On Fri, Mar 03, 2023 at 09:50:00AM +0800, lihuisong (C) wrote:
>
> 在 2023/3/2 21:52, Sudeep Holla 写道:
> > On Thu, Mar 02, 2023 at 09:57:35AM +0800, lihuisong (C) wrote:
> > > 在 2023/3/1 21:24, Sudeep Holla 写道:
> > [...]
> >
> > > > +static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan)
> > > > +{
> > > > + u64 val;
> > > > + int ret;
> > > > +
> > > > + ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
> > > > + if (ret)
> > > > + return false;
> > > > +
> > > we indeed already check if cmd_complete register is exist.
> > > IMO, it can simply the code logic and reduce the risk of problems if we
> > > return true here for the type without this register.
> > > what do you think?
> > >
> > IIUC, your concern is about returning true for type 4 when the register
> > doesn't exist, right ?
> Return true in advance for the type without the cmd_complete register.
> If support the register, we judge if the channel should respond the
> interrupt based on the value of cmd_complete, like bellow.
Right, sorry for missing that.
>
> -->8
> +static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan)
> +{
> + u64 val;
> + int ret;
> +
> + ret = pcc_chan_reg_read(&pchan->cmd_complete, &val);
> + if (ret)
> + return false;
> +
> + if (!pchan->cmd_complete.gas)
> + return true;
> +
Yes we need the above check.
> + /*
> + * Judge if the channel respond the interrupt based on the value of
> + * command complete.
> + */
> + val &= pchan->cmd_complete.status_mask;
> + /*
> + * If this is PCC slave subspace channel, then the command complete
> + * bit 0 indicates that Platform is sending a notification and OSPM
> + * needs to respond this interrupt to process this command.
> + */
> + if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
> + return !val;
> + else
> + return !!val;
> +}
> > I am saying it won't happen as we bail out if there is no GAS register
> > from pcc_chan_reg_init(). Or am I missing something here ?
> Yes, what you say is also ok. Just wondering if it is better to simply the
> logic.
Understood now.
> > > > + val &= pchan->cmd_complete.status_mask;
> > > > +
> > > > + /*
> > > > + * If this is PCC slave subspace channel, then the command complete
> > > > + * bit 0 indicates that Platform is sending a notification and OSPM
> > > > + * needs to respond this interrupt to process this command.
> > > > + */
> > > > + if (pchan->type == ACPI_PCCT_TYPE_EXT_PCC_SLAVE_SUBSPACE)
> > > > + return !val;
> > > > + else
> > > > + return !!val;
> > > This else branch is not applicable to type 3. type 3 will cannot respond
> > > interrupt.
> > Sorry I don't understand what you mean by that.
> Sorry for my mistake.
> I meant that the type2 channel always return false in this function and
> never respond the interrupt if no check for the GAS register.
> Because the 'val' for the type without the register is zero.
> >
Agreed as mentioned above, we need to bail out with true return if no GAS is
found.
--
Regards,
Sudeep
