[PATCH 0/3] usb: gadget: storage: Make CD-ROM emulation work with Mac OS-X

[PATCH 0/3] usb: gadget: storage: Make CD-ROM emulation work with Mac OS-X

[Roger Quadros]

Hi,

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.

The first patch introduces a fsg_get_toc() helper which builds the
Table of Contents (TOC) that can be used for the READ_TOC command.
The remaining two patches simply make file_storage gadget and mass_storage
gadget use the new helper function.

---
Roger Quadros (3):
  usb: gadget: storage: Add fsg_get_toc helper
  usb: gadget: file_storage: Make CD-ROM emulation work with Mac OS-X
  usb: gadget: f_mass_storage: Make CD-ROM emulation work with Mac OS-X

 drivers/usb/gadget/f_mass_storage.c |   31 ++++++++------
 drivers/usb/gadget/file_storage.c   |   32 ++++++++------
 drivers/usb/gadget/storage_common.c |   79 +++++++++++++++++++++++++++++++++++
 3 files changed, 116 insertions(+), 26 deletions(-)

[PATCH 1/3] usb: gadget: storage: Add fsg_get_toc helper

[Roger Quadros]

fsg_get_toc can be used by both storage gadgets to build a CD-ROM
Table of Contents which can be used as data for READ_TOC command.
Currently fsg_get_toc supports two TOC formats, i.e.
format 0: Formatted TOC and format 2: Raw TOC.

Raw TOC is required for CD-ROM emulation to work with Mac OS-X.

Signed-off-by: Roger Quadros <roger.quadros@nokia.com>
---
 drivers/usb/gadget/storage_common.c |   79 +++++++++++++++++++++++++++++++++++
 1 files changed, 79 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
index b015561..ffad1d9 100644
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -655,6 +655,85 @@ static void store_cdrom_address(u8 *dest, int msf, u32 addr)
 	}
 }
 
+/*
+ * put_toc() - Builds a TOC with required format @format.
+ * @curlun: The LUN for which the TOC has to be built
+ * @msf: Min Sec Frame format or LBA format for address
+ * @format: TOC format code
+ * @buf: the buffer into which the TOC is built
+ *
+ * Builds a Table of Content which can be used as data for READ_TOC command.
+ * The TOC simulates a single session, single track CD-ROM mode 1 disc.
+ *
+ * Returns number of bytes written to @buf, -EINVAL if format not supported.
+ */
+static int fsg_get_toc(struct fsg_lun *curlun, int msf, int format, u8 *buf)
+{
+	switch (format) {
+	case 0:
+		/* Formatted TOC */
+		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);
+
+		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;
+		break;
+
+	case 2:
+		/* Raw TOC */
+		memset(buf, 0, 37);	/* Header + A0, A1 & A2 descriptors */
+		buf[1] = 37;		/* 4 + 3*11 */
+		buf[2] = 1;		/* First complete session */
+		buf[3] = 2;		/* Last complete session */
+
+		buf += 4;
+		/* A0 point */
+		buf[0] = 1;		/* Session number */
+		buf[1] = 0x16;		/* Data track, copying alowed */
+		/* 2 - Track number 0 -> TOC */
+		buf[3] = 0xA0;		/* Point A0 */
+		/* 4, 5, 6 - Min, sec, frame is zero */
+		/* 7 - zero */
+		buf[8] = 1;		/* Pmin: 1st track number */
+		/* 9 - disc type 0: CD-ROM/DA with 1st track in mode 1 */
+		/* 10 - pframe 0 */
+
+		buf += 11;
+		/* A1 point*/
+		buf[0] = 1;		/* Session number */
+		buf[1] = 0x16;		/* Data track, copying alowed */
+		/* 2 - Track number 0 -> TOC */
+		buf[3] = 0xA1;		/* Point A1 */
+		/* 4, 5, 6 - Min, sec, frame is zero */
+		/* 7, zero */
+		buf[8] = 1;		/* Pmin: last track number */
+		/* 9, 10 - pmin and pframe are 0 */
+
+		buf += 11;
+		/* A2 point*/
+		buf[0] = 1;		/* Session number */
+		buf[1] = 0x16;		/* Data track, copying alowed */
+		/* 2 - Track number 0 -> TOC */
+		buf[3] = 0xA2;		/* Point A2 */
+		/* 4, 5, 6 - Min, sec, frame is zero */
+		/* 7, 8, 9, 10 - zero, Pmin, Psec, Pframe of Lead out */
+		store_cdrom_address(&buf[7], msf, curlun->num_sectors);
+		return 37;
+		break;
+	default:
+		/* Multi-session, PMA, ATIP, CD-TEXT not supported/required */
+		return -EINVAL;
+		break;
+	}
+}
+
 
