Hi,
On Thu, 19 Sep 2019 at 11:10, Lanqing Liu <liuhhome@xxxxxxxxx> wrote:
>
> In order to access the UART without the interrupts, the kernel uses
> the basic polling methods for IO with the device. With these methods
> implemented, it is now possible to enable kgdb during early boot over serial.
>
> Signed-off-by: Lanqing Liu <liuhhome@xxxxxxxxx>
> ---
> Change from v1:
> - Add poll_init() support.
Looks good to me and the KGDB can work well on my board, so feel free
to add my tags:
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
Tested-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
> ---
> drivers/tty/serial/sprd_serial.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/drivers/tty/serial/sprd_serial.c b/drivers/tty/serial/sprd_serial.c
> index 73d71a4..d833160 100644
> --- a/drivers/tty/serial/sprd_serial.c
> +++ b/drivers/tty/serial/sprd_serial.c
> @@ -911,6 +911,34 @@ static void sprd_pm(struct uart_port *port, unsigned int state,
> }
> }
>
> +#ifdef CONFIG_CONSOLE_POLL
> +static int sprd_poll_init(struct uart_port *port)
> +{
> + if (port->state->pm_state != UART_PM_STATE_ON) {
> + sprd_pm(port, UART_PM_STATE_ON, 0);
> + port->state->pm_state = UART_PM_STATE_ON;
> + }
> +
> + return 0;
> +}
> +
> +static int sprd_poll_get_char(struct uart_port *port)
> +{
> + while (!(serial_in(port, SPRD_STS1) & SPRD_RX_FIFO_CNT_MASK))
> + cpu_relax();
> +
> + return serial_in(port, SPRD_RXD);
> +}
> +
> +static void sprd_poll_put_char(struct uart_port *port, unsigned char ch)
> +{
> + while (serial_in(port, SPRD_STS1) & SPRD_TX_FIFO_CNT_MASK)
> + cpu_relax();
> +
> + serial_out(port, SPRD_TXD, ch);
> +}
> +#endif
> +
> static const struct uart_ops serial_sprd_ops = {
> .tx_empty = sprd_tx_empty,
> .get_mctrl = sprd_get_mctrl,
> @@ -928,6 +956,11 @@ static void sprd_pm(struct uart_port *port, unsigned int state,
> .config_port = sprd_config_port,
> .verify_port = sprd_verify_port,
> .pm = sprd_pm,
> +#ifdef CONFIG_CONSOLE_POLL
> + .poll_init = sprd_poll_init,
> + .poll_get_char = sprd_poll_get_char,
> + .poll_put_char = sprd_poll_put_char,
> +#endif
> };
>
> #ifdef CONFIG_SERIAL_SPRD_CONSOLE
> --
> 1.9.1
>
--
Baolin Wang
Best Regards
