Re: [PATCH v5 2/2] mailbox: mediatek: Add mtk-vcp-mailbox driver

Jjian Zhou (周建)
2025-09-24T02:21:41Z

On Tue, 2025-09-23 at 08:11 -0500, Jassi Brar wrote:
> External email : Please do not click links or open attachments until
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>
> On Tue, Sep 23, 2025 at 1:46 AM Jjian Zhou (周建) <
> Jjian.Zhou@mediatek.com> wrote:
> >
> > On Thu, 2025-09-18 at 18:50 -0500, Jassi Brar wrote:
> > > External email : Please do not click links or open attachments
> > > until
> > > you have verified the sender or the content.
> > >
> > >
> > > On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <
> > > jjian.zhou@mediatek.com>
> > > wrote:
> > >
> > > .....
> > >
> > > > +#include <linux/module.h>
> > > > +#include <linux/of.h>
> > > > +#include <linux/platform_device.h>
> > > > +#include <linux/slab.h>
> > > > +
> > > > +struct mtk_vcp_mbox_priv {
> > >
> > > Maybe 'mtk_vcp_mbox' is a more appropriate name ?
> > >
> > > > + void __iomem *base;
> > > > + struct device *dev;
> > > > + struct mbox_controller mbox;
> > > > + const struct mtk_vcp_mbox_cfg *cfg;
> > > > + struct mtk_ipi_info ipi_recv;
> > >
> > > Maybe also have "struct mbox_chan chan[1]; " so that you don't
> > > have
> > > to
> > > allocate one during the probe.
> > > Also if you have "struct mbox_controller mbox;" as the first
> > > member,
> > > you could simply typecast that to get this structure.
> > > Something like "struct mpfs_mbox" in mailbox-mpfs.c
> > >
> >
> >
> > ERROR:FLEXIBLE_ARRAY: Use C99 flexible arrays - see
> >
https://urldefense.com/v3/__https://docs.kernel.org/process/deprecated.html*zero-length-and-one-element-arrays__;Iw!!CTRNKA9wMg0ARbw!kLlX71HetZwXMZ9UmdtvMEKKykbZINIUNVW5nLVfoztdkSJMlaa3QfbzZxGKIkSgqmHHc2Lvfwpj4URsOVCtekNCFh5L$
> > #81: FILE: drivers/mailbox/mtk-vcp-mailbox.c:24:
> > + struct mbox_chan chans[1];
> > +};
> >
> > Can we ignore this error?
> >
>
> It seems single element style is deprecated. While we know what we
> are
> doing, let us placate that error by
> struct mbox_chan mch;
> struct mbox_chan chans[];
> and set chans = &mch

Do you have any specific considerations for suggesting this approach?
Wo
uld it be sufficient to just define a 'struct mbox_chan chans'?