 /*-------------------------------------------------------------------------*/
 
-- 
1.6.0.4

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

[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 <roger.quadros@nokia.com>
---
 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

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

[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 <roger.quadros@nokia.com>
---
 drivers/usb/gadget/f_mass_storage.c |   31 ++++++++++++++++++-------------
 1 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index 6d8e533..d3fd60d 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -1315,6 +1315,8 @@ 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		ret;
 
 	if ((common->cmnd[1] & ~0x02) != 0 ||	/* Mask away MSF */
 			start_track > 1) {
@@ -1322,18 +1324,21 @@ 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 */
-	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 = (common->cmnd[9] >> 6) & 0x3;
+	if (format == 0)
+		format = common->cmnd[2] & 0xf;	/* new style MMC-2 */
 
-	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;
+	ret = fsg_get_toc(curlun, msf, format, buf);
+	if (ret < 0) {
+		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+		return -EINVAL;
+	}
+	return ret;
 }
 
 static int do_mode_sense(struct fsg_common *common, struct fsg_buffhd *bh)
@@ -2103,7 +2108,7 @@ 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);
-- 
1.6.0.4

Re: [PATCH 1/3] usb: gadget: storage: Add fsg_get_toc helper

[Sergei Shtylyov]

Hello.

On 09-03-2011 15:21, Roger Quadros wrote:

> fsg_get_toc can be used by both storage gadgets to build a CD-ROM
> Table of Contents which can be used as data for READ_TOC command.
> Currently fsg_get_toc supports two TOC formats, i.e.
> format 0: Formatted TOC and format 2: Raw TOC.

> Raw TOC is required for CD-ROM emulation to work with Mac OS-X.

> Signed-off-by: Roger Quadros<roger.quadros@nokia.com>
> ---
>   drivers/usb/gadget/storage_common.c |   79 +++++++++++++++++++++++++++++++++++
>   1 files changed, 79 insertions(+), 0 deletions(-)

> diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
> index b015561..ffad1d9 100644
> --- a/drivers/usb/gadget/storage_common.c
> +++ b/drivers/usb/gadget/storage_common.c
> @@ -655,6 +655,85 @@ static void store_cdrom_address(u8 *dest, int msf, u32 addr)
>   	}
>   }
>
> +/*

    The kerneldoc comments should start with "/**".

> + * put_toc() - Builds a TOC with required format @format.

    The function is called gsg_get_toc, isn't it?

> + * @curlun: The LUN for which the TOC has to be built
> + * @msf: Min Sec Frame format or LBA format for address
> + * @format: TOC format code
> + * @buf: the buffer into which the TOC is built
> + *
> + * Builds a Table of Content which can be used as data for READ_TOC command.
> + * The TOC simulates a single session, single track CD-ROM mode 1 disc.
> + *
> + * Returns number of bytes written to @buf, -EINVAL if format not supported.
> + */
> +static int fsg_get_toc(struct fsg_lun *curlun, int msf, int format, u8 *buf)
> +{
> +	switch (format) {
> +	case 0:
> +		/* Formatted TOC */
> +		memset(buf, 0, 20);
> +		buf[1] = (20-2);	/* TOC data length */

    Parens not needed here. And kernel style assumes putting spacves around 
operators.

