Re: [net PATCH 1/2] net: dsa: qca8k: fix inband mgmt for big-endian systems

From: Andrew Lunn
Date: Wed Oct 12 2022 - 08:30:03 EST


On Mon, Oct 10, 2022 at 02:44:46PM +0200, Christian Marangi wrote:
> On Mon, Oct 10, 2022 at 08:53:01PM +0200, Andrew Lunn wrote:
> > > /* Special struct emulating a Ethernet header */
> > > struct qca_mgmt_ethhdr {
> > > - u32 command; /* command bit 31:0 */
> > > - u32 seq; /* seq 63:32 */
> > > - u32 mdio_data; /* first 4byte mdio */
> > > + __le32 command; /* command bit 31:0 */
> > > + __le32 seq; /* seq 63:32 */
> > > + __le32 mdio_data; /* first 4byte mdio */
> > > __be16 hdr; /* qca hdr */
> > > } __packed;
> >
> > It looks odd that hdr is BE while the rest are LE. Did you check this?
> >
> > Andrew
>
> Yes we did many test to analyze this and I just checked with some
> tcpdump that the hdr is BE everytime.

That might actual make sense. The comment says:

> > > /* Special struct emulating a Ethernet header */

And hdr is where the Ether type would be, which is network endian,
i.e. big endian.

Andrew