[U-Boot] [PATCH 4/5] include: dma: Update the function description for dma_memcpy

[Chee, Tien Fong <tien.fong.chee@intel.com>]

On Fri, 2018-06-08 at 13:59 -0800, Simon Glass wrote:
> Hi,
> 
> On 3 June 2018 at 23:14, Chee, Tien Fong <tien.fong.chee@intel.com>
> wrote:
> > 
> > On Fri, 2018-06-01 at 08:25 -0600, Simon Glass wrote:
> > > 
> > > Hi,
> > > 
> > > On 31 May 2018 at 02:08,  <tien.fong.chee@intel.com> wrote:
> > > > 
> > > > 
> > > > From: Tien Fong Chee <tien.fong.chee@intel.com>
> > > > 
> > > > Update the dma_memcpy description on return argument for DMA330
> > > > driver.
> > > > 
> > > > Signed-off-by: Tien Fong Chee <tien.fong.chee@intel.com>
> > > > ---
> > > >  include/dma.h | 4 ++--
> > > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > > 
> > > > diff --git a/include/dma.h b/include/dma.h
> > > > index 0a0c9dd..b825c1e 100644
> > > > --- a/include/dma.h
> > > > +++ b/include/dma.h
> > > > @@ -79,8 +79,8 @@ int dma_get_device(u32 transfer_type, struct
> > > > udevice **devp);
> > > >   * @dst - destination pointer
> > > >   * @src - souce pointer
> > > >   * @len - data length to be copied
> > > > - * @return - on successful transfer returns no of bytes
> > > > -            transferred and on failure return error code.
> > > > + * @return - on successful transfer returns no of bytes or
> > > > zero(for DMA330)
> > > > + *          transferred and on failure return error code.
> > > This is a public API so you cannot change it just for one device.
> > > You
> > > can change the API for everyone if you like.
> > > 
> > > But why would it want to return 0?
> > > 
> > Because we only able to check the DMA tranferring status, full
> > transfer
> > or failed. I can return the len argument user set if full tranfer
> > is
> > finished.
> OK. My concern is that you have a comment saying that the function
> does something different for one device versus others. This is not
> the
> place for such a comment. Here you can just document that it can
> return two possible meanings. You should add comments explaining what
> 0 means too (e.g. completed, but length unknown?).
> 
> For something in progress, you should use -EINPROGRESS / -EAGAIN
> 
Okay.
> Regards,
> Simon