Re: [Patch v6 1/4] memory: tegra: Add memory controller channels support

[Ashish Mhetre]

On 4/10/2022 7:48 PM, Dmitry Osipenko wrote:
> External email: Use caution opening links or attachments
>
>
> 06.04.2022 08:24, Ashish Mhetre пишет:
> > +     num_dt_channels = of_property_count_elems_of_size(pdev->dev.of_node, "reg",
> > +                                                       reg_cells * sizeof(u32));
> > +     /*
> > +      * On tegra186 onwards, memory controller support multiple channels.
> > +      * Apart from regular memory controller channels, there is one broadcast
> > +      * channel and one for stream-id registers.
> > +      */
> > +     if (num_dt_channels < mc->soc->num_channels + 2) {
> > +             dev_warn(&pdev->dev, "MC channels are missing, please update memory controller DT node with MC channels\n");
> > +             return 0;
> > +     }
> > +
> > +     mc->bcast_ch_regs = devm_platform_ioremap_resource_byname(pdev, "mc-broadcast");
> > +     if (IS_ERR(mc->bcast_ch_regs))
> > +             return PTR_ERR(mc->bcast_ch_regs);
>
> Looks to me that you don't need to use of_property_count_elems_of_size()
> and could only check the "mc-broadcast" presence to decide whether this
> is an older DT.
Now that we are using reg-names in new DT, yes it'd be fine to just
check mc-broadcast to decide it's a new or old DT.

> mc->bcast_ch_regs = devm_platform_ioremap_resource_byname(pdev,
> "broadcast");
> if (IS_ERR(mc->bcast_ch_regs)) {
>          dev_warn(&pdev->dev, "Broadcast channel is missing, please update your
> device-tree\n");
>          return PTR_ERR(mc->bcast_ch_regs);
> }

return 0;

to avoid DT ABI break, right?