[media] v4l2-ioctl.c: v4l2-ioctl: add debug and callback/offset functionality

Add the necessary plumbing to make it possible to replace the switch by a
table driven implementation.

The ioctls ops can either be called directly, or by calling a small function
that does some additional work if needed.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/v4l2-ioctl.c

@@ -396,12 +396,22 @@ struct v4l2_ioctl_info {
 	unsigned int ioctl;
 	u32 flags;
 	const char * const name;
+	union {
+		u32 offset;
+		int (*func)(const struct v4l2_ioctl_ops *ops,
+				struct file *file, void *fh, void *p);
+	};
+	void (*debug)(const void *arg, bool write_only);
 };
 
 /* This control needs a priority check */
 #define INFO_FL_PRIO	(1 << 0)
 /* This control can be valid if the filehandle passes a control handler. */
 #define INFO_FL_CTRL	(1 << 1)
+/* This is a standard ioctl, no need for special code */
+#define INFO_FL_STD	(1 << 2)
+/* This is ioctl has its own function */
+#define INFO_FL_FUNC	(1 << 3)
 /* Zero struct from after the field to the end */
 #define INFO_FL_CLEAR(v4l2_struct, field)			\
 	((offsetof(struct v4l2_struct, field) +			\
@@ -414,6 +424,24 @@ struct v4l2_ioctl_info {
 	.name = #_ioctl,					\
 }
 
+#define IOCTL_INFO_STD(_ioctl, _vidioc, _debug, _flags)			\
+	[_IOC_NR(_ioctl)] = {						\
+		.ioctl = _ioctl,					\
+		.flags = _flags | INFO_FL_STD,				\
+		.name = #_ioctl,					\
+		.offset = offsetof(struct v4l2_ioctl_ops, _vidioc),	\
+		.debug = _debug,					\
+	}
+
+#define IOCTL_INFO_FNC(_ioctl, _func, _debug, _flags)			\
+	[_IOC_NR(_ioctl)] = {						\
+		.ioctl = _ioctl,					\
+		.flags = _flags | INFO_FL_FUNC,				\
+		.name = #_ioctl,					\
+		.func = _func,						\
+		.debug = _debug,					\
+	}
+
 static struct v4l2_ioctl_info v4l2_ioctls[] = {
 	IOCTL_INFO(VIDIOC_QUERYCAP, 0),
 	IOCTL_INFO(VIDIOC_ENUM_FMT, INFO_FL_CLEAR(v4l2_fmtdesc, type)),
@@ -512,7 +540,7 @@ bool v4l2_is_known_ioctl(unsigned int cmd)
    external ioctl messages as well as internal V4L ioctl */
 void v4l_printk_ioctl(unsigned int cmd)
 {
-	char *dir, *type;
+	const char *dir, *type;
 
 	switch (_IOC_TYPE(cmd)) {
 	case 'd':
@@ -523,10 +551,11 @@ void v4l_printk_ioctl(unsigned int cmd)
 			type = "v4l2";
 			break;
 		}
-		printk("%s", v4l2_ioctls[_IOC_NR(cmd)].name);
+		pr_cont("%s", v4l2_ioctls[_IOC_NR(cmd)].name);
 		return;
 	default:
 		type = "unknown";
+		break;
 	}
 
 	switch (_IOC_DIR(cmd)) {
@@ -536,7 +565,7 @@ void v4l_printk_ioctl(unsigned int cmd)
 	case _IOC_READ | _IOC_WRITE: dir = "rw"; break;
 	default:                     dir = "*ERR*"; break;
 	}
-	printk("%s ioctl '%c', dir=%s, #%d (0x%08x)",
+	pr_cont("%s ioctl '%c', dir=%s, #%d (0x%08x)",
 		type, _IOC_TYPE(cmd), dir, _IOC_NR(cmd), cmd);
 }
 EXPORT_SYMBOL(v4l_printk_ioctl);
@@ -546,6 +575,9 @@ static long __video_do_ioctl(struct file *file,
 {
 	struct video_device *vfd = video_devdata(file);
 	const struct v4l2_ioctl_ops *ops = vfd->ioctl_ops;
+	bool write_only = false;
+	struct v4l2_ioctl_info default_info;
+	const struct v4l2_ioctl_info *info;
 	void *fh = file->private_data;
 	struct v4l2_fh *vfh = NULL;
 	int use_fh_prio = 0;
@@ -563,23 +595,40 @@ static long __video_do_ioctl(struct file *file,
 	}
 
 	if (v4l2_is_known_ioctl(cmd)) {
-		struct v4l2_ioctl_info *info = &v4l2_ioctls[_IOC_NR(cmd)];
+		info = &v4l2_ioctls[_IOC_NR(cmd)];
 
 	        if (!test_bit(_IOC_NR(cmd), vfd->valid_ioctls) &&
 		    !((info->flags & INFO_FL_CTRL) && vfh && vfh->ctrl_handler))
-			return -ENOTTY;
+			goto done;
 
 		if (use_fh_prio && (info->flags & INFO_FL_PRIO)) {
 			ret = v4l2_prio_check(vfd->prio, vfh->prio);
 			if (ret)
-				return ret;
+				goto done;
 		}
+	} else {
+		default_info.ioctl = cmd;
+		default_info.flags = 0;
+		default_info.debug = NULL;
+		info = &default_info;
 	}
 
-	if ((vfd->debug & V4L2_DEBUG_IOCTL) &&
-				!(vfd->debug & V4L2_DEBUG_IOCTL_ARG)) {
+	write_only = _IOC_DIR(cmd) == _IOC_WRITE;
+	if (info->debug && write_only && vfd->debug > V4L2_DEBUG_IOCTL) {
 		v4l_print_ioctl(vfd->name, cmd);
-		printk(KERN_CONT "\n");
+		pr_cont(": ");
+		info->debug(arg, write_only);
+	}
+	if (info->flags & INFO_FL_STD) {
+		typedef int (*vidioc_op)(struct file *file, void *fh, void *p);
+		const void *p = vfd->ioctl_ops;
+		const vidioc_op *vidioc = p + info->offset;
+
+		ret = (*vidioc)(file, fh, arg);
+		goto done;
+	} else if (info->flags & INFO_FL_FUNC) {
+		ret = info->func(ops, file, fh, arg);
+		goto done;
 	}
 
 	switch (cmd) {
@@ -2101,10 +2150,26 @@ static long __video_do_ioctl(struct file *file,
 		break;
 	} /* switch */
 
-	if (vfd->debug & V4L2_DEBUG_IOCTL_ARG) {
-		if (ret < 0) {
+done:
+	if (vfd->debug) {
+		if (write_only && vfd->debug > V4L2_DEBUG_IOCTL) {
+			if (ret < 0)
+				printk(KERN_DEBUG "%s: error %ld\n",
+					video_device_node_name(vfd), ret);
+			return ret;
+		}
 		v4l_print_ioctl(vfd->name, cmd);
-			printk(KERN_CONT " error %ld\n", ret);
+		if (ret < 0)
+			pr_cont(": error %ld\n", ret);
+		else if (vfd->debug == V4L2_DEBUG_IOCTL)
+			pr_cont("\n");
+		else if (!info->debug)
+			return ret;
+		else if (_IOC_DIR(cmd) == _IOC_NONE)
+			info->debug(arg, write_only);
+		else {
+			pr_cont(": ");
+			info->debug(arg, write_only);
 		}
 	}