Re: [RFC PATCH 2/3] net: sparx5: Add Sparx5 switchdev driver

[Steen Hegelund]

On 29.11.2020 18:16, Andrew Lunn wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> > diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_ethtool.c b/drivers/net/ethernet/microchip/sparx5/sparx5_ethtool.c
> > new file mode 100644
> > index 000000000000..a91dd9532f1c
> > --- /dev/null
> > +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_ethtool.c
> > @@ -0,0 +1,1027 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/* Microchip Sparx5 Switch driver
> > + *
> > + * Copyright (c) 2020 Microchip Technology Inc. and its subsidiaries.
> > + */
> > +
> > +#include <linux/ethtool.h>
> > +
> > +#include "sparx5_main.h"
> > +#include "sparx5_port.h"
> > +
> > +/* Add a potentially wrapping 32 bit value to a 64 bit counter */
> > +static inline void sparx5_update_counter(u64 *cnt, u32 val)
> > +{
> > +     if (val < (*cnt & U32_MAX))
> > +             *cnt += (u64)1 << 32; /* value has wrapped */
> > +
> > +     *cnt = (*cnt & ~(u64)U32_MAX) + val;
> > +}
>
> No inline functions in C files. Let the compiler decide.
>
> And i now think i get what this is doing. But i'm surprised at the
> hardware. Normally registers like this which are expected to wrap
> around, reset to 0 on read.
>
>        Andrew

Hi Andrew,

I will remove the inline.

In our case the counters just wraps around (at either 32 or 40 bit).

Thanks for your comments

BR
Steen

---------------------------------------
Steen Hegelund
steen.hegelund@xxxxxxxxxxxxx