[PATCH 5.18 0699/1095] usb: gadget: f_mass_storage: Make CD-ROM emulation works with Windows OS

Greg Kroah-Hartman
2022-08-15T21:52:14Z

From: Neal Liu <neal_liu@aspeedtech.com>

[ Upstream commit 3b91edd624ab1ab694deef513a45eb9e9d49d75f ]

Add read TOC with format 1 to support CD-ROM emulation with
Windows OS.
This patch is tested on Windows OS Server 2019.

Fixes: 89ada0fe669a ("usb: gadget: f_mass_storage: Make CD-ROM emulation work with Mac OS-X")
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Neal Liu <neal_liu@aspeedtech.com>
Link: https://lore.kernel.org/r/20220628021436.3252262-1-neal_liu@aspeedtech.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/gadget/function/f_mass_storage.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 3a77bca0ebe1..e884f295504f 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -1192,13 +1192,14 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
u8 format;
int i, len;

+ format = common->cmnd[2] & 0xf;
+
if ((common->cmnd[1] & ~0x02) != 0 || /* Mask away MSF */
- start_track > 1) {
+ (start_track > 1 && format != 0x1)) {
curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
return -EINVAL;
}

- format = common->cmnd[2] & 0xf;
/*
* Check if CDB is old style SFF-8020i
* i.e. format is in 2 MSBs of byte 9
@@ -1208,8 +1209,8 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
format = (common->cmnd[9] >> 6) & 0x3;

switch (format) {
- case 0:
- /* Formatted TOC */
+ case 0: /* Formatted TOC */
+ case 1: /* Multi-session info */
len = 4 + 2*8; /* 4 byte header + 2 descriptors */
memset(buf, 0, len);
buf[1] = len - 2; /* TOC Length excludes length field */
@@ -1250,7 +1251,7 @@ static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
return len;

default:
- /* Multi-session, PMA, ATIP, CD-TEXT not supported/required */
+ /* PMA, ATIP, CD-TEXT not supported/required */
curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
return -EINVAL;
}
--
2.35.1