Re: [PATCH v5 05/14] serial: 8250_mxpcie: offload XON/XOFF flow control to MUEx50 hardware

From: Andy Shevchenko

Date: Sun Aug 02 2026 - 05:03:15 EST


On Fri, Jul 31, 2026 at 10:49 AM Crescent Hsieh
<crescentcy.hsieh@xxxxxxxx> wrote:
>
> The MUEx50 UART can handle in-band software flow control (XON/XOFF)
> directly in hardware.
>
> Program the on-chip XON/XOFF characters from termios settings and enable
> the corresponding MUEx50 flow control modes when IXON or IXOFF is
> requested. Provide throttle and unthrottle callbacks so RX can be
> stopped and resumed cleanly.

...

> #define MOXA_PUART_EFR_AUTO_RTS BIT(6)
> #define MOXA_PUART_EFR_AUTO_CTS BIT(7)
> #define MOXA_PUART_EFR_RX_FLOW_MASK GENMASK(1, 0)
> +#define MOXA_PUART_EFR_RX_FLOW_DISABLED 0x0
> +#define MOXA_PUART_EFR_RX_FLOW_XON2_XOFF2 0x1
> +#define MOXA_PUART_EFR_RX_FLOW_XON1_XOFF1 0x2
> +#define MOXA_PUART_EFR_RX_FLOW_COPY_TX 0x3
> #define MOXA_PUART_EFR_TX_FLOW_MASK GENMASK(3, 2)

> -

^^^

> +#define MOXA_PUART_EFR_TX_FLOW_DISABLED 0x0
> +#define MOXA_PUART_EFR_TX_FLOW_XON2_XOFF2 0x1
> +#define MOXA_PUART_EFR_TX_FLOW_XON1_XOFF1 0x2
> +#define MOXA_PUART_EFR_TX_FLOW_RESERVED 0x3
> +

^^^

Why is this blank line changed? What happened?

> +#define MOXA_PUART_XON1 0x0B
> +#define MOXA_PUART_XON2 0x0C
> +#define MOXA_PUART_XOFF1 0x0D
> +#define MOXA_PUART_XOFF2 0x0E


--
With Best Regards,
Andy Shevchenko