> +		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 20;
> +		break;
> +
> +	case 2:
> +		/* Raw TOC */
> +		memset(buf, 0, 37);	/* Header + A0, A1&  A2 descriptors */
> +		buf[1] = 37;		/* 4 + 3*11 */
> +		buf[2] = 1;		/* First complete session */
> +		buf[3] = 2;		/* Last complete session */
> +
> +		buf += 4;
> +		/* A0 point */
> +		buf[0] = 1;		/* Session number */
> +		buf[1] = 0x16;		/* Data track, copying alowed */
> +		/* 2 - Track number 0 ->  TOC */
> +		buf[3] = 0xA0;		/* Point A0 */
> +		/* 4, 5, 6 - Min, sec, frame is zero */
> +		/* 7 - zero */
> +		buf[8] = 1;		/* Pmin: 1st track number */
> +		/* 9 - disc type 0: CD-ROM/DA with 1st track in mode 1 */
> +		/* 10 - pframe 0 */
> +
> +		buf += 11;
> +		/* A1 point*/
> +		buf[0] = 1;		/* Session number */
> +		buf[1] = 0x16;		/* Data track, copying alowed */
> +		/* 2 - Track number 0 ->  TOC */
> +		buf[3] = 0xA1;		/* Point A1 */
> +		/* 4, 5, 6 - Min, sec, frame is zero */
> +		/* 7, zero */
> +		buf[8] = 1;		/* Pmin: last track number */
> +		/* 9, 10 - pmin and pframe are 0 */

    The above code is repetitive -- might be worth factoring out into a function.

> +
> +		buf += 11;
> +		/* A2 point*/
> +		buf[0] = 1;		/* Session number */
> +		buf[1] = 0x16;		/* Data track, copying alowed */
> +		/* 2 - Track number 0 ->  TOC */
> +		buf[3] = 0xA2;		/* Point A2 */
> +		/* 4, 5, 6 - Min, sec, frame is zero */
> +		/* 7, 8, 9, 10 - zero, Pmin, Psec, Pframe of Lead out */
> +		store_cdrom_address(&buf[7], msf, curlun->num_sectors);
> +		return 37;
> +		break;
> +	default:
> +		/* Multi-session, PMA, ATIP, CD-TEXT not supported/required */
> +		return -EINVAL;
> +		break;
> +	}
> +}
> +

    OK, but where this function is called from?

WBR, Sergei

Re: [PATCH 1/3] usb: gadget: storage: Add fsg_get_toc helper

[Roger Quadros]

Hi,

On 03/09/2011 03:41 PM, ext Sergei Shtylyov wrote:
> Hello.
>
>> --- a/drivers/usb/gadget/storage_common.c
>> +++ b/drivers/usb/gadget/storage_common.c
>> @@ -655,6 +655,85 @@ static void store_cdrom_address(u8 *dest, int msf, u32 addr)
>> }
>> }
>>
>> +/*
>
> The kerneldoc comments should start with "/**".

OK.

>
>> + * put_toc() - Builds a TOC with required format @format.
>
> The function is called gsg_get_toc, isn't it?

Yes :). My initial version was named put_toc(). will correct it.

>
>> + * @curlun: The LUN for which the TOC has to be built
>> + * @msf: Min Sec Frame format or LBA format for address
>> + * @format: TOC format code
>> + * @buf: the buffer into which the TOC is built
>> + *
>> + * Builds a Table of Content which can be used as data for READ_TOC command.
>> + * The TOC simulates a single session, single track CD-ROM mode 1 disc.
>> + *
>> + * Returns number of bytes written to @buf, -EINVAL if format not supported.
>> + */
>> +static int fsg_get_toc(struct fsg_lun *curlun, int msf, int format, u8 *buf)
>> +{
>> + switch (format) {
>> + case 0:
>> + /* Formatted TOC */
>> + memset(buf, 0, 20);
>> + buf[1] = (20-2); /* TOC data length */
>
> Parens not needed here. And kernel style assumes putting spacves around operators.

