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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/