
 
 #ifdef WANT_EVENT_TRACE
-extern unsigned long g_evt_mask;
+extern u32 g_evt_mask;
 void oz_event_init(void);
 void oz_event_term(void);
 void oz_event_log2(u8 evt, u8 ctx1, u16 ctx2, void *ctx3, unsigned ctx4);
+void oz_debugfs_init(void);
+void oz_debugfs_remove(void);
 #define oz_event_log(__evt, __ctx1, __ctx2, __ctx3, __ctx4) \
 	do { \
 		if ((1<<(__evt)) & g_evt_mask) \
 			oz_event_log2(__evt, __ctx1, __ctx2, __ctx3, __ctx4); \
 	} while (0)
-int oz_events_copy(struct oz_evtlist __user *lst);
-void oz_events_clear(void);
+
 #else
 #define oz_event_init()
 #define oz_event_term()
 #define oz_event_log(__evt, __ctx1, __ctx2, __ctx3, __ctx4)
-#define oz_events_copy(__lst)
-#define oz_events_clear()
+#define oz_debugfs_init()
+#define oz_debugfs_remove()
 #endif /* WANT_EVENT_TRACE */
 
 #endif /* _OZEVENT_H */
diff --git a/drivers/staging/ozwpan/ozeventdef.h b/drivers/staging/ozwpan/ozeventdef.h
index a880288bab1..4b938981671 100644
--- a/drivers/staging/ozwpan/ozeventdef.h
+++ b/drivers/staging/ozwpan/ozeventdef.h
@@ -29,19 +29,12 @@
 #define OZ_EVT_DEBUG		20
 
 struct oz_event {
-	unsigned long jiffies;
-	unsigned char evt;
-	unsigned char ctx1;
-	unsigned short ctx2;
-	void *ctx3;
-	unsigned ctx4;
-};
-
-#define OZ_EVT_LIST_SZ	64
-struct oz_evtlist {
-	int count;
-	int missed;
-	struct oz_event evts[OZ_EVT_LIST_SZ];
+	__u32 jiffies;
+	__u8 evt;
+	__u8 ctx1;
+	__u16 ctx2;
+	__u32 ctx3;
+	__u32 ctx4;
 };
 
 #endif /* _OZEVENTDEF_H */
diff --git a/drivers/staging/ozwpan/ozmain.c b/drivers/staging/ozwpan/ozmain.c
index aaf2ccc0bcf..7579645d642 100644
--- a/drivers/staging/ozwpan/ozmain.c
+++ b/drivers/staging/ozwpan/ozmain.c
@@ -33,6 +33,9 @@ static int __init ozwpan_init(void)
 	oz_protocol_init(g_net_dev);
 	oz_app_enable(OZ_APPID_USB, 1);
 	oz_apps_init();
+#ifdef CONFIG_DEBUG_FS
+	oz_debugfs_init();
+#endif
 	return 0;
 }
 /*------------------------------------------------------------------------------
@@ -44,6 +47,9 @@ static void __exit ozwpan_exit(void)
 	oz_apps_term();
 	oz_cdev_deregister();
 	oz_event_term();
+#ifdef CONFIG_DEBUG_FS
+	oz_debugfs_remove();
+#endif
 }
 /*------------------------------------------------------------------------------
  */
@@ -53,6 +59,6 @@ module_exit(ozwpan_exit);
 
 MODULE_AUTHOR("Chris Kelly");
 MODULE_DESCRIPTION("Ozmo Devices USB over WiFi hcd driver");
-MODULE_VERSION("1.0.8");
+MODULE_VERSION("1.0.9");
 MODULE_LICENSE("GPL");