Re: [PATCH 3/4] mailbox: add direct synchronous send support

[Jassi Brar]

On Wed, Sep 30, 2026 at 10:06 AM Anup Patel <anup.patel@xxxxxxxxxxxxxxxx> wrote:
>
> From: Amirreza Zarrabi <amirreza.zarrabi@xxxxxxxxxxxxxxxx>
>
> Some mailbox controllers can complete a transaction entirely within
> the calling context, without going through the queued TX state
> machine or a TX-done interrupt. Add a synchronous send path so their
> clients can request one and wait for the result directly.
>
> Controllers advertise support via the new send_data_sync() op and
> clients opt in by setting tx_sync when requesting the channel.
>
> Channels bound this way must not call mbox_chan_txdone() or
> mbox_client_txdone(), and mbox_send_message() and mbox_flush() now
> reject them, since only mbox_send_message_sync() is a valid
> transmit path. The client remains responsible for serializing calls
> to mbox_send_message_sync() against mbox_free_channel().
>
Seems like you want to use mbox_client.tx_block.

Regards,
Jassi