Re: [PATCH 1/3] xen/arm: vpl011: Fix misleading comments

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 6 Apr 2023, Ayan Kumar Halder wrote:
> On 05/04/2023 12:17, Michal Orzel wrote:
> > In both vpl011_read_data() and vpl011_read_data_xen(), there is a comment
> > stating that the guest is expected to read the DR register only if the
> > TXFE bit of FR register is not set. This is obviously logically wrong and
> > it should be RXFE (i.e. RX FIFO empty bit set -> nothing to read).
> NIT:- I will prefer if the PL011 TRM is mentioned with the relevant section.
> > 
> > Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx>
> Reviewed-by: Ayan Kumar Halder <ayan.kumar.halder@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> > ---
> >   xen/arch/arm/vpl011.c | 8 ++++----
> >   1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/xen/arch/arm/vpl011.c b/xen/arch/arm/vpl011.c
> > index 2fa80bc15ac4..0186d8a31834 100644
> > --- a/xen/arch/arm/vpl011.c
> > +++ b/xen/arch/arm/vpl011.c
> > @@ -143,8 +143,8 @@ static uint8_t vpl011_read_data_xen(struct domain *d)
> >       /*
> >        * It is expected that there will be data in the ring buffer when this
> >        * function is called since the guest is expected to read the data
> > register
> > -     * only if the TXFE flag is not set.
> > -     * If the guest still does read when TXFE bit is set then 0 will be
> > returned.
> > +     * only if the RXFE flag is not set.
> > +     * If the guest still does read when RXFE bit is set then 0 will be
> > returned.
> >        */
> >       if ( xencons_queued(in_prod, in_cons, sizeof(intf->in)) > 0 )
> >       {
> > @@ -202,8 +202,8 @@ static uint8_t vpl011_read_data(struct domain *d)
> >       /*
> >        * It is expected that there will be data in the ring buffer when this
> >        * function is called since the guest is expected to read the data
> > register
> > -     * only if the TXFE flag is not set.
> > -     * If the guest still does read when TXFE bit is set then 0 will be
> > returned.
> > +     * only if the RXFE flag is not set.
> > +     * If the guest still does read when RXFE bit is set then 0 will be
> > returned.
> >        */
> >       if ( xencons_queued(in_prod, in_cons, sizeof(intf->in)) > 0 )
> >       {
>