[PATCH 2/3] usb: gadget: file_storage: Make CD-ROM emulation work with Mac OS-X

From: Roger Quadros
Date: Wed Mar 09 2011 - 07:19:18 EST


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.

Signed-off-by: Roger Quadros <roger.quadros@xxxxxxxxx>
---
drivers/usb/gadget/file_storage.c | 32 +++++++++++++++++++-------------
1 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c
index a6eacb5..753ac94 100644
--- a/drivers/usb/gadget/file_storage.c
+++ b/drivers/usb/gadget/file_storage.c
@@ -1696,6 +1696,8 @@ static int do_read_toc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
int msf = fsg->cmnd[1] & 0x02;
int start_track = fsg->cmnd[6];
u8 *buf = (u8 *) bh->buf;
+ u8 format;
+ int ret;

if ((fsg->cmnd[1] & ~0x02) != 0 || /* Mask away MSF */
start_track > 1) {
@@ -1703,18 +1705,22 @@ static int do_read_toc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
return -EINVAL;
}

- memset(buf, 0, 20);
- buf[1] = (20-2); /* TOC data length */
- buf[2] = 1; /* First track number */
- buf[3] = 1; /* Last track number */
- buf[5] = 0x16; /* Data track, copying allowed */
- buf[6] = 0x01; /* Only track is number 1 */
- store_cdrom_address(&buf[8], msf, 0);
+ /*
+ * 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.
+ */
+ format = (fsg->cmnd[9] >> 6) & 0x3;
+ if (format == 0)
+ format = fsg->cmnd[2] & 0xf; /* new style MMC-2 */
+
+ ret = fsg_get_toc(curlun, msf, format, buf);
+ if (ret < 0) {
+ curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+ return -EINVAL;
+ }
+ return ret;

- 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;
}


@@ -2486,7 +2492,7 @@ static int do_scsi_command(struct fsg_dev *fsg)
goto unknown_cmnd;
fsg->data_size_from_cmnd = get_unaligned_be16(&fsg->cmnd[7]);
if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
- (7<<6) | (1<<1), 1,
+ (0xf<<6) | (1<<1), 1,
"READ TOC")) == 0)
reply = do_read_toc(fsg, bh);
break;
--
1.6.0.4

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