Re: [PATCH v5 08/14] serial: 8250_mxpcie: speed up TX using memory-mapped FIFO window

[Jiri Slaby]

On 02. 08. 26, 11:10, Andy Shevchenko wrote:
> On Fri, Jul 31, 2026 at 10:49 AM Crescent Hsieh
> <crescentcy.hsieh@xxxxxxxx> wrote:
> > The MUEx50 UART provides a memory-mapped TX FIFO data window along with
> > a TX FIFO level counter.
> >
> > Fill the TX FIFO in bulk via the MMIO FIFO window based on available
> > FIFO space, using uart_port_tx_limited() for the common serial-core TX
> > handling.
>
> ...
>
> > +static void mxpcie8250_tx_chars(struct uart_8250_port *up)
> > +{
> > +       struct uart_port *port = &up->port;
> > +       unsigned int offset = 0;
> > +       unsigned char c;
> > +
> > +       uart_port_tx_limited(port, c, port->fifosize - serial_in(up, MOXA_PUART_TX_FIFO_CNT),
> > +                            true,
> > +                            serial_out(up, MOXA_PUART_TX_FIFO_MEM + offset++, c),
> > +                            ({}));
> > +}
>
> At least three randomly chosen drivers use the empty tx_done, perhaps
> it's time to have a helper that embeds this ugly piece in it and hides
> from the driver?

I haven't tried, can we make the helper a variadic macro?

--
js
suse labs