I copied case 0: code from file_storage.c. But will correct it.
>
>> + 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 20;
>> + break;
>> +
>> + case 2:
>> + /* Raw TOC */
>> + memset(buf, 0, 37); /* Header + A0, A1& A2 descriptors */
>> + buf[1] = 37; /* 4 + 3*11 */
>> + buf[2] = 1; /* First complete session */
>> + buf[3] = 2; /* Last complete session */
>> +
>> + buf += 4;
>> + /* A0 point */
>> + buf[0] = 1; /* Session number */
>> + buf[1] = 0x16; /* Data track, copying alowed */
>> + /* 2 - Track number 0 -> TOC */
>> + buf[3] = 0xA0; /* Point A0 */
>> + /* 4, 5, 6 - Min, sec, frame is zero */
>> + /* 7 - zero */
>> + buf[8] = 1; /* Pmin: 1st track number */
>> + /* 9 - disc type 0: CD-ROM/DA with 1st track in mode 1 */
>> + /* 10 - pframe 0 */
>> +
>> + buf += 11;
>> + /* A1 point*/
>> + buf[0] = 1; /* Session number */
>> + buf[1] = 0x16; /* Data track, copying alowed */
>> + /* 2 - Track number 0 -> TOC */
>> + buf[3] = 0xA1; /* Point A1 */
>> + /* 4, 5, 6 - Min, sec, frame is zero */
>> + /* 7, zero */
>> + buf[8] = 1; /* Pmin: last track number */
>> + /* 9, 10 - pmin and pframe are 0 */
>
> The above code is repetitive -- might be worth factoring out into a function.
>
I would leave it as it is as nobody else would use the function.

> OK, but where this function is called from?
>
from file_storage.c and f_mass_storage.c in the next two patches of this series.

-- 
regards,
-roger

Re: [PATCH 1/3] usb: gadget: storage: Add fsg_get_toc helper

[Alan Stern]

On Wed, 9 Mar 2011, Roger Quadros wrote:

> fsg_get_toc can be used by both storage gadgets to build a CD-ROM
> Table of Contents which can be used as data for READ_TOC command.
> Currently fsg_get_toc supports two TOC formats, i.e.
> format 0: Formatted TOC and format 2: Raw TOC.
> 
> Raw TOC is required for CD-ROM emulation to work with Mac OS-X.

In addition to the things Sergei mentioned...

> +/*
> + * put_toc() - Builds a TOC with required format @format.
> + * @curlun: The LUN for which the TOC has to be built
> + * @msf: Min Sec Frame format or LBA format for address
> + * @format: TOC format code
> + * @buf: the buffer into which the TOC is built
> + *
> + * Builds a Table of Content which can be used as data for READ_TOC command.
> + * The TOC simulates a single session, single track CD-ROM mode 1 disc.
> + *
> + * Returns number of bytes written to @buf, -EINVAL if format not supported.
> + */
> +static int fsg_get_toc(struct fsg_lun *curlun, int msf, int format, u8 *buf)
> +{
> +	switch (format) {
> +	case 0:
> +		/* Formatted TOC */
> +		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);
> +
> +		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;
> +		break;
> +
> +	case 2:
> +		/* Raw TOC */
> +		memset(buf, 0, 37);	/* Header + A0, A1 & A2 descriptors */
> +		buf[1] = 37;		/* 4 + 3*11 */

There's no reason to do it this way.  The compiler is a lot better than 
you are at addition.  Just put 4 + 3*11 in the assignment statement, 
and in the comment explain what the numbers mean.

