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 >