From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 348D1C433FE for ; Wed, 12 Jan 2022 20:06:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357271AbiALUGe (ORCPT ); Wed, 12 Jan 2022 15:06:34 -0500 Received: from netrider.rowland.org ([192.131.102.5]:51667 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1357331AbiALUFh (ORCPT ); Wed, 12 Jan 2022 15:05:37 -0500 Received: (qmail 243238 invoked by uid 1000); 12 Jan 2022 15:05:35 -0500 Date: Wed, 12 Jan 2022 15:05:35 -0500 From: Alan Stern To: Jack Pham Cc: Greg KH , Roger Quadros , Michal Nazarewicz , linux-usb@vger.kernel.org, Roger Quadros Subject: Re: [PATCH v2] usb: gadget: f_mass_storage: Make CD-ROM emulation work with Mac OS-X Message-ID: References: <20220110062359.5314-2-quic_jackp@quicinc.com> <20220110063030.12957-1-quic_jackp@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220110063030.12957-1-quic_jackp@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Sun, Jan 09, 2022 at 10:30:30PM -0800, Jack Pham wrote: > From: Roger Quadros > > 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 > Signed-off-by: Jack Pham > --- > v2: Removed Change-Id tag. > > drivers/usb/gadget/function/f_mass_storage.c | 73 +++++++++++++++++++++++----- > 1 file changed, 61 insertions(+), 12 deletions(-) > > diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c > index 73a28f8..1f7f4dd6 100644 > --- a/drivers/usb/gadget/function/f_mass_storage.c > +++ b/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) { > @@ -1195,18 +1197,65 @@ 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 */ > - 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); > + format = common->cmnd[2] & 0xf; Hmmm. According to this part later on: > @@ -1933,7 +1982,7 @@ 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) | (1<<1), 1, > "READ TOC"); common->cmnd[2] can never be anything other than 0. So this computation and the test immediately below are pointless -- unless you change the argument to check_command(). Alan Stern > + /* > + * 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); > + len -= 2; /* TOC Length excludes length field */ > + buf[1] = len; /* 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); > + > + 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 len; > + > + case 2: > + /* Raw TOC */ > + len = 4 + 3*11; /* 4 byte header + 3 descriptors */ > + memset(buf, 0, len); /* Header + A0, A1 & A2 descriptors */ > + len -= 2; /* TOC Length excludes length field */ > + buf[1] = len; /* TOC data length */ > + 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); > > - 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; > + > + 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) > @@ -1933,7 +1982,7 @@ 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) | (1<<1), 1, > "READ TOC"); > if (reply == 0) > reply = do_read_toc(common, bh); > -- > 2.7.4 >