Re: [PATCH v2 2/9] serial: bflb_uart: add Bouffalolab UART Driver

Jisheng Zhang
2022-11-28T14:31:36Z

On Mon, Nov 28, 2022 at 07:10:41AM +0100, Jiri Slaby wrote:
> On 27. 11. 22, 14:24, Jisheng Zhang wrote:
> > +static void bflb_uart_tx_chars(struct uart_port *port)
>
> Again:
>
> Are you unable to use the TX helper? If so:

You know serial subsystem better than me, may I ask for more
details? For example,
Besides uart_xmit_advance(), do you expect other TX helpers? If yes,
can you please list them?

> * why?
> * use uart_advance_xmit() at least.

Do you mean uart_xmit_advance()? in the do while loop below?

I'm not sure I understand the meaning, correct me If I misunderstand
something.

thanks
>
> > +{
> > + struct circ_buf *xmit = &port->state->xmit;
> > + unsigned int count;
> > +
> > + if (port->x_char) {
> > + /* Send special char - probably flow control */
> > + wrl(port, UART_FIFO_WDATA, port->x_char);
> > + port->x_char = 0;
> > + port->icount.tx++;
> > + return;
> > + }
> > +
> > + if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
> > + bflb_uart_stop_tx(port);
> > + return;
> > + }
> > +
> > + count = BFLB_UART_TX_FIFO_TH;
> > + do {
> > + wrl(port, UART_FIFO_WDATA, xmit->buf[xmit->tail]);
> > + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
> > + port->icount.tx++;
> > + if (uart_circ_empty(xmit))
> > + break;
> > + } while (--count > 0);
> > +
> > + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
> > + uart_write_wakeup(port);
> > +
> > + if (uart_circ_empty(xmit))
> > + bflb_uart_stop_tx(port);
> > +}
>
> --
> js
> suse labs