On Mon, Nov 21, 2022 at 09:58:41AM +0100, Jiri Slaby wrote: > On 18. 11. 22, 15:55, Gabriel Somlo wrote: > > Switch the TX path to IRQ-driven operation, while maintaining support > > for polling mode via the poll timer. > > > > Signed-off-by: Gabriel Somlo <gsomlo@xxxxxxxxx> > > Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> > ... > > @@ -154,6 +148,8 @@ static irqreturn_t liteuart_interrupt(int irq, void *data) > > isr = litex_read8(port->membase + OFF_EV_PENDING) & uart->irq_reg; > > if (isr & EV_RX) > > liteuart_rx_chars(port); > > + if (isr & EV_TX) > > + liteuart_tx_chars(port); > > Wait, how do you ensure the OFF_EV_PENDING reg contains EV_RX and/or EV_TX > in the polling mode? The hardware (well, *gateware*) is coded to populate the EV_PENDING register regardless of whether IRQs are enabled via the EV_ENABLE register (or indeed, whether IRQs are even "wired into" the design at all). See https://github.com/enjoy-digital/litex/blob/master/litex/soc/cores/uart.py and https://github.com/enjoy-digital/litex/blob/master/litex/soc/interconnect/csr_eventmanager.py for a starting point on why it's OK to just assume that... Thanks, --Gabriel