> +		buf[2] = 1;		/* First complete session */
> +		buf[3] = 2;		/* Last complete session */
> +
> +		buf += 4;
> +		/* A0 point */
> +		buf[0] = 1;		/* Session number */
> +		buf[1] = 0x16;		/* Data track, copying alowed */
> +		/* 2 - Track number 0 -> TOC */
> +		buf[3] = 0xA0;		/* Point A0 */
> +		/* 4, 5, 6 - Min, sec, frame is zero */
> +		/* 7 - zero */
> +		buf[8] = 1;		/* Pmin: 1st track number */
> +		/* 9 - disc type 0: CD-ROM/DA with 1st track in mode 1 */
> +		/* 10 - pframe 0 */
> +
> +		buf += 11;
> +		/* A1 point*/
> +		buf[0] = 1;		/* Session number */
> +		buf[1] = 0x16;		/* Data track, copying alowed */
> +		/* 2 - Track number 0 -> TOC */
> +		buf[3] = 0xA1;		/* Point A1 */
> +		/* 4, 5, 6 - Min, sec, frame is zero */
> +		/* 7, zero */
> +		buf[8] = 1;		/* Pmin: last track number */
> +		/* 9, 10 - pmin and pframe are 0 */
> +
> +		buf += 11;
> +		/* A2 point*/
> +		buf[0] = 1;		/* Session number */
> +		buf[1] = 0x16;		/* Data track, copying alowed */
> +		/* 2 - Track number 0 -> TOC */
> +		buf[3] = 0xA2;		/* Point A2 */
> +		/* 4, 5, 6 - Min, sec, frame is zero */
> +		/* 7, 8, 9, 10 - zero, Pmin, Psec, Pframe of Lead out */
> +		store_cdrom_address(&buf[7], msf, curlun->num_sectors);

These things could be put into a loop, instead of a separate function.

> +		return 37;

It might be a good idea to use a variable instead of having all these 
"37"s floating around.  It would make future updates more reliable.

> +		break;
> +	default:
> +		/* Multi-session, PMA, ATIP, CD-TEXT not supported/required */
> +		return -EINVAL;
> +		break;
> +	}
> +}

Alan Stern

Re: [PATCH 1/3] usb: gadget: storage: Add fsg_get_toc helper

[Roger Quadros]

On 03/09/2011 05:10 PM, ext Alan Stern wrote:

>> +	case 2:
>> +		/* Raw TOC */
>> +		memset(buf, 0, 37);	/* Header + A0, A1&  A2 descriptors */
>> +		buf[1] = 37;		/* 4 + 3*11 */
>
> There's no reason to do it this way.  The compiler is a lot better than
> you are at addition.  Just put 4 + 3*11 in the assignment statement,
> and in the comment explain what the numbers mean.

OK.

>
>> +		buf[2] = 1;		/* First complete session */
>> +		buf[3] = 2;		/* Last complete session */
>> +
>> +		buf += 4;
>> +		/* A0 point */
>> +		buf[0] = 1;		/* Session number */
>> +		buf[1] = 0x16;		/* Data track, copying alowed */
>> +		/* 2 - Track number 0 ->  TOC */
>> +		buf[3] = 0xA0;		/* Point A0 */
>> +		/* 4, 5, 6 - Min, sec, frame is zero */
>> +		/* 7 - zero */
>> +		buf[8] = 1;		/* Pmin: 1st track number */
>> +		/* 9 - disc type 0: CD-ROM/DA with 1st track in mode 1 */
>> +		/* 10 - pframe 0 */
>> +
>> +		buf += 11;
>> +		/* A1 point*/
>> +		buf[0] = 1;		/* Session number */
>> +		buf[1] = 0x16;		/* Data track, copying alowed */
>> +		/* 2 - Track number 0 ->  TOC */
>> +		buf[3] = 0xA1;		/* Point A1 */
>> +		/* 4, 5, 6 - Min, sec, frame is zero */
>> +		/* 7, zero */
>> +		buf[8] = 1;		/* Pmin: last track number */
>> +		/* 9, 10 - pmin and pframe are 0 */
>> +
>> +		buf += 11;
>> +		/* A2 point*/
>> +		buf[0] = 1;		/* Session number */
>> +		buf[1] = 0x16;		/* Data track, copying alowed */
>> +		/* 2 - Track number 0 ->  TOC */
>> +		buf[3] = 0xA2;		/* Point A2 */
>> +		/* 4, 5, 6 - Min, sec, frame is zero */
>> +		/* 7, 8, 9, 10 - zero, Pmin, Psec, Pframe of Lead out */
>> +		store_cdrom_address(&buf[7], msf, curlun->num_sectors);
>
> These things could be put into a loop, instead of a separate function.

Yes loop is better than function for this case.

