usb: gadget: f_mass_storage: Make CD-ROM emulation work with Mac OS-X

Mac OS-X expects CD-ROM TOC in raw format (i.e. format:2). It also
sends the READ_TOC CDB in old style SFF8020i format. i.e. 2 format bits
are encoded in MSBs of CDB byte 9.

This patch will enable CD-ROM emulation to work with Mac OS-X. Tested on
Mac OS X v10.6.3.
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Roger Quadros <roger.quadros@nokia.com>
Signed-off-by: Jack Pham <quic_jackp@quicinc.com>
Link: https://lore.kernel.org/r/20220124160150.19499-1-quic_jackp@quicinc.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/function/f_mass_storage.c

@@ -1188,6 +1188,8 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
 	int		msf = common->cmnd[1] & 0x02;
 	int		start_track = common->cmnd[6];
 	u8		*buf = (u8 *)bh->buf;
+	u8		format;
+	int		i, len;
 
 	if ((common->cmnd[1] & ~0x02) != 0 ||	/* Mask away MSF */
 			start_track > 1) {
@@ -1195,8 +1197,21 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
 		return -EINVAL;
 	}
 
-	memset(buf, 0, 20);
-	buf[1] = (20-2);		/* TOC data length */
+	format = common->cmnd[2] & 0xf;
+	/*
+	 * Check if CDB is old style SFF-8020i
+	 * i.e. format is in 2 MSBs of byte 9
+	 * Mac OS-X host sends us this.
+	 */
+	if (format == 0)
+		format = (common->cmnd[9] >> 6) & 0x3;
+
+	switch (format) {
+	case 0:
+		/* Formatted TOC */
+		len = 4 + 2*8;		/* 4 byte header + 2 descriptors */
+		memset(buf, 0, len);
+		buf[1] = len - 2;	/* TOC Length excludes length field */
 		buf[2] = 1;		/* First track number */
 		buf[3] = 1;		/* Last track number */
 		buf[5] = 0x16;		/* Data track, copying allowed */
@@ -1206,7 +1221,38 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
 		buf[13] = 0x16;		/* Lead-out track is data */
 		buf[14] = 0xAA;		/* Lead-out track number */
 		store_cdrom_address(&buf[16], msf, curlun->num_sectors);
-	return 20;
+		return len;
+
+	case 2:
+		/* Raw TOC */
+		len = 4 + 3*11;		/* 4 byte header + 3 descriptors */
+		memset(buf, 0, len);	/* Header + A0, A1 & A2 descriptors */
+		buf[1] = len - 2;	/* TOC Length excludes length field */
+		buf[2] = 1;		/* First complete session */
+		buf[3] = 1;		/* Last complete session */
+
+		buf += 4;
+		/* fill in A0, A1 and A2 points */
+		for (i = 0; i < 3; i++) {
+			buf[0] = 1;	/* Session number */
+			buf[1] = 0x16;	/* Data track, copying allowed */
+			/* 2 - Track number 0 ->  TOC */
+			buf[3] = 0xA0 + i; /* A0, A1, A2 point */
+			/* 4, 5, 6 - Min, sec, frame is zero */
+			buf[8] = 1;	/* Pmin: last track number */
+			buf += 11;	/* go to next track descriptor */
+		}
+		buf -= 11;		/* go back to A2 descriptor */
+
+		/* For A2, 7, 8, 9, 10 - zero, Pmin, Psec, Pframe of Lead out */
+		store_cdrom_address(&buf[7], msf, curlun->num_sectors);
+		return len;
+
+	default:
+		/* Multi-session, PMA, ATIP, CD-TEXT not supported/required */
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
 }
 
 static int do_mode_sense(struct fsg_common *common, struct fsg_buffhd *bh)
@@ -1944,7 +1990,7 @@ static int do_scsi_command(struct fsg_common *common)
 		common->data_size_from_cmnd =
 			get_unaligned_be16(&common->cmnd[7]);
 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
-				      (7<<6) | (1<<1), 1,
+				      (0xf<<6) | (3<<1), 1,
 				      "READ TOC");
 		if (reply == 0)
 			reply = do_read_toc(common, bh);