ALSA: rawmidi: Add ioctl callback to snd_rawmidi_global_ops

A new callback, ioctl, is added to snd_rawmidi_global_ops for allowing
the driver to deal with the own ioctls.  This is another preparation
patch for the upcoming UMP support.
Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-3-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/rawmidi.h

@@ -47,6 +47,8 @@ struct snd_rawmidi_global_ops {
 	int (*dev_unregister) (struct snd_rawmidi * rmidi);
 	void (*get_port_info)(struct snd_rawmidi *rmidi, int number,
 			      struct snd_seq_port_info *info);
+	long (*ioctl)(struct snd_rawmidi *rmidi, unsigned int cmd,
+		      void __user *argp);
 };
 
 struct snd_rawmidi_runtime {

sound/core/rawmidi.c

@@ -893,6 +893,7 @@ static int snd_rawmidi_ioctl_status64(struct snd_rawmidi_file *rfile,
 static long snd_rawmidi_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct snd_rawmidi_file *rfile;
+	struct snd_rawmidi *rmidi;
 	void __user *argp = (void __user *)arg;
 
 	rfile = file->private_data;
@@ -984,8 +985,10 @@ static long snd_rawmidi_ioctl(struct file *file, unsigned int cmd, unsigned long
 		}
 	}
 	default:
-		rmidi_dbg(rfile->rmidi,
-			  "rawmidi: unknown command = 0x%x\n", cmd);
+		rmidi = rfile->rmidi;
+		if (rmidi->ops && rmidi->ops->ioctl)
+			return rmidi->ops->ioctl(rmidi, cmd, argp);
+		rmidi_dbg(rmidi, "rawmidi: unknown command = 0x%x\n", cmd);
 	}
 	return -ENOTTY;
 }