[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@xxxxxxxxx>
---
 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

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