Messages in this thread | | | Date | Wed, 09 Mar 2011 16:41:01 +0300 | From | Sergei Shtylyov <> | Subject | Re: [PATCH 1/3] usb: gadget: storage: Add fsg_get_toc helper |
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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
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