Re: [PATCH] hw/net/imx_fec: write TGSR and TCSR3 in imx_enet_write()

[Peter Maydell <peter.maydell@linaro.org>]

On Tue, 25 Feb 2020 at 05:41, Jason Wang <jasowang@redhat.com> wrote:
>
>
> On 2020/2/25 上午10:59, Chen Qun wrote:
> > The current code causes clang static code analyzer generate warning:
> > hw/net/imx_fec.c:858:9: warning: Value stored to 'value' is never read
> >          value = value & 0x0000000f;
> >          ^       ~~~~~~~~~~~~~~~~~~
> > hw/net/imx_fec.c:864:9: warning: Value stored to 'value' is never read
> >          value = value & 0x000000fd;
> >          ^       ~~~~~~~~~~~~~~~~~~
> >
> > According to the definition of the function, the two “value” assignments
> >   should be written to registers.
> >
> > Reported-by: Euler Robot <euler.robot@huawei.com>
> > Signed-off-by: Chen Qun <kuhn.chenqun@huawei.com>
> > ---
> > I'm not sure if this modification is correct, just from the function
> >   definition, it is correct.
> > ---
> >   hw/net/imx_fec.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c
> > index 6a124a154a..92f6215712 100644
> > --- a/hw/net/imx_fec.c
> > +++ b/hw/net/imx_fec.c
> > @@ -855,13 +855,13 @@ static void imx_enet_write(IMXFECState *s, uint32_t index, uint32_t value)
> >           break;
> >       case ENET_TGSR:
> >           /* implement clear timer flag */
> > -        value = value & 0x0000000f;
> > +        s->regs[index] = value & 0x0000000f;
> >           break;

Hi; the datasheet for this SoC says that these bits
of the register are write-1-to-clear, so while this
is definitely a bug I don't think this is the right fix.

> >       case ENET_TCSR0:
> >       case ENET_TCSR1:
> >       case ENET_TCSR2:
> >       case ENET_TCSR3:
> > -        value = value & 0x000000fd;
> > +        s->regs[index] = value & 0x000000fd;
> >           break;

Here bit 7 is write-1-to-clear, though bits 0 and
2..5 are simple write-the-value.

> >       case ENET_TCCR0:
> >       case ENET_TCCR1:
>
>
> Applied.

Could you drop this from your queue, please?

thanks
-- PMM