[U-Boot] [PATCH 1/2] net: move ether_crc to tsec driver

[Simon Goldschmidt]

On Tue, Nov 27, 2018 at 4:19 AM Chris Packham <judge.packham at gmail.com> wrote:
>
> On Mon, Nov 26, 2018 at 9:12 PM Simon Goldschmidt
> <simon.k.r.goldschmidt at gmail.com> wrote:
> >
> > On Mon, Nov 26, 2018 at 9:00 AM Chris Packham <judge.packham at gmail.com> wrote:
> > >
> > > ether_crc was added to the core net code in commit 53a5c424bf86
> > > ("multicast tftp: RFC2090") so that other drivers could use it. However
> > > the only current user of it is tsec.c so move it there.
> > >
> > > Signed-off-by: Chris Packham <judge.packham at gmail.com>
> > > ---
> > >
> > >  drivers/net/tsec.c | 25 +++++++++++++++++++++++++
> > >  include/net.h      |  1 -
> > >  net/eth_legacy.c   | 24 ------------------------
> > >  3 files changed, 25 insertions(+), 25 deletions(-)
> > >
> > > diff --git a/drivers/net/tsec.c b/drivers/net/tsec.c
> > > index 03a46da2f8a1..9a4fab85e928 100644
> > > --- a/drivers/net/tsec.c
> > > +++ b/drivers/net/tsec.c
> > > @@ -80,6 +80,31 @@ static void tsec_configure_serdes(struct tsec_private *priv)
> > >
> > >  #ifdef CONFIG_MCAST_TFTP
> > >
> > > +/* the 'way' for ethernet-CRC-32. Spliced in from Linux lib/crc32.c
> > > + * and this is the ethernet-crc method needed for TSEC -- and perhaps
> > > + * some other adapter -- hash tables
> > > + */
> > > +#define CRCPOLY_LE 0xedb88320
> > > +static u32 ether_crc(size_t len, unsigned char const *p)
> >
> > I haven't checked, but can't we use lib/crc32.c for this? The
> > polynomial is the same...
> >
>
> Yes more than likely.  I erred on the side of not changing more than
> absolutely necessary. However given the fact that this code isn't
> currently run on any platform maybe that's too cautious.

A quick test shows me that a call to 'ether_crc(len, data)' can be
replaced by 'bitrev32(crc32_no_comp(~0, data, len))'.
Of course the code size increases as those files have tables (crc
table: 1K, bitrev table: 256 bytes).

Simon

>
> > > +{
> > > +       int i;
> > > +       u32 crc;
> > > +
> > > +       crc = ~0;
> > > +       while (len--) {
> > > +               crc ^= *p++;
> > > +               for (i = 0; i < 8; i++)
> > > +                       crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
> > > +       }
> > > +       /* an reverse the bits, cuz of way they arrive -- last-first */
> > > +       crc = (crc >> 16) | (crc << 16);
> > > +       crc = (crc >> 8 & 0x00ff00ff) | (crc << 8 & 0xff00ff00);
> > > +       crc = (crc >> 4 & 0x0f0f0f0f) | (crc << 4 & 0xf0f0f0f0);
> > > +       crc = (crc >> 2 & 0x33333333) | (crc << 2 & 0xcccccccc);
> > > +       crc = (crc >> 1 & 0x55555555) | (crc << 1 & 0xaaaaaaaa);
> >
> > Does lib/bitrev.c do this job?
> >
> > Regards,
> > Simon
> >
> > > +       return crc;
> > > +}
> > > +
> > >  /* CREDITS: linux gianfar driver, slightly adjusted... thanx. */
> > >
> > >  /* Set the appropriate hash bit for the given addr */
> > > diff --git a/include/net.h b/include/net.h
> > > index 51c099dae2e5..359bfb5ef69f 100644
> > > --- a/include/net.h
> > > +++ b/include/net.h
> > > @@ -289,7 +289,6 @@ const char *eth_get_name(void);             /* get name of current device */
> > >
> > >  #ifdef CONFIG_MCAST_TFTP
> > >  int eth_mcast_join(struct in_addr mcast_addr, int join);
> > > -u32 ether_crc(size_t len, unsigned char const *p);
> > >  #endif
> > >
> > >
> > > diff --git a/net/eth_legacy.c b/net/eth_legacy.c
> > > index 2a9caa3509b0..d2e16b8fa3da 100644
> > > --- a/net/eth_legacy.c
> > > +++ b/net/eth_legacy.c
> > > @@ -310,30 +310,6 @@ int eth_mcast_join(struct in_addr mcast_ip, int join)
> > >         return eth_current->mcast(eth_current, mcast_mac, join);
> > >  }
> > >
> > > -/* the 'way' for ethernet-CRC-32. Spliced in from Linux lib/crc32.c
> > > - * and this is the ethernet-crc method needed for TSEC -- and perhaps
> > > - * some other adapter -- hash tables
> > > - */
> > > -#define CRCPOLY_LE 0xedb88320
> > > -u32 ether_crc(size_t len, unsigned char const *p)
> > > -{
> > > -       int i;
> > > -       u32 crc;
> > > -       crc = ~0;
> > > -       while (len--) {
> > > -               crc ^= *p++;
> > > -               for (i = 0; i < 8; i++)
> > > -                       crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
> > > -       }
> > > -       /* an reverse the bits, cuz of way they arrive -- last-first */
> > > -       crc = (crc >> 16) | (crc << 16);
> > > -       crc = (crc >> 8 & 0x00ff00ff) | (crc << 8 & 0xff00ff00);
> > > -       crc = (crc >> 4 & 0x0f0f0f0f) | (crc << 4 & 0xf0f0f0f0);
> > > -       crc = (crc >> 2 & 0x33333333) | (crc << 2 & 0xcccccccc);
> > > -       crc = (crc >> 1 & 0x55555555) | (crc << 1 & 0xaaaaaaaa);
> > > -       return crc;
> > > -}
> > > -
> > >  #endif
> > >
> > >
> > > --
> > > 2.19.2
> > >
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