>
>> +		return 37;
>
> It might be a good idea to use a variable instead of having all these
> "37"s floating around.  It would make future updates more reliable.

OK.

-- 
regards,
-roger

Re: [PATCH 1/3] usb: gadget: storage: Add fsg_get_toc helper

[Alan Stern]

On Wed, 9 Mar 2011, Roger Quadros wrote:

> fsg_get_toc can be used by both storage gadgets to build a CD-ROM
> Table of Contents which can be used as data for READ_TOC command.
> Currently fsg_get_toc supports two TOC formats, i.e.
> format 0: Formatted TOC and format 2: Raw TOC.
> 
> Raw TOC is required for CD-ROM emulation to work with Mac OS-X.
> 
> Signed-off-by: Roger Quadros <roger.quadros@nokia.com>
> ---
>  drivers/usb/gadget/storage_common.c |   79 +++++++++++++++++++++++++++++++++++
>  1 files changed, 79 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
> index b015561..ffad1d9 100644
> --- a/drivers/usb/gadget/storage_common.c
> +++ b/drivers/usb/gadget/storage_common.c
> @@ -655,6 +655,85 @@ static void store_cdrom_address(u8 *dest, int msf, u32 addr)
>  	}
>  }
>  
> +/*
> + * put_toc() - Builds a TOC with required format @format.
> + * @curlun: The LUN for which the TOC has to be built
> + * @msf: Min Sec Frame format or LBA format for address
> + * @format: TOC format code
> + * @buf: the buffer into which the TOC is built
> + *
> + * Builds a Table of Content which can be used as data for READ_TOC command.
> + * The TOC simulates a single session, single track CD-ROM mode 1 disc.
> + *
> + * Returns number of bytes written to @buf, -EINVAL if format not supported.
> + */
> +static int fsg_get_toc(struct fsg_lun *curlun, int msf, int format, u8 *buf)
> +{
> +	switch (format) {
> +	case 0:
> +		/* Formatted TOC */
> +		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);
> +
> +		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;
> +		break;
> +
> +	case 2:
> +		/* Raw TOC */
> +		memset(buf, 0, 37);	/* Header + A0, A1 & A2 descriptors */
> +		buf[1] = 37;		/* 4 + 3*11 */

According to the SFF8020i spec Table 128, TOC Data Length is 2 + 11 *
(number of descriptors returned).  But that's probably a misprint.

> +		buf[2] = 1;		/* First complete session */
> +		buf[3] = 2;		/* Last complete session */

According to the spec, for drives that do not support multi-session, 
the First session number should be equal to the Last session number.


On Wed, 9 Mar 2011, Roger Quadros wrote:

> 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@nokia.com>
> ---
>  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 */

The spec says: "Format field definition: When Format in Byte 2 is zero, 
then Byte 9 is used."  This logic does not follow that description.

Alan Stern

Re: [PATCH 1/3] usb: gadget: storage: Add fsg_get_toc helper

[Roger Quadros]

Hi,

On 03/09/2011 06:07 PM, ext Alan Stern wrote:
>> +	case 2:
>> +		/* Raw TOC */
>> +		memset(buf, 0, 37);	/* Header + A0, A1&  A2 descriptors */
>> +		buf[1] = 37;		/* 4 + 3*11 */
>
> According to the SFF8020i spec Table 128, TOC Data Length is 2 + 11 *
> (number of descriptors returned).  But that's probably a misprint.

It's probably right. I will fix it and verify if it works.
>
>> +		buf[2] = 1;		/* First complete session */
>> +		buf[3] = 2;		/* Last complete session */
>
> According to the spec, for drives that do not support multi-session,
> the First session number should be equal to the Last session number.
>
Right. good catch.

>
> On Wed, 9 Mar 2011, Roger Quadros wrote:
>
>> 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@nokia.com>
>> ---
>>   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 */
>
> The spec says: "Format field definition: When Format in Byte 2 is zero,
> then Byte 9 is used."  This logic does not follow that description.
>

Yes indeed. I'll fix all this in v2. Thanks for review.

-- 
regards,
-roger