Hi Biju,
On Fri, Mar 24, 2023 at 11:02 AM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> Add SCIF DMA rx support for RZ/G2L alike SoCs.
>
> RZ/G2L alike SoCs use the same signal for both interrupt and DMA transfer
> requests, so we must disable line interrupt while transferring DMA.
>
> We must set FIFO trigger to 1 so that SCIF will request DMA when there is
> a character as SCIF DMA request is based on FIFO data full RDF.
>
> Based on a patch in the BSP by Long Luu
> <long.luu.ur@xxxxxxxxxxx>
>
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Thanks for your patch!
> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -1312,9 +1312,13 @@ static void sci_dma_rx_reenable_irq(struct sci_port *s)
>
> /* Direct new serial port interrupts back to CPU */
> scr = serial_port_in(port, SCSCR);
> - if (port->type == PORT_SCIFA || port->type == PORT_SCIFB) {
> - scr &= ~SCSCR_RDRQE;
> + if (port->type == PORT_SCIFA || port->type == PORT_SCIFB ||
> + is_rz_scif_port(port, s)) {
> enable_irq(s->irqs[SCIx_RXI_IRQ]);
> + if (port->type == PORT_SCIF)
> + scif_set_rtrg(port, s->rx_trigger);
> + else
> + scr &= ~SCSCR_RDRQE;
> }
> serial_port_out(port, SCSCR, scr | SCSCR_RIE);
> }
> @@ -1735,7 +1739,15 @@ static irqreturn_t sci_rx_interrupt(int irq, void *ptr)
> if (sci_dma_rx_submit(s, false) < 0)
> goto handle_pio;
>
> - scr &= ~SCSCR_RIE;
> + if (is_rz_scif_port(port, s)) {
> + /* Switch irq from SCIF to DMA */
> + disable_irq_nosync(s->irqs[SCIx_RXI_IRQ]);
Perhaps this can be combined with the disable_irq_nosync() above?
> + scif_set_rtrg(port, 1);
> + /* DMA need RIE enable */
> + scr |= SCSCR_RIE;
> + } else {
> + scr &= ~SCSCR_RIE;
> + }
... and this with some other SCIFA code path?
Looks like RZ/A2 and RZ/G2L "SCIFA" does have some resemblance with
SCIFA, contrary to earlier statements?
Perhaps the code can be simplified by treating it even more like
a SCIFA?
> }
> serial_port_out(port, SCSCR, scr);
> /* Clear current interrupt */
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
