Re: [PATCH 2/2] nvmem: iomap: new driver exposing NVMEM accessible using I/O mapping

[Srinivas Kandagatla]

On 05/03/2021 10:24, Rafał Miłecki wrote:
> > > +static int iomap_read(void *context, unsigned int offset, void *val,
> > > +              size_t bytes)
> > > +{
> > > +    struct iomap *priv = context;
> > > +    u8 *src = priv->base + offset;
> > > +    u8 *dst = val;
> > > +    size_t tmp;
> > > +
> > > +    tmp = offset % 4;
> > > +    memcpy_fromio(dst, src, tmp);
> > > +    dst += tmp;
> > > +    src += tmp;
> > > +    bytes -= tmp;
> > > +
> > > +    tmp = rounddown(bytes, 4);
> > > +    __ioread32_copy(dst, src, tmp / 4);
> > > +    dst += tmp;
> > > +    src += tmp;
> > > +    bytes -= tmp;
> > > +
> > > +    memcpy_fromio(dst, src, bytes);
> > > +
> >
> >
> > You could just do this!
> >
> >      while (bytes--)
> >          *val++ = readb(priv->base + offset + i++);
>
> Do you mean that as replacement for "memcpy_fromio" or the whole
> function code?

Yes please!

> The reason for using __ioread32_copy() was to improve reading
> performance (using aligned 32 bit access where possible). I'm not sure
> if that really matters?

Just simple while loop is much readable than the previous code TBH!

>

> P.S.
> Please don't yell at me in every sentence :( Makes me a bit sad :(
Sorry!! I did not mean anything as such! :-)

--srini